Expansion of the sharp-snouted rock lizard (Dalmatolacerta oxycephala) in the southern part of the island of Cres

Abstract

In 2005, a new lizard species, the sharp-snouted rock lizard (Dalmatolacerta oxycephala) appeared on the island of Cres, probably due to anthropogenic transfer. Before that, only the Dalmatian wall lizard (Podarcis melisellensis) had inhabited the town of Osor, where the new species was discovered. In areas where the two species live sympatrically, P. melisellensis is competitively superior to D. oxycephala; however, in Osor, D. oxycephala appeared in parts of the town where P. melisellensis had been present before. Since 2005, there has been no systematic survey to assess how the distribution of the two species has changed in Osor and, the aim of this study is to investigate how far D. oxycephala has spread and what happened to the distribution of the native P. melisellensis after the new species appeared. Here we show that in 16 years, the native Dalmatian wall lizard was outcompeted by the sharp-snouted rock lizard, and there was no observation of the two species together at the same locations. Despite the new species preferring high stone walls, specimens were also found on shorter stone walls alongside the road towards Lošinj. According to our findings, the further spread of the sharp-snouted rock lizard cannot be excluded in the upcoming years in Cres, which could negatively affect the native Dalmatian wall lizard, but further research is needed to reveal the causes of our observations and to monitor the changes in the distribution of the two species.