More stories

  • in

    Seasonal distribution of fish larvae in mangrove-seagrass seascapes of Zanzibar (Tanzania)

    Beck, M. W. et al. The role of near shore ecosystems as fish and shellfish nurseries. Issues Ecol. 11, 1–12 (2003).
    Google Scholar 
    De la Torre-Castro, M., Di Carlo, G. & Jiddawi, N. S. Seagrass importance for a small-scale fishery in the tropics: The need for seascape management. Mar. Poll. Bull. 83, 398–407 (2014).
    Google Scholar 
    Sheaves, M., Baker, R., Nagelkerken, I. & Connolly, R. M. True value of estuarine and coastal nurseries for fish: incorporating complexity and dynamics. Estuar. Coasts 38, 401–414 (2014).
    Google Scholar 
    Nordlund, L. M., Unsworth, R. K. F., Gullström, M. & Cullen-Unsworth, L. C. Global significance of seagrass fishery activity. Fish. Fish. 19, 399–412 (2018).
    Google Scholar 
    Kimirei, I. A., Nagelkerken, I., Griffioen, B., Wagner, C. & Mgaya, Y. D. Ontogenetic habitat use by mangrove/seagrass-associated coral reef fishes shows flexibility in time and space. Estuar. Coast. Shelf Sci. 92, 47–58 (2011).ADS 

    Google Scholar 
    Unsworth, R. K. F. et al. Structuring of Indo-Pacific fish assemblages along the mangrove-seagrass continuum. Aquat. Biol. 5, 85–95 (2009).
    Google Scholar 
    Cocheret De La Morinière, E., Pollux, B. J. A., Nagelkerken, I. & van Der Velde, G. Post-settlement life cycle migration patterns and habitat preference of coral reef fish that use seagrass and mangrove habitats as nurseries. Estuar. Coast. Shelf Sci. 55, 309–321 (2002).Berkström, C., Lindborg, R., Thyresson, M. & Gullström, M. Assessing connectivity in a tropical embayment: fish migrations and seascape ecology. Biol. Conserv. 166, 43–53 (2013).
    Google Scholar 
    Saenger, P., Gartside, D. & Funge-Smith, S. A review of mangrove and seagrass ecosystems and their linkage to fisheries and fisheries management. FAO Regional Office for Asia and the Pacific, Bangkok, Thailand, 74 (RAP Publication, 2013).King, A. J. Density and distribution of potential prey for larval fish in the main channel of a floodplain river: pelagic versus epibenthic meiofauna. River Res. Appl. 20, 883–897 (2004).
    Google Scholar 
    Carassou, L., Ponton, D., Mellin, C. & Galzin, R. Predicting the structure of larval fish assemblages by a hierarchical classification of meteorological and water column forcing factors. Coral Reefs 27, 867–880 (2008).ADS 

    Google Scholar 
    Pinho Costa, A. C., Martins Garcia, T., Pereira Paiva, B., Ximenes Neto, A. R. & de Oliveira Soares, M. Seagrass and rhodolith beds are important seascapes for the development of fish eggs and larvae in tropical coastal areas. Mar. Environ. Res. 161, 105064 (2020).Muzaki, F. K., Giffari, A. & Saptarini, D. Community structure of fish larvae in mangroves with different root types in Labuhan coastal area, Sepulu–Madura. AIP Conf. Proc. 1854, 020025 (2017).Isari, S. et al. Exploring the larval fish community of the central Red Sea with an integrated morphological and molecular approach. PLoS ONE, 12, e0182503 (2017).Levin, P. S. Fine-scale temporal variation in recruitment of a temperate demersal fish: the importance of settlement versus post-settlement loss. Oecologia 97, 124–133 (1994).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Mwaluma, J. M., Boaz Kaunda-Arara, B., Rasowo, J., Osore, M. K. & Vidar Øresland V. Seasonality in fish larval assemblage structure within marine reef National Parks in coastal Kenya. Environ. Biol. Fish. 90, 393–404 (2011).Reglero, P., Tittensor, D. P., Álvarez-Berastegui, D., Aparicio-González, A. & Worm, B. Worldwide distributions of tuna larvae: revisiting hypotheses on environmental requirements for spawning habitats. Mar. Ecol. Prog. Ser. 501, 207–224 (2014).ADS 

    Google Scholar 
    Leis, J. M. Ontogeny of behaviour in larvae of marine demersal fishes. Ichthyol. Res. 57, 325–342 (2010).
    Google Scholar 
    Tzeng, W. N. & Wang, Y. T. Hydrography and distribution dynamics of larval and juvenile fishes in the coastal waters of the Tanshui River estuary, Taiwan, with reference to estuarine larval transport. Mar. Biol. 116, 205–217 (1993).
    Google Scholar 
    Leis, J. M., Sweatman, H. P. A. & Reader, S. E. What the pelagic stages of coral reef fishes are doing out in blue water: Daytime field observations of larval behavioural capabilities. Mar. Freshw. Res. 47, 401–411 (1996).
    Google Scholar 
    Leis, J. M. & Carson-Ewart, B. M. Complex behaviour by coral-reef fish larvae in open-water and near-reef pelagic environments. Environ. Biol. Fish. 53, 259–266 (1998).
    Google Scholar 
    Leis, J. M. Are larvae of demersal fishes plankton or nekton?. Adv. Mar. Biol. 51, 57–141 (2006).PubMed 

    Google Scholar 
    Faillettaz, R., Paris, C. B. & Irisson, J. O. Larval fish swimming behavior alters dispersal patterns from marine protected areas in the North-Western Mediterranean Sea. Front. Mar. Sci. 5, 1–12 (2018).ADS 

    Google Scholar 
    Azeiteiro, U. M., Bacelar-Nicolau, L., Resende, P., Gonçalves, F. & Pereira, M. J. Larval fish distribution in shallow coastal waters off North Western Iberia (NE Atlantic). Estuar. Coast. Shelf Sci. 69, 554–566 (2006).ADS 

    Google Scholar 
    Irisson, J. O. & Lecchini, D. In situ observation of settlement behaviour in larvae of coral reef fishes at night. J. Fish Biol. 72, 2707–2713 (2008).
    Google Scholar 
    Teixeira Bonecker, F., de Castro, M. S. & Teixeira Bonecker, A. C. Larval fish assemblage in a tropical estuary in relation to tidal cycles, day/night and seasonal variations. Pan-Am. J. Aquat. Sci. 4, 239–246 (2009).Strydom, N. A. Patterns in larval fish diversity, abundance, and distribution in temperate South African estuaries. Estuar. Coasts 38, 268–284 (2014).
    Google Scholar 
    Lana, P. C. & Bernardino, A. F. (Eds). Brazilian estuaries: a benthic perspective. Brazilian Marine Biodiversity series. 212 (Springer, Cham, 2018).Donahue, M. J., Karnauskas, M., Toews, C. & Paris, C. B. Location isn’t everything: Timing of spawning aggregations optimizes larval replenishment. PLoS ONE 10, 1–15 (2015).
    Google Scholar 
    Reynalte-Tataje, D. A., Zaniboni-Filho, E., Bialetzki, A. & Agostinho, A. A. Temporal variability of fish larvae assemblages: influence of natural and anthropogenic disturbances. Neotrop. Ichthyol. 10, 837–846 (2012).
    Google Scholar 
    Somarakis, S., Tsoukali, S., Giannoulaki, M., Schismenou, E. & Nikolioudakis, N. Spawning stock, egg production and larval survival in relation to small pelagic fish recruitment. Mar. Ecol. Prog. Ser. 2018, 113–136 (2018).
    Google Scholar 
    Sampey, A., Meekan, M. G., Carleton, J. H., McKinnon, A. D. & McCormick, M. I. Temporal patterns in distributions of tropical fish larvae on the North West Shelf of Australia. Mar. Freshw. Res. 55, 473–487 (2004).
    Google Scholar 
    Rezagholinejad, S., Arshad, A., Nurul Amin, S. M. & Ehteshami, F. The influence of environmental parameters on fish larval distribution and abundance in the mangrove estuarine area of Marudu bay, Sabah, Malaysia. J. Surv. Fish. Sci. 2, 67–78 (2016).Shuai, F. et al. Temporal patterns of larval fish occurrence in a large subtropical river. PLoS ONE 11, e0156556 (2016).Nordlund, L. M. et al. Intertidal zone management in the Western Indian Ocean: assessing current status and future possibilities using expert opinions. Ambio 43, 1006–1019 (2014).PubMed 

    Google Scholar 
    De Oliveira, E. C. & Ferreira, E. J. G. Spawning areas, dispersion and microhabitats of fish larvae in the Anavilhanas Ecological Station, rio Negro, Amazonas State Brazil. Neotrop. Ichthyol. 6, 559–566 (2008).
    Google Scholar 
    Caley, M. J. et al. Recruitment and the local dynamics of open marine populations. Ann. Rev. Ecol. Syst. 27, 477–500 (1996).
    Google Scholar 
    Crochelet, E. et al. Validation of a fish larvae dispersal model with otolith data in the Western Indian Ocean and implications for marine spatial planning in data-poor regions. Ocean Coast Manag. 86, 13–21 (2013).
    Google Scholar 
    Gilroy, J. J. & Edwards, D. P. Source-sink dynamics: a neglected problem for landscape-scale biodiversity conservation in the tropics. Curr. Landsc. Ecol. Rep. 2, 51–60 (2017).
    Google Scholar 
    Little, M. C., Reay, P. J. & Grove, S. J. Distribution gradients of ichthyoplankton in an East African mangrove creek. Estuar. Coast. Shelf Sci. 26, 669–677 (1988).ADS 

    Google Scholar 
    Hedberg, P., Rybak, F. F., Gullström, M., Jiddawi, N. S. & Winder, M. Fish larvae distribution among different habitats in coastal East Africa. J. Fish Biol. 94, 29–39 (2019).CAS 
    PubMed 

    Google Scholar 
    Heylen, B. C. & Nachtsheim, D. A. Bio-telemetry as an essential tool in movement ecology and marine conservation. In: Jungblut, S., Liebich, V. & Bode, M. (Eds), YOUMARES 8–Oceans Across Boundaries: Learning From Each Other. 83–107 (Springer, 2018).Parrish, J. Fish communities of interacting shallow-water habitats in tropical oceanic regions. Mar. Ecol. Prog. Ser. 58, 143–160 (1989).ADS 

    Google Scholar 
    McMahon, K. W., Berumen, M. L. & Thorrold, S. R. Linking habitat mosaics and connectivity in a coral reef seascape. Proc. Natl. Acad. Sci. USA 109, 15372–15376 (2012).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Carlson, R. R. et al. Synergistic benefits of conserving land-sea ecosystems. Glob. Ecol. Conserv. 28, e01684 (2021).Mwaluma, J. M. et al. Assemblage structure and distribution of fish larvae on the North Kenya Banks during the Southeast Monsoon season. Ocean Coast. Manag. 212, 105800 (2021).Joyeux, J. C. The abundance of fish larvae in estuaries: Within-tide variability at inlet and immigration. Estuaries 22, 889–904 (1999).
    Google Scholar 
    Able, K. W., Valenti, J. L. & Grothues, T. M. Fish larval supply to and within a lagoonal estuary: Multiple sources for Barnegat Bay New Jersey. Environ. Biol. Fish. 100, 663–683 (2017).
    Google Scholar 
    McClanahan, T. R. Seasonality in East Africa’s coastal waters. Mar. Ecol. Prog. Ser. 44, 191–199 (1988).ADS 

    Google Scholar 
    Aceves-Medina, G. et al. Distribution and abundance of the ichthyoplankton assemblages and its relationships with the geostrophic flow along the southern region of the California current. Lat. Am. J. Aquat. Res. 46, 104–119 (2018).
    Google Scholar 
    Gray, C. A. & Miskiewicz, A. G. Larval fish assemblages in south-east Australian coastal waters: Seasonal and spatial structure. Estuar. Coast. Shelf Sci. 50, 549–570 (2000).ADS 

    Google Scholar 
    Jiménez, M. P., Sánchez-Leal, R. F., González, C., García-Isarch, E. & García, A. Oceanographic scenario and fish larval distribution off Guinea-Bissau (north-west Africa). J. Mar. Biolog. Assoc. UK 95, 435–452.Mwaluma, J. M., Kaunda-Arara, B. & Rasowo, J. Diel and lunar variations in larval supply to Malindi Marine Park, Kenya. West Ind. Ocean J. Mar. Sci. 13, 57–67 (2014).
    Google Scholar 
    Stephens, J. S. Jr., Jordan, G. A., Morris, P. A., Singer, M. M. & McGowen, G. E. Can we relate larval fish abundance to recruitment or population stability? A preliminary analysis of recruitment to a temperate rocky reef. CalCOFI Rep. 27, 65–83 (1986).
    Google Scholar 
    Green, B. C., Smith, D. J., Grey, J. & Underwood, G. J. C. High site fidelity and low site connectivity in temperate salt marsh fish populations: A stable isotope approach. Oecologia 168, 245–255 (2012).ADS 
    PubMed 

    Google Scholar 
    Green, J. M. & Wroblewski, J. S. Movement patterns of Atlantic cod in Gilbert Bay, Labrador: Evidence for bay residency and spawning site fidelity. J. Mar. Biolog. Assoc. UK 80, 1077–1085 (2000).
    Google Scholar 
    Grüss, A., Kaplan, D. M. & Hart, D. R. Relative impacts of adult movement, larval dispersal and harvester movement on the effectiveness of reserve networks. PLoS ONE 6, e19960 (2011).Luiz, O. J. et al. Adult and larval traits as determinants of geographic range size among tropical reef fishes. Proc. Natl. Acad. Sci. USA 110, 16498–16502 (2013).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Macpherson, E. & Raventos, N. Relationship between pelagic larval duration and geographic distribution of Mediterranean littoral fishes. Mar. Ecol. Prog. Ser. 327, 257–265 (2006).ADS 

