Parvizi Elaheh, Keikhosravi Alireza, Naderloo Reza, Solhjouy-Fard Samaneh, Sheibak Farahnaz, Schubart Christoph D
School of Biology, College of Science University of Tehran Tehran Iran.
Present address: Department of Zoology University of Otago Dunedin New Zealand.
Ecol Evol. 2019 Mar 26;9(8):4749-4759. doi: 10.1002/ece3.5078. eCollection 2019 Apr.
Refugia are critical for the maintenance of biodiversity during the periods of Quaternary climatic oscillations. The long-term persistence of refugial populations in a large continuous refugium has resulted in a homogenous pattern of genetic structure among populations, while highly structured evolutionary lineages characterize the restriction of refugial populations to smaller subrefugia. These mechanisms have resulted in the identification of hot spots of biodiversity within putative glacial refugia. We studied phylogeography of (Brachyura: Potamidae) in the drainages of the western Caucasus biodiversity hot spot (i.e., Colchis and the Caucasus) to infer spatial genetic structure and potential refugia for a freshwater crab in this region. These areas have traditionally considered as a refugium due to the presence of Tertiary relict species. We integrated population genetic data and historical demographic analysis from cytochrome oxidase subunit I sequences and paleoclimatic data from species distribution modeling (SDM). The results revealed the lack of phylogeographic structure and provided evidence for demographic expansion. The SDM presented a rather homogenous and large refugium that extended from northeast Turkey to Colchis during the last glacial period. In contrast to these findings, previous phylogeographic study on of the eastern Caucasus biodiversity hot spot (i.e., Hyrcania) identified multiple independent refugia. By combining these results, we explain the significance of this important western Palearctic hot spot of biological diversity in shaping the geographic distribution of intraspecific genetic diversity in a freshwater taxon.
避难所对于第四纪气候振荡期间生物多样性的维持至关重要。大型连续避难所中避难种群的长期存续导致了种群间遗传结构的同质化模式，而高度结构化的进化谱系则是避难种群局限于较小的次避难所的特征。这些机制促成了在假定的冰川避难所内确定生物多样性热点。我们研究了西高加索生物多样性热点地区（即科尔基斯和高加索地区）排水系统中一种淡水蟹（短尾派：溪蟹科）的系统地理学，以推断该地区淡水蟹的空间遗传结构和潜在避难所。由于存在第三纪残遗物种，这些地区传统上被视为避难所。我们整合了来自细胞色素氧化酶亚基I序列的种群遗传数据和历史种群动态分析以及来自物种分布模型（SDM）的古气候数据。结果显示缺乏系统地理结构，并为种群扩张提供了证据。物种分布模型呈现出一个相当同质化且广阔的避难所，在末次冰期从土耳其东北部延伸至科尔基斯。与这些发现形成对比的是，先前对东高加索生物多样性热点地区（即希尔卡尼亚）同一种淡水蟹的系统地理学研究确定了多个独立的避难所。通过综合这些结果，我们解释了这个重要的西古北区生物多样性热点在塑造淡水分类单元种内遗传多样性地理分布方面所具有的重要意义。
