Philippa Kaur

Hou, X., et al. The Cambrian fossils of Chengjiang, China: the flowering of early animal life. 316p., (Wiley Blackwell, Second Edition, 2017).Zhao, F., Zhu, M. & Hu, S. Community structure and composition of the Cambrian Chengjiang biota. Sci. China Earth Sci. 53, 1784–1799 (2010).ADS 

Google Scholar 
Yang, X. et al. A juvenile-rich palaeocommunity of the lower Cambrian Chengjiang biota sheds light on palaeo-boom or palaeo-bust environments. Nat. Ecol. Evol. 5, 1082–1090 (2021).PubMed 

Google Scholar 
Ma, X., Hou, X., Edgecombe, G. D. & Strausfeld, N. J. Complex brain and optic lobes in an early Cambrian arthropod. Nature 490, 258–261 (2012).CAS 
PubMed 
ADS 

Google Scholar 
Saleh, F. et al. Taphonomic bias in exceptionally preserved biotas. Earth Planet. Sci. Lett. 529, 115873 (2020).CAS 

Google Scholar 
Saleh, F. et al. A novel tool to untangle the ecology and fossil preservation knot in exceptionally preserved biotas. Earth Planet. Sci. Lett. 569, 117061 (2021).CAS 

Google Scholar 
Harper, D. A. et al. The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian explosion. J. Geol. Soc. 176, 1023–1037 (2019).ADS 

Google Scholar 
Nanglu, K., Caron, J. B. & Gaines, R. R. The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia. Paleobiology 46, 58–81 (2020).
Google Scholar 
Tanaka, G., Hou, X., Ma, X., Edgecombe, G. D. & Strausfeld, N. J. Chelicerate neural ground pattern in a Cambrian great appendage arthropod. Nature 502, 364–367 (2013).CAS 
PubMed 
ADS 

Google Scholar 
Cong, P., Ma, X., Hou, X., Edgecombe, G. D. & Strausfeld, N. J. Brain structure resolves the segmental affinity of anomalocaridid appendages. Nature 513, 538–542 (2014).CAS 
PubMed 
ADS 

Google Scholar 
Liu, Y., Ortega-Hernández, J., Zhai, D. & Hou, X. A reduced labrum in a Cambrian great-appendage euarthropod. Curr. Biol. 30, 3057–3061 (2020).CAS 
PubMed 

Google Scholar 
Liu, Y. et al. Computed tomography sheds new light on the affinities of the enigmatic euarthropod Jianshania furcatus from the early Cambrian Chengjiang biota. BMC Evol. Biol. 20, 1–17 (2020).
Google Scholar 
Gabbott, S. E., Hou, X.-G., Norry, M. J. & Siveter, D. J. Preservation of Early Cambrian animals of the Chengjiang biota. Geology 32, 901–904 (2004).CAS 
ADS 

Google Scholar 
Gaines, R. R. et al. Mechanism for Burgess Shale-type preservation. Proc. Natl. Acad. Sci. 109, 5180–5184 (2012).CAS 
PubMed 
PubMed Central 
ADS 

Google Scholar 
Forchielli, A., Steiner, M., Kasbohm, J., Hu, S. & Keupp, H. Taphonomic traits of clay-hosted early Cambrian Burgess Shale-type fossil Lagerstätten in South China. Palaeogeogr, Palaeoclimatol. Palaeoecol. 398, 59–85 (2014).
Google Scholar 
Ma, X., Edgecombe, G. D., Hou, X., Goral, T. & Strausfeld, N. J. Preservational pathways of corresponding brains of a Cambrian euarthropod. Curr. Biol. 25, 2969–2975 (2015).CAS 
PubMed 

Google Scholar 
Hammarlund, E. U. et al. Early Cambrian oxygen minimum zone-like conditions at Chengjiang. Earth Planet. Sci. Lett. 475, 160–168 (2017).CAS 
ADS 

Google Scholar 
Qi, C. et al. Influence of redox conditions on animal distribution and soft-bodied fossil preservation of the Lower Cambrian Chengjiang Biota. Palaeogeogr. Palaeoclimatol. Palaeoecol. 507, 180–187 (2018).
Google Scholar 
Saleh, F., Daley, A. C., Lefebvre, B., Pittet, B. & Perrillat, J. P. Biogenic iron preserves structures during fossilization: a hypothesis: iron from decaying tissues may stabilize their morphology in the fossil record. BioEssays 42, 1900243 (2020).CAS 

Google Scholar 
Daley, A. C. et al. Insights into soft-part preservation from the Early Ordovician Fezouata Biota. Earth Sci. Rev. 213, 103464 (2021).
Google Scholar 
Pu, X. C., et al. Cambrian lithofacies, paleogeography and mineralization in south China, Geological Publishing House, Beijing, 191 p. (1992).Zhu, M. Y., Zhang, J. M. & Li, G. X. Sedimentary environments of the early Cambrian Chengjiang biota: sedimentology of the Yu’anshan Formation in Chengjiang County, eastern Yunnan. Acta Palaeontol. Sin. 40, 80–105 (2001).
Google Scholar 
Babcock, L. E. & Zhang, W. Stratigraphy, palaeontology, and depositional setting of the Chengjiang Lagerstätte (Lower Cambrian), Yunnan, China. Palaeoworld 13, 66–86 (2001).
Google Scholar 
Babcock, L. E., Zhang, W. & Leslie, S. A. The Chengjiang biota: record of the Early Cambrian diversification of life and clues to exceptional preservation of fossils. GSA Today 11, 4–9 (2001).
Google Scholar 
MacKenzie, L. A., Hofmann, M. H., Junyuan, C. & Hinman, N. W. Stratigraphic controls of soft-bodied fossil occurrences in the Cambrian Chengjiang Biota Lagerstätte, Maotianshan Shale, Yunnan Province, China. Palaeogeogr. Palaeoclimatol. Palaeoecol. 420, 96–115 (2015).
Google Scholar 
Chen, J. Y. & Lindström, M. A lower Cambrian soft-bodied fauna from Chengjiang, Yunnan, China. Geologiska Föreningen i Stockholm Förhandlingar 113, 79–81 (1991).
Google Scholar 
Jin, Y. G., Wang, H. Y. & Wang, W. Palaeoecological aspect of branchiopods from Chiungchussu Formation of Early Cambrian Age, Eastern Yunnan, China. Palaeoecol. China 1, 25–47 (1991).CAS 

Google Scholar 
Hu, S. Taphonomy and palaeoecology of the Early Cambrian Chengjiang Biota from eastern Yunnan, China. Berl. Paläobiologische Abhandlungen 7, 189 (2005).ADS 

Google Scholar 
Schieber, J., Southard, J. & Thaisen, K. Accretion of mudstone beds from migrating floccule ripples. Science 318, 1760–1763 (2007).CAS 
PubMed 
ADS 

Google Scholar 
Lamb, M. P., Myrow, P. M., Lukens, C., Houck, K. & Strauss, J. Deposits from wave-influenced turbidity currents: Pennsylvanian Minturn Formation, Colorado, USA. J. Sediment. Res. 78, 480–498 (2008).ADS 

Google Scholar 
Baas, J. H., Best, J. L., Peakall, J. & Wang, M. A phase diagram for turbulent, transitional, and laminar clay suspension flows. J. Sediment. Res. 79, 162–183 (2009).ADS 

Google Scholar 
Plint, A. G. & Macquaker, J. H. Bedload Transport of Mud Across a Wide, Storm-Influenced Ramp: Cenomanian–Turonian Kaskapau Formation, Western Canada Foreland Basin—Reply. J. Sediment. Res. 83, 1200–1201 (2013).
Google Scholar 
Bohacs, K. M., Lazar, O. R. & Demko, T. M. Parasequence types in shelfal mudstone strata—Quantitative observations of lithofacies and stacking patterns, and conceptual link to modern depositional regimes. Geology 42, 131–134 (2014).ADS 

Google Scholar 
Lazar, O. R., Bohacs, K. M., Macquaker, J. H., Schieber, J. & Demko, T. M. Capturing key attributes of fine-grained sedimentary rocks in outcrops, cores, and thin sections: nomenclature and description guidelines. J. Sediment. Res. 85, 230–246 (2015).CAS 
ADS 

Google Scholar 
Wheatcroft, R. A. Oceanic flood sedimentation: a new perspective. Continent. Shelf Res. 20, 2059–2066 (2000).ADS 

Google Scholar 
Wright, L. D. & Friedrichs, C. T. Gravity-driven sediment transport on continental shelves: a status report. Continent. Shelf Res. 26, 2092–2107 (2006).ADS 

Google Scholar 
Bhattacharya, J. P. & MacEachern, J. A. Hyperpycnal rivers and prodeltaic shelves in the Cretaceous seaway of North America. J. Sediment. Res. 79, 184–209 (2009).ADS 

Google Scholar 
Ichaso, A. A. & Dalrymple, R. W. Tide-and wave-generated fluid mud deposits in the Tilje Formation (Jurassic), offshore Norway. Geology 37, 539–542 (2009).ADS 

Google Scholar 
Schieber, J. Experimental testing of the transport-durability of shale lithics and its implications for interpreting the rock record. Sediment. Geol. 331, 162–169 (2016).ADS 

Google Scholar 
Zavala, C. & Arcuri, M. Intrabasinal and extrabasinal turbidites: Origin and distinctive characteristics. Sediment. Geol. 337, 36–54 (2016).ADS 

Google Scholar 
Boulesteix, K., Poyatos-Moré, M., Hodgson, D. M., Flint, S. S. & Taylor, K. G. Fringe or background: characterizing deep-water mudstones beyond the basin-floor fan sandstone pinchout. J. Sediment. Res. 90, 1678–1705 (2020).ADS 

Google Scholar 
Dumas, S. & Arnott, R. W. C. Origin of hummocky and swaley cross-stratification—the controlling influence of unidirectional current strength and aggradation rate. Geology 34, 1073–1076 (2006).ADS 

Google Scholar 
Perillo, M. M. et al. A unified model for bedform development and equilibrium under unidirectional, oscillatory and combined‐flows. Sedimentology 61, 2063–2085 (2014).
Google Scholar 
Jelby, M. E., Grundvåg, S. A., Helland‐Hansen, W., Olaussen, S. & Stemmerik, L. Tempestite facies variability and storm‐depositional processes across a wide ramp: Towards a polygenetic model for hummocky cross‐stratification. Sedimentology 67, 742–781 (2020).
Google Scholar 
Collins, D. S., Johnson, H. D., Allison, P. A., Guilpain, P. & Damit, A. R. Coupled ‘storm‐flood’depositional model: application to the Miocene–Modern Baram Delta Province, north‐west Borneo. Sedimentology 64, 1203–1235 (2017).
Google Scholar 
Dillinger, A., Vaucher, R. & Haig, D. W. Refining the depositional model of the lower Permian Carynginia Formation in the northern Perth Basin: anatomy of an ancient mouth bar. Aust. J. Earth Sci. 69, 135–151 (2022).CAS 
ADS 

Google Scholar 
Zavala, C. Hyperpycnal (over density) flows and deposits. J. Palaeogeogr. 9, 1–21 (2020).
Google Scholar 
Lin, W. & Bhattacharya, J. P. Storm‐flood‐dominated delta: a new type of delta in stormy oceans. Sedimentology 68, 1109–1136 (2021).
Google Scholar 
MacEachern, J. A., Raychaudhuri, I. & Pemberton, S. G. Stratigraphic applications of the Glossifungites ichnofacies: delineating discontinuities in the rock record. In Applications of Ichnology to Petroleum Exploration: a Core Workshop, ed. S.G. Pemberton. Soc. Sediment. Geol. Core Workshop 17, 169–198 (1992).
Google Scholar 
Hubbard, S. M. & Shultz, M. R. Deep burrows in submarine fan-channel deposits of the Cerro Toro Formation (Cretaceous), Chilean Patagonia: implications for firmground development and colonization in the deep sea. Palaios 23, 223–232 (2008).ADS 

