Assessment of the effects of check-dams on riparian vegetation in the mediterranean environment: A methodological approach and example application

The paper illustrates some criteria for the assessment of the direct effects of check-dams on riparian vegetation. The paper develops a methodology to investigate such effects, which requires the preliminary identification of homogeneous torrent reaches in which a sample of existing check-dams is identified for study. Transects, subdivided into sample areas, are located immediately upstream and downstream of check-dams and in control zones. At these transects vegetation parameters (number of species, canopy cover of each species and vegetation layer, height of each vegetation layers, vegetation type, biological forms and ecological groups) are surveyed. Two new parameters (global canopy cover and weighted canopy height) are proposed to give synthetic information on the global development of vegetation. The features of transects close to check-dams are compared with those of control transects. The methodology is applied to two calabrian torrents. An influence of check-dams is found especially in the lower torrent reaches, with a longitudinal diversification of vegetation types and the creation, either immediately up or downstream, of habitats characterized by new biological and ecological formations.