Patterns and drivers of mammal diversity across the Waterberg mountain catchment area, South Africa

Abstract

Mammal diversity varies spatially and temporally globally, influenced partly by natural and human-induced disturbances on ecosystems. In South Africa, there has been a significant shift in land use from agriculture and livestock farming to wildlife husbandry and breeding. This transition, driven by economic incentives and a move from pastoralism to conservation, has altered wildlife "ownership" and production practices. This study, part of the Foundation Biodiversity Information Program Waterberg Mountain Catchment (FBIP WMC), focuses on the Waterberg region in Limpopo, South Africa. The area is characterized by diverse habitats, topography, and vegetation, yet it remains relatively understudied. The uniqueness of the Waterberg makes it a critical area for conservation efforts. The objectives of this study were to determine the current presence of mammal species compared to historical records, assess the richness, abundance, and diversity of mammal species across the Waterberg, and analyze the fine-scale response patterns of ungulate species to vegetation clearing practices on two privately owned game reserves. This study aims to provide a better understanding of mammal biodiversity in the Waterberg and highlight the potential impacts of land tenure and vegetation manipulation on local mammal populations. Firstly, historical data from virtual museums, online databases and published literature were used to determine the mammal species that could be found in the area. Data obtained from camera traps deployed across 18 properties of the Waterberg were then used to determine the current diversity of mammal species present in the area, which could be determined using camera trap surveys. The FBIP WMC study matched the historically derived data (n = 62 mammals) with some additions and some species missing from the current camera trap survey. Additionally, this study highlights the importance of pairing digital/ virtual repositories with data from scientific studies. This integration benefits conservation efforts by providing better information and management strategies, ultimately promoting and safeguarding biodiversity for future generations. Secondly, species richness, abundance, and evenness across the FBIP WMC were assessed. Non-governmental game reserves exhibited the highest species richness, averaging 39 species, followed by nature conservancies with 36 species, and livestock/agricultural properties with 31 species. Species richness observed in the study aligned with Chao2 diversity estimates for most properties. Generalised linear modelling indicated significant variations in species richness across properties, influenced by factors such as dangerous game fence type, game reserve land use, and the Central Sandy Bushveld vegetation type. Privately owned Big-5 game reserves had higher species abundances, while livestock and agricultural properties showed moderate similarity and lower abundances of unmanaged species. State-owned conservancies had some overlap in unmanaged species. Feeding guild analysis revealed that mixed feeders, omnivores, and selective browsers were common, with specific reserves showing unique proportions of bulk grazers and insectivores. Mesocarnivores remained irrespective of the degree of anthropogenic changes, being abundant across all properties. Thirdly, my research investigated the fine-scale response patterns of ungulate species to vegetation clearing practices as a management tool for woody encroachment. There were differences in Vegetation Condition Index (VCI) and Vegetation Condition Assessments (VCA) between Kaingo and Qwabi, with differences in the mix of woody plants, forbs, and grasses. The site where the bulldozer treatment was used on Qwabi had the best VCI for plant quality. Ungulate occupancy differed significantly between treated and untreated sites at Kaingo. Greater Kudu and Plains Zebra were found in both site types, but most other species preferred untreated sites, which showed higher overall occupancy probability. At Qwabi, more ungulate species were observed at treated sites, although four species were absent there. Blue Wildebeest, Impala, and Plains Zebra favoured treated sites, while Bushbuck showed no site preference. The interaction of VCI and distance to water did not influence individual species’ occupancies. In conclusion, the combined approach of using a large-scale camera trap study, such as the FBIP WMC project, as well as a small-scale study, such as the herbivore response study, is essential for designing, developing, and implementing effective conservation and management plans that promote the longevity and success of mammal populations and ultimately the ecosystems they inhabit. By using both approaches, researchers can improve recommendations to landowners and managers, promote effective habitat restoration, and ensure the conservation of biodiversity in the face of increasing human pressure on the environment.