Google Scholar 
Buatois, L. A. & Mángano, M. G. Ichnology: organism-substrate interactions in space and time. Cambridge University Press (2011).Droser, M. L., Jensen, S. & Gehling, J. G. Trace fossils and substrates of the terminal Proterozoic–Cambrian transition: implications for the record of early bilaterians and sediment mixing. Proc. Natl Acad. Sci. 99, 12572–12576 (2002).CAS 
PubMed 
PubMed Central 
ADS 

Google Scholar 
Droser, M. L., Jensen, S. & Gehlîng, J. G. Development of early Palaeozoic ichnofabrics: evidence from shallow marine siliciclastics. Geological Society, London, Special Publications 228, 383–396 (2004).Macquaker, J. H., Bentley, S. J. & Bohacs, K. M. Wave-enhanced sediment-gravity flows and mud dispersal across continental shelves: Reappraising sediment transport processes operating in ancient mudstone successions. Geology 38, 947–950 (2010).ADS 

Google Scholar 
Myrow, P. M., Fischer, W. & Goodge, J. W. Wave-modified turbidites: combined-flow shoreline and shelf deposits, Cambrian, Antarctica. J. Sediment. Res. 72, 641–656 (2002).CAS 
ADS 

Google Scholar 
Mackay, D. A. & Dalrymple, R. W. Dynamic mud deposition in a tidal environment: the record of fluid-mud deposition in the Cretaceous Bluesky Formation, Alberta, Canada. J. Sediment. Res. 81, 901–920 (2011).ADS 

Google Scholar 
Birgenheier, L. P., Horton, B., McCauley, A. D., Johnson, C. L. & Kennedy, A. A depositional model for offshore deposits of the lower Blue Gate Member, Mancos Shale, Uinta Basin, Utah, USA. Sedimentology 64, 1402–1438 (2017).
Google Scholar 
Lobza, V. & Schieber, J. Biogenic sedimentary structures produced by worms in soupy, soft muds; observations from the Chattanooga Shale (Upper Devonian) and experiments. J. Sediment. Res. 69, 1041–1049 (1999).ADS 

Google Scholar 
Savrda, C. E. & Bottjer, D. J. Trace-fossil model for reconstruction of paleo-oxygenation in bottom waters. Geology 14, 3–6 (1986).CAS 
ADS 

Google Scholar 
Dashtgard, S. E., Snedden, J. W. & MacEachern, J. A. Unbioturbated sediments on a muddy shelf: hypoxia or simply reduced oxygen saturation? Palaeogeogr. Palaeoclimatol. Palaeoecol. 425, 128–138 (2015).
Google Scholar 
Dashtgard, S. E. & MacEachern, J. A. Unburrowed mudstones may record only slightly lowered oxygen conditions in warm, shallow basins. Geology 44, 371–374 (2016).ADS 

Google Scholar 
Pattison, S. A., Bruce Ainsworth, R. & Hoffman, T. A. Evidence of across‐shelf transport of fine‐grained sediments: turbidite‐filled shelf channels in the Campanian Aberdeen Member, Book Cliffs, Utah, USA. Sedimentology 54, 1033–1064 (2007).ADS 

Google Scholar 
Buatois, L. A. et al. Sedimentological and ichnological signatures of changes in wave, river and tidal influence along a Neogene tropical deltaic shoreline. Sedimentology 59, 1568–1612 (2012).CAS 
ADS 

Google Scholar 
Vaucher, R. et al. Tectonic controls on late Cambrian-Early Ordovician deposition in Cordillera Oriental (Northwest Argentina). Int. J. Earth Sci. 109, 1897–1920 (2020).CAS 

Google Scholar 
Paz, M. et al. Bottomset and foreset sedimentary processes in the mixed carbonate-siliciclastic Upper Jurassic-Lower Cretaceous Vaca Muerta Formation, Picún Leufú Area, Argentina. Sediment. Geol. 389, 161–185 (2019).CAS 
ADS 

Google Scholar 
Zavala, C. et al. Deltas: a new classification expanding Bates’s concepts. J. Palaeogeogr. 10, 1–15 (2021).
Google Scholar 
Davies, N. S. & Gibling, M. R. Cambrian to Devonian evolution of alluvial systems: the sedimentological impact of the earliest land plants. Earth-Sci. Rev. 98, 171–200 (2010).ADS 

Google Scholar 
McMahon, W. J. & Davies, N. S. Evolution of alluvial mudrock forced by early land plants. Science 359, 1022–1024 (2018).CAS 
PubMed 
ADS 

Google Scholar 
MacEachern, J. A., Bann, K. L., Bhattacharya, J. P. & Howell Jr, C. D. Ichnology of deltas: organism responses to the dynamic interplay of rivers, waves, storms, and tides. In River Deltas — Concepts, Models, and Examples: SEPM (eds Bhattacharya, J. P. & Giosan, L.), 49–85 (Special Publication, 2005).Buatois, L. A. & Mángano, M. G. Recurrent patterns and processes: the significance of ichnology in evolutionary paleoecology. In The trace-fossil record of major evolutionary events (eds Mángano, M. G. & Buatois, L. A.), Vol. 2, 449–473, Mesozoic and Cenozoic (Topics in Geobiology 40, 2016).Buatois, L. A. & Mángano, M. G. The other biodiversity record: Innovations in animal-substrate interactions through geologic time. GSA Today 28, 4–10 (2018).
Google Scholar 
Thayer, C. W. Biological bulldozers and the evolution of marine benthic communities. Science 203, 458–461 (1979).CAS 
PubMed 
ADS 

Google Scholar 
Thayer C. W. Sediment-mediated biological disturbance and the evolution of the marine benthos. In: Tevesz M. J. S., McCall P. L. (eds) Biotic interactions in recent and fossil benthic communities. Plenum, Zeitschr (1983).Buatois, L. A., et al. The Mesozoic marine revolution. In The trace-fossil record of major evolutionary events, (eds Mángano, M. G. & Buatois, L. A.), Vol. 40, 19–134. Mesozoic and Cenozoic (Topics in Geobiology, 2016).Gougeon, R. C., Mángano, M. G., Buatois, L. A., Narbonne, G. M. & Laing, B. A. Early Cambrian origin of the shelf sediment mixed layer. Nat. Commun. 9, 1909 (2018).PubMed 
PubMed Central 
ADS 

Google Scholar 
Herbers, D. S., MacNaughton, R. B., Timmer, E. R., Gingras, M. K. & Hubbard, S. Sedimentology and ichnology of an Early-Middle Cambrian storm-influenced barred shoreface succession, Colville Hills, Northwest territories. Bull. Can. Petrol. Geol. 64, 538–554 (2016).
Google Scholar 
Jensen, S. Trace fossils from the Lower Cambrian Mickwitzia sandstone, south-central Sweden. Foss. Strat. 42, 1–111 (1997).
Google Scholar 
Mángano, M. G. & Buatois, L. A. Decoupling of body-plan diversification and ecological structuring during the Ediacaran-Cambrian transition: Evolutionary and geobiological feedbacks. Proc. R. Soc. B. 281, 1–9 (2014).
Google Scholar 
Gaines, R. R. Burgess Shale-type preservation and its distribution in space and time. In Reading and Writing of the Fossil Record: Preservational Pathways to Exceptional Fossilization, (eds Laflamme, M., Schiffbauer, J. D. & Darroch, S. A. F.) Vol. 20, 123–146 (Paleontol. Soc. Pap. 2014).Enright, O. G. B., Minter, N. J., Sumner, E. J., Mángano, M. G. & Buatois, L. A. Flume experiments reveal flows in the Burgess Shale can sample and transport organisms across substantial distances. Commun. Earth Environ. 2, 1–7 (2021).
Google Scholar 
Daily, B., Moore, P. S. & Rust, B. R. Terrestrial‐marine transition in the Cambrian rocks of Kangaroo Island, South Australia. Sedimentology 27, 379–399 (1980).ADS 

Google Scholar 
Buatois, L. A., Mángano, M. G. & Pattison, S. A. Ichnology of prodeltaic hyperpycnite–turbidite channel complexes and lobes from the Upper Cretaceous Prairie Canyon Member of the Mancos Shale, Book Cliffs, Utah, USA. Sedimentology 66, 1825–1860 (2019).
Google Scholar 
Serra, F., Balseiro, D., Vaucher, R. & Waisfeld, B. G. Structure of Trilobite communities along a delta-marine gradient (lower Ordovician; Northwestern Argentina). Palaios 36, 39–52 (2021).ADS 

Google Scholar 
Saleh, F. et al. Storm-induced community dynamics in the Fezouata Biota (Lower Ordovician, Morocco). Palaios 33, 535–541 (2018).ADS 

Google Scholar 
Saleh, F. et al. Large trilobites in a stress-free Early Ordovician environment. Geol. Mag. 158, 261–270 (2021).ADS 

Google Scholar 
Tabb, D. C. & Jones, A. C. Effect of Hurricane Donna on the aquatic fauna of North Florida Bay. Trans. Am. Fish. Soc. 91, 375–378 (1962).
Google Scholar 
Barry, J. P. & Dayton, P. K. Physical heterogeneity and the organization of marine communities. In Ecological heterogeneity pp. 270–320. (Springer, New York, NY 1991).Shu, D. G., Zhang, X. L. & Chen, L. Reinterpretation of Yunnanozoon as the earliest known hemichordate. Nature 380, 428–430 (1996).CAS 
ADS 

Google Scholar 
Russell, M. P. Echinoderm responses to variation in salinity. Adv. Mar. Biol. 66, 171–212 (2013).PubMed 

Google Scholar 
Zhao, Y. et al. Kaili Biota: a taphonomic window on diversification of metazoans from the basal Middle Cambrian: Guizhou, China. Acta Geol. Sin. 79, 751–765 (2005).
Google Scholar  More

