02 February 2018

Manawatu Estuary spartina control yielding results

Department of Conservation (DOC) rangers have been putting in the hard yards to free the Manawatū Estuary from the clutches of spartina, a nasty weed which takes over mudflats.

Today is World Wetlands Day, and Department of Conservation senior ranger Sue Moore wants to draw attention to the successful spartina control in the Manawatū Estuary.

“In the late 1980s spartina covered around 90ha of the Manawatu Estuary’s mudflats. The shorebirds couldn’t feed where the spartina was growing and it just kept spreading.

“Now, after 20 years of ground control work, only a few pockets of spartina remain. Eradication is tantalisingly close.”

Sue says it’s critical that spartina control and surveying continues until it’s all gone.

“We are still carrying out both ground-based and aerial surveying for spartina in the estuary and ground-based spraying annually.”

The estuary, just south of Foxton, is one of the largest in the Lower North Island. It’s been classed as a Wetland of International Importance under the Ramsar Convention since 2005, meaning the ecological importance of its vegetation and landforms is internationally recognised, as is its value as a feeding and roosting site for wading birds.

Sue says, “spartina has an interesting history at Manawatu Estuary. This is where it was first introduced to the country back in 1913 to reclaim land for grazing.”

“Over time concerns around long-term impact grew. The problem is, it grows fast and forms dense, knee-high mats that reduce water flow and increase flooding.

“Fast-forward to the 1990s and spartina was recognised as a noxious weed. Legislation is now in place to prevent it from being planted.”

The Manawatū region was once filled with a variety of wetland ecosystems. Sadly, less than 4% of those wetlands remain today.

World Wetlands Day celebrates the establishment of the Ramsar Convention on wetlands in 1971. This is a global environmental agreement for wetlands.

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