National Wetlands Update September 2012
Issue No. 21, September 2012
Frog numbers and diversity improve during recent floods and environmental flows in the Murray
Sascha Healy, NSW Office of Environment and Heritage
Mid-Murray wetland site where frog monitoring
occurs, November 2011. (Emma Wilson)
Frog monitoring is providing important information on the way wetlands respond to floods and environmental flows in the Murray River system.
The NSW Office of Environment and Heritage (OEH), the environmental water manager of NSW, continues its commitment to deliver environmental water to help improve and rehabilitate wetlands along the Murray River. Many benefits from the recent 2010-2011 and 2011-2012 high system flows have been observed including large waterbird breeding events, fish movement and recruitment, improved health of river red gums (Eucalyptus camaldulensis) and aquatic vegetation and frog recruitment.
OEH has completed ongoing frog monitoring of the Mid Murray and several associated creeks and the Lower Murray systems since 2009-2010. In 2010-2011 and 2011-2012 eleven frog species were identified across the system compared to the eight species detected during initial surveys conducted in 2009-2010 (Table 1).
|Frog||2009-2010||2010-2011 & 2011-2012|
|Crinia parinsignifera (plains froglet)||*||***|
|Crinia signifera (common froglet)||**||***|
|Limnodynastes dumerilii (pobblebonk)||*||*|
|L. fletcheri (barking marsh frog)||**||***|
|L. interioris (giant banjo frog)||*||*|
|L. tasmaniensis (spotted marsh frog)||***||***|
|Litoria caerula (green tree frog)||*|
|L. peronii (Peron's tree frog)||**||***|
|L. raniformis (southern bell frog)||*||*|
|Neobatrachus sudelli (Sudell's toadlet)||*|
|Uperoleia rugosa (wrinkled toadlet)||*|
* indicates frogs were detected during a survey event
** indicates numbers estimated above 100 during a survey event
*** indicates numbers estimated above 1000 during a survey event
Peron's tree frog in a Murray wetland.
The frog surveys included both visual and aural methods across habitats such as in stream habitats, floodplains and associated wetlands and ephemeral and permanent creeks. The identification of egg masses, tadpoles and metamorphs occurred opportunistically. Results from the frog monitoring indicate that during 2010-2011 and 2011-2012, environmental and high system flow events provided opportunities for adult frogs to breed, recruit and gain condition.
The high system and environmental flows during 2010-2011 and 2011-2012 have also contributed to the improved condition of riparian wetland vegetation, such as lignum (Muehlenbeckia florulenta) and submerged aquatic plants. These are used by frogs as refuge, for foraging, for males to call from and as substrates to attach eggs.
The delivery of environmental water during periods of prolonged drought is important to provide refuge habitats for wetland dependant fauna. Equally, prolonged high system flows can provide longer opportunities for fauna to breed and recruit and build up numbers and for flora to regenerate and complete lifecycles.
For more information visit NSW Office of Environment and Heritage .