Promoting functional connectivity of anthropogenically-fragmented forest patches for multiple taxa across a critically endangered biome

Abstract

Abstract Connectivity, the degree to which the landscape structure allows movement between resource and habitat patches, is vital for facilitating a wide range of ecological processes across transformed and anthropogenic landscapes. Connectivity is critical for dispersal of individuals from natal sites, colonisation of patches across a landscape by populations, the structuring of populations, and their persistence across metacommunities. Here, we present a replicable methodology for conservation and land-management practitioners to promote maximal functional connectivity for multiple taxa across a mixed land-use mosaic containing natural habitat patches. We used the maximal functional diversity present in three key taxa (trees, birds, and mammals) responsible for the persistence of forests and the provisioning of ecosystem function and services, in a mosaic landscape of natural, agricultural, and urban land-use practices to map probabilistic connectivity corridors. We used a hybrid of Circuit Theory, least-cost resistance pathways and pinch-points based on the traits and ecological parameters of a surrogate taxon to map functional connectivity across an anthropogenically-fragmented and critically endangered forest biome, the Indian Ocean Coastal Belt Forest of South Africa. By using functional diversity measures, rather than taxonomic species richness, we ensured that maximal ecosystem services were safeguarded, concurrently achieving high-priority conservation goals of protecting specialist, endangered, and range-restricted species and traits that may otherwise be lost through high turnover of generalists at the expense of specialist species. Mapping circuit/least-cost corridors and critical pinch-points in remnant natural, yet unprotected forested patches, highlighted priority habitat to be conserved for promoting maximal functional connectivity, cognisant of the restricted budgets available for conservation planning and landscape-level protection. Our approach simultaneously protects ecosystem services, threatened specialist species and traits, and range-restricted and endangered habitats, linking current Protected Areas while prioritising landscape features of connectivity importance to be conserved for land-management practitioners with limited budgets.