Post Shallow-landslide Habitat Disturbance and Vegetation Recovery Status in a Wet Montane Wildlife Sanctuary in Chimanimani, Zimbabwe

Abstract

Landslides are a form of slope failure that may lead to soil and vegetation removal on the earth surface. This study seeks to assess the vegetation recovery status and succession in areas affected by the Tropical Cyclone Idai induced shallow landslides in Eland Sanctuary Park that occurred in March, 2019. Site observations and floristic surveys were conducted to assess the extent of woody vegetation recovery and plant successional process. Plant diversity was assessed by estimating the Shannon‒Wiener index, whereas species richness was computed using the Menhinick’s index. Fifty-eight shallow landslide sites were recorded in the southwestern part of the study area. The areas affected are mostly located in open woodland at elevations between 1418m and 1673m and slopes ranging between 20–70 degrees. Areas affected by shallow landslides summed up to 1.850km2 in size. The sites are associated with loose soils of clay-silt and loam dominated on impervious substrata. Across the sites affected, twenty-nine plant species were recorded from the plots sampled. Among the plants species recorded are Pteridium aquilinum, Pinus patula, Helichrysum spp, Vernonathura polyanthes, Cyperus iria and Acacia mearnsii. The Shannon index calculation showed medium diversity (Shannon (H) = 2.474). The species richness (Menhinick index) was 0.5233. The woody plants species recorded were mostly seedlings, although there was no significant differences in numbers with recorded bushes and mature trees (Mann‒Whitney test at p = 0.05, where the p value = 0.2203). There was also no significant difference in number of colonisers from woody invasive plants of Pinus patula, Vernonathura polyanthes and Acacia mearnsii (H =4.57; DF = 2; p value = 0.102, p = 0.05) recorded across the sampled plots. Active habitat restoration of the affected sites using native woody species is recommended.