An Assessment of Wakkerstroom Wetland and Its Vegetation Communities from 1938 to 2019

Abstract

There are few studies on the size and changes in species composition over time for wetlands in South Africa. Techniques such as remote sensing have become popular in assisting the development of management plans due to their spatio-temporal advantages and easily reproducible vegetation and land cover maps. The Wakkerstroom wetland was examined using aerial photog-raphy to examine possible changes in the extent and Landsat imaging was used to map its vegetation communities. To assess the distribution of vegeta-tion types on Wakkerstroom wetland, in situ recording of vegetation types and their GPS coordinates was conducted and a Random Forest model was used to predict vegetation types from Landsat pixel spectra across the wetland extent. As calculated from aerial photographs, the Wakkerstroom wetland has increased in extent by 0.483 km2 from 1938 to 2009. The P. australis popula-tion density increased significantly over time (r = 0.89), whereas the T. cap-ensis population density had a strong negative correlation over time (r = −0.70). A strong negative relationship between P. australis and T. capensis existed (r = −0.88). A need exists to introduce a management tool that will create a greater mosaic of vegetation communities thus ensuring a greater bird, reptile, and amphibian diversity.