    Google Scholar 
    Green, A. L. et al. Larval dispersal and movement patterns of coral reef fishes, and implications for marine reserve network design. Biol. Rev. 90, 1215–1247 (2015).PubMed 

    Google Scholar 
    Taylor, M. D., Laffan, S. D., Fielder, D. S. & Suthers, I. M. Key habitat and home range of mulloway Argyrosomus japonicus in a south-east Australian estuary: Finding the estuarine niche to optimise stocking. Mar. Ecol. Prog. Ser. 328, 237–247 (2006).ADS 

    Google Scholar 
    Manson, F. J., Loneragan, N. R., Skilleter, G. A. & Phinn, S. R. An evaluation of the evidence for linkages between mangroves and fisheries: A synthesis of the literature and identification of research directions. Oceanogr. Mar. Biol. 43, 483–513 (2005).
    Google Scholar 
    Pattrick, P. & Strydom, N. A. Composition, abundance, distribution and seasonality of larval fishes in the shallow nearshore of the proposed Greater Addo Marine Reserve, Algoa Bay South Africa. Estuar. Coast. Shelf Sci. 79, 251–262 (2008).ADS 

    Google Scholar 
    Sato, N., Asahida, T., Terashima, H., Hurbungs, M. D. & Ida, H. Species composition and dynamics of larval and juvenile fishes in the surf zone of Mauritius. Environ. Biol. Fish. 81, 229–238 (2008).
    Google Scholar 
    Jaonalison, H., Mahafina, J. & Ponton, D. Fish post-larvae assemblages at two contrasted coral reef habitats in southwest Madagascar. Reg. Stud. Mar. Sci 6, 62–74 (2016).
    Google Scholar 
    Azmir, I. A., Esa, Y., Amin, S. M. N., Yasin, I. S. & Yusof, F. ZMd. Identification of larval fish in mangrove areas of Peninsular Malaysia using morphology and DNA barcoding methods. J. Appl. Ichthyol. 33, 998–1006 (2017).CAS 

    Google Scholar 
    Macedo-Soares, L. C. P., Freire, A. S. & Muelbert, J. H. Small-scale spatial and temporal variability of larval fish assemblages at an isolated oceanic island. Mar. Ecol. Prog. Ser. 444, 207–222 (2012).ADS 

    Google Scholar 
    Monteleone, D. M. Seasonality and abundance of ichthyoplankton in great South Bay, New York. Estuaries 15, 230–238 (1992).
    Google Scholar 
    Ara, R., Arshad, A., Amin, S. M. & Mazlan, A. G. Temporal and spatial distribution of fish larvae in different ecological habitats. Asian J. Anim. Vet. Adv. 8, 53–62 (2013).
    Google Scholar 
    Abu El-Regal, M. Abundance and diversity of coral reef fish larvae at Hurghada, Egyptian Red Sea. Egypt. J. Aquat. Biol. Fish. 12, 17–33 (2008).
    Google Scholar 
    Bialetzki, A., Nakatani, K., Sanches, P. V., Baumgartner, G. & Gomes, L. C. Larval fish assemblage in the Baía River (Mato Grosso do Sul State, Brazil): temporal and spatial patterns. Environ. Biol. Fish. 73, 37–47 (2005).
    Google Scholar 
    Dudley, B., Tolimieri, N. & Montgomery, J. Swimming ability of the larvae of some reef fishes from New Zealand waters. Mar. Freshw. Res. 51, 783–787. https://doi.org/10.1071/MF00062 (2000).Article 

    Google Scholar 
    Hare, J. A. et al. Biophysical mechanisms of larval fish ingress into Chesapeake Bay. Mar. Ecol. Prog. Ser. 303, 295–310 (2005).ADS 

    Google Scholar 
    Watt-pringle, P. & Strydom, N. A. Habitat use by larval fishes in a temperate South African surf zone. Estuar. Coast. Shelf Sci. 58, 765–774 (2003).ADS 

    Google Scholar 
    Picapedra, P. H. S., Sanches, P. V. & Lansac-Tôha, F. A. Effects of light-dark cycle on the spatial distribution and feeding activity of fish larvae of two co-occurring species (Pisces: Hypophthalmidae and Sciaenidae) in a neotropical floodplain lake. Braz. J. Biol. 78, 763–772 (2018).CAS 
    PubMed 

    Google Scholar 
    Cederlöf, U., Rydberg, L., Mgendi, M. & Mwaipopo, O. Tidal exchange in a warm tropical lagoon: Chwaka Bay, Zanzibar. Ambio 24, 458–464 (1995).
    Google Scholar 
    Gullström, M. et al. Assessment of changes in the seagrass-dominated submerged vegetation of tropical Chwaka Bay (Zanzibar) using satellite remote sensing. Estuar. Coast. Shelf Sci. 67, 399–408 (2006).ADS 

    Google Scholar 
    Gullström, M. et al. Seagrass meadows of Chwaka Bay: ecological, social and management aspects. In: de la Torre-Castro, M., Lyimo, T. J. (Eds) People, nature and research: past, present and future of Chwaka Bay, Zanzibar. ISBN: 978-9987-9559-1-6, Zanzibar Town: 89–109 (WIOMSA, 2012a)Gullström, M. et al. Connectivity and nursery function of shallow-water habitats in Chwaka Bay. In: de la Torre-Castro, M., Lyimo, T. J. (Eds) People, nature and research: past, present and future of Chwaka Bay, Zanzibar. ISBN: 978-9987-9559-1-6, Zanzibar Town: 175–192 (WIOMSA, 2012b)Rehren, J., Wolff, M. & Jiddawi, N. Holistic assessment of Chwaka Bay’s multi-gear fishery—using a trophic modeling approach. J. Mar. Syst. 180, 265–278 (2018).
    Google Scholar 
    Torell, E., Mmochi, A. & Palmigiano, K. Menai Bay Convernance Baseline. Coastal Resources Center, 1–18 (University of Rhode Island, 2006).Torell, E., Shalli, M., Francis, J., Kalangahe, B. & Munubi, R. Tanzania biodiversity threats assessment: Biodiversity threats and management opportunities for Fumba, Bagamoyo, and Mkuranga. 1–47 (University of Rhode Island, Narragansett, 2007).Jeyaseelan, M. J. P. Manual of fish eggs and larvae from Asian mangrove waters.193 (Paris: UNESCO Publishing, 1998).Mwaluma, J. M., Kaunda-Arara, B. & Strydom, N. A. A guide to commonly occurring larval stages of fishes in Kenyan Coastal Waters. WIOMSA Book Series No. 15. xvi + 73 (WIOMSA, 2014).Leis, J. M. & Carson-Ewart, B. M. (Eds.). The larvae of Indo-Pacific coastal fishes: an identification guide to marine fish larvae (Fauna Malesiana Handbooks 2), 804 (Brill, Leiden, 2000).Strickland, J. D. H. & Parsons, T. R. A practical handbook of seawater analysis, 2nd edn. Vol. 167. 21–26 (Bull. Fish. Res. Bd. Canada, 1972).Clarke, K. R. & Warwick, R. M. Change in Marine Communities: An Approach to Statistical Analysis and Interpretation (PRIMER-E). Plymouth Marine Laboratory, (Plymouth, UK, 2001). More

  • in

    Seasonal and temporal patterns of rainfall shape arthropod community composition and multi-trophic interactions in an arid environment

    Holmgren, M. et al. Extreme climatic events shape arid and semiarid ecosystems. Front. Ecol. Environ. 4, 87–95 (2006).
    Google Scholar 
    Ummenhofer, C. C. & Meehl, G. A. Extreme weather and climate events with ecological relevance: a review. Philos. Trans. R. Soc. B-Biol. Sci. 372, 20160135. https://doi.org/10.1098/rstb.2016.0135 (2017).Chesson, P. et al. Resource pulses, species interactions, and diversity maintenance in arid and semi-arid environments. Oecologia 141, 236–253 (2004).ADS 
    PubMed 

    Google Scholar 
    McCluney, K. E. et al. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change. Biol. Rev. 87, 563–582 (2012).PubMed 

    Google Scholar 
    Reyer, C. P. O. et al. A plant’s perspective of extremes: Terrestrial plant responses to changing climatic variability. Glob. Change Biol. 19, 75–89 (2013).ADS 

    Google Scholar 
    Scheffer, M., Carpenter, S., Foley, J. A., Folke, C. & Walker, B. Catastrophic shifts in ecosystems. Nature 413, 591–596 (2001).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Schwinning, S. & Sala, O. E. Hierarchy of responses to resource pulses in and and semi-arid ecosystems. Oecologia 141, 211–220 (2004).ADS 
    PubMed 

    Google Scholar 
    Borer, E. T., Seabloom, E. W. & Tilman, D. Plant diversity controls arthropod biomass and temporal stability. Ecol. Lett. 15, 1457–1464 (2012).PubMed 

    Google Scholar 
    Kwok, A. B. C., Wardle, G. M., Greenville, A. C. & Dickman, C. R. Long-term patterns of invertebrate abundance and relationships to environmental factors in arid Australia. Austral Ecol. 41, 480–491 (2016).
    Google Scholar 
    Prugh, L. R. et al. Ecological winners and losers of extreme drought in California. Nat. Climate Change 8, 819–824 (2018).ADS 

    Google Scholar 
    Deguines, N., Brashares, J. S. & Prugh, L. R. Precipitation alters interactions in a grassland ecological community. J. Anim. Ecol. 86, 262–272 (2017).PubMed 

    Google Scholar 
    Ripple, W. J. et al. What is a trophic cascade?. Trends Ecol. Evol. 31, 842–849 (2016).PubMed 

    Google Scholar 
    Greenville, A. C., Wardle, G. M. & Dickman, C. R. Extreme climatic events drive mammal irruptions: regression analysis of 100-year trends in desert rainfall and temperature. Ecol. Evol. 2, 2645–2658 (2012).PubMed 
    PubMed Central 

    Google Scholar 
    Molyneux, J., Pavey, C. R., James, A. I. & Carthew, S. M. Persistence of ground-dwelling invertebrates in desert grasslands during a period of low rainfall—Part 2. J. Arid. Environ. 157, 39–47 (2018).ADS 

    Google Scholar 
    Seymour, C. L., Simmons, R. E., Joseph, G. S. & Slingsby, J. A. On bird functional diversity: Species richness and functional differentiation show contrasting responses to rainfall and vegetation structure in an arid landscape. Ecosystems 18, 971–984 (2015).
    Google Scholar 
    Prather, C. M. et al. Invertebrates, ecosystem services and climate change. Biol. Rev. 88, 327–348 (2013).PubMed 

    Google Scholar 
    Del Toro, I., Ribbons, R. R. & Pelini, S. L. The little things that run the world revisited: a review of ant-mediated ecosystem services and disservices (Hymenoptera: Formicidae). Myrmecol. News 17, 133–146 (2012).
    Google Scholar 
    Gerlach, J., Samways, M. & Pryke, J. Terrestrial invertebrates as bioindicators: an overview of available taxonomic groups. J. Insect Conserv. 17, 831–850 (2013).
    Google Scholar 
    Doblas-Miranda, E., Sanchez-Pinero, F. & Gonzalez-Megias, A. Different microhabitats affect soil macroinvertebrate assemblages in a Mediterranean arid ecosystem. Appl. Soil Ecol. 41, 329–335 (2009).
    Google Scholar 
    Hadley, N. F. & Szarek, S. R. Productivity of desert ecosystems. Bioscience 31, 747–753 (1981).
    Google Scholar 
    Barnett, K. L. & Facey, S. L. Grasslands, invertebrates, and precipitation: A review of the effects of climate change. Front. Plant Sci. 7, 1196 (2016).PubMed 
    PubMed Central 

    Google Scholar 
    Zhu, H. et al. Effects of altered precipitation on insect community composition and structure in a meadow steppe. Ecol. Entomol. 39, 453–461 (2014).
    Google Scholar 
    Palmer, C. M. Chronological changes in terrestrial insect assemblages in the arid zone of Australia. Environ. Entomol. 39, 1775–1787 (2010).PubMed 

    Google Scholar 
    Liu, R. T., Zhu, F. & Steinberger, Y. Ground-active arthropod responses to rainfall-induced dune microhabitats in a desertified steppe ecosystem, China. J. Arid Land 8, 632–646 (2016).
    Google Scholar 
    Mendelsohn, J., Jarvis, A., Roberts, C. & Robertson, T. Atlas of Namibia: A portrait of the land and its people. 3rd edn, (Sunbird Publishers, 2009).Theron, L. Temporal and spatial composition of arboreal insects along the Omaruru river, Namibia Magister scientiae thesis, University of the Free State Bloemfontein, (2010).Wagner, T. C., Richter, J., Joubert, D. F. & Fischer, C. A dominance shift in arid savanna: An herbaceous legume outcompetes local C4 grasses. Ecol. Evol. 8, 6779–6787 (2018).PubMed 
    PubMed Central 

    Google Scholar 
    Wagner, T. C., Hane, S., Joubert, D. F. & Fischer, C. Herbaceous legume encroachment reduces grass productivity and density in arid rangelands. PLoS ONE 11, e0166743; https://doi.org/10.1371/journal.pone.0166743 (2016).Picker, M., Griffiths, C. & Weaving, A. Field Guide to Insects of Southern Africa. (Struik Nature, 2004).Scholtz, C. H. & Holm, E. Insects of Southern Africa. 2nd edn, (Protea Book House, 2008).Blaum, N., Seymour, C., Rossmanith, E., Schwager, M. & Jeltsch, F. Changes in arthropod diversity along a land use driven gradient of shrub cover in savanna rangelands: identification of suitable indicators. Biodivers. Conserv. 18, 1187–1199 (2009).
    Google Scholar 
    Franca, L. F., Figueiredo-Paixao, V. H., Duarte-Silva, T. A. & dos Santos, K. B. The effects of rainfall and arthropod abundance on breeding season of insectivorous birds, in a semi-arid neotropical environment. Zoologia-Curitiba. https://doi.org/10.3897/zoologia.37.e37716 (2020).Wagner, T. C., Uiseb, K. & Fischer, C. Rolling pits of Hartmann’s mountain zebra (Zebra equus hartmannae) increase vegetation diversity and landscape heterogeneity in the Pre-Namib. Ecol. Evol. 11, 13036–13051 (2021).PubMed 
    PubMed Central 

