Abundance, zonation and ecological indices of a coleopteran community from a sandy beach-dune ecosystem of the southern adriatic coast, Italy

A study on the Coleoptera community inhabiting a beach-dune ecosystem was carried out at Isola Varano, a site located along the southern Adriatic coast of Italy (Apulia). During 2002 bimonthly samples were taken using a standard system of traps: two transects with pitfall traps placed from the sealine limits to the first dune were used to collect spontaneously active individuals whereas core samples were taken in correspondence with each pitfall trap to sample burrowed beetles. Environmental variables such as beach profile, exposure, orientation, length, width, slope, mean grain size and dune height were also recorded. Temporal and spatial patterns were assessed for the most important Coleoptera species. Species were also studied both quantitatively and qualitatively using ecological indices: frequency and relative abundance were calculated together with species richness, ? and ? diversity, the evenness of the community and dominance index. Comparisons with other beach localities over the Mediterranean basin showed that the coleopteran community of Isola Varano followed the general trends, both in space and time, that occurred for other sites even if lower diversity values were obtained. The presence of certain bioindicator species indicated a relatively good state of beach health but the impoverished dune fauna showed that the habitat was under a stressful condition due to the presence of a pinewood plantation in the retrodunal areas.