Data from: Forest-associated understorey birds persist in agroforestry orchards within tropical rubber and oil palm landscapes

Tropical agricultural landscapes can support biodiversity, including
forest spill-over species, shaped by habitat factors operating at multiple
scales. Understanding these factors is crucial for conserving biodiversity
and maintaining ecosystem services. Using mist-netting data, this study
examined how land-cover changes influence understorey birds and identified
key factors at stand- and landscape-levels, along with a site-specific
feature, affecting bird assemblages in agroforestry orchards, rubber tree,
and oil palm plantations in Peninsular Malaysia. We captured 39 species
over 9,900 netting hours, with forest-associated species comprising 33% of
the total. Agricultural type emerged as primary driver of bird diversity,
with agroforestry orchards supporting greater species richness and
abundance. Canopy cover negatively influenced species richness, total
abundance, and the occurrence of carnivorous/insectivorous and
granivorous/frugivorous birds. Understorey vegetation height positively
impacted bird total abundance. Elevation negatively influenced bird
abundance and the occurrence of omnivores but positively affected
forest-associated species. Distance to forest was negatively correlated
with bird abundance and the occurrence of omnivorous birds. Our findings
highlight agroforestry orchards as avian refuges and biological corridors
that enhance landscape connectivity and ecosystem functioning in
agricultural areas. Specifically, in our region, dense canopy cover in
monoculture plantations reduced bird richness and abundance, likely due to
reduced sunlight suppressing understorey vegetation and limiting resource
availability. Conversely, agroforestry orchards with more open canopy and
structurally complex vegetation supported a greater diversity of feeding
guilds, including certain forest-associated species. These results
underscore the importance of managing tropical farmland by maintaining
understorey growth, increasing canopy heterogeneity, and reducing
isolation from forest remnants.