Wonderful Wetlands
Wonderful Wetlands
By Helen
Bain
Wetlands may be the world’s most valuable ecosystems – but they are probably also the most unloved.
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.
We need to learn to love them 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.
World Wetlands Day, which marks the signing of the International Convention on Wetlands in Ramsar, Iran, on 2 February 1971, aims to promote awareness of the global importance of wetlands and the need to protect them.
More than 1400 wetlands worldwide, covering more than 125 million hectares, are recognised under the Ramsar Convention as internationally important wetlands for the conservation of global biodiversity and sustenance of human life.
New Zealand is one of 145 signatories to the Ramsar Convention and has six wetlands with Ramsar status, but this number would be much higher if all our important wetlands were properly recognised. In comparison, Australia has 64 Ramsar sites – even Tasmania alone, with eight sites, outdoes New Zealand.
We should also do more to preserve our remaining
wetlands, because they 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.
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.
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.
Forest & Bird supports recognition under the Ramsar Convention of more wetlands of international ecological significance in New Zealand. Sites where Ramsar status is being sought by Forest & Bird and others include:
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
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
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
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
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, soTe 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 whitebaiting 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.
WhangamarinoWetland
(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
duckshooting.
Farewell Spit
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
ENDS