Functional traits of avian species of an Afrotropical forest

Aim: Although land-use change is a leading cause of biodiversity loss
worldwide, there is scant information on the extent to which it has
affected the structure and composition of bird communities in the
Afrotropical region. This study aimed to quantify the effects of habitat
transformation on taxonomic, functional, and phylogenetic diversity in
Afrotropical bird communities. Location: Nyungwe landscape, a montane
rainforest with adjoining farmland in south-west Rwanda.
Methods: Data on bird occurrence, abundance, and functional
traits were collected in 2017/18 using point-counts. We also collected
data on habitat and morphological traits for all bird species recorded. We
quantified bird diversity using a range of metrics, including the Inverse
Simpson index, functional dispersion and the standardized effect size of
mean nearest taxon distance. Results: In comparison to primary
forest areas, even low levels of land-use change altered species
composition, and reduced species diversity. Although overall functional
and phylogenetic diversity were similar across land-use types, we found a
significant contraction of trophic and locomotory trait structures of bird
communities in restored areas and cultivated areas, respectively. Soil
moisture, elevation, and lower vegetation height were major factors
influencing taxonomic, functional and phylogenetic dimensions of bird
communities, although their effects varied across these dimensions. Main
conclusions: The sensitivity of forest species to minor habitat
disturbance emphasises the value of conserving primary vegetation.
Long-term conservation of bird communities in Afromontane ecosystems
requires halting wide-scale destruction of primary forest, promoting
vegetation heterogeneity in the ecological restoration of degraded
habitats, and adopting wildlife-friendly agricultural practices. Our
results suggest that monitoring and conservation in these landscapes can
be refined using taxonomic, functional and phylogenetic diversity metrics
to provide complementary information about the current and likely future
impacts of land-use change.