Site descriptionIn 2012, a field experiment was conducted in the Aksu National Experimental Station of Oasis Farmland Ecosystem27 (40°37′ N, 80°45′ E, altitude 1028 m) (Fig. 1), located in the west of Tarim River Basin in Xinjiang Province, China. The experimental area had a typical temperate arid climate. During the study period (May to October), the average minimum and maximum temperatures varied between 16.7 and 34.8 ℃ respectively.Figure 1Location of the Aksu National Experimental Station of Oasis Farmland Ecosystem (the map was created by software: QGIS Version 3.16.15 LTR: URL, https://www.qgis.org/en/site/).Full size imageThe cotton fields where the experiment conducted were public land, belong to Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, China. With the permissions of Xinjiang Institute of Ecology and Geography, we conducted experiments in the cotton field of the Aksu National Experimental Station of Oasis Farmland Ecosystem.Experimental designTwo treatments, each 10 m × 10 m in size, were established on one of cotton fields at the Aksu National Experimental Station of Oasis Farmland Ecosystem on April 5, 2012.One treatment planting cotton with TC method, the other with MC method. For the MC method, a high-density and air-tight transparent polythene film (0.01–0.02 mm thick, 1.25 m wide) was placed over the soil surface before sowing. Small holes (0.02 m × 0.02 m, at 0.1 m intervals within a row) in the plastic film were made to place cotton seeds. Four rows were sown on each strip of plastic film. For the TC treatment, the plants were sown as that for the MC treatment. The planting density (266 667plant ha−1) and irrigation pattern (frequency and volume of irrigation) for the TC method were entirely consistent with those for the MC method.Half-hourly measurements of soil CO2 efflux, soil temperature and moisture were made on 6 June 2012. The whole experiment was completed on 4 November 2012. According to irrigation, the whole experiment can be divided into three stages: stage before irrigation (from 6 to 24 June), during irrigation (from 25 June to 10 October) and irrigation stop stage (from 11October to 4 November). During the irrigation period, we conducted seven times of irrigation (once in two week). The water-soluble compound fertilizer (N + P2O5 + K2O ≥ 51%) was used for fertilization in the experimental field, and the application rate was 30 g m−2. We dissolved water-soluble compound fertilizer in water and sprayed into the field by sprayer. During the irrigation period, the fertilizer was applied for 5 times.The cottonseeds we used in this study comply with the provisions of the regulations of the People’s Republic of China on Seed Administration and the detailed rules for the implementation of crop seeds. The fertilization we used in this study comply with the provisions of the People’s Republic of China on Chemical fertilizer standard. All the experiments we conducted in the cotton field of Aksu oasis farmland ecosystem National Experimental Station met the provisions of the agricultural law of the People’s Republic of China. We also carried out the experiment of this study under the guidance of the provisions of the measures for the administration of national field scientific observation and research stations.Field measurement of soil CO2 concentrationSolid-state CO2 sensors (GMM221 and GMM222, Vaisala, Finland) were installed in the midpoint of each treatment to measure soil CO2 concentration. A cable connected each soil probe with a transimitter body placed on the ground. The transimitter sent output signals from the probe to a data logger (CR1000, Campbell Scientific Inc., Logan, UT, USA) and to an optional LCC display on the transmitter.In each treatment, four CO2 concentration sensors were buried at depths of 0 cm, 5 cm, 10 cm and 15 cm. Soil CO2 concentrations were recorded once in 30 min. The measurement of soil CO2 concentrations were conducted from 6 June 2012 to 4 November 2012.On 8 November, these sensors were excavated and recalibrated in the laboratory. We found no change in the slope or offset.Environmental and soil CO2 efflux measurementsThe soil water content and temperature at the same soil depth with solid-state CO2 sensors were measured on the cotton fields at the Aksu National Experimental Station of Oasis Farmland Ecosystem27,28, respectively. Soil volumetric water content and soil temperature were measured using soil moisture probes (pF-Meter, EcoTech GmbH, Bonn, Germany)26 and temperature probes (PT100,Heraeus Sensor Technology, Kleinostheim, Germany)26, respectively.Bulk density was determined by core method29. Briefly, a cylindrical metal sampler (volume of 100cm3) was inserted into the soil and carefully removed to preserve the sample. The sample was oven-dried at 105 °C and weighed. The ratio between dry weight of the soil sample and the cylinder volume was applied to provide the bulk density.Half-hourly soil CO2 efflux measurements were conducted using a closed dynamic chamber method26 (CIRAS-1 PP Systems, Hitchin, UK) on the TC treatment, beginning on 6 June 2012. A chamber, with a diameter of 9.96 cm and a volume of 1, 170 cm3 was inserted into the soil at depth of 3 cm. Soil CO2 concentrations were measured by infrared gas analyzer. The collecting of CO2 from each sampling point took 120 s to get reliable estimates of soil CO2 efflux.Data analysisIn order to calculate CO2 efflux in soil, Fick’s first law of diffusion was used:$$F_{i} = – D_{s} frac{dc}{{dz}}$$
(1)
where Fi is the CO2 efflux at depth zi, Ds the CO2 diffusion coefficient in the soil, and dc / dz the vertical soil CO2 gradient. In this study, the vertical CO2 gradient (dC/dz) was approximately a constant at different depths of soil in our site for the field conditions experienced in the TC treatment during study period. However, a quadratic function of depth to concentrations fitted to soil CO2 concentration gradients in the MC treatment.Ds can be estimated as$$D_{s} = xi D_{a}$$
(2)
where ξ is the gas tortuosity factor and Da is the CO2 diffusion coefficient in free air. The effect of temperature and pressure on Da is given by$$D_{a} = D_{a} 0left( {frac{T}{293.15}} right)^{1.75} left( {frac{P}{101.3}} right)$$
(3)
where T is the temperature (K), P the air pressure (kPa), Dao a reference value of Da at 20 °C (293.15 K) and 101.3 kPa, and is given as 14.7 mm2 s–130 .There are several empirical models in the literature for computing ξ31. We used the Millington–Quirk model32:$$xi = frac{{alpha^{10/3} }}{{phi^{2} }}$$
(4)
where a is the volumetric air content (air-filled porosity), Φ is the porosity. Note,$$phi = alpha + theta = 1 – frac{{rho_{b} }}{{rho_{m} }}$$
(5)
where ρb is the bulk density, and ρm is the particle density for the mineral soil.Soil surface CO2 efflux was calculated using the CO2 gradient flux method based on CO2 concentrations within the soil profile1. Briefly, the flux of CO2 between any two layers in the soil profile was calculated using the Moldrup model33.In order to determine soil CO2 storage, the equation for CO2 was performed.$${S}_{C{O}_{2}}=frac{partial (aC)}{partial t}$$
(6)
where C (ppm) is the concentration of CO2 within the soil pores, (a) is the aerial porosity of the soil layer, D is the molecular diffusivity of CO2 with the soil, and S(µmol m−3 s−1)is the source strength in the soil layer at depth.We determined temperature responses for soil CO2 efflux using the van’t Hoff equation34 (Eq. 7);$$R = R0e^{BT}$$
(7)
where R is soil CO2 efflux, T is soil temperature (°C) at 10 cm depth, and R0 is the soil respiration rate at a reference temperature of 0 °C (µmol m−3 s−1).The Q10 value for Eq. (8) was calculated according to definition as:$$Q_{{{1}0}} = R_{{{text{T}} + {1}0}} /R_{{text{T}}} = {text{ e}}^{{{1}0{text{B}}}}$$
(8)
where RT and RT+10 are Rr or Rd rates at temperature T and T + 10, respectively. The Q10 value is independent of temperature in Eq. (8). More

Alves, J. A. et al. Costs, benefits, and fitness consequences of different migratory strategies. Ecology 94(1), 11–17 (2013).PubMed 

Google Scholar 
Alexander, R. M. When is migration worthwhile for animals that walk, swim or fly?. J. Avian Biol. 29(4), 387–394 (1998).
Google Scholar 
Wikelski, M. et al. Costs of migration in free-flying songbirds. Nature 423, 704 (2003).ADS 
CAS 
PubMed 

Google Scholar 
Alerstam, T., Hedenström, A. & Åkesson, S. Long-distance migration: evolution and determinants. Oikos 103(2), 247–260 (2003).
Google Scholar 
Alerstam, T. Optimal bird migration revisited. J. Ornithol. 152, 5–23 (2011).
Google Scholar 
Hedenstrom, A. & Alerstam, T. Optimum fuel loads in migratory birds: Distinguishing between time and energy minimization. J. Theor. Biol. 189, 227–234 (1997).ADS 
CAS 
PubMed 

Google Scholar 
Åkesson, S. & Helm, B. Endogenous programs and flexibility in bird migration. Front. Ecol. Evol. 8, 78 (2020).
Google Scholar 
Jiguet, F. et al. Desert crossing strategies of migrant songbirds vary between and within species. Sci. Rep. 9(1), 20248 (2019).ADS 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Senner, N. R., Morbey, Y. E. & Sandercock, B. K. Editorial: Flexibility in the migration strategies of animals. Front. Ecol. Evol. 8, 111 (2020).
Google Scholar 
Mellone, U., López-López, P., Limiñana, R., Piasevoli, G. & Urios, V. The trans-equatorial loop migration system of Eleonora’s falcon: Differences in migration patterns between age classes, regions and seasons. J. Avian Biol. 44, 417–426 (2013).
Google Scholar 
Chevallier, D. et al. Influence of weather conditions on the flight of migrating black storks. Proc. Biol. Sci. 277(1695), 2755–2764 (2010).CAS 
PubMed 
PubMed Central 

Google Scholar 
Verhelst, B., Jansen, J. & Vansteelant, W. South West Georgia: An important bottleneck for raptor migration during autumn. Ardea 99, 137–146 (2011).
Google Scholar 
Klaassen, R. H. G., Strandberg, R., Hake, M. & Alerstam, T. Flexibility in daily travel routines causes regional variation in bird migration speed. Behav. Ecol. Sociobiol. 62(9), 1427–1432 (2008).
Google Scholar 
Alerstam, T. Detours in bird migration. J. Theor. Biol. 209(3), 319–331 (2001).ADS 
CAS 
PubMed 

Google Scholar 
Alerstam, T. & Hedenström, A. The development of bird migration theory. J. Avian Biol. 29(4), 343–369 (1998).
Google Scholar 
Liechti, F., Klaassen, M. & Bruderer, B. Predicting migratory flight altitudes by physiological migration models. Auk 117, 205–214 (2000).
Google Scholar 
Senner, N. R. et al. High-altitude shorebird migration in the absence of topographical barriers: Avoiding high air temperatures and searching for profitable winds. Proc. Biol. Sci. 2018, 285 (1881).
Google Scholar 
Norevik, G., Akesson, S., Andersson, A., Backman, J. & Hedenstrom, A. Flight altitude dynamics of migrating European nightjars across regions and seasons. J. Exp. Biol. 224(20), jeb242836 (2021).PubMed 
PubMed Central 

Google Scholar 
Hadjikyriakou, T. G., Nwankwo, E. C., Virani, M. Z. & Kirschel, A. N. G. Habitat availability influences migration speed, refueling patterns and seasonal flyways of a fly-and-forage migrant. Mov. Ecol. 8, 10 (2020).PubMed 
PubMed Central 

Google Scholar 
Strandberg, R., Klaassen, R. H. G., Olofsson, P. & Alerstam, T. Daily travel schedules of adult Eurasian Hobbies Falco subbuteo—Variability in flight hours and migration speed along the route. Ardea 97(3), 287–295 (2009).
Google Scholar 
Strandberg, R. & Alerstam, T. The strategy of fly-and-forage migration, illustrated for the osprey (Pandion haliaetus). Behav. Ecol. Sociobiol. 61(12), 1865–1875 (2007).
Google Scholar 
McKinnon, E. A. & Love, O. P. Ten years tracking the migrations of small landbirds: Lessons learned in the golden age of bio-logging. Auk 135(4), 834–856 (2018).
Google Scholar 
Backman, J. et al. Actogram analysis of free-flying migratory birds: New perspectives based on acceleration logging. J. Comp. Physiol. A Neuroethol. Sens. Neural Behav. Physiol. 203(6–7), 543–564 (2017).PubMed 
PubMed Central 

Google Scholar 
Evens, R., Beenaerts, N., Witters, N. & Artois, T. Study on the foraging behaviour of the European nightjar Caprimulgus europaeus reveals the need for a change in conservation strategy in Belgium. J. Avian Biol. 48(9), 1238–1245 (2017).
Google Scholar 
Evens, R. et al. Lunar synchronization of daily activity patterns in a crepuscular avian insectivore. Ecol. Evol. 10(14), 7106–7116 (2020).PubMed 
PubMed Central 

Google Scholar 
Liechti, F. et al. Miniaturized multi-sensor loggers provide new insight into year-round flight behaviour of small trans-Sahara avian migrants. Mov. Ecol. 6, 19 (2018).PubMed 
PubMed Central 

