The hunt is on for the invasive weed stevia in the Ravenshoe and Herberton region.

Stevia ovata, or candyleaf, is in flowering season so now (June) is the best time to identify it.

Terrain NRM is working with Tablelands Regional Council on a project to control this weed and to keep it from spreading any further in Australia than the Atherton Tablelands, the only place it has been found.

Flowering season – May-June – easiest time to identify stevia

Terrain’s Evizel Seymour said stevia, which has the potential to compromise grazing land and natural vegetation, is controllable if everyone works together.

“Research has shown the seed only lives for 18 months and is not as mobile as something like Siam weed,’’ she said. “It was first found in this region in 2007. The growing season is February to May with a flowering season from the end of May through June.

A controllable weed if everyone works together

“We know this is one of the weeds we can get on top of. The best time to control stevia is before it flowers but identifying it is the first step to controlling it.”

Terrain NRM secured funding through the Queensland Government’s Queensland Feral Pest Initiative to follow on from earlier stevia control work by partnering with Tablelands Regional Council to work with landholders and others including Ergon Energy, Powerlink, Clean Co and the Queensland Parks and Wildlife Service.

Control work, with herbicides, is reducing the size of outbreaks on private and public land.

“Getting to stevia before it flowers and sets seeds means there is no seed bank for the future,’’ Evizel said. “By July to August the top of the plant dies off naturally but the bottom can re-shoot with moisture and the problem continues unless it is being controlled.”

More than 22,000 pond apple trees have been hand treated along creeks in the Upper Murray region this year in an effort to blitz the invasive species that is being spread by flood. Following the treatment of 115 hectares last year, ground teams have expanded their search to take in Corduroy and Boar Creeks in the Murray catchment.

A weed of national significance, pond apple was introduced to Australia in 1912 as grafting stock for commercial custard apple crops and is now a major environmental weed in the Wet Tropics. Removal work is part of Terrain NRM’s “Fish Homes and Highways” project and is funded by the Australian Government’s Reef Trust.

Terrain’s Deb Bass says the spread of pond apple is especially worrying for its potential to impact mangroves.

“Pond apple forms dense stands in swampy areas and is capable of replacing mangrove or freshwater wetland ecosystems if left unchecked. We’ve treated approximately 150 hectares this year.”

Seeds are usually spread in big quantities in flood waters so the ground team is working from the upstream reaches out toward the coast. Feral pigs are also proving to be prolific seed spreaders.

“Whilst pond apple is not considered good to eat by humans, feral pigs think the fruit is pretty tasty.  The weed team are guaranteed to find big clumps of pond apple when they follow the pig tracks into the forests,” said Ms Bass.

The silver lining is that the seed bank is only viable for two years. Some weeds have seeds that will germinate many years later, but pond apple can be effectively controlled by treating the same area two years in a row.

Ms Bass said it is critical that weed management programs are properly funded and managed.

The ongoing battle with weeds in the Wet Tropics region has led to a three-year project across 40 hectares of land that has trialled different methods on the edges of world heritage rainforest.

Terrain NRM has worked with the Cassowary Coast, Douglas and Tablelands regional councils on projects that are buffering world heritage forest from fire and weeds, and restoring woodland habitat. They have also involved revegetation work.

Project coordinator Chelsy Maloney said the goal was to improve the resilience of big patches of native vegetation by managing emerging threats in smaller patches of neighbouring vegetation.

Restoring fire-damaged rainforest near Silkwood

In the Cassowary Coast region, the focus was a fire-damaged section of rainforest on a council reserve along the edges of world heritage rainforest.

“With the likelihood of more rainforest fires given our changing climate, it’s important to learn how to best restore these areas,’’ Terrain project coordinator Chelsy Maloney said.

“Cassowary Coast Regional Council worked with us on a weed management and revegetation project where we trialled low-cost assisted regeneration to support rainforest restoration. We found that by managing the high threat weeds, more space and less competition was created for natural recruitment and pioneer species. In the short term, the forest condition showed a definite improvement.”

Weeds were managed on 3.5 hectares of world heritage rainforest and a strip of revegetated land along the roadside.

Revegetating woodland understorey near Ravenshoe

In the Tablelands region, an infestation of guinea grass and lantana in council reserve land beside South Cedar Creek at Ravenshoe was the focus.

“In woodlands the canopy can often be intact while the understorey is overtaken by weeds. By managing lantana and guinea grass, we’ve started to see lots of different understory species recruiting across 10 hectares, and an increase in native species overall.

“We also trialled high-density understorey revegetation work on 1.5 hectares in an attempt to out-compete exotic pasture grasses such as guinea grass, and there have so far been really good results.”

18 October 2021

A new $250,000 grants round is opening for threatened species recovery team members and landholders with priority areas of rainforest in the Wet Tropics region.

Terrain NRM is contacting landholders who have properties with large areas of cassowary habitat or coastal rainforest, or even small patches of critically-endangered Mabi forest.

Grants for tree-planting, weed removal, nature refuges

The grants are for tree-planting, weed removal and nature refuge projects. They are part of Terrain NRM’s Building Rainforest Resilience Project.

