Habitat types and distribution of benthic macroinvertebrates in a transitional water ecosystem: Alimini Grande (Puglia, Italy)

1 - It is well-known that the variation patterns of structures and processes depend on scale – whether this be intrinsic or imposed by the observation methods. Transitional water ecosystems, being ecotonal systems, represent a suitable model for studying such relations. 2 - The aims of this study were: 1) to describe the macro-zoobenthic community of Lake “Alimini Grande” and 2) to analyze its patterns of spatial and temporal variation. 3 - The macro-zoobenthic community was sampled in three benthic habitat types (2 stations per type, five replicates per station) using a sediment box-corer, in two seasons (fall and spring). 4 - The density data were used for a qualitative-quantitative description of the community and subsequently underwent univariate and multivariate analyses to determine patterns of variation among replicates, stations, habitat types and seasons. A total of 28 taxa were recorded, subdivided into 3 feeding groups; filterers were the most common in terms of abundance and number of taxa. 5 - The distribution of benthic macroinvertebrates was found to be influenced by both temporal and spatial factors. The habitat type with the highest density and taxonomic richness exhibited significant intra-type heterogeneity of the community, suggesting that habitat type could be distinguished at a finer scale than the one previously adopted.