Limitations of biophysical habitats as biodiversity surrogates in the Hauraki Gulf Marine Park

Abstract

The Hauraki Gulf Marine Park (HGMP) is recognised for its diverse natural environment and associated biodiversity, as well as the extensive social, cultural and economic values derived therein. Here, we evaluate the current level of biodiversity protection provided by existing Marine Protected Areas (MPAs) within the HGMP. We use abiotic datasets to develop a habitat classification system to identify the suite of biophysical habitats found in the Marine Park, and their relative protection within existing MPAs (both no-take marine reserves and Cable Protection Zones). Our analysis demonstrated that half of the biophysical habitats identified in the HGMP are not currently afforded protection within MPAs, and that biophysical classifications poorly differentiate across subtidal, soft-sediment habitats using available data layers. We then evaluated representation of these environmental surrogates within a biodiversity prioritisation analysis based on distribution models for demersal fish species. Biophysical habitat surrogates showed poor representation across habitats within highest-priority areas based on prioritisations of demersal fish biodiversity. This suggests the need for further development of biophysical habitat surrogates that are more strongly correlated with biodiversity, if they are to be used to inform biodiversity protection in the HGMP.