Marlborough's Ecology
The Marlborough environment is almost two distinct areas in relation to ecology and biodiversity. The Wairau River is the approximate divider between the drier, less forested south Marlborough area (about 700 000 ha) and the wetter more forested north Marlborough and Sounds area (about 250 000 ha). Together, these areas form a distinctive part of New Zealand's natural environment. The diversity of the region in terms of climate, geology, topography, and its central location within the country, mean that a large variety of plants and animals occur here, a number at their southern or northern limits of distribution. Click below for the map.
Map Showing the two Distinct Areas of Marlborough (538 Kb)
Marlborough, particularly its lowland environments, and the dry eastern areas, has been quite highly modified by human activity over the past 700 years. Early Maori fires cleared dryland forest vegetation in eastern areas and later further clearance of land and drainage of wetland areas occurred to obtain land suitable for farming. Many bird species once common to most of New Zealand are now extinct in Marlborough (moa species, kiwi and kakapo). Other bird species like tui, bellbird and kereru are not found in large parts of the region due to limited suitable habitat. Many introduced pest species of both plant and animal do well in Marlborough, particularly pigs and goats.
Marlborough has been identified as one of five centres of biodiversity in New Zealand, due to the concentration of endemic species which have evolved in the dry rocky conditions in the southern part of the region.
South Marlborough
In South Marlborough the dry climate and greywacke and other largely sedimentary rock types have created a wide diversity of habitats, reflected in the character of the native vegetation.
The region includes many of the species that make up the mixed forests (beech, podocarps and broad-leaved trees), shrublands (including "grey scrub") and grasslands (silver tussock and snow tussock) which are widespread throughout New Zealand.
By virtue of its central location in terms of latitude, the area has species near the southern limits of their range (particularly lowland forest species like rangiora) and some northern limits.
The extreme dryness means that plants adapted to those conditions are prevalent. Interwoven into all this is the unique endemic element, including species that have evolved in the special conditions, such as the pink brooms, New Zealand lilac and Marlborough rock daisy. The widespread occurrence of dry rocky lowland habitats seems to be the key factor for most of the distinctive local species.
The native fauna (mainly insects and reptiles), follows this pattern too, and the combination makes South Marlborough one of the genetic diversity centres of New Zealand.
In the lowland parts of south Marlborough, widespread historical land clearance and minimal public conservation land means that private land owners have an important role in managing remaining areas with ecological and biodiversity values.
A report providing a summary of the results of the ecology and biodiversity of South Marlborough resulting from a combination of Council's Significant Natural Areas survey and the Department of Conservation's Protected Natural Areas survey of private land is available from Council.
North Marlborough
In North Marlborough a moister climate and metamorphosed schist geology combine with steep topography and complex coastline to create a further variety of habitats and ecological communities.
This includes broad-leaved forest in gullies, black beech forest on headlands and lowland spurs, hard, red and silver beech occurring on lower to higher slopes respectively, and podocarp species like totara, rimu, matai and kahikatea in the heads of bays and on the lower slopes, although many of these were logged for timber.
A significant amount of original forest cover remains, and about half of the land area north of the Wairau River is in conservation estate under the management of the Department of Conservation. Regeneration of land once cleared for pastoral farming is common over large areas, with vigorous native shrublands including manuka, kanuka, tauhinu and broadleaf species establishing.
The ultramafic mineral belt which runs through parts of the Sounds supports some distinctive vegetation and a number of rare or unusual plants are found in those areas.
The area also has important habitat for both freshwater and coastal fish and other species.
The Department of Conservation has a strong presence in the Sounds and a number of the islands like Maud and the Chetwodes, are used for conservation projects to protect endangered bird and animal species.
Iwi groups are also involved in conservation work. A number of private landowners are carrying out significant conservation projects as well, often linking the potential for eco-tourism and conservation.
A report providing a summary of the results of the ecology and biodiversity of North Marlborough resulting from a combination of Council's Significant Natural Areas survey and the Department of Conservation's Protected Natural Areas survey of private land is available from Council or can be viewed online.