Google Scholar 
Liechti, F., Witvliet, W., Weber, R. & Bachler, E. First evidence of a 200-day non-stop flight in a bird. Nat. Commun. 4, 2554 (2013).ADS 
PubMed 

Google Scholar 
Dhanjal-Adams, K. L. PAMLr: Suite of functions for manipulating pressure, activity, magnetism and light data in R. (2020).Lisovski, S. et al. Light-level geolocator analyses: A user’s guide. J. Anim. Ecol. 89(1), 221–236 (2020).PubMed 

Google Scholar 
Lisovski, S. et al. Geolocation by light: Accuracy and precision affected by environmental factors. Methods Ecol. Evol. 3(3), 603–612 (2012).
Google Scholar 
Wotherspoon, S., Sumner, M., Lisovski, S. SGAT-Package: Solar/Satellite Geolocation for Animal Tracking. (2021). R package version 0.1.3. GitHub Repository.Bauer, R. RchivalTag: Analyzing Archival Tagging Data. R package version 0.1.2. (2020).Sjöberg, S. et al. Barometer logging reveals new dimensions of individual songbird migration. J. Avian Biol. 49(9), e01821 (2018).
Google Scholar 
Evens, R. et al. Migratory pathways, stopover zones and wintering destinations of Western European Nightjars Caprimulgus europaeus. Ibis 159(3), 680–686 (2017).
Google Scholar 
Becker, J. J. et al. Global bathymetry and elevation data at 30 arc seconds resolution: SRTM30_PLUS. Mar. Geodesy 32(4), 355–371 (2009).
Google Scholar 
Ricketts, T. H. Terrestrial Ecoregions of North America: A Conservation Assessment (Island Press, 1999).
Google Scholar 
Olson, D. M. et al. Terrestrial ecoregions of the world: A new map of life on earth. Bioscience 51(11), 933–938 (2001).
Google Scholar 
QGIS-Development-Team: QGIS Geographic Information System. Open Source Geospatial Foundation (2021).Vansteelant, W. M. G., Gangoso, L., Bouten, W., Viana, D. S. & Figuerola, J. Adaptive drift and barrier-avoidance by a fly-forage migrant along a climate-driven flyway. Mov. Ecol. 9(1), 37 (2021).PubMed 
PubMed Central 

Google Scholar 
Brooks, M. E. et al. glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling. R J. 9(2), 378–400 (2017).
Google Scholar 
Hartig, F. DHARMa: Residual Diagnostics for Hierarchical Multi-Level/Mixed) Regression Models. R package version 0.3.3.0. (2020).Lenth, R. emmeans: Estimated Marginal Means, aka Least-Squares Means. R package version 1.5.1. (2020).Akesson, S., Bianco, G. & Hedenstrom, A. Negotiating an ecological barrier: Crossing the Sahara in relation to winds by common swifts. Philos. Trans. R. Soc. Lond. B Biol. Sci. 371(1704), 20150393 (2016).PubMed 
PubMed Central 

Google Scholar 
Strandberg, R., Klaassen, R. H. G., Hake, M., Olofsson, P. & Alerstam, T. Converging migration routes of Eurasian Hobbies Falco subbuteo crossing the African equatorial rain forest. Proc. R. Soc. B 276, 727–733 (2009).PubMed 

Google Scholar 
Rodriguez-Ruiz, J. et al. Disentangling migratory routes and wintering grounds of Iberian near-threatened European Rollers Coracias garrulus. PLoS ONE 9(12), e115615 (2014).ADS 
PubMed 
PubMed Central 

Google Scholar 
Vickery, J. A. et al. The decline of Afro-Palaearctic migrants and an assessment of potential causes. Ibis 156, 1–22 (2014).
Google Scholar 
Evens, R. et al. Proximity of breeding and foraging areas affects foraging effort of a crepuscular, insectivorous bird. Sci. Rep. 8(1), 3008 (2018).ADS 
PubMed 
PubMed Central 

Google Scholar 
Conring, C. M., Brautigam, K., Grisham, B. A., Collins, D. P. & Conway, W. C. Identifying the migratory strategy of the Lower Colorado River Valley population of Greater Sandhill Cranes. Avian Conserv. Ecol. 14(1), 11 (2019).
Google Scholar 
Imlay, T. L., Saldanha, S. & Taylor, P. D. The fall migratory movements of Bank Swallows, Riparia riparia: Fly-and-forage migration?. Avian Conserv. Ecol. 15(1), 2 (2020).
Google Scholar 
Piersma, T. Hop, skip, or jump? Constraints on migration of arctic waders by feeding, fattening, and flight speed. Limosa 60, 185–194 (1987).
Google Scholar 
Warnock, N. Stopping vs. staging: The difference between a hop and a jump. J. Avian Biol. 41(6), 621–626 (2010).
Google Scholar 
Gomez, C. et al. Fuel loads acquired at a stopover site influence the pace of intercontinental migration in a boreal songbird. Sci. Rep. 7(1), 3405 (2017).ADS 
PubMed 
PubMed Central 

Google Scholar 
Tottrup, A. P. et al. The annual cycle of a trans-equatorial Eurasian-African passerine migrant: different spatio-temporal strategies for autumn and spring migration. Proc. Biol. Sci. 279(1730), 1008–1016 (2012).PubMed 

Google Scholar 
Lisovski, S. et al. Inherent limits of light-level geolocation may lead to over-interpretation. Curr. Biol. 28(3), R99–R100 (2018).CAS 
PubMed 

Google Scholar 
Buler, J. J., Moore, F. R. & Woltmann, S. A multi-scale examination of stopover habitat use by birds. Ecology 88(7), 1789–1802 (2007).PubMed 

Google Scholar 
Loon, A. V. et al. Migratory stopover timing is predicted by breeding latitude, not habitat quality, in a long-distance migratory songbird. J. Ornithol. 158(3), 745–752 (2017).
Google Scholar 
Norevik, G. et al. Wind-associated detours promote seasonal migratory connectivity in a flapping flying long-distance avian migrant. J. Anim. Ecol. 89(2), 635–646 (2020).PubMed 

Google Scholar 
Norevik, G., Åkesson, S. & Hedenström, A. Migration strategies and annual space-use in an Afro-Palaearctic aerial insectivore—The European nightjar Caprimulgus europaeus. J. Avian Biol. 48(5), 738–747 (2017).
Google Scholar 
Cresswell, B. & Edwards, D. Geolocators reveal wintering areas of European Nightjar (Caprimulgus europaeus). Bird Study 60(1), 77–86 (2013).
Google Scholar 
Jacobsen, L. B. et al. Annual spatiotemporal migration schedules in three larger insectivorous birds: European nightjar, common swift and common cuckoo. Anim. Biotelem. 5(1), 1–11 (2017).
Google Scholar 
Liechti, F. & Bruderer, B. The relevance of wind for optimal migration theory. J. Avian Biol. 29(4), 561–568 (1998).
Google Scholar 
Schmaljohann, H., Bruderer, B. & Liechti, F. Sustained bird flights occur at temperatures far beyond expected limits. Anim. Behav. 76(4), 1133–1138 (2008).
Google Scholar 
Schmaljohann, H., Liechti, F. & Bruderer, B. Trans-Sahara migrants select flight altitudes to minimize energy costs rather than water loss. Behav. Ecol. Sociobiol. 63(11), 1609–1619 (2009).
Google Scholar 
Sjöberg, S. et al. Extreme altitudes during diurnal flights in a nocturnal songbird migrant. Science 372, 646–648 (2021).ADS 
PubMed 

Google Scholar 
Bruderer, B., Peter, D. & Korner-Nievergelt, F. Vertical distribution of bird migration between the Baltic Sea and the Sahara. J. Ornithol. 159(2), 315–336 (2018).
Google Scholar  More

Global patterns of ARG distributionWe used a set of 4572 metagenomic samples to illustrate the global patterns of ARG distribution (Supplementary Data 1). These samples were collected from six types of habitats: air, aquatic, terrestrial, engineered, humans and other hosts (Fig. 1a and Supplementary Data 1). From these samples, we identified a total of 2561 ARGs that conferred resistance to 24 drug classes of antibiotics based on the Comprehensive Antibiotic Research Database (CARD). Of these, 2401 were genes conferring resistance to only one drug class, and 160 conferred resistances to multiple drug classes (Supplementary Data 2). Twenty-five ARGs were found in more than 75% samples, however, the frequency of most ARGs (2313/2561) were More

Jeltsch, F. et al. Integrating movement ecology with biodiversity research—Exploring new avenues to address spatiotemporal biodiversity dynamics. Mov. Ecol. 1, 6 (2013).PubMed 
PubMed Central 

Google Scholar 
Dingle, H. Migration: The Biology of Life on the Move Migration (Oxford University Press, 2014).Joly, K. et al. Longest terrestrial migrations and movements around the world. Sci. Rep. 9, 15333 (2019).ADS 
PubMed 
PubMed Central 

Google Scholar 
Lundberg, J. & Moberg, F. Mobile link organisms and ecosystem functioning: Implications for ecosystem resilience and management. Ecosystems 6, 0087–0098 (2003).
Google Scholar 
Bauer, S. & Hoye, B. J. Migratory animals couple biodiversity and ecosystem functioning worldwide. Science 344, 1242552 (2014).CAS 
PubMed 

Google Scholar 
Nifong, J. C., Layman, C. A. & Silliman, B. R. Size, sex and individual-level behaviour drive intrapopulation variation in cross-ecosystem foraging of a top-predator. J. Anim. Ecol. 84, 35–48 (2015).PubMed 

Google Scholar 
Giroux, M.-A. et al. Benefiting from a migratory prey: Spatio-temporal patterns in allochthonous subsidization of an arctic predator. J. Anim. Ecol. 81, 533–542 (2012).PubMed 

Google Scholar 
Allen, A. M. & Singh, N. J. Linking movement ecology with wildlife management and conservation. Front. Ecol. Evol. 3, 155 (2016).
Google Scholar 
Bunnefeld, N. et al. A model-driven approach to quantify migration patterns: Individual, regional and yearly differences. J. Anim. Ecol. 80, 466–476 (2011).PubMed 

Google Scholar 
Teitelbaum, C. S. & Mueller, T. Beyond migration: Causes and consequences of nomadic animal movements. Trends Ecol. Evol. 34, 569–581 (2019).PubMed 

Google Scholar 
Berg, J. E., Hebblewhite, M., St. Clair, C. C. & Merrill, E. H. Prevalence and mechanisms of partial migration in ungulates. Front. Ecol. Evol. 7, 325 (2019).
Google Scholar 
Avgar, T., Street, G. & Fryxell, J. M. On the adaptive benefits of mammal migration. Can. J. Zool. 92, 481–490 (2014).
Google Scholar 
Barbour, M. G. & Billings, W. D. North American Terrestrial Vegetation (Cambridge University Press, 2000).
Google Scholar 
Smith, S. L., Throop, J. & Lewkowicz, A. G. Recent changes in climate and permafrost temperatures at forested and polar desert sites in northern Canada. Can. J. Earth Sci. 49, 914–924 (2012).ADS 

