A Systematic Review of Global Drivers of Ant Elevational Diversity

Ant diversity shows a variety of patterns across elevational gradients, though the patterns and drivers have not been evaluated comprehensively. In this systematic review and reanalysis, we use published data on ant elevational diversity to detail the observed patterns and to test the predictions and interactions of four major diversity hypotheses: thermal energy, the mid-domain effect, area, and the elevational climate model. Of sixty-seven published datasets from the literature, only those with standardized, comprehensive sampling were used. Datasets included both local and regional ant diversity and spanned 80° in latitude across six biogeographical provinces. We used a combination of simulations, linear regressions, and non-parametric statistics to test multiple quantitative predictions of each hypothesis. We used an environmentally and geometrically constrained model as well as multiple regression to test their interactions. Ant diversity showed three distinct patterns across elevations: most common were hump-shaped mid-elevation peaks in diversity, followed by low-elevation plateaus and monotonic decreases in the number of ant species. The elevational climate model, which proposes that temperature and precipitation jointly drive diversity, and area were partially supported as independent drivers. Thermal energy and the mid-domain effect were not supported as primary drivers of ant diversity globally. The interaction models supported the influence of multiple drivers, though not a consistent set. In contrast to many vertebrate taxa, global ant elevational diversity patterns appear more complex, with the best environmental model contingent on precipitation levels. Differences in ecology and natural history among taxa may be crucial to the processes influencing broad-scale diversity patterns.

蚂蚁多样性沿海拔梯度呈现多种分布模式，不过相关模式及其驱动因子尚未得到全面评估。在本系统综述与再分析研究中，我们利用已发表的蚂蚁海拔多样性数据，详细阐明已观测到的分布模式，并检验四大主流多样性假说的预测结果及其交互作用：热能假说、中域效应（mid-domain effect）、面积假说以及海拔气候模型。在文献中收录的67份已发表数据集里，仅采用了经过标准化、全面采样的数据集。这些数据集涵盖了局域和区域尺度的蚂蚁多样性，且横跨六大生物地理分区，纬度跨度达80°。我们结合模拟分析、线性回归与非参数统计方法，检验各假说的多项定量预测；同时采用环境与几何约束模型以及多元回归方法，检验它们的交互作用。蚂蚁多样性沿海拔梯度呈现三种显著模式：最常见的是多样性在中海拔处呈驼峰状峰值，其次是低海拔平台区，以及蚂蚁物种数随海拔单调递减。提出温度与降水共同驱动多样性的海拔气候模型，以及面积假说，作为独立驱动因子得到了部分支持。热能假说与中域效应则未被支持为全球尺度下蚂蚁多样性的主要驱动因子。交互作用模型证实了多驱动因子的影响，但未发现一致的驱动因子组合。与诸多脊椎动物类群不同，全球尺度下的蚂蚁海拔多样性模式更为复杂，最优环境模型取决于降水水平。类群间生态学与自然历史的差异，可能是影响大尺度多样性模式的关键因素。