Species-rich ecosystems are vulnerable to cascading extinctions in an increasingly variable world

Abstract

Global warming leads to increased intensity and frequency of weather extremes. Such increased environmental variability might in turn result in increased variation in the demographic rates of interacting species with potentially important consequences for the dynamics of food webs. Using a theoretical approach, we here explore the response of food webs to a highly variable environment. We investigate how species richness and correlation in the responses of species to environmental fluctuations affect the risk of extinction cascades. We find that the risk of extinction cascades increases with increasing species richness, especially when correlation among species is low. Initial extinctions of primary producer species unleash bottom-up extinction cascades, especially in webs with specialist consumers. In this sense, species-rich ecosystems are less robust to increasing levels of environmental variability than species-poor ones. Our study thus suggests that highly species-rich ecosystems such as coral reefs and tropical rainforests might be particularly vulnerable to increased climate variability.

Keywords

Biodiversity; climate change; ecological networks; environmental variability; extinction cascades; food web; species interactions; stability; stochastic models; weather extremes

Published in

Ecology and Evolution
2012, Volume: 2, number: 4, pages: 858-874

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1002/ece3.218

Permanent link to this page (URI)

https://res.slu.se/id/publ/84722