Google Scholar 
Lévesque, E. Plant Distribution and Colonization in Extreme Polar Deserts, Ellesmere Island, Canada (University of Toronto, 1997).
Google Scholar 
Bliss, L. C., Svoboda, J. & Bliss, D. I. Polar deserts, their plant cover and plant production in the Canadian High Arctic. Holarctic Ecol. 7, 305–324 (1984).
Google Scholar 
Berteaux, D. et al. Effects of changing permafrost and snow conditions on tundra wildlife: Critical places and times. Arctic Sci. 3, 65–90 (2017).
Google Scholar 
Duchesne, D., Gauthier, G. & Berteaux, D. Habitat selection, reproduction and predation of wintering lemmings in the Arctic. Oecologia 167, 967–980 (2011).ADS 
PubMed 

Google Scholar 
Fuglei, E., Blanchet, M.-A., Unander, S., Ims, R. A. & Pedersen, Å. Ø. Hidden in the darkness of the Polar night: A first glimpse into winter migration of the Svalbard rock ptarmigan. Wildl. Biol. 2017, SP1 (2017).
Google Scholar 
Schmidt, N. M. et al. Ungulate movement in an extreme seasonal environment: Year-round movement patterns of high-arctic muskoxen. Wildl. Biol. 22, 253–267 (2016).
Google Scholar 
Berteaux, D. & Lai, S. Walking on water: Terrestrial mammal migrations in the warming Arctic. Anim. Migr. 8, 65–73 (2021).
Google Scholar 
Gnanadesikan, G. E., Pearse, W. D. & Shaw, A. K. Evolution of mammalian migrations for refuge, breeding, and food. Ecol. Evol. 7, 5891–5900 (2017).PubMed 
PubMed Central 

Google Scholar 
Best, T. L. & Henry, T. H. Lepus arcticus. Mamm. Species 1–9 (1994).Dalerum, F. et al. Exploring the diet of arctic wolves (Canis lupus arctos) at their northern range limit. Can. J. Zool. 96, 277–281 (2018).
Google Scholar 
Mech, L. D. Annual arctic wolf pack size related to arctic hare numbers. Arctic 60, 309–311 (2007).
Google Scholar 
Small, R. J., Keith, L. B. & Barta, R. M. Demographic responses of Arctic hares Lepus arcticus placed on two predominantly forested islands in Newfoundland. Ecography 15, 161–165 (1992).
Google Scholar 
Small, R. J., Keith, L. B. & Barta, R. M. Dispersion of introduced arctic hares (Lepus arcticus) on islands off Newfoundland’s south coast. Can. J. Zool. 69, 2618–2623 (1991).
Google Scholar 
Hearn, B. J., Keith, L. B. & Rongstad, O. J. Demography and ecology of the arctic hare (Lepus arcticus) in southwestern Newfoundland. Can. J. Zool. 65, 852–861 (1987).
Google Scholar 
Harper, F. The Mammals of Keewatin Vol. 12 (Miscellaneaous Publications, Museum of Natural History, University of Kansas, 1956).
Google Scholar 
Dalerum, F. et al. Spatial variation in Arctic hare (Lepus arcticus) populations around the Hall Basin. Polar Biol. 40, 2113–2118 (2017).
Google Scholar 
Fraser, K. C. et al. Tracking the conservation promise of movement ecology. Front. Ecol. Evol. 6, 150 (2018).
Google Scholar 
CAFF. Arctic Biodiversity Assessment. Status and trends in Arctic biodiversity. Conservation of Arctic Flora and Fauna, Akureyri (2013).Desjardins, É. et al. Survey of the vascular plants of Alert (Ellesmere Island, Canada), a polar desert at the northern tip of the Americas. CheckList 17, 181–225 (2021).
Google Scholar 
Keith, L. B., Meslow, E. C. & Rongstad, O. J. Techniques for snowshoe hare population studies. J. Wildl. Manag. 32, 801–812 (1968).
Google Scholar 
Davidson, S. C. et al. Ecological insights from three decades of animal movement tracking across a changing Arctic. Science 370, 712–715 (2020).ADS 
CAS 
PubMed 

Google Scholar 
Wikelski, M., Davidson, S. C. & Kays, R. Movebank: Archive, analysis and sharing of animal movement data. Hosted by the Max Planck Institute of Animal Behavior. http://www.movebank.org (2021).Berteaux, D. Data from: Study ‘Arctic hare Alert—Argos tracking’. MoveBank Data Repository https://doi.org/10.5441/001/1.d5d912c4 (2021).Article 

Google Scholar 
R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/ (2021).Christin, S., St-Laurent, M.-H. & Berteaux, D. Evaluation of Argos telemetry accuracy in the High-Arctic and implications for the estimation of home-range size. PLoS One 10, e0141999 (2015).PubMed 
PubMed Central 

Google Scholar 
QGIS Association. QGIS Geographic Information System (2021).Harris, S. et al. Home-range analysis using radio-tracking data? A review of problems and techniques particularly as applied to the study of mammals. Mamm. Rev. 20, 97–123 (1990).
Google Scholar 
Le Corre, M., Dussault, C. & Côté, S. D. Detecting changes in the annual movements of terrestrial migratory species: Using the first-passage time to document the spring migration of caribou. Mov. Ecol. 2, 19 (2014).PubMed 
PubMed Central 

Google Scholar 
Nicholson, K. L., Arthur, S. M., Horne, J. S., Garton, E. O. & Vecchio, P. A. D. Modeling caribou movements: Seasonal ranges and migration routes of the central Arctic herd. PLoS One 11, e0150333 (2016).PubMed 
PubMed Central 

Google Scholar 
Nelson, M. E., Mech, L. D. & Frame, P. F. Tracking of white-tailed deer migration by global positioning system. J. Mammal. 85, 505–510 (2004).
Google Scholar 
Singh, N. J. & Ericsson, G. Changing motivations during migration: Linking movement speed to reproductive status in a migratory large mammal. Biol. Lett. 10, 20140379 (2014).PubMed 
PubMed Central 

Google Scholar 
Jakes, A. F. et al. Classifying the migration behaviors of pronghorn on their northern range. J. Wildl. Manag. 82, 1229–1242 (2018).
Google Scholar 
Bates, D., Maechler, M., Bolker, B. & Walker, S. lme4: Linear mixed-effects models using Eigen and S4. (2015).Duong, T. ks: Kernel density estimation and kernel discriminant analysis for multivariate data in R. J. Stat. Softw. 21, 1–16 (2007).
Google Scholar 
Gitzen, R. A., Millspaugh, J. J. & Kernohan, B. J. Bandwidth selection for fixed-kernel analysis of animal utilization distributions. J. Wildl. Manag. 70, 1334–1344 (2006).
Google Scholar 
Austin, R. E. et al. Patterns of at-sea behaviour at a hybrid zone between two threatened seabirds. Sci. Rep. 9, 14720 (2019).ADS 
PubMed 
PubMed Central 

Google Scholar 
Gillis, E. A. & Krebs, C. J. Natal dispersal of snowshoe hares during a cyclic population increase. J. Mammal. 80, 933–939 (1999).
Google Scholar 
Dahl, F. & Willebrand, T. Natal dispersal, adult home ranges and site fidelity of mountain hares (Lepus timidus) in the boreal forest of Sweden. Wildl. Biol. 11, 309–317 (2005).
Google Scholar 
Angerbjörn, A. & Flux, J. E. C. Lepus timidus. Mamm. Species 495, 1–11 (1995).
Google Scholar 
Smith, G. W., Stoddart, L. C. & Knowlton, F. F. Long-distance movements of black-tailed jackrabbits. J. Wildl. Manag. 66, 463 (2002).
Google Scholar 
Cote, J. et al. Behavioural synchronization of large-scale animal movements—Disperse alone, but migrate together?. Biol. Rev. 92, 1275–1296 (2017).PubMed 

Google Scholar 
Bauer, S., McNamara, J. M. & Barta, Z. Environmental variability, reliability of information and the timing of migration. Proc. R. Soc. B 287, 20200622 (2020).PubMed 
PubMed Central 

Google Scholar 
Couzin, I. D. Collective animal migration. Curr. Biol. 28, R976–R980 (2018).CAS 
PubMed 

Google Scholar 
Lai, S. et al. Unsuspected mobility of Arctic hares revealed by longest journey ever recorded in a lagomorph. Ecology 103(3), e3620 https://doi.org/10.1002/ecy.3620 (2022).PubMed 

Google Scholar 
Abrahms, B. et al. Suite of simple metrics reveals common movement syndromes across vertebrate taxa. Mov. Ecol. 5, 12 (2017).PubMed 
PubMed Central 

Google Scholar 
Chapman, B. B., Brönmark, C., Nilsson, J. -Å. & Hansson, L.-A. The ecology and evolution of partial migration. Oikos 120, 1764–1775 (2011).
Google Scholar 
Singh, N. J., Börger, L., Dettki, H., Bunnefeld, N. & Ericsson, G. From migration to nomadism: Movement variability in a northern ungulate across its latitudinal range. Ecol. Appl. 22, 2007–2020 (2012).PubMed 

Google Scholar 
Bastille-Rousseau, G. et al. Flexible characterization of animal movement pattern using net squared displacement and a latent state model. Mov. Ecol. 4, 15 (2016).PubMed 
PubMed Central 

Google Scholar 
Mueller, T. & Fagan, W. F. Search and navigation in dynamic environments—From individual behaviors to population distributions. Oikos 117, 654–664 (2008).
Google Scholar 
Krebs, C. J., Boonstra, R. & Boutin, S. Using experimentation to understand the 10-year snowshoe hare cycle in the boreal forest of North America. J. Anim. Ecol. 87, 87–100 (2018).PubMed 

Google Scholar 
Reid, N. & Harrison, A. Post-release GPS tracking of hand-reared Irish hare Lepus timidus hibernicus leverets, Slemish, Co. Antrim, Northern Ireland. J. Wildl. Rehabil. 31, 25 (2011).
Google Scholar 
Weterings, M. J. A. et al. Strong reactive movement response of the medium-sized European hare to elevated predation risk in short vegetation. Anim. Behav. 115, 107–114 (2016).
Google Scholar 
Krebs, C. J., Boutin, S. & Boonstra, R. Ecosystem Dynamics of the Boreal Forest: The Kluane Project (Oxford University Press, 2001).
Google Scholar 
Feierabend, D. & Kielland, K. Movements, activity patterns, and habitat use of snowshoe hares (Lepus americanus) in interior Alaska. J. Mammal. 95, 525–533 (2014).
Google Scholar 
Levänen, R., Pohjoismäki, J. L. O. & Kunnasranta, M. Home ranges of semi-urban brown hares (Lepus europaeus) and mountain hares (Lepus timidus) at northern latitudes. Ann. Zool. Fenn. 56, 107–120 (2019).
Google Scholar 
Nathan, R. et al. A movement ecology paradigm for unifying organismal movement research. Proc. Natl. Acad. Sci. U.S.A. 105, 19052–19059 (2008).ADS 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Abrahms, B. et al. Emerging perspectives on resource tracking and animal movement ecology. Trends Ecol. Evol. 36, 308–320 (2021).PubMed 

Google Scholar 
France, R. L. The Lake Hazen trough: A late winter oasis in a polar desert. Biol. Conserv. 63, 149–151 (1993).
Google Scholar 
Jenkins, D. A., Campbell, M., Hope, G., Goorts, J. & McLoughlin, P. Recent trends in abundance of Peary caribou (Rangifer tarandus pearyi) and muskoxen (Ovibos moschatus) in the Canadian Arctic Archipelago, Nunavut 233.Mech, L. Proportion of calves and adult muskoxen, Ovibos moschatus killed by gray wolves, Canis lupus, in July on Ellesmere Island (USGS Northern Prairie Wildlife Research Center, 2010).
Google Scholar 
Gunn, A., Miller, F., Barry, S. & Buchan, A. A near-total decline in caribou on Prince of Wales, Somerset, and Russell Islands, Canadian Arctic. Arctic 59, 1–13 (2006).
Google Scholar 
Edwards, J. Diet shifts in moose due to predator avoidance. Oecologia 60, 185–189 (1983).ADS 
PubMed 

