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    Integrated usage of historical geospatial data and modern satellite images reveal long-term land use/cover changes in Bursa/Turkey, 1858–2020

    Data UsedWe used cadastral maps from 1858 to reconstruct the LULC structure of Aksu and Kestel for the mid-nineteenth century. General Staff of the Ottoman Army produced these maps in 1:10,000 scale. These maps were one of the earliest attempts of creating cadastral maps in the Ottoman Empire. The images of historical maps scanned at 1270 dpi resolutions are provided by the Turkish Presidency State Archives of the Republic of Turkey – Department of Ottoman Archives (Map collection, HRT.h, 561–567). Individual tiles of cadastral maps are of a 1:2,000 scale. However, these maps are kept separated from their accompanying cadastral registers or documentation regarding their production process in the archives. There are no studies on the production of these cadastral maps, but few studies used them until now35,36.The LULC structures of Aksu and Kestel for the mid-twentieth century were generated using aerial photographs from June 23, 1955, with a scale of 1:30,000. These aerial photographs were captured by the US Navy Photographic Squadron VJ-62 (established on April 10, 1952, re-designated to VAP-62 on July 1956, and disestablished on October 15, 1969). The squadron conducted mapping and special photographic projects worldwide37. Lastly, the VHR satellite images of WorldView-3 (WV-3) with 0.3 m of spatial resolution, collected on September 6, 2020, were used to show the up-to-date LULC patterns of Aksu and Kestel.MethodologyFigure 2 shows the flowchart of steps followed in this study to detect the LULC changes. The workflow includes three phases: preprocessing, LULC mapping, and statistical analysis of LULC changes.Figure 2Flowchart of the processing steps for the LULC change analysis for Kestel.Full size imageData preprocessingOrthorectification is the first important step in ensuring accurate spatial positioning among the multi-temporal and multi-source images, eliminating geometric distortions, and defining all data sets on a common projection system. To align the multi-modal geospatial datasets, we first performed the orthorectification of the satellite images and then we used the orthorectified satellite images as reference for the georeferencing of the cadastral maps and aerial photographs.Satellite imagery orthorectificationWe first pan-sharpened the WV-3 images by applying the PANSHARP2 algorithm38 to fuse the panchromatic (PAN) image of 0.3 m spatial resolution with four multispectral bands (R, G, B, and near-infrared (NIR)) of 1.2 m. We then geometrically corrected the pan-sharpened (PSP) WV-3 imageries using an ALOS Global Digital Surface Model with a horizontal resolution of approximately 30 m (ALOS World 3D – 30 m), rational polynomial coefficients (RPC) file, and additional five ground control points (GCPs) for the refinement. As a geometric model, we used the RPC model with zero-order polynomial adjustment39, and orthorectified images were registered to the Universal Traverse Mercator (UTM) Zone 35 N as the reference coordinate system.Georeferencing of scanned cadastral maps and aerial photographsWe used orthorectified WV-3 imageries as a reference for the geometric correction of the historical cadastral maps and the aerial photographs. We selected the spline (triangulation) transformation, a rubber sheeting method, useful for local accuracy and requiring a minimum of 10 control points, as the transformation method to determine the correct map coordinate location for each cell in the historical maps and aerial photographs. The spline transformation provides superior accuracies for the geometric correction of the historical geospatial data40,41.The lack of topographic properties of planimetric features in the historical cadastral maps and the inherent distortions of the aerial photographs due to terrain and camera tilts causes difficulties in precise georeferencing of these data sets. It increases the number of required ground control points (GCPs) for optimal image rectification. Adequate and homogenously distributed GCPs, identified from cadastral maps and aerial photographs, can ensure precise spatial alignment among different geospatial data. The best locations for GCPs were border intersections of agricultural fields and roads. As for artificial objects, places of worship and schools, which are highly probable that have remained unchanged, are other optimal locations for GCPs to perform the accurate geometric correction. Figure 3 displays samples of GCPs selected from cadastral maps and aerial photographs. We obtained 2.11 m or better overall RMSE (Root Mean Square Error) values for the geometric correction of the historical maps and aerial photographs.Figure 3Examples of GCPs selection (red crosses in blue circles) on (a), (c) Cadastral maps and their counterparts on (b), (d) Aerial photographs.Full size imageLULC classification schemeWe defined our classification scheme by analyzing the LULC classes distinguished in all three datasets (i.e., cadastral maps, aerial photographs, and WV-3 imageries). We used the classification scheme shown in Table 1. We also present codes and names of the land cover (LC) classes derived from Corine LC nomenclature42.Table 1 Classification scheme of the study.Full size tableThe legends provided on the historical cadastral maps of Aksu and Kestel delineate 15 LULC categories, which are: (1) buildings, (2) home gardens, (3) roads, (4) arable land, (5) gardens, (6) mulberry groves, (7) chestnut groves, (8) olive groves, (9) vegetable gardens, (10) forest, (11) courtyards, (12) vineyards, (13) arable fields, (14) cemeteries, (15) watercourses. Categorizing the land cover types of cadastral maps is limited with the classes available in the map legend. The legend of cadastral maps categorizes the forested area in one class named “forest”. Therefore, it was not possible to use third-level LC sub-categories in our classification schema for forest area which is separating forested areas into three subclasses (3.1.1, 3.1.2, and 3.1.3) according to the type of tree cover. Although some of the third-level LC sub-categories could be extracted from the cadastral map legend, it was not possible to extract all third level agricultural classes from single-band monochromatic aerial photographs. Although the spatial extent of fruit trees as a permanent crop could be determined from aerial photographs, it was not possible to classify these trees into different fruit types (e.g. 2.2.1 Vineyards, 2.2.2 Fruit trees and berry plantations, 2.2.3 Olive groves). Limitation on the number of forest classes is due to the historical cadastral map content; whereas limitation on the number of agricultural classes is mainly offset by the aerial photographs which have only one spectral band and we did not have any field survey or ancillary geographical data that could help the specific identification of fruit trees.Our primary focus is to find out agricultural land abandonment, deforestation/afforestation, urbanization, and rural depopulation within the historical periods. Therefore, most of the second level LULC classes are sufficient for our purpose. LULC changes within the third class level such as the conversion of third level agriculture classes among each other were not aimed to analyze in this research. Our datasets allow us to use Level 3 CORINE classes for the artificial surfaces. These classes are useful to determine residential area implications of rural depopulation or urbanization, one of the focused transformation types for our analysis.We re-organized and categorized the LULC types used in the cadastral maps, with minimum possible manipulation (only for 2.4 and 3.2 LC classes) according to the classification scheme, as shown in Table 2.Table 2 Correspondence between Corine Land Cover and historical cadastral maps nomenclature.Full size tableLULC mappingAfter aligning all geospatial data, we used the georeferenced cadastral maps, aerial photographs, and satellite images for the LULC mapping. We set the spatial extent of the selected regions based on boundaries digitized from the cadastral maps of 1858. Then we detected historical LULC changes within these extents for all geospatial datasets covering 1900 ha and 830 ha of the Aksu and Kestel regions, respectively. Figures 4 and 5 show the selected extents from the historical maps, aerial photographs, and satellite images of the Kestel and Aksu sites, respectively.Figure 4Geospatial dataset for the Kestel study region. (a) 1858 Cadastral map, (b) 1955 aerial photo, and (c) 2020 WV-3 satellite image (finer details shown in the inset images highlighted by Blue boxes).Full size imageFigure 5Geospatial dataset for the Aksu study region. (a) 1858 Cadastral map, (b) 1955 aerial photo, and (c) 2020 WV-3 satellite image (finer details shown in the inset images highlighted by red boxes).Full size imageDigitization of cadastral maps-1858 LULC mapsWe visually interpreted and manually digitized the geographic features on the historical maps and created vector data for each class. The road features in cadastral maps lack topological properties. They also include spatial errors possibly generated in the process of surveying and map production. Therefore, we cross-checked digitized road segments by visual inspection of the road data of the aerial photographs from 1955. We then further modified road polygons to represent accurate road widths. Afterward, we categorized vectorized features of the cadastral maps into the LULC classes defined in Table 1. Finally, we created the vectorized 1858 LULC map. Figure 6 presents the vectorized 1858 cadastral maps of Aksu and Kestel.Figure 6Vectorized cadastral maps of (a) Kestel and (b) Aksu with Red and green lines showing the vector boundaries.Full size imageObject-based image analysis of aerial photographs-1955 LULC mapsAt the second stage of LULC mapping, we performed the segmentation and classification of the aerial photographs using an object-based approach for generating the 1955 LULC map. The object-based image analysis (OBIA) approach in LULC mapping provides advantages over the traditional per-pixel techniques such as higher classification accuracy, depicting more accurate LULC change, and differentiating extra LULC classes33,43,44. We used the eCognition® software (Trimble Germany GmbH, Munich) to implement an object-based image analysis (OBIA). The OBIA approach contains two phases including the segmentation and classification phases that are performed to locate meaningful objects in an image and categorize the created objects, respectively.Multiple ancillary datasets have been used to support different phases of OBIA. The Open Street Map (OSM) vector data, an open-source geospatial dataset (http://www.openstreetmap.org/), has been utilized as ancillary vector data in OBIA to improve the classification of the remotely sensed images. Sertel et al. (2018) used OSM as a thematic layer for road extraction7. Since there are several limitations in extracting the roads from aerial imagery, the OSM road network data could be useful. A majority of unpaved roads in single-band aerial photographs can easily be misclassified as homogeneous areas of arable lands. Precise detection of the roads from monoband aerial photographs without multi-spectral information is difficult. Therefore, we overlaid the OSM road network data with the aerial photographs to extract the revised aerial road vectors through visual interpretation and manual digitization.We segmented the 1955 aerial photographs with the integration of 1858 LULC map produced from cadastral maps. We implemented the multi-resolution segmentation algorithm. In this segmentation method, a parameter called scale determines the size of resulting objects, and the shape and compactness parameters determine the boundaries of objects. The segmentation process of the aerial photographs was performed at multiple stages with various scale, shape, and compactness parameter values. At the initial stage, we segmented the regions according to the 1858 LULC map and we utilized large-scale parameters. The scale parameter was set to 100 and the shape parameter and the compactness were set as 0.7 and 0.3, respectively. At this stage, we focused on interpreting the objects that have not changed between 1858 and 1955. We classified the segments using the thematic layer attribute (LULC classes defined by the cadastral maps) with the highest coverage. Image objects in which the land surface has changed during 1858–1955 period were detected by visual interpretation and unclassified for further segmentation. We followed this approach to reduce the manual effort. We defined unchanged objects between 1858 and 1955 and assigned the same classes of 1858 LULC map to the objects in 1955 aerial photographs. We then segmented the remaining segments, the last time into smaller objects with the scale parameter set as 25, the shape parameter set as 0.2, and the compactness set as 0.8.We classified the remaining unclassified objects through the development of rulesets. An object can be described by several possible features as explanatory variables which are provided by eCognition. In the classification ruleset, different features and parameters can be defined to describe and extract object classes of interest and thresholds for each feature can be defined by the trial-and-error method. We tested sets of variables for the classification of the monoband aerial photographs. Object features such as the mean value of the monoband, texture after Haralick, distance to neighbor objects, shape features (e.g., rectangular fit and asymmetry), and extent features (e.g., area and length/width) were the most useful alternatives. The classification process of the parcels of the aerial photographs with LULC change started with the classification of roads constructed between 1858 and 1955 by utilizing the aerial road map. The watercourse class was the most difficult to classify since shrubs or trees mostly covered the watercourses. These areas were misclassified as forest or agricultural land. Therefore, experts in historical map reading with local geographical information performed the detection and classification of the water course class and interpreted by the cadastral map (1858) and the google map (2020). After roads and watercourses, we classified forest and agricultural lands using the optimal thresholds for the brightness feature. We calculated the thresholds using the single band of the aerial photograph combined with the area and rectangular fit features. The heterogeneous agricultural areas class principally occupied by agriculture with significant areas of natural grass and trees within the same object are separated from the arable lands using the standard deviation of the digital number (DN) values of the aerial photographs. The texture feature helped classify the permanent crops. The brightness, shape, asymmetry, and distance to road class features were the best-performing ones for classifying the remaining artificial surfaces. The manual interpretation was performed for the classification of sub-classes of artificial surface class, including the continuous/discontinuous urban fabric, industrial, commercial, and transport units, mine, dump and construction sites, and artificial, non-agricultural vegetated areas. Since these land use classes contain one or more land cover and land use categories (e.g., artificial non-agriculture land or industrial or commercial units), finding the optimal threshold and exact feature for distinguishing the subclasses of artificial surfaces is difficult. Especially in the case of using the single-band aerial photographs, manual interpretation was required.Object-based image analysis of satellite images-2020 LULC mapsWe segmented WV-3 satellite images using multi-resolution segmentation algorithm and ancillary geographic data. Similar to the aerial road map, the road network of the study region in 2020, named, WV-3 road map, was extracted by overlaying the OSM road data with the WV-3 satellite image. In the segmentation process of the WV-3 image, we used the vector boundaries of the classified aerial photograph (the 1955 LULC map) and the WV-3 road map as ancillary thematic layers. We opted for the same segmentation and classification approach used for the aerial photographs for the WV-3 image.Firstly, we segmented the satellite image into spectrally homogeneous objects using vector data of the 1955 LULC map by applying large-scale parameters. We implemented scale parameter values of 300, 200, 100, and 50 to find the optimal scale to classify objects that have not changed between 1955 and 2020. The best multi-resolution segmentation configuration was the scale of 100 and the shape and compactness parameters of 0.3 and 0.7, respectively. We classified the segments using the thematic layer attribute (LULC classes defined by the aerial maps) with the highest coverage. Segments with LULC change, e.g. the image objects in which the land surface has changed during 1955–2020 period were detected by visual interpretation and unclassified for further segmentation. As a result, we excluded the objects which were remained unchanged during 1955–2020 by assigning the prepared labels which were allocated in the previous step during the classification of 1955 aerial photographs. We then segmented the remaining objects into smaller objects to identify the changed areas in detail. At this step, the scale, shape, and compactness parameters were set as 25, 0.2, and 0.8, respectively.Except for the additional sets of variables utilized to classify the WV-3 images, we applied the rule-set developed for the classification of the aerial photograph for the classification of the remaining objects of 2020 satellite images. The additional sets of variables include the mean of G, B, R, and NIR and two spectral indices, the Normalized Difference Water Index (NDWI), and the Normalized Difference Vegetation Index (NDVI). NDVI was calculated as the normalized difference of reflectance values in the red and NIR bands; whereas , NDWI was determined as the normalized difference of reflectance values of the green and NIR bands. Through the logical conditions, objects having specified values of NDVI and NDWI can be assigned to vegetation and water classes, respectively. The use of NDVI facilitated the delineation of terrains covered by vegetation and the NDWI improved the extraction of water bodies due to its ability to separate water and non-water objects. We separated different sub-classes of agricultural areas and forests by using optimal thresholds for NDVI which were defined by a trial and error method. Also we utilized assigning the optimal threshold to NDWI to separate water bodies from other land covers. In addition, the mean blue band layer was useful in classifying the artificial surfaces. We assessed the accuracy of each classification using error matrices (overall, user’s and producer’s accuracies, and Kappa statistics)45,46.Estimating LULC changes and LULC conversionsAfter the production of LULC maps of Aksu and Kestel for 1858, 1955, and 2020, the vector data of the LULC maps were used to quantify the LULC conversions for two different periods which are 1858–1955 and 1955–2020. To compare the LULC maps of study areas between two different dates of each study period, we provided detailed “from-to” LULC change information by calculating the LULC change transition matrix computed using overlay functions in ArcGIS.We overlaid LULC maps of 1858 and 1955 and intersected the vector boundaries of the 1858 and 1955 LULC maps to determine the conversion types of LULC classes (from which class to which class). Similarly, to quantify the LULC changes between 1955 and 2020, we overlaid the 1955 and 2020 LULC maps. Then we created transition matrices and performed statistical analysis utilizing the matrices. Finally, we discussed the main LULC change types and the driving factors of the changes in the selected study areas. More

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    Inducing metamorphosis in the irukandji jellyfish Carukia barnesi

