It may be known as New Zealand's iconic native Christmas tree, but to Marlborough, the pohutukawa is little more than a potentially invasive weed.

Wild pohutukawa have established themselves in the Marlborough Sounds, but according to the North Marlborough Significant Natural Areas Project report, the tree is not welcome.

Pohutukawa, along with puriri, karo and even kauri, don't occur naturally in the area and are considered a threat to the area's natural integrity.

The report urges people to plant local equivalents such as southern rata, totara, kohekohe and kohuhu, preferably plants raised locally.

The report, launched last week, is the culmination of nine years of surveying ecological communities and species on private land in Marlborough north of the Wairau River.

It has identified 630 environmentally important sites warranting protection over 43,000 hectares.

The launch of the report marked the official end of field survey work.

The report said an "impressive" range of native ecosystems remained on private land throughout the area, and there were still opportunities to protect, restore and enhance what was left.

Severely depleted ecosystems were mostly the forests on valley floors and coastal flats and wetlands, while kanuka forests, tree ferns and shrublands had "greatly" increased because primeval forest cover had been cleared.

Further pressure would be put on the natural environment by changes in land use and land subdivision in coming years, it said.

Exotic plants in gardens in the Marlborough Sounds could create weed problems, while domestic pets threatened native species such as penguins, weka, seabirds and lizards.

People could live in harmony with the natural world as long as they were aware and sensitive to the environment, the report said.

Numbers of feral pigs, deer, goats, possums and hares had increased in recent years, the report said, and this had a serious impact on native flora and fauna.

Wilding conifers were the greatest weed threat in north Marlborough, particularly since pastoral farming had wound down in the area and commercial exotic forestry arrived in the mid-1970s.

Old man's beard was also a growing problem, the report said, and was too large-scale for individual landowners to control in several areas in Marlborough.

Marlborough District Council environmental scientist Nicky Eade, who co-wrote and compiled the report with ecologist Geoff Walls, said work with landowners to protect certain areas of the region and monitoring of sites would continue.

ECOLOGICAL DISTRICT SURVEY

A snapshot of some results of ecological district survey work:

D'Urville: Shore milkweed, a shore plant that is nationally endangered, is found on a few sites on western d'Urville Island.
South Island kohekohe forests are found only in northern Marlborough and at the base of Farewell Spit. In the Marlborough Sounds, kohekohe flowers are present only on pest-free islands, and possums damage the kohekohe canopies in other places.

Cook Strait: This area is the stronghold for both of New Zealand's tuatara species, the Cook Strait tuatara and the Brothers Island tuatara. It also has one of Marlborough's few dune systems. But red-billed gull numbers are dwindling.

Sounds: The Sounds is home to many tui, kereru, bellbird, tomtit, brown creeper, silvereye, fantail, weka and grey warbler. At least 14 species of native freshwater fish were recorded in the Sounds' rivers and streams. Of note were the longfin eel, lamprey, giant kokopu and shortjaw kokopu.

Pelorus: Weka are extinct in other areas of New Zealand but are still relatively common in north Marlborough. This threatened species is vulnerable to attacks from pigs, dogs and cats and smaller predators.
Kereru are common in north Marlborough.
The Pelorus district has the highest rainfall in Marlborough (up to 2600mm) providing a perfect habitat for mosses and ferns.

Para: Many bird species live here, including wetland species, and 14 species of freshwater fish. There are two areas of trees on private land in Kaituna and one on public land at Koromiko that the Marlborough District Council is helping the local community to restore to forest using plants raised from local sources.

Fishtail: There is a half-hectare wetland of harakeke (lowland flax) and sedges in a valley surrounded by commercial forestry that will remain if the area is carefull

- The Marlborough Express