High sensitivity of tropical forest birds to deforestation at lower altitudes

Mills, Simon C. and Socolar, Jacob B. and Edwards, Felicity A. and Parra, Edicson and Martínez‐Revelo, Diego E. and Quintero, Jose Manuel Ochoa and Haugaasen, Torbjørn and Freckleton, Robert P. and Barlow, Jos and Edwards, David P. (2023) High sensitivity of tropical forest birds to deforestation at lower altitudes. Ecology, 104 (1). ISSN 0012-9658

Abstract

Habitat conversion is a major driver of tropical biodiversity loss, but its effects are poorly understood in montane environments. While community-level responses to habitat loss display strong elevational dependencies, it is unclear whether these arise via elevational turnover in community composition and interspecific differences in sensitivity, or elevational variation in environmental conditions and proximity to thermal thresholds. Here, we assess the relative importance of inter and intraspecific variation across the elevational gradient by quantifying how 243 forest-dependent bird species vary in sensitivity to landscape-scale forest loss across a 3000 m elevational gradient in the Colombian Andes. We find that species that live at lower elevations are strongly affected by loss of forest in the nearby landscape, while those at higher elevations appear relatively unperturbed, an effect that is independent of phylogeny. Conversely, we find limited evidence of intraspecific elevational gradients in sensitivity, with populations displaying similar sensitivities to forest loss, regardless of where they exist in a species’ elevational range. Gradients in biodiversity response to habitat loss thus appear to arise via interspecific gradients in sensitivity rather than proximity to climatically limiting conditions.