Size: 90 hectares
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.
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.
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.
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.