Managing flows for frogs: wetland inundation extent and duration promote wetland-dependent amphibian breeding success

Abstract

Context River regulation is a key threat to amphibian communities that continue to face global declines. Prior work in regulated river catchments has indicated that wetland inundation from connecting river flows supports breeding in some frog species more than others. Aims Our aim was to identify flow metrics influencing breeding and recruitment success in flow-dependent frogs, to derive flow–ecology relationships. Methods We conducted repeat surveys of frog communities between 2015 and 2020 across two important wetlands in the northern Murray–Darling Basin, Australia. Using random forest analyses, we investigated the influence of 22 explanatory variables on breeding activity and success. Key results Inundation extent was the most important driver of calling activity by flow-dependent species (increasing breeding attempts), whereas the volume of river flows in the preceding months was most important for increasing breeding success. Conclusions Two key features of the flow pulse are linked to breeding success for amphibians in floodplain wetland systems: (1) the size of the pulse as it relates to area of wetland inundated; and (2) the duration of connecting flows as a measure of wetland duration. Implications By establishing amphibian flow–ecology relationships, these species can be included in governmental environmental water objectives and management.