    Animal husbandryCarukia barnesi polyps were available in culture from the James Cook University Aquarium, spawned from medusa originally collected near Double Island, North Queensland, Australia (16° 43.5′ S, 145° 41.0′ E) in 2014 and 20158. Populations exponentially increase through asexual reproduction8. Detached buds and swimming polyps were collected from the main culture, and transferred into 6-well tissue culture plates in natural filtered seawater. Plates were maintained in darkness to inhibit algae growth at 27 °C in a constant temperature cabinet. Buds and swimming polyps were left to develop and attach to well bottoms, at which point they were then fed freshly hatched Artemia nauplii and water changed 2–3 times per week. Lids remained attached to tissue culture plates to negate water evaporation and maintain a stable salinity. Polyps were maintained in this way for a minimum of 4 months before experiments began, with all individuals matured with the ability to asexually reproduce further buds. To preserve water quality15 polyps were starved for two days prior to experiment start and were not fed for the duration of the trials. One day prior to the experiment start, all immature buds and polyps were removed from wells, leaving approximately 5–10 mature polyps attached to the substrate for analysis.Preparation of reagentsReagentsSix chemicals were trialed in the current study to induce metamorphosis in C. barnesi polyps. Four indole containing compounds were chosen that have previously been trialed with other cubozoan species: 5-methoxy-2-methyl-3-indoleacetic acid, 5-methoxyindole-2-carboxylic acid, 2-methylindole16 and 5-Methoxy-2-methylindole15,16. Along with the retinoic X receptor 9-cis-retinoic acid and lugols solution.Indole compound treatmentsChemical concentrations of indoles documented in the literature were used to conduct preliminary concentration tests. Fifty mM stock solutions were prepared with 100% ethanol, which was diluted with filtered seawater to the desired experimental concentrations: 50 μM16, 20 μM and 5 μM15. Due to high fatality rates at all of these concentrations when used in this study on C. barnesi, all concentrations were diluted. Fifty mM stock solutions of 5-methoxy-2-methyl-3-indoleacetic acid, 5-methoxyindole-2-carboxylic acid, 2-methylindole and 5-Methoxy-2-methylindole were prepared with 50% ethanol (50% Milli-Q® water) and stored at − 20 °C. Fifty mM stock solutions were diluted with filtered seawater to the experimental concentrations of 5 μM, 1 μM, 0.5 μM, 0.1 μM and 0.05 μM. The carrier solution of 50% ethanol (50% Milli-Q® water) was diluted to the equivalent of the experimental concentrations listed above for use as a control, and incorporated into data as concentration 0. Seventeen ml of solution was added to polyps to fill each well of a 6-well plate.Iodine treatment (lugols solution)Aqueous iodine in the form of Lugols solution (0.37% iodine and 0.74% potassium iodide (sigma product information)) was prepared with equivalent concentrations of moles iodine/iodide: 1.5 μM, 3 μM, 6 μM, 12 μM and 24 μM. Filtered seawater only was used a control for this treatment and incorporated into data as concentration 0. 17 ml of solution was added to polyps to fill each well of a 6-well plate.Retinoid treatmentTo reduce ethanol associated fatality of polyps 0.015% ethanol in Milli-Q® water was used to prepare a 1 mM stock solution of 9-cis-Retinoic acid. The 1 mM stock solution was diluted with filtered seawater to the experimental concentrations of 5 μM, 1 μM, 0.5 μM, 0.1 μM and 0.05 μM. The carrier solution of 0.015% ethanol (Milli-Q® water) was diluted to the equivalent of the experimental concentrations listed above for use as a control, and incorporated into data as concentration 0. 17 ml of solution was added to polyps to fill each well of a 6-well plate.Metamorphosis trialsPrimary trialsExperimental concentrations of reagents were added to C. barnesi polyps growing in the wells of sterile 6-well tissue culture plates. One plate was used per chemical, per concentration, in which five wells functioned as replicates containing the chemical being trialed, whilst the sixth well contained only the control medium. Five concentrations were run for each of six chemicals; 30 plates in total.The filtered seawater the polyps were growing in was exchanged for the experimental chemical on day 0, and was not changed for the duration of the trial. Lids remained attached to tissue culture plates to negate water evaporation and hence salinity changes.Polyps in each well were photographed each day through a dissection microscope over a period of 34 days. Results were then recorded from the photographs, categorised (Fig. 6) as the number of polyps which displayed:Tentacle migration: one of the key signs of metamorphosis in this species, polyp tentacles merge, migrating to form four distinct corners in a square shape8.Detached medusa: a medusa formed and detached from the polyp, recorded regardless of health.Mobile detached medusa: a healthy medusa formed and detached from the polyp, with the ability to swim.Polyp survival: this was then used to calculate the number of polyps which survived the treatment which did not metamorphose.Optimisation trialThe optimal chemical and concentration was then deduced by choosing the combination that produced the largest percentage of healthy detached medusa, in this case 5-methoxy-2-methylindole at 1 μM. A final trial was then run with this to determine if length of chemical exposure could optimize healthy medusa yield. Three replicates of a minimum of five polyps were used per treatment, in which in 1 μM of 5-methoxy-2-methylindole (in seawater) was added to polyps for 24, 48, 72, 96 and 120 h, before the solution was changed to fresh seawater. A sea water only control was also run. The total number of healthy detached medusa were recorded each day.Data analysisAll statistical analysis was conducted in IBM SPSS Statistics Ver28. Graphs were produced in Microsoft Excel 2016 and OriginPro Graphing and Analysis 2021.Primary trialsThe effect of chemical, concentration and time was analysed using a repeated measures three-way ANOVA for four sets of data gathered during the metamorphosis process: percentage of polyps to display tentacle migration, percentage of polyps to have medusa detach, percentage of polyps to have healthy swimming medusa detach, percentage survival of polyps that did not metamorphose. Percentage data was arcsine square root transformed prior to analysis. Mauchly’s Test of Sphericity indicated that the assumption of sphericity had been violated on all four sets of data and therefore, a Greenhouse–Geisser correction was used.Optimisation trialDifferences in the mean percentage of healthy medusa produced at different exposure times was analysed using ANOVA. Differences between means were elucidated using a Post hoc Tukey pairwise comparison test (Tukey HSD alpha 0.05). More

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    A noble extended stochastic logistic model for cell proliferation with density-dependent parameters

    Stability analysis of the deterministic modelSolving (left( x(t) times left( r_{p}x(t)^{(alpha )}left( 1-big (frac{x(t)}{K}big )^{beta }right) – nx(t)^{(delta )} right) right) =0), we obtain two stable and one unstable equilibrium points for the model. One stable equilibrium is trivial, i.e., (x(t)=0), another stable equilibrium point being the non-zero satisfying (left( r_{p}x(t)^{(alpha )}left( 1-big (frac{x(t)}{K}big )^{beta }right) – nx(t)^{(delta )} right) =0). Figure 1a shows three different equilibrium points of the model. In addition to the equilibrium, the model has two inflection points (Fig. 1a). At these inflection points the absolute growth rates are minimum and maximum. The density vs relative proliferation rate (RPR) profile of the model shows that the model can attain negative RPR for a positive cell density, suggesting that the model can portray the Allee phenomenon (Fig. 1b). Figure 1c,d portray the proliferation and decay phases, respectively through the model.Figure 1Growth dynamics of the proposed model: (a) Absolute proliferation rate (APR) profile considering (r_{p}=0.13), (K=1.43), (n=0.0095), (alpha =1.15), (beta =0.99) and (delta =0.2); (b) RPR profiles for different n and other same constant model parameters; (c) Cell population survive for (r_{p}=0.13), (K=1.43), (n=0.0095), (alpha =1.15), (beta =0.99) and (delta =0.2) with the initial cell density 0.1; (d) The population goes to extinction for the initial cell density 0.06 with the same constant parameters.Full size imageThe solution of the deterministic model finally provides two theorems.
    Theorem 1

    (x^{*}approx K -Kleft( frac{Big (beta r_{p}K^{alpha }+n delta K^{delta }Big )-sqrt{Big (beta r_{p}K^{alpha }+n delta K^{delta }Big )^{2}-2 left( 2 alpha beta r_{p}K^{alpha } +beta (beta -1)r_{p}K^{alpha }+delta (delta -1)nK^{delta } right) nK^{delta }}}{left( 2 alpha beta r_{p}K^{alpha } +beta (beta -1)r_{p}K^{alpha }+delta (delta -1)nK^{delta } right) }right)) is the conditional MSSCD for the intercellular-interaction-induced proliferative cells. The conditional threshold density for cell-proliferation upon interaction is (x^{*}=K -Kleft( frac{Big (beta r_{p}K^{alpha }+n delta K^{delta }Big )+sqrt{Big (beta r_{p}K^{alpha }+n delta K^{delta }Big )^{2}-2 left( 2 alpha beta r_{p}K^{alpha } +beta (beta -1)r_{p}K^{alpha }+delta (delta -1)nK^{delta } right) nK^{delta }}}{left( 2 alpha beta r_{p}K^{alpha } +beta (beta -1)r_{p}K^{alpha }+delta (delta -1)nK^{delta } right) }right)) (proof is in the supplementary information).
    Allee and cooperation models are the only extended logistic law other than our model to provide a threshold population size for growth or proliferation. Our proposed model is superior to the Allee and cooperation model as it can detect the conditional threshold cell density for proliferation and regulate the density by its different parameters. For example, One may reduce the conditional threshold density by either regulating the interaction between growth-inhibiting molecules and cells ((delta)) or reducing the inhibiting molecule concentration (n).The conditional MSSCD from Theorem 1 is lower than the carrying capacity of the conventional logistic model due to growth-inhibiting molecules; it provides the expected cell density during culture in a given environment. Theorem 1 also states the set of parameters to control the cell proliferation and get the desired density during such cell cultures. A further question arises knowing this set of parameters: which one of the parameters in the expression is crucial in terms of application purpose? Since the (r_{p}) is the constant proliferation rate for a given cell line, controlling the conditional MSSCD is not possible through (r_{p}). We simulate the distribution of conditional MSSCD for other parametric planes to answer this question. For this, we use the parameter values obtained from the data.

    Theorem 2

    The RPR is maximum at the cell density (x^{*}= K-Kleft( frac{r_{p}beta K^{alpha -1}+ndelta K^{delta -1}}{2r_{p}alpha beta K^{alpha -1}+r_{p}beta (beta -1)K^{alpha -1}+ndelta (delta -1)K^{delta -1}}right)) for the concave downward profile under the condition (r_{p}alpha (alpha -1){x^{*}}{}^{(alpha -2)}-frac{r_{p}}{K^{beta }}(alpha +beta )(alpha +beta -1){x^{*}}{}^{(alpha +beta -2)}-ndelta (delta -1){x^{*}}{}^{(delta -2)}n) (see the supplementary information). The cell population sustain with any positive initial cell density x(t) and try to stabilize at (x(t)= K(1-frac{n}{r_{p}})^frac{1}{beta }). Therefore, bimodality vanishes and unimodality is observed for the case (alpha =delta) (r_{p} >n). The RPR profile will be concave downward always with the maximum RPR value is at the inflection point (x(t)= K(frac{(r_{p}-n)alpha }{r_{p}(alpha +beta )})^frac{1}{beta }). The deterministic potential function in this case is (U(x)=-Big [(r_{p}-n)frac{x^{(alpha +2)}}{(alpha +2)}-frac{r_{p}}{K^{beta }}frac{x^{(alpha +beta +2)}}{(alpha +beta +2)} Big ]). The minima of this effective potential function will be at (x(t)= K(1-frac{n}{r_{p}})^frac{1}{beta }) which is the maximum stable cell density for (r_{p} >n).
    Parameter estimationThe density-RPR and time-density fitting to the scratch assay datasets show a lower RSS for our model than the logistic one for each of the three seeding conditions. The estimated parameters from the RPR fitting through the grid-search are in Table 2. Although the RSS for the RPR fitting of the seeding 2 is very low, the data itself is too scattered in both the upper and lower range for the small cell density. Therefore, there is a chance that regardless of the low RSS value, the fitting for seeding 2 may not reflect the actual estimates of the parameters with the bias in the data set (Fig. 2b). Nevertheless, the density-RPR fittings to the other two seeding density datasets do not suffer from bias (Fig. 2a,c).Table 2 Estimated model parameters from density-RPR fitting of our model.Full size table
    Figure 2Our proposed model best fitted the cell density-RPR datasets for all of the seeding conditions generated through the grid-search method.Full size image
    Jin et al.1 suggested that their two phase logistic model may share similarities with the Allee effect. However, they did not fit the Allee model stating seeding 2 and 3 were large enough seeding densities. We calculated the conditional threshold density, conditional MSSCD, density at the minimum and maximum RPR for the model from our estimated parameters (Table 3). The conditional threshold cell density calculated from our estimated parameters confirms that the smallest initial seeding density of the dataset was greater than the conditional threshold cell density.Table 3 Calculated cell densities from estimated parameters from our model fitting.Full size tableFigure 3 compares the portrayal of the data through our model with the fitting by Jin et al.1. The blue dashed line is the time-series fitting of the proposed model, and the red-colored line is the time-series fitting of the logistic model to the scratch assay data sets in the Fig. 3. The carrying capacity values are unexpectedly very high in the logistic fit, keeping the model near the exponential phase for the entire dataset. Thus the overall and two phase logistic fits are unrealistic compared to the highest cell density observed in the assay. Also, logistic fitting of the RPR profiles to the data after 18 h does not capture the whole scenario. The green solid and the violet dashed line represent the logistic time-density fit after and before 18 h density profiles respectively. The orange-colored lines in the Fig. 3 are the expected population density as per estimated parameters from the RPR fitting after 18 h data sets. Table 4 enlists all parameters for a comparison between logistic and our model fitting.Figure 3Time series solution of the proposed model and logistic law with comparative RSS for all three seeding conditions.Full size imageTable 4 Logistic model fitting with the Jin et al.1 estimates used in Fig. 3 with the specific colors.Full size tableTrends in cell densities under deterministic set upThe (r_{p}) is fixed for a cell line among all the determining parameters of the conditional MSSCD. n and K vary together with the culture media, flask, and environmental setup. On the other hand, the (alpha), (beta), and (delta) vary together with intercellular-interactions and cellular-interaction with growth-inhibitory molecules, which depend on the medium’s initial cell density per well and fluidity. We observe that the distribution of the conditional MSSCD depends more on the K than the n. There is a chance of overproliferation in the deterministic setup under low n but high K. The cells may die under high n. The cell density at maximum RPR also depends more on K than n (Fig. 4). So the cells should be cultured in the larger flask to achieve maximum proliferativeness.Figure 4The distribution of conditional MSSCD and cell density at maximum RPR in n-K parametric plane.Full size imageThe conditional MSSCD depends more on (beta) than (alpha) (Fig. 5a). The cells may tend to overproliferate under both high (alpha) and (beta). The conditional MSSCD does not exist for a high (delta) and low (beta) depending more on (delta) than (beta). The cells may overproliferate only under a high (beta) and low (delta) (Fig. 5b). The conditional MSSCD also depends more on (delta) than (alpha) showing mostly underproliferation of cells in the (delta ~-alpha) parametric plane. Therefore, the proliferation can be controlled via regulating the interaction between the growth-inhibitory molecules and cells followed by density-regulation through contact-inhibition and cell-cell cooperation (Fig. 5c).Figure 5The distribution of the conditional MSSCD in parametric plane of regulators in the growth law: (a) dependence of the conditional MSSCD on (alpha) and (beta) parameters; (b) dependence of the conditional MSSCD on (delta) and (beta) parameters; (c) dependence of the conditional MSSCD on (alpha) and (delta) parameters.Full size imageThe new cell fitness measure, i.e. cell density at maximum RPR depends more on the (alpha) than the (beta) (Fig. 6a). The cells achieve maximum RPR at a great cell density under the high value of these two parameters. Figure 6b,c suggest that cell density depends only a little on the (delta) under high (alpha) and (beta). Under the low value of these two regulators, a high (delta) always reduces the cell density attaining the maximum RPR, resulting a poor cell-fitness.Figure 6The distribution of cell density at maximum RPR in parametric plane of regulators in the growth law: (a) dependence on (alpha) and (beta) parameters; (b) dependence on (alpha) and (delta) parameters; (c) dependence on (delta) and (beta) parameters.Full size imageStochastic model analysisOur proposed stochastic model (3) can be compared with the general stratonovich stochastic differential equation (frac{dx}{dt}=f(x)+g_{1}(x)epsilon (t)+g_{2}(x)Gamma (t)). Comparing it with our proposed stochastic model we obtain (g_{1}(x)=-x^{delta +1}) and (g_{2}(x)=1). Using the help of47, we get noise induced drift (A(x)=r_{p}x^{alpha +1}left( 1-Big (frac{x}{K}Big )^{beta } right) -nx^{(delta +1)}+D(delta +1)x^{(2delta +1)}-lambda sqrt{DQ}(delta +1)x^{delta }) and noise induced diffusion coefficient (B(x)=Dx^{(2delta +2)}-2lambda sqrt{DQ}x^{(delta +1)}+Q). The cell density at long run can be obtained from the steady state probability density function (SSPDF). The analytical expression of the SSPDF is obtained from the Fokker-Planck equation. The Fokker-Planck equation is (frac{partial P(x, t)}{partial t} =- frac{partial big [ A(x) P(x, t)big ]}{partial x}+ frac{partial ^{2} big [B(x) P(x, t)big ]}{partial x^{2}}), where P(x,t) is the probability density function of the cell population at the time point t. Solving the Fokker-Planck equation we get the SSPDF as (P_{st} (x)= frac{N^{prime }}{B(x)} exp left( int _{x} frac{A(x^{prime })}{B(x^{prime })} dx^{prime }right)) with the normalizing constant (N^{prime }). The value of (N^{prime }) can be obtained from (int _{0}^{infty } P_{st} (x)dx=1).This SSPDF (P_{st} (x)) helps to understand the validity of the proposed stochastic model. Since the number of the data points is too low to fit the stochastic model to the data directly, validation of the stochastic model is challenging in this case. The dataset we used is a time series with 15 data points with three replicates only. An experiment must have many replicates to have a sample with a large sample size so that the SSPDF of cell densities obtained from theoretical findings can be validated with the real observation of cell densities at the steady state. Such datasets with many replicates are rare.So, we generate 2000 sample paths with the help of numerical simulation based on stochastic model 3. We use the parameter values estimated from the fittings of the deterministic model to the seeding condition 1, and we consider some particular values for the two noise intensities and correlation strength ((lambda)) to get a simulated dataset. To achieve the stationary state, we consider sufficiently large time points, and the cell densities at the final time point are used as the data set for the stationary state. We compare the frequency density of cell densities at steady-state of a simulated dataset of 2000 sample paths with the SSPDF obtained from the analytical solution. This comparison shows that the cell density distribution at the steady state matches the steady state probability density function obtained analytically (Fig. 7).In addition, we illustrated the time series generated with the help of stochastic model 3 through numerical technique (Fig. 8). We have plotted the time series data thus obtained for each of the three seeding conditions and in the same figure we also plotted the observed cell densities. The red dots (o) represent the original/experimental dataset of Jin et al.1. The blue dots ((*)) represent the simulated dataset obtained from the stochastic model. This Fig. 8 clarifies our claim that the proposed stochastic model is in good agreement with the actual observation.Figure 7The histogram shows the distribution of cell densities at steady state under additive and multiplicative noises. The blue curve is the SSPDF. The function SSPDF and the distribution of cell densities matches to each other.Full size imageFigure 8The red dots (o) in each sub-figures represent the experimental data of Jin et al.1. The blue dots ((*)) are obtained from the stochastic model (3) considering: (a) The seeding 1 estimated model parameters with (D= 0.002), (Q= 0.06) and (lambda = 0.4). (b) The seeding 2 estimated model parameters with (D= 0.01), (Q= 0.15) and (lambda = 0.6). (c) The seeding 3 estimated model parameters with (D= 0.002), (Q= 0.2) and (lambda = 0.4).Full size imageFigures 7 and 8 suggest that the stochastic model is valid. So the model can be further analyzed to meet the first objective. Differentiating (P_{st} (x)), we obtain (frac{dP_{st} (x)}{dx}=frac{N^{prime }}{[B(x)]^2} exp left( int frac{A(x)}{B(x)}dx right) left( A(x)-frac{dB(x)}{dx} right)) and (frac{d^{2}P_{st} (x)}{dx^{2}}= frac{N^{prime }}{[B(x)]^{2}}exp left( int frac{A(x)}{B(x)}dx right) left( frac{dA(x)}{dx}-frac{d^{2}B(x)}{dx^{2}} right) +frac{N^{prime }}{[B(x)]^{2}} left( A(x)-frac{dB(x)}{dx} right) exp left( int frac{A(x)}{B(x)}dx right) frac{A(x)}{B(x)}-frac{2}{[B(x)]^3}N^{prime } exp left( int frac{A(x)}{B(x)}dx right) left( A(x)-frac{dB(x)}{dx} right) frac{dB(x)}{dx}). At the extrema of the SSPDF, we must have (frac{dP_{st} (x)}{dx}=0) i.e. (left( A(x)-frac{dB(x)}{dx} right) =0).

