Vegetation

Otama estuarine wetland & Otama beach active dunes system.

The Otama estuarine wetland is defined by an assemblage of vegetation adapted to permanently damp or wet conditions. Discreet areas of the wetland can be deliniated by the conditions to which wetland vegetation has adapted such as: permanent dampness, permanent or temporary inundation, and saltwater inundation.

The Otama beach dunes are classified as an “active dune system”, and owe their physical, landscape and ecological characteristics to ongoing or very recent movement by sand. Human modification to the dune system has been very limited, and the dunes act as a barrier to associated saltmarsh. A large proportion of active dunes are bare or semi-vegetated sand, with vegetation dominated by sedges, grasses and shrubs.

It is recognised that native front dune plants play a critical role in the release and subsequent accumulation of sand during and after storms, and provide an important storm buffer for coastal ecosystems.

The restoration area of this project includes two of the most severely damaged ecosystems nationwide, wetlands and dune systems.

Recommended actions

Following a number of key steps outlined in a systematic plan will ensure the revegetation project is successful and sustainable over the long term.

The most commonly undertaken activity in wetland and dune restoration is revegetation, which can be broadly divided into management activities such as: weed control, pest control, encouraging and planting desired species, monitoring and planning;

  • Conduct visual assessment of planting zones as defined in Wetland restoration. A handbook for NZ freshwater systems (Chapter 10, pg. 160).
  • As hydrology plays an important role in defining planting zones, data collected pertaining to hydrology will be useful here.
  • An aerial survey will be useful in mapping broad vegetation types as related to planting zones.
  • Cleary deliniate the wetland restoration area and conduct vegetation survey for the area.
  • Vegetation data should be geolocated in order to allow integration with mapping, and should include significant threatened species and exotic pest plants. Assistance with vegetation survey may be able to be provided by local botanical society.
  • As a baseline use WRC Estuarine Vegetation Survey: Otama Estuary by Meg Graham, 2008.
  • Assistance with vegetation survey has also been provided by 2005 Botanical Society Otama field trip species list (pp10-11).
    Base revegetation plan on defined planting zones as mapped previously.
  • Produce weed management plan including timeline, labour requirements, budget, and control methods.
  • Produce revegetation plan including timeline, labour requirements, budget, and target species.

Vegetation Resources

Restoration of wetland vegetation provides suitable habitat for wetland species and improves biodiversity.

It also increases scenic and functional values of the site. Following a number of key steps outlined in a systematic plan will ensure the revegetation project is successful and sustainable over the long term.

It is recognised that native front dune plants play a critical role in the release and subsequent accumulation of sand during and after storms, and provide an important storm buffer for coastal ecosystems.

A vegetation tool for wetland deliniation in New Zealand by Beverly Clarkson, 2013. Published by Manaaki Whenua Landcare Research.

Wetland types in New Zealand. Peter Johnson and Phillip Gerbeaux, 2004. Published by Department of Conservation and Ministry for the Environment.

A vegetation zonation from saltmarsh to riverbank in New Zealand. Warren King, J. Bastow Wilson, & Martin Sykes, 1990. Published in Journal of Vegetation Science.

Wetlands New Zealand Plant Conservation Network Website. Ropū hononga Koiora ki Aotearoa.

Revegetation Inventory & Monitoring

Standard inventory and monitoring project plan. Published by Department of Conservation. (Document format)

Weeds

Weeds by Kerry Bedmin, 2013. Chapter 9. Wetland Restoration. A handbook for New Zealand freshwater systems, Published by Manaaki Whenua Landcare Research.

Vegetation Reports

Site Assessment Otama Beach Dunes by David Havel, 2017

Very Important! D. Havel describes the dune system in detail, identifies the main invasive species and outlines a weed management approach.

Otama plant species list Auckland Botanical Society filed trip 2005

Note: Otama plants are on the last page of the report.

Estuarine Vegetation Survey Otama Otama Estuary by Meg Graham, 2008