POPULATION GENETIC DIVERSITY OF SEAGRASS ENHALUS ACOROIDES: A MEASURE OF MARINE CONNECTIVITY IN THE MARIANA ARCHIPELAGO

Seagrass meadows provide critical ecosystem services but are in worldwide decline from changes in their environmental conditions. This decline has resulted in seagrass loss, meadow fragmentation, and loss of gene flow between meadows, especially in the Western Indo-Pacific. This study focuses on the connectivity of the dominant seagrass species Enhalus acoroides in Saipan and Guam, the largest and most populated islands in the Northern Mariana Islands. I hypothesized the populations would be well connected within the islands and to the larger population in Southeast Asia. Microsatellite markers are genetic tools, to estimate population diversity at different loci. There was no variability found between the seven meadows of Saipan and the four in Guam at two loci. A number of explanations for this low variability are possible: populations are well-connected currently or were well-connected in the recent past, a bottleneck effect, restoration efforts have resulted in plantings of a single genotype across many sites, and/or the genetic diversity of these populations may have been underestimated because only two loci were considered. Thorough evaluations of marine connectivity are essential for the longterm protection of genetic diversity and restoration of fragmented meadows.