    Theorem 3

    (x^{*}approx K-K left( frac{nK^{delta +1}+D(delta +1) K^{2delta +1}-lambda sqrt{DQ}(delta +1)K^{delta }}{beta r K^{alpha +1}+n(delta +1) K^{(delta +1)}+D(delta +1) (2delta +1)K^{(2delta +1)}-lambda sqrt{DQ}delta (delta +1)K^{delta }} right)) is the conditional MSSCD due to the correlated additive and multiplicative noises under the condition (r_{p}(alpha +1)x^{*}{}^{alpha }-frac{r_{p}}{K^{beta }}(alpha +beta +1)x^{*}{}^{(alpha +beta )} -n(delta +1)x^{*}{}^{delta }-D(delta +1)(2delta +1)x^{*}{}^{(2delta )}+lambda sqrt{Dalpha }delta (delta +1)x^{*}{}^{(delta -1)} < 0) (proof is in the supplementary information). Figure 9 visualizes the effect of noise strength and correlation strength on the conditional MSSCD. The conditional MSSCD increases with the additive noise strength (Q) and decreases with the multiplicative noise strength (D) when the other model parameters are fixed (Fig. 9a). There is a high chance of overproliferation for a low D and a high Q (Fig. 9a). Again, there is a high chance of extinction for the low Q and high D. The conditional MSSCD depends more on D than (lambda) (Fig. 9b), and more on (lambda) than Q (Fig. 9c). The conditional MSSCD increases with (lambda) and Q; there is a high chance of overproliferation for high (lambda) and Q. The extinction risk of cells from the culture increases with low (lambda) and Q.Figure 9The change in the conditional MSSCD value for different noise strengths and correlation strength using the parameters estimated for seeding 1: (a) the conditional MSSCD values in (D-Q) noise strength plane with highest correlation ((lambda =1)); (b) the conditional MSSCD values in (D-lambda) noise plane with (Q=0.01); (c) the conditional MSSCD values in (Q-lambda) noise plane with (D=0.01).Full size imageDue to the difficulty and complicated expression of the analytical expression of the SSPDF, we use numerical simulation to study the steady-state behavior in the long run under correlated noises. We draw a histogram of the cell densities based on 500 normal sample paths at the final time points. We use seeding 1 fitting estimates as the initial parameter values for this simulation. The cell population is stable and steady at either 0 cell density or at the conditional MSSCD. The distribution is symmetric around the conditional MSSCD for (lambda =1) (Fig. 10a). There is a loss in the symmetry for the decreasing (lambda). For (lambda =0.5), there is a mode at the zero states with another mode at conditional MSSCD (Fig. 10b). The histogram shows a bi-modality for low values of (lambda). The mode at the zero state is highest for (lambda =0) (Fig. 10c). Therefore, the extinction chance increases for zero noise correlation between the additive and the multiplicative noises.Figure 10Distribution of cell density for (r_{p}=0.13), (K=1.43), (n=0.0095), (alpha =1.15), (beta =0.99), (delta =0.2), (D=0.01), (Q=0.01), and variable correlation between additive and multiplicative noises: (a) (lambda =1), (b) (lambda =0.5) and (c) (lambda =0).Full size imageThe sustainability of the cell population depends on the strength of the two noises, like the correlation strength between them. For the zero strength multiplicative noise, the population has the mode at around the conditional MSSCD value (Fig. 11). Therefore, the population sustains in this case and tries to stabilize at the conditional MSSCD value. For (D=0.02), there is a bimodality, where the highest mode is at the zero cell density. For (D=0.05), we observe only one mode at (x=0). Therefore, with the increasing values of the multiplicative noise strengths (D), the chance of extinction increases for (lambda =0.5), (Q=0.01), and other constant model parameters for the seeding condition 1. Similar things happen for increasing Q values considering (D=0.01), (lambda =0.5), and other constant model parameters (Fig. 12).Figure 11Distribution of cell density for (r_{p}=0.13), (K=1.43), (n=0.0095), (alpha =1.15), (beta =0.99), (delta =0.2), (lambda =0.5), (Q=0.01), and variable strength of multiplicative noise: (a) (D=0.05), (b) (D=0.02) and (c) (D=0).Full size imageFigure 12Distribution of cell density for (r_{p}=0.13), (K=1.43), (n=0.0095), (alpha =1.15), (beta =0.99), (delta =0.2), (lambda =0.5), (D=0.01), and variable correlation between multiplicative noise: (a) (Q=0.05), (b) (Q=0.02) and (c) (Q=0).Full size image Remark 5 We have previously discussed the scenario for (alpha =delta) for deterministic case in Remark 4. It is important to understand the scenario under stochastic case too. For (alpha =delta) the proposed stochastic model 3 becomes (frac{dx(t)}{dt}=r_{p}x(t)^{(alpha +1)}left( 1-big (frac{x(t)}{K}big )^{beta }right) - nx(t)^{(alpha +1)}-x(t)^{(alpha +1)} epsilon (t)+ Gamma (t)). For this stochastic model (g_{1}(x)=-x^{alpha +1}) and (g_{2}(x)=1). We get, (A(x)=r_{p}x^{alpha +1}left( 1-Big (frac{x}{K}Big )^{beta } right) -nx^{(alpha +1)}+D(alpha +1)x^{(2alpha +1)}-lambda sqrt{DQ}(alpha +1)x^{alpha }) and (B(x)=Dx^{(2alpha +2)}-2lambda sqrt{DQ}x^{(alpha +1)}+Q). The extrema of the SPDF (big (x(t)=x^{*}big )) must satisfy the growth equation (r_{p}{x^{*}}^{alpha +1}-frac{r_{p}}{K^{beta }}(x^{*})^{alpha +beta +1}-n(x^{*})^{alpha +1}-D(alpha +1)(x^{*})^{2alpha +1}+lambda sqrt{D~Q}(alpha +1)(x^{*})^{alpha }=0). Therefore, for (alpha =delta) the conditional MSSCD is (x^{*}= K-Kfrac{nK^{(alpha +1)}+D(alpha +1)K^{(2alpha +1)}-lambda sqrt{DQ}(alpha +1)K^{alpha }}{beta r_{p}K^{(alpha +1)}+nK^{(alpha +1)}(alpha +1)+D(alpha +1)(2alpha +1)K^{(2alpha +1)}-alpha lambda sqrt{DQ}(alpha +1)K^{alpha }}) under the condition ((r_{p}-n)(alpha +1)(x^{*})^{alpha }-frac{r_{p}}{K^{beta }}(alpha +beta +1)(x^{*})^{(alpha + beta )}-(alpha +1)(2alpha +1)D(x^{*})^{2alpha }+lambda sqrt{DQ}(alpha +1)alpha (x^{*})^{(alpha -1)} More

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    Increasing salinity stress decreases the thermal tolerance of amphibian tadpoles in coastal areas of Taiwan

    Root, T. L. et al. Fingerprints of global warming on wild animals and plants. Nature 421, 57–60 (2003).ADS 
    CAS 
    Article 
    PubMed 

    Google Scholar 
    Meehl, G. A. et al. How much more global warming and sea level rise?. Science 307, 1769–1772 (2005).ADS 
    CAS 
    Article 
    PubMed 

    Google Scholar 
    Stocker, T. F. et al. (Cambridge University Press, 2013).Kopp, R. E. et al. Probabilistic 21st and 22nd century sea-level projections at a global network of tide-gauge sites. Earth’s Future 2, 383–406 (2014).ADS 
    Article 

    Google Scholar 
    Church, J. A. & White, N. J. A 20th century acceleration in global sea‐level rise. Geophys. Res. Lett. 33 (2006).Church, J. A. & White, N. J. Sea-level rise from the late 19th to the early 21st century. Surv. Geophys. 32, 585–602 (2011).ADS 
    Article 

    Google Scholar 
    Vermeer, M. & Rahmstorf, S. Global sea level linked to global temperature. Proc. Natl. Acad. Sci. 106, 21527–21532 (2009).ADS 
    CAS 
    PubMed Central 
    Article 
    PubMed 

    Google Scholar 
    Horton, B. P., Rahmstorf, S., Engelhart, S. E. & Kemp, A. C. Expert assessment of sea-level rise by AD 2100 and AD 2300. Quatern. Sci. Rev. 84, 1–6 (2014).ADS 
    Article 

    Google Scholar 
    Day, J. W., Pont, D., Hensel, P. F. & Ibañez, C. Impacts of sea-level rise on deltas in the Gulf of Mexico and the Mediterranean: The importance of pulsing events to sustainability. Estuaries 18, 636–647 (1995).CAS 
    Article 

    Google Scholar 
    Feagin, R. A., Sherman, D. J. & Grant, W. E. Coastal erosion, global sea-level rise, and the loss of sand dune plant habitats. Front. Ecol. Environ. 3, 359–364 (2005).Article 

    Google Scholar 
    Nicholls, R. J. Planning for the impacts of sea level rise. Oceanography 24, 144–157 (2011).Article 

    Google Scholar 
    Hinkel, J. et al. Coastal flood damage and adaptation costs under 21st century sea-level rise. Proc. Natl. Acad. Sci. 111, 3292–3297 (2014).ADS 
    CAS 
    PubMed Central 
    Article 
    PubMed 

    Google Scholar 
    Deutsch, C. A. et al. Impacts of climate warming on terrestrial ectotherms across latitude. Proc. Natl. Acad. Sci. 105, 6668–6672 (2008).ADS 
    CAS 
    PubMed Central 
    Article 
    PubMed 

    Google Scholar 
    Duarte, H. et al. Can amphibians take the heat? Vulnerability to climate warming in subtropical and temperate larval amphibian communities. Glob. Change Biol. 18, 412–421 (2012).ADS 
    Article 

    Google Scholar 
    Licht, P. & Brown, A. G. Behavioral thermoregulation and its role in the ecolgy of the red-bellied newt, Taricha rivularis. Ecology 48, 598–611 (1967).Article 

    Google Scholar 
    Feder, M. E. & Pough, F. H. Temperature selection by the red-backed salamander, Plethodon c. cinereus (Green) (Caudata: Plethodontidae). Comp. Biochem. Physiol. Part A Physiol. 50, 91–98 (1975).CAS 
    Article 

    Google Scholar 
    Keen, W. H. & Schroeder, E. E. Temperature selection and tolerance in three species of Ambystoma larvae. Copeia 1975, 523–530 (1975).Article 

    Google Scholar 
    Hoppe, D. M. Thermal tolerance in tadpoles of the chorus frog Pseudacris triseriata. Herpetologica. 318–321 (1978).Cupp Jr, P. V. Thermal tolerance of five salientian amphibians during development and metamorphosis. Herpetologica. 234–244 (1980).Howard, J. H., Wallace, R. L. & Stauffer, J. R. Critical thermal maxima in populations of Ambystoma macrodactylum from different elevations. J. Herpetol. 17, 400–402 (1983).Article 

    Google Scholar 
    Floyd, R. B. Ontogenetic change in the temperature tolerance of larval Bufo marinus (Anura: Bufonidae). Comp. Biochem. Physiol. A Physiol. 75, 267–271 (1983).Article 

    Google Scholar 
    Floyd, R. B. Effects of photoperiod and starvation on the temperature tolerance of larvae of the giant toad, Bufo marinus. Copeia 1985, 625–631 (1985).MathSciNet 
    Article 

    Google Scholar 
    Manis, M. L. & Claussen, D. L. Environmental and genetic influences on the thermal physiology of Rana sylvatica. J. Therm. Biol 11, 31–36 (1986).Article 

    Google Scholar 
    Layne, J., Claussen, D. & Manis, M. Effects of acclimation temperature, season, and time of day on the critical thermal maxima and minima of the crayfish Orconectes rusticus. J. Therm. Biol 12, 183–187 (1987).Article 

    Google Scholar 
    Lutterschmidt, W. I. & Hutchison, V. H. The critical thermal maximum: History and critique. Can. J. Zool. 75, 1561–1574 (1997).Article 

    Google Scholar 
    Simon, M. N., Ribeiro, P. L. & Navas, C. A. Upper thermal tolerance plasticity in tropical amphibian species from contrasting habitats: Implications for warming impact prediction. J. Therm. Biol 48, 36–44 (2015).Article 
    PubMed 

    Google Scholar 
    Boutilier, R., Donohoe, P., Tattersall, G. & West, T. Hypometabolic homeostasis in overwintering aquatic amphibians. J. Exp. Biol. 200, 387–400 (1997).CAS 
    Article 
    PubMed 

    Google Scholar 
    Shoemaker, V. & Nagy, K. A. Osmoregulation in amphibians and reptiles. Annu. Rev. Physiol. 39, 449–471 (1977).CAS 
    Article 
    PubMed 

    Google Scholar 
    Viertel, B. Salt tolerance of Rana temporaria: Spawning site selection and survival during embryonic development (Amphibia, Anura). Amphibia-Reptilia 20, 161–171 (1999).Article 

    Google Scholar 
    Wu, C.-S. & Kam, Y.-C. Thermal tolerance and thermoregulation by Taiwanese rhacophorid tadpoles (Buergeria japonica) living in geothermal hot springs and streams. Herpetologica 61, 35–46 (2005).Article 

    Google Scholar 
    Gomez-Mestre, I. & Tejedo, M. Local adaptation of an anuran amphibian to osmotically stressful environments. Evolution 57, 1889–1899 (2003).Article 
    PubMed 

    Google Scholar 
    Christy, M. T. & Dickman, C. R. Effects of salinity on tadpoles of the green and golden bell frog (Litoria aurea). Amphibia-Reptilia 23, 1–11 (2002).Article 

    Google Scholar 
    Wu, C.-S. & Kam, Y.-C. Effects of salinity on the survival, growth, development, and metamorphosis of Fejervarya limnocharis tadpoles living in brackish water. Zool. Sci. 26, 476–482 (2009).Article 

    Google Scholar 
    Wu, C. S., Yang, W. K., Lee, T. H., Gomez-Mestre, I. & Kam, Y. C. Salinity acclimation enhances salinity tolerance in tadpoles living in brackish water through increased Na+, K+-ATPase expression. J. Exp. Zool. A Ecol. Genet. Physiol. 321, 57–64 (2014).CAS 
    Article 
    PubMed 

    Google Scholar 
    Alexander, L. G., Lailvaux, S. P., Pechmann, J. H. & DeVries, P. J. Effects of salinity on early life stages of the Gulf Coast toad, Incilius nebulifer (Anura: Bufonidae). Copeia 2012, 106–114 (2012).Article 

    Google Scholar 
    Bernabò, I., Bonacci, A., Coscarelli, F., Tripepi, M. & Brunelli, E. Effects of salinity stress on Bufo balearicus and Bufo bufo tadpoles: Tolerance, morphological gill alterations and Na+/K+-ATPase localization. Aquat. Toxicol. 132, 119–133 (2013).Article 
    CAS 
    PubMed 

    Google Scholar 
    Kearney, B. D., Pell, R. J., Byrne, P. G. & Reina, R. D. Anuran larval developmental plasticity and survival in response to variable salinity of ecologically relevant timing and magnitude. J. Exp. Zool. A Ecol. Genet. Physiol. 321, 541–549 (2014).Article 
    PubMed 

    Google Scholar 
    Hsu, W. T., Wu, C. S., Hatch, K., Chang, Y. M. & Kam, Y. C. Full compensation of growth in salt-tolerant tadpoles after release from salinity stress. J. Zool. 304, 141–149 (2018).Article 

    Google Scholar 
    Hsu, W.-T. et al. Salinity acclimation affects survival and metamorphosis of crab-eating frog tadpoles. Herpetologica 68, 14–21 (2012).Article 

    Google Scholar 
    Lai, J.-C., Kam, Y.-C., Lin, H.-C. & Wu, C.-S. Enhanced salt tolerance of euryhaline tadpoles depends on increased Na+, K+-ATPase expression after salinity acclimation. Comp. Biochem. Physiol. A: Mol. Integr. Physiol. 227, 84–91 (2019).CAS 
    Article 

    Google Scholar 
    Brown, M. E. & Walls, S. C. Variation in salinity tolerance among larval anurans: Implications for community composition and the spread of an invasive, non-native species. Copeia 2013, 543–551 (2013).Article 

    Google Scholar 
    Balinsky, J. B. Adaptation of nitrogen metabolism to hyperosmotic environment in Amphibia. J. Exp. Zool. A Ecol. Genet. Physiol. 215, 335–350 (1981).CAS 

    Google Scholar 
    Duellman, W. & Trueb, L. Biology of Amphibians (John Hopkins University Press, 1994).
    Google Scholar 
    Alcala, A. C. Breeding behavior and early development of frogs of Negros, Philippine Islands. Copeia 1962, 679–726 (1962).Article 