    Google Scholar 
    Dormann, C. F. et al. Collinearity: A review of methods to deal with it and a simulation study evaluating their performance. Ecography 36, 27–46 (2013).
    Google Scholar 
    R Core Team. R: A language and environment for statistical computing (R Foundation for Statistical Computing, Vienna, Austria, 2019).Oksanen, J., et al. vegan: Community Ecology Package. R package version 2.5-7. (2020).Legendre, P. & Gallagher, E. D. Ecologically meaningful transformations for ordination of species data. Oecologia 129, 271–280 (2001).ADS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Anderson, M. J. & Walsh, D. C. I. PERMANOVA, ANOSIM, and the Mantel test in the face of heterogeneous dispersions: What null hypothesis are you testing?. Ecol. Monogr. 83, 557–574 (2013).
    Google Scholar 
    Anderson, M. J. in Wiley StatsRef: Statistics Reference Online (eds N. Balakrishnan et al.) (2017).Stopher, K. V., Bento, A. I., Clutton-Brock, T. H., Pemberton, J. M. & Kruuk, L. E. B. Multiple pathways mediate the effects of climate change on maternal reproductive traits in a red deer population. Ecology 95, 3124–3138 (2014).
    Google Scholar 
    Bolker, B. M. et al. Generalized linear mixed models: A practical guide for ecology and evolution. Trends Ecol. Evol. 24, 127–135 (2009).PubMed 

    Google Scholar 
    Bates, D., Mächler, M., Bolker, B. & Walker, S. Fitting linear mixed-effects models using lme4. J. Stat. Softw. 67, 1–48 (2015).
    Google Scholar 
    Pinheiro, J. C. & Bates, D. M. Mixed-Effects Models in S and S-PLUS. (Springer Verlag, 2000).Zhang, D. rsq: R-Squared and related measures. R package version 2.2. (2021).Barnes, A. D. et al. Direct and cascading impacts of tropical land-use change on multi-trophic biodiversity. Nat. Ecol. Evol. 1, 1511–1519 (2017).PubMed 

    Google Scholar 
    Henschel, J. R. Long-term population dynamics of Namib desert Tenebrionid beetles reveal complex relationships to pulse-reserve conditions. Insects 12, 804. https://doi.org/10.3390/insects12090804 (2021).Cloudsley-Thompson, J. L. The adaptational diversity of desert biota. Environ. Conserv. 20, 227–231 (1993).
    Google Scholar 
    Sømme, L. in Invertebrates in Hot and Cold Arid Environments 135–157 (Springer, 1995).Suttle, K. B., Thomsen, M. A. & Power, M. E. Species interactions reverse grassland responses to changing climate. Science 315, 640–642 (2007).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Henschel, J., Klintenberg, P., Roberts, C. & Seely, M. Long-term ecological research from an arid, variable, drought-prone environment. Sécheresse 18, 342–347 (2007).
    Google Scholar 
    Cloudsley-Thompson, J. L. Adaptations of arthropoda to arid environments. Annu. Rev. Entomol. 20, 261–283 (1975).CAS 
    PubMed 

    Google Scholar 
    Schuldt, A. et al. Belowground top-down and aboveground bottom-up effects structure multitrophic community relationships in a biodiverse forest. Sci. Rep. 7 (2017).Vidal, M. C. & Murphy, S. M. Bottom-up vs. top-down effects on terrestrial insect herbivores: a meta-analysis. Ecol. Lett. 21, 138–150 (2018).Báez, S., Collins, S. L., Lightfoot, D. & Koontz, T. L. Bottom-up regulation of plant community structure in an aridland ecosystem. Ecology 87, 2746–2754 (2006).PubMed 

    Google Scholar 
    Gibb, H. et al. Testing top-down and bottom-up effects on arid zone beetle assemblages following mammal reintroduction. Austral Ecol. 43, 288–300 (2018).
    Google Scholar 
    Coll, M. & Guershon, M. Omnivory in terrestrial arthropods: Mixing plant and prey diets. Annu. Rev. Entomol. 47, 267–297 (2002).CAS 
    PubMed 

    Google Scholar 
    Karolyi, F., Hansal, T., Krenn, H. W. & Colville, J. F. Comparative morphology of the mouthparts of the megadiverse South African monkey beetles (Scarabaeidae: Hopliini): feeding adaptations and guild structure. PeerJ 4, e1597; https://doi.org/10.7717/peerj.1597 (2016).Greenslade, P. Survival of Collembola in arid environments: Observations in South Australia and the Sudan. J. Arid. Environ. 4, 219–228 (1981).ADS 

    Google Scholar 
    Fattorini, S. Effects of fire on tenebrionid communities of a Pinus pinea plantation: A case study in a Mediterranean site. Biodivers. Conserv. 19, 1237–1250 (2009).
    Google Scholar 
    Sanders, N. J., Moss, J. & Wagner, D. Patterns of ant species richness along elevational gradients in an arid ecosystem. Glob. Ecol. Biogeogr. 12, 93–102 (2003).
    Google Scholar  More

  • in

    Anti-pulling force and displacement deformation analysis of the anchor pulling system of the new debris flow grille dam

    Design parametersA new type of Debris-flow grille dam is proposed to be built with a height of 8 m. Column section 500 mm × 700 mm, spacing 5000 mm. The cross section of the beam is 400 mm × 300 mm, and the spacing is 4000 mm. The section steel adopts I-steel 45a, the spacing is 250 mm. The counterfort wall is 300 mm thick and 6500 mm high. Pile foundation adopts manual digging pile, pile by 1000 mm, 5000 mm deep. The concrete is C30; Stressed bar is HRB335; Stirrups is HRB300; Stay Cable is 3 (emptyset) s15.2. The design size of the anchor piers is shown in Fig. 12. In the Figure where (T = 2 times 10^{5} N); (L_{l} = 8500;{text{mm}}); (E_{l} = 1.95 times 10^{5} ;{text{N/mm}}^{2}); (A_{l} = 420;{text{mm}}); (D_{e} = 1000;{text{mm}}); (L_{m} = 1200;{text{mm}}); (E_{e} = 3.0 times 10^{4} ;{text{N/mm}}^{2}); (H = 1000;{text{mm}}); (mu = 0.2); (E = 20;{text{N/mm}}^{2}). The parameter of gully bed soil is shown in Table 1.Figure 12The parameters of anchor piers.Full size imageTable 1 The parameters of gully bed soil.Full size tableAnalysis of results(1) The effect of the elastic modulus and Poisson’s ratio of the surrounding soil on the displacement deformation of the anchor-pulling system.The elastic modulus (E) and Poisson’s ratio (mu) are important parameters for calculating the displacement deformation of soil. They have something to do with both the properties of materials and the stress level. To analyze the effect of the physical parameter variation of the surrounding soil on the displacement deformation of the anchor-pulling system, we can study changing the elastic modulus and Poisson’s ratio. The variation range of the elastic modulus is 15–45 N/mm2, and the variation range of Poisson’s ratio is 0.15–0.25.Figure 13 shows the variation curve in which the displacement deformation increases with the elastic modulus of the soil around the anchor pier. We can see that as the elastic modulus of the soil around the anchor pier increases, the displacement deformation decreases gradually. When the elastic modulus is in the range of 15–35 N/mm2, the curve is steep, and the decrease in deformation is apparent. After 35 N/mm2, the curve becomes smooth, and the decrease in deformation tends to be stable.Figure 13The effect of the elastic modulus E(15–45 N/mm2) of the surrounding soil on the displacement of the anchor-pulling system.Full size imageIn Fig. 14, the displacement deformation increases linearly with Poisson’s ratio of the soil around the anchor pier. However, the total impact is not large. From calculation, the variation of elastic modulus of the soil around the anchor pier has nothing to do with elastic deformation of the stayed cable ((S_{1} )), but mainly influences relative shear displacement between anchor piers and the surrounding soil ((S_{2} )) and the compression performance of the soil on the front of anchor piers ( (S_{3} )). where ((S_{2} )) accounted for 89% and (left( {S_{3} } right)) accounted for 11%. When the Poisson ratio increases, the displacement deformation also increases. Poisson’s ratio has the greatest influence on the relative shear displacement ((S_{2} )) of the anchor pier and soil, accounting for approximately 96.4%. The design parameters should be selected correctly during design. The influence of parameters on the deformation of anchor system is analyzed by using control variable method. The influence of a single variable on the results can be intuitively obtained. However, the elastic modulus E and Poisson ‘ s ratio (mu) of rock and soil are not independent. Therefore, Matlab is used to analyze the influence of the two aspects on the deformation of the tensile anchor system, and the results are shown in Fig. 15. It can be seen from Fig. 15 that the influence of elastic modulus E on the deformation of tensile anchor system is much greater than that of Poisson’s ratio (mu). And the variation of the curve is basically the same, so the interaction between the two is weak.Figure 14The effect of Poisson’s ratio (mu)(0.15–0.26) of the surrounding soil on the displacement of the anchor-pulling system.Full size imageFigure 15Influence of elastic modulus E (15–45 N/mm2) and Poisson’s ratio (mu left( {0.15 – 0.26} right)) on deformation of anchor system.Full size image(2) The effect of the design parameters of anchor piers on the displacement deformation of the anchor-pulling system.The design parameters of anchor piers include the equivalent width (D_{e}), length (L_{m}) and height (H). Different design parameters have varying effects on the displacement deformation of the anchor-pulling system. Keep other parameters unchanged and let ( D_{e} ) vary in 0.5–1.5 m, (L_{m}) vary in 0.6–2.0 m, and (H) vary in 0.5–1.5 m. Analyzing their effect on the displacement deformation of the anchor-pulling system, the results are shown in Figs. 16 and 17.Figure 16The effect of equivalent width (D_{e})(500–1500 mm) on the displacement of the anchor-pulling system.Full size imageFigure 17The effect of equivalent length (L_{m})(600–2000 mm) on the displacement of the anchor-pulling system.Full size imageAs illustrated in Figs. 16 and 17, the effects of the design parameters of the anchor piers on the displacement deformation of the anchor-pulling system are almost the same. As the size increases, the displacement deformation gradually decreases, and the front section decreases quickly, while the rear section becomes gradually smooth. Here, the equivalent width (D_{e}) and length (L_{m}) mainly affect the compression performance of the soil on the front of anchor piers (left( {S_{3} } right)). The anchor piers can be seen as rigid bodies where horizontal displacement takes place. Increasing the size means increasing the contact area between the anchor pier and soil body. With this increase, the compression performance of the soil on the front of the anchor piers decreases. However, the effect of the height (H) on the displacement deformation of the anchor-pulling system is the contribution to the relative shear displacement between the anchor piers and the surrounding soil ((S_{2} )). When (H) grows, ((S_{2} )) grows accordingly. However, theoretically, the larger the effect of the size, the better it is. Because of the constraint of topographic conditions, construction conditions and economic benefits in practical engineering, it is necessary to choose the best size. the anchor pier provides enough anchor force and saves all kinds of resources. The best design dimensions suggested are (D_{e}) = 1.2 m–1.8 m, (L_{m}) = 1.5 m–2.5 m, and (H) = 1.0 m–1.6 m.It can be seen from Fig. 18 that the width (D_{e}) and the height (L_{m}) of anchor pier influence each other greatly. When (D_{e}) is 600 mm, with the increase of (L_{m}), the deformation of tension anchor system will first decrease and then increase. When (D_{e}) is greater than 800 mm, with the increase of (L_{m}), the deformation of tension anchor system will continue to decrease. And with the increase of (L_{m}), the decreasing trend is more obvious. When (L_{m}) is 500 mm, with the increase of the height of the anchor pier (D_{e}), the deformation of the anchor system will increase first. When (L_{m}) is greater than 800 mm, with the increase of (D_{e}), the deformation of the anchor system will continue to decrease. But the decreasing trend is not much different.Figure 18Influence of Anchor Pier Width (D_{e} left( {500 – 1500;{text{mm}}} right)) and Anchor Pier Height (L_{m} left( {600 – 2000;{text{mm}}} right)) on Deformation of Anchorage System.Full size imageThe numerical validationThe establishment of the finite element modelWhen the finite element model of the anchor-pulling system and surrounding soil is created, the constitutive model of the surrounding soil uses the Mohr–Coulomb elastoplastic model. The anchor pier and surrounding soil use eight nodes as oparametric elements, such as solid45, of which the basic grid unit is cubic units. When the grid is divided, the grid between the anchor pier and the surrounding soil contact is dense. The LINK10 unit is used to simulate cables, which have a bilinear stiffness matrix. It can simulate not only tensile bar units but also compressed bar units. For example, when the pull-up option is used alone, if the unit is under pressure, its stiffness disappears, so it can be used to simulate the relaxation of cables or chains. This feature is very significant for the static problem of wire rope, which uses a unit to simulate the entire cable. It can also be used for dynamic analysis with inertial or damping effects when the needed relaxation unit should pay attention to its performance rather than its movement. The soil is homogeneous. The soil physical parameters and structure design parameters are consistent with the theoretical calculation parameters mentioned above. The tensile force of the cable is exerted on the nodes as a force. The top surface of the model is free, and the normal displacements of the remaining faces are constrained such that the displacements are zero. The contact of the anchor pier and surrounding soils is a rigid-flexible surface-to-surface contact element to reflect the interaction. The surface of the anchor pier is regarded as the “target” surface, and the surface of the soil body is regarded as the “contact” surface. The coefficient of friction and normal penalty stiffness are 0.35 and 0.15, respectively. The scope of interaction between the anchor pier and the surrounding soil in the model is taken as 15 m × 11 m × 12 m, referring to past experience in engineering and the research data of the effect scope that the related anchors have had on the soil. The values of the model geometric parameters and physical and mechanical parameters are the same as in “Design parameters” section. The finite element model is shown in Fig. 19.Figure 19Finite element model of the anchor-pulling system and surrounding soil.Full size imageResearch on finite element model gridIn order to verify the convergence of numerical simulation, the soil was divided into three different mesh sizes. Condition 1 is fine finite element meshing. The stress nephogram of condition 1 is shown in Fig. 20. Condition 2 is medium finite element mesh. The stress nephogram of condition 1 is shown in Fig. 21. Condition 3 is coarse finite element mesh. The stress nephogram of condition 1 is shown in Fig. 22. See Table 2 for specific grid division.Figure 20Condition 1 stress cloud diagram.Full size imageFigure 21Condition 1 stress cloud diagram.Full size imageFigure 22Condition 1 stress cloud diagram.Full size imageTable 2 Mesh size of three working conditions.Full size tableIt can be seen from the stress nephogram of the three working conditions that the thicker the grid is, the greater the displacement of the anchor system is. The maximum displacement difference between condition 2 and condition 3 is 2.6%; the maximum displacement of condition 1 is 17% different from that of condition 2. The finer the mesh, the more accurate the numerical simulation results. But with the increase in computing time. It can be seen from Table 2 that the maximum iteration of condition 1 is 10 times, and the result will converge. The maximum iterations of condition 2 and 3 only need 7 times, and the results can converge.The calculation resultsFigure 23 and Fig. 24 are the displacement nephograms of the soil around the anchor piers for 100 kN and 400 kN, respectively. The soil displacement increases with increasing load, the affected area will increase and become uniform, and the area under load will also increase. The soil within the range of 1–3 m around the anchor pier is greatly affected, accounting for 80% of the total force. The soil around the anchor pier should be reinforced, and the anchoring force should be enhanced in the design.Figure 23Displacement fringe of soil around the anchor piers for 100 kN.Full size imageFigure 24Displacement fringe of soil around the anchor piers for 400 kN.Full size imageIn order to further study the influence of anchorage pier size on the displacement and deformation of anchorage system, finite element models with different sizes are established by finite element method. The stress nephogram is shown in Figs. 25, 26 and 27.Figure 25Top 800 mm, bottom 800 mm anchor pier stress nephogram.Full size imageFigure 26Top 1000 mm, bottom 1000 mm anchor pier stress nephogram.Full size imageFigure 27Top 800 mm, bottom 1000 mm anchor pier stress nephogram.Full size imageFrom Figs. 25, 26 and 27, it can be seen that when the anchor pier is rectangular, the deformation of the tensile anchor system decreases with the increase of the size of the anchor pier, but the degree is small. When the anchor pier is trapezoidal, the material is small, but the deformation is more ideal than the rectangular. It can be seen that reasonable selection of anchor pier size is crucial, not blindly increase the size of anchor pier.Figure 28 shows that the displacement of the soil around the anchor pier increases with increasing load, and the added value is obvious at approximately 2–3 mm. Figure 29 shows that the increase in load has a great effect on the soil in front of the anchor pier. As the load increases, the compressive deformation of the soil gradually increases. As the distance from the anchor pier increases, the displacement of the soil decreases, and the scope of influence gradually decreases. The displacement of the soil tends to be stable beyond 4–5 m from the anchor pier.Figure 28The displacement of soil around anchor pier.Full size imageFigure 29The horizontal displacement of soil along cable axis.Full size imageComparison of theoretical calculation and numerical simulation results at the time of load variationTo verify the correctness of the theoretical calculation, we compare the theoretical calculation with numerical simulation results of displacement deformation of anchor-pulling system under different pulling force of stayed cable. The results are shown in Fig. 30, see Table 3 for data.Figure 30Comparison of theoretical calculation and numerical simulation results.Full size imageTable 3 Comparison between theoretical calculation and numerical simulation.Full size tableAs seen from Fig. 30, the theoretical and numerical simulation results are consistent, showing a linear growth trend. The slope difference of the two straight lines is approximately 5%, which meets the accuracy requirements of geotechnical engineering. As the restraint effect of the surrounding soil on the anchor pier is not fully considered, the theoretical calculation result is too large. The deformation of anchor (left( {S_{1} } right)) in displacement deformation is the same, and the relative shear displacement (left( {S_{2} } right)) of the anchor pier and the soil and the compressive deformation ((S_{3} )) of the soil at the front end of the anchor pier are 1.25 times and 1.08 times the numerical simulation results, respectively. The change in (left( {S_{2} } right)) in the calculation results is large and should be taken into account in the design. More

