Spatial Heterogeneity and Irreversible Vegetation Change in Semiarid Grazing Systems

Title
Spatial Heterogeneity and Irreversible Vegetation Change in Semiarid Grazing Systems
Publication Date
2002
Author(s)
va de Koppel, J
Rietkerk, M
Stroosnijder, L
Prins, H
van Langevelde, F
Kumar, L
( author )
OrcID: https://orcid.org/0000-0002-9205-756X
Email: lkumar@une.edu.au
UNE Id une-id:lkumar
Klausmeier, CA
Fryxell, J
Hearne, J
van Andel, J
de Ridder, N
Skidmore, A
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
University of Chicago Press
Place of publication
United States of America
DOI
10.1086/324791
UNE publication id
une:345
Abstract
Recent theoretical studies have shown that spatial redistribution of surface water may explain the occurrence of patterns of alternating vegetated and degraded patches in semiarid grasslands. These results implied, however, that spatial redistribution processes cannot explain the collapse of production on coarser scales observed in these systems. We present a spatially explicit vegetation model to investigate possible mechanisms explaining irreversible vegetation collapse on coarse spatial scales. The model results indicate that the dynamics of vegetation on coarse scales are determined by the interaction of two spatial feedback processes. Loss of plant cover in a certain area results in increased availability of water in remaining vegetated patches through run-on of surface water, promoting within-patch plant production. Hence, spatial redistribution of surface water creates negative feedback between reduced plant cover and increased plant growth in remaining vegetation. Reduced plant cover, however, results in focusing of herbivore grazing in the remaining vegetation. Hence, redistribution of herbivores creates positive feedback between reduced plant cover and increased losses due to grazing in remaining vegetated patches, leading to collapse of the entire vegetation. This may explain irreversible vegetation shifts in semiarid grasslands on coarse spatial scales.
Link
Citation
The American Naturalist, 159(2), p. 209-218
ISSN
1537-5323
0003-0147
Start page
209
End page
218

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