Environment > Wetlands Life

At first glance, a wetland may not look very interesting, but don’t be fooled! Wetlands are one of the most diverse habitats to be found in New Zealand, home to an amazing range of plants and animals.

Just take rushes and sedges, for example. These wetland plants look so much alike that its hard to believe there are 47 species (16 native) of the Juncus species of rush and 94 species (73 of which are native) of Carex, the most recognisable of the sedges. Most of these are found in wetlands.

The importance of wetland habitat for birds is well illustrated by Lake Ellesmere (Waihora) in Canterbury, where 149 bird species (47 per cent of all New Zealand’s mainland and island species) have been recorded.

Not Just Swamps

Wetlands are not just swamps. They include a variety of habitats ranging from large lakes to ponds, swamps, peatlands and bogs, slow streams, pakihi wetlands, lagoons and estuaries. They also include ditches, water races, mining pits and hydro lakes.

Wildlife

Its hard to imagine wetlands without the ducks, swans and other waterfowl that congregate there. Black and mute swans, scaup and some duck species like shoveller prefer the open water, while grey duck, mallards and grey teal frequent both open and sheltered waters. Wetland margins provide nesting sites for all species. Canada geese and paradise shelduck rest and nest in the margins, but graze on nearby pasture.

Wetlands are vital habitat for many other birds. Grebes and shags prefer open water while herons and waders such as stilts and oystercatchers feed in the shallows. Rails, bitterns and fernbirds are found in the emergent vegetation of the margins. These species breed in New Zealand and some, such as crested grebes, bitterns and rails are totally dependent on wetlands for their survival.

Visitors

Many of our wetland visitors are international travellers. Arctic waders and terns migrate south after breeding to winter in the southern hemisphere. Tens of thousands of godwits, sandpipers and others visit New Zealand’s wetlands and estuaries each year.

Native Fish

Deep swamps surrounded by thick flax, raupo and willows, their margins thick with water weeds, with soft edges and bottoms and deep, dark water conceal secretive and mysterious fish. Very little is known about many of these species, some of which are rare and endangered. They include the relatively common shortfinned eel, mudfish, whitebait and kokopu. Even some predominantly rocky stream dwellers such as giant and redfinned bullies and torrentfish are sometimes found in swamps. Koaro and lampreys travel through these wetlands to spawning areas and native freshwater flounder are to be found in some lowland areas.

Protection Is Vital

Complex relationships exist between all swamp species. Although changes may not directly affect one species, less obvious indirect effects may be involved through food chains. What is certain is that it is vital that New Zealand protects the wetland habitats it still has.

Only by doing this can we ensure the ongoing conservation of rare native birds and fish and the breeding of waterfowl, eels and whitebait in large enough numbers to sustain recreational hunting , the distinctive whitebait fishery and the valued wild commercial eel fishery.