    Google Scholar 
    Gordon, M. S. & Tucker, V. A. Osmotic regulation in the tadpoles of the crab-eating frog (Rana cancrivora). J. Exp. Biol. 42, 437–445 (1965).CAS 
    Article 

    Google Scholar 
    Dunson, W. A. Tolerance to high temperature and salinity by tadpoles of the Philippine frog, Rana cancrivora. Copeia 1977, 375–378 (1977).Article 

    Google Scholar 
    Uchiyama, M., Murakami, T., Wakasugi, C. & Yoshizawa, H. Structure of the kidney in the crab-eating frog, Rana cancrivora. J. Morphol. 204, 147–156 (1990).CAS 
    Article 
    PubMed 

    Google Scholar 
    Heo, K., Kim, Y. I., Bae, Y., Jang, Y. & Borzée, A. First report of Dryophytes japonicus tadpoles in saline environment. Russ. J. Herpetol. 26, 87–90 (2019).Article 

    Google Scholar 
    Jian, C. Y., Cheng, S. Y. & Chen, J. C. Temperature and salinity tolerances of yellowfin sea bream, Acanthopagrus latus, at different salinity and temperature levels. Aquac. Res. 34, 175–185 (2003).Article 

    Google Scholar 
    Sardella, B. A., Sanmarti, E. & Kültz, D. The acute temperature tolerance of green sturgeon (Acipenser medirostris) and the effect of environmental salinity. J. Exp. Zool. A Ecol. Genet. Physiol. 309, 477–483 (2008).Article 
    PubMed 

    Google Scholar 
    Everatt, M. J., Worland, M. R., Convey, P., Bale, J. S. & Hayward, S. A. The impact of salinity exposure on survival and temperature tolerance of the Antarctic collembolan Cryptopygus antarcticus. Physiol. Entomol. 38, 202–210 (2013).Article 

    Google Scholar 
    Kerby, J. L., Richards-Hrdlicka, K. L., Storfer, A. & Skelly, D. K. An examination of amphibian sensitivity to environmental contaminants: are amphibians poor canaries?. Ecol. Lett. 13, 60–67 (2010).Article 
    PubMed 

    Google Scholar 
    Chang, Y. M., Wu, C. S., Huang, Y. S., Sung, S. M. & Hwang, W. Occurrence and reproduction of anurans in brackish water in a coastal forest in Taiwan. Herpetol. Notes 9, 291–295 (2016).
    Google Scholar 
    Peng, T. R., Hsieh, Y. H. & Liu, T. S. Hydro chemical characteristics and salinization of groundwater in Yunlin area. J. Chin. Soil Water Conserv. 32, 173–189 (2005).
    Google Scholar 
    Gosner, K. L. A simplified table for staging anuran embryos and larvae with notes on identification. Herpetologica 16, 183–190 (1960).
    Google Scholar 
    Phillips, S. J., Anderson, R. P., Dudík, M., Schapire, R. E. & Blair, M. E. Opening the black box: An open-source release of Maxent. Ecography 40, 887–893 (2017).Article 

    Google Scholar 
    Hijmans, R. J., Cameron, S. E., Parra, J. L., Jones, P. G. & Jarvis, A. Very high resolution interpolated climate surfaces for global land areas. Int. J. Climatol. 25, 1965–1978 (2005).Article 

    Google Scholar 
    Groff, L. A., Marks, S. B. & Hayes, M. P. Using ecological niche models to direct rare amphibian surveys: A case study using the Oregon Spotted Frog (Rana pretiosa). Herpetol. Conserv. Biol. 9, 354–368 (2014).
    Google Scholar 
    Kumar, P. Assessment of impact of climate change on Rhododendrons in Sikkim Himalayas using Maxent modelling: limitations and challenges. Biodivers. Conserv. 21, 1251–1266 (2012).Article 

    Google Scholar 
    Pineda, E. & Lobo, J. M. Assessing the accuracy of species distribution models to predict amphibian species richness patterns. J. Anim. Ecol. 78, 182–190 (2009).Article 
    PubMed 

    Google Scholar 
    Yuan, H.-S., Wei, Y.-L. & Wang, X.-G. Maxent modeling for predicting the potential distribution of Sanghuang, an important group of medicinal fungi in China. Fungal Ecol. 17, 140–145 (2015).Article 

    Google Scholar 
    Chinathamby, K., Reina, R. D., Bailey, P. C. & Lees, B. K. Effects of salinity on the survival, growth and development of tadpoles of the brown tree frog, Litoria ewingii. Aust. J. Zool. 54, 97–105 (2006).Article 

    Google Scholar 
    Metcalfe, N. B. & Monaghan, P. Compensation for a bad start: Grow now, pay later?. Trends Ecol. Evol. 16, 254–260 (2001).Article 
    PubMed 

    Google Scholar 
    Metzger, D. C., Healy, T. M. & Schulte, P. M. Conserved effects of salinity acclimation on thermal tolerance and hsp70 expression in divergent populations of threespine stickleback (Gasterosteus aculeatus). J. Comp. Physiol. B. 186, 879–889 (2016).CAS 
    Article 
    PubMed 

    Google Scholar 
    Sanabria, E. et al. Effect of salinity on locomotor performance and thermal extremes of metamorphic Andean Toads (Rhinella spinulosa) from Monte Desert, Argentina. J. Therm. Biol. 74, 195–200 (2018).CAS 
    Article 
    PubMed 

    Google Scholar 
    Sokolova, I. M. Energy-limited tolerance to stress as a conceptual framework to integrate the effects of multiple stressors. Integr. Comp. Biol. 53, 597–608 (2013).Article 
    PubMed 

    Google Scholar 
    Kikawada, T. et al. Dehydration-induced expression of LEA proteins in an anhydrobiotic chironomid. Biochem. Biophys. Res. Commun. 348, 56–61 (2006).CAS 
    Article 
    PubMed 

    Google Scholar 
    Sanzo, D. & Hecnar, S. J. Effects of road de-icing salt (NaCl) on larval wood frogs (Rana sylvatica). Environ. Pollut. 140, 247–256 (2006).CAS 
    Article 
    PubMed 

    Google Scholar 
    Wood, L. & Welch, A. M. Assessment of interactive effects of elevated salinity and three pesticides on life history and behavior of southern toad (Anaxyrus terrestris) tadpoles. Environ. Toxicol. Chem. 34, 667–676 (2015).CAS 
    Article 
    PubMed 

    Google Scholar 
    Gomez-Mestre, I., Tejedo, M., Ramayo, E. & Estepa, J. Developmental alterations and osmoregulatory physiology of a larval anuran under osmotic stress. Physiol. Biochem. Zool. 77, 267–274 (2004).CAS 
    Article 
    PubMed 

    Google Scholar 
    Dent, J. N. Hormonal interaction in amphibian metamorphosis 1 2. Am. Zool. 28, 297–308 (1988).CAS 
    Article 

    Google Scholar 
    Bodensteiner, B. L. et al. Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?. J. Exp. Zool. Part A Ecol. Integr. Physiol. 335, 173–194 (2021).Article 

    Google Scholar 
    Rezende, E. L., Tejedo, M. & Santos, M. Estimating the adaptive potential of critical thermal limits: Methodological problems and evolutionary implications. Funct. Ecol. 25, 111–121 (2011).Article 

    Google Scholar 
    Mitchell, J. D., Hewitt, P. & Van Der Linde, T. D. K. Critical thermal limits and temperature tolerance in the harvester termite Hodotermes mossambicus (Hagen). J. Insect Physiol. 39, 523–528 (1993).Article 

    Google Scholar 
    Plummer, M. V., Williams, B. K., Skiver, M. M. & Carlyle, J. C. Effects of dehydration on the critical thermal maximum of the desert box turtle (Terrapene ornata luteola). J. Herpetol. 37, 747–751 (2003).Article 

    Google Scholar 
    Lee, S. et al. Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon. Comp. Biochem. Physiol. A Mol. Integr. Physiol. 198, 87–95 (2016).CAS 
    Article 
    PubMed 

    Google Scholar 
    Blaustein, A. R. & Wake, D. B. Declining amphibian populations: A global phenomenon?. Trends Ecol. Evol. 5, 203–204 (1990).Article 

    Google Scholar 
    Kiesecker, J. M., Blaustein, A. R. & Belden, L. K. Complex causes of amphibian population declines. Nature 410, 681 (2001).ADS 
    CAS 
    Article 
    PubMed 

    Google Scholar 
    Rohr, J. R. & Raffel, T. R. Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease. Proc. Natl. Acad. Sci. 107, 8269–8274 (2010).ADS 
    CAS 
    PubMed Central 
    Article 
    PubMed 

    Google Scholar 
    Pounds, J. A. et al. Widespread amphibian extinctions from epidemic disease driven by global warming. Nature 439, 161 (2006).ADS 
    CAS 
    Article 
    PubMed 

    Google Scholar 
    Skelly, D. & Freidenburg, L. Effects of beaver on the thermal biology of an amphibian. Ecol. Lett. 3, 483–486 (2000).Article 

    Google Scholar 
    Radchuk, V. et al. Adaptive responses of animals to climate change are most likely insufficient. Nat. Commun. 10, 1–14 (2019).CAS 
    Article 

    Google Scholar  More

  • in

    A bottom-up view of antimicrobial resistance transmission in developing countries

    Murray, C. J. et al. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. Lancet 399, 629–655 (2022).CAS 
    Article 

    Google Scholar 
    Nelson, R. E. et al. National estimates of healthcare costs associated with multidrug-resistant bacterial infections among hospitalized patients in the United States. Clin. Infect. Dis. 72, S17–S26 (2021).PubMed 
    Article 

    Google Scholar 
    Ludden, C. et al. One Health genomic surveillance of Escherichia coli demonstrates distinct lineages and mobile genetic elements in isolates from humans versus livestock. mBio 10, e02693-18 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Gouliouris, T. et al. Genomic surveillance of Enterococcus faecium reveals limited sharing of strains and resistance genes between livestock and humans in the United Kingdom. mBio 9, e01780-18 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Labar, A. S. et al. Regional dissemination of a trimethoprim-resistance gene cassette via a successful transposable element. PLoS ONE 7, e38142 (2012).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Lamikanra, A. et al. Rapid evolution of fluoroquinolone-resistant Escherichia coli in Nigeria is temporally associated with fluoroquinolone use. BMC Infect. Dis. 11, 312 (2011).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Kunhikannan, S. et al. Environmental hotspots for antibiotic resistance genes. MicrobiologyOpen 10, e1197 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Sulis, G., Sayood, S. & Gandra, S. Antimicrobial resistance in low- and middle-income countries: current status and future directions. Expert Rev. Anti Infect. Ther. 20, 147–160 (2022).CAS 
    PubMed 
    Article 

    Google Scholar 
    Okeke, I. N. & Nwoko, E. in Urban Crisis and Management in Africa: A Festschrift (eds Albert, I. O. & Mabogunje, A.) 125–148 (Pan-African Univ. Press, 2019).Doron, A. & Jeffrey, R. Waste of a Nation: Garbage and Growth in India (Harvard Univ. Press, 2018).Nadimpalli, M. L. et al. Urban informal settlements as hotspots of antimicrobial resistance and the need to curb environmental transmission. Nat. Microbiol. 5, 787–795 (2020).CAS 
    PubMed 
    Article 

    Google Scholar 
    Okeke, I. & Lamikanra, A. A study of the effect of the urban/rural divide on the incidence of antibiotic resistance in Escherichia coli. Biomed. Lett. 55, 91–97 (1997).
    Google Scholar 
    Aijuka, M., Charimba, G., Hugo, C. J. & Buys, E. M. Characterization of bacterial pathogens in rural and urban irrigation water. J. Water Health 13, 103–117 (2015).PubMed 
    Article 

    Google Scholar 
    Hendriksen, R. S. et al. Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage. Nat. Commun. 10, 1124 (2019).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Mahmud, Z. H. et al. Presence of virulence factors and antibiotic resistance among Escherichia coli strains isolated from human pit sludge. J. Infect. Dev. Ctries 13, 195–203 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Beukes, L. S., King, T. L. B. & Schmidt, S. Assessment of pit latrines in a peri-urban community in KwaZulu-Natal (South Africa) as a source of antibiotic resistant E. coli strains. Int. J. Hyg. Environ. Health 220, 1279–1284 (2017).PubMed 
    Article 

    Google Scholar 
    Zhang, H., Gao, Y. & Chang, W. Comparison of extended-spectrum β-lactamase-producing Escherichia coli isolates from drinking well water and pit latrine wastewater in a rural area of China. Biomed. Res. Int. 2016, 4343564 (2016).PubMed 
    PubMed Central 

    Google Scholar 
    Nji, E. et al. High prevalence of antibiotic resistance in commensal Escherichia coli from healthy human sources in community settings. Sci. Rep. 11, 3372 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Ramblière, L., Guillemot, D., Delarocque-Astagneau, E. & Huynh, B. T. Impact of mass and systematic antibiotic administration on antibiotic resistance in low- and middle-income countries? A systematic review. Int. J. Antimicrob. Agents 58, 106396 (2021).PubMed 
    Article 
    CAS 

    Google Scholar 
    Hlashwayo, D. F. et al. A systematic review and meta-analysis reveal that Campylobacter spp. and antibiotic resistance are widespread in humans in sub-Saharan Africa. PLoS ONE 16, e0245951 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Van Boeckel, T. P. et al. Global trends in antimicrobial resistance in animals in low- and middle-income countries. Science 365, eaaw1944 (2019).PubMed 
    Article 
    CAS 

    Google Scholar 
    Argudín, M. A. et al. Genotypes, exotoxin gene content, and antimicrobial resistance of Staphylococcus aureus strains recovered from foods and food handlers. Appl. Environ. Microbiol. 78, 2930–2935 (2012).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Sivagami, K., Vignesh, V. J., Srinivasan, R., Divyapriya, G. & Nambi, I. M. Antibiotic usage, residues and resistance genes from food animals to human and environment: an Indian scenario. J. Environ. Chem. Eng. 8, 102221 (2020).CAS 
    Article 

    Google Scholar 
    Wall, B. A. et al. Drivers, Dynamics and Epidemiology of Antimicrobial Resistance in Animal Production (FAO, 2016).Hassani, A. & Khan, G. Human–animal interaction and the emergence of SARS-CoV-2. JMIR Public Health Surveill. 6, e22117 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Madoshi, B. P. et al. Characterisation of commensal Escherichia coli isolated from apparently healthy cattle and their attendants in Tanzania. PLoS ONE 11, e0168160 (2016).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Guetiya Wadoum, R. E. et al. Abusive use of antibiotics in poultry farming in Cameroon and the public health implications. Br. Poult. Sci. 57, 483–493 (2016).CAS 
    PubMed 
    Article 

    Google Scholar 
    Rousham, E. K., Unicomb, L. & Islam, M. A. Human, animal and environmental contributors to antibiotic resistance in low-resource settings: integrating behavioural, epidemiological and One Health approaches. Proc. Biol. Sci. 285, 20180332 (2018).PubMed 
    PubMed Central 

    Google Scholar 
    Jibril, A. H., Okeke, I. N., Dalsgaard, A. & Olsen, J. E. Association between antimicrobial usage and resistance in Salmonella from poultry farms in Nigeria. BMC Vet. Res. 17, 234 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Tiseo, K., Huber, L., Gilbert, M., Robinson, T. P. & Van Boeckel, T. P. Global trends in antimicrobial use in food animals from 2017 to 2030. Antibiotics 9, 918 (2020).PubMed Central 
    Article 

    Google Scholar 
    Schar, D., Sommanustweechai, A., Laxminarayan, R. & Tangcharoensathien, V. Surveillance of antimicrobial consumption in animal production sectors of low- and middle-income countries: optimizing use and addressing antimicrobial resistance. PLoS Med. 15, e1002521 (2018).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Liu, Y. Y. et al. Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study. Lancet Infect. Dis. 16, 161–168 (2016).PubMed 
    Article 
    CAS 

    Google Scholar 
    Sun, J., Zhang, H., Liu, Y. H. & Feng, Y. Towards understanding MCR-like colistin resistance. Trends Microbiol. 26, 794–808 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Wang, C. et al. Identification of novel mobile colistin resistance gene mcr-10. Emerg. Microbes Infect. 9, 508–516 (2020).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    He, T. et al. Emergence of plasmid-mediated high-level tigecycline resistance genes in animals and humans. Nat. Microbiol. 4, 1450–1456 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Sun, C. et al. Plasmid-mediated tigecycline-resistant gene tet(X4) in Escherichia coli from food-producing animals, China, 2008–2018. Emerg. Microbes Infect. 8, 1524–1527 (2019).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Lowder, B. V. et al. Recent human-to-poultry host jump, adaptation, and pandemic spread of Staphylococcus aureus. Proc. Natl Acad. Sci. USA 106, 19545–19550 (2009).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Bachiri, T. et al. First report of the plasmid-mediated colistin resistance gene mcr-1 in Escherichia coli ST405 isolated from wildlife in Bejaia, Algeria. Microb. Drug Resist. 24, 890–895 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Roberts, M. C. et al. The human clone ST22 SCCmec IV methicillin-resistant Staphylococcus aureus isolated from swine herds and wild primates in Nepal: is man the common source? FEMS Microbiol. Ecol. 94, fiy052 (2018).PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Aliyu, A. B., Saleha, A. A., Jalila, A. & Zunita, Z. Risk factors and spatial distribution of extended spectrum β-lactamase-producing-Escherichia coli at retail poultry meat markets in Malaysia: a cross-sectional study. BMC Public Health 16, 699 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Alam, M. U. et al. Human exposure to antimicrobial resistance from poultry production: assessing hygiene and waste-disposal practices in Bangladesh. Int. J. Hyg. Environ. Health 222, 1068–1076 (2019).PubMed 
    Article 

    Google Scholar 
    Donado-Godoy, P. et al. Prevalence, risk factors, and antimicrobial resistance profiles of Salmonella from commercial broiler farms in two important poultry-producing regions of Colombia. J. Food Prot. 75, 874–883 (2012).CAS 
    PubMed 
    Article 

