Biddy Austin R, Manthey Joseph D, Ware Jessica L, McIntyre Nancy E
Department of Biological Sciences Texas Tech University Lubbock Texas USA.
Department of Biology University of Alabama at Birmingham Birmingham Alabama USA.
Ecol Evol. 2024 Aug 6;14(8):e70107. doi: 10.1002/ece3.70107. eCollection 2024 Aug.
Understanding how past and current environmental conditions shape the demographic and genetic distributions of organisms facilitates our predictions of how future environmental patterns may affect populations. The Canyon Rubyspot damselfly (Odonata: Zygoptera: ) is an insect with a range distribution from Colombia to the arid southwestern United States, where it inhabits shaded mountain streams in the arid southwestern United States. Past spatial fragmentation of habitat and limited dispersal capacity of may cause population isolation and genetic differentiation, and projected climate change may exacerbate isolation by further restricting the species' distribution. We constructed species distribution models (SDMs) based on occurrences of and environmental variables characterizing the species' niche. We inferred seven current potential population clusters isolated by unsuitable habitat. Paleoclimate models indicated habitat contiguity in past conditions; projected models indicated some habitat fragmentation in future scenarios. Seventy-eight individuals from six of the current clusters were sequenced via ddRADseq and processed with Stacks. Principal components and phylogeographic analyses resolved three subpopulations; resolved four subpopulations. values were low (<0.05) for nearby populations and >0.15 for populations separated by expanses of unsuitable habitat. Isolation by distance was an existing but weak factor in determining genomic structure; isolation by environment and the intervening landscape explained a significant proportion of genetic distance. populations were shown to be isolated by a lack of tree canopy coverage, an important habitat predictor for oviposition and territoriality. Thus, populations are likely separated and are genetically isolated. Integrating SDMs with landscape genetics allowed us to identify populations separated by distance and unsuitable habitat, explaining population genetic patterns and probable fates for populations under future climate scenarios.
了解过去和当前的环境条件如何塑造生物的种群统计学和遗传分布，有助于我们预测未来的环境模式可能如何影响种群。峡谷红宝石豆娘（蜻蜓目：均翅亚目：）是一种昆虫，分布范围从哥伦比亚到美国干旱的西南部，它栖息在美国干旱西南部有树荫的山间溪流中。过去栖息地的空间破碎化以及其有限的扩散能力可能导致种群隔离和遗传分化，而预计的气候变化可能通过进一步限制该物种的分布来加剧隔离。我们基于该物种的出现情况和表征其生态位的环境变量构建了物种分布模型（SDM）。我们推断出七个当前潜在的种群集群，它们被不适合的栖息地隔开。古气候模型表明过去条件下栖息地是连续的；预测模型表明在未来情景中会出现一些栖息地破碎化。通过ddRADseq对来自当前六个集群的78个个体进行测序，并使用Stacks进行处理。主成分分析和系统地理学分析解析出三个亚种群；解析出四个亚种群。相邻种群的Fst值较低（<0.05），而被大片不适合栖息地隔开的种群的Fst值>0.15。距离隔离是决定基因组结构的一个现有但较弱的因素；环境隔离和中间景观解释了很大一部分遗传距离。研究表明，豆娘种群因缺乏树冠覆盖而被隔离，树冠覆盖是产卵和领地行为的重要栖息地预测指标。因此，豆娘种群可能是隔离的且在遗传上是孤立的。将SDM与景观遗传学相结合，使我们能够识别出因距离和不适合栖息地而隔离的种群，解释种群遗传模式以及未来气候情景下种群的可能命运。