Google Scholar 
Gustine, D. D., Parker, K. L., Lay, R. J., Gillingham, M. P. & Heard, D. C. Calf survival of woodland caribou in a multi-predator ecosystem. Wildl. Monogr. 165, 1–32 (2006).
Google Scholar 
Klein, D. & Bay, C. Diet selection by vertebrate herbivores in the High Arctic of Greenland. Ecography 14, 152–155 (1991).
Google Scholar 
Parks Canada. Resource Description and Analysis—Ellesmere Island National Park Reserve Vol. 1 (Natural Resource Conservation Section, Parks Canada, Department of Canadian Heritage, 1994).
Google Scholar 
Parks Canada. Quttinirpaaq National Park of Canada: Management plan 76. https://www.pc.gc.ca/en/pn-np/nu/quttinirpaaq/info/index/gestion-management-2009 (2009).Winkler, D. W. et al. Cues, strategies, and outcomes: How migrating vertebrates track environmental change. Mov. Ecol. 2, 10 (2014).
Google Scholar 
Robinson, R. et al. Travelling through a warming world: Climate change and migratory species. Endang. Species Res. 7, 87–99 (2009).ADS 

Google Scholar  More

Alerstam, T., Hedenström, A. & Åkesson, S. Long‐distance migration: evolution and determinants. Oikos 103, 247–260 (2003).Article 

Google Scholar 
Newton, I. The migration ecology of birds (Elsevier, London, 2008).Putman, N. F. et al. An inherited magnetic map guides ocean navigation in juvenile Pacific salmon. Curr. Biol. 24, 446–450 (2014).CAS 
Article 

Google Scholar 
Jesmer, B. R. et al. Is ungulate migration culturally transmitted? Evidence of social learning from translocated animals. Science 361, 1023–1025 (2018).ADS 
CAS 
Article 

Google Scholar 
Milner-Gulland, E. J., Fryxell, J. M. & Sinclair, A. R. (Eds.) Animal migration: a synthesis (Oxford University Press, New York, 2011).Conradt, L. & Roper, T. J. Consensus decision making in animals. Trends Ecol. Evol. 20, 449–456 (2005).Article 

Google Scholar 
Couzin, I. D., Krause, J., Franks, N. R. & Levin, S. A. Effective leadership and decision-making in animal groups on the move. Nature 433, 513–516 (2005).ADS 
CAS 
Article 

Google Scholar 
Vansteelant, W. M. G., Kekkonen, J. & Byholm, P. Wind conditions and geography shape the first outbound migration of juvenile honey buzzards and their distribution across sub-Saharan Africa. Proc. R. Soc. B 284, 20170387 (2017).Article 

Google Scholar 
Flack, A., Nagy, M., Fiedler, W., Couzin, I. D. & Wikelski, M. From local collective behavior to global migratory patterns in white storks. Science 360, 911–914 (2018).ADS 
CAS 
Article 

Google Scholar 
Chernetsov, N., Berthold, P. & Querner, U. Migratory orientation of first-year white storks (Ciconia ciconia): inherited information and social interactions. J. Exp. Biol. 207, 937–943 (2004).Article 

Google Scholar 
Mueller, T., O’Hara, R. B., Converse, S. J., Urbanek, R. P. & Fagan, W. F. Social learning of migratory performance. Science 341, 999–1002 (2013).ADS 
CAS 
Article 

Google Scholar 
Whiten, A. Cultural evolution in animals. Annu. Rev. Ecol. Evol. Syst. 50, 27–48 (2019).Article 

Google Scholar 
Whitehead, H. & Rendell, L. The Cultural Lives of Whales and Dolphins (Chicago University Press, Chicago, 2015).Franks, N. R. & Richardson, T. Teaching in tandem-running ants. Nature 439, 153–153 (2006).ADS 
CAS 
Article 

Google Scholar 
Thornton, A. & McAuliffe, K. Teaching in wild meerkats. Science 313, 227–229 (2006).ADS 
CAS 
Article 

Google Scholar 
Cramp, S. (Ed.) The birds of the Western Palearctic. Vol. IV. Terns to woodpeckers (Oxford University Press, New York, 1985).Méndez, V. et al. Paternal effects in the initiation of migratory behaviour in birds. Sci. Rep. 11, 2782 (2021).ADS 
Article 

Google Scholar 
Olson, V. A., Liker, A., Freckleton, R. P. & Székely, T. Parental conflict in birds: comparative analyses of offspring development, ecology and mating opportunities. Proc. R. Soc. B 275, 301–307 (2008).CAS 
Article 

Google Scholar 
Ledwoń, M. & Neubauer, G. Offspring desertion and parental care in the Whiskered Tern Chlidonias hybrida. Ibis 159, 860–872 (2017).Article 

Google Scholar 
Arnqvist, G. & Rowe, L. Sexual conflict (Princeton University Press, New York, 2005).Goodenough, K. S. & Patton, R. T. Satellite telemetry reveals strong fidelity to migration routes and wintering grounds for the gull-billed tern (Gelochelidon nilotica). Waterbirds 42, 400–410 (2019).Article 

Google Scholar 
Gu, Z. et al. Climate-driven flyway changes and memory-based long-distance migration. Nature 591, 259–264 (2021).ADS 
CAS 
Article 

Google Scholar 
Baert, J. M. et al. Resource predictability drives interannual variation in migratory behavior in a long-lived bird. Behav. Ecol. arab132, https://doi.org/10.1093/beheco/arab132 (2021).Papageorgiou, D. & Farine, D. R. Group size and composition influence collective movement in a highly social terrestrial bird. eLife 9, e59902 (2020).CAS 
Article 

Google Scholar 
Caro, T. M. & Hauser, M. D. Is there teaching in nonhuman animals? Q. Rev. Biol. 67, 151–174 (1992).CAS 
Article 

Google Scholar 
Thornton, A. & Raihani, N. J. The evolution of teaching. Anim. Behav. 75, 1823–1836 (2008).Article 

Google Scholar 
Riedman, M. L. The evolution of alloparental care and adoption in mammals and birds. Q. Rev. Biol. 57, 405–435 (1982).Article 

Google Scholar 
Sheppard, C. E. et al. Decoupling of genetic and cultural inheritance in a wild mammal. Curr. Biol. 28, 1846–1850 (2018).CAS 
Article 

Google Scholar 
Åkesson, S. & Helm, B. Endogenous programs and flexibility in bird migration. Front. Ecol. Evol. 8, 1–20 (2020).Article 

Google Scholar 
Sasaki, T. & Biro, D. Cumulative culture can emerge from collective intelligence in animal groups. Nat. Commun. 8, 1–6 (2017).ADS 
Article 

Google Scholar 
Whiten, A., Ayala, F. J., Feldman, M. W. & Laland, K. N. The extension of biology through culture. Proc. Natl Acad. Sci. USA 114, 7775–7781 (2017).CAS 
Article 

Google Scholar 
Aplin, L. M. Culture and cultural evolution in birds: a review of the evidence. Anim. Behav. 147, 179–187 (2019).Article 

Google Scholar 
Laland, K. N., Toyokawa, W. & Oudman, T. Animal learning as a source of developmental bias. Evol. Dev. 22, 126–142 (2020).Article 

Google Scholar 
Sergio, F. et al. Individual improvements and selective mortality shape lifelong migratory performance. Nature 515, 410–413 (2014).ADS 
CAS 
Article 

Google Scholar 
Guttal, V. & Couzin, I. D. Social interactions, information use, and the evolution of collective migration. Proc. Natl Acad. Sci. USA 107, 16172–16177 (2010).ADS 
CAS 
Article 

Google Scholar 
Oudman, T. et al. Young birds switch but old birds lead: how barnacle geese adjust migratory habits to environmental change. Front. Ecol. Evol. 7, 106–120 (2020).Article 

Google Scholar 
Pearson, R. G. et al. Life history and spatial traits predict extinction risk due to climate change. Nat. Clim. Chang 4, 217–221 (2014).ADS 
Article 

Google Scholar 
Vickery, J. A. The decline of Afro-Palaearctic migrants and an assessment of potential causes. Ibis 156, 1–22 (2014).Article 

Google Scholar 
Thaxter, C. B. et al. A trial of three harness attachment methods and their suitability for long-term use on Lesser Black-backed Gulls and Great Skuas. Ringing Migr. 29, 65–76 (2014).Article 

Google Scholar 
Byholm, P., Beal, M., Isaksson, N., Lötberg, U. & Åkesson, S. Data from: paternal transmission of migration knowledge in a long-distance bird migrant. Movebank Data Repos. https://doi.org/10.5441/001/1.352qf1cv (2022).Article 

Google Scholar 
R Core Team. R: A language and environment for statistical computing. (R Foundation for Statistical Computing, Vienna, 2020). https://www.R-project.org/. More

