Helen Truscott, PhD Candidate with Charles Darwin University.

With a group of high school kids looking expectantly from the edge of the swamp we slowly made our way in the aquatic UTV towards the net set the day before.

Environmental research in a small Aboriginal town becomes a community process and this research came from the community itself. In the small remote town of Ramingining in northeast Arnhem Land in the Northern Territory traditional harvesters of the freshwater species, the Northern long-necked turtle (Chelodina rugosa) began to ask the question “are there less turtle than before or are turtles just harder to find due to all the damage from feral water buffalo?”

Long-necked turtles are typically harvested in the dry season during aestivation. When they are buried in the mud waiting out the drier months till the onset of rain and conditions are favorable to reemerge. Feral water buffalo (Bubalus bubalis) were first introduced into the NT in mid-1800’s in early colonization attempts and are now widespread across Arnhem Land where numbers are increasing. Buffalo dramatically alter the same wetlands inhabited by long-necked turtle. In the dry season buffalo pugging dramatically changes the surface of the mud on dried flood plains and billabong edges where people have traditionally searched for sign of aestivating turtle. This makes it hard to understand whether the decreased turtle harvest numbers are due to difficulty in locating the species amongst the altered surface or if populations are declining due to the degradation of wetlands.

Working with the local Aboriginal ranger group the Arafura Swamp Rangers, I was present many times this question was asked “are there less turtle than before or are turtles just harder to find due to buffalo”.  I saw an opportunity to use my background in turtle research with my ongoing mission to halt increasing damage from feral water buffalo to wetlands in the wet dry tropics and particularly the globally significant Gurruwiling (Arafura Swamp), an area that over four years of work has become very close to my heart. Gurruwiling is the largest wetland in Arnhem Land and the largest paperbark swamp in Australia at over 1000 square kilometers with its catchment extending from Castlereagh Bay to the upper reaches of the Girder River.  It is a biodiversity rich area known for its distinctive Corypha utan palm and is an important breeding ground for key NT species such as the magpie goose (Anseranas semipalmata) and saltwater crocodile (Crocodylus porosus). The area is freehold Aboriginal Land with unbroken ownership and management by the area’s 27 clans. My research is looking at the characteristics of C. rugosaaestivation that may increase the vulnerability of the species to impacts from buffalo, the impacts of soil modification on aestivation success and the population structure and trends of the local turtle populations. The project is a partnership between myself as a Charles Darwin University PhD candidate and the Arafura Swamp Rangers Aboriginal Corporation.

So, I find myself bundled into the aquatic UTV traversing somewhat cautiously through one of the NT’s main breeding grounds for saltwater crocodiles.

Past magnificent water lilies, fighting off mosquitoes and in awe of the beauty of Gurruwiling heading towards a fyke net we set the day before. We reach the net and success! We have one specimen and a range of small by-catch. Ranger Narelle and I carefully retrieve the net and the turtle. Then ranger Charlie heads us steadily back to shore, which all are happy to reach.

The reason we have a group of school kids eagerly waiting is the rangers and I had given a talk at the local high school the week before on the project and we had asked if anyone was interested in getting involved and the answer was a definite yes.

I am using the fyke nets to collect data in areas where traditional harvest doesn’t often occur and therefore data that can’t be gathered from harvested turtles. This will aid in building a more complete picture of local population trends and connections. DNA analysis is just one of many methods being used to answer research questions. Much of the work is being undertaken by accompanying traditional harvesters, miyalk (yolngu women) to obtain information on aestivation characteristics, micro and macro habitats, and population demographics. Further work is being done using buffalo exclusion plots we have erected over a range of habitats looking at how the feral may modify soil properties needed for successful turtle aestivation. The knowledge gained will not only aid in the ongoing preservation of the species and buffalo management but will empower local people in partnering in research and setting research agendas on their country.

Back on shore and the school kids help in identifying and counting the macroinvertebrate by-catch and collecting weights and measurements from the turtle. The Learning on Country Coordinator uses the opportunity of an engaged class to teach measurements and writing in an area facing the challenge of low literacy and numeracy rates.

So far in the first year of my research as well as partnering with the Arafura Swamp Rangers, the project has involved elders, school children, and families, everyone working together to save a culturally significant and locally important species, the Northern long-necked turtle.  

Helen Truscott was recently awarded a Holsworth Wildlife Research Endowment grant to help support this research.   

Images (tope to bottom):

Fyke net set on Gurruwiling (Arafura Swamp) in northeast Arnhem Land to collect Northern long-necked turtle to collection population data. Credit: Helen Truscott.

Installation of water buffalo exclsuion plot by Arafura Swamp Rangers on the coastal flood plains of Castlereagh Bay in northeast Arnhem Land, NT. Credit: Helen Truscott.

Ramingining high school kids helping Helen Truscott and ranger Narelle Bonson in process a turtle trapped using fyke near Murwangi on Gurruwiling (Arafura Swamp), NT. Credit: Chrystal Burgher.