Data from: Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird

The Eastern Afromontane cloud forests occur as geographically distinct mountain exclaves. The conditions of these forests range from large to small and from fairly intact to strongly degraded. For this study, we sampled individuals of the forest bird species, the Montane White-eye Zosterops poliogaster from 16 sites and four mountain archipelagos. We analysed 12 polymorphic microsatellites and three phenotypic traits, and calculated Species Distribution Models (SDMs) to project past distributions and predict potential future range shifts under a scenario of climate warming. We found well-supported genetic and morphologic clusters corresponding to the mountain ranges where populations were sampled, with 43% of all alleles being restricted to single mountains. Our data suggest that large-scale and long-term geographic isolation on mountain islands caused genetically and morphologically distinct population clusters in Z. poliogaster. However, major genetic and biometric splits were not correlated to the geographic distances among populations. This heterogeneous pattern can be explained by past climatic shifts, as highlighted by our SDM projections. Anthropogenically fragmented populations showed lower genetic diversity and a lower mean body mass, possibly in response to suboptimal habitat conditions. On the basis of these findings and the results from our SDM analysis we predict further loss of genotypic and phenotypic uniqueness in the wake of climate change, due to the contraction of the species’ climatic niche and subsequent decline in population size.东非山地云雾林呈地理上独立的山地飞地格局分布。该类森林的分布规模不等，且受干扰程度差异显著，从近乎原始完好到严重退化均有分布。本研究以森林鸟类山地绣眼鸟（Zosterops poliogaster）为研究对象，从4个山地群岛样区的16个采样点采集了其个体样本。我们对12个多态性微卫星位点与3个表型性状进行了分析，并构建了物种分布模型（Species Distribution Models, SDMs），以推演该物种的历史分布范围，并预测气候变暖情景下其未来潜在的分布区变化。研究结果显示，存在得到充分支持的遗传与形态聚类群，且这些聚类群与采样种群所在的山地范围高度对应；所有等位基因中有43%仅局限于单个山地。本研究数据表明，山地孤岛所经历的大规模长期地理隔离，造就了山地绣眼鸟（Zosterops poliogaster）遗传与形态上均存在显著差异的种群聚类群。然而，主要的遗传与形态测量分化与种群间的地理距离并无关联。正如我们的物种分布模型推演结果所证实的，这种异质性分布格局可由过往的气候变迁得到解释。受人类活动干扰而片段化的种群，其遗传多样性与平均体重均更低，这可能是其对次优栖息地条件的响应。基于上述研究结果与物种分布模型分析结论，我们预测：随着气候变迁引发该物种气候生态位收缩，进而导致种群规模下降，其基因型与表型的独特性将进一步丧失。