Frog populations are declining world-wide, and while a great deal of attention has been paid to factors like disease, the loss of natural habitat remains the single greatest threat to amphibian populations. Despite this, we know very little about how frogs respond to habitat changes, particularly altered water regimes or how to manage wetland flooding regimes to increase their chances of survival.

 

“Given that amphibians are declining right across the floodplains we need a better understanding of the factors that affect the persistence of species, particularly nationally endangered species such as the Southern Bell Frog, and what we can do to help sort out the frog problem,” said Dr Skye Wassens from Charles Sturt University’s Institute for Land, Water and Society who is leading a two year research project, funded by the NSW Murray Wetlands Working Group (MWWG).

 

The $90,000 project “Optimising frog breeding responses to flooding in managed wetlands” is looking at the relationship between different flooding management regimes and breeding responses of wetland frogs in wetlands along the Murray from the Hume Dam to the SA Border.

 

Dr Wassens said previous monitoring of environmental wetland watering had focussed on meeting the needs of waterbirds and vegetation. “However we don’t know whether watering regimes established for waterbirds and vegetation actually meets the requirements of the fish and frogs that live in wetlands,” she said.

 

“Unlike waterbirds, frogs can’t move easily between wetlands, and many have highly specialised requirements in terms of inundation. Tadpoles are obviously very vulnerable to wetland drying patterns so for optimum frog recruitment you need the water in the wetland for a specific length of time. We just don’t know how long that should be.”

 

As part of the research, Dr Wassens and research officer Sascha Healy will be inspecting potential monitoring sites around Mildura near Wentworth and Robinvale next week. A number of the wetlands have been ear-marked for the MWWG’s environmental watering program which is to start at the end of the month.

 

Dr Wassens said the project is dovetailing with the a current Murray-Darling Freshwater Research Centre project, funded by the National Water Commission, which is investigating fish response to wetland watering and restoration in wetlands along the Murray River.