Macroinvertebrates colonization and evolution in the WWF protected area “La Francesa" (Pianura Padana, Italy): a new man-made pond.

The WWF protected area “La Francesa”, established in 2005 in the province of Modena (Emilia-Romagna, Italy), is one of the few areas of natural interest in the low lands of the province. Originally, it was a land of 23 ha used for agricultural purposes, set aside because of its low productivity. From the beginnings of the ‘90s, it has been managed in order to recover its naturalness with the planting of native species and, at the end of 2005, a new man-made pond of 8 ha was created to increase its natural value and the variety of the ecosystem. The present study shows the result of two monitoring surveys carried out during summer 2006 and 2011 to assess the colonization status, and its variation along time, of the macrozoobenthic community of the pond. Samplings were performed with an Ekman bottom grab sampler and a standardized net in six different stations. Results showed a temporal shift in species composition due to changes in the habitat, specifically the development of hydrophytic vegetation along the shore favoured by the stabilization of the system, and the spread of the exotic plant Ludwigia peploides that covered the wet meadow of the pond.