UC research looking at ways to conserve NZ wetlands

UC research looking at ways to conserve important NZ wetlands

January 16, 2014

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Olivia Burge

A University of Canterbury (UC) postgraduate student is looking at ways to help conserve one of New Zealand’s biggest wetlands.

UC PhD student Olivia Burge is investigating the Awarua-Waituna wetland, in Southland, which was New Zealand’s first and largest internationally-recognised wetland site and at 20,000 ha it is the largest out of 55,000 ha of wetlands recognised nationally. 

New Zealand has an international commitment to protect the existing ecological character of the site. DOC currently manages the wetland through the Arawai Kākāriki programme, which aims to enhance the restoration of three of New Zealand’s foremost wetland sites and apply lessons learnt to other wetlands. The programme provides coordinated investment guided by restoration objectives.

The recent history of Awarua-Waituna wetland includes clearance and drainage for agriculture, lagoon level manipulation and large fires. Current vegetation communities include a mix of wetland species which are stable and not likely to decrease over time; disturbance-induced communities of varying age and biodiversity value which might decrease as the vegetation recovers from disturbance; and some fragments of native forest. 

Species which are rare elsewhere are present at the site, but occur in disturbance-induced wetland communities. Understanding the barriers to natural regeneration will help managers realise potential habitat improvement for a number of threatened species.

``The area of the wetland I am working in is mostly covered in manuka,’’ Burge says.

``It provides important habitat for fern bird and bittern, two threatened species, but we think there is potential for further habitat improvement if forest communities regenerated naturally. It is not clear why the forest is not regenerating. This is the focus of my thesis.

``My results to date suggest that, along with fire prevention, pest control (particularly possums and rats) is a top priority for supporting restoration in the wetland. 

``Possums and rats were not initially thought to be causing problems in the wetland but we have found they are grazing on young forest plants, limiting regeneration. Increasing seed dispersal is another potential management method.

``New Zealand has lost around 90 percent of the estimated pre-human extent of wetlands so there is a huge opportunity for forest regeneration and restoration if we can understand more of the threats and manage them appropriately. 

``Eighty-two percent of pre-human New Zealand was covered in indigenous forest and this figure has dropped to 24 percent, which is a reduction in area of 14,000,000 ha, or 71 percent of the original forest area.’’

Burge’s research, supervised by Professor Dave Kelly, is funded jointly by the Department of Conservation’s Arawai Kākāriki programme and the Miss E L Hellaby Indigenous Grasslands Research Trust.

ENDS

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