    Google Scholar 
    Moser, K. A. et al. The role of mobile genetic elements in the spread of antimicrobial-resistant Escherichia coli from chickens to humans in small-scale production poultry operations in rural Ecuador. Am. J. Epidemiol. 187, 558–567 (2018).PubMed 
    Article 

    Google Scholar 
    Songe, M. M., Hang’ombe, B. M., Knight-Jones, T. J. D. & Grace, D. Antimicrobial resistant enteropathogenic Escherichia coli and Salmonella spp. in houseflies infesting fish in food markets in Zambia. Int. J. Environ. Res. Public Health 14, (2017).Alves, T. S., Lara, G. H. B., Maluta, R. P., Ribeiro, M. G. & Leite, D. S. Carrier flies of multidrug-resistant Escherichia coli as potential dissemination agent in dairy farm environment. Sci. Total Environ. 633, 1345–1351 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Allen, H. K. et al. Call of the wild: antibiotic resistance genes in natural environments. Nat. Rev. Microbiol. 8, 251–259 (2010).CAS 
    PubMed 
    Article 

    Google Scholar 
    Hasan, B. et al. Antimicrobial drug–resistant Escherichia coli in wild birds and free-range poultry, Bangladesh. Emerg. Infect. Dis. 18, 2055–2058 (2012).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Blanco, G. Supplementary feeding as a source of multiresistant Salmonella in endangered Egyptian vultures. Transbound. Emerg. Dis. 65, 806–816 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Matias, C. A. R. et al. Frequency of zoonotic bacteria among illegally traded wild birds in Rio de Janeiro. Braz. J. Microbiol. 47, 882–888 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Brealey, J. C., Leitão, H. G., Hofstede, T., Kalthoff, D. C. & Guschanski, K. The oral microbiota of wild bears in Sweden reflects the history of antibiotic use by humans. Curr. Biol. 31, 4650–4658.e6 (2021).CAS 
    PubMed 
    Article 

    Google Scholar 
    Liu, C. M. et al. Escherichia coli ST131-H22 as a foodborne uropathogen. mBio 9, e00470-18 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Randad, P. R. et al. Transmission of antimicrobial-resistant Staphylococcus aureus clonal complex 9 between pigs and humans, United States. Emerg. Infect. Dis. 27, 740–748 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Jørgensen, S. L. et al. Diversity and population overlap between avian and human Escherichia coli belonging to sequence type 95. mSphere 4, e00333-18 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Ludden, C. et al. A One Health study of the genetic relatedness of Klebsiella pneumoniae and their mobile elements in the east of England. Clin. Infect. Dis. 70, 219–226 (2020).PubMed 
    Article 

    Google Scholar 
    Thorpe, H. et al. One Health or Three? Transmission modelling of Klebsiella isolates reveals ecological barriers to transmission between humans, animals and the environment. Preprint at bioRxiv https://doi.org/10.1101/2021.08.05.455249 (2021).Ingham, A. C. et al. Dynamics of the human nasal microbiota and Staphylococcus aureus cc398 carriage in pig truck drivers across one workweek. Appl. Environ. Microbiol. 87, e0122521 (2021).PubMed 
    Article 

    Google Scholar 
    Hickman, R. A. et al. Exploring the antibiotic resistance burden in livestock, livestock handlers and their non-livestock handling contacts: a One Health perspective. Front. Microbiol. 12, 65161 (2021).Article 

    Google Scholar 
    Okeke, I. N. African biomedical scientists and the promises of ‘big science’. Can J. Afr. Stud. https://doi.org/10.1080/00083968.2016.1266677 (2017).Nadimpalli, M. L. & Pickering, A. J. A call for global monitoring of WASH in wet markets. Lancet Planet. Health 4, e439–e440 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Grace, D. & Little, P. Informal trade in livestock and livestock products. Rev. Sci. Tech. 39, 183–192 (2020).CAS 
    PubMed 
    Article 

    Google Scholar 
    Caudell, M. A. et al. Towards a bottom-up understanding of antimicrobial use and resistance on the farm: a knowledge, attitudes, and practices survey across livestock systems in five African countries. PLoS ONE 15, e0220274 (2020).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Adekanye, U. O. et al. Knowledge, attitudes and practices of veterinarians towards antimicrobial resistance and stewardship in Nigeria. Antibiotics 9, 453 (2020).CAS 
    PubMed Central 
    Article 

    Google Scholar 
    Mangesho, P. E. et al. ‘We are doctors’: drivers of animal health practices among Maasai pastoralists and implications for antimicrobial use and antimicrobial resistance. Prev. Vet. Med. 188, 105266 (2021).PubMed 
    Article 

    Google Scholar 
    Essack, S. Water, sanitation and hygiene in national action plans for antimicrobial resistance. Bull. World Health Organ. 99, 606–608 (2021).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Aarestrup, F. M. et al. Effect of abolishment of the use of antimicrobial agents for growth promotion on occurrence of antimicrobial resistance in fecal enterococci from food animals in Denmark. Antimicrob. Agents Chemother. 45, 2054–2059 (2001).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Funtowicz, S. & Ravetz, J. in Handbook of Transdisciplinary Research (eds Hadorn, G. H. et al.) 361–368 (Springer, 2008); https://doi.org/10.1007/978-1-4020-6699-3Theuretzbacher, U., Outterson, K., Engel, A. & Karlén, A. The global preclinical antibacterial pipeline. Nat. Rev. Microbiol. 185, 275–285 (2019).
    Google Scholar 
    Lacotte, Y., Årdal, C. & Ploy, M. C. Infection prevention and control research priorities: what do we need to combat healthcare-associated infections and antimicrobial resistance? Results of a narrative literature review and survey analysis. Antimicrob. Resist. Infect. Control 9, 142 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Kennedy, D. A. & Read, A. F. Why the evolution of vaccine resistance is less of a concern than the evolution of drug resistance. Proc. Natl Acad. Sci. USA 115, 12878 (2018).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Vekemans, J. et al. Leveraging vaccines to reduce antibiotic use and prevent antimicrobial resistance: a World Health Organization action framework. Clin. Infect. Dis. 73, E1011–E1017 (2021).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Micoli, F., Bagnoli, F., Rappuoli, R. & Serruto, D. The role of vaccines in combatting antimicrobial resistance. Nat. Rev. Microbiol. 195, 287–302 (2021).Article 
    CAS 

    Google Scholar 
    Massella, E. et al. Antimicrobial resistance profile and ExPEC virulence potential in commensal Escherichia coli of multiple sources. Antibiotics 10, 351 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Huttner, A. et al. Safety, immunogenicity, and preliminary clinical efficacy of a vaccine against extraintestinal pathogenic Escherichia coli in women with a history of recurrent urinary tract infection: a randomised, single-blind, placebo-controlled phase 1b trial. Lancet Infect. Dis. 17, 528–537 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Frenck, R. W. et al. Safety and immunogenicity of a vaccine for extra-intestinal pathogenic Escherichia coli (ESTELLA): a phase 2 randomised controlled trial. Lancet Infect. Dis. 19, 631–640 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Patel, R. & Fang, F. C. Diagnostic stewardship: opportunity for a laboratory-infectious diseases partnership. Clin. Infect. Dis. 67, 799–801 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Okeke, I. N. Divining Without Seeds: The Case for Strengthening Laboratory Medicine in Africa (Cornell Univ. Press, 2011).Loosli, K., Davis, A., Muwonge, A. & Lembo, T. Addressing antimicrobial resistance by improving access and quality of care—a review of the literature from East Africa. PLoS Negl. Trop. Dis. 15, e0009529 (2021).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Chokshi, A., Sifri, Z., Cennimo, D. & Horng, H. Global contributors to antibiotic resistance. J. Glob. Infect. Dis. 11, 36–42 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Adedapo, A. D. & Akunne, O. O. Patterns of antimicrobials prescribed to patients admitted to a tertiary care hospital: a prescription quality audit. Cureus 13, e15896 (2021).PubMed 
    PubMed Central 

    Google Scholar 
    Kumarasamy, K. K. et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect. Dis. 10, 597–602 (2010).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Davenport, M. et al. New and developing diagnostic technologies for urinary tract infections. Nat. Rev. Urol. 14, 298–310 (2017).Article 

    Google Scholar 
    van Dongen, J. E. et al. Point-of-care CRISPR/Cas nucleic acid detection: recent advances, challenges and opportunities. Biosens. Bioelectron. 166, 112445 (2020).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Nielsen, T. B. et al. Monoclonal antibody therapy against Acinetobacter baumannii. Infect. Immun. 89, e0016221 (2021).PubMed 
    Article 

    Google Scholar 
    Dwivedi, P., Narvi, S. S. & Tewari, R. P. Application of polymer nanocomposites in the nanomedicine landscape: envisaging strategies to combat implant associated infections. J. Appl. Biomater. Funct. Mater. 11, 129–142 (2013).
    Google Scholar 
    Song, M., Wu, D., Hu, Y., Luo, H. & Li, G. Characterization of an Enterococcus faecalis bacteriophage vB_EfaM_LG1 and its synergistic effect with antibiotic. Front. Cell. Infect. Microbiol. 11, 636 (2021).
    Google Scholar 
    Dhama, K. et al. Growth promoters and novel feed additives improving poultry production and health, bioactive principles and beneficial applications: the trends and advances—a review. Int. J. Pharmacol. 10, 129–159 (2014).CAS 
    Article 

    Google Scholar 
    Vieco-Saiz, N. et al. Benefits and inputs from lactic acid bacteria and their bacteriocins as alternatives to antibiotic growth promoters during food-animal production. Front. Microbiol. 10, 57 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Ng, W. K. & Koh, C. B. The utilization and mode of action of organic acids in the feeds of cultured aquatic animals. Rev. Aquac. 9, 342–368 (2017).Article 

    Google Scholar 
    Mattioli, G. A. et al. Effects of parenteral supplementation with minerals and vitamins on oxidative stress and humoral immune response of weaning calves. Animals 10, 1298 (2020).PubMed Central 
    Article 

    Google Scholar 
    Mwangi, S., Timmons, J., Fitz-Coy, S. & Parveen, S. Characterization of Clostridium perfringens recovered from broiler chicken affected by necrotic enteritis. Poult. Sci. 98, 128–135 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Prendergast, A. J. et al. Putting the ‘A’ into WaSH: a call for integrated management of water, animals, sanitation, and hygiene. Lancet Planet. Health 3, e336–e337 (2019).PubMed 
    Article 

    Google Scholar 
    Martinelli, M. et al. Probiotics’ efficacy in paediatric diseases: which is the evidence? A critical review on behalf of the Italian Society of Pediatrics. Ital. J. Pediatr. 46, 104 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Rasko, D. A. & Sperandio, V. Anti-virulence strategies to combat bacteria-mediated disease. Nat. Rev. Drug Discov. 9, 117–128 (2010).CAS 
    PubMed 
    Article 

    Google Scholar 
    Rodrigues, M., McBride, S. W., Hullahalli, K., Palmer, K. L. & Duerkop, B. A. Conjugative delivery of CRISPR–Cas9 for the selective depletion of antibiotic-resistant enterococci. Antimicrob. Agents Chemother. 63, e01454-19 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Casu, B., Arya, T., Bessette, B. & Baron, C. Fragment-based screening identifies novel targets for inhibitors of conjugative transfer of antimicrobial resistance by plasmid pKM101. Sci. Rep. 7, 14907 (2017).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Denyer Willis, L. & Chandler, C. Quick fix for care, productivity, hygiene and inequality: reframing the entrenched problem of antibiotic overuse. BMJ Glob. Health 4, e001590 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Wilkinson, A., Ebata, A. & Macgregor, H. Interventions to reduce antibiotic prescribing in LMICs: a scoping review of evidence from human and animal health systems. Antibiotics 8, 2 (2018).Torres, N. F., Chibi, B., Middleton, L. E., Solomon, V. P. & Mashamba-Thompson, T. P. Evidence of factors influencing self-medication with antibiotics in low and middle-income countries: a systematic scoping review. Public Health 168, 92–101 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Potgieter, N., Banda, N. T., Becker, P. J. & Traore-Hoffman, A. N. WASH infrastructure and practices in primary health care clinics in the rural Vhembe District municipality in South Africa. BMC Fam. Pract. 22, 8 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Humphreys, G. Reinventing the toilet for 2.5 billion in need. Bull. World Health Organ. 92, 470–471 (2014).PubMed 
    Article 

    Google Scholar 
    Yam, P., Fales, D., Jemison, J., Gillum, M. & Bernstein, M. Implementation of an antimicrobial stewardship program in a rural hospital. Am. J. Health Syst. Pharm. 69, 1142–1148 (2012).PubMed 
    Article 

    Google Scholar 
    Sartelli, M. et al. Antibiotic use in low and middle-income countries and the challenges of antimicrobial resistance in surgery. Antibiotics 9, 497 (2020).PubMed Central 
    Article 

    Google Scholar 
    Büdel, T. et al. On the island of Zanzibar people in the community are frequently colonized with the same MDR Enterobacterales found in poultry and retailed chicken meat. J. Antimicrob. Chemother. 75, 2432–2441 (2020).PubMed 
    Article 
    CAS 

    Google Scholar 
    Finch, M. J., Morris, J. G., Kaviti, J., Kagwanja, W. & Levine, M. M. Epidemiology of antimicrobial resistant cholera in Kenya and East Africa. Am. J. Trop. Med. Hyg. 39, 484–490 (1988).CAS 
    PubMed 
    Article 

    Google Scholar 
    Mutreja, A. et al. Evidence for several waves of global transmission in the seventh cholera pandemic. Nature 477, 462–465 (2011).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Weill, F. X. et al. Genomic history of the seventh pandemic of cholera in Africa. Science 358, 785–789 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Opintan, J. A., Newman, M. J., Nsiah-Poodoh, O. A. & Okeke, I. N. Vibrio cholerae O1 from Accra, Ghana carrying a class 2 integron and the SXT element. J. Antimicrob. Chemother. 62, 929–933 (2008).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Garbern, S. C. et al. Clinical and socio-environmental determinants of multidrug-resistant Vibrio cholerae 01 in older children and adults in Bangladesh. Int. J. Infect. Dis. 105, 436–441 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Mintz, E. D. & Guerrant, R. L. A lion in our village—the unconscionable tragedy of cholera in Africa. N. Engl. J. Med. https://doi.org/10.1056/NEJMp0810559 (2009).Gibani, M. M. et al. The impact of vaccination and prior exposure on stool shedding of Salmonella typhi and Salmonella paratyphi in 6 controlled human infection studies. Clin. Infect. Dis. 68, 1265–1273 (2019).CAS 
    PubMed 
    Article 

    Google Scholar  More

  • in

    Changes in plant biodiversity facets of rocky outcrops and their surrounding rangelands across precipitation and soil gradients

    Larson, D. W., Matthes, U. & Kelly, P. E. Cliff Ecology (Cambridge University Press, 2000).Book 

    Google Scholar 
    Cooper, A. Plant species coexistence in cliff habitats. J. Biogeogr. 24, 483–494 (1997).Article 

    Google Scholar 
    Davis, P. H. Cliff vegetation in the eastern Mediterranean. J. Ecol. 39, 63–93 (1951).Article 

    Google Scholar 
    Snogerup, S. Evolutionary and plant geographical aspects of chasmophytic communities. In Plant life of South-West Asia (eds Davis, P. H. et al.) 157–170 (Bot. Soc. Edinb, 1971).
    Google Scholar 
    Baskin, J. M. & Baskin, C. C. Endemism in rock outcrop plant communities of unglaciated eastern United States: An evaluation of the roles of the edaphic, genetic and light factors. J. Biogeogr. 15, 829–840 (1988).Article 

    Google Scholar 
    Medina, B. M. O. & Fernandes, G. W. The potential of natural regeneration of rocky outcrop vegetation on rupestrian field soils in Serra do Cipo, Brazil. Braz. J. Bot. 30, 665–678 (2007).Article 

    Google Scholar 
    Alves, R. J. V., Cardin, L. & Kropf, M. S. Angiosperm disjunction “Campos Rupestres-Restingas”: Are-evaluation. Acta Bot. Bras. 2, 675–685 (2007).Article 

    Google Scholar 
    Harley, R. M. Introduction. In Flora of the Pico das Almas, Chapada Diamantina, Bahia, Brazil (eds Stannard, B. L., Harvey, Y. B. & Harley, R. M) 1–42 (Royal Botanic Gardens, 1995).Hubbell, S. P. Neutral theory in ecology and the evolution of ecological equivalence. Ecology 87, 1387–1398 (2006).PubMed 
    Article 

    Google Scholar 
    Conceição, A. A., Pirani, J. R. & Meirelles, S. T. Floristics, structure and soil of insular vegetation in four quartzite-sandstone outcrops of “Chapada Diamantina”, Northeast Brazil. Rev. Bras. Bot. 30, 641–656 (2007).Article 

    Google Scholar 
    Le Stradic, S., Buisson, E. & Wilson, F. G. Vegetation composition and structure of some Neotropical mountain grasslands in Brazil. J Mt Sci 12:864–77. An. Acad. Bras. Ciênc. 87(4), 2097–2110 (2015).Article 
    CAS 

    Google Scholar 
    Nunes, J. A. et al. Soil–vegetation relationships on a banded ironstone ‘island’, Carajás Plateau, Brazilian Eastern Amazonia. An. Acad. Bras. Cienc. 87(4), 2097–2110 (2015).CAS 
    PubMed 
    Article 

    Google Scholar 
    Silva, W. A. Gradiente vegetacional e pedológico em complexo rupestre de quartzito no Quadrilátero Ferrífero, Minas Gerais, Brasil. MSc Thesis. (Universidade Federal de Viçosa, 2013).Vincent, R. C. & Meguro, M. Influence of soil properties on the abundance of plant species in ferruginous rocky soils vegetation, southeastern Brazil. Braz. J. Bot. 31, 377–388 (2008).Article 