  • in

    Variation in diet composition and its relation to gut microbiota in a passerine bird

    Büyükdeveci, M. E., Balcázar, J. L., Demirkale, İ & Dikel, S. Effects of garlic-supplemented diet on growth performance and intestinal microbiota of rainbow trout (Oncorhynchus mykiss). Aquaculture 486, 170–174 (2018).
    Google Scholar 
    Maklakov, A. A. et al. Sex-specific fitness effects of nutrient intake on reproduction and lifespan. Curr. Biol. 18, 1062–1066 (2008).CAS 
    PubMed 

    Google Scholar 
    Totsch, S. K. et al. Effects of a Standard American Diet and an anti-inflammatory diet in male and female mice. Eur. J. Pain 22, 1203–1213 (2018).CAS 
    PubMed 

    Google Scholar 
    Green, D. A. & Millar, J. S. Changes in gut dimensions and capacity of Peromyscus maniculatus relative to diet quality and energy needs. Can. J. Zool. 65, 2159–2162 (1987).
    Google Scholar 
    Jones, V. A. et al. Crohn’s disease: Maintenance of remission by diet. Lancet 2, 177–180 (1985).CAS 
    PubMed 

    Google Scholar 
    Hirai, T. Ontogenetic change in the diet of the pond frog, Rana nigromaculata. Ecol. Res. 17, 639–644 (2002).
    Google Scholar 
    Qin, J. et al. A human gut microbial gene catalogue established by metagenomic sequencing. Nature 464, 59–65 (2010).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Sender, R., Fuchs, S. & Milo, R. Are we really vastly outnumbered? Revisiting the ratio of bacterial to host cells in humans. Cell 164, 337–340 (2016).CAS 
    PubMed 

    Google Scholar 
    Reikvam, D. H. et al. Depletion of murine intestinal microbiota: effects on gut mucosa and epithelial gene expression. PLoS ONE 6, e17996 (2011).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Sommer, F. & Bäckhed, F. The gut microbiota-masters of host development and physiology. Nat. Rev. Microbiol. 11, 227–238 (2013).CAS 
    PubMed 

    Google Scholar 
    Ley, R. E. et al. Evolution of mammals and their gut microbes. Science 320, 1647–1651 (2008).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Muegge, B. D. et al. Diet drives convergence in gut microbiome functions across mammalian phylogeny and within humans. Science 332, 970–974 (2011).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Youngblut, N. D. et al. Host diet and evolutionary history explain different aspects of gut microbiome diversity among vertebrate clades. Nat. Commun. 10, 2200 (2019).ADS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Ley, R. E., Turnbaugh, P. J., Klein, S. & Gordon, J. I. Microbial ecology: Human gut microbes associated with obesity. Nature 444, 1022–1023 (2006).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Zhu, Y. et al. Beef, chicken, and soy proteins in diets induce different gut microbiota and metabolites in rats. Front. Microbiol. 8, 1395 (2017).Zimmer, J. et al. A vegan or vegetarian diet substantially alters the human colonic faecal microbiota. Eur. J. Clin. Nutr. 66, 53–60 (2012).CAS 
    PubMed 

    Google Scholar 
    McKenney, E. A., Rodrigo, A. & Yoder, A. D. Patterns of gut bacterial colonization in three primate species. PLoS ONE 10, e0124618 (2015).PubMed 
    PubMed Central 

    Google Scholar 
    Bergmann, G. T. Microbial community composition along the digestive tract in forage- and grain-fed bison. BMC Vet. Res. 13, 253 (2017).PubMed 
    PubMed Central 

    Google Scholar 
    Phillips, C. D. et al. Microbiome structural and functional interactions across host dietary niche space. Integr. Comp. Biol. 57, 743–755 (2017).CAS 
    PubMed 

    Google Scholar 
    Song, S. J. et al. Comparative analyses of vertebrate gut microbiomes reveal convergence between birds and bats. mBio 11, e02901–19 (2020).Bodawatta, K. H., Sam, K., Jønsson, K. A. & Poulsen, M. Comparative analyses of the digestive tract microbiota of New Guinean passerine birds. Front. Microbiol. 9, 1830 (2018).Capunitan, D. C., Johnson, O., Terrill, R. S. & Hird, S. M. Evolutionary signal in the gut microbiomes of 74 bird species from Equatorial Guinea. Mol. Ecol. 29, 829–847 (2020).CAS 
    PubMed 

    Google Scholar 
    Hird, S. M., Sánchez, C., Carstens, B. C. & Brumfield, R. T. Comparative gut microbiota of 59 neotropical bird species. Front. Microbiol. 6, 1403 (2015).PubMed 
    PubMed Central 

    Google Scholar 
    Waite, D. W. & Taylor, M. W. Characterizing the avian gut microbiota: membership, driving influences, and potential function. Front. Microbiol 5, 223 (2014).PubMed 
    PubMed Central 

    Google Scholar 
    Loo, W. T., Dudaniec, R. Y., Kleindorfer, S. & Cavanaugh, C. M. An inter-island comparison of Darwin’s finches reveals the impact of habitat, host phylogeny, and island on the gut microbiome. PLoS ONE 14, e0226432 (2019).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Loo, W. T., García-Loor, J., Dudaniec, R. Y., Kleindorfer, S. & Cavanaugh, C. M. Host phylogeny, diet, and habitat differentiate the gut microbiomes of Darwin’s finches on Santa Cruz Island. Sci. Rep. 9, 1–12 (2019).
    Google Scholar 
    Murray, M. H. et al. Gut microbiome shifts with urbanization and potentially facilitates a zoonotic pathogen in a wading bird. PLoS ONE 15, e0220926 (2020).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Orłowski, G. & Karg, J. Diet of nestling Barn Swallows Hirundo rustica in rural areas of Poland. Cent. Eur. J. Biol. 6, 1023–1035 (2011).
    Google Scholar 
    Wiesenborn, W. D. & Heydon, S. L. Diets of breeding southwestern willow flycatchers in different habitats. Wilson J. Ornithol. 119, 547–557 (2007).
    Google Scholar 
    Moreby, S. J. An aid to the identification of arthropod fragments in the faeces of gamebird chicks (Galliformes). Ibis 130, 519–526 (1988).
    Google Scholar 
    Zeale, M. R. K., Butlin, R. K., Barker, G. L. A., Lees, D. C. & Jones, G. Taxon-specific PCR for DNA barcoding arthropod prey in bat faeces. Mol. Ecol. Resour. 11, 236–244 (2011).CAS 
    PubMed 

    Google Scholar 
    Bolnick, D. I. et al. Individuals’ diet diversity influences gut microbial diversity in two freshwater fish (threespine stickleback and Eurasian perch). Ecol. Lett. 17, 979–987 (2014).PubMed 
    PubMed Central 

    Google Scholar 
    Bolnick, D. I. et al. Individual diet has sex-dependent effects on vertebrate gut microbiota. Nat. Commun. 5, 4500 (2014).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Clarke, L. J., Soubrier, J., Weyrich, L. S. & Cooper, A. Environmental metabarcodes for insects: In silico PCR reveals potential for taxonomic bias. Mol. Ecol. Resour. 14, 1160–1170 (2014).CAS 
    PubMed 

    Google Scholar 
    Deagle, B. E., Jarman, S. N., Coissac, E., Pompanon, F. & Taberlet, P. DNA metabarcoding and the cytochrome c oxidase subunit I marker: Not a perfect match. Biol. Lett. 10, 20140562 (2014).Elbrecht, V. et al. Testing the potential of a ribosomal 16S marker for DNA metabarcoding of insects. PeerJ 4, e1966 (2016).PubMed 
    PubMed Central 

    Google Scholar 
    Elbrecht, V. & Leese, F. Can DNA-based ecosystem assessments quantify species abundance? Testing primer bias and biomass—Sequence relationships with an innovative metabarcoding protocol. PLoS ONE 10, e0130324 (2015).PubMed 
    PubMed Central 

    Google Scholar 
    Piñol, J., San Andrés, V., Clare, E. L., Mir, G. & Symondson, W. O. C. A pragmatic approach to the analysis of diets of generalist predators: The use of next-generation sequencing with no blocking probes. Mol. Ecol. Resour. 14, 18–26 (2014).PubMed 

    Google Scholar 
    Góngora, E., Elliott, K. H. & Whyte, L. Gut microbiome is affected by inter-sexual and inter-seasonal variation in diet for thick-billed murres (Uria lomvia). Sci. Rep. 11, 1200 (2021).PubMed 
    PubMed Central 

    Google Scholar 
    Teyssier, A. et al. Diet contributes to urban-induced alterations in gut microbiota: Experimental evidence from a wild passerine. Proc. R. Soc. B 287, 20192182 (2020).PubMed 
    PubMed Central 

    Google Scholar 
    Kreisinger, J. et al. Temporal stability and the effect of transgenerational transfer on fecal microbiota structure in a long distance migratory bird. Front. Microbiol. 8, 50 (2017).PubMed 
    PubMed Central 

    Google Scholar 
    Petrželková, A. et al. Brood parasitism and quasi-parasitism in the European barn swallow (Hirundo rustica rustica). Behav. Ecol. Sociobiol. 69, 1405–1414 (2015).
    Google Scholar 
    Kreisinger, J. et al. Fecal microbiota associated with phytohaemagglutinin-induced immune response in nestlings of a passerine bird. Ecol. Evol. 8, 9793–9802 (2018).PubMed 
    PubMed Central 

