From local rivers to Sydney’s Macquarie University – three Mamu Rangers and Terrain NRM’s Alicia Buckle recently took a deep dive into the science behind environmental DNA.

Environmental DNA (eDNA): What is it?

Environmental DNA, or eDNA, is changing the way we monitor ecosystems and it’s particularly useful in places where traditional monitoring would be dangerous (because of crocodiles) or would cause too much disturbance (in sensitive ecosystems or for rare and endangered species).

It’s being used for many things – from detecting pest fish like tilapia in our creeks and rivers or seeing whether polluted waterways are becoming healthier to monitoring endangered swordfish or finding crown-of-thorns starfish before they mature and cause major problems on the Reef.

Local waterways: How eDNA sampling helps

For Mamu Rangers, eDNA analysis is helping to monitor culturally significant species without land managers having to spend countless hours searching for them, or installing cameras and traps.

“We are using eDNA sampling to help us determine whether species like gudgeon, barramundi and mangrove jack are present or absent in waterways,’’ Mamu Ranger Francis Joyce says. “From there we’ll look at how to manage our waterways better for them.

“Being at the laboratory was amazing – it gave us more of an appreciation of all the science that happens after our sampling, and why our project’s design and sampling methods are so important.”

Fast Facts: eDNA in the laboratory

DNA is in the biological matter in samples.

Molecules called primers are released into the mixture and they attach to target sections of the DNA strands.

These sections can be used as a ‘barcode’ (like we have on products at a supermarket).

Many copies of the barcode sections are made.

These samples are sequenced to look at what species are present. Just like at the supermarket checkout, DNA barcodes can be matched to species in a database to give us a list of animals and plants found in the sample.

Microplastics are now being monitored on beaches and in rivers and creeks in the Innisfail region as part of a larger project focused on improving the health of waterways.

Mamu Indigenous Rangers will be testing for microplastics at a number of sites, sharing their results with a national program and, where they can, looking for solutions to reduce plastic pollution.

What are microplastics?

Microplastics are plastics that have broken up into very small particles in the environment, as well as plastic products like microbeads which are used in a range of cleaning, cosmetic and personal care items, or microfibres shed from clothing and other textiles like fishing nets.

Mamu Senior Ranger Francis Joyce said plastic pollution was one of the issues listed by traditional owners at community meetings last year when planning began for the waterway health project, which is being delivered in partnership with Terrain NRM.

Rangers have recently received training from AUSMAP, the Australian Microplastic Assessment Project team which records data collected by a network of researchers and citizen scientists to create a map of microplastic pollution hotspots around Australia. The information is helping to regulate industries and enabling communities and governments to develop better waste management systems.

“We’ll be setting up sampling areas, sieving sand, counting and categorising plastics,’’ Francis said.

Tracking plastics to their source

“Hopefully, further down the track, this data can tell a story. There’s also potential to track plastics to their source if a lot of the same kind of microplastics are detected.”

The Mamu Healthy Waterways Project includes monthly water sampling across the Johnstone River catchment, testing for nutrients, pesticides and suspended solids.

A new reef water quality program has been announced to reduce the runoff of dissolved inorganic nitrogen (DIN) from farms in the Tully and Johnstone catchments. The $10.7 million program will deliver a range of projects – from helping farmers with nutrient management planning, installing constructed wetlands and expanding local scale water quality monitoring.

The program is being managed by Terrain NRM and funded by the partnership between the Great Barrier Reef Foundation and the Australian Government’s Reef Trust.

Charles Hammond, Waterway Health Leader at Terrain NRM, said the Tully and Johnstone catchments are priorities for DIN runoff due to high rainfall, intensive agriculture on the coastal plain and short sharp rivers.

“There has been significant investment in these catchments previously and farmers have been working hard to improve water quality,’’ he said. “This program will continue to support farmers to make changes to land management and farm practices.

Mr Hammond said four organisations would be delivering on-ground projects.

A partnership led by Canegrowers Innisfail is addressing nitrogen losses by providing extension support to farmers to develop nutrient management plans, identify crop constraints, improve nutrient use efficiency and refine nitrogen inputs.

A boggy spot on a Mourilyan cane farm has been converted into a high-performing “constructed” wetland, removing more than 90 per cent of nitrate from water in the system. 

The Wet Tropics Major Integrated Project team has worked closely with wetlands experts and a third-generation cane farmer to transform the low-lying and unusable strip of land into a water treatment system on his 101-hectare property. 

The 1.2 hectare wetland is proving that, with some remediation and construction, low-lying wet areas can effectively remove high levels of dissolved inorganic nitrogen from the water. 

Acting Project Manager Fiona George said this wetland shows the potential of wet areas on farms to improve the quality of farm run-off water. 

“This constructed wetland is evidence that a wet piece of marginally productive land can yield excellent water quality outcomes with the help of a tailored design and relatively minimal earthworks,” Ms George said. 

“We enhanced existing features that helped it to perform as a denitrifying wetland.” 

Vegetation uptake has been a key factor, with a thriving ecosystem of plant life establishing itself in a short timeframe and enabling the denitrification process to occur. 

The Wet Tropics Major Integrated Project has trialled a range of catchment repair systems in the Tully-Innisfail area, including seven different bioreactor designs, a landscape wetland, three in-drain wetlands, a high-efficiency sediment basin, three constructed wetlands and a riparian revegetation site. 

The constructed wetlands are yielding the best results, proving that, with improved hydrology and the appropriate amount of vegetation, they have high potential to reduce nitrate levels.  

Fifteen thousand young trees are sinking their roots into Tableland soil as part of a $2.3 million project to fight erosion, improve farming land and better protect the Great Barrier Reef.

