Splendid Fairy Wren, photo courtesy of Georgina Steytler

In this edition we cover:

• Inlet Update
  
• WICC explores options for green waste 
• Rainfall Update
• Western Ringtail Possum (ngwayir)
• Farmer in Focus Trevelyn Smith
• Cockies for Cockies

“Going out early in the morning for water quality monitoring during Djeran can be very special”, says Dr Elke Reichwaldt from the Department of Water and Environmental Regulation. “Some mornings are really still and mist rising from the warmer inlet water gives the inlet a magical touch.”

Since the inlet closed in the beginning of January, the water level has decreased by about 40cm because of the high evaporation in summer and the absence of any significant river flows. This decrease is similar to other years when the inlet closed early January. Visitors to Prawn Rock Channel see the large areas of sand exposed in the channel and might be surprised to hear that the current water level at -0.2 mAHD is not unusually low for this time of year. The large amount of sand and the extensive bar at the moment is not only due to the low water level, but also due to intense storm events at the end of last year that pushed a lot of sand from the ocean into the inlet and Prawn Rock Channel. 

The low water level has exposed sediment and accumulated plant material around the edge of the estuary, which is now decaying. “The smell that you notice while driving along Ocean Beach Road is from decaying organic matter, which is normal for this time of the year when the sandbar has closed that early”, says Elke. “However, with the arrival of Djeran, we expect that once we see more consistent rain in the catchment the water level will rise again and reduce the amount of exposed organic matter.”

People out boating in the inlet might have noticed that the water is currently murkier in the eastern basin than in the western basin. According to Elke, this is what we see each year around this time. “With some of the eastern rivers slowly starting to flow following recent rainfall, nutrients are washed into the inlet. Together with the warm water this encourages microalgae growth, making the water murky. The good news is that the level of microalgae growth we see at the moment is similar to previous years”. For further information, visit the Healthy Estuaries WA website: https://estuaries.dwer.wa.gov.au/estuary/wilson-inlet/

Photo courtesy of DWER

In 2022, WICC secured funding from the Department of Primary Industry and Regional Development's (DPIRD) Future Carbon Program in order to explore the feasibility of converting the Shire of Denmark's (SoD) green waste into biochar.  The SoD receives approximately 800 tonne per annum of green waste at their waste transfer station.  WICC and the SoD have partnered with Murdoch University scientists to see if we can turn this growing dilemma into a a resource.  

In this article we sit down with Murdoch's Dr Xiangpeng Gao to chat about  biochar is, what their lab work has shown and how this can all work...

Biochar

WICC: Xiangpeng, tell us about how green waste pyrolysis and any benefits to rural areas? 

Xiangpeng: Pyrolysis refers to the heating of organic matter such as garden or farm plant wastes, without any oxygen. As green waste is simply home and farm plant matter it is a renewable energy source. Commercial green waste pyrolysis usually occurs 400 – 550 °C and makes a charcoal, also known as biochar. Producing biochar from green waste offers several benefits to rural areas. These include improving soils to improve fertility, water retention, nutrient availability, and thereby crop yields. By better using green wastes to make biochar, rural areas can avoid burning it or landfilling it which reduces air and water pollution, and it also reduces greenhouse gas emissions. Making biochar from green waste can create new economic opportunities in rural areas, such as new jobs, and having a local supply of biochar saves on transport costs and emissions to supply local farms and gardeners. Because the biochar is made at high temperatures it also eliminates pathogens and weed seeds and thereby improves local sanitation and biosecurity.

Dr Xiangpeng Gao (left) and Dr Jiadong Teng (right) with the lab pyrolyser that converted green wastes to biochar

WICC: How could a pyrolysis system be used with green waste in Denmark?

Xiangpeng: The Shire of Denmark’s Waste Transfer Station alone receives more than 800 wet tonnes of green waste every year. Currently, this waste is either burned or might be transported nearly 100 km to the east of Albany for disposal. This either causes smoke emissions and safety issues from burning it, or additional carbon emissions from transportation. It is also a waste of a valuable bioenergy feedstock. By locally converting the green waste to biochar, it is possible to eliminate smoke emissions and avoid new transport emissions, and sequester the carbon in the biochar into soils for the benefit of farmers and gardeners.