    Google Scholar 
    Klindworth, A. et al. Evaluation of general 16S ribosomal RNA gene PCR primers for classical and next-generation sequencing-based diversity studies. Nucleic Acids Res. 41, e1 (2013).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Elbrecht, V. & Leese, F. Validation and development of COI metabarcoding primers for freshwater macroinvertebrate bioassessment. Front. Environ. Sci. 5, 11 (2017).Jiang, H., Lei, R., Ding, S.-W. & Zhu, S. Skewer: a fast and accurate adapter trimmer for next-generation sequencing paired-end reads. BMC Bioinform. 15, 182 (2014).
    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/ (2018).Callahan, B. J. et al. DADA2: High-resolution sample inference from Illumina amplicon data. Nat Meth 13, 581–583 (2016).CAS 

    Google Scholar 
    Pafčo, B. et al. Metabarcoding analysis of strongylid nematode diversity in two sympatric primate species. Sci. Rep. 8, 5933 (2018).ADS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Wang, Q., Garrity, G. M., Tiedje, J. M. & Cole, J. R. Naive Bayesian classifier for rapid assignment of rRNA sequences into the new bacterial taxonomy. Appl. Environ. Microbiol. 73, 5261–5267 (2007).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    McMurdie, P. J. & Holmes, S. phyloseq: An R package for reproducible interactive analysis and graphics of microbiome census data. PLoS ONE 8, e61217 (2013).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Edgar, R. C., Haas, B. J., Clemente, J. C., Quince, C. & Knight, R. UCHIME improves sensitivity and speed of chimera detection. Bioinformatics 27, 2194–2200 (2011).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Quast, C. et al. The SILVA ribosomal RNA gene database project: Improved data processing and web-based tools. Nucleic Acids Res. 41, D590–D596 (2013).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Wright, E. S. RNAconTest: Comparing tools for noncoding RNA multiple sequence alignment based on structural consistency. RNA 26, 531–540 (2020).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Price, M. N., Dehal, P. S. & Arkin, A. P. FastTree: Computing large minimum evolution trees with profiles instead of a distance matrix. Mol. Biol. Evol. 26, 1641–1650 (2009).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Douglas, G. M. et al. PICRUSt2 for prediction of metagenome functions. Nat. Biotechnol. 38, 685–688 (2020).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Caspi, R. et al. The MetaCyc database of metabolic pathways and enzymes—A 2019 update. Nucleic Acids Res. 48, D445–D453 (2020).CAS 
    PubMed 

    Google Scholar 
    Ondov, B. D., Bergman, N. H. & Phillippy, A. M. Interactive metagenomic visualization in a Web browser. BMC Bioinform. 12, 385 (2011).
    Google Scholar 
    Stoffel, M. A., Nakagawa, S. & Schielzeth, H. rptR: Repeatability estimation and variance decomposition by generalized linear mixed-effects models. Methods Ecol. Evol. 8, 1639–1644 (2017).
    Google Scholar 
    Schielzeth, H. Simple means to improve the interpretability of regression coefficients. Methods Ecol. Evol. 1, 103–113 (2010).
    Google Scholar 
    Legendre, P. & Anderson, M. J. Distance-based redundancy analysis: Testing multispecies responses in multifactorial ecological experiments. Ecol. Monogr. 69, 1–24 (1999).
    Google Scholar 
    Oksanen, J. et al. vegan: Community Ecology Package. R package version 2.5-2. 2018. (2018).Love, M. I., Huber, W. & Anders, S. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biol. 15, 550 (2014).Benjamini, Y. & Hochberg, Y. Controlling the false discovery rate: A practical and powerful approach to multiple testing. J. R. Stat. Soc. Ser. B (Methodol.) 57, 289–300 (1995).MathSciNet 
    MATH 

    Google Scholar 
    Hui, F. K. C. boral–Bayesian ordination and regression analysis of multivariate abundance data in R. Methods Ecol. Evol. 7, 744–750 (2016).
    Google Scholar 
    Aivelo, T. & Norberg, A. Parasite-microbiota interactions potentially affect intestinal communities in wild mammals. J. Anim. Ecol. 87, 438–447 (2018).PubMed 

    Google Scholar 
    Caviedes-Vidal, E. et al. The digestive adaptation of flying vertebrates: High intestinal paracellular absorption compensates for smaller guts. Proc. Natl. Acad. Sci. U.S.A. 104, 19132–19137 (2007).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    McWhorter, T. J., Caviedes-Vidal, E. & Karasov, W. H. The integration of digestion and osmoregulation in the avian gut. Biol. Rev. Camb. Philos. Soc. 84, 533–565 (2009).PubMed 

    Google Scholar 
    Grigolo, C. P. et al. Diet heterogeneity and antioxidant defence in Barn Swallow Hirundo rustica nestlings. Avocetta 43, 1 (2019).
    Google Scholar 
    Law, A. A. et al. Diet and prey selection of barn swallows (Hirundo rustica) at Vancouver International Airport. Canadian Field-Naturalist 131, 26 (2017).
    Google Scholar 
    McClenaghan, B., Nol, E. & Kerr, K. C. R. DNA metabarcoding reveals the broad and flexible diet of a declining aerial insectivore. Auk 136, uky003 (2019).Turner, A. K. The use of time and energy by aerial feeding birds (University of Stirling, 1981).
    Google Scholar 
    Bryant, D. M. & Turner, A. K. Central place foraging by swallows (Hirundinidae): The question of load size. Anim. Behav. 30, 845–856 (1982).
    Google Scholar 
    Møller, A. P. Advantages and disadvantages of coloniality in the swallow, Hirundo rustica. Anim. Behav. 35, 819–832 (1987).
    Google Scholar 
    Brodmann, P. A. & Reyer, H.-U. Nestling provisioning in water pipits (Anthus spinoletta): Do parents go for specific nutrients or profitable prey?. Oecologia 120, 506–514 (1999).ADS 
    PubMed 

    Google Scholar 
    Herlugson, C. J. Food of adult and nestling Western and Mountain bluebirds. Murrelet 63, 59–65 (1982).
    Google Scholar 
    Batt, B. D. J., Anderson, M. G. & Afton, A. D. Ecology and management of breeding waterfowl (Univ of Minnesota Press, 1992).
    Google Scholar 
    Douglas, D. J. T., Evans, D. M. & Redpath, S. M. Selection of foraging habitat and nestling diet by Meadow Pipits Anthus pratensis breeding on intensively grazed moorland. Bird Study 55, 290–296 (2008).
    Google Scholar 
    Waugh, D. R. Predation strategies in aerial feeding birds (University of Stirling, 1978).
    Google Scholar 
    Kropáčková, L. et al. Co-diversification of gastrointestinal microbiota and phylogeny in passerines is not explained by ecological divergence. Mol. Ecol. 26, 5292–5304 (2017).PubMed 

    Google Scholar 
    Kohl, K. D. et al. Physiological and microbial adjustments to diet quality permit facultative herbivory in an omnivorous lizard. J. Exp. Biol. 219, 1903–1912 (2016).PubMed 

    Google Scholar 
    Baxter, N. T. et al. Intra- and interindividual variations mask interspecies variation in the microbiota of sympatric Peromyscus populations. Appl. Environ. Microbiol. 81, 396–404 (2015).ADS 
    PubMed 

    Google Scholar 
    Holmes, I. A., Monagan, I. V. Jr., Rabosky, D. L. & Davis Rabosky, A. R. Metabolically similar cohorts of bacteria exhibit strong cooccurrence patterns with diet items and eukaryotic microbes in lizard guts. Ecol. Evol. 9, 12471–12481 (2019).PubMed 
    PubMed Central 

    Google Scholar 
    Li, H. et al. Diet diversity is associated with beta but not alpha diversity of pika gut microbiota. Front. Microbiol. 7, 1169 (2016).Li, H. et al. Diet simplification selects for high gut microbial diversity and strong fermenting ability in high-altitude pikas. Appl. Microbiol. Biotechnol. 102, 6739–6751 (2018).CAS 
    PubMed 

    Google Scholar 
    Ambrosini, R. et al. Cloacal microbiomes and ecology of individual barn swallows. FEMS Microbiol. Ecol. 95, fiz061 (2019).Kreisinger, J., Čížková, D., Kropáčková, L. & Albrecht, T. Cloacal microbiome structure in a long-distance migratory bird assessed using deep 16sRNA pyrosequencing. PLoS ONE 10, e0137401 (2015).PubMed 
    PubMed Central 

    Google Scholar 
    Noguera, J. C., Aira, M., Pérez-Losada, M., Domínguez, J. & Velando, A. Glucocorticoids modulate gastrointestinal microbiome in a wild bird. R. Soc. Open Sci. 5, 171743 (2018).Shehzad, W. et al. Carnivore diet analysis based on next-generation sequencing: Application to the leopard cat (Prionailurus bengalensis) in Pakistan. Mol. Ecol. 21, 1951–1965 (2012).CAS 
    PubMed 

    Google Scholar 
    Vestheim, H. & Jarman, S. N. Blocking primers to enhance PCR amplification of rare sequences in mixed samples—A case study on prey DNA in Antarctic krill stomachs. Front. Zool. 5, 12 (2008).PubMed 
    PubMed Central 

    Google Scholar  More

  • in

    Infection strategy and biogeography distinguish cosmopolitan groups of marine jumbo bacteriophages

