Studying ecological change using genetic diversity
Genetic variation in T. saltator was studied both over time and in different sites. These are small crustaceans which live in the supralittoral zone of sandy beaches. This is the area above the spring high tide mark, which is splashed by the sea, but not submerged under the waves. Wide genetic variation was identified among populations of T. saltator sampled from different sites. Those samples taken along the beach at Uccellina, Tuscany, also showed wide genetic variation. At some sites T. saltator could not be found. This was most likely as a result of coastal erosion affecting the viability of the local subpopulation of sandhoppers, which can also reduce genetic variability. A reduction in the population size of a species and loss of genetic diversity can run the risk of local extinction. Other factors, such as man-made pressures on the ecosystem, can have a similar impact on genetic variation in a population. It should be noted, that some samples of T. saltator were collected from beaches that were extremely popular with tourists. In general, data collected for this particular part of the MED-CORE project agreed with earlier laboratory based results for T. saltator. Both new data and past results indicate that a stable sand dune belt and absence of human activity on a beach contribute to maintaining genetic variability in sandhopper populations.
