Purakaunui Falls, New Zealand Photograph by Susanne Peck   Southern part of New Zealand's South Island Temperate Broadleaf and Mixed Forests   4,500 square miles (11,700 square kilometers) -- about the size of Connecticut Vulnerable

· Location and General Description
· Biodiversity Features
· Current Status
· Threats
· Ecoregion Justification
· References
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Covering the southeastern tip of New Zealand’s South Island, much of the Southland region is modified and large areas are intensively farmed. However, there are still significant coastal wetlands and upland areas of beech forest and tussock grasslands. The Eyre Mountains support distinctive local endemic plant species and the Catlins National Park contains an outstanding range of habitats, from coastal habitat to alpine bogs. A number of protected areas are found in the region, but lowland and grassland communities are underrepresented in conservation reserves and logging, clearing for development, and introduced animals are threats.

Location and General Description

Located at the southernmost extreme end of South Island, Southland consists of coastal lowlands separated from dry central plains by the hills of the Hokonui Syncline. Rainfall on the damp coastal lowlands ranges between 900 mm to 1,600 mm per annum, while the relatively dry central plains receive annual rainfall from 700 mm to 900 mm. Further north there a band of high, forested mountains run along the boundary with Otago. The Te Anau Basin in the northeastern corner of the region is separated from the other lowland areas by the rugged Takatimu Range which has extensive scree features not seen elsewhere in the region. To the southeast lies the rolling hill country of the Catlins where a lush and diverse forest can grow right down to the coast. The rest of the southern coast is characterized by dunes with large open bays and estuaries separated by rocky outcrops.

When the glaciers retreated from the uplands and the Te Anau basin after the end of the last Ice Age (10,000 years BP), the lowlands became covered with outwash gravels and mantled with loess but the underlying sedimentary rocks (lignite, limestone, sandstone, and mudstone) are much older and their origin more complex. Greywacke and argillite extends across the north of the region in a broad belt below the schists of Otago but there are also basaltic tuffs, diorite, gabbro, and a range of ultramafic rocks such as serpentine and peridotite (Soons and Selby 1982).

Forests recolonized Southland after the last period of Ice Age glaciation and remained the dominant vegetation cover until about 1,000 years ago (Dawson 1988). Silver beech (Nothofagus menziesii) was present in higher altitudes to the west with red beech (Nothofagus fusca) in the northern mountains. In the lowland areas podocarps and hardwoods were predominant with kahikatea (Dacrycarpus dacrydioides) growing in swampy areas and rimu (Dacrydium cupressinum) on drier sites. Southern rata (Metrosideros umbellata) and kamahi (Weinmannia racemosa) were present in the central hill country and in the Catlins.

Charcoal evidence shows fires began in the region about 2,500 years ago and increased in frequency after the arrival of Maori. These fires led to the loss of large areas of forest and their replacement by tussock grasslands: snow tussocks (primarily Chionochloa spp.) above the treeline and red tussock (Chionochloa rubra) spread over an estimated 45 percent of the region (Department of Conservation 2000). By the time Europeans arrived some forest regeneration had started but most of this land was again cleared for farms and other developments. Livestock had a major impact on the tussock lands and exotic pasture grasses took over areas once dominated by red tussocks. Europeans also drained many of the wetland areas in the lowlands. Some forest remnants have been preserved, mainly in the Livingston, Snowdon, and Eyre Mountains, the Catlins area, the Hokonui Hills, and around Waitutu to the south. However, little lowland swamp survives.

Biodiversity Features

The Catlins Forest Park (420 km²) contains a rich and diverse flora and a wide range of habitats, from the alpine bogs found on the Ajax Plateau to salt marshes and rocky coastal cliffs. In places unbroken sequences of native vegetation run from the coast to the subalpine zone. It is also the only large area of the eastern coast of New Zealand retaining a predominantly natural forest cover (Department of Conservation 1998). Catlins Forest Park contains rimu-dominant podocarp forest, as well as New Zealand’s southernmost stand of silver beech (Nothofagus menziesii). An endemic daisy Celmisia lindsayi, is found on the coastal cliffs. It is home to several endangered birds, most notably the world’s rarest penguin, the vulnerable yellow-eyed penguin (Megadyptes antipodes) (Hilton-Taylor 2000). Mohua or yellowheads (Mohoua ochrocephala VU) have small South Island populations that are generally decreasing, but they have started to recover here following intensive stoat control (Mustela erminea). The Catlins Forest Park coastline is the only place where elephant seals (Mirounga leonina), New Zealand fur seals (Arctocephalus forsteri) and the New Zealand sea lion (Phocarctos hookeri VU) all co-exist (Molloy 1994). New Zealand sea lions have only resumed breeding on the mainland since 1992, and now breed here and along the Otago coastline.

