Abstract: Aprille Gillon.
Wetlands are highly productive ecosystems that support abundant native fauna and flora and provide many essential functions and services, for example, water purification, erosion stabilisation, floodwater storage, groundwater recharge, peat accumulation and biogeochemical cycling.
Despite the vast benefits wetlands provide worldwide loss and degradation still continues, mainly due to agriculture, urban development, population growth and exploitation.
Wetland disturbance can cause altered hydrological regimes, invasive species introduction, soil and water eutrophication, habitat fragmentation and reductions in native fauna and flora leading to an overall reduced functionality.
Ecological restoration is an active practice commonly undertaken in degraded wetlands to re-establish ecosystem functioning, and most commonly includes revegetation, reconstruction of hydrology, weed control, pest management, and native species reintroductions.
Wairio Wetland on the eastern shores of Lake Wairarapa forms a part of Wairarapa-Moana, the largest wetland complex in the lower North Island. Historically Wairio was an abundant kahikatea swamp forest, with a diverse range of waterfowl, waders and freshwater fish. However, the wetland was adversely affected by a draining scheme during the 1960s and 1970s, the construction of Parera Road, and the invasion of willow trees planted for erosion control.
Draining of the wetland, division from nearby lagoons and ponds, nitrogen and phosphorus build-up in waterways and exotic weed invasion all contributed to the poor state of the wetland. In 2005, Ducks Unlimited (DU) in conjunction with the Department of Conservation (DOC) and members of the local community formed the Wairio Wetland
Restoration Committee to manage and restore the wetland to its presettlement state.
Restoration undertaken at the site have included native tree planting, earthworks, weed control, pest management and fencing sections of the site to exclude cattle, have met with mixed success.
This thesis reports on two studies undertaken at Wairio Wetland with aims to inform future restoration efforts.
There had been a proposal to divert nutrient rich water from Matthews lagoon into Wairio Wetland to increase filtration and improve