Genetic structure is stronger across human-impacted habitats than among islands in the coral Porites lobata

PeerJ

article

Kaho H. Tisthammer¹  Zac H. Forsman³  Robert J. Toonen³  Robert H. Richmond¹ 

[1] Kewalo Marine Laboratory, University of Hawaii at Manoa;Department of Biology, San Francisco State University;Hawaii Institute of Marine Biology, University of Hawaii at Manoa

关键词: Coral reefs;    Anthropogenic impacts;    Population genetics;    Hawaii;    Lobe coral;    Isolation by distance;    Isolation by environment;    Local adaptation;    Gene flow;   

DOI  :  10.7717/peerj.8550

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

We examined genetic structure in the lobe coral Porites lobata among pairs of highly variable and high-stress nearshore sites and adjacent less variable and less impacted offshore sites on the islands of Oahu and Maui, Hawaii. Using an analysis of molecular variance framework, we tested whether populations were more structured by geographic distance or environmental extremes. The genetic patterns we observed followed isolation by environment, where nearshore and adjacent offshore populations showed significant genetic structure at both locations (AMOVA FST = 0.04∼0.19, P < 0.001), but no significant isolation by distance between islands. Strikingly, corals from the two nearshore sites with higher levels of environmental stressors on different islands over 100 km apart with similar environmentally stressful conditions were genetically closer (FST = 0.0, P = 0.73) than those within a single location less than 2 km apart (FST = 0.04∼0.08, P < 0.01). In contrast, a third site with a less impacted nearshore site (i.e., less pronounced environmental gradient) showed no significant structure from the offshore comparison. Our results show much stronger support for environment than distance separating these populations. Our finding suggests that ecological boundaries from human impacts may play a role in forming genetic structure in the coastal environment, and that genetic divergence in the absence of geographical barriers to gene flow might be explained by selective pressure across contrasting habitats.

【 授权许可】

CC BY