Sand dunes are critically endangered ecosystems, supporting a wide variety of specialist native flora and fauna (Jamieson, 2010). They have declined significantly in the past century, partly due to coastal development and exotic invasions. They are natures’ flood defence system, allowing sand to be dragged out during a storm to create sandbars which reduce the power of the waves hitting the beach. The sand is then gradually returned to the beach and the dunes build up again over time. This process is negatively affected by the use of marram grass (Ammophilia arenaria) to stabilise dunes. This European grass creates a steep dune profile, causing storm waves to gouge out the front of the dune, leaving an almost vertical face which takes a long time to repair itself. In contrast, native grasses such as spinifex (Spinifex sericeus) and pingao (Ficinia spiralis) result in a shallower gradient and allow dunes to rebuild in a shorter space of time.
Wetlands are natures’ filters; sifting harmful substances from the water, as well as protecting against floods and erosion. They provide habitat and food for many species, and recreational areas for activities such as fishing and tramping.
The dominant vegetation on the fore dunes are the native grasses spinifex (Spinifex sericeus), pingao (Ficinia spiralis) and sand tussock (Austrofestuca littoralis). These fore dune plants are well adapted to the dynamic environment, tolerating high temperatures, low moisture conditions, salt spray and burial by sand (Esler, 1970). These species are in good condition on the spit but are threatened by invasive pest plant species and rabbits. The back dune is dominated by pohuehue (Muhlenbeckia complexa) and wiwi (Juncus pallidus).
The areas within our BMP’s are populated by a wide range of species, both native and invasive. One of the main aims of our work is to provide a safe, natural environment in which native species can flourish, and to minimise the impact of pest animals through eradication programmes.
The native flora of Maketu provides high-value breeding habitat for native birds, specifically the Northern New Zealand dotterel (Charidrius obscurus), variable oystercatcher (Haemantopus unicolor), red-billed gull (Larus scopulinus) and white-fronted tern (Sterna striata). Breeding success of birds such as the New Zealand dotterel has improved recently, which, combined with the presence of the rare Black-billed gulls nesting on the spit, is a sign that pest control by MOWS volunteers is having a positive effect.
A wide variety of native and migrant birds also use the spit and associated mudflats for feeding and roosting, especially during the winter, including: bar-tailed godwits (Limosa lapponica), royal spoonbills (Platalea regia), wrybill (Anarhynchus frontalis) and the extremely rare and threatened fairy tern (Sterna nereis).
Shore skinks (Oligosoma smithii) occur all along the spit, and MOWS conduct regular surveys to estimate the population size and distribution. Animals are collected in pitfall traps and details such as location, length, weight and condition are taken as part of an ongoing project. All animals are released immediately after measurements are taken.
The dune systems have a high incidence of native invertebrates. Well over 150 species have been recorded, including five new or un-described species, notably a new spider and a new beetle. MOWS conduct surveys on a regular basis, using pitfall traps to collect specimens.
New Zealand is home to a wealth of marine life, and a wide variety of species are found in the waters around Maketu. There is a large population of New Zealand Fur Seals (Kekeño) as well as sharks, dolphins, whales, stingrays and jellyfish. Unfortunately, marine mammals are sometimes found stranded on the local beaches. If you find one, either alive or dead, please call DOC on 0800 362 468 or Project Jonah on 0800 494 253.
References: Esler, A. E. (1970). Manawatu sand dune vegetation. Proceedings of the New Zealand Ecological Society, 17: 41-46.
BirdLife International (2012). Charadrius obscurus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. . Downloaded on 03 August 2012.
Jamieson, S. L. (2010). Sand dune restoration in New Zealand: Methods, Motives, and Monitoring. Unpublished MSc Thesis. Victoria Universityof Wellington, Wellington, New Zealand. 158p.