Evaluating landscape connectivity methods for wildlife corridors in the Greater Limpopo Transfrontier Conservation Area

Abstract

The importance of safeguarding landscape connectivity to mitigate against biodiversity loss, climate change, habitat fragmentation and increasing human disturbance is globally recognized. Transfrontier Conservation Areas (TFCAs) in particular hold much promise in providing ecological connectivity through the establishment of transboundary ecological networks of protected areas connected by ecological corridors. Connectivity modelling involves numerous decisions which impact connectivity outcomes and consequently the systematic conservation plan (SCP). However, there is insufficient research on how different decisions on parameterisation to code human modification (or barriers), choice of land cover datasets, extent and scale impact conservation planning outcomes. Given the technical and financial complexities associated with large scale connectivity planning, an inexpensive, first step is to evaluate the structural connectivity of the region by using a species-agnostic approach, allowing for the delineation of natural or ‘wild’ areas that could function as ecological corridors. Two commonly used resistance-based connectivity models, namely least-cost path (Linkage Mapper) and circuit theory (Julia implementation), are compared here, including their sensitivity to parameterisation, using a species-agnostic approach based on naturalness to model wildlife corridors between protected areas within the GLTFCA. The connectivity map outputs followed a similar pattern for both methods. The stability of corridor locations was the most sensitive to the range of resistance values at coarser spatial resolutions. Additionally, the outputs were influenced by linear barriers more than the human-modified landcover patch elements, with the choice of land cover dataset not having a large impact. This study reaffirms the complementary nature of connectivity methods and their different assumptions, highlights the importance of parameter selection, and incorporation of uncertainty and sensitivity analysis within connectivity modelling and systematic conservation planning frameworks.