SPEARS, T.; Florida State University: Comparisons of population genetic structure for three large branchiopods co-occurring in ephemeral pools in the Lake Munson Sandhills Region of the Apalachicola National Forest.

The Lake Munson Sandhills Region of the Apalachicola National Forest south of Tallahassee, Florida is characterized by numerous ephemeral pools, many of which contain so-called “large” branchiopod crustaceans that emerge from dried cysts in the soil when the pools fill after periods of heavy rain. Three species of large branchiopods have been identified from this region, each representing a different order: two species of clam shrimp, Lynceus gracilicornis (Order Laevicaudata) and Limnadia lenticularis (Order Spinicaudata), and a fairy shrimp, Streptocephalus sealii (Order Anostraca). Initial surveys have identified ponds that contain one, two, or all three species. Among the three species, L. gracilicornis is less common. Nucleotide sequence data were obtained for a 675 base-pair portion of the mitochondrial cytochrome oxidase subunit I gene for multiple representatives of the three species from pools in which all three co-occurred to permit a comparison of genetic diversity within and among pools. Sequence analyses indicate population structure among pools within even a relatively small (4.5 km x 1.5 km) area, suggesting that the pools that were surveyed do not represent one large homogeneous population for any given species. Patterns of population structure were more similar for L. lenticularis and S. sealii, with L. gracilicornis exhibiting a completely different pattern for the same pools. Hence, gene flow between pools is not uniform across species, with L. gracilicornis showing more limited gene flow. These findings are potentially important for designing conservation and management strategies for these wetland areas.