Ecosystem damage from anthropogenic seabed disturbance: A life cycle impact assessment characterisation model

Despite the high amount of pressure placed on benthic habitats by anthropogenic activities, particularly in coastal shelf areas, as yet, the impact of seabed damaging activities on ecosystem quality has not been included in Life Cycle Assessment (LCA). We present a globally applicable impact characterisation approach, parameterized within 17 marine ecoregions in Europe. Our modelling approach includes two perspectives: the single-impact perspective and the repeated-impact perspective. The approach for the single-impact perspective is a function of the spatio-temporal scale and intensity of the anthropogenic disturbance, the initial benthic response, and an estimated ecological recovery period. The approach for the repeated-impact perspective additionally accounts for the industry-specific interval between disturbance events, allowing for consideration of potentially incomplete ecological recovery between disturbance events and therefore the potential for both recoverable and non-recoverable potential impacts. We exemplify the repeated-impact perspective for the benthic trawl fishing industry in Europe. Analogous to current approaches for characterizing land use impacts in LCA, we quantify characterisation factors (CFs) for both occupation and transformation impacts. CFs for occupation impacts are ecoregion-specific. CFs for transformation impacts are spatially differentiated at the resolution of seabed substrate type, categories of hydrodynamic energy, i.e. water movement due to the influence of waves and currents, fisheries management zone (repeated-impact perspective only) and marine ecoregion. We estimate ecological recovery times with consideration of the influence of seabed substrate type, hydrodynamic energy at the seabed and the stock of potential recolonizers. The characterisation factors allow for quantifying indicators of ecosystem damage from seabed disturbance in terms of a time-integrated relative species loss. With a single-impact perspective, the largest impact intensities are found in areas with the longest estimated ecological recovery time. In the repeated-impact perspective, the largest intensity of time-integrated non-recoverable impact occurs when the disturbance interval is equal to half the ecological recovery time.