Wetlands are permanently or temporarily wet areas that provide habitats for plants and animals that are specially adapted to wet conditions. Wetlands once covered large parts of New Zealand and in Hawke’s Bay large parts of the flat plains and the valleys were wetlands before they were drained for use as farms, roads and cities.
Wetlands have important functions and many efforts are being made in Hawke’s Bay to protect and enhance existing wetlands, restore those that have been neglected and create new ones.
The main wetlands in Hawke’s Bay are:
Coastal (lagoons & estuaries) - Whakaki Lagoon, Ahuriri Estuary, Tukituki Estuary, Waitangi Estuary, Whakamahi/Whakamahia Lagoons
Freshwater (swamps, lake margins) - Pekapeka, Lake Whatuma, Lake Runanga, Lake Oingo plus the many small wetlands on public and private land.
Why wetlands are important
Wetlands are as they describe – “wet land” – and form a critical boundary between the land and the water. In Hawke’s Bay we have examples of many types of wetlands. The types of plants and animals found in wetlands vary depending on whether it is coastal or inland freshwater, how much water flows in and out, how long it stays there, how deep the water is, how warm it gets and what nutrients and sediment are in it.
Wetlands are important because they:
- are culturally valued, as Maori regard these places as taonga, of great significance. They once contained many wahi tapu sites, and any work in these areas still needs guidance on their historical protection. Wetlands can still be food sources and once were transport corridors, provided building supplies and contained many pa sites.
- store floodwaters – just like giant sponges, wetland plants slow the flow of water off the land, soak up excess floodwater, and then slowly release it to maintain summer water flows in streams.
- improve water quality - the plants trap sediment suspended in water, making the water cleaner. Alongside rivers, roots hold bank soils together, reducing erosion and further sediment entering water. Bacteria living in wetland soils absorb and break down nitrogen from farm run-off and leaching, improving water quality. Wetland plants absorb many nutrients.
- are habitats for a diverse range of plants and animals, many of them rare and threatened species. Wetlands can be important breeding sites and nurseries for young fish and birds.
- are sinks for excess carbon, implicated in potential global warming, especially peaty wetlands like Lake Poukawa.
What we are doing about wetlands in Hawke’s Bay
Volunteers - It’s exciting that in Hawke’s Bay, many hundreds of people care about wetlands and volunteer to help dig, plant and weed wetlands. We could not restore these ecological areas without their valued help! Many people continue to monitor changes in their wetland projects, and form permanent care groups, such as at Whangawehi at Mahia LINK to their website.
Farmers - Many farmers have fenced off and planted wetlands on their properties, either through their own initiative or by making use of HBRC advice and financial support for these projects through the Regional Landcare Scheme. In the last 10 years, we have assisted over 140 individual landowners or groups in around 190 wetland restoration or enhancement projects.
HBRC has an important monitoring and research role. We have begun a state of the environment programme for freshwater wetlands in the Tukituki Catchment as a pilot area. We are collecting ecological information so that the region better understands the flora and fauna, nutrient status and hydrology of these areas. We also monitor the larger wetlands and lakes
HBRC has enhancement and maintenance programmes for wetlands for which we have responsibility at Tutira, Pekapeka, Taipo, and Waitangi.
In 2018 Hawke’s Bay Regional Council will be hosting the National Wetland Restoration Symposia. Experts from around the world and the country will converge in Napier for this event.
There is more information on types of wetlands and restoration on the National Wetland Trust of NZ pages.