The recent rain event in the Bellingen Shire has allowed a collective sigh of relief. River levels have finally risen. But what of the health of our river systems? Will there be greater sediment run-off into our waterways due to recent drought conditions and bushfires? Who is monitoring the health of our river catchments and biodiversity?
Rest assured that there is a group of steadfast warriors comprised of local community scientists in partnership with the broader scientific community who continue to monitor the health of our river systems and have done so since the mass death event of the critically endangered Bellinger River Snapping Turtle (BRST) in early 2015. At that time there was a loss of an estimated 90% of the wild population.
Bellingen Riverwatch was created in 2015 to provide consistent water quality data in the Bellinger and Kalang catchments. Bellingen Riverwatch engages 32 local community volunteers and 5 schools to collect monthly water quality data at 24 sites every month across the Bellinger, Never Never, and Kalang Rivers.
But the most remarkable aspect of Bellingen Riverwatch is the strong partnership collaboration between so many bodies that has allowed such stringent assessment of our river systems to continue. Bellingen Riverwatch is an initiative of OzGREEN and The Department of Planning, Industry & Environment (DPIE) in partnership with Bellingen Shire Council, NSW Waterwatch, Western Sydney University, Taronga Zoo Sydney, Bellinger Landcare, Earthwatch Institute, Eco Logical Australia, North Coast Local Land Services and Jaliigirr Biodiversity Alliance.
But what do we now know about the health of the endangered Bellinger River Snapping Turtle five years after the mass death event? Gerry McGilvray is Project Coordinator of the Bellinger River Turtle Recovery Project for the DPIE and has worked in partnership with Bellingen Riverwatch for the past 5 years.
Gerry, how did your partnership with Bellingen Riverwatch come about?
The NSW Government’s Saving our Species (SoS) program, led by the NSW Department of Planning, Industry and Environment (DPIE), has so far invested over $300,000 in the conservation of the Bellinger River Snapping Turtle.
In 2015 after the mortality event impacting upon the Bellinger River Snapping Turtle, the Department were approached by OzGREEN with a proposal for a citizen science program to test water quality in the Bellinger catchment. There was some community concern about the water quality in the Bellinger River and its potential influence on the health of turtles.
The SoS program provides financial support to the Bellingen Riverwatch program. The Riverwatch program is coordinated by OzGREEN with support from DPIE Science. The Department also funds the biannual testing of the Bellinger catchment by DPIE scientists for baseline water quality monitoring.
Can you describe your ongoing role as Project Coordinator of the Bellinger River Snapping Turtle Recovery Project?
I work in the role of Project Coordinator in partnership with my colleague Shane Ruming.
We are responsible for coordinating all the recovery of the BRST. This includes:
- The emergency transfer of a small insurance population into quarantine facilities in 2015, followed by the collection of a second insurance population in 2016.
- The management of breeding and insurance populations in captivity (overseen by Taronga Zoo and Symbio Wildlife Park) to contribute towards breeding a recovery population.
- The coordination of an expert reference group of wildlife disease experts, translocation specialists, zoo professionals, turtle experts, aquatic ecologists, local experts. This includes development of Conservation Action Plan which guides conservation activities.
- Coordination of a riparian restoration program and the Bellingen Riverwatch program to improve riverine habitat.
- Trial release of a small number of turtles from the captive breeding program back into the Bellinger River to supplement the wild population. This includes continual monitoring of health and disease status.
- Monitoring of the wild turtles in the river to provide population estimates of both the Bellinger River Snapping Turtle and the introduced Murray River Turtle.
- Genetic studies of the turtle populations to estimate the degree of hybidisation that occurs between the two turtle populations and examination of risk of this to the recovery of the BRST.
- Community engagement activities to increase the awareness of the conservation program.
- Support for the PhD research into the Bellinger River Virus (BRV) by the Department of Primary Industries (DPI).
- Support for a PhD candidate completing studies of population dynamics of the two-turtle population in the Bellinger River.
Was the ‘mortality event’ in 2015 related to the health of the Bellinger River?
Since the mortality event a disease investigation has identified a virus (Bellinger River Virus or BRV), previously not known to science, as the agent most likely to be responsible. It appears that the BRST was the only species affected at the time. In particular, the co-occurring Macquarie River Turtle was not affected.
