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9 - Large herbivores as sources of disturbance in ecosystems

Published online by Cambridge University Press:  16 November 2009

By
N. Thompson Hobbs
Edited by
Kjell Danell ,
Roger Bergström ,
Patrick Duncan  and
John Pastor
N. Thompson Hobbs
Affiliation:
Colorado State University
Kjell Danell
Affiliation:
Swedish University of Agricultural Sciences
Roger Bergström
Affiliation:
The Forestry Research Institute of Sweden
Patrick Duncan
Affiliation:
Centre National de la Recherche Scientifique (CNRS), Paris
John Pastor
Affiliation:
University of Minnesota, Duluth
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Summary

INTRODUCTION

Understanding the causes and consequences of spatial heterogeneity in ecosystems has emerged as a fundamental challenge for contemporary ecologists worldwide (Levin 1992, Pickett & Cadenasso 1995, Pascual & Levin 1999, Allen & Holling 2002, Ettema & Wardle 2002, Perry 2002, Hobbs 2003). Abiotic sources of heterogeneity, variation in soils for example, are described relatively easily. A much more difficult task is to understand how spatial heterogeneity arises from biotic interactions (Augustine & Frank 2001, Steinauer & Collins 2001). These biotic sources of spatial variation can give rise to complex feedbacks in ecosystems; feedbacks that shape the operation of ecological processes across scales and levels of organization (e.g. Holling 1992, Pickett et al. 1992, Tilman 1994, Pastor et al. 1997, 1998, Polis et al. 1997, Van Buskirk & Ostfeld 1998, Keeling 1999, Illius & O'Connor 2000, Augustine & Frank 2001, Steinauer & Collins 2001, van de Koppel et al. 2002).

Much effort has been invested in identifying biotic sources of spatial variation in grassland, steppe and forested ecosystems, particularly in describing the reciprocal role played by large herbivores in responding to landscape heterogeneity and in creating it (Jefferies et al. 1994, Laca & Ortega 1995, Scoones 1995, Hobbs 1996, 1999, Pastor et al. 1997, 1998, 1999, Fuhlendorf & Smeins 1999, Adler et al. 2001, Augustine & Frank 2001, Steinauer & Collins, 2001). Herbivores respond to spatial heterogeneity in plants across a range of scales by selecting locations for feeding and resting (Senft et al.

Type
Chapter
Information
Large Herbivore Ecology, Ecosystem Dynamics and Conservation , pp. 261 - 288
Publisher: Cambridge University Press
Print publication year: 2006

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