The influence of forest characteristics on avian species richness and functional diversity in Southern Mistbelt Forests of South Africa

Avian species functional diversity and habitat use: The role of forest structural attributes and tree diversity in the Midlands Mistbelt Forests of KwaZulu-Natal, South Africa

Forest transformation has major impacts on biodiversity and ecosystem functioning. Identifying the influence of forest habitat structure and composition on avian functional communities is important for conserving and managing forest systems. This study investigated the effect of forest structure and composition characteristics on bird species community structure, habitat use and functional diversity in 14 Mistbelt Forest patches of the Midlands of KwaZulu-Natal in South Africa. We surveyed bird communities using point counts. We quantified bird functional diversity for each forest patch using three diversity indices: functional richness, functional evenness and functional divergence. We further assessed species-specific responses by focussing on three avian forest specialists, orange ground-thrush Geokichla gurneyi, forest canary Crithagra scotops and Cape parrot Poicephalus robustus. We found that bird community and forest-specialist species responses to forest structure and tree species diversity differed. Also, forest structural complexity, canopy cover and tree species richness were the main forest characteristics better at explaining microhabitat influence on bird functional diversity. Forest patches with relatively high structural complexity and tree species richness had higher functional richness. Different structural characteristics influenced habitat use by the three forest specialists. Tree species diversity influenced C. scotops and G. gurneyi positively, while P. robustus responded negatively to forest patches with high tree species richness. Our study showed that site-scale forest structure and composition characteristics are important for bird species richness and functional richness. Forest patches with high tree species diversity and structural complexity should be maintained to conserve forest specialists, bird species richness and functional richness.

Variations in Avian Species and Functional Diversity in Different Habitat Types in a Vulnerable Savannah Ecosystem in Ghana

Most research on avian functional diversity in the tropics is focused on forest and agroecosystems, leaving a gap in knowledge about the effects of habitat types on functional diversity in savannah landscapes. Savanna ecosystems are fragile and are under threat of anthropogenic destruction, particularly in developing Sub-Saharan Africa and could be eliminated in the face of the ever-increasing human population exacerbated by the changing climate. This study investigated the influence of the three major habitat types (grassland, riparian forest, woodland) on bird species and functional diversity in the Mole National Park (MNP) in Ghana. We used the line transect method to survey birds along 39 transects, each 1 km in length, and collected data on environmental variables along the same transects. Data from these surveys was used to estimate species and functional diversity indicators. We found significant variations in species and functional diversity measures between the three habitat types in the MNP. These variations were significantly influenced by species abundance and environmental covariates. Diversity measures were particularly higher in the riparian forest habitats compared to the woodland and grassland, with the latter being the least diverse habitat both functionally and species wise. The results of this study suggest that the avifauna assemblages in MNP are largely influenced by the riparian forest and are important for ecosystem function and stability. We recommend management efforts to intensify the protection of such vital habitats of the Mole National Park from illegal human activities, especially the rising removal and export of rosewoods (Dalbergia nigra) around the park. Further research on the avian community composition and structure in the MNP is recommended.