Optimization of aquatic macroinvertebrates sampling methodology in rice fields of Albufera Natural Park (Valencia, Spain)

Abstract

The Albufera Natural Park (PNA) is one of the most important wetlands in the western Mediterranean. It consists in a coastal shallow lake surrounded by a wide extension of rice fields (21000 ha total area) separated from the sea by a sand levee (30 km), with dunar systems. This protected area is included in the list of wetlands of international interest of the RAMSAR convention and the Red Natura 2000, as a site of Community Importance, and Special Protection Area for birds. It presents an important bird community with 250 species, most of them with a diet based, to great extent, on benthic aquatic macroinvertebrates. In aquatic environments relationships between the macroinvertebrate communities and water quality has been widely demonstrated. The use of these organisms is an essential tool in ecological studies in aquatic systems, but a great effort is needed, because of the sample processing and the species determination. For this, it is essential to find a balance between sampling effort and the significance of the results. In this communication we revise a sampling metodology to evaluate accurately the macroinvertebrate benthonic community by means of the optimization of the sampling effort, to be applied in monitoring of water quality or other ecological studies. This procedure focuses on determining the minimum number of samples giving significant results in studies of aquatic macroinvertebrates carried out in rice fields; environments where most of the birds in the Albufera Natural Park obtain their food supplies.