    Google Scholar 
    Porembski, S. Tropical inselbergs: Habitat types, adaptive strategies and diversity patterns. Rev. Bras. de Bot. 30, 579–586 (2007).Article 

    Google Scholar 
    De Paula, L. F. A., Forzza, R. C., Neri, A. V., Bueno, M. L. & Porembski, S. Sugar Loaf Land in south-eastern Brazil: A center of diversity for mat-forming bromeliads on inselbergs. Bot. J. Linn. Soc. 181, 459–476 (2016).Article 

    Google Scholar 
    Rezende, M. G., Elias, R. C. L., Salimena, F. R. G. & Neto, L. M. Flora vascular da Serra da Pedra Branca, Caldas, Minas Gerais e relações florísticas com áreas de altitude da Região Sudeste do Brasil. Biota Neotrop. 13, 201–224 (2013).Article 

    Google Scholar 
    Sarthou, C., Villiers, J. F. & Ponge, J. F. Shrub vegetation on tropical granitic inselbergs in French Guiana. J. Veg. Sci. 14, 645–652 (2003).Article 

    Google Scholar 
    Tinti, B. V. et al. Plant diversity on granite/gneiss rock outcrop at Pedra do Pato, Serra do Brigadeiro State Park, Brazil. Check List 11, 1780 (2015).Article 

    Google Scholar 
    Barbara, T., Martinelli, G., Fay, M. F., Mayo, S. J. & Lexer, C. Population differentiation and species cohesion in two closely related plants adapted to neotropical high-altitude “inselbergs”, Alcantarea imperialis and Alcantarea geniculata (Bromeliaceae). Mol. Ecol. 16, 1981–1992 (2007).CAS 
    PubMed 
    Article 

    Google Scholar 
    Boisselier-Dubayle, M. C., Leblois, R., Samadi, S., Lambourdière, J. & Sarthou, C. Genetic structure of the xerophilous bromeliad Pitcairnia geyskesii on inselbergs in French Guiana—A test of the forest refuge hypothesis. Ecography 33, 175–184 (2010).Article 

    Google Scholar 
    Domingues, R. et al. Genetic variability of an endangered Bromeliaceae species (Pitcairnia albiflos) from the Brazilian Atlantic rainforest. Genet. Mol. Res. 10, 2482–2491 (2011).CAS 
    PubMed 
    Article 

    Google Scholar 
    Hmeljevski, K. V. et al. Conservation assessment of an extremely restricted bromeliad highlights the need for population-based conservation on granitic inselbergs of the Brazilian Atlantic Forest. Flora Morpho. Distribut. Funct. Ecolo. Plants. 209, 250–259 (2014).Article 

    Google Scholar 
    Palma-Silva, C. et al. Sympatric bromeliad species (Pitcairnia spp.) facilitate tests of mechanisms involved in species cohesion and reproductive isolation in Neotropical inselbergs. Mol. Ecol. 20, 3185–3201 (2011).CAS 
    PubMed 
    Article 

    Google Scholar 
    Gomes, P. & Alves, M. Floristic diversity of two crystalline rocky outcrops in the Brazilian northeast semi-arid region. Rev. Bras. Bot. 33(4), 661–676 (2010).Article 

    Google Scholar 
    Nunes, J. A., Villa, P. M., Neri, A. V., Silva, W. A. & Schaefer, C. E. G. R. Seasonality drives herbaceous community beta diversity in lithologically different rocky outcrops in Brazil. Plant. Ecol. Evol. 153(2), 208–218 (2020).Article 

    Google Scholar 
    Speziale, K. L. & Ezcurra, C. The role of outcrops in the diversity of Patagonian vegetation: Relicts of glacial palaeofloras?. Flora Morphol. Distrib. Funct. Ecol. Plant. 207, 141–149 (2012).
    Google Scholar 
    Speziale, K. L., Ruggiero, A. & Ezcurra, C. Plant species richness–environment relationships across the Subantarctic-Patagonian transition zone. J. Biogeogr. 37, 449–464 (2010).Article 

    Google Scholar 
    Yates, C. J. et al. High species diversity and turnover in granite inselberg floras highlight the need for a conservation strategy protecting many outcrops. Ecol. Evol. 9, 7660–7675 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Gaston, K. J. Geographic range limits: Achieving synthesis. Proc. R. Soc. B Biol. Sci. 276, 1395–1406 (2009).Article 

    Google Scholar 
    McGann, T. D. How insular are ecological ‘islands’? An example from the granitic outcrops of the New England Batholith of Australia. Proc. R. Soc. Queensland. 110, 1–13 (2002).
    Google Scholar 
    Parmentier, I., Stévart, T. & Hardy, O. J. The inselberg flora of Atlantic Central Africa. I. Determinants of species assemblages. J. Biogeogr. 32, 685–696 (2005).Article 

    Google Scholar 
    Changwe, K. & Balkwill, K. Floristics of the Dunbar Valley serpentinite site, Songimvelo Game Reserve, South Africa. Bot. J. Linn. Soc. 143, 271–285 (2003).Article 

    Google Scholar 
    Clarke, P. J. Habitat islands in fire-prone vegetation: Do landscape features influence community composition?. J. Biogeogr. 29, 677–684 (2002).Article 

    Google Scholar 
    De Bello, F., Leps, J. & Sebastia, M. T. Variations in species and functional plant diversity along climatic and grazing gradients. Ecography 29(6), 801–810 (2006).Article 

    Google Scholar 
    Porembski, S., Martinelli, G., Ohlemüller, R. & Barthlott, W. Diversity and ecology of saxicolous vegetation mats on inselbergs in the Brazilian Atlantic rainforest. Divers. Distrib. 4, 107–119 (1998).Article 

    Google Scholar 
    Porembski, S., Szarzynski, J., Mund, J. P. & Barthlott, W. Biodiversity and vegetation of small-sized inselbergs in a West African rain forest (Taï, Ivory Coast). J. Biogeogr. 23, 47–55 (1996).Article 

    Google Scholar 
    Rahmanian, S. et al. Effects of livestock grazing on soil, plant functional diversity, and ecological traits vary between regions with different climates in northeastern Iran. Ecol. Evol. 9, 8225–8237 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Speziale, K. L. & Ezcurra, C. Patterns of alien plant invasions in northwestern Patagonia, Argentina. J. Arid Environ. 75, 890–897 (2011).ADS 
    Article 

    Google Scholar 
    Qian, H., Chen, S. H. & Zhang, J. L. Disentangling environmental and spatial effects on phylogenetic structure of angiosperm tree communities in China. Sci. Rep. 7, 5864 (2017).ADS 
    Article 
    CAS 

    Google Scholar 
    Farzam, M. & Ejtehadi, H. Effects of drought and canopy facilitation on plant diversity and abundance in a semiarid mountainous rangeland. J. Plant. Ecol. 10(4), 626–633 (2016).
    Google Scholar 
    Heino, J. & Tolonen, K. T. Ecological drivers of multiple facets of beta diversity in a lentic macroinvertebrate metacommunity. Limnol. Oceanogr. 62, 2431–2444. https://doi.org/10.1002/lno.10577 (2017).ADS 
    Article 

    Google Scholar 
    Miranda, J. D., Armas, C., Padilla, F. M. & Pugnaire, F. I. Climatic change and rainfall patterns: Effects on semi-arid plant communities of the Iberian Southeast. J. Arid. Environ. 75, 1302–1309 (2011).ADS 
    Article 

    Google Scholar 
    Pashirzad, M., Ejtehadi, H., Vaezi, J. & Shefferson, R. P. Multiple processes at different spatial scales determine beta diversity patterns in a mountainous semi-arid rangeland of Khorassan-Kopet Dagh floristic province, NE Iran. Plant. Ecol. 220(9), 829–844 (2019).Article 

    Google Scholar 
    Victorero, L., Robert, K., Robinson, L. F., Taylor, M. L. & Huvenne, V. A. I. Species replacement dominates megabenthos beta diversity in a remote seamount setting. Sci. Rep. 8, 4152 (2018).ADS 
    PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Deil, U. Rock communities in tropical Arabia. Flora et Vegetation Mundi 9, 175–187 (1991).
    Google Scholar 
    Dimopoulos, P., Sýkora, K. V., Mucina, L. & Georgiadis, T. The high-rank syntaxa of the rock-cliff and scree vegetation of the mainland Greece and Crete. Folia Geobot. 32, 313–334 (1997).Article 

    Google Scholar 
    Hein, P., Kürschner, H. & Parolly, G. Phytosociological studies on high mountain plant communities of the Taurus Mountains (Turkey) 2. Rock communities. Phytocoenologia 28, 465–563 (1998).Article 

    Google Scholar 
    Nowak, A., Nowak, S., Nobis, M. & Nobis, A. Vegetation of rock clefts and ledges in the Pamir Alai Mts, Tajikistan (Middle Asia). Cent. Eur. J. Biol. 9, 444–460 (2014).
    Google Scholar 
    Urbis, A. & Blazyca, B. Rock vascular plant species of the Kraków-Częstochowa, Uplands. Thaiszia J. Bot. 21, 207–214 (2011).
    Google Scholar 
    Wiser, S. K., Peet, R. K. & White, P. S. High-elevation rock outcrop vegetation of the Southern Appalachian Mountains. J. Veg. Sci. 7, 703–722 (1996).Article 

    Google Scholar 
    Cadotte, M. W. Experimental evidence that evolutionarily diverse assemblages result in higher productivity. PNAS 110(22), 8996–9000 (2013).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Swenson, G.N. Functional and Phylogenetic Ecology in R (Use R!) Kindle Edition (2014).Cadotte, M. W. & Davies, P. R. Why phylogenies do not always predict ecological differences. Ecol. Monogr. 87(4), 535–551 (2016).Article 

    Google Scholar 
    De Bello, F., LepŠ, J. A. N. & Sebastià, M. T. Predictive value of plant traits to grazing along a climatic gradient in the Mediterranean. J. Appl. Ecol. 42(5), 824–833 (2005).Article 

    Google Scholar 
    Funk, J. et al. Revisiting the Holy Grail: Using plant functional traits to understand ecologica processes. Biol. Rev. 92(2), 1156–1173 (2017).PubMed 
    Article 

    Google Scholar 
    Lavorel, S. & Garnier, É. Predicting changes in community composition and ecosystem functioning from plant traits: Revisiting the Holy Grail. Funct. Ecol. 16(5), 545–556 (2002).Article 

    Google Scholar 
    Violle, C. et al. Let the concept of trait be functional!. Oikos 116, 882–892 (2007).Article 

    Google Scholar 
    Zheng, S., Li, W., Lan, Z., Ren, H. & Wang, K. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity. Sci. Rep. 5, 18163 (2015).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Gillison, A. N. Plant functional types and traits at the community, ecosystem and world level. In Vegetation Ecology (eds van der Maarel, E. & Franklin, J.) 347–386 (Wiley, 2013).Chapter 

    Google Scholar 
    Loreau, M. Biodiversity and ecosystem functioning: Recent theoretical advances. Oikos 91, 3–17 (2000).Article 

    Google Scholar 
    Akhani, H., Djamali, M., Ghorbanalizadeh, A. & Ramezani, E. Plant biodiversity of Hyrcanian relict forests, N Iran: An overview of the flora, vegetation, paleoecology and conservation. Pak. J. Bot. 42, 231–258 (2010).
    Google Scholar 
    Hamzehee, B. et al. Phytosociological survey of remnant Alnus glutinosa ssp. barbata communities in the lowland Caspian forests of northern Iran. Pytocoenologia. 38, 117–132 (2008).Article 

    Google Scholar 
    Moradi, H. et al. Elevational gradient and vegetation-environmental relationships in the central Hyrcanian forests of northern Iran. Nord. J. Bot. 34, 1–14 (2016).Article 

    Google Scholar 
    Naqinezhad, A., Esmailpoor, A. & Jafari, N. A new record of Pyrola minor (Pyrolaceae) for the flora of Iran as well as a description of its surrounding habitats. Taxon. Biosyst. 22, 71–80 (2015).
    Google Scholar 
    Naqinezhad, A., Zare-Maivan, H. & Gholizadeh, H. A floristic survey of the Hyrcanian forests in Northern Iran, using two lowland-mountain transects. J. For. Res. 26, 187–199 (2015).CAS 
    Article 

    Google Scholar 
    Sagheb-Talebi, K., Sajedi, T. & Pourhashemi, M. Forests of Iran (Springer Sci, 2014).Book 

    Google Scholar 
    Siadati, S. et al. Botanical diversity of Hyrcanian forests; a case study of a transect in the Kheyrud protected lowland mountain forests in northern Iran. Phytotaxa 7, 1–18 (2010).Article 

    Google Scholar 
    Akhani, H. & Ziegler, H. Photosynthetic pathways and habitats of grasses in Golestan National Park (NE Iran), with an emphasis on the C 4-grass dominated rock communities. Phytocoenologia 32, 455–501 (2002).Article 

    Google Scholar 
    Akhani, H., Mahdavi, P., Noroozi, J. & Zarrinpour, V. Vegetation patterns of the Irano-Turanian steppe along a 3,000 m altitudinal gradient in the Alborz Mountains of Northern Iran. Folia Geobot. 48, 229–255 (2013).Article 

    Google Scholar 
    Klein, J. C. The altitudinal vegetation Alborez The Central (Iran) between the Iranian-Turanian and Euro-Siberian regions (French) (Institut Français de Recherche en Iran, 2001).
    Google Scholar 
    Noroozi, J. Case study: High Mountain Regions in Iran 255–260. of Chapter 7 (Endemism in mainland regions-case studies). In Endemism in Vascular plants. Plant. Veg. (ed Hobohm, C.) 9. (Springer, 2014).Noroozi, J., Akhani, H. & Willner, W. Phytosociological and ecological study of the high alpine vegetation of Tuchal Mountains (Central Alborz, Iran). Phytocoenologia 40, 293–321 (2010).Article 

    Google Scholar 
    Do Carmo, F. F. & Jacobi, C. M. Diversity and plant trait-soil relationships among rock outcrops in the Brazilian Atlantic rainforest. Plant Soil. 403, 7–20 (2015).Article 
    CAS 

    Google Scholar 
    Cavender-Bares, J., Kozak, K. H., Fine, P. V. A. & Kembel, S. The merging of community ecology and phylogenetic biology. Ecol Lett. 12, 693–715 (2009).PubMed 
    Article 

    Google Scholar 
    Heydari, M., Poorbabaei, H., Esmailzadeh, O., Salehi, A. & EshaghiRad, J. Indicator plant species in monitoring forest soil conditions using logistic regression model in Zagros Oak (Quercus brantii var. persica) forest ecosystems. Ilam city. J. Plant Res. 27(5), 811–828 (2014).
    Google Scholar 
    Speziale, K. L. & Ezcurra, C. Rock outcrops as potential biodiversity refugia under climate change in North Patagonia. Plant Ecol. Diver. 8, 353–361 (2014).Article 

    Google Scholar 
    Rahmanian, S. et al. Effects of livestock grazing on plant species diversity vary along a climatic gradient in northeastern Iran. Appl. Veg. Sci. 23, 551–561 (2020).Article 

    Google Scholar 
    Huston, M. A. Biological Diversity: The Coexistence of Species in Changing Landscape (Cambridge University, 1994).
    Google Scholar 
    Mason, N. W., Mouillot, D. & Lee, W. G. Functional richness, functional evenness and functional divergence: The primary components of functional diversity. Oikos 111, 112–118 (2005).Article 

    Google Scholar 
    Stubbs, W. J. & Wilson, J. B. Evidence for limiting similarity in a sand dune community. J. Ecol. 92, 557567 (2004).Article 

    Google Scholar 
    Stanisci, A. et al. Functional composition and diversity of leaf traits in subalpine versus alpine vegetation in the Apennines. Ann. Bot. Comp. plants. 12, plaa004 (2020).CAS 

    Google Scholar 
    Chesson, P. et al. Resource pulses, species interactions, and diversity maintenance in arid and semi-arid environments. Oecologia 141, 236–253 (2004).ADS 
    PubMed 
    Article 

    Google Scholar 
    Rosbakh, S. et al. Contrasting effects of extreme drought and snowmelt patterns on mountain plants along an elevation gradient. Front. Plant Sci. 8, 1478 (2017).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Korner, C. Alpine Treelines: Functional Ecology of the Global High Elevation tree Limits (Springer Sci. & Business Media, 2012).Book 

    Google Scholar 
    Reich, P. B. et al. Generality of leaf trait relationships: A test across six biomes. Ecology 80, 1955–1969 (1999).Article 

    Google Scholar 
    Westoby, M., Falster, D. S., Moles, A. T., Vesk, P. A. & Wright, I. J. Plant ecological strategies: Some leading dimensions of variation between species. Ann. Rev. Ecol. Syst. 33, 125–159 (2002).Article 

    Google Scholar 
    Hautier, Y., Niklaus, P. A. & Hector, A. Competition for light causes plant biodiversity loss after eutrophication. Science 324, 636–638 (2009).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    De Bello, F. D. et al. Hierarchical effects of environmental filters on the functional structure of plant communities: A case study in the French Alps. Ecography 36, 393–402 (2013).Article 

    Google Scholar 
    Korner, C., Neumayer, M., Menendez-Riedl, S. P. & Smeets-Scheel, A. Functional morphology of mountain plants. Flora 182, 353–383 (1989).Article 

    Google Scholar 
    Rosbakh, S., Römermann, C. & Poschlod, P. Specific leaf area correlates with temperature new evidence of trait variation at the population, species and community levels. Alp. Bot. 125, 79–86 (2015).Article 

    Google Scholar 
    Ordonez, J. C. et al. Global study of relationships between leaf traits, climate and soil measures of nutrient fertility. Glob. Ecol. Biogeogr. 18, 137–149 (2009).Article 

    Google Scholar 
    Li, W. et al. Community-weighted mean traits but not functional diversity determine the changes in soil properties during wetland drying on the Tibetan Plateau. Solid Earth. 8, 137–147 (2017).ADS 
    Article 