Subalpine and alpine vegetation communities in the Eyre Mountains are in excellent condition and have high levels of endemism and a number of species that are considered priorities for conservation efforts. There are large areas of snow tussock grassland and significant tracts of unmodified indigenous beech forest. The only population of rock wrens (Xenicus gilviventris) known to exist outside the Southern Alps is found here. Endemic alpine species include Carex uncifoli, Hebe biggarii, Celmisia thomsonii, and Aciphylla spedenii. One of the Department of Conservation’s priority species for conservation protection, the South Island tree daisy (Olearia hectori EN), is found in shrub lands outside existing protected areas (Department of Conservation 1998).

Tussock grasslands are important habitat for birds of the open country like Australasian harriers (Circus approximans) and South Island fernbirds (Bowdleria punctata punctata). Tussock dependent reptiles include the green skink (Oligosoma chloronoton), found only in Southland, Otago, and Stewart Island, and the Otago skink (Leiolopisma otagense), which is found only in Otago and Southland. The small remaining areas of coastal tussocks, such as Poa astonii, provide habitat for several species with limited distributions including an endemic chafer beetle, Prodontria praelatella.

The Southland coast and associated wetlands support a wide range of invertebrates and wading birds. Dunes and dune lakes are still found in good condition in Southland. Although they have been extensively modified throughout New Zealand, here they may extend up to 10 km inland. The Waituna Lagoon is notable for its abundant bird life and the extensive marshes along the lagoon. The only mainland populations of one of New Zealand’s rarest plants, Gunnera hamiltonii, are found in stable dune systems on the coast near Invercargill. The other small populations of this ground-hugging herb are found on Rakiura Island (Department of Conservation 1999).

Current Status

Public conservation lands administered by the Department of Conservation include large areas of the forested Takitimu, Snowdon, Eyre, and Blue Mountains, the forests of Western Southland, Rowallan, Longwoods, and Dean, and the Pembroke and Glaisnock Wilderness Areas. Some protected areas were conserved because land development was not economical (Department of Conservation 1998), but other areas were logged prior to their protection.

Lowland shrub communities, coastal dune ecosystems, and tussock grasslands, particularly red tussocks are poorly protected. For example, less than 20 km² of lowland red tussocks are protected. There are a few notable exceptions, such as the Waituna Lagoon, which has been designated a Wetland of International Importance under the UN Ramsar Convention. The area covered by the Ramsar listing will be extended by 200 km² to include the three major estuaries, Toi Toi, Awarua Bay, and the New River. This expansion will include slightly more than 100 km² of the Awarua peat complex and areas of cushion bog which are usually only found in subalpine regions.

Types and Severity of Threats

Justification of Ecoregion Delineation

The Southland Temperate Forests ecoregion largely conforms to Wardle’s (1991) ‘Southland’ Botanical Province. However, the ‘Mavora’ Ecological Region (Department of Conservation 1987) was excluded from the Southland Temperate Forests because the Mavora Ecological Region contains high percentages of grassland vegetation.

References

Dawson, J. 1988. Forest vines to snow tussock: the story of New Zealand’s plants. Victoria University Press. Wellington.

Department of Conservation. 1987. New Zealand topographical map: Ecological regions and districts of New Zealand. Map (1:500,000). Departments of Lands and Survey, Wellington, New Zealand.

Department of Conservation. 1998. Otago Conservation Management Strategy. Otago Conservation Management Planning Series: 7. Otago Conservancy. Dunedin.

Department of Conservation. 1999. The conservation requirements of New Zealand’s nationally threatened vascular plants. Threatened species occasional publication: 13. Biodiversity Recovery Unit. Wellington.

Department of Conservation. 2000. Conservation Management Strategy for Mainland Southland/West Otago 1998 – 2008. Southland Conservancy Conservation Management Planning Series No 9. Invercargill.

Department of Conservation. Retrieved from: http://doc.govt.nz - Te Papa Atawhai.

Hilton-Taylor, C. 2000. The IUCN 2000 Red List of Threatened Species. IUCN, Gland, Switzerland and Cambridge, United Kingdom.

Molloy, L. 1994. Wild New Zealand. New Holland Publishers. London.

Soons, J. and M. Selby, editors. 1982. Landforms of New Zealand. Longman Paul, Auckland.

Wardle, P. 1991. Vegetation of New Zealand. Cambridge University Press, Cambridge, United Kingdom.

For more general information on this ecoregion, go to the WildWorld version of this description.