Macroinvertebrate and fish communities in the watershed of a re-constructed Mediterranean water body: link to the ecological potential.

The role of benthic macroinvertebrate and fish communities for assessing the ecological quality of an artificial re-constructed, after 50 years of dryness, Mediterranean water body (Karla Reservoir, Greece) is presented. Moreover, we provide knowledge on the structure of the biological communities and their functioning role, for inspiring feature actions that will contribute to biodiversity protection and ecosystem services. Water (physicochemical parameters), benthic macroinvertebrates, and fish were monitored during a 2-year survey (2013-2015) in Karla and Kalamaki reservoirs and the inflowing ditches. A clear temporal pattern was evident for all sampling stations studied, differentiating the low- and high-flow period samples as to their physicochemical parameters. Redundancy analysis (RDA) revealed NO3-N, total nitrogen and total dissolved phosphorous as the most significant environmental parameters in explaining benthic invertebrate variance in ditches. Generally, tolerant to organic pollution macroinvertebrate taxa were abundant in ditches and reservoirs, while the fish fauna in Karla was composed almost exclusively of planktivorous and invertivorous species. Macroinvertebrate (GLBiI) and fish (GLFI) indices classified the ecological quality of Karla Reservoir as "poor" while ditches were classified as "bad" according to HESY-2. The anthropogenic pressures applied in the catchment and the benefits of improving water quality are discussed in the context of the implementation of Water Framework Directive 2000/60/EC for introducing sustainable management plans, taking into account some ecological restoration principles.