Biodiversity patterns diverge along geographic temperature gradients

Models applying space-for-time substitution, including those projecting ecological responses to climate change, generally assume an elevational and latitudinal equivalence that is rarely tested. However, a mismatch may lead to different capacities for providing climatic refuge to dispersing species. We compiled community data on zooplankton, ectothermic animals that form the consumer basis of most aquatic food webs, from over 1,200 mountain lakes and ponds across western North America to assess biodiversity along geographic temperature gradients spanning nearly 3,750 metres of elevation and 30 degrees latitude. Species richness, phylogenetic relationships, and functional diversity all showed contrasting responses across gradients, with richness metrics plateauing at low elevations but exhibiting intermediate latitudinal maxima. The nonmonotonic/hump-shaped diversity trends with latitude emerged from geographic interactions, including weaker latitudinal relationships at higher elevations...

采用空间代时间替代法（space-for-time substitution）的模型（包括预测气候变化生态响应的模型）通常默认海拔与纬度具有等效性，但该假设极少得到实证检验。然而，假设不匹配可能会导致为扩散物种提供气候庇护的能力出现差异。我们从北美西部1200余个山地湖泊与池塘中收集了浮游动物（zooplankton）群落数据——这类变温动物（ectothermic animals）是多数水生食物网的消费者基础——以沿跨越近3750米海拔与30度纬度的地理温度梯度评估生物多样性。物种丰富度、系统发育关系与功能多样性在两类梯度上均呈现出截然不同的响应：丰富度指标在低海拔区域趋于平稳，但在纬度梯度上则表现出中间峰值。纬度梯度下的非单调/驼峰型多样性趋势源于地理交互效应，其中高海拔区域的纬度相关性显著减弱……