Biology Department, College of Staten Island/CUNY, Staten Island, NY 10314, USA.
Mol Ecol. 2010 Dec;19(24):5321-3. doi: 10.1111/j.1365-294X.2010.04861.x.
Separating historical effects from recent anthropogenic pressures on population structure is paramount for understanding how species have persisted over time and how conservation efforts should best proceed. In this issue of Molecular Ecology, Chiucchi & Gibbs (2010) have separated the impacts of ancient and modern habitat fragmentation on genetic structure and migration rates in an endangered species of rattlesnake, the eastern massasauga (Sistrurus catenatus). Previous studies have ignored ancient processes, estimated genetic isolation and migration using collections from different timescales, used markers with different rates of evolution or compared contemporary populations in both continuous and fragmented habitats (Keyghobadi 2007). Here, Chiucchi & Gibbs (2010) estimate migration parameters from microsatellites at two timescales using coalescent methods. Results strongly suggest that massasaugas are characterized by the low levels of migration with strong regional and range-wide differences, typical of many organisms residing in the patches of habitat surrounded by seas of agriculture, but that these patterns have existed since the Pleistocene. The novel methodology and hypotheses addressed in Chiucchi & Gibbs (2010) highlight future avenues for examining the impacts of fragmentation through time.
将历史效应与近期人为压力对种群结构的影响区分开来，对于了解物种如何在时间上得以延续以及保护工作应如何最好地开展至关重要。在本期《分子生态学》中，Chiucchi 和 Gibbs（2010）研究了濒危响尾蛇物种——东部菱背响尾蛇（Sistrurus catenatus）的遗传结构和迁移率，将古代和现代生境破碎化的影响区分开来。之前的研究忽略了古老的过程，在不同的时间尺度上使用不同的数据集来估计遗传隔离和迁移率，使用进化速度不同的标记物，或者比较连续和破碎化栖息地中的当代种群（Keyghobadi 2007）。在这里，Chiucchi 和 Gibbs（2010）使用合并方法在两个时间尺度上从微卫星估计迁移参数。研究结果强烈表明，菱背响尾蛇的迁移水平较低，区域和范围差异较大，这是许多生活在被农业包围的栖息地斑块中的生物的典型特征，但这些模式自更新世以来就一直存在。Chiucchi 和 Gibbs（2010）提出的新颖方法和假设突出了未来通过时间检验破碎化影响的途径。
