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Clark DE, Stephenson F, Hewitt JE, Ellis JI, Zaiko A, Berthelsen A, Bulmer RH, Pilditch CA
Influence of land-derived stressors and environmental variability on compositional turnover and diversity of estuarine benthic communities
It can be challenging to differentiate ecological changes caused by human activities from those generated by natural background variability. Clark and co-authors demonstrate that both human-influenced land-derived stressors (sedimentation and nutrients) and natural environmental variables (sea surface temperature, wind-wave exposure, Southern Oscillation Index) are important predictors of benthic community compositional turnover in New Zealand estuaries. Despite the range of factors influencing turnover, the negative effects of land-derived stressors could be disentangled from natural environmental variability. Critical stressor levels associated with high rates of turnover were identified, providing a useful contribution on thresholds associated with land-derived stressor effects. This study enables a move towards ecosystem-based management, which is widely accepted the best approach for managing complex interactions in marine ecosystems. These complex interactions include how land-derived stressors cumulatively influence estuarine health, against a background of natural variability operating across multiple spatio-temporal scales.