WICC: How does converting green waste to biochar help climate change and farmers?

Xiangpeng: When green waste is burned or when it decomposes, almost all the carbon that was absorbed during plant growth is released as carbon dioxide. However, if the green waste is pyrolysed, only about half of the plant carbon is released and the remaining half is transformed into a very stable form of carbon in biochar. If used in soils it can improve the soil for hundreds of years as it degrades extremely slowly under natural conditions. That is why it is an effective method for reducing atmospheric carbon dioxide, locking it up in stable carbon forms in the soils as biochar for a long time. Pyrolysis of Denmark’s green waste at the Waste Transfer Station alone could produce around 175 – 285 tonnes of biochar annually, which could sequester around 395 – 643 tonnes of carbon dioxide equivalent gas when applied to farm soils. Farmers and gardeners benefit by using biochar in various ways, including using it in soils, composts, and potting mixes for improving plant growth. It is also a useful additive to animal feed to improve digestion, animal health, weight gain or milk production, and can reduce the amount of methane livestock emit. Farmers may even earn carbon credits if they wished to do so and if Australian regulation allowed it. 

WICC: How is Murdoch University ensuring biochar produced from Denmark's green waste is safe?

Xiangpeng: We produced biochars from Denmark green waste at a laboratory scale at controlled temperatures. We also characterised these biochars using sophisticated instruments such as a thermogravimetric analyser for proximate analysis, an elemental analyser for determining the contents of carbon, hydrogen, nitrogen, sulfur, and oxygen, a total organic carbon analyser for quantifying water-leachable organic carbon, and Inductively Coupled Plasma Optical Emission spectroscopy for water-leachable inorganic elements like sodium, potassium, magnesium, and calcium. The results showed us the biochar produced from Denmark green waste at 400 – 550 °C, is safe for soil application. In Europe, a voluntary industry standard known as “European Biochar Certificate (EBC)” assists biochar producers and users to ensure biochar is safe, and the EBC could serve as a guideline for Australia. At the moment Australian regulations and certifications at a State/National level are needed so people can safely use quality Australian biochar. 

A thermogravimetric analyser (left) and an elemental analyser (right) at Murdoch University used to analyse the Denmark green waste.

WICC: How scalable and cost-effective are pyrolysis units for converting a green waste resource?

Xiangpeng: Pyrolysis is a highly versatile technology that can convert green waste volumes ranging from a few to many hundreds of tonnes per day. Our recent economic analysis indicates that producing biochar from Denmark’s Waste Transfer Station green waste only (~800 tonnes per year) could be profitable after comparing the minimum selling price of biochar and the current biochar market price. With WICC and the Denmark Shire we are investigating many opportunities for Shires to work together for more cost-effectively utilising green waste, with the benefits going to local farmers, gardeners, the community, our environment, as well as being another tool to reduce global carbon dioxide emissions.

This Project is supported by the Western Australian Carbon Farming and Land Restoration Program

Rainfall for February was categorised as ‘extremely low’ to ’severe deficiency’ for our region with Mount Barker town collecting only 4.25mm.  Barker made up for it in March collecting their 113 year mean rainfall.  Denmark didn’t fair much better, however had more rainy days.  Moving ahead, April has gotten off to a decent start due to a low pressure system around the 14th that dumped 30mm to 40mm in the lower catchment and 20mm to 30mm in the upper catchment.  

Looking further ahead, our two main climate drivers are expected to ease which indicates 'a dry signal is starting to emerge’ (BoM).

