Litter dynamics across browsing-induced fenceline contrasts in succulent thicket, South Africa

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dc.contributor.authorLechmere-Oertel R.G.
dc.contributor.authorKerley G.I.H.
dc.contributor.authorMills A.J.
dc.contributor.authorCowling R.M.
dc.date.accessioned2011-05-15T15:54:49Z
dc.date.available2011-05-15T15:54:49Z
dc.date.issued2008
dc.description.abstractSemi-arid succulent thicket in South Africa has experienced extensive livestock-induced transformation, reflected in extensive structural changes and loss of biodiversity, biomass and soil carbon. The ecological mechanisms contributing to this transformation are not fully understood but are believed to include the breakdown of ecosystem processes including litter production and decomposition, which are rate-limiting steps in nutrient cycling and incorporation of organic matter into the soil. In this study we investigated the effect of transformation on litter production and decomposition in succulent thicket. We measured litter production and decomposition of four dominant perennial woody plants (Euclea undulata, Pappea capensis, Portulacaria afra and Rhus longispina) across replicated fenceline contrasts. Litter production was measured over 14 months using mesh traps. Decomposition was measured over 15 months using a combination of litterbags and leaf packs. Litter production in succulent thicket was very high for a semi-arid system (approaching that of temperate forests), with the leaf- and stem-succulent P. afra contributing the largest component. Transformation caused a significant reduction in litter production at a landscape scale (4126 vs 2881 kg/ha/yr), primarily due to reduced cover of P. afra. Surprisingly, transformation had few significant effects on the rate of decomposition of litter, possibly due to a switch from biotic to abiotic decomposition processes. The perennial vegetation in succulent thicket, particularly P. afra, appears to play a critical role in the maintenance of the ecosystem by facilitating the incorporation of organic matter into soil. Transformation of succulent thicket leads to a disruption of the carbon cycle, ultimately resulting in degradation of the ecosystem. Successful restoration is likely to depend on increasing the rates of organic matter return to soils. P. afra is a potential carbon restoration pump as it is both drought-resistant and easily propagated from cuttings. © 2008 SAAB.
dc.description.versionArticle
dc.identifier.citationSouth African Journal of Botany
dc.identifier.citation74
dc.identifier.citation4
dc.identifier.issn2546299
dc.identifier.other10.1016/j.sajb.2008.04.002
dc.identifier.urihttp://hdl.handle.net/10019.1/9422
dc.subjectbiodiversity
dc.subjectbrowsing
dc.subjectdecomposition
dc.subjectevergreen tree
dc.subjectlitter
dc.subjectnutrient cycling
dc.subjectprimary production
dc.subjectsemiarid region
dc.subjecttransformation
dc.subjectwoody plant
dc.subjectEuclea undulata
dc.subjectHedera
dc.subjectPappea capensis
dc.subjectPortulacaria afra
dc.subjectRhus longispina
dc.titleLitter dynamics across browsing-induced fenceline contrasts in succulent thicket, South Africa
dc.typeArticle
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