Predation and Community Organization

by

Oswald J. Schmitz

• LAST REVIEWED: 30 September 2013
• LAST MODIFIED: 30 September 2013
• DOI: 10.1093/obo/9780199830060-0120

Introduction

Ecological communities can be envisioned as food webs in which species are linked with each other in a network of interconnections. Conceivably, predation is pervasive: all organisms (plants, herbivores, and carnivores) within ecological communities are effectively predators of resources. This article, nevertheless, focuses on one group of predator, namely the largely carnivorous species occupying upper levels of food webs. Carnivores are the charismatic species that inspire awe, fear, and admiration and, thereby, engender conservation concern. Studying predators gives one a deep appreciation for their cunning and adaptability to thrive in their natural environments. Carnivores are ubiquitous components of ecological communities and are instrumental in determining the kinds and abundances of species that coexist within communities as well as the functioning of those systems. However, all of this may be changing as humans increasingly dominate Earth and fragment or convert their habitats to other purposes, exploit them as a resource (e.g., fisheries), and extirpate them because of perceived threats to human livelihoods and well-being (livestock depredation). This article gives the reader an appreciation of the vast scientific understanding about the integral roles predators play in sustaining communities. The article takes us from foundational efforts to conceptualize the importance of predation, relative to other ecological interactions, to early experimental efforts designed to quantify those effects. With increasing understanding comes a greater desire to know mechanisms of effect, which requires advancement of experimental methods and research programs. Much of the article, therefore, highlights efforts to conceptualize and quantify the mechanisms of predator effects in communities, including understanding how predator foraging traits and behaviors determine the kind of prey that are attacked and consumed and the responses of prey to predation threat. Because of food web connections, predators will also have ripple effects on the resources of the prey because of changes in prey abundances and prey anti-predator behaviors. The article highlights how those ripple effects propagate through communities. The bibliography also introduces research aiming to address modern questions of the role of predator biological diversity in sustaining the functioning of natural ecosystems and in helping to control pest outbreaks in agricultural systems. It ends with modern efforts to change how we think about predator impacts on communities and ecosystems in a world increasingly dominated by humans that demands fundamental changes to theories of community dynamics and how we conserve predator species and the larger systems of which they are an integral part.

General Overviews

The following resources offer a quick glimpse into the kinds of issues that have been addressed in the study of predation and community organization. A pervasive issue has been to discern the degree to which two important mechanisms—competition and predation—determine community organization. Sih, et al. 1985 and Chase, et al. 2002 provide synthetic perspectives from two different periods in the history of the field and, as such, give the reader a sense of how understanding has evolved over time. Kerfoot and Sih 1987 and Barbosa and Castellanos 2005 are edited compendia, again covering the same span of history of the field, that provide an overview of the central issues addressed in the study of predation and community organization and how those issues have evolved over time.

• Barbosa, Pedro, and Ignacio Castellanos, eds. 2005. Ecology of predator-prey interactions. New York: Oxford Univ. Press.

  A comprehensive volume that offers conceptual and empirical understanding of the organismal behavior, population biology, community ecology, and issues of biological conservation arising in modern studies of predation and community organization.

• Chase, Jonathan M., Peter A. Abrams, James P. Grover, et al. 2002. The interaction between predation and competition: A review and synthesis. Ecology Letters 5.2: 302–315.

  DOI: 10.1046/j.1461-0248.2002.00315.x

  The paper advances some of the early principles in Sih, et al. 1985 by exploring the mechanisms of, and interplay among, competition and predation in communities and how best to measure the effects in experimental research.

• Kerfoot, Charles W., and Andrew Sih, eds. 1987. Predation: Direct and indirect effects on aquatic communities. Hanover, NH: Univ. Press of New England.

  A foundational volume that addresses not only the kinds of indirect effects that predators may propagate within communities, but also the morphological and behavioral traits and mechanisms underlying predator and prey species interactions.

• Sih, Andrew, Philip Crowley, Mark McPeek, James Petranka, and Kevin Strohmeier. 1985. Predation, competition, and prey communities: A review of field experiments. Annual Review of Ecology and Systematics 16:269–311.

  DOI: 10.1146/annurev.es.16.110185.001413

  A classic synthesis that raises awareness about the importance of predation in structuring ecological communities. The paper served to launch explorations into more than just the role of competitive interactions as a driver of community structure.