First survey of the fungi from the bakwena cave in South Africa sugg ests low human disturbance

Currently there are no studies on the microbial karst niche in South Africa. Most of the studies on these environments focus on archaeology and animals that occur in caves. However, there are several caves that are threatened by urban development of the surrounding areas. The Bakwena Cave is such a threatened cave with extensive urban development of the surrounding grassland biome it is located in. The cave is located in dolomite and the entrance is a sinkhole. This cave serves as a permanent roost for a large population of Natal clinging bats Miniopterus natalensis. The ecosystem of the cave is driven by the deposition of guano by the bats, as there is no deep penetration of plant debris from the outside. To identify the fungal component of the microbial ecosystem, we sampled guano, soil, and sediment from various areas within the cave over a period of one year. All isolations were performed on low-nutrient medium to restrict the colony growth and to ensure that all culturable fungi were obtained. These isolates were barcoded using the ITS1 gene region to identify them and to establish a baseline of fungi occurring in South African caves. The majority of isolates associated were Aspergillus and Penicillium species identified in previous studies from cave environments. Some opportunistic pathogens were identified that could have an impact as more people visit the cave due to its close proximity to housing developments. However, currently the cave fits a model that indicates it has a low level of human disturbance. Our study is the first on the cave fungal component in South Africa and provides a baseline that can advise developers and environmental impact assessments on fungal species found in caves.