Spatial heterogeneity and irreversible vegetation change in semiarid grazing systems

J. van de Koppel*, M. Rietkerk, F. van Langevelde, L. Kumar, C.A. Klausmeier, J.M. Fryxell, J.W. Hearne, J. van Andel, N. de Ridder, A. Skidmore, L. Stroosnijder, H.H.T. Prins

*Bijbehorende auteur voor dit werk

    OnderzoeksoutputAcademicpeer review

    137 Citaten (Scopus)
    253 Downloads (Pure)

    Samenvatting

    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.

    Originele taal-2English
    Pagina's (van-tot)209-218
    Aantal pagina's10
    TijdschriftAmerican Naturalist
    Volume159
    Nummer van het tijdschrift2
    DOI's
    StatusPublished - feb-2002

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