Wairarapa coastal habitats – Ecological vulnerability assessment Technical Report
- Author
- Roberts, K.L.; Stevens, L.M.; Southwick, M.
- Year
- 2023
- Journal / Source
- Salt Ecology Report
- Publisher / Organisation
- Salt Ecology
- Number
- 108
- Pages
- 136
- Summary
- In response to the National Policy Statement for Freshwater Management (NPSFM), Greater Wellington Regional Council (GWRC) is implementing the Whaitua Implementation Programme (WIP) in five sub-regions (whaitua) across Greater Wellington. The WIP comprises a non-statutory community-led committee that provides advice and direction to GWRC on how best to manage land and water. The Wairarapa coast region is the final sub-region to form a whaitua committee. The committee will achieve a community vision for water by combining mātauranga Māori, citizen science, community knowledge, and science knowledge. To support the whaitua process, Salt Ecology was commissioned by GWRC to visit (April 2022) and synoptically assess the broad scale condition, pressures and vulnerability of 25 estuaries along the Wairarapa coast. An Ecological Vulnerability Assessment (EVA) was applied to the 25 surveyed estuaries, to explore differences between estuaries and support GWRC in prioritising estuaries for management. All the estuaries assessed were sub-tidally dominated tidal river estuaries, with many experiencing stratification and periodic entrance restriction and/or closure. Many of the catchments along the Wairarapa coast are modified for pasture, mainly sheep and beef, and are highly erodible leading to high sediment inputs. To a lesser extent, the estuaries also experience moderate water column nutrient concentrations from both elevated catchment loads and restricted flushing. High sediment and moderate nutrient loads, combined with physical susceptibility (e.g. entrance restriction and/or closure), mean the estuaries on the Wairarapa coast are prone to water quality degradation (e.g. poor clarity, phytoplankton blooms and low dissolved oxygen).