Seriphium Plumosum Encroachment's Ecological Drivers: Management and Conservation Implications

Abstract

In South Africa's grassland and savanna biomes, Seriphium plumosum is known to be a strongly invasive plant, especially in places that have been degraded. This study examined the effects of biotic and abiotic factors on S. plumosum density, height, and population structure at two locations—Klipiviersberg Nature Reserve (KNR, Gauteng) and Amathole Hogsback Plantation (HP, Eastern Cape), both of which experience significant disturbances. 928 plants were found at each site through field sampling along 9 (100 m) transects using the Point-Centered Quarter technique. Recently burned middle slopes at the HP site had the highest density of S. plumosum, followed by less recently burned top and bottom slopes. On the other hand, at KNR, the middle slope with intermediate grazing had the highest shrub density, followed by the slopes with heavy and minimal grazing, respectively. The HP site showed large numbers of juveniles and young adults, suggesting recent disturbances promoting shrub development, while the KNR population structure was primarily composed of mature plants with few juveniles. Our results demonstrate how disturbances, such as fire and grazing, significantly affect S. plumosum distribution patterns by establishing advantageous "open niches." Site-specific biotic and abiotic variables on shrub proliferation were highlighted by structural equation modeling, which found that disturbance and tree cover were important determinants at HP whereas grass biomass predominated at KNR. Effective land management techniques aimed at reducing shrub encroachment and maintaining biodiversity in similar habitats depend on the valuable insights this study offers into the dynamics of S. plumosum in response to changing environmental conditions.