Graziers are working with Terrain NRM to repair eroded creek banks.

“Trees are the long-term solution, and they work well when they are combined with earthworks in the worst erosion hotspots,’’ Terrain project manager Vanessa Drysdale said.

“Root systems hold banks together and slow water down in heavy rain events, decreasing the chances of topsoil loss and of further erosion.”

Ten thousand trees were planted in March and April, bringing the total to 15,000 since the project began three years ago.

Ms Drysdale said the latest batch of trees went into the ground at two cattle properties with waterways feeding into the Johnstone River. A new cattle crossing was installed at one of the properties and sections of streambank were fenced off at both spots to prevent more erosion while the trees gain a hold. New off-stream watering points were also installed.

The work follows creek-side revegetation projects last year at two Tableland properties – in a landslip area at Jaggan and along an eroded creek system at Malanda.

Creek banks and the community are benefitting from a project that will plant 33,000 trees in the Tully, Johnstone and Russell catchments by the end of the year.

The Johnstone River Catchment Management Association, Johnstone Region Landcare Group and Terrain NRM are working together to deliver the $520,000 project, funded through the Queensland Government’s $10 million Reef Assist program.

The benefits of the project extend beyond the on-ground revegetation work with fifteen local people also gaining training and employment through the project.

Mourilyan local Ashlea Hepburn sees the work as an opportunity to work on country and further her skills in environmental management, a field she would like to explore in tertiary studies.

“This job gives me a huge amount of satisfaction, because I know I’m making a difference and improving the health of the environment.”

“I’m interested in studying environmental management and psychology, so this job is allowing me to gain experience in land management and work with a range of community members to achieve outcomes for country,” Miss Hepburn said.

Youth and Traditional Owners are amongst the team of local people employed, with thirteen receiving classroom-based training in cultural awareness, riverine processes, species selection, weeds, and crocodile awareness.

Fay Falco-Mammone from the Johnstone River Landcare Group is leading the on-ground works for the project and believes the benefits of land restoration projects are far-reaching.

It’s more than a job to the people in our team, they’re involved in something that’s helping the environment and they’re learning a range of skills – in teamwork, problem-solving and resilience.”

“Working in wet and muddy conditions can be testing at times, but our crew are committed to getting the job done and gain satisfaction in knowing they’ve completed the task.”

Rock work and grasses are replacing erosion on a cattle property near Innisfail as part of a $2.3 million project to improve the land and better protect the Great Barrier Reef.

More than 200 tonnes of rock has transformed two sites on the Loudon family’s East Palmerston farm, where changes to cattle and pasture practices are also making a difference.

Stuart Loudon said the property, on Berner and Fishers Creek, had been farmed by the family since the 1960s. “It’s hilly land and when it’s wet, it’s really wet,’’ he said. “We’ve been working on improving the soil, our pastures and the land so it can better handle our cattle and the wet seasons.”

The third-generation grazier has welcomed recent earth and rock work by Terrain NRM at a creek crossing and on an eroded hillside.

“The crossing area had eroded over time because of a natural spring bubbling up out of the ground above the creek in the wet season and the ongoing cattle and farm vehicle traffic,” Terrain’s Vanessa Drysdale said. “It’s the only way to access another section of the farm so we’ve laid a rock bed that’ll get cattle and traffic over soft ground without causing more erosion.”

Ms Drysdale said a gully head was forming beside a sloping pasture on another section of land where cattle once moved between paddocks. “Water was running down the cattle pads in the wet season and being funnelled into the rainforest at a gateway, causing more and more gully erosion,’’ she said. “We’ve created a bowl-shaped area and a bund so that the water spreads out over a much wider area on its way to natural waterways and doesn’t make its way to the gully head anymore.”

Mr Loudon is following up with more fencing, to keep cattle off creek banks and create another paddock for rotational grazing. He said a shift to more natural pasture enhancers was also helping to improve the land.

“We don’t use a lot of fertiliser here anymore – we’re applying a fair bit of fish emulsion and worm juice,’’ he said. “We’ve been doing that for about four years and we’re seeing healthier soil and thicker grass.”

Teams of tree-planters are helping to fight hillslope erosion on Tablelands properties in a boon for farmers, the Johnstone River and Great Barrier Reef.

Millaa Millaa graziers Elizabeth, Bruce and Gordon Carcary are among the numbers opening their gates to revegetation crews as part of a $2.3 million project focused on erosion hotspots in the Tablelands-Innisfail region.

Five thousand native trees were planted at the Carcary’s grazing property this week in a landslide area, and 2000 trees, shrubs and grasses went into the ground along an eroded creek system on a Malanda property.

Mrs Carcary welcomed the helping hands of Terrain NRM staff and its service provider NQ Land Management Services.

“This was a timely opportunity for us – we have an 80m long, 50m wide landslip that happened after two to three days of heavy rains a couple of years ago,’’ she said. “It’s on steep land that we fenced but it has been needing stabilisation to the stop more land falling in and topsoil washing away.”

Terrain NRM’s Jen Mackenzie said historical clearing of steep rainforest country for grazing had created landscapes susceptible to erosion. The two tree-planting projects will, each year, prevent an estimated 200 tonnes of sediment from flowing into the Johnstone River catchment and out to the Great Barrier Reef.

“Trees are a very cost-effective way of stabilising soil and the most economical way to deal with these two sites based on their physical characteristics,’’ Mrs Mackenzie said.

“We look at erosion on a site-by-site basis. On one property we installed rock structures known as Zuni bowls to solve gully erosion, and we’ve put in creek crossings on another property to stop erosion caused by cattle and vehicles. We’ll be working with these graziers over three years.”