Bethells Dunes

Size: 90 hectares

Site description

The Bethells Dunes biodiversity focus area includes the sand dunes of spinifex, pīngao grassland or sedgeland (DN2) along the beachfront at Te Henga / Bethells beach. The inland section of this large dune system impounds Lake Wainamu, the largest natural lake in the Waitākere Ranges.

The dunes cover a mix of public and private land on Auckland’s west coast. Bethells Dunes is recognised as a landform of regional significance due to the extensive areas of vegetated and mobile sand dunes, and for the dune-impounded freshwater lakes.

Foredunes and backdunes at Bethells Beach with established vegetation.
The dynamic foredunes at Bethells Beach that become more stable towards the backdunes as scrub and broadleaved coastal species occupy the deeper soil.
Photo credit: Andrew Macdonald, Biospatial Ltd 2018

Dune vegetation

Plant communities on mobile dunes (also known as active dunes) are exposed to constant wind-blown sand and salt spray. The native sand binding species spinifex is common on the Bethells Dunes.

Pīngao, another sand-binding native species, is also found here. It is common along the exposed seaward edge of the dune where the sand is particularly mobile. Pīngao is considered to be at risk of extinction in a national context (At Risk – Declining). Other native plants include tauhinu, shore bindweed and Coprosma crassifolia.

Restoration efforts

Community volunteers have been involved in ongoing restoration efforts with extensive weed control, replanting of native species and animal pest control. The reduction in animal pests has helped tūturiwhatu (New Zealand dotterel) to successfully breed at Bethells Beach.

Related ecosystems

Active coastal sand dunes ecosystem

Spinifex, pīngao grassland or sedgeland ecosystem (DN2)

Dunelands occur where erosion and accretion of sand creates mobile dune systems. Due to the extreme conditions only a few highly specialised, drought tolerant plant species have adapted.

Threat status
Endangered

Regenerating ecosystem

Broadleaved species scrub and forest ecosystem (VS5)

This ecosystem can be found in semi-dry areas on low fertility slopes throughout New Zealand. In Tāmaki Makaurau / Auckland, it is mostly found on south-facing slopes in the south.

Threat status
Least concern