Data from: Climate and local abundance in freshwater fishes

Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa.

探明调控物种分布范围内不同种群间个体数量差异的影响因子，是生态学的核心研究目标之一。学界普遍提出的一项预测——即丰度中心假说（abundant-centre hypothesis）——认为物种分布范围内的种群丰度在分布区中心附近达到最高。然而，由于该假说最初仅聚焦于种群的地理区位，其几乎未能揭示调控局域丰度的环境因子。尽管针对陆生类群，学界已开展了与环境条件相关的种群丰度全分布区差异研究，但针对淡水类群，其分布区内气候与局域丰度之间的关联仍未得到充分阐释。本研究基于地理信息系统（GIS）获取的气温与降水数据，分析了19种北美淡水鱼类的气候条件与其局域丰度的全分布区差异之间的关联。结果显示，气候因子可解释18个物种的种群间局域丰度差异的一部分。此外，不同物种间气候条件与局域丰度的关联模式存在差异，这符合不同谱系在地理空间中分化适配环境的预期。局域生境质量对物种存续的影响已有大量研究佐证；然而本研究结果表明，即便在水生类群中，气候因子在调控物种全分布区的种群规模方面同样发挥着重要作用。