    Detection and validation of high-quality jumbo phage binsDue to the large size of jumbo bacteriophage genomes, it is likely that they are present in multiple distinct contigs in metagenomic datasets and therefore require binning to recover high-quality metagenome-assembled genomes (MAGs) [28]. This has been shown for large DNA viruses that infect eukaryotes, where several recent studies have successfully employed binning approaches to recover viral MAGs [2, 3, 30]. Here, we used the same 1545 high-quality metagenomic assemblies [31] used in a recent study to recover giant viruses of eukaryotes [3], but we modified the bioinformatic pipeline to identify bins of jumbo bacteriophages. These metagenomes were compiled by Parks et al. [31] and included available metagenomes on the NCBI’s Short Read Archive by December 31, 2015 (see Parks et al. [31]). This dataset includes a wide variety of marine metagenomes (n = 469) including many non-Tara metagenomes (n = 165). We focused our benchmarking and distribution analyses on Tara data [29] because of the well-curated metadata and size fractions in this dataset. We first binned the contigs from these assemblies with MetaBat2 [32], which groups contigs together based on similar nucleotide composition and coverage profiles, and focused on bins of at least 200 kilobases in total length. We subsequently identified bins composed of bacteriophage contigs through analysis with VirSorter2 [33], VIBRANT [34], and CheckV [35] (see Methods for details).The occurrence of multiple copies of highly conserved marker genes is typically used to assess the level of contamination present in metagenome-derived genomes of bacteria and archaea [36]. Because bacteriophage lack these marker genes [37], we developed alternative strategies to assess possible contamination in our jumbo phage bins. Firstly, we refined the set of bins by retaining those with no more than 5 contigs that were each at least 5 kilobases in length to reduce the possibility that spurious contigs were put together. Secondly, we assessed the possibility that two strains of smaller phages with similar nucleotide composition may be binned together by aligning the contigs in a bin to each other. Bins that had contigs with high sequence similarity across the majority of their lengths were discarded (Supplementary Fig. 1). Thirdly, we discarded bins if their contigs exhibited aberrant co-abundance profiles in different metagenomes (see Supplementary Methods). To generate these co-abundance profiles, we mapped reads from 225 marine metagenomes provided by Tara Oceans [29] onto the bins. Coverage variation between contigs was benchmarked based on read-mapping results from artificially-fragmented reference genomes present in the samples (See Methods for details). Only bins with coverage variation below our empirically-derived threshold were retained. Using this stringent filtering, we identified 85 bins belonging to jumbo bacteriophages. These bins ranged in length from 202 kbp to 498 kbp, and 31 consisted of a single contig, while 54 consisted of 2–5 contigs (Supplementary Fig. 2).To assess global diversity patterns of jumbo bacteriophages, we combined these jumbo phage bins together with a compiled database of previously-identified jumbo phages that included all complete jumbo Caudovirales genomes on RefSeq (downloaded July 5th, 2020), the INPHARED database [14], a recent survey of cultivated jumbo phages [6], the Al-Shayeb et al. study [4], and marine jumbo phage contigs from metagenomic surveys of GOV 2.0 [26] (60 jumbo phages), ALOHA 2.0 [38] (8 jumbo phages), and one megaphage MAG recovered from datasets of the English Channel [39]. Ultimately, we arrived at a set of 244 jumbo phages, including the 85 bins, that were present in at least one Tara Oceans sample (min. 20% genome covered, see Methods) or deriving from a marine dataset (i.e. ALOHA, GOV 2.0) which we analyzed further in this study and refer to as marine jumbo phages. Statistics on genomic features can be found in Supplementary Dataset 1.Marine jumbo phages belong to distinct groups with diverse infection strategiesBecause bacteriophages lack high-resolution, universal marker genes for classification, such as 16S rRNA in bacteria, phages are often grouped by gene content [40, 41]. Here, we generated a bipartite network that included the 85 bins of jumbo phages with a dataset of available Caudovirales complete genomes in RefSeq (3012 genomes; downloaded July 5th, 2020) and the full set of reference jumbo phages described above. To construct the bipartite network, we compared proteins encoded in all the phage genomes to the VOG database, and each genome was linked to VOG hits that were present (Fig. 1, Supplementary Dataset 2, see Methods for details). To identify groups of phage genomes with similar VOG profiles, we employed a spinglass community detection algorithm [42] to generate genome clusters. Similar methods have recently been used to analyze evolutionary relationships in other dsDNA viruses [41]. The marine jumbo phages of this study clustered into five groups that included both jumbo and non-jumbo phage genomes (Fig. 2a). We refer to these five clusters as Phage Genome Clusters (PGCs): PGC_A, PGC_B, PGC_C, PGC_D, and PGC_E. These PGCs included cultured phages and metagenome-derived jumbo phages found in various environments (i.e. aquatic, engineered) and isolated on a diversity of hosts (i.e. Firmicutes, Proteobacteria, Bacteroidetes) (Fig. 2b, c). Of the marine jumbo phages, 135 belonged to PGC_A, 11 to PGC_B, 90 to PGC_C, 7 to PGC_D, and 1 to PGC_E (Fig. 1b). In addition to this network-based analysis, we also examined phylogenies of the major capsid protein (MCP) and the terminase large subunit (TerL) encoded by the marine jumbo phages and the same reference phage set examined in the network (Fig. 1c, d). With the exception of PGC_A, the marine jumbo phages that belong to the same PGC appeared more closely related to each other than those belonging to different clusters. The polyphyletic placement of jumbo phage PGCs in these marker gene phylogenies is consistent with the view that genome gigantism evolved multiple times, independently within the Caudovirales [6].Fig. 1: Bipartite network and marker gene analyses of jumbo phages.a Network with marine jumbos and references as nodes and edges based on shared VOGs. Marine jumbo phage nodes are colored by PGC as detected with spinglass community detection analysis, other nodes are in gray. Edges and VOG nodes have been omitted to more clearly represent the pattern of phage clustering. Node size corresponds to the natural log of genome length in kilobases. b Barchart of the number of members in each PGC. PGCs with marine jumbo phages are denoted with a star and the number of marine jumbo phages in that PGC. Proportion of marine jumbo phages in that PGC is colored. Phylogenies of TerL (c) and MCP (d) proteins with references and bins. Inner ring and branches are colored by the 5 PGCs that marine jumbo phages belong to. Navy blue circles in the outer ring denote marine jumbo phages.Full size imageFig. 2: Statistics of the Phage Genomes Clusters (PGCs).a Boxplot of genome length in each network cluster (x-axis is PGC number). Star denotes PGC with a marine jumbo phage and the color matches the PGC letters of Fig. 1. b Stacked barplot of the metagenome environment from which each phage derives from in each PGC (x-axis). Reference (yellow) are cultured phages, in black are the bins of jumbo phages from this study. c Stacked barplot of the host phylum of the RefSeq cultured phages in each cluster; metagenomic phages are in gray.Full size imageWe then compared functional content encoded by the marine jumbo phages in the PGCs to identify functional differences that distinguish these groups. PGC_E was excluded from this analysis because this genome cluster contained only a single jumbo phage. Collectively, most genes of the marine jumbo phages could not be assigned a function (mean: 86.60%, std dev: 7.01%; Supplementary Dataset 3), which is common with environmental viruses [43, 44]. Genes with known functions primarily belonged to functional categories related to viral replication machinery, such as information processing and virion structure (Fig. 3a), and these genes drove the variation between the genome clusters of marine jumbo phages (Fig. 3b). A recent comparative genomic analysis of cultivated jumbo phages was able to identify three types of jumbo phages that are defined by different infection strategies and host interactions (referred to as Groups 1–3) [6]. We cross-referenced our PGCs and found that PGCs B, C, and D of this study corresponded to Groups 1, 2, and 3, respectively, suggesting that these genome clusters contain phages with distinct infection and replication strategies. PGC_A corresponded to multiple groups, indicating that this genome cluster contains a particularly broad diversity of phages.Fig. 3: Functional predictions of PGCs.a Functional categories for genes encoded by jumbo phages averaged by PGC. b Heatmap of proportion of genomes in each PGC that contain the listed genes. Listed genes were selected based on containing a known function and having a variance between the PGCs above 0.2. Dendrogram was generated based on hierarchical clustering in pheatmap.Full size imageThe second largest phage cluster with marine jumbo phages, PGC_B, consists of 238 phages (11 (4.6%) marine jumbo phages, including 10 bins generated here), and included cultured phages of Group 1, which is typified by Pseudomonas aeruginosa phage PhiKZ. Supporting this correspondence with Group 1, all marine jumbo phages of PGC_B encoded the same distinct replication and transcription machinery, including a divergent family B DNA polymerase and a multi-subunit RNA polymerase (Fig. 3b, Supplementary Dataset 3). These marine jumbo phages also encoded a PhiKZ internal head protein, and they uniquely encoded shell and tubulin homologs which has recently been found in PhiKZ phages to assist in the formation of a nucleus-like compartment during infection that protects the replicating phage from host defenses [18, 19]. Although we could not confidently predict hosts for the 11 metagenomic marine jumbo phages in this PGC_B (Supplementary Dataset 1), the cultured phages of this genome cluster infect pathogenic bacteria belonging to the phyla Proteobacteria (178 phages) and Firmicutes (6 phages) (Fig. 2c), implicating a potential host range for marine jumbo phages in PGC_B.The next largest phage genome cluster, PGC_C, comprised of 156 phages total (90 marine jumbo phages (57.7%); 4 bins generated from this study) and included reference jumbo phages in Group 2 (31, 19.9%) which are typified by Alphaproteobacteria and Cyanobacteria phages. Likewise, the host range of other cultured phages in PGC_C support the Group 2 correspondence, either infecting Cyanobacteria (139 phages) or Proteobacteria (4 phages) (Fig. 2c). Furthermore, all 3 marine metagenomic phages in PGC_C for which hosts could be predicted were matched to Cyanobacteria hosts (Supplementary Dataset 1). Functional annotations of PGC_C marine jumbo phages revealed nearly all encode a family B DNA polymerase (97.8% of phages) and the photosystem II D2 protein (PF00124, VOG04549) characteristic of cyanophages (90% of phages) (Fig. 3b). This PGC included the reference Prochlorococcus phage P-TIM68 (NC_028955.1), which encodes components of both photosystem I and II as a mechanism to enhance cyclic electron flow during infection [45]. This suggests that an enhanced complement of genes used to manipulate host physiology during infection may be a driver of large genome sizes in this group. Additionally, most of the PGC_C marine jumbo phages encoded lipopolysaccharide biosynthesis proteins (76%), which have been found in cyanophage genomes that may induce a “pseudolysogeny” state, when infected host cells are dormant, by changing the surface of the host cell and preventing additional phage infections [6] (Supplementary Dataset 3). Taken together, most marine jumbo phages of PGC_C likely follow host interactions of jumbo cyanophages, such as potentially manipulating host metabolism by encoding their own photosynthetic genes and potentially inducing a pseudolysogenic state.Finally, phages of PGC_D totaled at 47 phages, of which 7 were marine jumbo phages generated in this study (14.9%). This group included Group 3 jumbo phages (15, 31.9%), which is primarily distinguished by encoding a T7-type DNA polymerase but is not typified by a particular phage type or host range. Supporting this grouping, all marine jumbo phages in this study encoded a T7 DNA polymerase which belongs to family A DNA polymerases (Fig. 3b, Supplementary Dataset 3). Most of the other genes distinctively encoded by the marine jumbo phages in this group included structural genes related to T7 (T7 baseplate, T7 capsid proteins), a eukaryotic DNA topoisomerase I catalytic core (PF01028), and DNA structural modification genes (MmcB-like DNA repair protein, DNA gyrase B). Hosts of metagenomic marine jumbo phages in PGC_D could not be predicted (Supplementary Dataset 1); however, cultured Group 3 jumbo phages in PGC_D all infect Proteobacteria, primarily Enterobacteria and other pathogens.The largest of the phage genome clusters, PGC_A, contained 469 phages, including 135 marine jumbo phages (63 bins from this study). This genome cluster contained the largest jumbo phages, such as Bacillus phage G (498 kb) and the marine megaphage Mar_Mega_1 (656 kb) recently recovered from the English Channel [39]. Unlike other PGCs, PGC_A contained mostly metagenomic phages (401, 85%, Fig. 2b, c). Considering PGC_A contains the largest jumbo phages (Figs. 1b, 2a), the vast genetic diversity in this PGC might explain why few genes were found to distinguish this group. Of the genes unique to PGC_A, only one was present in at least half of the phages (51.9%), which was a Bacterial DNA polymerase III alpha NTPase domain (PF07733). The host ranges of cultured phages from this PGC further reflect the large diversity of this group and included a variety of phyla and genera that can perform complex metabolisms or lifestyles, such as the nitrogen-fixing Cyanobacteria of the Nodularia genus isolated from the Baltic Sea (accessions NC_048756.1 and NC_048757.1) and the Bacteroidetes bacteria Rhodothermus isolated from a hot spring in Iceland (NC_004735.1) [46]. Because this group contains an abundance of metagenome-derived genomes that encode mostly proteins with no VOG annotation (Supplementary Dataset 2), it is possible that it includes several distinct lineages that could not be distinguished using the community detection algorithm of the bipartite network analysis.Relative abundance of jumbo bacteriophages across size fractionsTo explore the distribution of the marine jumbo phages in the ocean, we first examined the size fractions in which the jumbo phages were most prevalent. To remove redundancy for the purposes of read mapping, we examined the 244 jumbo phages at the population-level ( >80% genes shared with >95% average nucleotide identity [24]), corresponding to 142 populations (11 unique to this study, corresponding to 47 bins). We then mapped Tara Oceans metagenomes onto the 142 jumbo phage populations, and 102 of these populations could be detected [min. 20% of genome covered], resulting in 74 populations in PGC_A, 2 in PGC_B, 22 in PGC_C, 3 in PGC_D, and 1 in PGC_E. Out of the 225 Tara Oceans metagenomes examined, 213 (94.6%) contained at least one jumbo phage population (median: 7, Supplementary Dataset 4). Jumbo phages were more frequently detected in samples below 0.22 µm ( More

  • in

    Functional representativeness and distinctiveness of reintroduced birds and mammals in Europe

    Cardinale, B. J., Palmer, M. A. & Collins, S. L. Species diversity enhances ecosystem functioning through interspecific facilitation. Nature 415, 426–429 (2002).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Gagic, V. et al. Functional identity and diversity of animals predict ecosystem functioning better than species-based indices. Proc. R. Soc. Lond. B Biol. Sci. 282, 20142620 (2015).
    Google Scholar 
    Oliver, T. H. et al. Biodiversity and resilience of ecosystem functions. Trends Ecol. Evol. 30, 673–684 (2015).PubMed 

    Google Scholar 
    Oliver, T. H. et al. Declining resilience of ecosystem functions under biodiversity loss. Nat. Commun. 6, 10122 (2015).ADS 
    PubMed 

    Google Scholar 
    Wardle, D. A. Do experiments exploring plant diversity–ecosystem functioning relationships inform how biodiversity loss impacts natural ecosystems?. J. Veg. Sci. 27, 646–653 (2016).
    Google Scholar 
    Cadotte, M. W., Carscadden, K. & Mirotchnick, N. Beyond species: Functional diversity and the maintenance of ecological processes and services. J. Appl. Ecol. 48, 1079–1087 (2011).
    Google Scholar 
    Petchey, O. L. & Gaston, K. J. Extinction and the loss of functional diversity. Proc. R. Soc. Lond. B Biol. Sci. 269, 1721–1727 (2002).
    Google Scholar 
    Rosenfeld, J. S. Functional redundancy in ecology and conservation. Oikos 98, 156–162 (2002).
    Google Scholar 
    Fonseca, C. R. & Ganade, G. Species functional redundancy, random extinctions and the stability of ecosystems. J. Ecol. 89, 118–125 (2001).
    Google Scholar 
    Mouillot, D. et al. Functional over-redundancy and high functional vulnerability in global fish faunas on tropical reefs. PNAS 111, 13757–13762 (2014).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Violle, C. et al. Let the concept of trait be functional!. Oikos 116, 882–892 (2007).
    Google Scholar 
    Laughlin, D. C. Applying trait-based models to achieve functional targets for theory-driven ecological restoration. Ecol. Lett. 17, 771–784 (2014).PubMed 

    Google Scholar 
    Laughlin, D. C., Strahan, R. T., Huffman, D. W. & Sánchez Meador, A. J. Using trait-based ecology to restore resilient ecosystems: Historical conditions and the future of montane forests in western North America. Restor. Ecol. 25, S135–S146 (2017).
    Google Scholar 
    Petchey, O. L. & Gaston, K. J. Functional diversity (FD), species richness and community composition. Ecol. Lett. 5, 402–411 (2002).
    Google Scholar 
    Carmona, C. P., de Bello, F., Mason, N. W. H. & Lepš, J. Traits without borders: Integrating functional diversity across scales. Trends Ecol. Evol. 31, 382–394 (2016).PubMed 

    Google Scholar 
    Jain, M. et al. The importance of rare species: A trait-based assessment of rare species contributions to functional diversity and possible ecosystem function in tall-grass prairies. Ecol. Evol. 4(104), 112 (2014).
    Google Scholar 
    Mouillot, D. et al. Rare species support vulnerable functions in high-diversity ecosystems. PLoS Biol. 11, e1001569 (2013).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Leitão, R. P. et al. Rare species contribute disproportionately to the functional structure of species assemblages. Proc. R. Soc. B 283, 20160084 (2016).PubMed 
    PubMed Central 

    Google Scholar 
    IUCN/SSC. Guidelines for Reintroductions and Other Conservation Translocations. (IUCN Species Survival Commission, 2013).Bakker, E. S. & Svenning, J.-C. Trophic rewilding: Impact on ecosystems under global change. Philos. Trans. R. Soc. B Biol. Sci. 373, 20170432 (2018).
    Google Scholar 
    Garrido, P. et al. Experimental rewilding enhances grassland functional composition and pollinator habitat use. J. Appl. Ecol. 56, 946–955 (2019).
    Google Scholar 
    Svenning, J.-C. et al. Science for a wilder Anthropocene: Synthesis and future directions for trophic rewilding research. Proc. Natl. Acad. Sci. 113, 898–906 (2016).ADS 
    CAS 
    PubMed 

    Google Scholar 
    Estes, J. A. et al. Trophic downgrading of planet earth. Science 333, 301–306 (2011).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Ritchie, E. G. et al. Ecosystem restoration with teeth: What role for predators?. Trends Ecol. Evol. 27, 265–271 (2012).PubMed 

