A General-Purpose Biotic Index to Measure Changes in Benthic Habitat Quality across Several Pressure Gradients

Realistic assessments of the ecological status benthic habitats, as requested by European directives such Water Framework Directive and Marine Strategy Directive, require biotic indices capable detecting anthropogenic impact without having preliminary knowledge occurring pressures. In this context, a new general-purpose index (GPBI) based on deviation macrofauna community composition structure from valid reference (i.e., good status) is proposed. GPBI assumption that site becomes impacted pressure, most sensitive species are first to disappear, stronger impacts lead more important losses. Thus, it explicitly uses within-species loss individuals in tested station comparison one or several stations basis assessment. study, successfully used four case studies considering diversified pressures fauna: (1) maerl extraction northern Bay Biscay, (2–3) dredging trawling North Sea, (4) hypoxic events at seafloor Gullmarfjord. Our results show was able efficiently detect different physical disturbances well hypoxia performs better than commonly pressure-specific (M-AMBI TDI). Signal detection theory propose sound good/moderate quality boundary, recommendations for future monitoring also provided reported performance GPBI.