    Google Scholar 
    Bardgett, R. D., Mommer, L. & De Vries, F. T. Going underground: Root traits as drivers of ecosystem processes. Trends Ecol. Evol. 29, 692–699 (2014).PubMed 
    Article 

    Google Scholar 
    Lane, D. R., Coffin, D. P. & Lauenroth, W. K. Effects of soil texture and precipitation on above-ground net primary productivity and vegetation structure across the Central Grassland region of the United States. J. Veg. Sci. 9, 239–250 (1998).Article 

    Google Scholar 
    Noy-Meir, I. Multivariate analysis of the semi-arid vegetation of southern Australia. II. Vegetation catenae an environmental gradients. Aust. J. Bot. 22, 40–115 (1973).
    Google Scholar 
    Moura, M. R., Villalobos, F., Costa, G. C. & Garcia, P. C. A. Disentangling the role of climate, topography and vegetation in species richness gradients. PLoS ONE 11(3), 0152468 (2016).Article 
    CAS 

    Google Scholar 
    Neri, A. V. et al. Soil and altitude drives diversity and functioning of Brazilian Páramos (Campo de Altitude). J. plant. Ecol. 10(5), 771–779 (2016).
    Google Scholar 
    Benites, V. M., Schaefer, C. E. G. R., Simas, F. N. B., Santos, H. G. & Mendonca, B. A. F. Soils associated to rock outcrops in the Brazilian mountain ranges Mantiqueira and Espinhaço. Rev. Bras. Bot. 30, 569–577 (2007).Article 

    Google Scholar 
    Flynn, D. F. B. et al. Loss of functional diversity under land use intensification across multiple taxa. Ecol. Lett. 12, 22–33 (2009).PubMed 
    Article 

    Google Scholar 
    Zuo, X. A. et al. Testing associations of plant functional diversity with along a restoration gradient of sandy grassland. Front. Plant. Sci. 7, 1–11 (2016).ADS 
    Article 

    Google Scholar 
    Myers-Smith, I. H. et al. Shrub expansion in tundra ecosystems: Dynamics, impacts and research priorities. Environ. Res. Lett. 6, 045509 (2011).ADS 
    Article 

    Google Scholar 
    Vankoughnett, M. R. & Grogan, P. Nitrogen isotope tracer acquisition in low and tall birch tundra plant communities: A 2-year test of the snow–shrub hypothesis. Biogeochemistry 118, 291–306 (2014).CAS 
    Article 

    Google Scholar 
    Pescador, D. S., de Bello, F., Valladares, F. & Escudero, A. Plant trait variation along an altitudinal gradient in Mediterranean high mountain grasslands: Controlling the species turnover effect. PLoS ONE 10, e0118876 (2015).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Pescador, D. S., Sierra-Almeida, A., Torres, P. J. & Escudero, A. Summer freezing resistance: A critical filter for plant community assemblies in Mediterranean high mountains. Front. Plant. Sci. 7, 194 (2016).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Heydarnejad, S. & Ranjbar, A. Investigation of the effect of salinity stress on growth characteristic and ion accumulation in plants. J. Desert Ecos. Eng. 3(4), 1–10 (2013).
    Google Scholar 
    Perez-Harguindeguy, N. et al. New handbook for standardized measurement of plant functional traits worldwide. Aust. J. Bot. 61, 167–234 (2013).Article 

    Google Scholar 
    Cornelissen, J. H. C. et al. A handbook of protocols for standardised and easy measurement of plant functional traits worldwide. Aust. J. Bot. 51, 335–380 (2003).Article 

    Google Scholar 
    Raunkiaer, C. The Life Forms of Plants and Statistical Plant Geography (Oxford University Press, 1934).
    Google Scholar 
    Gee, G. W. & Bauder, J. W. Particle size analysis. In Methods of Soil Analysis. Part 1, 2nd ed. (ed Klute, A.) Agronomy Monographs, Vol. 9, 383–409 (Am. Soc. Agr., 1986).Bremner, J. M. In Nitrogen-Total Methods of Soil Analysis. (eds Sparks, D. L.) Soil Sci Soc Am J. 1085–1122 (Am Soc Agr. Inc, 1996).Walkley, A. & Black, I. A. An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Sci. 37, 29–38 (1934).ADS 
    CAS 
    Article 

    Google Scholar 
    Nelson, D. W. & Sommers, L. Total carbon, organic carbon, and organic matter 1. Methods of soil analysis. Part 2. Chemical and microbi‐ological properties, (methodsofsoilan2), 539–579 (1982).Miller, R. H. & Keeney, D. R. Methods of soil analysis, 2nd ed. In Part 2. Chemical and Microbiological Properties (eds Page, A. L. et al.) 1–129 (ASA, SSSA, 1982).
    Google Scholar 
    Food and Agriculture Organization-FAO. Management of gypsiferous soils. Soil Bulletin, 62, (FAO, 1990).Chao, A. et al. Rarefaction and extrapolation with Hill numbers: A framework for sampling and estimation in species diversity studies. Ecol. Monogr. 84, 45–67 (2014).Article 

    Google Scholar 
    Shipley, B., Vile, D. & Garnier, É. from plant traits to plant communities: A statistica mechanistic approach to biodiversity. Science 314(5800), 812–814 (2006).ADS 
    MathSciNet 
    CAS 
    PubMed 
    MATH 
    Article 

    Google Scholar 
    Zhu, J., Jiang, L. & Zhang, Y. Relationships between functional diversity and aboveground biomass production in the Northern Tibetan alpine grasslands. Sci. Rep. 6, 34105 (2016).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Laliberte, E. & Legendre, P. A distance-based framework for measuring functional diversity from multiple traits. Ecology 91(1), 299–305 (2010).PubMed 
    Article 

    Google Scholar 
    Wheeler, D. & Tiefelsdorf, M. Multicollinearity and correlation among local regression coefficients in geographically weighted regression. J. Geogr. Syst. 7, 161–187 (2005).Article 

    Google Scholar 
    Fox, J. & Weisberg, S. A review of: an R companion to applied regression, second edition. J. Biopharm. Stat. 22, 418–419 (2011).
    Google Scholar 
    Brien, R. M. A caution regarding rules of thumb for variance inflation factors. Qual. Quant. 41, 673–690 (2007).Article 

    Google Scholar 
    Dray, S., Legendre, P. & Blanchet, F. G. packfor: forward selection with permutation (Canoco p. 46). (2011) http://R-Forge.R-project.org/projects/sedar (Accessed 7 Nov 2016).Blanchet, F. G., Legendre, P. & Borcard, D. Forward selection of explanatory variables. Ecology 89, 2623–2632 (2008).PubMed 
    Article 

    Google Scholar 
    Oksanen, J. et al. vegan: Community Ecology Package (2017).Wickham, H. et al. Ggplot2: Elegant Graphics for Data Analysis 2nd edn. (Springer International Publishing, 2016).MATH 
    Book 

    Google Scholar  More

  • in

    Incorporation of machine learning and deep neural network approaches into a remote sensing-integrated crop model for the simulation of rice growth

    Jones, J. W. et al. The DSSAT cropping system model. Eur. J. Agron. 18, 235–265 (2003).Article 

    Google Scholar 
    van Diepen, C. A., Wolf, J., van Keulen, H. & Rappoldt, C. WOFOST: a simulation model of crop production. Soil Use Manag. 5, 16–24 (1989).Article 

    Google Scholar 
    Cao, J. et al. Integrating multi-source data for rice yield prediction across China using machine learning and deep learning approaches. Agric. For. Meteorol. 297, 108275 (2021).ADS 
    Article 

    Google Scholar 
    Khanal, S., Kushal, K. C., Fulton, J. P., Shearer, S. & Ozkan, E. Remote sensing in agriculture—accomplishments, limitations, and opportunities. Remote Sens. 12, 3783 (2020).ADS 
    Article 

    Google Scholar 
    Maas, S. J. Parameterised model of gramineous crop growth: II. within-season simulation calibration. Agron. J. 85, 354–358 (1993).Article 

    Google Scholar 
    Nguyen, V., Jeong, S., Ko, J., Ng, C. & Yeom, J. Mathematical integration of remotely-sensed information into a crop modelling process for mapping crop productivity. Remote Sens. 11, 2131 (2019).Article 

    Google Scholar 
    Huang, J. et al. Assimilation of remote sensing into crop growth models: current status and perspectives. Agric. For. Meteorol. 276–277, 107609 (2019).ADS 
    Article 

    Google Scholar 
    Jin, X. et al. A review of data assimilation of remote sensing and crop models. Eur. J. Agron. 92, 141–152 (2018).Article 

    Google Scholar 
    Shawon, A. R. et al. Assessment of a proximal sensing-integrated crop model for simulation of soybean growth and yield. Remote Sens. 12, 410 (2020).ADS 
    Article 

    Google Scholar 
    Shawon, A. R. et al. Two-dimensional simulation of barley growth and yield using a model integrated with remote-controlled aerial imagery. Remote Sens. 12, 3766 (2020).ADS 
    Article 

    Google Scholar 
    Shin, T. et al. Simulation of wheat productivity using a model integrated with proximal and remotely controlled aerial sensing information. Front. Plant Sci. https://doi.org/10.3389/fpls.2021.649660 (2021).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    Huang, J. et al. Assimilating a synthetic Kalman filter leaf area index series into the WOFOST model to improve regional winter wheat yield estimation. Agric. For. Meteorol. 216, 188–202 (2016).ADS 
    Article 

    Google Scholar 
    Khaki, S., Wang, L. & Archontoulis, S. V. A CNN-RNN framework for crop yield prediction. Front. Plant Sci. https://doi.org/10.3389/fpls.2019.01750 (2020).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    Kim, N. et al. An artificial intelligence approach to prediction of corn yields under extreme weather conditions using satellite and meteorological data. Appl. Sci. 10, 3785 (2020).CAS 
    Article 

    Google Scholar 
    Kumar, P. et al. Comprehensive evaluation of soil moisture retrieval models under different crop cover types using C-band synthetic aperture radar data. Geocarto Int. 34, 1022–1041 (2019).Article 

    Google Scholar 
    Everingham, Y., Sexton, J., Skocaj, D. & Inman-Bamber, G. Accurate prediction of sugarcane yield using a random forest algorithm. Agron. Sustain. Dev. 36, 27 (2016).Article 

    Google Scholar 
    Feng, P., Wang, B., Li Liu, D., Waters, C. & Yu, Q. Incorporating machine learning with biophysical model can improve the evaluation of climate extremes impacts on wheat yield in south-eastern Australia. Agric. For. Meteorol. 275, 100–113 (2019).ADS 
    Article 

    Google Scholar 
    Shahhosseini, M., Hu, G., Huber, I. & Archontoulis, S. V. Coupling machine learning and crop modeling improves crop yield prediction in the US Corn Belt. Sci. Rep. 11, 1606 (2021).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Cai, Y. et al. Detecting in-season crop nitrogen stress of corn for field trials using UAV- and CubeSat-based multispectral sensing. IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens. 12, 5153–5166 (2019).ADS 
    Article 

    Google Scholar 
    van Klompenburg, T., Kassahun, A. & Catal, C. Crop yield prediction using machine learning: a systematic literature review. Comput. Electron. Agric. 177, 105709 (2020).Article 

    Google Scholar 
    Kamilaris, A. & Prenafeta-Boldú, F. X. Deep learning in agriculture: a survey. Comput. Electron. Agric. 147, 70–90 (2018).Article 

    Google Scholar 
    Bui, D. T., Tsangaratos, P., Nguyen, V.-T., Liem, N. V. & Trinh, P. T. Comparing the prediction performance of a deep learning neural network model with conventional machine learning models in landslide susceptibility assessment. CATENA 188, 104426 (2020).Article 

    Google Scholar 
    Sahoo, A. K., Pradhan, C. & Das, H. Performance evaluation of different machine learning methods and deep-learning based convolutional neural network for health decision making. In Nature Inspired Computing for Data Science (eds Rout, M. et al.) (Springer International Publishing, 2020).
    Google Scholar 
    Jeong, S. et al. Development of Variable Threshold Models for detection of irrigated paddy rice fields and irrigation timing in heterogeneous land cover. Agric. Water Manag. 115, 83–91 (2012).Article 

    Google Scholar 
    Peng, D., Huete, A. R., Huang, J., Wang, F. & Sun, H. Detection and estimation of mixed paddy rice cropping patterns with MODIS data. Int. J. Appl. Earth Obs. Geoinf. 13, 13–23 (2011).ADS 

    Google Scholar 
    Jeong, S., Ko, J. & Yeom, J.-M. Nationwide projection of rice yield using a crop model integrated with geostationary satellite imagery: a case study in South Korea. Remote Sens. 10, 1665 (2018).ADS 
    Article 

    Google Scholar 
    Xiao, X. et al. Mapping paddy rice agriculture in South and Southeast Asia using multi-temporal MODIS images. Remote Sens. Environ. 100, 95–113 (2006).ADS 
    Article 

    Google Scholar 
    Ozdogan, M. & Gutman, G. A new methodology to map irrigated areas using multi-temporal MODIS and ancillary data: an application example in the continental US. Remote Sens. Environ. 112, 3520–3537 (2008).ADS 
    Article 

    Google Scholar 
    Yeom, J.-M., Jeong, S., Deo, R. C. & Ko, J. Mapping rice area and yield in northeastern Asia by incorporating a crop model with dense vegetation index profiles from a geostationary satellite. GISci. Remote Sens. 58, 1–27 (2021).Article 

    Google Scholar 
    Yeom, J.-M. et al. Monitoring paddy productivity in North Korea employing geostationary satellite images integrated with GRAMI-rice model. Sci. Rep. 8, 16121 (2018).ADS 
    PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Jeong, S., Ko, J., Choi, J., Xue, W. & Yeom, J.-M. Application of an unmanned aerial system for monitoring paddy productivity using the GRAMI-rice model. Int. J. Remote Sens. 39, 2441–2462 (2018).Article 

    Google Scholar 
    Jeong, S. et al. Geographical variations in gross primary production and evapotranspiration of paddy rice in the Korean Peninsula. Sci. Total Environ. 714, 136632 (2020).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Roger, P., Vermote, E. & Ray, J. MODIS Surface Reflectance User’s Guide. Collection 6 (2015).Scharlemann, J. P. W. et al. Global data for ecology and epidemiology: a novel algorithm for temporal Fourier processing MODIS data. PLoS ONE 3, e1408 (2008).ADS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Pede, T. & Mountrakis, G. An empirical comparison of interpolation methods for MODIS 8-day land surface temperature composites across the conterminous Unites States. ISPRS J. Photogramm. Remote Sens. 142, 137–150 (2018).ADS 
    Article 

    Google Scholar 
    Kilibarda, M. et al. Spatio-temporal interpolation of daily temperatures for global land areas at 1 km resolution. J. Geophys. Res. Atmos. 119, 2294–2313 (2014).ADS 
    Article 

    Google Scholar 
    Nunez, M. The development of a satellite-based insolation model for the tropical western Pacific Ocean. Int. J. Climatol. 13, 607–627 (1993).Article 

    Google Scholar 
    Otkin, J. A., Anderson, M. C., Mecikalski, J. R. & Diak, G. R. Validation of GOES-based insolation estimates using data from the U.S. Climate reference network. J. Hydrometeorol. 6, 460–475 (2005).ADS 
    Article 

    Google Scholar 
    Pinker, R. & Laszlo, I. Modeling surface solar irradiance for satellite applications on a global scale. J. Appl. Meteorol. 31, 194–211 (1992).ADS 
    Article 

    Google Scholar 
    Kawamura, H., Tanahashi, S. & Takahashi, T. Estimation of insolation over the Pacific Ocean off the Sanriku coast. J. Oceanogr. 54, 457–464 (1998).Article 

    Google Scholar 
    Yeom, J.-M., Seo, Y.-K., Kim, D.-S. & Han, K.-S. Solar radiation received by slopes using COMS imagery, a physically based radiation model, and GLOBE. J. Sens. 2016, 1–15 (2016).Article 

    Google Scholar 
    Yeom, J.-M., Han, K.-S. & Kim, J.-J. Evaluation on penetration rate of cloud for incoming solar radiation using geostationary satellite data. Asia-Pac. J. Atmos. Sci. 48, 115–123 (2012).ADS 
    Article 

    Google Scholar 
    Kawai, Y. & Kawamura, H. Validation and improvement of satellite-derived surface solar radiation over the Northwestern Pacific Ocean. J. Oceanogr. 61, 79–89 (2005).Article 

    Google Scholar 
    Tanahashi, S., Kawamura, H., Matsuura, T., Takahashi, T. & Yusa, H. A system to distribute satellite incident solar radiation in real-time. Remote Sens. Environ. 75, 412–422 (2001).ADS 
    Article 

    Google Scholar 
    Elbern, H., Schmidt, H., Talagrand, O. & Ebel, A. 4D-variational data assimilation with an adjoint air quality model for emission analysis. Environ. Model. Softw. 15, 539–548 (2000).Article 

    Google Scholar 
    Press, W. H., Teukolsky, S. A., Vetterling, W. T. & Flannery, B. P. Numerical Recipes: The Art of Scientific Computing (Cambridge University Press, 1992).MATH 

    Google Scholar 
    Ko, J. et al. Simulation and mapping of rice growth and yield based on remote sensing. J. Appl. Remote Sens. 9, 096067 (2015).Article 

    Google Scholar 
    Emami Javanmard, M., Ghaderi, S. F. & Hoseinzadeh, M. Data mining with 12 machine learning algorithms for predict costs and carbon dioxide emission in integrated energy-water optimization model in buildings. Energy Convers. Manag. 238, 114153 (2021).CAS 
    Article 

    Google Scholar 
    Diebold, F. X. & Shin, M. Machine learning for regularized survey forecast combination: partially-egalitarian LASSO and its derivatives. Int. J. Forecast. 35, 1679–1691 (2019).Article 

