Reducing weed biomass by burning and grazing can adversely affect frogs

The impacts of weed management on native biodiversity are often overlooked. Burning and grazing plots of land, in isolation and in combination, were used to experimentally reduce the biomass of introduced para grass (Urochloa mutica (Forssk.) T.Q.Nguyen)) in a North Queensland wetland. Frogs were monitored to assess the impact of these management trials. Marbled frogs (Limnodynastes convexiusculus Macleay) declined in response to all management treatments, and their abundance was correlated with vegetation biomass. The abundance of spotted marsh frogs (Limnodynastes tasmaniensis Günther) was not related to weed control treatments, but was influenced by the distance of the experimental plot from the nearest woodland. The decline of these frog species in response to management trials indicates that knowledge about impacts of planned weed control is critical, to inform management of taxa that may be affected.