McDonald Peter J, Jobson Peter, Köhler Frank, Nano Catherine E M, Oliver Paul M
Secretariat of the Pacific Regional Environment Program Apia Samoa.
Department of Environment and Natural Resources Northern Territory Herbarium Alice Springs NT Australia.
Ecol Evol. 2021 Mar 15;11(9):4366-4378. doi: 10.1002/ece3.7333. eCollection 2021 May.
Mountain regions are centers of biodiversity endemism at a global scale but the role of arid-zone mountain ranges in shaping biodiversity patterns is poorly understood. Focusing on three guilds of taxa from a desert upland refugium in Australia, we sought to determine: (a) the relative extent to which climate, terrain or geological substrate predict endemism, and (b) whether patterns of endemism are complimentary across broad taxonomic guilds. We mapped regional endemism for plants, land snails, and vertebrates using combined Species Distribution Models (SDMs) for all endemic taxa ( = 82). We then modelled predictors of endemism using Generalised Additive Models (GAMs) and geology, terrain, and climate variables. We tested for the presence of inter- and intraguild hotspots of endemism. Many individual plant and land snail taxa were tightly linked with geology, corresponding to small distributions. Conversely, most vertebrate taxa were not constrained to specific geological substrates and occurred over larger areas. However, across all three guilds climate was the strongest predictor of regional endemism, particularly for plants wherein discrete hotspots of endemism were buffered from extreme summer temperatures. Land snail and vertebrate endemism peaked in areas with highest precipitation in the driest times of the year. Hotspots of endemism within each guild poorly predicted endemism in other guilds. We found an overarching signal that climatic gradients play a dominant role in the persistence of endemic taxa in an arid-zone mountain range system. An association with higher rainfall and cooler temperatures indicates that continuing trends toward hotter and drier climates may lead to range contractions in this, and potentially other, arid-zone mountain biotas. Contrasting patterns of endemism across guilds highlight the need to couple comprehensive regional planning for the protection of climate refugia, with targeted management of more localized and habitat specialist taxa.
山区是全球生物多样性特有性的中心，但干旱地区山脉在塑造生物多样性模式中的作用却鲜为人知。以澳大利亚一个沙漠高地避难所的三类生物类群为研究对象，我们试图确定：（a）气候、地形或地质基质在预测特有性方面的相对程度，以及（b）特有性模式在广泛的生物分类类群中是否互补。我们使用所有特有分类单元（n = 82）的组合物种分布模型（SDMs）绘制了植物、陆地蜗牛和脊椎动物的区域特有性图谱。然后，我们使用广义相加模型（GAMs）以及地质、地形和气候变量对特有性的预测因子进行建模。我们测试了类群间和类群内特有性热点的存在情况。许多单个植物和陆地蜗牛分类单元与地质紧密相连，分布范围较小。相反，大多数脊椎动物分类单元不受特定地质基质的限制，分布范围更广。然而，在所有这三类生物类群中，气候是区域特有性的最强预测因子，尤其是对于植物而言，其特有性的离散热点区域免受夏季极端温度的影响。陆地蜗牛和脊椎动物的特有性在一年中最干燥时期降水量最高的地区达到峰值。每个类群内的特有性热点对其他类群的特有性预测效果不佳。我们发现一个总体信号，即气候梯度在干旱地区山脉系统中特有分类单元的存续中起主导作用。与较高降雨量和较低温度的关联表明，气候持续变热和变干的趋势可能导致该干旱地区山脉生物群以及其他潜在生物群的分布范围缩小。不同类群间特有性模式的差异凸显了将保护气候避难所的全面区域规划与对更本地化和栖息地特化分类单元的针对性管理相结合的必要性。
