Rare but important: Perturbations to uncommon species can have a large impact on the structure of ecological communities

Abstract

Introduction Climate change, overexploitation of natural populations, invasive species, and habitat degradation are affecting species and ecosystems all over the world on a scale that is predicted to lead to the sixth mass extinction (Barnosky et al., 2011). Such dramatic perturbations to ecological communities are likely to affect the structure, functioning, and stability of ecosystems (Montoya et al., 2006; Pereira et al., 2010: Isbell et al., 2011; Hooper et al., 2012), invoking the important question if changes to, or even loss of, some species can be expected to have more far-reaching consequences than others. Or put another way: are some species more important than others in upholding the structure and functioning of ecological systems? Despite the urgency of this question, our understanding of the contribution of different species to community structure and functioning is incomplete and contradictory. For example, some models describing patterns in ecosystems suggest that all species are “equivalent” (i.e., differences are neutral with respect to community properties, e.g., MacArthur and Wilson, 1967; Hubbell, 2001), while others suggest that some nodes are disproportionately important for maintaining community structure and functioning (Saavedra et al., 2011) and can be considered keystone species (Paine, 1966, 1969; Cottee-Jones and Whittaker, 2012). Due to the practical and ethical constraints associated with perturbing species in real ecosystems, many researchers have used theoretical approaches to address these questions, for example studying the effect of small as well as large disturbances (Curtsdotter et al., 2011; Berg et al., 2015; Jonsson et al., 2015) to different kinds of species in model communities and monitoring the response. Theoretical studies of species extinctions have among other things documented the obvious importance of highly connected species for the permanence of the remaining food web (Eklöf and Ebenman, 2006), and identified large body size, high trophic position, low vulnerability, or low numerical abundance (Berg et al., 2015) as traits of potential keystone species that, if lost, are likely to cause cascades of secondary extinctions (Borrvall et al., 2000; Ebenman and Jonsson, 2005). Here we also use a theoretical approach to look for species that, when perturbed, will affect a community more than others, and analyze if there are species with particular attributes whose ecological importance currently are under-appreciated. One such attribute might be the abundance of a species.

Published in

Title: Adaptive Food Webs : Stability and Transitions of Real and Model Ecosystems
Publisher: Cambridge University Press

SLU Authors

• Jonsson, Tomas

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • Linköping University
  • University of Skövde

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1017/9781316871867.021
• ISBN: 978-1-107-18211-0
• eISBN: 978-1-316-87186-7

Permanent link to this page (URI)

https://res.slu.se/id/publ/130299