Date:  18 December 2018 Source:  Office of the Minister of Conservation

Published online in the New Zealand Journal of Ecology, the scientific report details wetland loss in Southland by analysing and comparing satellite images of wetlands taken in 1990 and 2012. This covers a longer timeframe than any other Southland wetland loss study.

“The study’s timeframe is significant. After 1990, legislative tools were put in place to help protect the natural environment such as the Resource Management Act 1991, and agencies such as DOC and regional councils were formed,” Eugenie Sage said.

“Ideally, the rate of wetland loss would decrease with legislative protection, but in fact the report says the rate of wetland loss in Southland has been 0.5 per cent per year since 1990 – that’s a rate of 157 ha lost per year. And if we add areas that have been partially drained, the rate goes up to a 1 percent decline per year.”

The report shows that of the 32,814 ha of wetland in the study area, 3,452 ha have been completely lost and a further 3,493 ha are at risk due to the presence of drainage and declines in vegetation. This represents a 23 percent decline since 1990.

Mapping indicates that conversion from wetland to agricultural and horticultural land uses accounts for 60 percent of the wetland loss. 97 percent of the wetland loss or degradation has occurred outside conservation reserves and is predominantly on private land.

Eugenie Sage said the report adds weight to evidence that more must be done to protect wetlands

“Wetlands are an integral part of a healthy landscapes and ecosystems, functioning as nature’s ‘kidneys’ to filter and protect water quality.  Wetlands function as nature’s sponges. They capture sediment and nutrients, slowly filtering water to drought-prone areas. They provide home for rare and threatened wildlife and plants.

“Great restoration work is being carried out by DOC, councils, community organisations and some private landowners, but we’re still seeing substantial and ongoing loss of wetlands. The trend must be reversed so we don’t lose wetlands altogether.”

Eugenie Sage says work has already kicked off over the past 12 months to provide wetlands with more protection.

“DOC is investigating options for wetland sites to be protected under the Ramsar Convention on Wetlands. DOC is also working with the Ministry for the Environment to develop policy to improve wetlands protection.”

The report is available on the New Zealand Journal of Ecology website.

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