Upper Mary River field day

Rhea Phalan, vector and pest plant officer, Sunshine Coast Council

Council officers, Nick Clancy, Kylie Gordon, De Attard and Luke Short attended a field day towards the end of last year. The day was organised by Land for Wildlife member Di Collier with a group of neighbours along the upper Mary River valley.

Land for Wildlife officers Nick Clancy and Kylie Gordon guided the group along the edge of a tall open riparian blue gum forest with vine forest understorey (wet sclerophyll), which is listed as ‘of concern’ under the Vegetation Management Act (Qld). Nick discussed the edge effect and how this relates to weed invasion. We then walked through the gallery rainforest (notophyll vine forest) on alluvial flats, an endangered ecosystem.

The group walked along the river, some getting to know the area for the first time, others recognising the familiar old weeping lilly pilly trees (Syzygium floribunda) they have lived alongside for many years. These stunning gnarled trees with their cracked trunks hold the creeks together and stop the land from washing into the water as the seasons cause the river to dry and drop and rise and flood. Its thick roots twine along the creek banks and sometimes fibrous parts hang in the water in matts creating shelter for freshwater fish to hide beneath.

The other impressive aspect of this ecosystem was the dense ground covering of lomandra which serves to stabilise the river banks, prevent weed invasion and is the perfect habitat for the giant barred frog (Mixophyes iteratus). The female giant barred frog uses its webbed hind legs to kick the fertilised eggs out onto the bank and the overhanging lomandras. The lomandras fringe the stream helping to shade and protect the eggs until the tadpoles hatch and drop into the water. The giant barred frog is listed as vulnerable to extinction under the Nature Conservation Act (Qld) with the key threatening process being loss of riparian habitat including these types of stream microhabitats.

The group spent some time on a small river island, which because of flooding events experiences constant disturbance. Because light levels are also relatively high here, it is the perfect spot for weed incursion. Here the group was introduced to weedy grasses, various vines, wild tobacco (Solanum mauritianum) and giant devils fig (Solanum chrysotrichum), and many other common weeds. The most threatening weeds to this particular ecosystem are those that thrive in low light such as Ochna serrulata (Micky Mouse plant), Celtis sinensis and Paspalum mandiocanum (broad-leaved paspalum). The group also talked about different methods for controlling these weeds including applying herbicide by stem scrap, cut-stump and drill and fill method and the use of tree poppers.

After a shared picnic along a tributary the neighbours were introduced to an extensive area of Celtis sinensis at various stages of growth, including some large trees that were starting to fruit. These trees are listed under the Sunshine Coast local government area biosecurity plan as a priority invasive plant with the management action for them being targeted landscape management. In a spot like this, on the upper part of the Mary River, close to Bellthorpe national park, and surrounded by several land for wildlife properties, is a good place to start controlling them. Not only will the river carry the seeds further down stream towards Kenilworth, Imbil and Gympie, but birds will also disperse them into forests nearby. Sunshine Coast Council pest plant officer Luke Short gave an interesting demonstration of some newly purchased weed control equipment; the stem injeckta (see image below). The stem injeckta allows a capsule of herbicide to be injected into the tree and is useful for controlling larger weed trees where it is safe to do so. The tree popper, that was demonstrated earlier in the day is good for taking out smaller weedy Celtis sinensis seedlings.

Council would like to thank Di Collier (event organiser), Sue Brieschke (Hinterland Bushlinks) John King (MRCCC upper catchment rep) and property hosts, Steve and Mary-Anne Burnet, Jamie Hoggess and Donna Pitkin for all the work they have been doing to look after these parts of the Upper Mary river and its tributaries and for bringing together new and old residents for this field day. We also thank everyone who attended on the day. If you would like to get started on looking after the creek in your backyard, you can download a practical guide here.

References

• Aland, K. & P. Wood (2013). Giant Barred Frog (Mixophyes iteratus) Baseline Survey. Bruce Highway (Cooroy to Curra) Upgrade Section A - (Cooroy southern interchange to Sankeys Road). EPBC Referral 2011/6024. Report Prepared for Department of Transport and Main Roads. Future-Plus Environmental
• Hines, H., M. Mahony & K. McDonald (1999). An assessment of frog declines in wet subtropical Australia. In: Campbell, A., ed. Declines and Disappearances of Australian Frogs. Page(s) 44-63. Canberra: Environment Australia. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/frogs.html.