Before European settlement some lowland forest had been burnt by Māori for cultivation or razed by naturally occurring fires, and these areas were covered in scrub. Higher, wetter and less accessible areas were cloaked in podocarp forest, including rimu, tōtara and kahikatea trees. Kahikatea was also common around rivers and lakes.
As the region was developed for agriculture, the lowlands were transformed into pasture. Forests were felled or burned, and swamps were drained.
Gullies are a feature of many Hamilton properties, and until recently they were often undervalued and unkempt. In 2000 the Hamilton City Council started a gully restoration plan, involving the Waikato Regional Council and the University of Waikato’s centres for Continuing Education and Biodiversity and Ecology Research. Enthusiastic property owners and volunteers signed up to plant native species, to beautify the gullies and attract native birds. By 2009 there were 750 landowners on the gully database.
Surviving native vegetation
Most of the forests on the lowlands have been cleared, but there are still groves of kahikatea on the river floodplains in the Waikato basin and the Thames valley. Some of these forest fragments are protected in scenic reserves and on private land covered by Queen Elizabeth II National Trust covenants.
There are healthy populations of endangered pīngao grass in west-coast dunelands, especially around Aotea Spit. Another unique plant species found on the west coast is Hebe awaroa.
Mountains and ranges
Podocarp forest still mantles the mountains and ranges of the region, particularly in the Pirongia Forest Park, and on the Hākarimata Range and Maungatautari mountain. On Pirongia mountain, wood rose (Dactylanthus taylorii), a rare and endangered plant, can be found.
The kauri, a giant forest tree which grows naturally in the northern half of the North Island, reaches its southern limit in the Waikato and is found in the Hākarimata Range, around Pirongia and in the Kaimai Range, where it co-exists with kāmahi, red beech and silver beech at their northern limit – a unique mix of vegetation.
Curse or blessing?
A valued source of food to Māori, Waikato’s wetlands were regarded as a problem to be solved by the first Pākehā settlers. They drained them to create farmland, removing an important habitat for many plant and animal species. By 1976 attitudes had changed and New Zealand became a party to the Ramsar Convention, which seeks to reverse damage to the world’s wetlands. The Ramsar list of internationally significant sites includes the Whangamarino Wetland and the Kopuatai Peat Dome (both listed in 1989).
The region’s peat bogs, such as the Kopuatai Peat Dome, are low-nutrient wetlands, fed by rainwater alone. They are formed from waterlogged plant material which decays very slowly and forms low domes. Rushes are the most common bog plants, which also include sphagnum moss, orchids, sundews, bladderworts, sedges and umbrella ferns.
In contrast, swamps are more fertile as they are fed by nutrient-rich streams and rainwater, and they often flood. Moderately fertile swamps – like those on the margins of peat lakes and bogs south of Hamilton – have plants such as mānuka and sedges. Highly fertile swamps like the Whangamarino Wetland contain raupō, harakeke (swamp flax) and sedges.
There are a number of rare and threatened plants in Waikato wetlands. The swamp helmet orchid (Anzybas carsei), found only in wetlands around Huntly, is classed as nationally critical because it is at serious risk of becoming extinct.
Birds and animals
Before pasture replaced the original vegetation, the Waikato region had a wide range of native birds, reptiles, frogs, insects and snails. Modification of habitats, predation by introduced animals such as rats, feral cats, stoats, ferrets and weasels, and competition from introduced plant species, have greatly reduced their numbers.
Parts of the region are very rich in native birdlife. Lakes, swamps and bogs, especially around the lower reaches of the Waikato River, and the Kopuatai Peat Dome in the Thames valley, are havens for wetland bird species, including crakes, bitterns and fernbirds.
Harbours and estuaries on the west coast, notably Aotea Harbour, are feeding and breeding grounds for large numbers of shorebirds, including migratory wading birds such as godwits. The 3,400-hectare Sanctuary Mountain Maungatautari, a forest restoration project, has built 47 km of fencing so bush birds such as hihi (stitchbird), once common, can survive there again free of predation.
Other animals and insects
Waikato wetlands provide a habitat for the endangered endemic black mudfish.
In the Kaimai Mamaku Forest Park there are small populations of the rare Hochstetter’s frog and the threatened Te Aroha stag beetle.