Patterns of functional diversity of macroinvertebrates across three aquatic ecosystem types, NE mediterranean

This study investigates the variation patterns of the functional structure of macroinvertebrate guilds in relation to the taxonomic one, across aquatic ecosystem types and along the salinity gradient, from freshwater to marine, as well as the resulting implications for guild organization and energy flows. Synoptic sampling was carried out on Corfu Island (Greece) using the leaf-pack technique at 30 aquatic ecosystems, including freshwater, lagoon, and marine sites, and the following were analyzed: i. taxonomic composition and population abundance; ii. trophic guild composition and relative abundance; and iii. body size spectra and size patterns. The following variation patterns across the three ecosystem types were observed: a. the trophic guild composition and body size spectra were more conservative than the taxonomic composition within and among ecosystem types; trophic guild and size spectra composition were more similar between river and lagoon ecosystem types than with marine ones; b. dominance as regards resource exploitation of large species over smaller ones was inferred at all sites; and, c. higher body size-specific density of individuals was consistently observed in lagoon rather than freshwater and marine ecosystems. The results support previous findings suggesting a common hierarchical organization of benthic macroinvertebrate guilds in aquatic ecosystems and show that higher energy density is transferred to benthic macroinvertebrates in lagoon ecosystem types compared to both freshwater and marine ones.