Nelson Lakes National Park was formed in 1956 as the ninth national park in New Zealand.

Specific references for this page: Gerald Cubitt and Les Molloy 1994: Wild New Zealand. New Holland. Craig Potton 1998: National Parks of New Zealand. Craig Potton Publishing. The Story of Nelson Lakes National Park 1984. Nelson Lakes National Park. Wild New Zealand 1981. Reader's Digest New Zealand National Parks, 1979. Collins Nature Heritage Series. Robbie Burton & Maggie Atkinson 1998: A Tramper's Guide to New Zealand National Parks. Reed John Kent 1998: South Island Trout Fishing Guide. Reed. John Cobb 1990: The Walking Tracks of New Zealand's National Parks. Viking.

The inclusion of the Glenroy and Matakitaki Valleys in 1983 was the largest of several additions since its creation. This is a mountainous area of long ranges separated by deeply gouged and densely forested valleys. Many other features left from the last glacial period remain in the landscape, like the two lakes (Rotoroa and Rotoiti) after which the park is named. While Nelson Lakes National park has a good network of tracks and huts, it will also meet the expectations of those in search of wilderness and remoteness.
See below: Activities - What to see and do in Nelson Lakes National Park

Geological setting
Nelson Lakes National Park is located in the northern part of the Southern Alps. Its north-western boundary follows the Alpine Fault (apart from the bulge of Lake Rotoroa). The path of the fault is clearly shown in several little valleys (Station Creek, Bulls Creek), and by the markedly higher altitudes immediately to its south-east.
The mountains of the park are almost entirely made of the two main rock types of the Southern Alps: greywacke and argillites (Torlesse Supergroup) in the St Arnaud and Travers ranges, schists of the Haast Schist Group in the Misery and Ella ranges. A variety of older rocks of volcanic, intrusive and sedimentary origins are found immediately west of the Alpine Fault.
No glaciers exist at present in the park, but the landscape was intensely sculpted by the glaciers of the latest ice ages. Many glacial landforms remain, such as lakes Rotoiti and Rotoroa, the moraine on which St Arnaud is located, cirques like Cupola Basin, and many others.
See also:
the Rocks of the New Zealand mountains
the Southern Alps,
Active faults in New Zealand

Climatic conditions
The ranges to the west of Nelson Lakes National Park provide shelter against the prevailing westerly weather systems, so that climatic condition in the park are less severe than elsewhere in the Southern Alps.
Precipitation is higher in the western parts, and decreases eastward: 1800 mm/year (71 in.) at Lake Rotoroa, 1550 mm/year (61 in.) at Lake Rotoiti. Likewise, over 4000 mm/year (157 in.) on the tops of the Emily Ranges in the west, 2500 mm (98 in.) further east in the St Arnaud Range. Precipitation decreases even more further east, as can be seen in the dry lands that stretch towards the Kaikoura Ranges.
Temperatures are mild and vary within a narrow range between winter and summer: at Lake Rotoiti 600 m (1968') above sea level mean summer temperature is 15 degrees C (with highs up to 30 degrees C), and mean winter temperature is 4 degrees C (with lows down to -10 degrees C).
The weather in the park is changeable and difficult to predict, due mainly to the often quick succession of cold and warm fronts brought by the westerly weather system, as well as the local disturbances generated by the mountains.
See also: Climatic influences in the New Zealand mountains

Forests
Beech forests dominate the lower landscape of Nelson Lakes National Park. Podocarp forest, mixed with beech, is restricted to the lower and wetter areas around Lake Rotoroa. Major species present are kahikatea, miro, matai, rimu.
All four species of beech are present. Red beech and silver beech share the lower, warmer and more fertile areas, with hard beech less common, in the less fertile areas. Mountain beech and silver beech extend up to the treeline, at about 1400 m (4590') above sea level.
The treeline is itself a striking feature in the park, as it stretches in straight line, as if drawn artificially, along the valley sides.

Vegetation above the bushline
  The alpine scrub zone immediately above the treeline is patchy in the park, because it has often been destroyed by fire or grazing. Dracophyllum, celery pine, snow totara (Podocarpus nivalis), mountain flax, can be found in some areas.
Snow tussock (Chinochloa) grasslands dominate the rest of the vegetation above this shrubland, with four main species: C. pallens, C. flavescens, C. rubra and C. australis.
  Interspersed among them are many other species of alpine plants, such as spaniards (Aciphylla), mountain daisies (Celmisia), mountain buttercups (Ranunculus), gentians, Ourisia, Senecio.
  Vegetation is sparse above 1700 m (5577'), though various species of vegetable sheep thrive, and South Island edelweiss, gentians and hebes grow in sheltered spots.

