Effects of habitat management and restoration on freshwater ecosystem polulation dynamics

Although water quality improvement is generally the primary objective of treatment wetlands, the creation of habitats is an inevitable outcome of these projects. Macroinvertebrate are often early colonists of new created wetlands, with abundance and diversity approaching high levels within a few years from wetland construction. A deeper knowledge of the biodiversity hosted in these environments is needed to evaluate if newly created ponds are appropriate management tools for biological conservation. The effectiveness of the interventions provided by Parco Pineta di Appiano Gentile e Tradate (a regional park in Lombardy, Italy) in freshwater ecosystem management and restoration has been evaluated, considering a set of natural, artificial and constructed wetlands spread within the park territory. Considering the macroinvertebrate community and analyzing the biodiversity hosted in all the considered wetlands, no significant differences were found between artificial and natural ecosystems. Even the constructed wetlands, which were characterized by low water quality and higher pollutants concentrations, presented a biodiversity level which in some cases exceeded that one present in natural ecosystems. Even though biodiversity was similar between wetland typologies, differences in community compositions have been enlightened. The macroinvertebrate community assemblages seemed to be influenced more by the geographical and hydromorphological variables of the ecosystem rather than the physicochemical water characteristics. In particular, water body area and habitat heterogeneity resulted to be the most important variables that influenced the community composition. Seasonal variations in hydrological conditions and resource availability were the main factors that influenced the macroinvertebrate dispersal, evaluated considering life-strategy groups. Although the considered ponds and wetlands presented different features, they all contributed to the local ecological network even if they were not all equally interconnected together. All the collected information could be useful to design further possible interventions for conservation aims.