A comparison of macroinvertebrate and diatom responses to anthropogenic stress in small sized volcanic siliceous streams of Central Italy (Mediterranean Ecoregion)

In addition, the ecological status of volcanic streams was evaluated by means of the two Intercalibration Common Metrics Indices (ICMi), based, respectively, on macroinvertebrate and diatom communities. The two ICM indices, developed for the Italian biomonitoring program (sensu WFD), were strongly correlated and provided a final classification mainly related to the water quality (nutrient enrichment and organic pollution). However, both indices were less sensitive to the hydromorphological alterations, highlighting the need for the development of stressor specific indices to achieve a complete evaluation of the anthropogenic stress present in the area. Studies of this kind across different disturbance gradients and focused on a particular river type (e.g. Mediterranean small-size volcanic-siliceous streams), will enable the relative merits of the indicators to become apparent and greatly facilitate their appropriate application.