Can we provide evidence that conservation measures are effective? 

This is the major question behind articles in the journal Conservation Evidence. Today, Andre de Villiers published a short contribution to Conservation Evidence which shows that work over the last 5 years to remove African clawed frogs (Xenopus laevis) from an area they invaded in the Cape of Good Hope. Andre's article compares populations of the IUCN Endangered Cape platanna (Xenopus gilli) in an area near Kleinmond where there is no control of African clawed frogs. He found that when African clawed frogs were removed, the population of Cape platannas was healthier. In addition, he shows that regular monitoring of African clawed frogs is necessary to prevent invasion outbreaks, which are costly to remove.