Kaukapakapa Estuary Scientific Reserve

Size: 395 hectares

Area description

Kaukapakapa Estuary Scientific Reserve is approximately four kilometres north of Helensville. It lies on the northern side of Kaukapakapa River. Purchased by the Crown in 1968, it is now administered by the Department of Conservation. This biodiversity focus area encompasses the entire reserve and includes a variety of ecosystems.

Kaukapakapa Estuary Scientific Reserve with river and forest.
Kaukapakapa Estuary Scientific Reserve showcasing the large kauri, podocarp, broadleaved forest (WF11) and large pockets of kahikatea-dominated forest (MF4). Significant saltmarsh and mangroves can be found adjacent to the meandering Kaukapakapa river.
Photo credit: Andrew Macdonald, Biospatial Ltd 2018

Ecosystems

A large area of kauri, podocarp, broadleaved forest (WF11) covers the steep, south-facing slopes from a high ridgeline to kahikatea-dominated forest (MF4), freshwater wetland (WL10) and saltmarsh and mangroves (SA1) at the base. Tidal reaches of the Kaukapakapa River extend along the southern boundary of the biodiversity focus area. There are very few remaining examples of intact native vegetation sequences from ridgeline to river on this scale in Tāmaki Makaurau / Auckland, consequently this is part of the reason why it is of very high biodiversity value.

Kaukapakapa Estuary Scientific Reserve with river and forest.
Kaukapakapa Estuary Scientific Reserve, north of Helensville, showing the extensive area of forest that extends north of the Kaukapakapa river.
Photo credit: Andrew Macdonald, Biospatial Ltd 2018

Vegetation

The forest contains a diverse range of native plant species, documented by members of the Auckland Botanical Society on several excursions. Kauri was milled from the reserve by early owners. It is now regenerating in dense young stands (rickers), particularly on ridges and spurs. Other species in the canopy include:

  • tānekaha
  • rimu
  • rewarewa
  • taraire
  • tōtara
  • kānuka.

With pūriri and kōwhai along the lower margins of the forest.

The kahikatea forest at the base of the hillslope is an example of an ecosystem much reduced from its original extent. It was heavily milled for timber and the low-lying land it occupies was extensively cleared for the development of farms and urban areas. Consequently, this ecosystem type has a regional threat ranking of Critically Endangered.

Kauri forest and other emerging trees of Kaukapakapa Estuary Scientific Reserve.
Looking south, the matrix of kauri and other emerging tree species that occupy the steep slopes of Kaukapakapa Estuary Scientific Reserve.
Photo credit: Andrew Macdonald, Biospatial Ltd 2018

Native fauna

Mātātā (fernbird) have been recorded in the wetlands close to the river. There is also a colony of shags roosting in kauri and tōtara trees. A diverse range of other native birds have also been recorded within the reserve during various surveys.

Threats

Kauri dieback, a soil-borne pathogen capable of killing kauri trees of all ages, is present within the forest.

Related ecosystems

Mild forest ecosystem

Kahikatea forest ecosystem (MF4)

This mild forest ecosystem occurs along streams, rivers and in flood plains where soils remain water-logged for long periods during the year.

Threat status
Critically endangered

Coastal saline ecosystem

Mangrove forest and scrub ecosystem (SA1)

Mangrove forest and scrub is found in tidal estuaries, inlets and where salt water meets fresh at the mouths of rivers and streams. This ecosystem has a range of distinct plant communities that provide habitat for birds and fish.

Threat status
Least concern

Warm forest ecosystem

Kauri, podocarp, broadleaved forest ecosystem (WF11)

Once widespread across the Auckland region, this warm forest ecosystem contains a range of podocarp and broadleaf trees on different landforms. It is an ideal habitat for birds, bats and lizards thanks to an abundance of fruit and nectar.

Threat status
Endangered

Wetland ecosystem

Oioi, restiad rushland and reedland ecosystem (WL10)

Typically found on coastal stream margins where freshwater meets saline, this ecosystem is characterised by abundant oioi. Mātātā (fernbird), matuku (Australasian bittern), banded rail (mioweka) may be present in some areas.

Threat status
Endangered