Wetlands may be the world’s most valuable ecosystems – but they are probably also the most unloved.
Wetlands – Fact Box
- Wetlands are one of New Zealand’s most important habitats but have almost been wiped out in the last 200 years – fewer than 10% of our wetlands remain and this destruction continues.
- In Auckland wetlands once covered large expanses of low-lying country, but today less than 0.4% remains as wetlands. Te Henga Swamp, Auckland’s largest and most superb remaining wetland is especially precious
- Six of New Zealand’s wetlands have Ramsar protection status.
- World Wetland Day is held on Feb 2 each year.
Featured photo: Wynston Cooper
Often under-appreciated as mere bogs or swamps to be drained and developed, wetlands are among the most economically and ecologically valuable ecosystems on Earth.
They can also be an attractive feature of a lifestyle block, help improve water quality on your property, and provide a haven for native plants, birds, fish and other animal life that is found only in wetlands.
We need to learn to love wetlands and look after them better if we want to preserve the rich plant and animal life they support, and sustain the range of valuable services they provide for the survival of our planet and human life.
The vast majority of New Zealand’s original wetlands have already been destroyed, but there is much we can do to preserve those that remain. Lifestyle block owners in particular can help by preserving or creating their own wetlands.
Wetlands are valuable for a number of reasons of which most people aren’t even aware. The “services” wetlands provide include:
- storing and purifying water
- providing flood control, stabilising shorelines and protecting against storms
- replenishing groundwater
- providing nurseries and habitat for native fish, including eels and whitebait
- supporting a wide range of native plants, including many threatened species
- retaining nutrients and sediments
- supporting biological diversity
- reducing erosion and nutrient run-off
- providing nesting and feeding areas for birdlife, including many migrating birds that visit New Zealand each year, and many endangered bird species (wetlands are home to 22% of New Zealand’s birds)
- storing carbon and mitigating effects of climate change
- creating tourism and recreation opportunities (for example for bird watchers, walkers, photographers, fishermen, whitebaiters and hunters).
Wetlands are highly sensitive ecosystems, threatened globally and in New Zealand by draining and reclamation for agriculture, building and other development, invasive plant and animal pests, pollution and damage from livestock.
Responsible riparian management can protect our remaining wetlands through appropriate planting, fencing to exclude stock, reducing pollution and nutrient run-off going into wetlands, responsible recreational use, pest control, and preventing further loss of wetlands through draining and development.
The Ramsar convention signed in 1971 provides a framework for national action and international cooperation for the conservation and wise use of wetlands and their resources. Below are some of the wetlands that Forest & Bird is seeking Ramsar protection.
Wairau River and Lagoons
The Wairau River is one of the most intact and extensive examples of a braided river system in New Zealand. The river, lagoons and wetlands are home to 90 species of wetland bird, 22 of New Zealand’s 42 native fish species and a number of threatened wetland plants. It is also popular for recreation, including fishing, whitebaiting, birdwatching, duckshooting and kayaking.
A proposal by TrustPower to build a hydro-electric power station on the Wairau and divert much of the river’s flow through a 50km canal threatens the river and wetlands and the diverse plant and animal life there.
Kaipara Harbour is the largest harbour in the Southern Hemisphere. It includes sites of high ecological importance, such as marine habitats, wetlands and salt marsh in areas such as Manukapua (Big Sand Island), Papakanui Spit, Waionui Inlet and Omokoiti. More than 30,000 birds inhabit Kaipara Harbour each year and it is an important destination on the “East-Asian Flyway” used by waders migrating between Northern and Southern Hemispheres. Kaipara remains threatened by activities such as sand mining and aquaculture, which can damage vulnerable wetland habitats and wildlife when carried out in inappropriate sites or without adequate environmental protection.
Ramsar status will not lock up Kaipara’s resources but will encourage sustainable development that does not compromise its valuable natural heritage.
