Rhizophora mangle (Red Mangrove) Population Genetic Structure in The Bahamas

Lundy, A. L. (2021) Rhizophora mangle (Red Mangrove) Population Genetic Structure in The Bahamas. Masters by Research thesis (MSc), Manchester Metropolitan University.

Preview

Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (3MB) | Preview

Abstract

Rhizophora mangle, a red mangrove, grows naturally throughout the Bahamian archipelago. Genetic research on the species shows The Bahamas is likely historically linked to both Florida and wider Caribbean populations, however, this conclusion is based on data from a single sample site in The Bahamas. The current study aims to identify the population genetic structure of R. mangle throughout the country by sampling multiple islands. A total of 327 trees were sampled across fifteen sites from twelve islands in the archipelago and analyzed using 15 microsatellite markers. At least four genetically distinct clusters of R. mangle were identified in The Bahamas. The clusters appeared to align with the geography of the country in two main ways, by the KöppenGeiger climate classification and by the latitude and longitude. The presence of the shallow sand banks, the Great Bahama Bank and the Little Bahama Bank, also appears to have some influence on the population structure. The most genetically distinct sites were Inagua, the most southern island in the archipelago, and West Grand Bahama, one of the northern islands. These sites were geographically the furthest apart at a minimum distance of 514 miles. This indicates that isolation by distance may play a role in the population structure. Conversely some sample sites that are in close proximity to each other range from moderately to significantly different. For instance, the sample sites on Conception Island and San Salvador island are approximately 42 miles apart but the sites are in different genetic clusters. This indicates that isolation by environment may also be playing a role in the population structure in the country. The findings of this research should be used to inform restoration projects focused on planting red mangroves in The Bahamas to ensure maintenance of the underlying population genetic structure.