Integrating rapid habitat mapping with community metrics and functional traits to assess estuarine ecological conditions: A New Zealand case study

Estuarine ecosystems are under pressure from anthropogenic stressors in many parts of the world. In a New Zealand estuary, we integrated rapid habitat mapping, univariate and multivariate benthic community metrics and functional traits-based metrics to provide a holistic assessment of its ecological condition. Our integrative approach identified 11 different habitat classes across the study estuary and revealed how univariate, multivariate, and functional traits-based metrics varied spatially. Variation was driven mainly by sedimentary conditions, particularly, the sediment's organic matter and silt-clay content. Degraded conditions were apparent in several parts of the estuary, which overlapped with areas showing high concentrations of decaying algae, anoxic conditions, and low values of univariate and functional metrics. Our holistic approach, integrating mapping and quantitative community assessments, provided a more complete picture of estuarine conditions and enabled us to identify locations across the estuary with the greatest potential for restoration success.