Ohiwa Harbour in the Bay Of Plenty is an internationally significant harbour of sandspits, islands, marshlands, tidal flats and mangrove forests. It is an important habitat for migrant birds and endangered shore birds – around 80 species in total. Numbers of migrant Eastern bar-tailed godwits and Pacific golden plovers peak at more than 5000 in summer. They leave for the Northern Hemisphere in April and an annual “Birds-a-Plenty festival welcomes them back in October. The harbour covers nearly 2400ha of sheltered tidal water protected from the open sea by Ohope and Ohiwa Spits.
Lake Wairarapa, surrounding wetlands (in particular Boggy Pond and Matthews Lagoon) Lake Ferry/Onoke and the 5km Onoke Spit, are internationally recognised sites for rare birdlife and are home to 96 bird species, and a dozen native fish species and nationally rare and threatened plants are also found here.
The eastern shore of Lake Wairarapa is also an important habitat for native turf plant communities. Lake Wairarapa and Onoke are also widely used for recreation, including fishing, windsurfing, boating, walking, whitebaiting, birdwatching and duckshooting. The area is also one of the oldest sites of pre-European Maori settlement, with evidence of occupation dating back to the 12th Century.
Mangarakau Swamp, just below Farewell Spit in north-west Nelson, is the largest remaining wetland in the Nelson-Marlborough region. The swamp, including Whanganui Inlet and Lake Otuhie, covers about thousands of hectares. The swamp is valued for biitern, fernbird and endemic mudfish that are found only at Mangarakau, and the inlet has the greatest variety of invertebrates of any estuary in New Zealand, while Lake Otuhie provides valuable habitat for giant kokopu and eel. The site is bounded by Kahurangi National Park and Te Tai Tapu marine reserve.
Te Henga Swamp
In Auckland wetlands once covered large expanses of low-lying country, but today less than 0.4% remains as wetlands, so Te Henga Swamp, Auckland’s largest and most superb remaining wetland is especially precious.
Formed out of the Waitakere Stream, the large marshland is considered one of the finest botanic areas in Auckland and is rich with unusual species, such as the carnivorous, pale yellow bladderwort. Birds found here include banded rail, spotless crake, marsh crake, brown bittern, fernbirds and grey duck.
New Zealand Wetlands with existing Ramsar Status
Manawatu River Mouth and Estuary
Listed in 1995, the 200ha estuary is the largest estuary in the southern half of the North Island. It is home to a diverse range of birds (93 species have been recorded here) and supports a number of threatened New Zealand native species – 13 bird species, six fish species and four plant species. It is also a popular fishing and white-baiting location and has archaeological and cultural significance as site of early “moa hunter” settlements.
Firth of Thames
The 7800ha site is an important feeding ground for up to 25,000 birds at any one time, most of them migratory, and is one of New Zealand’s three most important coastal stretches for wading birds. 74 shorebird species have been recorded here, including many rare or uncommon species. The area is also used for commercial and recreational fishing and gamebird shooting.
Kopuatai Peat Dome (Hauraki Plains)
Listed in 1989, the 9665ha site is the largest raised or domed bog in New Zealand and the last example of its kind that remains intact. It supports vegetation unique in New Zealand and is an important habitat for native fish and eels. 54 bird species have been recorded here. The area is also used for whitebaiting and duckshooting.
Whangamarino Wetland (Waikato)
The second largest bog and swamp complex in the North Island, at 5690ha, the Whangamarino Wetland is home to 239 wetland plant species, including many rare and vulnerable species. It is a notable water bird habitat, has abundant native fish, plays a significant role in flood control and is a popular location for fishing and duck-shooting.
Farewell Spit was listed in 1976 and comprises 1961ha plus another 9427ha on intertidal zone. The 30km-long spit, tidal mudflats and saltmarsh provide important feeding areas for a large number of wetland birds (more than 90 species) including rare and threatened species. Its sand dunes support a diverse and unusual plant community, including endangered species.
Waituna Lagoon (Southland)
Covering 3556ha, Waituna Lagoon was listed in 1976 and is home to at least 76 bird species and more than 150 native plant species among its unique, moor-like vegetation. It is an important summer refuge and feeding area for many migratory wading birds. It is also an important trout fishery and native fish habitat.
You can read the full Ramsar factsheet on each of these wetlands at www.wetlands.org/rsis