    Google Scholar 
    Chauvenet, A. L. M., Canessa, S. & Ewen, J. G. Setting objectives and defining the success of reintroductions. In Reintroduction of Fish and Wildlife Populations 105–121 (University of California Press, 2016).Ewen, J. G., Soorae, P. S. & Canessa, S. Reintroduction objectives, decisions and outcomes: Global perspectives from the herpetofauna. Anim. Conserv. 17, 74–81 (2014).
    Google Scholar 
    Kleiman, D. G., Price, M. R. S. & Beck, B. B. Criteria for reintroductions. In Creative Conservation: Interactive Management of Wild and Captive Animals (eds. Olney, P. J. S., Mace, G. M. & Feistner, A. T. C.) 287–303 (Springer Netherlands, 1994). https://doi.org/10.1007/978-94-011-0721-1_14.Hunter, M. L. & Hutchinson, A. The virtues and shortcomings of parochialism: Conserving species that are locally rare, but globally common. Conserv. Biol. 8, 1163–1165 (1994).
    Google Scholar 
    Brichieri-Colombi, T. A. & Moehrenschlager, A. Alignment of threat, effort, and perceived success in North American conservation translocations. Conserv. Biol. 30, 1159–1172 (2016).PubMed 

    Google Scholar 
    Thévenin, C., Mouchet, M., Robert, A., Kerbiriou, C. & Sarrazin, F. Reintroductions of birds and mammals involve evolutionarily distinct species at the regional scale. PNAS https://doi.org/10.1073/pnas.1714599115 (2018).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    Seddon, P. J., Soorae, P. S. & Launay, F. Taxonomic bias in reintroduction projects. Anim. Conserv. 8, 51–58 (2005).
    Google Scholar 
    Thévenin, C., Morin, A., Kerbiriou, C., Sarrazin, F. & Robert, A. Heterogeneity in the allocation of reintroduction efforts among terrestrial mammals in Europe. Biol. Conserv. 241, 108346 (2020).
    Google Scholar 
    Devictor, V. et al. Spatial mismatch and congruence between taxonomic, phylogenetic and functional diversity: The need for integrative conservation strategies in a changing world. Ecol. Lett. 13, 1030–1040 (2010).PubMed 

    Google Scholar 
    Crees, J. J., Turvey, S. T., Freeman, R. & Carbone, C. Mammalian tolerance to humans is predicted by body mass: Evidence from long-term archives. Ecology 100, e02783 (2019).PubMed 

    Google Scholar 
    Sandom, C., Faurby, S., Sandel, B. & Svenning, J.-C. Global late Quaternary megafauna extinctions linked to humans, not climate change. Proc. R. Soc. B Biol. Sci. 281, 20133254 (2014).
    Google Scholar 
    Wilman, H. et al. EltonTraits 1.0: Species-level foraging attributes of the world’s birds and mammals. Ecology 95, 2027–2027 (2014).
    Google Scholar 
    Dı́az, S. & Cabido, M. Vive la différence: Plant functional diversity matters to ecosystem processes. Trends Ecol. Evol. 16, 646–655 (2001).
    Google Scholar 
    Mlambo, M. C. Not all traits are ‘functional’: Insights from taxonomy and biodiversity-ecosystem functioning research. Biodivers. Conserv. 23, 781–790 (2014).
    Google Scholar 
    van der Plas, F. et al. Plant traits alone are poor predictors of ecosystem properties and long-term ecosystem functioning. Nat. Ecol. Evol. 4, 1602–1611 (2020).PubMed 

    Google Scholar 
    Lavorel, S. & Garnier, E. Predicting changes in community composition and ecosystem functioning from plant traits: Revisiting the Holy Grail. Funct. Ecol. 16, 545–556 (2002).
    Google Scholar 
    Luck, G. W., Lavorel, S., McIntyre, S. & Lumb, K. Improving the application of vertebrate trait-based frameworks to the study of ecosystem services. J. Anim. Ecol. 81, 1065–1076 (2012).PubMed 

    Google Scholar 
    Mouchet, M. et al. Towards a consensus for calculating dendrogram-based functional diversity indices. Oikos 117, 794–800 (2008).
    Google Scholar 
    Podani, J. & Schmera, D. On dendrogram-based measures of functional diversity. Oikos 115, 179–185 (2006).
    Google Scholar 
    Maire, E., Grenouillet, G., Brosse, S. & Villéger, S. How many dimensions are needed to accurately assess functional diversity? A pragmatic approach for assessing the quality of functional spaces. Glob. Ecol. Biogeogr. 24, 728–740 (2015).
    Google Scholar 
    Villéger, S., Maire, E. & Leprieur, F. On the risks of using dendrograms to measure functional diversity and multidimensional spaces to measure phylogenetic diversity: A comment on Sobral et al. (2016). Ecol. Lett. 20, 554–557 (2017).PubMed 

    Google Scholar 
    Tsirogiannis, C. & Sandel, B. PhyloMeasures: A package for computing phylogenetic biodiversity measures and their statistical moments. Ecography 39, 709–714 (2016).
    Google Scholar 
    Isaac, N. J., Turvey, S. T., Collen, B., Waterman, C. & Baillie, J. E. Mammals on the EDGE: Conservation priorities based on threat and phylogeny. PLoS ONE 2, e296 (2007).ADS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Paradis, E., Claude, J. & Strimmer, K. APE: Analyses of phylogenetics and evolution in R language. Bioinformatics 20, 289–290 (2004).CAS 

    Google Scholar 
    Hidasi-Neto, J., Loyola, R. & Cianciaruso, M. V. Global and local evolutionary and ecological distinctiveness of terrestrial mammals: Identifying priorities across scales. Divers. Distrib. 21, 548–559 (2015).
    Google Scholar 
    Dovrat, G., Meron, E., Shachak, M., Golodets, C. & Osem, Y. The relative contributions of functional diversity and functional identity to ecosystem function in water-limited environments. J. Veg. Sci. 30, 427–437 (2019).
    Google Scholar 
    Funk, J. L. et al. Revisiting the Holy Grail: Using plant functional traits to understand ecological processes. Biol. Rev. 92, 1156–1173 (2017).PubMed 

    Google Scholar 
    Kuebbing, S. E. & Bradford, M. A. The potential for mass ratio and trait divergence effects to explain idiosyncratic impacts of non-native invasive plants on carbon mineralization of decomposing leaf litter. Funct. Ecol. 33, 1156–1171 (2019).
    Google Scholar 
    Devictor, V. et al. Defining and measuring ecological specialization. J. Appl. Ecol. 47, 15–25 (2010).
    Google Scholar 
    Byers, J. E. et al. Using ecosystem engineers to restore ecological systems. Trends Ecol. Evol. 21, 493–500 (2006).PubMed 

    Google Scholar 
    Jones, C. G., Lawton, J. H. & Shachak, M. Organisms as ecosystem engineers. In Ecosystem Management: Selected Readings (eds. Samson, F. B. & Knopf, F. L.) 130–147 (Springer, 1996). https://doi.org/10.1007/978-1-4612-4018-1_14.Macdonald, D. W. et al. Reintroducing the beaver (Castor fiber) to Scotland: A protocol for identifying and assessing suitable release sites. Anim. Conserv. 3, 125–133 (2000).
    Google Scholar 
    Wilmers, C. C., Crabtree, R. L., Smith, D. W., Murphy, K. M. & Getz, W. M. Trophic facilitation by introduced top predators: Grey wolf subsidies to scavengers in Yellowstone National Park. J. Anim. Ecol. 72, 909–916 (2003).
    Google Scholar 
    Dupont, H., Mihoub, J.-B., Bobbé, S. & Sarrazin, F. Modelling carcass disposal practices: Implications for the management of an ecological service provided by vultures. J. Appl. Ecol. 49, 404–411 (2012).
    Google Scholar 
    Moleon, M. et al. Humans and scavengers: The evolution of interactions and ecosystem services. Bioscience 64, 394–403 (2014).
    Google Scholar 
    Legras, G., Loiseau, N., Gaertner, J.-C., Poggiale, J.-C. & Gaertner-Mazouni, N. Assessing functional diversity: The influence of the number of the functional traits. Theor. Ecol. 13, 117–126 (2020).
    Google Scholar 
    Petchey, O. L. & Gaston, K. J. Functional diversity: Back to basics and looking forward. Ecol. Lett. 9, 741–758 (2006).PubMed 

    Google Scholar 
    Díaz, S. et al. The global spectrum of plant form and function. Nature 529, 167–171 (2016).ADS 
    PubMed 

    Google Scholar 
    Lundgren, E. J. et al. Introduced herbivores restore Late Pleistocene ecological functions. Proc. Natl. Acad. Sci. 117, 7871–7878 (2020).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Malhi, Y. et al. Megafauna and ecosystem function from the Pleistocene to the Anthropocene. PNAS 113, 838–846 (2016).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Osborne, P. E. & Seddon, P. J. Selecting suitable habitats for reintroductions: Variation, change and the role of species distribution modelling. Reintrod. Biol. Integr. Sci. Manag. 1, 73–104 (2012).
    Google Scholar 
    Lipsey, M. K., Child, M. F., Seddon, P. J., Armstrong, D. P. & Maloney, R. F. Combining the fields of reintroduction biology and restoration ecology. Conserv. Biol. 21, 1387–1390 (2007).PubMed 

    Google Scholar 
    Perino, A. et al. Rewilding complex ecosystems. Science 364, eaav5570 (2019).CAS 
    PubMed 

    Google Scholar 
    Loiseau, N. et al. Global distribution and conservation status of ecologically rare mammal and bird species. Nat. Commun. 11, 5071 (2020).ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Cadotte, M. W. & Tucker, C. M. Difficult decisions: Strategies for conservation prioritization when taxonomic, phylogenetic and functional diversity are not spatially congruent. Biol. Conserv. 225, 128–133 (2018).
    Google Scholar 
    Sarrazin, F. & Barbault, R. Reintroduction: Challenges and lessons for basic ecology. Trends Ecol. Evol. (Amst.) 11, 474–478 (1996).CAS 

    Google Scholar  More

  • in

    Spinal fracture reveals an accident episode in Eremotherium laurillardi shedding light on the formation of a fossil assemblage

    Since the bone discontinuities noted in the three vertebrae analyzed show no clear sign of bone overgrowth, it is pivotal to rule out the possibility that we are dealing with preservation damages before proposing an accurate diagnosis for the lesions. The close-up view examination of the abnormalities shows that their edges have clear signs of smoothing and rounding (Fig. 1), which represent important evidence of osteoblastic activity18,19. Additionally, the similar color of the cortical damage and normal bone can be used as secondary evidence to rule out post-mortem processes as a possible origin of the alterations, since recent destructive processes are lighter than the rest of the bone19. Therefore, as taphonomic processes can be ruled out, the pointed evidence strongly suggests that the discontinuities observed are of pathological origin. More specifically, these breaks found in all three vertebrae are indicative of bone fracture.Based on fracture analysis criteria applied here20, which consider the location and morphological pattern of the fractures, we classified the fractures noted in all vertebrae as traumas belonging to Type A (vertebral body compression), Group A2 (split fractures), and subgroup A2.1 (sagittal split fracture). This diagnosis implies that the traumatic episode was likely caused by a compressive force on the vertebral column, which split the vertebral bodies in the sagittal plane. This type of injury is considered stable—i.e., the fracture does not have a tendency to displace after reduction—and neurological deficit is uncommon20,22,23. Although stable traumas cause only moderate pain, without generating significant movement limitations20, the Eremotherium individual here analyzed died with unhealed bones, as there is no evidence of callus formation.The absence of other skeletal signs that point to the presence of another type of disease concomitantly to the fractures allows us to reject the possibility that they have been generated as a result of a pre-existing disease (e.g., infection, neoplasm). We also consider that the vertebral injuries were not caused by repetitive force (stress fractures) because this type of injury is commonly characterized as a nondisplaced line or crack in the bone, called hairline fracture3. Those refer to situations where the broken bone fragments are not visibly out of alignment and exhibit very little relative displacement21. Although the Eremotherium vertebrae fractures’ can be described as nondisplaced, they also have a noticeable gap between their edges that is mostly narrow with wider parts in the middle, something found in split fractures20 but that is not characteristic of hairline fractures. Lastly, the subgroup C1.2.1 (rotational sagittal split fracture) might be a source of confusion due to similar morphological pattern with subgroup A2.1 (sagittal split fracture). However, in subgroup C1.2.1 there are compressive and rotational forces acting simultaneously, producing total separation into two parts20, which clearly did not occur in the vertebrae analyzed here.In humans, compression fractures are most commonly caused by osteoporosis, although infection, neoplasm and trauma can also be etiological factors23,24,25. However, as aforementioned, the absence of other pathological skeletal marks is an important characteristic to take note as it serves to disregard the possibility of the fractures’ genesis to be secondary to another pathology. As such, in this case, osteoporosis, infection and neoplasm are unlikely etiologies. On the other hand, a compression fracture in a healthy individual is commonly generated after a severe traumatic event such as a fall from great height23,26. This scenario seems to better explain the origin of the vertebral fractures in the case of the Eremotherium ground sloth herein studied.The three fractured vertebrae were recovered in the Toca das Onças site (Fig. 2), a small cave considered as one of the richest paleontological sites of the Brazilian Quaternary15. Two complete skeletons of Eremotherium laurillardi and fragments belonging to at least thirteen other individuals, together with several other bones assigned to different smaller species are known to this cave14. It comprises of a single dry chamber that can only be entered through vertical entrances approximately 4.5 m high (Figs. 2b–d and 3). Two different hypotheses concerning the depositional process of Toca da Onças were previously proposed: (1) the animals climbed down into the cave in search of water14; or (2) due to the vertical character of the cave entrance, it could have functioned as a natural trap where animals accidentally fell into the cave15.Figure 2Location map of the Toca das Onças site and images of the cave. (a) Detail of the location, (b) cave entrance area view, (c) view from inside the cave, (d) Cave entrance detail. Scale bars 10 m in (b) and 5 m in (c). This figure was generated by Adobe Photoshop CS6 software (https://www.adobe.com/br/products/photoshop.html).Full size imageFigure 3Schematic representation of the Toca das Onças site. (a) Ground plan of the cave illustrating its morphology and dimension, (b) Cross-section illustrating the abyss-shaped entrance.Full size imageThe first hypothesis would indicate that the animal fell into the cave during an attempt to climb down. However, there is no report in the literature indicating that Eremotherium laurillardi could have been a climbing animal. In addition, the vertical morphology of the cave entrance would be a limiting factor for climbing behavior (see Fig. 3).Therefore, based on the type of fracture (compression sagittal split fracture) observed in the three vertebrae of Eremotherium as well as the inferred origin mechanism (fall from a great height), the presence of the individual here analyzed in the fossil accumulation of Toca das Onças is more likely explained by the second hypothesis. This idea is not particularly new as ‘entrapment due to fall’ has been described as a fossil accumulation mode to several other caves worldwide (e.g.,27,28). However, the use of bones fractures as an indicator of fossil accumulation mode is an interesting novelty. Of course, a detailed taphonomic investigation in the Toca das Onças still needs to be conducted in order to accurately interpret the formation of this important Quaternary fossil accumulation from Brazil.In sum, we suggest that the animal accidentally fell into the cave, fractured at least three sequential vertebrae (12th, 13th thoracic vertebrae and 1st lumbar vertebra) after the impact on the ground, survived for a while, but succumbed trapped inside the cave without food and water (Fig. 4). Other animals found in the cave, but without signs of bone fracture, may have fallen and not fractured their bones or not survived after the fall, especially the smaller ones. Finally, the proposal of falls to explain the unusual record of giant ground sloth fossils preserving much of its skeleton in caves, as reported for Toca das Onças site, contrasts with the better-documented pattern of skeletal accumulation via hydraulic action.Figure 4Artistic reconstruction of the suggested fall of the individual Eremotherium laurillardi into the cave. Artwork by Júlia d’Oliveira.Full size image More

