Bat species diversity at Rugezi Marsh, northern Rwanda, as a basis for wetland conservation

Abstract

East African marshlands are critical natural resources, but information on wildlife species richness and abundance is lacking. Rwanda is characterised by its hilly terrain, with marshes and other wetlands accounting for approximately 8% of the nation's area. Marshlands, which serve as roosting and foraging sites, are expected to harbour a greater diversity of bat species than adjacent open farms and eucalypt-dominated hills. A survey of bats was conducted at Rugezi Marsh, northern Rwanda, in 2023, across two distinct seasons, June to July and November to December. Roost searches, traditional capture methods, acoustic monitoring, and DNA barcoding were used to gather data. Twenty-two bat species across six families were recorded, including an undetermined Pipistrellus that may represent a new species based on molecular data and therefore warrants further examination. Remarkably, more than forty per cent of Rwanda’s bat biodiversity is found here; nonetheless, many species appear to be rare, such as the threatened Harrison's giant mastiff bat (Otomops harrisoni), which is designated as Vulnerable on the IUCN Red List. Strong grounds exist for the protection of this wetland because of the exceptionally high bat species richness, including one threatened species. The baseline data on bat biodiversity offer a unique opportunity for tracking changes with the potential restoration of this special wetland.