Land use and climate change implications for biodiversity and habitat loss within the public and private reserves of the Southern Waterberg district, Limpopo

Abstract

The planet is facing a range of environmental issues related to and caused by anthropogenic activities. Biodiversity loss constitutes one of the most significant environmental tragedies of modern times. Climate change and land use changes may have severe consequences for biodiversity, ecosystem services, and habitat loss globally. The impacts of land use change and climate change may also differ between protected areas, and those areas surrounding protected areas. This can occur due to factors such as differences in management and conservation plans, as well as differing land use practices and development. Due to such factors, climate change and land use changes may cause the rate of biodiversity loss to be greater in areas surrounding protected areas, as opposed to within protected areas. The mountainous area known as the Waterberg Biosphere, located in the Southern Waterberg, has rich biodiversity, including more than 5,500 species of plants, 43% of which are endemic to South Africa. The dominant biome in the Southern Waterberg is the Savanna Biome. To investigate these impacts (land use and climate changes) in the Southern Waterberg, a range of mapping and visualisation methods have been implemented and used as well as statistical analysis (Chi-square analysis and linear regression). Two specific locations were the focus of this study, namely the Grootwater Nature Reserve (3.32 ha) and the Welgevonden Game Reserve (28.57 ha), which are located within the Waterberg Biosphere. The Grootwater Nature Reserve (an example of a public reserve), and the Welgevonden Game Reserve (an example of a private reserve) were compared in terms of the extent of habitat/vegetation loss within and surrounding the protected areas. Further, the extent of habitat/vegetation loss within the protected areas in comparison to the surrounding areas (5km buffer) was assessed between 1990 and 2020. Climatic changes (rainfall and temperature trends) were also assessed for the area from 1990 to 2020. Landcover maps (SANLC), Chi-square analysis, and linear regression analysis illustrated this comparison. Landcover data and maps were also used to illustrate the extent of land use changes in the study areas. Statistical analysis was then also introduced to confirm the difference in habitat and vegetation loss within and surrounding the two protected areas, as well as to gauge the relationship between the climatic changes in the area and habitat/vegetation loss within the study sites. The results indicated that both protected areas experienced habitat/vegetation loss to a lesser extent than the surrounding areas. Further, the Welgevonden Game Reserve experienced more habitat/vegetation loss than the Grootwater Nature Reserve. Trend analysis indicated that there was a general increase in average temperatures and decrease in average rainfall from 1990 to 2020 in the area. Statistical analysis suggested that habitat/vegetation loss was most likely due to climatic changes (particularly a decrease in total annual rainfall and increase in monthly maximum temperatures) rather than land use changes.