Simulating the potential effects of cocoa-related deforestation on landscape connectivity in a West African biodiversity hotspot

In recent decades, the expansion of cocoa cultivation has been responsible for a substantial fraction of deforestation in the tropics. In the West African Guinean biodiversity hotspot the country of Ghana has been considerably affected. As the second largest cocoa producer in the world, the country has recently experienced a rapid increase in cocoa-related deforestation associated with a biodiversity decline, especially in terms of mammals. However, little is known about the landscape-scale consequences of deforestation for a range of biological parameters. Using the graph-based Probability of Connectivity (PC) metric, we explored how cocoa-related deforestation over the last two decades affected the network connectivity for mammals in the cocoa-dominated Juabeso-Bia landscape in Ghana. By classifying mammals based on their dispersal abilities and habitat preference, we were able to assess which species might have suffered the most from cocoa expansion. We found that cocoa-related deforestation, and more specifically conversion to monoculture plantations, did not simply result in habitat loss but also in a substantial decline in connectivity. The agricultural matrix's habitat loss between protected areas confines poor dispersers within fragmented forests and diminishes the suitable forest patches essential for the connectivity of proficient dispersers. Overall, our results suggest that connectivity mediated by cocoa agroforestry might help maintain landscape connectivity for mammals in a tropical landscape mosaic with scattered forest fragments, but this is subject to further validation. Jointly evaluating habitat quality and connectivity at landscape scale, as done in this paper, is important because it can help to judge the benefits of land sparing or sharing strategies for conservation.