Anthropogenic impacts on forest mammals in the Southern Mistbelt Forests in the Midlands of KwaZulu-Natal, South Africa.

Abstract

Habitat loss worldwide is a major threat to biodiversity. Forest loss is affected by numerous factors, including natural climate change and anthropogenic disturbances (e.g., logging, habitat conversion or increased fire activity). Forest fragmentation results in reduced patch sizes, increased edge effects, and connectivity between patches negatively impacted. Forest fragmentation effects on species differ, with some considerably more sensitive to these changes than others, often resulting in their local extinction. By monitoring biodiversity, effective conservation measures can be implemented to conserve the biodiversity in these forests. Remote camera traps have become an increasingly popular tool to study wildlife in a reliable, non-invasive way. Firstly, the use of camera traps as a research tool in Africa using a systematic review was determined. This highlighted the countries with studies that used camera traps the most, as well as determined the terrestrial wildlife and habitat types receiving the most focus. The findings from assessing camera trap research in Africa revealed that most studies were conducted in South Africa, with most studies focusing on the occupancy of mammals, with a particular focus being on large carnivores, the majority of which were leopard Panthera pardus. Most studies were conducted in forests, followed by savannah/bushveld. Secondly, the presence of forest mammalian species was assessed in the Southern Mistbelt forests in the Midlands of KwaZulu-Natal, South Africa. These forests are fragmented because of both natural and anthropogenic factors. An extensive camera trapping survey was conducted between October 2020 and April 2021 (wet season), and between May 2021 and September 2021 (dry season), with 14 indigenous forest patches being sampled. A total of 339 camera trap stations were deployed in this study, with microhabitat conditions, in a 20 m radius around each camera trap, collected to determine their impact on bushbuck Tragelaphus scriptus, a diurnal forest specialist, and Cape porcupine Hystrix africaeaustralis, a nocturnal generalist, and how the microhabitat conditions potentially impacted their occupancy between the austral wet and dry seasons. Bushbuck were the most recorded mammalian species recorded during both seasons. Cape porcupine presence was recorded more during the dry season, with various microhabitat variables influencing their occupancy. Cape porcupines, as generalists, likely use the forest food resources during the dry season. Bushbuck presence was lower in state-owned forests, likely because of the hunting activities observed in these forests. Thirdly, data collected from the camera trapping surveys were used to determine the influence of landscape factors, including patch size, landscape configuration (number of neighbouring patches), and patch isolation (distance from mainland patch), on forest mammalian species diversity in forest patches, between the wet and dry seasons. Patch size strongly influenced forest mammalian species richness, which was relatively low, with more species occupying larger patches than smaller patches. Similarly, landscape configuration affected species richness and was generally higher in those forests surrounded by multiple forest patches. Forest isolation, however, did not seem to be particularly impactful in determining forest mammalian species diversity. Overall, this research showed the value of camera traps as a research tool and their effectiveness in studying rare and elusive mammalian species in Africa. Effects of anthropogenic disturbances on various forest mammalian species were highlighted, with activities such as hunting and uncontrolled resource harvesting, such as collection of fuelwood, medicinal plants and building materials by the local communities, impacting the presence of various forest mammalian species, particularly forest specialist species, such as the blue duiker Philantomba monticola. The importance of maintaining small forest patches, often considered of low conservation value, was highlighted. These act as essential ‘stepping stones’ between forest patches, allowing species to traverse a landscape mosaic. The need for conservation measures not to disregard the importance of these small forest patches is emphasised, as they are vital assets to maintain species richness in landscape mosaics with forest patches.