Vegetation mounds as over-winter Habitat for Green and Golden Bell frogs Litoria aurea

Long-term refugia or “over-winter” habitats are often overlooked in habitat restoration for the endangered Green and Golden Bell frog Litoria aurea. Studies identifying the occupation of this habitat or materials suitable to re-create it are lacking. Vegetation mounds were trialled and monitored for 26 months to determine if they could provide shelter conditions for Green and Golden Bell frogs. Covered and uncovered mounds were monitored at two sites (Arncliffe and Woonona) and both types of mounds were utilised by Bell frogs. Most frogs using the mounds for shelter remained active while inside the mounds, a few became torpid while in the mounds. The use of the mounds was influenced by ambient weather conditions. Vegetation mounds have a management advantage over other types of over-winter habitat in that they are portable, cheap and easy to maintain and easy to monitor. In addition, they provide a thermal and humidity gradient and allow frogs to move within the mound to select the preferred microhabitat conditions. As mounds temperatures are above ambient temperatures during winter, they may also assist in reducing the susceptibility of over-wintering frogs to chytrid infection. More detailed studies are needed to determine the optimal size, composition and best management use of the mounds.