Mission Impossible! made possible by the UCBP weed eradication team.

Transcription

1 Mission Impossible! made possible by the UCBP weed eradication team. December 2015 A flora and weed survey was undertaken exactly one year ago on a property in one of the more remote and inaccessible areas of Pillar Valley, located in at the base of the Coast Range, east of the historic city of Grafton in north-eastern NSW. That survey work was undertaken by volunteers from the Clarence Environment Centre, as its in-kind contribution to the federally funded Upper Coldstream Biodiversity Project, a four year weed and feral animal control program aimed at enhancing biodiversity values across the region. However, as well as identifying high levels of flora diversity, the survey also reported serious infestations of the invasive weed Lantana camara. A dense thicket of invasive Lantana in an area heavily impacted by logging The 'sea' of Lantana, resulting from the extreme disturbance inflicted by excessively heavy logging, presented a daunting challenge. That disturbance occurred some 30 years earlier, in forest that today would have been identified as an endangered floodplain ecological community, and would not be allowed under current law. However, somewhere in the middle of the above image, is a creek line, completely over-topped by weed, suggesting that the logging, which removed large trees from the creek bank, was very likely illegal at that time. The current owners are determined to rehabilitate the site and return it to its former state, which was largely tall wet sclerophyll and palm forest. It was clear from that early survey that access was going to be the biggest problem. Obviously there had been logging tracks, but those had long since become overgrown in most places, and gully crossings were washed out, so a plan of action was hatched.

2 Volunteers working to reopen old logging trails, encountered washed-out gullies such as this that needed filling to allow access by a 4 wheel drive vehicle. In this case some 2km of track had to be 'patched-up' and a further kilometre completely repaired and reopened, and much of that work was undertaken by landowners and Environment Centre volunteers. The reopening of old logging tracks to allow access by the weed eradication team using a 4 wheel drive vehicle could have been easily achieved with a bulldozer. However the whole focus of the project is to undertake the work with as little impact on the natural environment as possible by minimising any disturbance, while at the same time minimising costs, to allow the funding to stretch as far as possible. Of course not all the route was overgrown by dense regrowth, other sections were easily opened up by a volunteer using a chain saw, the whole process resulting in a low level of disturbance which would Some sections were easier than others, requiring only a few minutes work by a volunteer with a chain saw prevent erosion or other environmental damage that would have resulted through the use of heavy machinery. As it was, it only took a few days work, and some sweat, to accomplish what had appeared to be mission impossible, so the rest was then up to the professional weed team. The professional weed team preparing to work Again the focus is on minimising impact on the natural environment through the choice of control methods.

3 Dense Lantana such as this smothers all native herbs and shrubs, and can be easily treated by chemical spraying without damage to native species. Hand work, as opposed to using machinery, is clearly the best way to achieve minimal impact, and where there are heavy infestations, such as those above and left, where most native herbs and shrubs have been smothered, chemical spraying can be used without fear of damage to native vegetation. To minimise impacts even further, the weed team uses 'splatter gun' technology which delivers concentrated droplets of herbicide in a targeted manner thus avoiding collateral damage. Dense Lantana amongst emergent native trees is best dealt with using the splatter gun technique to avoid collateral damage And this, pictured right, is the required result; dead Lantana with minimal collateral damage to native species. However, it is important that these expanses of dead Lantana, which will take possibly years to fully break down, experiences regrowth of native species, and this may need manual planting or seeding with pioneer species if natural regeneration doesn't occur. The project team has been mentoring landowners, impressing on them the need for regular follow-up weed control until a forest canopy is re-established, a process that could take upwards of ten years.

4 Where Lantana is relatively sparse, cut and paint is the treatment method of choice, which is best undertaken by a team of two, one cutting stems close to the ground with loppers, while the other immediately applies poison to the cut stump. Hand pulling is also an effective control measure, especially where soils are loose enough, and when working in areas containing high conservation value vegetation, such as rainforest. One year on from the original assessment, the results are dramatic. Dead Lantana as a result of splatter gun spraying, with minimal collateral damage. It could take well over a year for the dead Lantana to break down, but native plants can now grow up through the dead stems

5 The Upper Coldstream Project area is situated at the heart of a region sometimes referred to as the MacPherson - Macleay Overlap, an internationally recognised biodiversity hotspot, and with 44 threatened species identified in the project area to date, the Pillar Valley corridor is now being recognised for its high levels of biodiversity. Much of the project area lies between Pillar Ridge and the Coast Range, which supports contiguous forested areas, providing a crucial wildlife movement corridor from Glenugie State Forest to the south to Pine Brush State Forest to the north. To date, priority areas containing high conservation value vegetation have been treated for weeds on more than 40 properties in the Project area, and with more than 18 months of the 4 year project remaining, we are confident of making a real difference to this important north - south wildlife movement corridor. Compiled by John Edwards Honorary Secretary Clarence Environment Centre * * *