Latitudinal effects of anthropogenic factors driving raptor species richness across the American continent

Abstract

AbstractAimGeographic gradients in species richness have been traditionally attributed to variation in environmental conditions. However, untangling the importance of human activities in explaining spatial patterns in raptor species richness, still remains a challenge. We evaluated the relative importance of how human impacts and ecogeographical conditions shape the latitudinal patterns of resident (n = 140) and migratory (n = 35) raptor species richness in the American continent, and analysed whether these factors differ between the Nearctic and the Neotropical regions.LocationAmerican Continent.TaxonRaptor species.MethodsWe processed BirdLife distributional data for 175 raptor species distributed in America, and a set of three ecogeographical and three human impact variables at a spatial resolution of 96.5 × 96.5 km. We applied simple, multiple, simultaneous auto‐regressive models and partial regression analyses to explore the associations between ecogeographical conditions and human impacts on raptor richness.ResultsAt the continental scale and the Neotropical region, global forest structure is the main driver of richness patterns for all raptors combined, and for resident and migratory species alone. In the Nearctic region, human accessibility was the best explanatory variable to understand the spatial patterns of richness regardless of the raptor group analysed.Main conclusionsEnvironmental features play a leading role in determining raptor species richness. However, the independent contribution of human activities emerges as an important factor in explaining richness patterns of migratory species at the continental scale and within the Neotropical region, whereas humans become particularly important in the Nearctic region for all raptors, residents and migratory species. We show for the first time how human‐related factors influence raptor species richness.