Project coordinator Tony O’Malley said landholders and recovery group members had achieved strong results in the first two rounds of grants – with buffer zones and corridors planted for world-heritage rainforest, weeds removed ranging from guinea grass to raspberry, and the creation of nature refuges in Kuranda and Mission Beach.

“Last year, the landholders and recovery groups involved in this grants program achieved weed management work on more than 50 hectares of priority habitat, revegetation projects on over 17 hectares and 150 hectares of voluntary habitat protection agreements,’’ Mr O’Malley said.

Landholders enthusiastic about improving habitat

“The enthusiasm of the people we’ve been working with has been inspiring. Landholders are telling us the funding enabled them to improve their habitat so it’s looking the best it has in years, and they’re proud of the importance of their place to threatened species.”

Hundreds of trees and native mat rushes have been planted along South Cedar Creek at Ravenshoe as part of a war against weeds.

Landholder Anne Evans said she felt like she and husband Ivan had won Lotto when they were approached about planting trees along a creek bank smothered in lantana and guinea grass.

“You couldn’t see the creek for the weeds a couple of months ago, so we brought in machinery to remove them,’’ she said. “Then we got a call from the council and what they were proposing fitted right in with what we were trying to achieve.”

More than 2000 trees and mat rushes have been planted along the creek bank as part of larger project that Terrain NRM and the Tablelands Regional Council are working on which began with weed removal and revegetation work in nearby council reserves bordering South Cedar Creek.

Terrain NRM’s Chelsy Maloney said the ‘Native Vegetation: Many Hands Make Light Work’ project, funded through the Queensland Government’s Natural Resources Investment Program, was improving the resilience of native vegetation in partnership with local councils.

She said weed removal was the focus for 10 hectares at Marshall Park Reserve, and revegetation work would benefit another two hectares along South Cedar Creek.

“At Marshall Park the canopy trees were there, but everything underneath the canopy was invaded by weeds. If we don’t stay on top of managing this area, it’ll lead to an irreversible change of the ecosystem.”

Tablelands Regional Council’s Cr Annette Haydon said the council was removing weeds and trialling the use of a different combination of species, to be planted in patches of the wet schlerophyll forest.

The goal was also to reduce the amount of seeds flowing downstream and causing weed infestations in other areas.

Tiny beetles could be the answer to an invasive weed that has been found in the Tablelands, Kuranda and Cairns regions.

Terrain NRM and Biosecurity Queensland recently released leaf-mining jewel beetles near Atherton to see if they can stop the spread of cat’s claw creeper – a weed that smothers rainforest and changes the chemistry of soils.

Cat’s claw was introduced to Australia as an ornamental plant. Its spread began in the 1950s and it has since been found from Sydney to Cooktown.

Terrain NRM’s Regional Agricultural Landcare Facilitator Evizel Seymour said a biological control trial using leaf-mining jewel beetles had begun along Priors Creek near Atherton.

She said 1500 beetles were released at three sites.

“If these beetles establish themselves there, the plan is to use these spots as a nursery and release beetles at other known cat’s claw creeper sites on the Atherton Tablelands,’’ Ms Seymour said.

Leaf-mining beetles and their larvae feed on the creeper’s leaves. The South American beetle was introduced to Australia as a biological control in 2012 and is considered a “proven bio-control agent”. Its effectiveness hasn’t been tested yet in Far North Queensland, where there are smaller infestations of cat’s claw creeper.

Ms Seymour encouraged Far Northerners to keep a look-out for cat’s claw.

The creeper has woody climbing stems that cling to tree trunks and it competes with native plants and trees by forming a dense above-ground mat as well as underground reproductive tubers. Its many seeds are spread by the wind and water. Cat’s claw has a yellow flower.

Yellow-bellied gliders and native frogs are on the wish-list for a degraded creek reserve near Ravenshoe that is undergoing a transformation.

Terrain NRM and the Tablelands Regional Council have joined forces to restore land at South Cedar Creek by removing guinea grass and lantana, and planting hundreds of native trees.

More than 1000 trees went into the ground recently, after spraying and brush-cutting marked the start of a four-year restoration program.

Terrain NRM’s Tony O’Malley said seven hectares was being targeted as part of a bigger project “Native Vegetation: Many Hands Make Light Work” which is funded by Terrain through the Queensland Government’s Natural Resources Investment Program, to improve the resilience of big patches of native vegetation in partnership with local councils.

Tablelands Regional Council’s Kylie Freebody said the land was in Marshall Park reserve near the top of Tully Falls Rd, and the focus was on restoring wet sclerophyll forest.

“This country is really important for quite a few species that are listed as ‘vulnerable’, as well as three endangered eco-systems,’’ she said. “We’re looking to help species like the yellow-bellied glider, greater glider, magnificent brood frog, Lumholtz’s tree kangaroo and tapping green-eyed frog.

“This land is considered an important linkage for biodiversity conservation but over the years it has been taken over by invasive weeds.”

Lantana is listed as a Weed of National Significance and guinea grass is a transformer weed which out-competes native vegetation.