  • in

    Spatio-temporal analysis identifies marine mammal stranding hotspots along the Indian coastline

    Our compiled dataset consisted of 1674 records of marine mammal records after removing duplicate reports. It included 660 reports of sightings, 59 reports of induced mortalities or hunting records, 240 reports of incidental mortalities, 632 unique stranding records (live / dead), and 83 records which could not be categorised because of incomplete information.SightingsA total of 660 opportunistic sightings (number of individuals, ni = 3299) were recorded throughout the Indian coastline between 1748 and 2017 (Fig. 1a, 2a, 3a). Sighting data on the east coast (species = 18, ni = 1105) was mostly restricted to Odisha and Tamil Nadu (representing 97% of total east coast sightings). On the west coast (ni = 1297), Maharashtra (ni = 549), Gujarat (ni = 248) and Karnataka (ni = 307) contributed to highest sighting records (representing 85% of total west coast sightings). Sightings from the islands also contributed to 24.85% of the dataset (Andaman & Nicobar Islands = 24.37%, Lakshadweep = 0.48%). Highest incidence of sightings was for DFP (ni = 1894) followed by dugongs (ni = 959), BW (ni = 58) and SBW (ni = 17).Figure 1Marine mammal records obtained from data compiled between years 1748 – 2017 along the east coast, west coast and the islands of India for the groups i.e., baleen whales (BW), dolphins and finless porpoise (DFP), sperm and beaked whales (SBW) and dugongs, given as color-coded stacked bars where (a) sighting records—records where live animals were sighted (b) induced mortalities—records where animals were reported hunted or killed or were driven ashore, (c) incidental mortalities—records where animals were found dead after entanglement in fishing nets or being struck by vessels and (d) stranding records—records where dead or live animals were found washed ashore, or floating near shore or stranded alive and were attempted for rescue.Full size imageFigure 2Marine mammal records obtained every year from the data compiled between years 1748–2017 along Indian coastline given as cumulative numbers for each group i.e., baleen whales (BW), dolphins and finless porpoise (DFP), sperm and beaked whales (SBW) and dugongs, as color-coded stacked bars, where (a) sighting records—records where live animals were sighted (b) induced mortalities—records where animals were reported hunted or killed or were driven ashore, (c) incidental mortalities—records where animals were found dead after entanglement in fishing nets or being struck by vessels and (d) stranding records—records where dead or live animals were found washed ashore, or floating near shore or stranded alive and were attempted for rescue.Full size imageFigure 3Bubble plots showing distribution of marine mammal records obtained from data compiled between years 1748–2017 along the Indian coastline for each group i.e., baleen whales (BW), dolphins and finless porpoise (DFP), sperm and beaked whales (SBW) and dugongs, as color-coded stacked bars, where (a) sighting—records where live animals were sighted (b) induced mortalities—records where animals were reported hunted or killed or were driven ashore, (c) incidental mortalities—records where animals were found dead after entanglement in fishing nets or being struck by vessels and (d) strandings—records where dead or live animals were found washed ashore, or floating near shore or stranded alive and were attempted for rescue. Size of the bubble indicates number of individuals. These maps were created using ArcGIS 10.5 (https://desktop.arcgis.com/en/arcmap/10.3/map/working-with-layers/about-symbolizing-layers-to-represent-quantity.htm).Full size imageInduced mortalitiesA total of 59 incidences (ni = 102) were recorded of marine mammals being hunted/ captured between the years 1748–2017 (Fig. 1b, 2b, 3b). The total number of animals hunted/ captured deliberately is similar along east coast (ni = 33), west coast (ni = 29) and islands (ni = 36). Out of all marine mammal species, 90% of the animals hunted at the east coast were dugong D. dugon (ni = 30, all from Tamil Nadu). On the west coast, records of hunting incidences of finless porpoise Neophocaena phocaenoides were highest (79% of total records on west coast, Goa ni = 17, Kerala ni = 4, Karnataka and Maharashtra ni = 1). In the islands (i.e., Andaman and Nicobar Islands), 94% of the hunting records were of dugongs (ni = 34).Incidental mortalitiesA total of 240 net entanglements (ni = 1356) were reported along the Indian coast between the years 1748 and 2017 (Fig. 1c, 2c, 3c). Similar counts of individuals entangled along east (ni = 670) and west coast (ni = 654) were obtained with low reporting from the islands (ni = 26). Fourteen species were reported entangled from both east and west coast with only 4 species recorded from the islands. D. dugon was found to be most frequently entangled along the east coast (63 incidences, ni = 594, contributing to 56% of the total numbers on east coast), followed by Tursiops sp. (11 incidences, ni = 14, 9% of the east coast dataset). On the west coast, Tursiops sp. was the most frequently entangled (18 incidences, ni = 117, contributing to 18% of the west coast dataset), followed by N. phocaenoides (17 incidences, ni = 34, contributing to 17% of the dataset). The total number of DFP being entangled from west coast (ni = 623) were higher than east coast (ni = 68). More dugong individuals were entangled along east coast (i.e., from Tamil Nadu; ni = 594) as compared to the west coast (i.e., Gujarat; ni = 3) and Islands (i.e., Andaman and Nicobar; ni = 19). D. dugon was the most frequently entangled species in the islands (19 incidences, ni = 19, contributing to 79% of the total numbers in islands dataset) followed by false killer whale Pseudorca crassidens (3 incidences, ni = 5, contributing to 12% of the islands dataset). Very few BW or SBW (11 incidences, ni = 11) were recorded accidently entangled throughout the Indian coastline.StrandingsMarine mammals stranding reports consisted of 91.93% dead (ni = 581) and 8.07% live strandings (ni = 51) (Figs. 1d, 2d, 3d). Considering mass strandings as strandings with ni  > 2 (excluding mother and calf;33,34), 8.5% of all reports were mass strandings (21 strandings, ni = 1054). Most of the records did not have information about the sex of the stranded animal (83%), the age class (88%) or the state of decomposition of the carcass (53%). Highest strandings were reported of dugongs (strandings = 190, ni = 228), followed by BW (strandings = 178, ni =  = 190), DFP (strandings = 157, ni =  = 552) and SBW (strandings = 47, individuals = 48). There were 54 incidences (ni = 54, 9% of total stranding data) where the animal was not identified reliably to include in either of the groups.Species composition and frequencies of strandings were different on east coast, west coast and in the islands (Fig. 1, Table 1). Twenty-two species were reported as stranded on the east coast with D. dugon as the most frequently stranded species (83 incidences, ni = 107, ~ 29% of all records), followed by Indo-Pacific humpback dolphin Sousa chinensis, (31 incidences, ni = 108, ~ 10% of all records). On the west coast, out of 20 species reported as stranded, Balaenoptera musculus was most frequent (28 incidences, ni = 29, ~ 12% of all records) followed by N. phocaenoides (23 incidences, ni = 39, ~ 10% of all records). In the islands, 13 species were reported as stranded, D. dugon (93 incidences, ni = 102, contributing to 77% of the total animals found on the islands) followed by strandings of sperm whale Physeter macrocephalus (8 incidences, ni = 8, contributing to 6% of the data; Table 1).

    a. Baleen whales

    Table 1 Number of stranding events reported for marine mammals between 1748–2017 in India from the east coast, the west coast and Lakshadweep and Andaman & Nicobar archipelagos.Full size tableA total of 178 BW strandings (ni = 190) were reported. Most species were unidentified (east coast ni= 27, west coast ni = 58, islands ni = 4; i.e., 47% of the data). Identified strandings comprised of 6 species (see Table 1), some of which were later found to be misidentification (no confirmed evidence for common Minke Whale Balaenoptera acutorostrata, Sei Whale Balaenoptera borealis and Fin Whale Balaenoptera physalus from Indian waters; MMRCNI, 2018). Higher number of strandings occurred on the west coast (ni = 126), as compared to east coast (ni = 60). The east and west coast reported all six species of BW, whereas only three species stranded on the islands. B. borealis (misidentified) was the most stranded species across the east coast (12 incidences, ni = 12, contributing to 11% of the data) whereas blue whale Balaenoptera musculus was the most frequent across the west coast (28 incidences, ni = 29, contributing to 11% of the data). Baleen whale strandings were rare in the islands (4 incidences, ni = 4).Forty-seven SBW strandings (ni = 48) were reported along the Indian coast. More SBW stranded on the east coast (ni = 23) as compared to the west coast (ni = 13) and the islands (ni = 12). P. macrocephalus was most frequently reported (70% of all SBW records, east coast ni = 20, west coast ni = 6, islands ni = 8).There were 157 strandings (ni =552) of DFP belonging to 14 species. Twenty-one of these events were mass strandings (ni  > 2). The largest mass stranding event (ni = 147) occurred of short-finned pilot whale Globicephala macrorhynchus along the west coast (Tamil Nadu). Higher number of DFP strandings were recorded from east coast (ni = 418) as compared to west coast (ni = 83) and the islands (ni = 51; Table 1). East coast received a higher diversity of stranded DFP (number of species = 11) as compared to west coasts (number of species = 9) and the islands (number of species = 3). S. chinensis was the most frequently stranded species along the east coast (31 incidences, ni = 108, contributing to 33% of the data) whereas N. phocaenoides was the most frequent along the west coast (23 incidences, ni = 39, contributing to 37% of the data; Table 1).

    d. Dugongs

    The current distribution of dugongs in India is in the shallow coastal waters of Gujarat, Tamil Nadu and Andaman & Nicobar Islands37,38. There are 190 stranding events recorded between the years 1893 and 2017. The highest number of stranded dugongs were recorded from Tamil Nadu (ni = 107) closely followed by Andaman and Nicobar Islands (ni = 102) and few records from Gujarat (ni = 19).Temporal stranding patternsOur analysis of temporal trends for the last 42 years (1975–2017) showed that the mean number of strandings along the Indian coast was 11.25 ± SE 1.39 / year. The number of stranding reports show an increasing trend for two decades after 1975, dropping between 1995 and 2004. We observed a distinct rise in strandings post 2005 (18.23 ± SE 2.98 / year) with the highest reports from 2015–17 (27.66 ± SE 8.51/year) (Fig. 4).

    a. Baleen whales

    Figure 4A beanplot of decadal trends in marine mammal stranding in India from data compiled between years 1975–2017. Data prior to 1975 was discontinuous over the years to be considered for decadal trends. The data for last decade considered here includes only two years (2015–17) where increased reporting is evident. The bold horizontal lines indicate the mean number of strandings in each decade whereas the smaller horizontal lines indicate stranding numbers recorded for each year within the decade.Full size imageOn the west coast, mean stranding rate throughout the years (1975–2017) was 0.0010 ± SE 0.0014 strandings/km, and a steady rise was observed in rate of reported strandings after 2010. A seasonal trend was observed as well, with a peak in the month of September (sr = 0.0061 ± SE 0.0016 strandings/km), i.e., towards the end of monsoon season, and lowest strandings were recorded in the month of June (sr = 0.0016 ± SE 0.006 strandings/ km) (Fig. 5).Figure 5Temporal patterns (annual and monthly stranding rates / 100 km of coastline) in strandings of marine mammal records obtained from data compiled between years 1975–2017 along east and west coast of India for each group where (a) annual stranding rate and (b) monthly stranding rate for baleen whales (BW); (c) annual stranding rate and (d) monthly stranding rate for dolphins and finless porpoise (DFP); (e) annual stranding rate and (f) monthly stranding rate for sperm and beaked whales (SBW) and (g) annual stranding rate and (h) monthly stranding rate for dugongs.Full size imageThe mean stranding rate of BW on the east coast through 1975–2017 was 0.0013 ± SE 0.0017 strandings/km, but no specific trends were observed according to years or seasons. Stranding rates of BW did not differ between east and west coast (Mann–Whitney U test, U = 390, U standardized = -0.025, p value  > 0.05).The stranding rates of SBW differed significantly along both the coasts (Mann Whitney U test, U = 192, U standardized = 0.0, p value  More