The Importance of Forest-Nonforest Transition Zones for Avian Conservation in a Vegetation Disturbance Gradient in the Northern Neotropics

Abstract

Tropical landscape connectivity and matrix quality near large stands of primary forest are important factors that dictate biodiversity trends in communities. Suitable matrix management surrounding primary forest may help conserve biodiversity, but areas with poor matrix management need attention to determine their long-term viability to support native levels of biodiversity. We examined variations in species and functional diversity and community composition using point-count surveys placed in preserved (PRES), transition (TRA), and disturbed (DIS) areas according to percent land cover of forest and cattle pasture along a human disturbance gradient in the northern Neotropics during an 8 month period from 2019–2020. We expected the gradient of human disturbance to drive species diversity loss of forest specialists from PRES to DIS, resulting in changes to functional diversity and community composition. We detected 228 species overall, with 163 in PRES (40 unique species), 159 in TRA (9 unique species), and 152 in DIS (20 unique species). TRA supported an avian community with shared aspects of PRES and DIS, leading to the highest functional, Shannon (85.8 estimated species), and Simpson (57.9 estimated species) diversity. Higher diversity of open-area specialists in TRA and DIS has led to shifts in functional traits and different species and functional community compositions relative to PRES. Land management in Neotropical human-modified landscapes must focus on increasing habitat quality in remnant forest fragments in the vicinity of large stands of primary forest to prevent species and ecosystem service loss from preserved areas and the distancing of local community compositions.