Authors: Dr Damian Michael, Gaye Bourke and Associate Professor Skye Wassens (Charles Sturt University, Institute for Land, Water and Society, Albury NSW).

The regulation of rivers and waterways has had a profound effect on biodiversity across the Murray-Darling Basin, especially species that breed in ephemeral wetlands. While the focus of environmental watering actions are often to achieve outcomes for waterbirds, fish and frogs, the benefits of environmental water don’t just stop at the water’s edge. Terrestrial species also benefit from improvements in wetland health.

Anurophagous snakes (species that eat frogs) such as the red-bellied black snake (Pseudechis porphyriacus) and the eastern tiger snake (Notechis scutatus) are common around healthy wetlands and play an important role as top predators by transferring nutrients between aquatic and terrestrial environments.

The delivery of environmental water to key wetlands may also benefit threatened and poorly known snake species. For example, the mud adder or De Vis’s banded snake (Denisonia devisi), thought to be confined to the alluvial flats in Queensland and northern NSW, made the headlines 15 years ago when it was discovered for the first time in Victoria. The snake was probably carried south during a period of flooding and then persisted due to improvements in biodiversity and habitat suitability resulting from improved water management.

It now appears this is not just an isolated case. During the summer of 2019, researchers from Charles Sturt University encountered high densities of the grey snake (Hemiapsis damelii) along the banks of several recently watered wetlands in the Lower Murrumbidgee region. The grey snake is a small nocturnal species which is listed as endangered on the IUCN Red List of threatened species. Once common north of the Macquarie Marshes, the species has declined across its range and up until recently, had not been in seen in the lower parts of the Basin for almost 30 years.

Overall, 21 grey snakes were recorded from environmental watering sites and they were all fully laden with frogs! These sightings represent the first formal records of this species in the Murrumbidgee catchment, and are the first confirmed sightings of the species in the lower Murrumbidgee region in a very long time. Improvements in frog populations and wetland vegetation are likely to have created ideal conditions for this floodplain species.

Grey snakes are among the many reptile species that may benefit from water management, yet little is known of the ecology and population dynamics of most reptiles in floodplain environments. Over the next three years, researchers from Charles Sturt University will investigate the relationship between environmental water management and reptile communities in the Murrumbidgee catchment.

Photo credit: Damian Michael

Photo credit: Damian Michael

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Our work in the Murrumbidgee

The Murrumbidgee is a lowland river system with large meandering channels, wetlands, lakes, swamps and creek lines. Our work here focuses on understanding how native fish, waterbirds, reptiles and amphibians, as well as wetland vegetation communities, benefit from these targeted environmental watering actions.

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