Invasive populations of Xenopus laevis (Daudin) in Chile

Invasive populations of Xenopus laevis are known from the UK, USA and Chile, although there is poor documentation of the latter. Currently, four administrative Regions in Chile are reported as having established populations. Fieldwork during the austral winter of 2001 was conducted in order to assess the density and diet of X laevis populations in two localities. At one site, fewer than 30 adults were captured and a population 4 times this size was estimated. At the second site, nearly 2000 adults were trapped and a population of nearly 20 000 was estimated. This yielded density estimates of 0.37 and 0.25 clawed frogs m(-2) respectively. However, significant bias in the sex ratio of animals caught at each site suggests that the populations may be even larger. Stomach contents of a sub-sample of animals revealed a diet consisting primarily of zoobenthic and zooplanktonic components. Further work is required to assess the extent to which this anuran affects the biodiversity of indigenous aquatic invertebrate, fish and amphibian populations.