Department of Basic Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, Missouri, United States of America.
Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign, Champaign, Illinois, United States of America.
PLoS One. 2022 Mar 24;17(3):e0265666. doi: 10.1371/journal.pone.0265666. eCollection 2022.
As anthropogenic changes continue to ecologically stress wildlife, obtaining measures of gene flow and genetic diversity are crucial for evaluating population trends and considering management and conservation strategies for small, imperiled populations. In our study, we conducted a molecular assessment to expand on previous work to elucidate patterns of diversity and connectivity in the remaining disjunct Eastern Massasauga Rattlesnake (Sistrurus catenatus) hibernacula in Illinois. We assayed genetic data for 327 samples collected during 1999-2015 from the Carlyle Lake study area across 21 microsatellite loci. We found hibernacula formed distinct genetic clusters corresponding to the three main study areas (Dam Recreation Areas, Eldon Hazlet State Park, and South Shore State Park). Genetic structuring and low estimates of dispersal indicated that connectivity among these study areas is limited and each is demographically independent. Hibernacula exhibited moderate levels of heterozygosity (0.60-0.73), but estimates of effective population size (5.2-41.0) were low and track census sizes generated via long-term mark-recapture data. Hibernacula at Carlyle Lake, which represent the only Eastern Massasauga remaining in Illinois, are vulnerable to future loss of genetic diversity through lack of gene flow as well as demographic and environmental stochastic processes. Our work highlights the need to include population-level genetic data in recovery planning and suggests that recovery efforts should focus on managing the three major study areas as separate conservation units in order to preserve and maintain long-term adaptive potential of these populations. Specific management goals should include improving connectivity among hibernacula, maintaining existing wet grassland habitat, and minimizing anthropogenic sources of mortality caused by habitat management (e.g., mowing, prescribed fire) and recreational activities. Our molecular study provides additional details about demographic parameters and connectivity at Carlyle Lake that can be used to guide recovery of Eastern Massasauga in Illinois and throughout its range.
随着人为变化继续对野生动物造成生态压力，获取基因流动和遗传多样性的测量值对于评估种群趋势以及考虑小而受威胁的种群的管理和保护策略至关重要。在我们的研究中，我们进行了分子评估，以扩展以前的工作，阐明伊利诺伊州剩余的分散的东部马萨诸塞响尾蛇（Sistrurus catenatus）冬眠地的多样性和连通性模式。我们对 1999 年至 2015 年期间在卡莱尔湖研究区域收集的 327 个样本进行了遗传数据分析，这些样本分布在 21 个微卫星基因座上。我们发现冬眠地形成了与三个主要研究区域（大坝娱乐区、埃尔顿·黑兹利特州立公园和南岸州立公园）相对应的独特遗传聚类。遗传结构和扩散的低估计表明，这些研究区域之间的连通性有限，每个区域在人口统计学上都是独立的。冬眠地表现出中等水平的杂合度（0.60-0.73），但有效种群大小的估计值（5.2-41.0）较低，且通过长期标记-重捕数据生成的种群数量也较低。卡莱尔湖的冬眠地是伊利诺伊州仅剩的东部马萨诸塞响尾蛇的栖息地，由于缺乏基因流动以及人口和环境随机过程，它们容易在未来失去遗传多样性。我们的研究工作强调了在恢复规划中纳入种群遗传数据的必要性，并表明恢复工作应侧重于将三个主要研究区域作为单独的保护单位进行管理，以保护和维持这些种群的长期适应潜力。具体的管理目标应包括提高冬眠地之间的连通性，维持现有的湿草地生境，并最大限度地减少由栖息地管理（例如割草、规定的火灾）和娱乐活动造成的人为死亡源。我们的分子研究提供了有关卡莱尔湖的人口参数和连通性的更多详细信息，可用于指导伊利诺伊州和整个东部马萨诸塞响尾蛇的恢复。
