MU-E & MU-G1 – Mid Takaka Valley

Project De-Vine Environmental Trust (PDVET) has made significant progress with controlling Banana Passion Vine and Old Man’s Beard in the Golden Bay area. Stages 1 to 6, now referred to as Management Units MU-D1 to MU-D6, addressed the worst areas of vine infestation from Rameka Creek to Pohara and on to Wainui. The largest two were Pohara (MU-D3) and the lower Takaka Valley (MU-D6) involving over 180 and 430 properties respectively. This next project area, incorporating MU-E and MU-G1, is to conduct a large number of assessments of the pest vines and other invasive plants on farms and other properties throughout the middle Takaka valley in Golden Bay, adjoining Kahurangi National Parks areas and not far from Abel Tasman National Park in Golden Bay (see #1 Map of Management Units of Golden Bay November 2019). The aim is to stop the spread of pest plants across this project area. A combination of the Lotteries board grant and secured funding shall allow the Trust to provide effective weed pest control work for 3 years.

MU-E & MU-G1 focus on the following:

Properties throughout the middle Takaka valley in Golden Bay, adjoining Kahurangi National Parks areas and not far from Abel Tasman National Park in Golden Bay. Some of these properties contribute to creating a “halo effect”, or weed free zone, that we wish to establish around KNP. This project aligns well with the aims of the Cobb Mitigation Fund, relating to mitigation of the effects of the Cobb Dam on the Takaka valley. The Tasman Environmental Trust administers the Cobb Mitigation Fund. They have committed to contributing toward the assessments ($7k) and providing $20k per year for three years (part contribution) toward the costs of weed control work. These grants provide a sizeable part of secured funding for this application.

Over the past three months, 170 property assessments have been completed with 101 found to be clear of high priority (very invasive) pest plants.

This assessed area represents over 99% of the project area (excluding those suburban sections with less that 1200m2). The remaining smaller properties, >1200m2, are being assisted with free gel and advice if the properties are found to have pest plants present. These assessments provide a best estimate of control work required on each property. The assessments aid planning for control work on the key pest plants: Old man’s beard, Banana passion vine and four other key targeted plants (Climbing asparagus, Woolly nightshade, Purple pampas grass and Yellow or Italian jasmine) see the main question #2 in the Lotteries application “What community need do you propose to meet?” For more details about each plant.

Once the property assessments are completed, the Trust will undertake the following: (see #2 MU-E + G1 Summary of Property Details + Control Hours 20200304 the property details have been deleted, for privacy reasons, but can be supplied if requested)

Provide property owners, once the funding decision is made, with a summary of their property’s density and distribution of the six key pest plants and some less common control plants in the Regional Pest Management Plan (RPMP) like Taiwanese Cherry, with one known site in this area.

• Up to 30 property owners will be offered control work to a maximum of 40 hours per property for the first year to ensure that outlying small infestations are well controlled, and the large ones reduced in size over the three-year project period.
• This pattern will continue for the second and third years, with a reduction of hours offered to allow visits to other properties, to ensure that the properties are revisited and “zero density” of the targeted mature pest plants is achieved for as many properties as possible.
• Those properties that wish to contribute $ towards further work by the Trust will have the opportunity to do so.
• Priority control will be given to some plants like Woolly nightshade and Old man’s beard, as well as well the single properties with small sites of Taiwanese Cherry, Kiwifruit vines and Yew which will require relatively low hours to fully control each year. These are a big threat to the many QEII covenants in this area, where birds roost at night and wind, can carry the seeds.
• Where possible the outer edges, low density, of spread of Yellow / Italian jasmine will be controlled along the southern end of the project area on the properties nearest to the Kahurangi National Park boundary.

Property owners with small property sizes and low levels of weed infestation, who have received three years of control work, will be expected to continue with control work until seed sources are exhausted in the soil. This is contained within the agreement that landowners sign before Project De-Vine Environmental Trust commences work. (See Sample of our agreement: #3 Subsidised pest vine control work in MU-E & G1 agreement Blank 20191011.)

This project addresses the issue of attrition. That is, follows up on annual weed control work over the past three years. PDVET has found that even after three years of control work on properties with large numbers of vines and other key invasive plants / trees, there remains a seedbank that requires two to three year cyclical control to maintain re-infestation at a level that prevents vines and other key invasive plants / trees from reaching maturity, flowering and producing copious amounts of seeds. Many properties have steep slopes with rocky bluffs and deep gullies. Just to carry out an assessment takes a significant amount of time, energy, and expertise. This project area is critical for the Trust to prevent this damaging regenerating cycle from reseeding into the areas we have controlled already lower down the valley. Therefore, curbing the spread of weed vines and other key invasive plants / trees across the bigger project area.

By carrying out extensive pest plant control work, landowners carrying out riparian plantings with native trees will benefit from improved growth and fewer losses. This has been a problem in other parts of New Zealand, with pest vines especially smothering newly planted areas. Weed control provides both conservation and financial benefits to property owners.

PDVET’s pest plant control work along and near to the boundaries of ATNP and KNP will help protect the Parks for generations to come and continue to support the on-going work within these parks by Project Janszoon and the Department of Conservation.