Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, USA.
Mol Ecol. 2019 Jun;28(11):2746-2756. doi: 10.1111/mec.15109. Epub 2019 Jun 18.
Connectivity is central to ecology and evolution as it focuses on the movement of individuals or genes across landscapes. Genetic connectivity approaches aim to understand gene flow but often estimate it indirectly based on metrics of genetic differentiation, which can also be affected by other evolutionary forces such as genetic drift. Gene flow and genetic drift are driven by separate ecological mechanisms with potentially differing effects on genetic differentiation and interpretations of genetic connectivity. The ecological mechanisms contributing to gene flow and genetic drift are primarily effective dispersal, or movement followed by successful reproduction, and the number of breeders in a local population, N , respectively. Yet, rarely are these ecological mechanisms and genetic connectivity measured simultaneously across landscapes. We examine the roles of effective dispersal and N on genetic connectivity across the entire range of the endangered snail kite (Rostrhamus sociabilis plumbeus), between 2006-2015. We find that both N and effective dispersal are important predictors of genetic connectivity across this landscape, but that N has a 3 × stronger effect on genetic connectivity. Furthermore, N is positively correlated with heterozygosity and allelic richness within patches, suggesting a potentially important role of genetic drift, in addition to gene flow, on genetic connectivity. These results emphasize that conservation efforts should focus on not only between-patch processes of movement but also within-patch processes regarding habitat quality and local population size for increasing genetic connectivity.
连通性是生态学和进化学的核心，因为它关注的是个体或基因在景观中的移动。遗传连通性方法旨在理解基因流，但通常是通过遗传分化的指标间接估计的，而遗传分化也可能受到其他进化力量的影响，如遗传漂变。基因流和遗传漂变是由不同的生态机制驱动的，它们对遗传分化和遗传连通性的解释可能有不同的影响。促进基因流和遗传漂变的生态机制主要是有效的扩散，或者是在成功繁殖后的移动，以及当地种群的繁殖者数量 N 。然而，在景观中很少同时测量这些生态机制和遗传连通性。我们在 2006 年至 2015 年间，检查了有效扩散和 N 在濒危蜗牛鸢（Rostrhamus sociabilis plumbeus）整个范围内对遗传连通性的作用。我们发现，N 和有效扩散都是影响该景观遗传连通性的重要预测因素，但 N 对遗传连通性的影响是有效扩散的 3 倍。此外，N 与斑块内的杂合度和等位基因丰富度呈正相关，这表明除了基因流之外，遗传漂变对遗传连通性也可能有重要作用。这些结果强调，保护工作不仅应侧重于斑块间的移动过程，还应侧重于斑块内有关栖息地质量和当地种群大小的过程，以提高遗传连通性。