This is the first study analyzing mandible shape in both mink species and, together with a previous study on their cranial shape38, it has revealed how small morphological differences in highly similar species can lead to substantial biomechanical differences (see breakdown below). As with cranial shape, mandible shape in minks is influenced by the complex interaction of size and sexual dimorphism both at the inter- and intraspecific levels. However, while in cranial shape both species had divergent shape allometries and parallel interspecific sexual allometries, the opposite was true for mandible shape.Differences in mandible shape between European and American mink were summarized by PC1 (Fig. 2, Fig. S1) and can be mainly related to muscle size and jaw biomechanics (i.e., in-levers and out-levers). The relatively taller and slightly wider coronoid process of European minks suggests a relatively larger temporalis muscle, while the anteriorly expanded masseteric fossa of American mink is indicative of a relatively larger masseter complex17,22,25. The relatively enlarged angular process of European mink provides a larger attachment area for the superficial masseter, with both mink species having a distinctive fossa on the lateral side of the angular process where this muscle attaches. This angular fossa is not present in European polecats (Gálvez-López, pers. obs.), part of the sister clade to European mink41.Regarding jaw biomechanics, the particular morphology of the American mink illustrates the compromise between maximizing both bite force efficiency and increased gape. The MAs for all masticatory muscles were higher in European mink due to their relatively longer in-levers (and also shorter out-levers if measured on PC1 configurations), with the exception of the MA of the deep masseter which was considerably higher in American mink (Table S2; Fig. 1D). These findings indicate that American mink exhibit features that allow them to produce larger forces at wide gape, which is particularly useful for holding and killing terrestrial vertebrates22,42. In agreement with this, a short moment arm of the superficial masseter (as observed in American mink) has been associated with increased gape in other mammals43. It is also worth noting that low MAs for the posterior temporalis and superficial masseter have also been associated with fish capture, as they indicate a relatively longer mandible relative to the muscle in-levers, which in turn allows the mouth to close faster when trying to catch elusive prey underwater21. In contrast, the characteristic features of European mink are indicative of stronger bites at the carnassials, which would allow them to cut through relatively tougher tissues and also to crush harder objects (e.g. shells of aquatic prey). Favoring carnassial over anterior bites could also be advantageous to feeding on fish. Mink catch fish underwater by grabbing them by the fins or back with their anterior teeth, and then dragging them to the surface where they are processed using cheek (carnassial) bites (Gálvez-López, pers. obs.).In our previous study on cranial shape in mink38, morphological differences between both species indicated relatively larger muscle volumes overall in the American mink (temporalis: more developed sagittal and nuchal crests, narrower braincase; masseter: longer and more curved zygomatic arches, larger infratemporal fossa), which suggested that bite forces both at the anterior dentition and at the carnassials were larger in this species. However, when combined with the MA results from this study on mandible shape, the relationship between muscle volume and force production becomes less straightforward. In the case of the European mink, the relatively smaller temporalis has a larger attachment site on the mandible (i.e., a broader and taller coronoid) and becomes more efficient (i.e., has higher MAs) due to the relatively longer in-lever. Similarly, in the American mink the effective length of the superficial masseter is increased by the marked curvature of the zygomatic arches, which mitigates the dorsal displacement of the angular process. However, the efficiency of the relatively larger temporalis is diminished by a smaller coronoid (i.e., reduced attachment area and shorter in-levers). The remaining differences in cranial morphology align with differences in mandible shape. Namely, the relatively broader zygomatic arches of the European mink support a strong superficial masseter, while the larger infratemporal fossae of American mink account for their enlarged deep masseter. On a final note, another finding common to both cranial and mandible shape was the relatively larger crushing dentition of American mink.Thus, after combining the results of cranial and mandible shape, it appears that, while the characteristic features of European mink indeed allow stronger carnassial bites, American mink present morphological indicators of both strong killing bites at wide gapes and powerful carnassial bites with a marked crushing component.The allometric effect on mandible size common to both species was represented by PC2 (Fig. 2, Fig. S3), which complements the common allometric trend recovered for both mink species in cranial shape38. The relative expansion of the masseteric fossa and the angular process with increasing size suggests that larger mink present a larger masseter complex. However, most of the allometric shape changes are related to muscle in-levers and out-levers. With increasing size, the length of both the out-lever at the anterior teeth and the in-levers of its related muscles (anterior temporalis, deep masseter) increases (Table S2), but the in-levers scale faster than the out-lever (Table S2). Thus, the mechanical advantages of both muscles at the anterior teeth also increase with size (Table S2), indicating that larger mink have markedly stronger and more efficient killing bites (particularly true for the deep masseter, which also becomes larger with size). This, together with their relatively larger anterior dentition (both in the mandible and the cranium) and taller anterior corpus, can be related to feeding on larger prey as size increases (i.e., stronger bites to perforate tougher skulls and hold onto stronger struggling prey, which would also require more robust teeth and corpora to resist the stresses placed on them). Similar features have been described for felids18, which also kill prey in this way22,32.Note, however, that one of the shape changes along PC2 does not accurately reflect the common allometric pattern: the lever arm of the superficial masseter, which slightly decreases along PC2 (Fig. 2; Table S2) and results in a decrease of the mechanical advantage of the superficial masseter and hence bite force at the carnassials along this axis (Table S2). In contrast, this lever arm significantly increases with size in the original specimens (Table S2), in agreement with the common allometric trend in cranial shape suggesting stronger bites at all teeth with increasing size38. A likely explanation for this phenomenon is that the common allometric trend is being confounded with interspecific shape differences, as American mink have significantly shorter superficial masseter in-levers than European mink (Fig. 1F; Table S2) yet their males are significantly larger than all other specimens (Fig. 1A). As mentioned above, the relative decrease in MA might reflect the trade-off between producing strong bite forces at the anterior teeth and having a wider gape to capture larger prey43, both of which are heavily supported by other morphological features in this common allometric trend.Sexual dimorphism in mandible shape was significant both within each species, and when grouping sexes from both species together. In her study of Palearctic mustelids, Romaniuk28 also found evidence for interspecific sexual dimorphism in mandible shape, but within species it was only significant for the Siberian weasel (Mustela sibirica). The different results for the European mink in that study might be related to its smaller sample. Note, however, that Hernández-Romero et al.40 did not find evidence for sexual dimorphism in mandible shape within Neotropical otters (Lontra longicaudis) even though their sample sizes were equivalent to those in the present study.Overall, the results of the present study reveal that mandible shape differences between males and females are the consequence of a complex interaction between sex and size at both inter- and intraspecific levels. For instance, each sex in each species has a mandible shape significantly different from each other (Table 1), but allometric shape changes within each of them are similar (except maybe female American mink; Fig. S5A). Additionally, while trajectory analysis indicates that the degree of sexual dimorphism in mandible shape is similar within each species, the specific differences between sexes are different in each species (i.e., same magnitude, different orientation; Table 2, Fig. S5B). While at the interspecific level, male and female mandible shapes change differently with increasing size even though the change per unit size is similar in both sexes (Tables 1, 2; Fig. S5C,D), and some of the allometric changes are common to both species and sexes (see section above; PC2 in Fig. 2). Finally, another set of shape changes related to sexual dimorphism and common to both species are those related to sexual dimorphism in mandible size, illustrated by PC3 (Figs. 2, Fig. S4).Shape changes related to sexual dimorphism in size are represented along PC3 and can be related to an overall increase in bite force (i.e., at all teeth), as higher scores on this axis correspond to increased muscle attachment areas and longer in-levers (taller and wider coronoid, anteriorly expanded masseteric fossa, ventrally expanded angular process), shorter out-levers (particularly at the anterior teeth), and a more robust corpus (dorsoventrally and mediolaterally expanded). This interpretation of shape changes along PC3 is supported by the results of the ANOVAs on the lever arms and MAs measured on the PC3 configurations (Table S2). These variables were only related to sex and size, with female mink having longer out-levers and male mink presenting longer in-levers and higher MAs, while out-levers decreased with increasing size and in-levers and MAs increased in both sexes (no significant interaction between sex and size indicates parallel allometric trajectories in both sexes). This trend is consistent with the common sexual allometry described for cranial shape, which suggested that larger males have bigger masticatory muscles than smaller females and thus produce higher bite forces38. Additionally, even though the relative length of the toothrow decreases, the size of the canine markedly increases and there is no change in molar size or the relative proportions in its shearing and crushing regions. Although this might be interpreted as reinforcing the canines to cope with killing larger prey while maintaining an otherwise similar dietary regime20, it is worth noting that larger canines have been long described as a feature of sexual size dimorphism in mustelids19,44,45.In terms of interspecific differences in sexual allometry, with increasing size the following shape changes were observed in females but not in males (Fig. S5C): a dorsoventrally more robust corpus, a ventral expansion of the angular process, longer in-levers for all masticatory muscles, larger incisors, and an increase in the shearing portion of m1 relative to the crushing portion. Most of these shape changes are similar to those described for PC3, which suggests that the female interspecific allometry bridges the bite force gap caused by sexual dimorphism in size. The changes to the female dentition suggest a shift in diet from crushing tough food items (e.g. aquatic invertebrates) towards slicing meat, which makes sense since these changes occur simultaneously with the common allometric trend (related to improved capabilities for killing larger vertebrate prey). However, as noted earlier, the increased shearing component is also advantageous for a piscivorous diet. Shape changes in male mandibles not observed in females seem to emphasize the common allometric trend (i.e., stronger killing bite at larger gapes) (Fig. S5D): a wider coronoid process for more muscle attachment, a dorsally displaced angular process to allow wider gapes, and mediolateral expansion of the corpus to increase its strength. Regarding their dentition, the opposite trend to females was observed (i.e., slightly smaller anterior teeth and a longer crushing molar portion), suggesting a larger durophagous component in the diet of larger males.As expected, variation in mandible shape could be linked to potential dietary differences between European and American mink, and also between sexes. In summary, the results of the present study show that:

American mink are better equipped for preying on terrestrial vertebrates, as they can achieve relatively larger gapes and their mandibles are able to produce larger forces during the killing bite (i.e., at the anterior teeth and with an open mouth).

European mink, on the other hand, can produce relatively stronger bites at the carnassials, suggesting that they rely more on tougher prey and/or fish.

Regardless of species and sex, morphological features in larger mink demonstrate increased capabilities for feeding on larger terrestrial prey (stronger killing bites and more robust anterior teeth and corpora to resist the stresses caused by struggling prey).

Due to their larger size, male mink of both species have stronger bites than females at both the anterior teeth and the carnassials. However, with increasing size, females bridge the gap by developing relatively stronger bites overall while shifting their diet from tougher or harder prey (probably aquatic invertebrates) towards less mechanically demanding food items (e.g. terrestrial vertebrates and/or fish). In contrast, increasing size in males leads to even more specialization towards feeding on larger terrestrial prey while tough items become more relevant in their diets (probably crushing bones of small prey).

These findings confirm our original predictions based on previous results on cranial shape differences, but do they agree with observed dietary preferences in minks? Diet studies in American mink are numerous, and provide a wide picture of seasonal and regional variation8,11 as well as intraspecific dietary competition6,7,12. However, studies on European mink diet are scarcer9,14, particularly those comparing the sexes13. Additionally, a few studies have compared diets of sympatric European and American mink10,15. All these studies can be summarized as: A, male American mink favor medium-sized mammals and birds usually heavier than themselves; B, female American mink favor aquatic prey, but are displaced towards small mammals and birds when seasonal changes in prey availability shift the males’ diet towards aquatic prey; C, European mink favor aquatic prey, particularly fish and crayfish; but D, they are displaced towards amphibians and small mammals when sympatric with American mink. From these, our results on mandible shape variation support A and somewhat B and C, but provide no information on the interspecific competition scenario or on potential seasonal or local dietary differences. Additionally, there is no information on size-related dietary changes in either species that could validate our findings on sexual allometry in mandible shape. Thus, while mandible shape is very useful for identifying broad dietary indicators even between highly similar species, its ability to provide accurate information on their potential prey is limited.As a final note on mink diets, our previous study on cranial shape38, suggested a gradient in muscle force (and potential dietary range) from female European mink to male American mink. Based on those results and studies on social interactions between and within species35,46, we hypothesized that competition between both mink species could be displacing female European mink towards narrower and poorer diets, which could affect their survivability and ability to successfully reproduce. Fortunately, the results of the present study not only propose that there might be less overlap in diets between species and sexes than suggested by dietary studies7,10,13,15, but also indicate that dietary competition seems to be higher for small terrestrial vertebrates, not aquatic prey (on which female European mink are particularly well equipped to feed). More

Kelley, N. P. & Pyenson, N. D. Evolutionary innovation and ecology in marine tetrapods from the Triassic to the Anthropocene. Science 348, aaa3716 (2015).PubMed 

Google Scholar 
Gutarra, S. & Rahman, I. A. The locomotion of extinct secondarily aquatic tetrapods. Biol. Rev. 97, 67–98 (2022).PubMed 

Google Scholar 
Owen, R. A description of a portion of the skeleton of the Cetiosaurus, a gigantic extinct saurian reptile occurring in the oolitic formations of different portions of England. Proc. Geol. Soc. Lond. 3, 457–462 (1841).
Google Scholar 
Cope, E. On the characters of the skull in the Hadrosauridae. Proc. Natl Acad. Nat. Sci. USA 35, 97–107 (1883).
Google Scholar 
Bidar, A., Demay, L. & Thomel, G. Compsognathus corallestris, une nouvelle espèce de dinosaurien théropode du Portlandien de Canjuers (Sud-Est de la France). Annales Muséum d’Histoire Naturelle de Nice 1, 9–40 (1972).
Google Scholar 
Norell, M. A., Makovicky, P. J. & Currie, P. J. The beaks of ostrich dinosaurs. Nature 412, 873–874 (2001).ADS 
CAS 
PubMed 

Google Scholar 
Tereschenko, V. S. Adaptive features of protoceratopoids (Ornithischia: Neoceratopsia). Paleontol. J. 42, 273–286 (2008).
Google Scholar 
Lee, Y. N. et al. Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus. Nature 515, 257–260 (2014).ADS 
CAS 
PubMed 

