Influence of patch formation in determining the stocking rate for southern African grasslands

Kellner, Klaus; Bosch, Ockie J.H.

doi:10.1016/s0140-1963(18)30661-x

Cited by 40 publications

(21 citation statements)

References 7 publications

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“…Pastor et al (1998) quantified the spatial heterogeneity of both grazing and vegetation, and demonstrated that spatial heterogeneity in consumption by moose created similar spatial heterogeneity in vegetation. Eight studies (Bakker et al 1983;Coppock et al 1983b;McNaughton 1984;Ring et al 1985;Kellner and Bosch 1992;Lutge et al 1996;Cid and Brizuela 1998;Posse et al 2000), representing seven different ecosystems, documented patch grazing by domestic or wild ungulates. Presumably because of positive feedbacks with forage quality (Hobbs and Swift 1988), the grazers foraged in previously grazed areas, producing dramatic changes in vegetation structure and sometimes composition.…”

Section: Increases In Spatial Heterogeneity Following Grazingmentioning

confidence: 99%

The effect of grazing on the spatial heterogeneity of vegetation

2001

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Grazing can alter the spatial heterogeneity of vegetation, influencing ecosystem processes and biodiversity. Our objective was to identify why grazing causes increases in the spatial heterogeneity of vegetation in some cases, but decreases in others. The immediate effect of grazing on heterogeneity depends on the interaction between the spatial pattern of grazing and the pre-existing spatial pattern of vegetation. Depending on the scale of observation and on the factors that determine animal distribution, grazing patterns may be stronger or weaker than vegetation patterns, or may mirror the spatial structure of vegetation. For each possible interaction between these patterns, we make a prediction about resulting changes in the spatial heterogeneity of vegetation. Case studies from the literature support our predictions, although ecosystems characterized by strong plant-soil interactions present important exceptions. While the processes by which grazing causes increases in heterogeneity are clear, how grazing leads to decreases in heterogeneity is less so. To explore how grazing can consistently dampen the fine-scale spatial patterns of competing plant species, we built a cell-based simulation model that features two competing plant species, different grazing patterns, and different sources of vegetation pattern. Only the simulations that included neighborhood interactions as a source of vegetation pattern produced results consistent with the predictions we derived from the literature review.

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Section: Increases In Spatial Heterogeneity Following Grazingmentioning

confidence: 99%

The effect of grazing on the spatial heterogeneity of vegetation

2001

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“…Degradation generally starts with the formation of smaller areas or patches which expand or join together to form large bare and denuded areas in the long-term (Kellner and Bosch, 1992). In terms of rangelands, degradation means the reduction or loss of biodiversity and productivity, increasing the rate of erosion and reducing the ability to produce sustainable activities pertinent to the system of land use (Van Oudtshoorn, 1994;Okin, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Realising that conservation of existing ecosystems is simply not enough to ensure the future of living populations, and that degraded systems will not recover by natural successional processes in arid and semi-arid systems, restoration has become an absolute necessity (Friedel, 1991;Kellner and Bosch, 1992;De Wet, 2001). Restoration ecology deals with the scientific and ecological background of natural management practices aiming at the re-establishment of vegetation, which have disappeared.…”

Section: Introductionmentioning

confidence: 99%

Restoring degraded patches in a semi-arid rangeland of South Africa

Berg

Kellner

2005

Journal of Arid Environments

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“…Vegetation patterns in semi-arid grasslands were formed through selective grazing by herbivores (Kellner & Bosch, 1992). In terms of vegetation composition, a number of patterns emerged on both sides of the fence (Table 1 and Table 2).…”

Section: Discussionmentioning

confidence: 99%