The three interacting factors that influence disease are the host, the infective agent and the environment. It may be possible that there were some environmental factors that influenced the spread of the virus or had some impact on their susceptibility, but it is not evident at this stage and we will not know more about that until further research is conducted by DPI into the virus.
What is the current health status of the Bellinger River Snapping Turtle population?
The health status of the BRST population was last examined in November 2019 as part of our biannual surveys of the Bellinger River. During these surveys’ turtles are captured, measured, weighed, examined and swabbed for presence of the Bellinger River Virus.
As part of the surveys, a veterinarian from the Department of Primary Industries (DPI), Kate Parrish, is usually present to sample for the virus.
There has been no evidence of disease in the Bellinger River Snapping Turtle since the mortality event in 2015 and the remaining wild turtle population is generally considered in good health. Previous virus testing results has indicated the possible ongoing presence of low levels of virus in the river system therefore it is still important for the community to maintain good biosecurity practices (“keep it clean routine”). This includes washing down watercraft and swimmers between areas in the Bellinger Catchment and when moving between catchments.
This Summer Bellingen Riverwatch has driven the ‘Help Our Rivers Thrive’ Campaign. What was the aim of this campaign?
The ‘Help Our Rivers Thrive’ campaign facilitated by Bellingen Riverwatch is aimed at raising awareness about what the community and visitors to the area can do to maintain and improve the health of the Bellinger catchment.
These actions include:
- Cleaning watercraft and swimwear prior to visiting other areas withinthe Bellinger catchment or visiting other catchments. This helpsminimise spread of aquatic weeds and diseases
- Using toilets prior to visiting areas without facilities along the river
- Removing weeds in the riparian zones
- Using minimally polluting sunscreens
- Collecting litter.
How would you describe the current health of our local river system?
(Answer provided by DPIE water scientist Adrian Dickson)
Results from the biannual DPIE river health monitoring project, which commenced in autumn 2017 and focuses on the freshwater reaches of the system, indicate the Bellinger River water quality is generally good and typically within the nationally accepted guidelines for the region. Water temperature is seasonally influenced, as expected, and pH and electrical conductivity (salinity) are within the natural ranges expected of well vegetated coastal catchments of NSW. Turbidity and total suspended solids (TSS) have generally been within guidelines and the clear water that is characteristic of the Bellinger, has prevailed. Although there were some isolated turbidity spikes associated with rainfall/runoff events especially in the mid-catchment where human activity, such as roads (fords), agriculture and rural and urban residential areas have disturbed the natural land cover.
DPIE have been monitoring dissolved oxygen, which is a water quality parameter of concern following bushfires, in the upper catchment. Data loggers were deployed in September 2019 to gain an understanding of the daily and seasonal fluctuation of dissolved oxygen within the river, and to determine if the point sample data collected by DPIE and Riverwatch, is accurate and representative of the conditions within the waterway. This monitoring will be continued over the next few months and additional monitoring will also include dissolved oxygen in the Bellinger River estuary, with a focus on examining changes to water quality that may occur as a result of rainfall and sediment input from burnt areas.
Has the Bellinger River Snapping Turtle population started to grow again?
The population of BRST was severely impacted by the mortality event, with the loss of an estimated 90% of the wild population. As a result, the surviving population is estimated to be approximately 200 animals. Adults appear to have been more severely impacted by the disease and the remaining population is mostly juvenile or sub-adult turtles that are not of breeding age yet.
No natural growth of this population is expected for some years. In the meantime, we are trialing release of captive bred animals from Taronga Zoo’s breeding program. Since November 2018, 20 captive-bred juveniles have been released into the Bellinger River. Once the trial is complete, it is hoped that more captive bred animals can be released to supplement the wild population. In the longer term, it is hoped that released animals will assist the recovery of the BRST population to pre-2015 estimates (between 1600-4500).
So how can our community contribute to the health of this species going forward?
Successful long-term recovery of the Bellinger River Snapping Turtle in the wild will not be possible without a healthy, functioning river network within the Bellinger catchment.
By following the tips from the ‘Help Our Rivers Thrive’ Campaign, the community can help improve the habitat in the Bellinger River and the other waterways within the catchment. This in turn will provide benefit for the Bellinger River snapping Turtle as well as the myriad species that depend upon the river.