Rapid assessment of post-dispersal seed removal in an agricultural landscape of semi-arid West Africa

Post-dispersal seed removal is crucial for maintaining plant recruitment by influencing secondary dispersal and the mortality of seeds. However, data on seed removal in the northern savanna of Ghana is scarce. In this study, we applied a rapid assessment method to examine the effect of three habitat types (conventional farmland, agroforestry parkland, and woodland) and two seed species (Leucaena leucocephala and Faidherbia albida) on seed removal by invertebrates and vertebrates in an agricultural landscape using selective exclosures in Nyankpala, a town located in the northern savanna of Ghana. The exclosures, closed and open, were designed to impose restrictions that allow either invertebrates or both invertebrates and vertebrates access to seeds. Using a generalized linear mixed modelling approach, we showed that habitat type and seed species significantly influenced the rate of seed removal, with the woodland habitat and F. albida seeds recording the highest removal rates. Our results suggest that invertebrates often dominated seed removal events compared to vertebrates, possibly due to differences in allometry and morphological traits and their effect on seed preference. This study adds to the growing evidence that savanna habitats and fauna play a critical role in maintaining plant population dynamics through seed predation and dispersal events.