Researchers have identified hotspots for the conservation of maire tawake or swamp maire in the Wellington region, hoping to save this threatened native tree from the deadly myrtle rust disease.
Swamp maire is thought to have been common in the wetlands that once covered the Wellington region. However, farming and urban development have significantly reduced its numbers. The arrival of myrtle rust in 2017 added a new threat and the tree has a conservation status of “nationally vulnerable”.
Priority areas for its conservation have now been mapped in the western suburbs of Lower and Upper Hutt and in the towns of Paraparaumu, Waikanae, Ōtaki, Masterton, Carterton, and Featherston. These priority areas comprise up to 52 km2.
“We’ve identified sites that are likely to have the highest abundance of swamp maire and the lowest risk of myrtle rust. They’re also easy to access, so we think focusing on these sites offers the most cost-effective conservation strategy,” says Dr Sarah Herbert, a researcher in biological sciences at Te Herenga Waka—Victoria University of Wellington.
Dr Herbert says the sites could act as refuges for swamp maire, with additional planting undertaken to help maintain the tree’s population as myrtle rust spreads.
“Myrtle rust is a fungal plant pathogen that is primarily spread by the wind. It has a devastating effect on swamp maire, causing an almost complete loss of flowers, fruits and new leaves. There’s an urgent need to identify sites where conservation and wetland restoration can take place to help ensure this treasured tree’s survival,” she says.
In addition to the priority sites for conservation, the researchers identified other areas that could act as refuges for the tree but these areas would require more intensive management.
Pockets of less accessible land in the wider Wellington region could also be considered as refuges for the tree’s conservation, she says.
The researchers were able to identify areas for swamp maire conversation by using models of the Wellington region’s soil moisture and plant distribution to pinpoint sites where swamp maire was likely to be growing. They then mapped the risk of myrtle rust infection in these areas and graded sites by how easy they were to access.
