Biogeography and landscape predictors of species richness in Nicaraguan dry forest birds
| Authors: | Wayne J. Arendt, Marvin Torrez, Edgar Castañeda, María Elena Salgado García, Marlon Sotelo, Orlando Jarquín |
| Year: | 2026 |
| Type: | Scientific Journal |
| Station: | International Institute of Tropical Forestry |
| DOI: | https://doi.org/10.58843/ornneo.v37i1.1407 |
| Source: | Ornitología Neotropical |
Abstract
Knowledge of Nicaragua's Pacific slope seasonal tropical dry forest ecosystem and its avifauna remains limited, hindering effective conservation planning. To assess avian community composition and relative abundance, from 2009 to 2018 we conducted standardized monthly surveys in 147 point counts at 29 study sites along Nicaragua's Pacific slope. We also determined the influence of geographic, climatic, and landscape predictors on avian species richness and community similarity among sites. Overall, we documented 257 species at 29 study sites along the Pacific slope, including 17 species that were not previously reported, bringing the cumulative total known from the Pacific slope to 440 species, representing 57% of the country's avifauna. Species distributions exhibited strong geographic heterogeneity: Pacific-exclusive taxa predominated from Chinandega to Managua, whereas Caribbean-affiliated species peaked in Rivas. The geographic variable of elevation did not significantly influence overall species richness, but percent of forest-dependent species increased marginally with elevation, having highest densities in Rivas (70%) and Granada (17%). Landscape variables of tree cover and forest patch size were not associated with overall avian richness, but a larger forest patch size strongly predicted a higher percent of forest-dependent species, underscoring the importance of habitat contiguity. Biogeographic clustering further distinguished the northern and southern assemblages, with unique highland communities above 1000 m. These findings highlight the Pacific slope as a region of exceptional but uneven avian diversity, where the conservation of large, contiguous forest patches, particularly in montane zones, is critical for sustaining forest specialists, maintaining ecological connectivity, and safeguarding ecosystem services.