The recovery of an afromontane forest after slash and burn : a case study from the Nkandla forest.
Year: 2000
Type: dissertation
Abstract: Clear cutting and subsequent agricultural processes lead not only to species loss, but also have \nnegative consequences for soil and water conservation. This study investigated the response \nto, and effect of, deforestation due to shifting cultivation on the Nkandla forest complex \n(NFC), a subtropical Afromontane forest. As a consequence of shifting agriculture, \nabandoned areas are nutrient poor, have depleted seed banks and may lack the ability to \nregenerate into species rich mature forest. The ability of forests to regenerate after disturbance \neffects is extremely important for the maintenance of ecological diversity and the stability of \nforest ecosystems. \nThe present study focused on the recovery of the NFC, after shifting agriculture was \npractised along the forest margins. The NFC was sampled to determine: (1) how vegetation \nstructure, composition and plant species diversity differ between regrowth forest and \nundisturbed forest ; (2) how continued disturbance and subsequent land use affects the rate of \nrecovery and regeneration of secondary forest ; and (3) what species establishment pattern, if \nany, does the path of recovery follow during succession? Four different types of forest were \nsampled, disturbed margin (DM) forest, disturbed interior (DI) forest , undisturbed margin \n(UM) forest and undisturbed interior (UI) forest. \nThe study showed that recovery does occur and that in the NFC recovery patterns (in \nterms of species diversity trends, biomass and basal areas) are similar to those found in other \ntropical and sub-tropical regions. Floristic recovery proceeded in a way that required the \nprerequisite establishment of forest margin tree species that would ultimately lead to a climax \ncondition described by undisturbed interior forest. Unimodal trends were found for stem \ndensity and species richness across all four forest types, with basal area increasing steadily \nfrom disturbed to undisturbed interior forest. These forest types and their floral composition \nand structure described a gradient of decreasing disturbance, with disturbed margin forest \nbeing the most disturbed type. \nContinued harvesting of selected species is detrimental to the survival of these species. \nAnalyses showed that Rapanea melanophloeos, Cassipourea gummiflua, Curtisia dentata, \nOchna natalitia, Olea capensis subsp. macrocarpa and Strychnos henningsii have been overused. \nContinued harvesting could result in critically low densities of these species and even \ntheir local extinction.
Author: W. J. Macpherson
Language: English
Subfield: Nature and Landscape Conservation
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W2341826699