Research Aim 4 – Ecological indicators for Estuaries
- We have compiled the first national estuary monitoring dataset for New Zealand. It represents a significant resource for estuary management and research and contains information from 815 sampling events, over 15 years, across 70 estuaries and 14 councils. Berthelsen et al. (2018). National Estuary Dataset: User Manual.
- The National Estuary Dataset was used to summarise a broad range of estuary indicators for New Zealand to help managers to place the health of their estuary in a national context. Berthelsen et al. (2019). New Zealand estuary benthic health indicators summarised nationally and by estuary type.
- We investigated the suitability of nine biotic indices for assessing estuary health in New Zealand to provide guidance on which indicators councils should be using to assess health with the view to developing a standardized approach for estuary health monitoring. Berthelsen et al. (2018). Relationships between biotic indices, multiple stressors and natural variability in New Zealand estuaries.
- We developed a sensitive and standardized approach to assessing estuarine health in response to sedimentation and metal loading. This tool enables estuary health to be compared in a consistent manner across New Zealand and the approach can be applied to other stressors or countries. Clark et al. (in press). The development of a national approach to monitoring estuarine health based on multivariate analysis. Marine Pollution Bulletin.
- The usefulness of estuary monitoring data is currently hampered by inconsistencies in sampling protocols and methods. We identified inconsistencies in the methods councils currently use to monitor their estuaries to help councils to standardise their data collection. Berthelsen et al. (2017). National Estuary Dataset: inconsistencies in survey data.
- As a first step towards setting ecological health thresholds in streams that also protect estuaries, we are exploring whether stream ecological health relates to the ecological health of receiving estuaries across New Zealand. Berthelsen et al. (in prep.) Relationships in ecological health between connected stream and estuary ecosystems.
- We are exploring the suitability of assemblage thresholds to inform estuary management. In particular, we want to know if the response of macrofaunal communities to increasing sedimentation and nutrient loading is linear or shows threshold changes. We aim to characterise where those threshold changes occur and the types of community changes you would expect to see (e.g. loss of shellfish). Clark et al. (in prep).