By Tim Gamblin

Most south-coast folk are aware of our western ringtail possum (WRP) also known as the Ngwayir. It’s the iconic and critically endangered species that quietly and humbly goes about its business.  No raucous cockatoo cries or loud bittern booming, no quokka-like selfie stardom, or even the fierce demeanour of some our other threatened species like trapdoor spiders, chuditch or great white sharks.  You’ll usually see them either lying still on the road as roadkill or sitting still up a tree, poised like a stuffed toy, staring back at your spotlight. They remind me of koalas and sloths with their relaxed pace, mooching up a peppermint tree (Agonis flexuosa) - their favourite browsing species. It’s a simple slow life.  In the Busselton area where their well-known core population occurs, there is perhaps a bit more action with higher densities of possums. Here they contest for a spot to build a drey or compete over someone’s prized garden roses or fruit trees.  Dreys are like nests and are usually made by clumping peppy branches together, but they sometimes use sedges or grasstrees too. They are used as refuges, especially during the day or in rough weather. There might be more food and night-life in Busso compared to the quiet life in the Denmark region but there are more threats too. More traffic, people, cats and dogs, residential expansion, fragmentation of habitat, tree felling. A few years ago, I assisted in the planning of rope bridge networks across busy roads and artificial drey placement in Busselton for translocated possums – such is the complexity of managing wildlife in an urban setting. Not as much an issue down here but there are similar threats, feral predators – cats and foxes and occasionally dogs but to a lesser extent habitat fragmentation and climate change. Too frequent burning may also be an issue and as you can imagine they aren’t good at escaping fires. Reviewing of fire regimes, especially in remote bush blocks far from people and infrastructure around the Walpole Core Wilderness is important.    

Before we get too far, just for anyone new to possums, they are different from the more common grey brushtail possum ‘brushies’.  In fact, brushies outcompete them, being larger, more aggressive and not having a sophisticated palate. They don’t build dreys. WRP are smaller, darker, with shorter rounded ears and don’t have a brush like tail. WRP are a bit bigger than a school ruler and weigh a bit more than a litre of milk. They are brown on the top and cream underneath with a white-tipped tail. They don’t only live in peppy trees but certainly prefer them, and also tuart. Hence why they are found mainly around the coast. Historically they ranged from Geraldton to the Nullarbor plain, but are now in just a few patches around the southwest and south coast. Mature trees with a connected canopy is critical as it means they can move around without risking getting down onto the ground where feral predators are most likely to find them. It is a myth they only use dreys. They are known to live in tree hollows such as in mature marri.  They also eat marri and jarrah leaves. They live in a relatively small area; their ‘home-range’ is a couple of footy ovals. They usually have a single young (though can be two or three) and they come out of the pouch at 3 months. 

Photo courtesy: A. Wayne D.B.C.A.

Not knowing for certain but suspecting that WRP might occur in the Eungedup Wetland (see previous newsletters for Eungedup background), WICC’s biodiversity unit did a brief single night spotlight survey to assess presence or absence of the species in September last year.  We observed a single WRP with a spotlight, aided by a thermal monocular. A thermal monocular detects the heat contrast between cooler and hotter objects, that is it produces a thermogram pattern picture. Thus, a hot possum on a cold branch sticks out. Especially useful if the possum is on the move to escape and isn’t looking directly at you, hence you don’t get spotlight eye reflectance from your headtorch.  

Once we knew we had presence it was important to start formally monitoring this conservation significant EPBC Act, critically endangered species.  The method we chose to do this was to set up walking transects that covered the majority of Eungedup Wetland and with a focus on the area where the only WRP observation was recorded.   These are illustrated in the map shown. The five transects are far enough from each other so that a possum wouldn’t be counted twice. They would be walked 4 times a year. Each transect was walked at a steady easy pace using a GPS and pre-flagged reflective tape to stay on course. Data recorded included time of possum observation, a GPS co-ordinate (location), number, species of tree, height of observation and anything else of note.  

Possum walking transects (cyan) and observations made in Eungedup Wetland in March 2023. Note the top (northern) record in yellow included two possums side by side. 

Left, a WRP low down on a wattie (warren river cedar) in Eungedup Wetland and right, a brushtail possum on the nullaki. Photos Tim Gamblin

The results revealed observations of three possums. Two together, high in a peppermint tree and an individual low down on a wattie tree (warren river cedar) Taxandria juniperina.  The transects averaged about 500m each. The total distance walked was 2.5km, it took about 2 hrs of transect walking time but obviously extra walking and driving time between transects.  Thus, to crunch very small numbers and a tiny dataset, we get nearly one possum per 40 mins surveying time, or one possum every 800m. So far, I’ve not seen any dreys casually but have not done formal surveys looking specifically for dreys. I suspect it’s a small population of possums and connected to others in Lowlands through to Torbay and beyond. There are possums also in small populations on the Nullaki. The population size would increase closer to Albany. 

