Colwell Robert K, Gotelli Nicholas J, Ashton Louise A, Beck Jan, Brehm Gunnar, Fayle Tom M, Fiedler Konrad, Forister Matthew L, Kessler Michael, Kitching Roger L, Klimes Petr, Kluge Jürgen, Longino John T, Maunsell Sarah C, McCain Christy M, Moses Jimmy, Noben Sarah, Sam Katerina, Sam Legi, Shapiro Arthur M, Wang Xiangping, Novotny Vojtech
Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.
Departmento de Ecologia, Universidade Federal de Goiás, CP 131, Goiânia, GO, 74.001-970, Brasil.
Ecol Lett. 2016 Sep;19(9):1009-22. doi: 10.1111/ele.12640. Epub 2016 Jun 30.
We introduce a novel framework for conceptualising, quantifying and unifying discordant patterns of species richness along geographical gradients. While not itself explicitly mechanistic, this approach offers a path towards understanding mechanisms. In this study, we focused on the diverse patterns of species richness on mountainsides. We conjectured that elevational range midpoints of species may be drawn towards a single midpoint attractor - a unimodal gradient of environmental favourability. The midpoint attractor interacts with geometric constraints imposed by sea level and the mountaintop to produce taxon-specific patterns of species richness. We developed a Bayesian simulation model to estimate the location and strength of the midpoint attractor from species occurrence data sampled along mountainsides. We also constructed midpoint predictor models to test whether environmental variables could directly account for the observed patterns of species range midpoints. We challenged these models with 16 elevational data sets, comprising 4500 species of insects, vertebrates and plants. The midpoint predictor models generally failed to predict the pattern of species midpoints. In contrast, the midpoint attractor model closely reproduced empirical spatial patterns of species richness and range midpoints. Gradients of environmental favourability, subject to geometric constraints, may parsimoniously account for elevational and other patterns of species richness.
我们引入了一个全新的框架，用于概念化、量化和统一物种丰富度沿地理梯度的不一致模式。虽然该方法本身并非明确的机制性方法，但它为理解机制提供了一条途径。在本研究中，我们聚焦于山坡上物种丰富度的多样模式。我们推测物种的海拔范围中点可能被吸引至一个单一的中点吸引子——一个环境适宜性的单峰梯度。中点吸引子与海平面和山顶所施加的几何约束相互作用，从而产生特定分类群的物种丰富度模式。我们开发了一个贝叶斯模拟模型，以根据沿山坡采样的物种出现数据来估计中点吸引子的位置和强度。我们还构建了中点预测模型，以检验环境变量是否能直接解释观察到的物种范围中点模式。我们用16个海拔数据集对这些模型进行了验证，这些数据集包含4500种昆虫、脊椎动物和植物。中点预测模型通常无法预测物种中点的模式。相比之下，中点吸引子模型紧密再现了物种丰富度和范围中点的经验空间模式。受几何约束的环境适宜性梯度可能简洁地解释物种丰富度的海拔及其他模式。
