Departamento de Biología de La Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, B.C, México.
Naturwissenschaften. 2024 Jul 15;111(4):39. doi: 10.1007/s00114-024-01925-5.
Coastal dunes are unique habitats, threatened by human activities. In biogeographical terms, coastal dunes are habitat islands, being discrete and distinct patches of similar habitat among themselves, separated from each other by a different type of habitat. Furthermore, coastal dunes harbor endemic species, adapted to living solely in the habitats found on specific dune systems. For example, the honeypot ant Myrmecocystus baja is endemic and restricted to coastal dunes of Mexico's Baja California Pacific coast. This ecological and biogeographical scenario led to the questions whether their geographical isolation is reflected in their genetic diversity and structuring, and how their demographic history is related with the formation of the dune system habitats. To answer these questions, population genetic, isolation-with-migration, and phylogeographical analyses were carried out, based on mitochondrial and five nuclear intronic markers. Minimal gene flow was detected only between two of the dune systems sampled; otherwise, the M. baja populations were found to be isolated and genetically structured, and their divergence generally pre-dated the modern-day dune systems. It is therefore highly likely that these ants were already present in paleodunes and that each of the populations was established from founder populations as the dunes formed. These findings highlight the importance of coastal dunes for species such as the honeypot ant from Baja California, in promoting genetic differentiation.
滨海沙丘是独特的栖息地，受到人类活动的威胁。从生物地理学的角度来看，滨海沙丘是栖息地岛屿，它们彼此之间是离散而独特的相似栖息地斑块，彼此之间被不同类型的栖息地隔开。此外，滨海沙丘还栖息着特有物种，这些物种适应于仅在特定沙丘系统中的栖息地中生存。例如，蜜罐蚁 Myrmecocystus baja 就是特有种，仅分布于墨西哥下加利福尼亚太平洋海岸的滨海沙丘中。这种生态和生物地理情景引发了以下问题：它们的地理隔离是否反映在遗传多样性和结构上，以及它们的种群历史与沙丘系统栖息地的形成有何关系。为了回答这些问题，基于线粒体和五个核内含子标记，进行了种群遗传、隔离-迁移和系统地理学分析。仅在两个采样的沙丘系统之间检测到最小的基因流；否则，M. baja 种群被发现是隔离和遗传结构的，它们的分化通常早于现代沙丘系统。因此，这些蚂蚁很可能已经存在于古沙丘中，并且每个种群都是随着沙丘的形成由创始种群建立的。这些发现强调了滨海沙丘对下加利福尼亚蜜罐蚁等物种的重要性，促进了遗传分化。