The camera monitoring program at Eungedup Wetland (see last newsletter) identified foxes in the area and it’s likely cats will be here too. As such, WICC commenced a 1080 baiting program in the area and will also start a feral predator trapping program. This will help not only the vulnerable waterbirds but also the WRP. 

By Kylie Cook

Autumn active dung beetle, Geotrupes spiniger

Trevlyn Smith runs a cattle farm near Forest Hill with her husband Graeme, is a teacher at the Mount Barker Community College and is raising three kids.  The Smith family are implementing some innovative solutions on their farm with an equal eye on the environment and production.  WICC caught up with Trevlyn to find out how she pulls it all off…

WICC: Before we start, I have to ask – how you do it all?

Trevlyn:  I do what I do and the rest just has to catch up.

WICC: So, can you tell us a bit more about your property? How long have you been farming and what are your plans?

Trevlyn: We have been farming our current property for just over a year. We were down at Marbelup before that where my husband had farmed for over 30 years, breeding cattle. We bred Hereford and then we changed to Red Angus. We’re continuing with the Red Angus, we have stud Red Angus cattle as well as we run a commercial herd, using our own bulls over our commercial herd. The children are very involved.  My son Sean has his own Shorthorn stud and this year one of our daughters has started her own Simmental stud.

WICC: That’s great, did your kids naturally pick up those skills just watching you? 

Trevlyn: I suppose they have always been around it, so it comes naturally to them.  They are now making decisions, working out breeding. It gives them that responsibility and ownership of what we do on the farm. It’s no longer just Mum and Dad running the farm. They all have a focus now within the farm which is really good.  

WICC: What are your focus areas on the farm at the moment?

Trevlyn: We are very much wanting to improve our grazing management and pasture quality, so looking to improve the density of our pasture and how we graze it to get maximum benefit.  We want to incorporate the dung beetles into the program, making sure that we are looking after the environment as much as getting good production out of it.

WICC: Dung beetles are a real win-win.  We recently set up a newly imported Tasmanian autumn-active species on your farm and at the Mount Barker Community College.  How are the breeding colonies going?

Trevlyn: Really good actually. They're really cool to check and monitor on a regular basis to see what they're doing with the dung; they're really active. They slowed down for a little bit and then they got really active again recently.  They're so much bigger than the ones that we've previously got over here, they make big holes.

WICC: That’s great.  The kids at the college are getting into it as well?

Trevlyn: Oh, absolutely. They help us go collect the feed source and care for them. It's really interesting to see kids going, oh no, they're horrible, and then watch their opinion of them change as they observe and care for them.

WICC: I hear you also make your own biochar to feed to the cattle. Is that right? 

Trevlyn: Yeah, absolutely. It’s a bit of a trial to see how we go with it. We have lots of trees and prunings on the farm. I try to keep everything that we have on the farm, to stay on the farm and use our resources as efficiently as possible. Making the biochar is such a simple way to utilise all those tree branches and return them to the soil. Once I make the biochar, I then crush it up and put a bit of molasses with it, and then provide it as a free choice for the animals.  We put it in a container and it's up to them whether they eat it or they don't. And it's really interesting to see how they make the effort to go over and get it themselves.  What they don’t know is it give them all of that surface area in the rumen for all of those microbes to live off of.  It then goes through their system and into the soil. And it's great that the dung beetles take it down into the soil. 

WICC: You also have donkeys on your farm.  How did that come about and what do you do with them?

Trevlyn: My mum bred donkeys, so they came from her.  They are more of a companion for the kids at the moment. My girls love horses, but I'm not a horse person, so donkeys are the next best thing. We haven’t mixed them with the cattle yet. They are meant to be good to let in with the young bulls to stop them from fighting, but at the present time, I’m just happy for them being a companion animal for the children to work with and build up their skills and resilience.

WICC: We recently did a holistic management course together. How did you find that?

Trevlyn: Absolutely fantastic course.  It really changed how I look at a lot of things. It's definitely made me a lot more observant. I'm constantly looking at what's going on, what's happening with the pastures, what's happening in the environment around me. How things are changing and so it has definitely changed how I look at things. A big highlight was learning how I can rest our pastures and look after them better.

WICC is looking for landholders whom are interested in preserving black cockatoo habitat on their property.  We have published an Expression of Interprets which you can complete on our website.  Learn more below...

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