Raptor breeding sites as a surrogate for conserving high avian taxonomic richness and functional diversity in urban ecosystems

Abstract

Preserving biodiversity and ecosystem functions in rapidly increasing urban areas has become a focal issue of conservation science. With limited budgets and human resources, a potentially efficient conservation strategy is to prioritize important areas in urban ecosystems, based on raptor habitats. Here, northern goshawk (Accipiter gentilis) breeding sites in urban Kanagawa, Japan were used to explore the effectiveness of raptor habitats as conservation surrogates for biodiversity and ecosystem function. The presence of birds was recorded within 500 m of 37 goshawk breeding sites through point counts in the breeding season of 2019. Species richness and dendrogram-based functional diversity (FD) were then determined as measures of biodiversity and ecosystem function, respectively. As controls, 50 sites with landscape compositions similar to goshawk breeding sites were also evaluated. The analysis involved two generalized linear models using species richness and FD as response variables and the presence/absence of goshawk breeding sites as covariates. Goshawk breeding sites had a significant positive effect on species richness and FD, explaining most of their variance (species richness: 63.0%, FD: 56.9%). In conclusion, this study confirmed that goshawk breeding sites that maintain high urban biodiversity and ecosystem function can be used to prioritize and preserve important areas for conservation.