Harvesting impacts on commonly used medicinal tree species (<i>Catha edulis</i> and <i>Rapanea melanophloeos</i>) under different land management regimes in the Mpumalanga Lowveld, South Africa

Abstract

Harvesting of products from plants in the wild is widespread throughout southern Africa. Particularly important products are plant parts used in traditional medicine. However, the impacts of harvesting practices are rarely quantified, with as yet insufficient generic rules across species and life forms. This limits the predictive ability to monitor and manage the affected populations. This paper examines the harvesting impact on two popular woody medicinal species used throughout sub-Saharan Africa, namely Catha edulis (Vahl) Forssk. ex Endl. (bushman’s tea) and Rapanea melanophloeos (L.) Mez. (Cape beech). In both species, basal diameters, heights, and the number of size classes in the harvested populations were lower than in unharvested. Densities of harvested populations were higher in both species, including densities of young plants, but the frequency of individuals in larger size classes was lower. The populations of both species being harvested for medicinal products appeared to be withstanding the current levels of harvesting, but the population structure of C. edulis populations being harvested for poles on the roadside and near human settlements had been substantially altered. Despite the resilience of the two species to harvesting for medicinal products, loss of habitat or changes in land use pose a threat to a number of the assessed populations.

Sustainable use of non-timber forest products: Impact of fruit harvesting on Pentadesma butyracea regeneration and financial analysis of its products trade in Benin

“…Stands submitted to high-intensity fruit harvesting were near houses, dwellings, farms and cattle growers' camps while stands submitted to low-intensity fruit harvesting are situated far from them and are only sporadically harvested ( Table 1). The intensity of harvesting of specific plant species often decreases with increasing distance from human settlements, transport routes and decreased accessibility of harvesting sites (Luoga et al, 2000;Botha et al, 2004).…”

“…Their excessive harvesting may have negative impact on species sustainability, especially in long term as Peres et al (2003Peres et al ( , p. 2113 suggest, but also on species genetic diversity through the loss of some genotypes. The intensity of harvesting of specific plant species is influenced by resource abundance, accessibility and market demand (Botha et al, 2004) but also by trade chains structure and gross margins distribution all along trade chains.…”

Population structure of three woody species in four ethnic domains of the sub‐sahel of Burkina Faso

“…Interpretation followed Botha et al . (2004) and Mwavu and Witkowski (2009): constant quotients between successive size‐classes indicate a stable population, while variable quotient values represent an unstable population.…”

“…PI is the sum of the absolute distances between the expected and real location (rank) of all size classes, hence ignoring the relative frequency of different size classes (for details see Wiegand et al ., 2000). PI is higher in a discontinuous SCD than in a continuous, monotonically declining population (Botha et al ., 2004). A monotonically declining population shows a PI equal to zero while a population with a discontinuous SCD (a disturbed population) will have a PI > 0 (Venter and Witkowski, 2010).…”

The effect of harvesting approaches on fruit yield, embelin concentration and regrowth dynamics of the forest shrub, Embelia tsjeriam-cottam, in central India

“…Many workers (Ticktin, 2004;Shackleton et al, 2005) opined that heavy harvesting of fruits/seeds could have long-term detrimental effects on recruitment of new individuals and can bring changes in population structure and dynamics of plants being harvested due to limited regeneration and recruitment. The intensity of harvesting of specific plant species often decreases with increasing distance from human settlements and decreased accessibility of harvesting sites (Botha et al, 2004). At experimental sites, we also observed a difference in regeneration and recruitment at regions proximal to the settlements (perhaps due to an increased level of harvesting and other human mediated disturbances), in PPA the effects seem to be subdued.…”