Resilience of South African communal grazing lands after the removal of high grazing pressure

Harrison, Y. A.; Shackleton, Charlie M.

doi:10.1002/(sici)1099-145x(199905/06)10:3<225::aid-ldr337>3.3.co;2-k

Cited by 8 publications

(12 citation statements)

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“…grazing or hay harvest) did not alter the influence of the focal soil disturbance. This might reflect that North American grasslands, like many others, evolved with herbivory and are well adapted to defoliation disturbance, a historically relevant extensive disturbance (Garcia 1992;Hartnett et al 1996;Harrison and Shackleton 1999;Biondini et al 1998;Limb et al 2009;Bartolome et al 2004).…”

Section: Discussionsupporting

confidence: 89%

Restoring biopedturbation in grasslands with anthropogenic focal disturbance

et al. 2010

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Grassland ecosystems evolved with natural disturbance events on multiple spatial scales in which focal, fine-scale soil disturbance by animals often was imbedded within large-scale grazing disturbance. The resulting plant communities adapted to both broad-scale and fine-scale disturbance that resulted in species-rich plant communities. These natural disturbance regimes have been largely replaced by anthropogenic disturbance. While we generally understand grassland response to modern grazing practices, we know much less about plant community response to soil disturbance imbedded within non-focal grazing. Therefore, we used a tracked vehicle to focally disturb soil in a North American mesic mixed prairie that was either undisturbed prairie or prairie with a recent history of disturbance from either grazing or haying. Successional trajectory and recovery time following focal soil disturbance was similar between grazed and hayed plant communities. Species composition did not differ (P \ 0.05) between grazed or hayed prairie and the respective undisturbed prairie. Plant species richness and bare ground increased (P \ 0.05) following focal soil disturbance in both grazed and hayed communities, but focal soil disturbance combined with either grazing or haying did not change either plant species richness or bare ground more than (P [ 0.05) focal soil disturbance alone. Also, the effect of focal soil disturbance was shortlived with recovery in two growing seasons. Our results suggest that anthropogenic focal soil disturbance is a reasonable mechanism to restore soil disturbance to the grassland ecosystem.

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Section: Discussionsupporting

confidence: 89%

Restoring biopedturbation in grasslands with anthropogenic focal disturbance

et al. 2010

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“…Other communal rangeland systems have shown similar persistence despite predictions of imminent collapse (Mace 1991;Harrison and Shackleton 1999;Sullivan and Rohde 2002;Vetter 2009) and many regard communal tenure as a viable system (Scogings et al 1999). This study confirms some other studies in the Grassland Biome that show that plant species richness need not decline under heavy communal grazing, and can even increase significantly at plot scale, the latter as shown by this study.…”

Section: Discussionmentioning

confidence: 99%

Can heavy grazing on communal land elevate plant species richness levels in the Grassland Biome of South Africa?

Rutherford

Powrie

2011

Plant Ecol

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A common perception, particularly in South Africa, is that heavily and continuously grazed communal land leads to degradation and loss of plant diversity when compared to commercial rangeland farming or conservation areas. We focus on whether this applies to the Grassland Biome of South Africa and whether the opposite can occur, namely, an increase in plant species richness under heavy grazing. A study of a contrast between a communal area of the former Ciskei and a neighbouring nature reserve showed that intense utilization under communal use led to a significant increase in plant species richness. However, this increase was scale-dependent with the greatest significant difference occurring at sample plot scale (50 m 2 ) but converging at the broader scale of the whole study site. Species that increased with heavy grazing included those from arid Karroid areas as well as some from more mesic grassland and savanna areas. The contribution of beta diversity to gamma diversity across the grazing contrast was relatively low which reflects the relatively high proportion of species shared between treatments. Total plant canopy cover declined sharply with heavy grazing. In terms of plant canopy cover, grazing favoured annual over perennial plants, prostrate over erect plants, and stoloniferous over tussock plant architecture. This pattern was not supported when expressed in terms of number of species belonging to these grazing response groups or traits.

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“…It was a degraded natural grazing area with clear evidence of land degradation, such as bare soil, isolated tall grass tussocks and the presence of pedestals and exposed roots, while other patches are entirely covered by vegetation. The area is a typical open communal grazing land with no fertilization, where the common practice is to burn the grass in order to regenerate it and to prevent the rangeland from becoming closed stands of woody species (Harrison and Shackleton, 1999).…”

Section: Methodsmentioning

confidence: 99%