Sinclair Elizabeth A, Hovey Renae K, Krauss Siegfried L, Anthony Janet M, Waycott Michelle, Kendrick Gary A
School of Biological Sciences University of Western Australia Crawley Western Australia Australia.
Oceans Institute, University of Western Australia Crawley Western Australia Australia.
Ecol Evol. 2023 Mar 19;13(3):e9900. doi: 10.1002/ece3.9900. eCollection 2023 Mar.
Historical and contemporary processes drive spatial patterns of genetic diversity. These include climate-driven range shifts and gene flow mediated by biogeographical influences on dispersal. Assessments that integrate these drivers are uncommon, but critical for testing biogeographic hypotheses. Here, we characterize intraspecific genetic diversity and spatial structure across the entire distribution of a temperate seagrass to test marine biogeographic concepts for southern Australia. Predictive modeling was used to contrast the current distribution to its historical distribution during the Last Glacial Maximum (LGM). Spatial genetic structure was estimated for 44 sampled meadows from across the geographical range of the species using nine microsatellite loci. Historical and contemporary distributions were similar, with the exception of the Bass Strait. Genetic clustering was consistent with the three currently recognized biogeographic provinces and largely consistent with the finer-scale IMCRA bioregions. Discrepancies were found within the Flindersian province and southwest IMCRA bioregion, while two regions of admixture coincided with transitional IMCRA bioregions. Clonal diversity was highly variable but positively associated with latitude. Genetic differentiation among meadows was significantly associated with oceanographic distance. Our approach suggests how shared seascape drivers have influenced the capacity of to effectively track sea level changes associated with natural climate cycles over millennia, and in particular, the recolonization of meadows across the Continental Shelf following the LGM. Genetic structure associated with IMCRA bioregions reflects the presence of stable biogeographic barriers, such as oceanic upwellings. This study highlights the importance of biogeography to infer the role of historical drivers in shaping extant diversity and structure.
历史和当代进程驱动着遗传多样性的空间格局。这些进程包括气候驱动的分布范围变化以及由生物地理对扩散的影响介导的基因流。整合这些驱动因素的评估并不常见，但对于检验生物地理假说至关重要。在这里，我们描述了一种温带海草整个分布范围内的种内遗传多样性和空间结构，以检验澳大利亚南部的海洋生物地理概念。使用预测模型将当前分布与其末次盛冰期（LGM）期间的历史分布进行对比。利用9个微卫星位点对该物种地理范围内44个采样草甸的空间遗传结构进行了估计。历史分布和当代分布相似，但巴斯海峡除外。遗传聚类与目前公认的三个生物地理省份一致，并且在很大程度上与更精细尺度的IMCRA生物区域一致。在弗林德斯省和IMCRA生物区域西南部发现了差异，而两个混合区域与过渡性IMCRA生物区域重合。克隆多样性高度可变，但与纬度呈正相关。草甸之间的遗传分化与海洋学距离显著相关。我们的方法表明，共享的海景驱动因素如何影响了[物种名称未明确]在数千年里有效追踪与自然气候周期相关的海平面变化的能力，特别是末次盛冰期后大陆架上草甸的重新定殖。与IMCRA生物区域相关的遗传结构反映了稳定的生物地理屏障的存在，如海洋上升流。这项研究强调了生物地理学对于推断历史驱动因素在塑造现存多样性和结构中的作用的重要性。
