Genera as proxies for species α- and β-diversity: tested across a deep-water Atlantic–Arctic boundary



The deep-sea floor is increasingly subject to anthropogenic impacts. Consequently, there are increasing efforts to develop appropriate management strategies. Species-level indicators and assessments are hampered in the deep sea by the high proportion of unknown species routinely encountered. If environmental management is to keep pace with exploitation, alternative approaches including higher taxon surrogacy (taxonomic sufficiency) must be considered. Here we compare genus- and species-level studies of the diversity and ecology of deep-sea macrobenthos on the West Shetland Slope (NE Atlantic). This is an environmentally complex region that encompasses a biogeographic transition from temperate North Atlantic to Arctic conditions, and so may be particularly challenging for any general relationship between species- and genus-level analyses. We ask two questions: (i) does genus diversity reflect species diversity and (ii) does genus-level ecology reflect species-level ecology? We conclude that among the West Shetland Slope macrobenthos: (i) genus-level α- and β-diversity measures are highly correlated with and good predictors of their species-level equivalents and (ii) that their ecology is very well described by genus-level data. We further note that, given the complexity of the West Shetland Slope environment, it may be reasonable to expect these conclusions to hold in other deep-sea environments.