Google Scholar 
Ibrahim, N. et al. Semiaquatic adaptations in a giant predatory dinosaur. Science 345, 1613–1616 (2014).ADS 
CAS 
PubMed 

Google Scholar 
Cau, A. et al. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature 552, 395–399 (2017).ADS 
CAS 
PubMed 

Google Scholar 
Ibrahim, N. et al. Tail-propelled aquatic locomotion in a theropod dinosaur. Nature 581, 67–70 (2020).ADS 
CAS 
PubMed 

Google Scholar 
Henderson, D. M. A buoyancy, balance and stability challenge to the hypothesis of a semi-aquatic Spinosaurus Stromer, 1915 (Dinosauria: Theropoda). PeerJ 6, e5409 (2018).PubMed 
PubMed Central 

Google Scholar 
Hone, D. W. E. & Holtz, T. R. Jr Evaluating the ecology of Spinosaurus: shoreline generalist or aquatic pursuit specialist? Palaeontol. Electronica 24, a03 (2021).
Google Scholar 
Thewissen, J. G., Cooper, L. N., Clementz, M. T., Bajpai, S. & Tiwari, B. N. Whales originated from aquatic artiodactyls in the Eocene epoch of India. Nature 450, 1190–1194 (2007).ADS 
CAS 
PubMed 

Google Scholar 
Houssaye, A. Bone histology of aquatic reptiles: what does it tell us about secondary adaptation to an aquatic life? Biol. J. Linn. Soc. 108, 3–21 (2013).
Google Scholar 
Motani, R. et al. A basal ichthyosauriform with a short snout from the Lower Triassic of China. Nature 517, 485–488 (2015).ADS 
CAS 
PubMed 

Google Scholar 
Rauhut, O. W. & Pol, D. Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs. Sci. Rep. 9, 1–9 (2019).
Google Scholar 
You, H. L. et al. A nearly modern amphibious bird from the Early Cretaceous of northwestern China. Science 312, 1640–1643 (2006).ADS 
CAS 
PubMed 

Google Scholar 
Wilson, L. E. & Chin, K. Comparative osteohistology of Hesperornis with reference to pygoscelid penguins: the effects of climate and behaviour on avian bone microstructure. R. Soc. Open Sci. 1, 140245 (2014).ADS 
PubMed 
PubMed Central 

Google Scholar 
Gatesy, S. M. & Dial, K. P. Locomotor modules and the evolution of avian flight. Evolution 50, 331–340 (1996).PubMed 

Google Scholar 
Amiot, R. et al. Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods. Geology 38, 139–142 (2010).ADS 
CAS 

Google Scholar 
Hassler, A. et al. Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs. Proc. R. Soc. B 285, 20180197 (2018).PubMed 
PubMed Central 

Google Scholar 
Larramendi, A., Paul, G. S. & Hsu, S. Y. A review and reappraisal of the specific gravities of present and past multicellular organisms, with an emphasis on tetrapods. Anat. Rec. 304, 1833–1888 (2021).
Google Scholar 
Charig, A. J. & Milner, A. C. Baryonyx, a remarkable new theropod dinosaur. Nature 324, 359–361 (1986).ADS 
CAS 
PubMed 

Google Scholar 
Schoener, T. W. The newest synthesis: understanding the interplay of evolutionary and ecological dynamics. Science 331, 426–429 (2011).ADS 
CAS 
PubMed 

Google Scholar 
Houssaye, A. “Pachyostosis” in aquatic amniotes: a review. Integr. Zool. 4, 325–340 (2009).PubMed 

Google Scholar 
Houssaye, A., Sander, M. P. & Klein, N. Adaptive patterns in aquatic amniote bone microanatomy—more complex than previously thought. Integr. Comp. Biol. 56, 1349–1369 (2016).PubMed 

Google Scholar 
Quemeneur, S., De Buffrenil, V. & Laurin, M. Microanatomy of the amniote femur and inference of lifestyle in limbed vertebrates. Biol. J. Linn. Soc. 109, 644–655 (2013).
Google Scholar 
Canoville, A., de Buffrénil, V. & Laurin, M. Microanatomical diversity of amniote ribs: an exploratory quantitative study. Biol. J. Linn. Soc. 118, 706–733 (2016).
Google Scholar 
Amson, E., de Muizon, C., Laurin, M., Argot, C. & de Buffrénil, V. Gradual adaptation of bone structure to aquatic lifestyle in extinct sloths from Peru. Proc. R. Soc. B 281, 20140192 (2014).PubMed 
PubMed Central 

Google Scholar 
Grafen, A. The phylogenetic regression. Philos. Trans. R. Soc. B 326, 119–157 (1989).ADS 
CAS 

Google Scholar 
Liem, K. F. Adaptive significance of intra-and interspecific differences in the feeding repertoires of cichlid fishes. Am. Zool. 20, 295–314 (1980).
Google Scholar 
Turner, A. H., Pol, D., Clarke, J. A., Erickson, G. M. & Norell, M. A. A basal dromaeosaurid and size evolution preceding avian flight. Science 317, 1378–1381 (2007).ADS 
CAS 
PubMed 

Google Scholar 
Voeten, D. F. et al. Wing bone geometry reveals active flight in Archaeopteryx. Nat. Commun. 9, 1319 (2018).
Google Scholar 
Houssaye, A., Martin, F., Boisserie, J. R. & Lihoreau, F. Paleoecological inferences from long bone microanatomical specializations in Hippopotamoidea (Mammalia, Artiodactyla). J. Mamm. Evol. 28, 847–870 (2021).
Google Scholar 
Amson, E. & Bibi, F. Differing effects of size and lifestyle on bone structure in mammals. BMC Biol. 19, 87 (2021).CAS 
PubMed 
PubMed Central 

Google Scholar 
Malafaia, E. et al. A new spinosaurid theropod (Dinosauria: Megalosauroidea) from the upper Barremian of Vallibona, Spain: Implications for spinosaurid diversity in the Early Cretaceous of the Iberian Peninsula. Cret. Res. 106, 104221 (2020).
Google Scholar 
Sereno, P. C. et al. A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids. Science 282, 1298–1302 (1998).ADS 
CAS 
PubMed 

Google Scholar 
Aureliano, T. et al. Semi-aquatic adaptations in a spinosaur from the Lower Cretaceous of Brazil. Cret. Res. 90, 283–295 (2018).
Google Scholar 
Barker, C. T. et al. New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae. Sci. Rep. 11, 19340 (2021).ADS 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Taquet, P. Géologie et Paléontologie du Gisement de Gadoufaoua (Aptien du Niger) (Éditions du Centre national de la Recherche Scientifique, 1976).Rayfield, E. J., Milner, A. C., Xuan, V. B. & Young, P. G. Functional morphology of spinosaur ‘crocodile-mimic’ dinosaurs. J. Vertebr. Paleontol. 27, 892–901 (2007).
Google Scholar 
Benson, R. B., Butler, R. J., Carrano, M. T. & O’Connor, P. M. Air‐filled postcranial bones in theropod dinosaurs: physiological implications and the ‘reptile’–bird transition. Biol. Rev. 87, 168–193 (2012).PubMed 

Google Scholar 
Reid, R. E. H. Zonal “growth rings” in dinosaurs. Mod. Geol. 15, 19–48 (1990).
Google Scholar 
Chinsamy, A. & Raath, M. A. Preparation of fossil bone for histological examination. Palaeont. Afr. 29, 39–44 (1992).
Google Scholar 
Griffin, C. T. et al. Assessing ontogenetic maturity in extinct saurian reptiles. Biol. Rev. 96, 470–525 (2021).
Google Scholar 
Carrano, M. T., Benson, R. B. & Sampson, S. D. The phylogeny of Tetanurae (Dinosauria: Theropoda). J. Syst. Palaeontol. 10, 211–300 (2012).
Google Scholar 
Ibrahim, N. et al. Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys 928, 1–216 (2020).PubMed 
PubMed Central 

Google Scholar 
Smyth, R. S., Ibrahim, N. & Martill, D. M. Sigilmassasaurus is Spinosaurus: a reappraisal of African spinosaurines. Cret. Res. 114, 104520 (2020).
Google Scholar 
Goloboff, P. A., Farris, J. S. & Nixon, K. C. TNT, a free program for phylogenetic analysis. Cladistics 24, 774–786 (2008).
Google Scholar 
Erickson, G. M. Assessing dinosaur growth patterns: a microscopic revolution. Trends Ecol. Evol. 20, 677–684 (2005).PubMed 

Google Scholar 
Hayashi, S. et al. Bone inner structure suggests increasing aquatic adaptations in Desmostylia (Mammalia, Afrotheria). PLoS ONE 8, e59146 (2013).ADS 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Straehl, F. R., Scheyer, T. M., Forasiepi, A. M., MacPhee, R. D. E. & Sánchez-Villagra, M. R. Evolutionary patterns of bone histology and bone compactness in xenarthran mammal long bones. PLoS ONE 8, e69275 (2013).ADS 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Houssaye, A., Tafforeau, P., de Muizon, C. & Gingerich, P. D. Transition of Eocene whales from land to sea: evidence from bone microstructure. PLoS ONE 10, e0118409 (2015).PubMed 
PubMed Central 

Google Scholar 
Girondot, M. & Laurin, M. Bone profiler: a tool to quantify, model, and statistically compare bone-section compactness profiles. J. Vertebr. Paleontol. 23, 458–461 (2003).
Google Scholar 
De Ricqlès, A. J., Padian, K., Horner, J. R., Lamm, E. T. & Myhrvold, N. Osteohistology of Confuciusornis sanctus (Theropoda: Aves). Journ. Vertebr. Paleontol. 23, 373–386 (2003).
Google Scholar 
Maddison, W. P. Mesquite: a modular system for evolutionary analysis. Evolution 62, 1103–1118 (2008).
Google Scholar 
Upham, N. S., Esselstyn, J. A. & Jetz, W. Inferring the mammal tree: species-level sets of phylogenies for questions in ecology, evolution, and conservation. PLoS Biol. 17, e3000494 (2019).CAS 
PubMed 
PubMed Central 

Google Scholar 
Simoes, T. R. et al. The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps. Nature 557, 706–709 (2018).ADS 
CAS 
PubMed 

Google Scholar 
Nesbitt, S. J. et al. The earliest bird-line archosaurs and the assembly of the dinosaur body plan. Nature 544, 484–487 (2017).ADS 
CAS 
PubMed 

Google Scholar 
Langer, M. C. et al. Untangling the dinosaur family tree. Nature 551, E1–E3 (2017).PubMed 

Google Scholar 
Brusatte, S. L., Lloyd, G. T., Wang, S. C. & Norell, M. A. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Curr. Biol. 24, 2386–2392 (2014).CAS 
PubMed 

Google Scholar 
Prum, R. O. et al. A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526, 569–573 (2015).ADS 
CAS 
PubMed 

Google Scholar 
Bapst, D. W. paleotree: an R package for paleontological and phylogenetic analyses of evolution. Methods Ecol. Evol. 3, 803–807 (2012).
Google Scholar 
Schmitz, L. & Motani, R. Nocturnality in dinosaurs inferred from scleral ring and orbit morphology. Science 332, 705–708 (2011).ADS 
CAS 
PubMed 

Google Scholar 
Motani, R. & Schmitz, L. Phylogenetic versus functional signals in the evolution of form–function relationships in terrestrial vision. Evolution 65, 2245–2257 (2011).PubMed 

Google Scholar  More