Abandoned fields show higher insectivorous Bat species and functional diversity than forest fragments in a communal land area of the Eastern Cape, South Africa

Abstract Deagrarianisation is a global phenomenon with high potential for both carbon sequestration and biodiversity conservation. Work on this topic has focused on plant succession and associated plant diversity, but few studies have considered faunal communities, particularly in Africa. We used passive acoustic monitoring to record insectivorous bat communities within forest fragments and former fields under communal land tenure in the Transkei region (Eastern Cape Province) of South Africa. Insectivorous bat diversity in fields, abandoned in the 1960s to 1980s, resembling late stages of succession, were compared to fragments of Transkei Coastal Scarp Forest embedded within the landscape. We found that former fields hosted 14 species from 11 genera, comprising greater species richness, activity, Shannon-Weiner diversity, and functional diversity, irrespective of age, compared to forest fragments, which hosted nine species from seven genera. Furthermore, former fields exhibited comparable species richness to, and higher functional diversity than, three large neighbouring intact Transkei Scarp forests. Interestingly, the time since cultivation had ceased (35—64 years ago) had no significant effect on species and functional diversity. Former fields exhibited extensive invasion by Lantana camara (an alien shrub), and the indigenous pioneer tree Vachellia karoo , but nonetheless these landscapes have conservation value as they are diverse in both terms of insectivorous bat species and function. Mechanisms to enhance both biodiversity conservation; and the utility of the land for impoverished local communities, should be considered for former fields in tandem with forest patches, which remain important for bat roosting and foraging ecology, especially for specialist species.