BIRD DIVERSITY ACROSS AN ANDEAN CITY: THE LIMITATION OF SPECIES RICHNESS VALUES AND WATERSHED SCALES

Abstract

Evaluating several biodiversity descriptors and considering several spatial scales might elucidate conservation issues and improve biodiversity monitoring in urban environments. We estimated species richness (order q = 0), Shannon diversity (order q = 1), and Simpson diversity (order q = 2) based on Hill numbers and performed cluster analysis and non-metric multidimensional scaling (NMDS) to compare seven urban micro-watersheds and a peri-urban site across a northern Andean city (Medellín, Colombia). We found 113 diurnal resident bird species: 50 (44 %) exclusively within urban sites, 21 (19 %) exclusively in the periurban site, and 42 (37 %) shared species. Some urban watersheds had similar bird species richness to the periurban site, but Shannon and Simpson diversities were always lower, showing decrease in local bird diversity when abundances were considered. Bird species composition differed between urban watersheds and the periurban site, with all urban watersheds grouped altogether by cluster and NMDS analysis, and the periurban site forming its own group. This suggests homogenization of bird species composition due to the species turnover decreasing across urban areas, with endemic, near endemic and rare species restricted to periurban areas where native forest remnants persist. Several scales of biodiversity and analysis at more local scales are needed to better understand biodiversity patterns across Andean cities and to design urban planning strategies that prevent biodiversity loss.