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A global picture of biological invasion threat on islands


Biological invasions are among the main drivers of biodiversity losses. As threats from biological invasions increase, one of the most urgent tasks is to identify areas of high vulnerability. However, the lack of comprehensive information on the impacts of invasive alien species (IAS) is a problem especially on islands, where most of the recorded extinctions associated with IAS have occurred. Here we provide a global, network-oriented analysis of IAS on islands. Using network analysis, we structured 27,081 islands and 437 threatened vertebrates into 21 clusters, based on their profiles in term of invasiveness and shared vulnerabilities. These islands are mainly located in the Southern Hemisphere and many are in biodiversity hotspots. Some of the islands share similar characteristics regarding their connectivity that could be useful for understanding their response to invasive species. The major invaders found in these clusters of islands are feral cats, feral dogs, pigs and rats. Our analyses reveal those IAS that systematically act alone or in combination, and the pattern of shared IAS among threatened species, providing new information to implement effective eradication strategies. Combined with further local, contextual information this can contribute to global strategies to deal with IAS.

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Fig. 1: Bipartite IAS-threatened species and islands network.
Fig. 2: Interaction network betweeen IAS and threatened species and number of species that could benefit from removal of IAS.
Fig. 3: Examples of network characteristics.

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  1. Kier, G. et al. Global patterns of plant diversity and floristic knowledge. J. Biogeogr. 32, 1107–1116 (2005).

    Article  Google Scholar 

  2. Bellard, C., Cassey, P. & Blackburn, T. M. Alien species as a driver of recent extinctions. Biol. Lett. 12, 20150623 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  3. Bellard, C., Genovesi, P. & Jeschke, J. M. Global patterns in threats to vertebrates by biological invasions. Proc. R. Soc. B 283, 20152454 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  4. Jones, H. P. et al. Invasive mammal eradication on islands results in substantial conservation gains. Proc. Natl Acad. Sci. USA 113, 4033–4038 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Nogales, M. et al. Feral cats and biodiversity conservation: the urgent prioritization of island management. Bioscience 63, 804–810 (2013).

    Article  Google Scholar 

  6. Helmstedt, K. J. et al. Prioritizing eradication actions on islands: it’s not all or nothing. J. Appl. Ecol. 53, 733–741 (2016).

    Article  Google Scholar 

  7. Dawson, J. et al. Prioritizing islands for the eradication of invasive vertebrates in the United Kingdom overseas territories. Conserv. Biol. 29, 143–153 (2015).

    Article  PubMed  Google Scholar 

  8. Early, R. et al. Global threats from invasive alien species in the twenty-first century and national response capacities. Nat. Commun. 7, 12485 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. McCreless, E. E. et al. Past and estimated future impact of invasive alien mammals on insular threatened vertebrate populations. Nat. Commun. 7, 12488 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  10. Gallardo, B., Clavero, M., Sánchez, M. I. & Vilà, M. Global ecological impacts of invasive species in aquatic ecosystems. Glob. Change Biol. 22, 151–163 (2016).

  11. Kumschick, S. et al. Ecological impacts of alien species: quantification, scope, caveats, and recommendations. Bioscience 65, 55–63 (2015).

    Article  Google Scholar 

  12. Carrion, V., Donlan, C. J., Campbell, K. J., Lavoie, C. & Cruz, F. Archipelago-wide island restoration in the Galápagos Islands: reducing costs of invasive mammal eradication programs and reinvasion risk. PLoS ONE 6, e18835 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Courchamp, F., Chapuis, J.-L. & Pascal, M. Mammal invaders on islands: impact, control and control impact. Biol. Rev. Camb. Philos. Soc. 78, 347–383 (2003).

    Article  PubMed  Google Scholar 

  14. Berman, M. et al. Overview of the distribution, habitat association and impact of exotic ants on native ant communities in New Caledonia. PLoS ONE 8, e67245 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Myers, N., Mittermeier, R. A., Mittermeier, C. G., Da Fonseca, G. A. & Kent, J. Biodiversity hotspots for conservation priorities. Nature 403, 853–858 (2000).

    Article  CAS  PubMed  Google Scholar 

  16. Sloan, S., Jenkins, C. N., Joppa, L. N., Gaveau, D. L. A. & Laurance, W. F. Remaining natural vegetation in the global biodiversity hotspots. Biol. Conserv. 177, 12–24 (2014).

    Article  Google Scholar 

  17. Bonnaud, E. et al. The diet of feral cats on islands: a review and a call for more studies. Biol. Invasions 13, 581–603 (2011).

    Article  Google Scholar 

  18. Medina, L. I. X. M., Bonnaud, E., Vidal, E. & Tershy, B. R. A global review of the impacts of invasive cats on island endangered vertebrates. Glob. Change Biol. 17, 3503–3510 (2011).

    Article  Google Scholar 

  19. Jones, H. P. et al. Severity of the effects of invasive rats on seabirds: a global review. Conserv. Biol. 22, 16–26 (2008).

    Article  PubMed  Google Scholar 

  20. Glen, A. S. et al. Eradicating multiple invasive species on inhabited islands: the next big step in island restoration? Biol. Invasions 15, 2589–2603 (2013).

    Article  Google Scholar 

  21. Keitt, B. et al. Best practice guidelines for rat eradication on tropical islands. Biol. Conserv. 185, 17–26 (2015).

    Article  Google Scholar 

  22. Bergstrom, D. M. et al. Indirect effects of invasive species removal devastate World Heritage Island. J. Appl. Ecol. 46, 73–81 (2009).

