Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA.
Mol Ecol. 2010 Jun 1;19(12):2531-44. doi: 10.1111/j.1365-294X.2010.04676.x. Epub 2010 May 21.
Globally, montane tropical diversity is characterized by extraordinary local endemism that is not readily explained by current environmental variables indicating a strong imprint of history. Montane species often exist as isolated populations under current climatic conditions and may have remained isolated throughout recent climatic cycles, leading to substantial genetic and phenotypic divergence. Alternatively, populations may have become contiguous during colder climates resulting in less divergence. Here we compare responses to historical climate fluctuation in a montane specialist skink, Lampropholis robertsi, and its more broadly distributed congener, L. coggeri, both endemic to rainforests of northeast Australia. To do so, we combine spatial modelling of potential distributions under representative palaeoclimates, multi-locus phylogeography and analyses of phenotypic variation. Spatial modelling of L. robertsi predicts strong isolation among disjunct montane refugia during warm climates, but with potential for localized exchange during the most recent glacial period. In contrast, predicted stable areas are more widespread and connected in L. coggeri. Both species exhibit pronounced phylogeographic structuring for mitochondrial and nuclear genes, attesting to low dispersal and high persistence across multiple isolated regions. This is most prominent in L. robertsi, for which coalescent analyses indicate that most populations persisted in isolation throughout the climate cycles of the Pleistocene. Morphological divergence, principally in body size, is more evident among isolated populations of L. robertsi than L. coggeri. These results highlight the biodiversity value of isolated montane populations and support the general hypothesis that tropical montane regions harbour high levels of narrow-range taxa because of their resilience to past climate change.
从全球范围来看，山地热带地区的物种多样性具有显著的地方特有性，这很难用当前的环境变量来解释，表明历史的影响非常强烈。山地物种通常在当前气候条件下以孤立的种群形式存在，并且可能在最近的气候循环中一直保持隔离状态，导致大量的遗传和表型分化。或者，在较冷的气候条件下，种群可能会变得连续，从而减少分化。在这里，我们比较了澳大利亚东北部热带雨林特有种罗氏锦蛇（Lampropholis robertsi）及其分布范围更广的同种 Lampropholis coggeri 对历史气候变化的响应，这两种蛇都是山地专家。为此，我们结合了潜在分布的空间模型，代表古气候，多基因谱系地理和表型变异分析。罗氏锦蛇的空间模型预测，在温暖气候下，各山地避难所之间会出现强烈的隔离，但在最近的冰期期间，仍有可能进行局部交换。相比之下，预测的稳定区域在 L. coggeri 中分布更广泛且相互连接。两种物种的线粒体和核基因都表现出明显的系统地理结构，证明了在多个隔离地区具有较低的扩散能力和较高的持久性。罗氏锦蛇最为明显，其合并分析表明，大多数种群在整个更新世气候循环中都保持隔离状态。形态上的差异，主要是在体型上，在罗氏锦蛇的孤立种群中比在 L. coggeri 中更为明显。这些结果突出了孤立山地种群的生物多样性价值，并支持了热带山地地区由于对过去气候变化的适应而具有高水平的窄范围分类群的一般假设。
