Harvesting distance effect on tree species diversity in traditional agroforestry landscape : a case of Vhembe Biosphere Reserve in South Africa

Abstract

Traditional agroforestry has been recognised to contribute to biodiversity conservation; however, biodiversity strategies often lack information about drivers of tree species diver sity loss, which is crucial for decision-making. Anthropogenic disturbance has positive and negative efects on tree species richness and diversity. This study was conducted in Vhembe Biosphere Reserve, Limpopo Province, and used distance from the nucleus of the community to the forest as a parameter to assess tree species richness and diversity. Vege tation data were collected using three transects of 150 m in each distance level and sampled a total area of 1000 m2 by sampling fve rectangular plots of 20 m2×10 m2 (200 m2 ). Data analysis was conducted using Chao1, PERMANOVA, nMDS, PERMDISP, DISTLIM, dbRDA and SIMPER. The fndings are in consonant with distance decay of community similarity hypotheses, with estimated tree species richness of 76, 93 and 95 species in an immediate distance, intermediate distance and far distance, respectively. Moreover, the highest species variation was observed at an intermediate distance, which indicates that there is greater species composition at an intermediate distance compared to immediate and far distances. The results confrm that the distance and associated factors have major detrimental efects on tree species richness and biodiversity in traditional agroforestry land scapes. Harvesting of provisioning ecosystem services is found and known to be extremely high in the study area. Efective interventions such as planting indigenous trees and con serving the existing vegetation must be implemented to reduce and halt overexploitation.