Working Group on Biodiversity Science (WGBIODIV) aims to develop the scientific understand-ing of processes supporting marine biodiversity and provide evidence of change in biodiversity patterns through space and time.
The group progressed work in relation to three objectives: (1) testing an indicator that captures the response of benthic communities to fishing pressure and exploring its effectiveness in both the North Sea and Bay of Biscay; (2) investigating predator and prey interactions structuring trophic guilds and ecosystems; (3) examining the efficacy of spatial management measures as means of maintaining marine biodiversity.
WGBIODIVs benthic indicator work demonstrated that a suite of biological traits related to sen-sitivity to, and recoverability from trawling were functionally independent for trawled communi-ties of endo-benthos in the North Sea and epibenthos from the Bay of Biscay. Biological traits can be used to understand the changing status of benthic communities over short and long time scales (relative to the species life-span). Benthic diversity also changes spatially and the spatial scale is important to consider in relation to conservation and management. For example, biodi-versity ‘hotspots’ differ in location and environmental conditions depending on whether α-, ß- or γ-diversity is studied. Both the environment and anthropogenic influences can stress benthic communities and we demonstrate that cumulative effects can exceed thresholds, leading to structural change in ecosystems. To capture change in trophic guilds, we developed an indicator, based on ICES year of the stomach and Cefas DAPSTOM records that can aggregate predators by commonality in their diets. Combined ICES coordinated surveys, spatial change in feeding guild biomass can be monitored over time and inform on change in food web function and im-pacts by fisheries and environmental change. Multi-species food web modelling demonstrated that fish stocks within feeding guilds become at risk of depletion as primary production of phy-toplankton diminishes, with planktivores most sensitive to this risk and piscivores least sensi-tive. Where risks to benthic communities, mobile species and food web function exist, spatial protection from trawling and other pressures may be appropriate. We show that currently there is little overlap between the core areas of sensitive demersal fish and the Natura 2000 network of MPAs, since these were typically designated to protect habitats, seabirds and marine mam-mals, and even less overlap between core areas of these species and offshore windfarms. Never-theless, further fisheries management within MPAs could provide rewards for some species in some areas: e.g. for lump sucker, cod, brill and spurdog in the Skagerrak/Kattegat and for thorn-back ray and tope off the southeast coast off England.
Future work aims to: develop a multidimensional perspective of biodiversity change (e.g. trait and taxonomic diversity in their alpha, beta and gamma forms); identify thresholds responses of biota and ecosystem structure to highlight areas where marine biodiversity is at risk; further examine the efficacy of spatial exclusions to protect biodiversity and support ecosystem services.