Optimising frog breeding responses to flooding in managed wetlands (i) Temporal activity patterns and selection of breeding sites

Research output: Book/ReportCommissioned report

Abstract

The selection of breeding sites and temporal activity patterns were assessed for frog communities in wetlands along the mid-Murray River. Two key types of wetlands were assessed, small ground and rain fed depressions (n=5) which varied in hydroperiod from 3-12 months and large ox bow lagoons (n=5) that had contained water for extended periods (more than 1 year prior to this study). Habitat, water chemistry, tadpole abundance and the presence of adults and metamorphs were sampled over a four day period every month for 12 months (November 2007 to October 2008) at each sample wetland. Calling activity was monitored every second day using automatic call recorders which were placed at each wetland for the duration of this study.
Four frog species were recorded; Crinia parinsiginfera, Crinia signifera, Limnodynasties tasmaniensis and Litoria peronii all of which are common and abundant through the Murray River corridor. Tadpoles were recorded at 7 of the 10 wetlands over the 12 month period. The abundance of tadpoles increased with increasing percent cover of aquatic vegetation. All four species utilised the same wetlands and had similar habitat presences but they used the wetlands at different times of the year. The two Crinia species dominated wetlands in winter and Litoria peronii dominated in summer. Calling activity was influenced by temperature with the summer breeding species more likely to call on warm days (above 200C), Crinia signifera was more likely to call on cool days. The differences in peak activity periods have implications for the timing of wetland flooding with winter flooding favouring Crinia species. Spring and summer active species may not respond to winter flooding unless wetlands remains pooled in the wetland during spring or early summer.
Tadpoles appeared in the wetlands after the peak calling periods and remained in the wetlands well after calling had ceased. Water should remain pooled in the wetland for an additional length of time after calling ceases to ensure that tadpoles have sufficient time to reach metamorphosis. It is essential that wetlands are checked for tadpoles a few months after the wetlands are flooded because a small top-up with environmental water to extend the wetland hydroperiod by a few months may mean the difference between recruitment failure and success.
Original languageEnglish
PublisherInstitute for Land, Water and Society
Commissioning bodyMurray Darling Wetlands Working Group
Number of pages29
Publication statusPublished - 2009

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