    Article  Google Scholar 

  23. Rayner, M. J., Hauber, M. E., Imber, M. J., Stamp, R. K. & Clout, M. N. Spatial heterogeneity of mesopredator release within an oceanic island system. Proc. Natl Acad. Sci. USA 104, 20862–20865 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Lips, K. R. Overview of chytrid emergence and impacts on amphibians. Phil. Trans. R. Soc. Lond. B 371, 20150465 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  25. B. Keitt et al. in Island Invasives: Eradication and Management (eds Veitch, C. R., Clout, M. N. & Towns, D. R.) 74–77 (IUCN, Gland, 2011).

  26. Hoffmann, B. D., Luque, G. M., Bellard, C., Holmes, N. D. & Donlan, J. Improving invasive ant eradication as a conservation tool: a review. Biol. Conserv. 198, 37–49 (2016).

    Article  Google Scholar 

  27. Spatz, D. R. et al. The biogeography of globally threatened seabirds and island conservation opportunities. Conserv. Biol. 28, 1282–1290 (2014).

    Article  PubMed  Google Scholar 

  28. Doherty, T. S., Dickman, C. R., Nimmo, D. G. & Ritchie, E. G. Multiple threats, or multiplying the threats? Interactions between invasive predators and other ecological disturbances. Biol. Conserv. 190, 60–68 (2015).

    Article  Google Scholar 

  29. The IUCN Red List of Threatened Species. (IUCN, Gland, 2015);

  30. Bird Species Distribution Maps of the World. Version 4.0. (BirdLife International, Cambridge and NatureServe, Arlington, 2014);

  31. Global Invasive Species Database (IUCN/SSC Invasive Species Specialist Group, 2016);

  32. Mace, G. M. et al. Quantification of extinction risk: IUCN’s system for classifying threatened species. Conserv. Biol. 22, 1424–1442 (2008).

    Article  PubMed  Google Scholar 

  33. Salafsky, N. et al. A standard lexicon for biodiversity conservation: unified classifications of threats and actions. Conserv. Biol. 22, 897–911 (2008).

    Article  PubMed  Google Scholar 

  34. Vilhena, D. & Antonelli, A. A network approach for identifying and delimiting biomes. Nat. Commun. 6, 6848 (2014).

    Article  Google Scholar 

  35. Rosvall, M. & Bergstrom, C. T. Multilevel compression of random walks on networks reveals hierarchical organization in large integrated systems. PLoS ONE 6, e18209 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Graham, J. I. M. et al. Vision of a cyberinfrastructure for nonnative, invasive species management. Bioscience 58, 263–268 (2008).

    Article  Google Scholar 

  37. Lancichinetti, A. & Fortunato, S. Community detection algorithms: a comparative analysis. Phys. Rev. E 80, 056117 (2009).

    Article  Google Scholar 

  38. Aldecoa, R. et al. Exploring the limits of community detection strategies in complex networks. Sci. Rep. 3, 2216 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  39. Rosvall, M., Axelsson, D. & Bergstrom, C. T. The map equation. Eur. Phys. J. Spec. Top. 178, 13–23 (2009).

    Article  Google Scholar 

  40. Rosvall, M. & Bergstrom, C. T. Maps of random walks on complex networks reveal community structure. Proc. Natl Acad. Sci. USA 105, 1118–1123 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Tylianakis, J. M., Laliberte, E., Nielsen, A. & Bascompte, J. Conservation of species interaction networks. Biol. Conserv. 143, 2270–2279 (2010).

    Article  Google Scholar 

  42. Pluess, T. et al. When are eradication campaigns successful? A test of common assumptions. Biol. Invasions 14, 1365–1378 (2012).

    Article  Google Scholar 

  43. Wickham, H. ggplot2: Elegant Graphics for Data Analysis (Springer, New York, 2009);

  44. Bivand, R. & Lewin-Koh, N. maptools: Tools for Reading and Handling Spatial Objects. R package version 0.9-2 (2016);

  45. Csárdi, G. & Nepusz, T. The igraph Software Package for Complex Network Research (InterJournal, 2006);

  46. Wickham, H. & Francois, R., Henry, L. & Müller, K. dplyr: A Grammar of Data Manipulation. R package version 0.5.0 (2015);

  47. Bastian, M. & Heymann, S. gephi: an open source software for exploring and manipulating networks (2009);

  48. Mittermeier, R. A. A. et al. Hotspots Revisited: Earth’s Biologically Richest and Most Endangered Ecoregions (CEMEX, Mexico City, 2004).

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C.B. was supported by an Axa Fellowship. We thank S. Pagad; C. Leclerc and J. Jeschke for their comments on an earlier version of the manuscript; F. Courchamp for fruitful discussions.

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C.B. and J.-F.R. conceived and designed the study with contributions by G.M.M. J.-F.R. and C.B. carried out the analyses, B.L. provided the initial version of the computing code. C.B. and J.-F.R. wrote the first draft of the manuscript and all authors substantially contributed to interpreting and writing the manuscript.

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Correspondence to Céline Bellard.

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Bellard, C., Rysman, JF., Leroy, B. et al. A global picture of biological invasion threat on islands. Nat Ecol Evol 1, 1862–1869 (2017).

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