Birds
 Beech forests are not rich in flowers or nectar, and so provide habitats mostly to insectivorous birds.
In Nelson Lakes National Park many insects feed on the honeydew secreted by a scale insect living off the sap of trees. In turn they provide food for birds such as fantails and tomtits. The honeydew is also a source of sugar appreciated by birds, especially in winter.
Birds of the beech forests include robins, riflemen, silvereyes, grey warblers, tuis and bellbirds. Kakas and parakeets also feed on insects, kakas in particular using their sharp beak to rip the bark off trees and dig out larvae.

Native New Zealand pigeons are especially attracted to the podocarp forests, where they feed on the fruits of miro and kahikatea, and on the nectar of the flowers of the kowhai.

Harriers, New Zealand falcons and moreporks (the native owl) can be seen or heard throughout the park.

Above the bush line, Nelson Lakes National Park is home to the rock wren, the only truly alpine bird in New Zealand. Keas and pipits are also commonly found in that zone.

The park's lakes and streams provide habitat for many aquatic birds. Paradise shelducks and native grey ducks are common. By contrast the numbers of New Zealand scaup have dwindled, like those of the endangered blue duck which has been driven to the most remote alpine streams.
The lakes and main rivers are home to shags, herons, gulls and kingfishers. They are joined in summer by migrants such as South Island pied oystercatchers, pied stilts, banded dotterels, spur-winged plovers.

Other native fauna
  There are many species of invertebrates in the park: native wasp, spiders, moths, butterflies, weevils, wetas. The beech forests sustain several species of defoliators and wood borers, such as the mountain beech moth caterpillar Proteodes canifex, the beetle Nascioides enysi, and the three species of Platypus pinhole borers.
  Above the bushline there is an abundance of grasshoppers.
  In the waters of the lakes live native eels (Anguilla diffenbachii) and several species of galaxiid fish (the whitebait family), including G. divergens and G. brevipinnis.

Honeydew
  Honeydew is the product of the small female sooty beech scale insect, Ultracoelostoma assimile. This insect lives inside the bark of trees, protected in a waxy cuticle. It feeds on the sapwood, and sends out its sugary byproducts via a long thin translucid tube protruding out of the bark. In the beech forests the trees are covered by multitudes of such tubes with their sweet droplets, on which depend the lives of many species of insects and birds.
 
Introduced animals
  Rats, mice, opossums, stoats and in some areas pigs live in the forest.
Red deer, chamois and hares live above the tree line.
As elsewhere in New Zealand introduced animals have had a destructive impact on the indigenous flora and fauna.
   The numbers of red deer and chamois were drastically reduced in the past decades and remain under control.
  On the estern side of Lake Rotoiti, near St Arnaud, the Department of Conservation is managing the Rotoiti Nature Restoration Project, a special area where all exotic predators are removed, in order to restore a healthy native fauna and flora.
See also Mainland islands

Activities - What to see and do in Nelson Lakes National Park

Tramping
Nelson Lakes National Park is especially well suited for tramping.

Travers Saddle (1787 m/5863') and the south face of Mt Travers (2338 m/7670'). At the southern end of Travers Valley, Travers Saddle provides easy passage into the Sabine Valley, on one of the favourite tramping circuits in the park. The south face of Mt Travers is one of the sustained climbs in Nelson Lakes National Park. Photo NC.

The park is well equipped with huts, tracks and bridges, yet offers untracked and more remote valleys for those seeking greater challenge or isolation. The climate is moderate by comparison with other areas in the Southern Alps. And with its long forested valleys, high passes, large areas above the bush line, lakes and tarns, the landscape is both varied and well adapted to tramping. The Travers-Sabine circuit offers a good combination of these features and reaches deep into the wilderness of the park. It is walked in a minimum of 4 days but can be extended by a number of side trips to side valleys, mountain cirques, lakes and tarns.

Short walks
There are a variety of short and day walks available from St Arnaud and from Lake Rotoroa. They offer the possibility to quickly discover many interesting features of the park, including the lakes, beech and podocarp forests, native birds and wildlife, native plants, remnants of the ice ages such as moraines and roches moutonnees, and some alpine areas above the bush line.

Native plants and wildlife discovery
At St Arnaud on the edge of Lake Rotoiti the Department of Conservation manages the Rotoiti Nature Recovery Project. This is an area of 825 hectares (1700 acres) where introduced predators are removed and native plants and animals can re-establish themselves. Two short walks allow visitors to enjoy the forest and see some of these native plant and animal species.

Mountaineering
While Nelson Lakes National Park does not count among the major climbing areas in New Zealand, its many 2000 metre-plus (6562') peaks offer many ridges, couloirs, buttresses and short steep pitches with various degrees of difficulty. Most of them have recognised routes.

Fishing
Both lakes Rotoiti and Rotoroa, as well as the major rivers of the park, offer excellent opportunities for fishing brown trout, more rarely rainbow trout (in Lake Rotoroa and the Sabine River).

Hunting
The main game species in the park are chamois and red deer, and hunting them is encouraged.