- University: AgroParisTech
- Place of defence: Montpellier
- Hosting institution(s): Max Planck Institute of Animal Behavior & Eidgenössische Technische Hochschule (ETH) Zurich
Abstract
Natural forest regeneration is essential for carbon sequestration, biodiversity conservation, and sustaining local livelihoods. Frugivorous birds facilitate this process by dispersing seeds into open areas, yet their movements and effectiveness can be constrained in fragmented landscapes. The cascading effects of fragmentation on frugivore communities, their seed-dispersal–related functional traits, and the resulting consequences for seed-rain composition and regenerative potential in open areas remain poorly understood. In this study, I analysed bird-mediated seed rain across landscapes with 20%, 40%, and 60% forest cover and along distance gradients from forest edges. Genetic metabarcoding allowed identification of both the bird and plant species in each defecation event, enabling assessment of how species composition and functional traits shifted across forest covers and distance to the forest edge. Landscapes with 60% forest cover supported higher frugivore diversity and seed-rain richness, although only a subset of species acted as effective dispersers in open areas. Species richness in both birds and plants remained stable with distance, while community composition became increasingly dissimilar. Functional turnover in bird traits emerged only in the most fragmented landscape (20%), yet this shift did not translate into differences in seed-rain functional traits. These findings highlight the dominant role of generalist seed dispersers in open areas and emphasize the importance of tailoring restoration strategies to landscape context, particularly by enhancing connectivity in highly fragmented areas.
