Topic: Te Arai Dunes
Topic type:
Te Arai's dunes are made up of layers of sand that date back 120,000 years to the Pleistocene epoch. Its upper Holocene sand layers, circa 12, 000 years ago, come originally from the ancestral Waikato River. Te Arai dunes are in an active state of equilibrium, though were transgressive before pines were planted. They are host to a number of threatened species at Te Arai, including pingao, sand coprosma, sand tussock, shore skink and katipo.
Dunes
After fire led to the de-forestation of Te Arai around 800 years ago, a vast area of moving sand dunes was created from the Mangawhai sandspit right along to the Pakiri stream. View an aerial photo of the dunes circa 1940.
Enright and Anderson's study on the formation of the dunes uncovered large scale erosion from the deforestation. The shifting sands in addition buried the soil layer inhibiting regeneration. Click here for the full report. The area was subsequently re-planted in pine forest, beginning in the 1930s with the majority planted out after 1963 (McKelvey, 1999), to protect adjacent farmland. Even with this intervention, the dunes remain relatively intact compared to many in the Auckland region. Transects of the dunes show the current Holocene layer of sand, is thinly spread on top of Pleistocene dunes around 120, 000 years old. Click here for J. Dahm's report. So although the dunes are now planted pine forest, the ancient topography of the dunes beneath them remains, at least in the southern section of the forest. To the north, the ancient dunes were modified significantly as a result of the golf course creation in 2013.
In 2010 Rebecca Stanley also wrote of the importance of Te Arai's dune systems" The Auckland region has 15% of its dunes remaining. Over 2/3rds (68.39%) of Auckland’s active dunelands have been lost since records were collected in 1950, which is a notably high rate compared with many other regions (Hilton 2000). Much of what does remain is degraded or under threat from proposed and existing development (Williams et al. 2007), crushing by people and vehicles, and competition with weeds. Only a few of Auckland’s more remote beaches, such as Te Arai, retain components of original dune vegetation, and their long term persistence is heavily dependent on their continued remoteness" Click here to read the full document.
References:
Sand Forests : a historical perspective of the stabilisation and afforestation of coastal sands in New Zealand / Peter McKelvey
McKelvey, P. J. (Peter John), 1926- Christchurch, N. Z. : Canterbury University Press, 1999. Printed Text.