    Google Scholar 
    Khosla, E., Dharavath, R. & Priya, R. Crop yield prediction using aggregated rainfall-based modular artificial neural networks and support vector regression. Environ. Dev. Sustain. 22, 5687–5708 (2020).Article 

    Google Scholar 
    Wang, S., Azzari, G. & Lobell, D. B. Crop type mapping without field-level labels: random forest transfer and unsupervised clustering techniques. Remote Sens. Environ. 222, 303–317 (2019).ADS 
    Article 

    Google Scholar 
    Ustuner, M. & Balik, S. F. Polarimetric target decompositions and light gradient boosting machine for crop classification: a comparative evaluation. ISPRS Int. J. Geo Inf. 8, 97 (2019).Article 

    Google Scholar 
    Jeong, S., Ko, J. & Yeom, J.-M. Predicting rice yield at pixel scale through synthetic use of crop and deep learning models with satellite data in South and North Korea. Sci. Total Environ. 802, 149726 (2022).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Nash, J. E. & Sutcliffe, J. V. River flow forecasting through conceptual models part I: a discussion of principles. J. Hydrol. 10, 282–290 (1970).ADS 
    Article 

    Google Scholar  More

  • in

    Municipal biowaste treatment plants contribute to the contamination of the environment with residues of biodegradable plastics with putative higher persistence potential

    Choice of biowaste treatment plants and sample identifiersCompost samples were collected from four central municipal biowaste treatment plants (denominated as #1 to #4) in Baden-Wurttemberg, Germany (Table 1). All plants used a state-of-the-art two-stage biowaste treatment process comprising of (a) anaerobic digestion/biogas production and (b) subsequent composting of the solid digestate to produce a high-quality mature compost sold for direct use as fertilizer in agriculture. The composts were regularly analyzed by an independent laboratory for quality and residual contamination and consistently fulfilled the quality requirements of the label RAL-GZ 251 Gütezeichen Kompost of the German Bundesgütegemeinschaft Kompost e.V. (www.gz-kompost.de). Plants #1 and #3 produce in addition a liquid fertilizer, which is separated from the solid digestate at the end of stage a) by press filtration and which is also intended for direct use on agricultural soil (replacement of liquid manure). In case of plants #1, #3, and #4 up to 25 wt% of shrub/tree cuttings were added to the solid digestate for composting. All plants used sieving (typically with a 12 or a 20 mm mesh) at the end of the process to assure the necessary purity of their finished composts. Whenever technically possible, we as well took samples of the pre-compost immediately before this final sieving step to evaluate its contribution to the removal of residual BPD fragments. For analysis, composts were passed consecutively through two sieves with mesh sizes of 5 mm and 1 mm, yielding two fragment preparations for IR-analysis namely a > 5 mm fraction corresponding to the contamination by residual “macroplastic” (5 mm is a commonly used upper size limit for “microplastic”, anything larger is macroplastic) and a 1–5 mm fraction corresponding to the regulatory relevant residual contamination by microplastic. The lower limit of 1 mm rather than 2 mm was chosen in anticipation of the expected changes in regulation, where the replacement of the 2 mm limit by a 1 mm limit is imminent.Table 1 Technical data of the investigated plants and incidence of BDP fragments in the sampled composts.Full size tableOccurrence of plastic fragments  > 1 mm in the sampled compostsComposting times of 5–9 weeks were used in the investigated plants (Table 1), which is shorter than the 12 weeks indicated in EN 13432 for the 90% disintegration of a compostable plastic material, but a realistic time span for state-of-the-art technical waste treatment. Since we were not in a position to estimate the quantity of BDP entering the plants, since for technical reasons we were unable to obtain a representative sample, we cannot say, whether any residual BDP detected by us in the finished composts was due to a yet incomplete disintegration process or whether it corresponds to the 10% material still permissible by EN 13432 even after the full composting step. However, in 7 out of the 12 sampled composts and pre-composts fragments with chemical signatures corresponding to the BDPs poly (lactic acid) (PLA) and poly (butylene-adipate-co-terephthalate) (PBAT) were identified in the > 5 mm and/or the 1–5 mm sieving fractions using FTIR analysis3 (Fig. 1; Table 1). All recovered fragments appeared to stem from foils, bags or packaging, since they were thin compared to their length and width (see Suppl Figure S1 for typical examples). Fragments with overlapping signatures, most likely PBAT/PLA mixtures or blends, were also found (see Suppl Figure S2 for the interpretation of the spectra). In addition, the recorded BDP fragment spectra (Fig. 1A) showed high similarity to the FTIR spectra of commercial compostable bags sold in the vicinity of the biowaste treatment plants (Fig. 1B), which together with the geometry of the recovered fragments led us to assuming that the majority of the BDP entered the biowaste in the form of such bags.Figure 1FTIR spectra of BDP fragments from composts and commercial bags. (A) BDP fragments recovered from the composts and (B) the commercial compostable bags. Fragments were coded as follows: p or f for pre-compost or finished compost, followed by the plant number (#1 to #4), an indication of the size fraction ( > 5 mm or 1–5 mm) in which the fragment was found, and finally, the fragment number. Fragment F#1_5mm_4 therefore represents the 4th fragment collected in the  > 5 mm size fraction from the finished compost of plant number 1. Bags were arbitrarily numbered 1–10, see Suppl Table S1 for supplier information. The spectra (in grey) of the reference materials for PLA and PBAT are given as basis for the interpretation. Spectra in red refer to test samples consisting only of PBAT, while those in blue indicate samples composed of PBAT/PLA mixtures.Full size imageThe BDP fragments were found alongside fragments of commodity plastics (mostly PE) in all cases. Finished composts tended to contain fewer and smaller fragments than the corresponding pre-composts. The final sieving of the pre-composts to prepare the finished composts hence appears to be quite effective in removing such fragments, in particular those from the > 5 mm size fraction (Table 1) and for that reason has become state-of-the-art in preparing quality composts (contamination by plastic fragments > 2 mm of less than 0.1 wt%). Given that the size of the fragments is a crucial factor regarding ecological risk, we analyzed the sizes (length Î width) of the BDP fragments in comparison to that of the plastic fragments with signatures of commodity plastics such as PE (Fig. 2). BDP fragments found in a given compost sample tended to be smaller than the fragments stemming from non-BDP materials, which may indicate that BDPs degrade faster or tend to disintegrate into tinier particles than commodity plastics. This may also explain why in the compost from plant #2, no BDP fragments were found in the particle fraction retained by the 5 mm sieve ( > 5 mm fraction), while 19 such particles were found in the fraction then retained by the 1 mm sieve (1–5 mm fraction). Interestingly, plant #2 is the only one included in our study that uses no mechanical breakdown of the incoming biowaste. This reduces the mechanical stress on the incoming material. Mechanical stress can alter the properties of plastic foils such as the crystallinity whereby crystallinity has been shown to influence the biological degradation of BDP such as PLA7.Figure 2Size distribution of plastic fragments  > 1 mm. (A) Fragments found in the finished compost from plant #1, (B) in the finished compost from plant #2, and (C) in the pre-compost from plant #3. For reasons of statistical relevance, only samples containing more than 20 BDP fragments per kg of compost were included in the analysis.Full size imageMaterial characteristics of BDP fragments in comparison to those of commercial biodegradable bagsIn order to verify whether the BDP fragments recovered from the composts differed from the compostable bags in any parameter with possible relevance for biodegradation and environmental impact16, the physico-chemical properties of bags and fragments were studied in detail. Since we wanted to have a maximum of information of the BDP fragments, size/weight was a limiting factor in selecting fragments for analysis. Fragments of at least 1 mg were required for the FT-IR analysis. 5 mg-fragments could be analyzed in addition by 1H-NMR, while the full set of analytics (FT-IR, 1H-NMR, and DSC) required at least 10 mg of sample.For insight into the chemical composition, 1H-NMR spectra of the commercial bags and all suitable BDP fragments were compared (Fig. 3). In case of material mixtures and blends, the 1H-NMR analysis allows quantification of the PBAT/PLA weight ratio in the materials and also of the ratio of the butylene terephthalate (BT) and butylene adipate (BA) units in the involved PBAT polyesters.Figure 31H NMR spectra of BDP fragments from composts and commercial bags. (A) BDP fragments recovered from the composts and (B) the commercial compostable bags. Fragments were coded as follows: p or f for pre-compost or finished compost, followed by the plant number (#1 to #4), an indication of the size fraction ( > 5 mm or 1–5 mm) in which the fragment was found, and finally, the fragment number. Bags were arbitrarily numbered 1–10, see Suppl Table S1 for supplier information. The spectra (in grey) of the reference materials for PLA and PBAT are given as basis for the interpretation. Spectra in red refer to test samples consisting only of PBAT, while those in blue indicate samples composed of PBAT/PLA mixtures. (C) Chemical structures of PLA and PBAT, chemical shifts of the protons are assigned as indicated in the reference spectra in (B).Full size imageThe 1H-NMR spectra corroborate the FTIR measurements in that all investigated commercial bags were made from PBAT/PLA mixtures of varied composition (Table 2). By comparison, some of the fragments, for instance, f#1_5mm_4, appeared to consist of only PBAT. Other fragments, e.g., f#1_1mm_9, were mixtures of PLA and PBAT (Table 2). However, even in the case of PBAT/PLA mixtures, the average PBAT content tended to be higher in the fragments than in the bags, while the BT/BA monomer ratio in the respective PBATs, was also significantly higher in the fragments than in the bags. If we assume the fragments to stem from similar compostable bags as the ones included in our comparison, this would mean that during composting of such a bag, the PLA degrades more quickly than the PBAT, whereas within a given PBAT polyester, the BA unit is more easily degraded than the BT unit. Evidence can indeed be found in the pertinent literature that PLA has faster biodegradation kinetics than PBAT, while BT is more resistant to mineralization than BA17,18.Table 2 Composition of commercial compostable bags and BDP fragments recovered from the composts as analyzed by 1H-NMR.Full size tableNext, differential scanning calorimetry (DSC) was used to analyze fragments compared to commercial bags in regard to the presence of amorphous vs. crystalline domains, a parameter expected to affect biodegradation kinetics and therefore the putative environmental impact of the produced microplastic16 upon release into the environment with the composts. Whereas amorphous domains show glass transition, crystalline domains show melting, both of which can be discerned by the respective phase transition enthalpy in the DSC curves (Fig. 4).Figure 4DSC curves of BDP fragments and compostable bags #1 and #7. Curves for the reference materials (in grey) for PLA and PBAT are given for comparison. Curves were recorded during the first heating run (temperature range: − 50 °C to 200 °C, heating rate: 10 °C min−1). (A) and (B) curves in red refer to test samples consisting only of PBAT, while those in blue indicate samples composed of PBAT/PLA mixtures. Fragments were coded as follows: p or f for pre-compost or finished compost, followed by the plant number (#1 to #4), an indication of the size fraction ( > 5 mm or 1–5 mm) in which the fragment was found, and finally, the fragment number.Full size imageThe curve for the reference PBAT shows a glass transition temperature (Tg) of − 29 °C and a broad melting range between 100 and 140 °C for the crystalline domains, while that of the PLA reference shows a glass transition temperature of 58 °C and a narrower melting peak between 144 °C and 162 °C. The curve for commercial bag #1, which had a comparatively high PLA content, shows a pronounced melting peak in the expected range; the same is the case for fragment p#3_5mm_1 and to a lesser extent for fragment p#3_5mm_9, two fragments, which also have high PLA contents. The DSC curves of the other fragments and bag #1 are undefined in comparison, which is due to their high PBAT content. According to the DSC curves, most of the investigated materials are semicrystalline, i.e., contain both amorphous (glass transition) and crystalline (melting) domains. However, the DCS data alone allow only a qualitative discussion of the differences between fragments and bags.To obtain quantitative data on the crystallinity differences, wide angle X-ray scattering (WAXS) spectra were recorded. WAXS requires fragments at least 3 cm long, which restricted the number of fragment samples to three, all of which were found in pre-compost samples. The corresponding curves are shown in Fig. 5A–C. The spectra of the commercial biodegradable bags are shown in Suppl Figure S3. Foils were in addition prepared by heat pressing from the reference materials for PLA and PBAT in order to include them into the WAXS measurements (Fig. 5D). While the foils produced from the PBAT reference material produced crystallinity peaks at 16.2°, 17.3°, 20.4°, 23.2°, and 24.8°, the foil prepared from the PLA reference material showed only an amorphous halo at 15.5° and 31.5°, which is in accordance with values published in the literature19. A more pronounced crystallinity peak was obtained in the case of an additionally annealed PLA foil.Figure 5WAXS curves with Lorenz fitting for (A) fragment p#3_5mm_1, (B) fragment p#3_5mm_9, and (C) fragment p#4_5mm_2. (D) WAXS curves for foils produced from the PBAT and PLA reference materials; the percent values indicate the crystallinity. The dash lines are the fitting peak curves for the XRD spectrum. Crystallinity can be obtained by dividing the integration area of the fitted peaks by the integration area of the entire spectrum. Fragments were coded as follows: p or f for pre-compost or finished compost, followed by the plant number (#1 to #4), an indication of the size fraction ( > 5 mm or 1–5 mm) in which the fragment was found, and finally, the fragment number.Full size imageIn case of the fragments and bags, the peaks of PLA and PBAT overlapped to some extent in the WAXS spectra, but by conducting Lorenz fitting using Origin software, the overall crystallinity could be calculated as follows:$$chi = { 1}00% , *{text{ Aa}}/left( {{text{Aa }} + {text{ Ac}}} right)$$where χ is the crystallinity and Aa and Ac represent the areas of the amorphous and crystalline peaks.Using this equation, crystallinities of 55% (fragments p#3_5mm_1), 34% (p#3_5mm_9), and 34% (p#4_5mm_2) were calculated for the fragments. The foils prepared in house for the reference materials had similar crystallinities (43% in case of the annealed PLA foil and 26% of the PBAT foil), while the simple PLA foil was amorphous. By comparison, for eight of the commercial bags, crystallinities in the range from 1% to 7% were calculated, whereas these values were 14% and 15% for the remaining two bag types (Suppl Figure S3).The high crystallinity of the larger fragments recovered from the pre-compost samples suggests that crystalline domains of BDP materials may indeed disintegrate more slowly than the amorphous ones, as prior studies on microbial biodegradation have suggested7,8. Admittedly, such large fragments per se would not enter the environment, since the final sieving step used to prepare the finished composts is quite efficient at removing them. However, it is tempting to extrapolate that residual BDP in general are remnants of the more crystal domains of the original material, even though experimental proof of this assumption is at present not possible. 10 wt% of a BDP bag is allowed to remain after standard composting. It is usually assumed that any such residues continue to degrade with comparable speed. However, should these residues correspond to the more crystalline domains, rather than degrading with similar speed as the bulk material, the more crystalline fragments can be expected to persist for a much longer and at present unpredictable length of time in the environment, e.g. when applied to the soil with the composts; in particular, when they are also enriched in PBAT and BT units as suggested by our analysis of the chemical composition. Data from the use of biodegradable foils in agriculture show that the degradation in the environment may take years20. Altogether this may have unforeseen economic and environmental consequences, especially when considering the high fraction of BDP fragments < 5 mm. Putative consequences include changes in soil properties, the soil microbiome and therefore in plant performance21, a factor indispensable for worldwide nutrition.Residues of BDP fragments  1 mm were found in the collected LF samples. This is hardly surprising, given that the LF is produced by press filtration of the digestate after the anaerobic stage. Such a filtration step can be expected to retain fragments > 1 mm in the produced filter cake, which goes into the composting step, leaving the filtrate, i.e. the LF, essentially free of such particles. Anaerobic digestion is currently not assumed to contribute significantly to the degradation of BDP17,22, but the process conditions (mixing, pumping) may promote breakdown of larger fragments, particularly when additives such as plasticizers23 leach out of the material.Since the residual solids content of the LF is low (plant #1: 8.6 wt%, plant #3: 5.8 wt%), a combination of enzymatic-oxidative treatment and µFTIR imaging originally developed for environmental samples from aqueous systems24,25 could be adapted for the analysis (size and chemical signature) of particles in the LF down to a size of 10 µm. The corresponding data are compiled in Table 3. In all cases, residual fragments from PBAT-based polymers represented the dominant plastic fraction in the investigated samples; i.e. approximately 53% of all plastic particles in the LF from plant #1 (11,520 BDP particles per liter) and 65% in the case of plant #3 (12,480 BDP particles per liter). Liquid manure is applied several times a year to fields at a concentration of 2–3 L m−2. According to our analysis > 20,000 BDP microparticles of a size ranging from 10 µm to 500 µm enter each m2 of agricultural soil whenever LF is applied on agricultural surfaces.Table 3 Microplastic fragments (BDP/all) found per liter of liquid fertilizer.Full size tableDue to the complexity of the matrix, a similar analysis of individual plastic fragments  1 mm. Six compost samples representing the more contaminated ones based on the content of fragments > 1 mm, namely, f#1, f#2, p#3, f#3, p#4 and f#4 (nomenclature: f or p for finished or pre-compost, followed by plant number), were extracted with a 90/10 vol% chloroform/methanol mixture. The amounts of PBAT and PLA in the obtained extracts were then quantified via 1H-NMR (Table 4). Briefly, the intensity of characteristic signals in the extract spectra of the compost samples (see Suppl Figure S4) were compared to peak intensities produced by calibration standards of the pure polymer dissolved at a known concentration in the chloroform/methanol. All samples and standards were normalized using the 1,2-dichloroethan signal at 3.73 ppm as internal standard. See also Suppl Figure S5 for an exemplification of the quantification of the PBAT/PLA ratios. Based on the amounts of PBAT and PLA extracted from a known amount of compost, the total mass concentration (wt% dry weight) of these polymers in the composts was calculated.Table 4 Evidence of PBAT and PLA residues caused by fragments  2 mm. Moreover, residues of PBAT and PLA were found in all investigated compost samples, including the finished compost from plant #4, which had shown no contamination by larger BPD fragments (Table 1). The pre-compost from that plant had shown a few contaminating BDP fragments in the > 5 mm fraction. However, in regard to the fragments More