Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield, UK.
Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway.
Ecology. 2023 Jan;104(1):e3867. doi: 10.1002/ecy.3867. Epub 2022 Nov 14.
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.
生境转换是热带生物多样性丧失的主要驱动因素，但在高山环境中，其影响还知之甚少。虽然社区层面的对生境丧失的响应表现出强烈的海拔依赖性，但尚不清楚这些依赖性是通过群落组成的海拔更替、种间敏感性差异还是环境条件的海拔变化以及与热阈值的接近程度产生的。在这里，我们通过量化 243 种依赖森林的鸟类物种在哥伦比亚安第斯山脉 3000 米海拔梯度上对景观尺度森林丧失的敏感性如何变化，来评估种间和种内变异在海拔梯度上的相对重要性。我们发现，生活在较低海拔地区的物种受到附近景观中森林丧失的强烈影响，而生活在较高海拔地区的物种则相对不受干扰，这种效应与系统发育无关。相反，我们发现种内对敏感性的海拔梯度的证据有限，无论它们在物种海拔范围内的哪个位置，种群对森林丧失的敏感性都相似。因此，生物多样性对生境丧失的响应梯度似乎是通过敏感性的种间梯度而不是对气候限制条件的接近程度产生的。
