Population structure of the scleractinian coral, Montastraea cavernosa, in southeast Florida

The persistence of scleractinian coral populations on the Florida Reef
Tract (FRT) is controlled in part by metapopulation dynamics and larval
dispersal. Nine polymorphic microsatellite loci were analyzed to identify
contemporary population structure and gene flow as well as historical
migration rates of Montastraea cavernosa at five sites off Martin, Palm
Beach, and Broward counties in southeast Florida. The sampled populations
demonstrated evidence of genetic isolation by distance over a geographic
range of 85 km. Population genetic structure was divided into two genetic
clusters, northern and southern, with admixture along a latitudinal
gradient. Historical migration models indicated likely panmixia throughout
all sites sampled, identifying a potential reduction in connectivity among
the sampled populations through time. Though M. cavernosa populations
demonstrated evidence of historical connectivity, contemporary patterns of
isolation by distance suggest that effective management will require
localized actions to maximize the likelihood of sustaining individual
populations in the northern FRT. Given the results of this study, coupled
with recent coral mortality events in the region, we recommend regional
conservation efforts and management initiatives throughout southeast
Florida within a more comprehensive FRT-wide management network.

佛罗里达礁区（Florida Reef Tract, FRT）内石珊瑚（scleractinian coral）种群的存续，在一定程度上受集合种群动态（metapopulation dynamics）与幼虫扩散（larval dispersal）调控。本研究对9个多态性微卫星位点（polymorphic microsatellite loci）进行分析，旨在厘清佛罗里达东南部马丁县、棕榈滩县及布劳沃德县周边近海5个采样点中，穴形星珊瑚（Montastraea cavernosa，下文简称M. cavernosa）的当代种群结构、基因流及历史迁移速率。所采样的种群在85公里的地理跨度内，呈现出距离隔离（isolation by distance）的遗传特征。种群遗传结构可划分为南北两个遗传簇（genetic clusters），并沿纬度梯度存在遗传混合（admixture）现象。历史迁移模型结果显示，所有采样点历史上均处于随机交配（panmixia）状态，表明采样种群间的连通性随时间推移有所下降。尽管穴形星珊瑚种群存在历史连通性的相关证据，但当代的距离隔离格局提示，若要实施有效管理，需采取本地化保护举措，以提升佛罗里达礁区北部种群的存续概率。结合本研究结果与该区域近期发生的珊瑚死亡事件，我们建议在更全面的佛罗里达礁区全域管理框架内，于佛罗里达东南部开展区域性保护行动与管理方案。