The Caddo Madtom, Noturus taylori, is endemic to three river drainages of the Ouachita Highlands in the southeastern United States. Conservation concern for N. taylori has been heightened by recent studies based on analyses of allozyme data suggesting population decline and a possible extirpation event, which lead to N. taylori petitioned for listing under the Endangered Species Act in 2011. The objective of this study was to determine if contemporary factors, historic processes, or a combination of both, using microsatellite DNA loci and mitochondrial (mt) DNA, have influenced patterns of genetic structuring for N. taylori to better inform conservation management strategies. Phylogeographic and Bayesian cluster analyses suggest that genetic structuring between Caddo and Ouachita river drainages was shaped by historical processes prior to construction of reservoir dams that dissect the drainages. We found no evidence that reservoir dams influenced contemporary patterns of genetic structure, thus it is likely that larger river courses, and life-history characteristics conducive to headwater habitats, play important roles in limiting gene flow between drainages, and to some extent within drainages. Genetic diversity of N. taylori was relatively high compared to other endangered madtom species; however, compared to the Ouachita River population, genetic diversity was significantly lower for the Caddo River population. Collectively, these results suggest that N. taylori populations are not heavily impaired, and the genetic variation and structuring is most attributable to historic processes. However, the endemic status and narrowly fragmented distribution still renders N. taylori populations vulnerable to extirpation or extinction by stochastic events.

Caddo Madtom（Noturus taylori）是美国东南部Ouachita高地的三条河流排水特有的地方。最近的研究基于对同工酶数据的分析，表明种群数量下降和可能的灭绝事件，使得对泰勒猪笼草的保护更加关注，这导致泰勒猪笼草在2011年根据《濒危物种法》被要求列入名录。本研究的目的是确定使用微卫星DNA基因座和线粒体（mt）DNA的当代因素，历史过程或两者的结合是否影响了泰勒猪笼草的基因结构模式更好地告知保护管理策略。系统记录和贝叶斯聚类分析表明，在建造解剖河流的水坝之前，卡多河与瓦希塔河之间的遗传结构受历史过程影响。我们没有发现证据表明水库大坝影响了当代的遗传结构模式，因此，较大的河道和有利于源头生境的生活史特征很可能在限制排水沟之间以及排水沟中的基因流中起重要作用。泰勒猪笼草的遗传多样性与其他濒临灭绝的动植物相比，相对较高；但是，与瓦基塔河种群相比，卡多河种群的遗传多样性明显较低。总体而言，这些结果表明，泰勒猪笼草种群并未受到严重损害，遗传变异和结构最可归因于历史进程。然而，地方病的状况和狭窄的分布仍然使泰勒猪笼草种群容易因随机事件而灭绝或灭绝。