Trophically Unique Species Are Vulnerable to Cascading Extinction

Understanding which species might become extinct and the consequences of such loss is critical. One consequence is a cascade of further, secondary extinctions. While a significant amount is known about the types of communities and species that suffer secondary extinctions, little is known about the consequences of secondary extinctions for biodiversity. Here we examine the effect of these secondary extinctions on trophic diversity, the range of trophic roles played by the species in a community. Our analyses of natural and model food webs show that secondary extinctions cause loss of trophic diversity greater than that expected from chance, a result that is robust to variation in food web structure, distribution of interactions strengths, functional response, and adaptive foraging. Greater than expected loss of trophic diversity occurs because more trophically unique species are more vulnerable to secondary extinction. This is not a straightforward consequence of these species having few links with others but is a complex function of how direct and indirect interactions affect species persistence. A positive correlation between a species’ extinction probability and the importance of its loss defines high‐risk species and should make their conservation a priority

The contribution of rare species to a community's resilience

The BES Quantitative Ecology SIG, St Andrews, Scotland, 9 July 2018Theoretical results for generalised Lotke-Volterra systems that demonstrate the role of rare species in determining the characteristic return time of the system.Science Foundation Irelan

The contribution of rare species to a community\u27s resilience

The BES Quantitative Ecology SIG, St Andrews, Scotland, 9 July 2018Theoretical results for generalised Lotke-Volterra systems that demonstrate the role of rare species in determining the characteristic return time of the system.Science Foundation Irelan

Appendix D. A figure showing the relationship between redundancy and average equilibrium densities of basal, intermediate, and top species.

A figure showing the relationship between redundancy and average equilibrium densities of basal, intermediate, and top species

Appendix B. Tables summarizing the statistics of the risk curves for the communities obtained from the deterministic and stochastic models.

Tables summarizing the statistics of the risk curves for the communities obtained from the deterministic and stochastic models

Appendix A. Information on the permanence criterion.

Information on the permanence criterion