Understanding how species extinctions affect the stability of ecosystems is fundamental to the prediction of future biodiversity loss and to ensuring the reliable provision of ecosystem services. In a paper published recently in Ecology Letters*, we (researchers from the School of Natural Sciences in Trinity College Dublin and the Trinity Centre for Biodiversity Research, together with collaborators from Northern Ireland, Spain and Switzerland) show that the destabilising effect of biodiversity loss is likely to be considerably greater than thought previously.
Ecosystem stability has been the subject of hundreds, if not thousands, of papers. It occupies a prominent place in both fundamental and applied ecological research. However, ecological stability is regularly touted as a multifaceted and complex concept. This is because there are many different ways in which we can measure the stability of ecosystems. These include, for example, the variability of systems over time or their ability to resist or recover from disturbances. However, in spite of its multifaceted nature, almost all studies focus only on a single measure to characterise ecosystem stability. Further, the few studies that measured more than one component of stability considered them as independent and therefore analysed them separately, in spite of the fact that they are likely to be related to one another.
Using an experimental study done on a marine rocky shore, we examined the effects of the loss of different consumer species, including both predators and their prey, on multiple distinct components of ecological stability simultaneously. We show for the first time that, even though stability is a relatively simple property of ecological communities, different species contribute in different ways to the maintenance of stability. Moreover, our study also demonstrates that the loss of species from ecosystems can modify and even decouple relationships among components of stability. Ignoring the multifaceted nature of stability therefore risks underestimating significantly the potential of perturbations to destabilize ecosystems. In conclusion, our study indicates that we currently underestimate significantly the overall destabilizing effect of biodiversity loss and thus the true scale of the global extinction crisis that we face.
Author
Ian Donohue: ian.donohue@tcd.ie
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