Status of three great crested newt Triturus cristatus populations after translocation

Abstract: The great crested newt Triturus cristatus has a high legal protection in Europe through the Bern Convention and Habitats Directive, which often come into conflict with human development. Translocation of populations are increasingly being used as a “solution” to this conflict, but the implications for the populations’ status are not known. With the aim of investigating these effects, three translocated populations in Stockholm, Sweden were studied using a capture-mark-recapture method. The results show that both population size and body condition of the great crested newt can be affected by translocation. The results indicate a 90 % local population decrease for one of the populations, while the other two studied populations seem unaffected. The difference is probably due to the removal of drift fence for the population that had declined, while the drift fence remained for the other two populations. For the population that decreased, body condition increased after translocation, but was still lower compared to the other two populations. This study shows that translocation of great crested newt populations can negatively impact their status, possibly due to a strong “homing-behavior” when the drift fence around the receptor site has been removed. This homing-behavior likely persist for more than one and a half years after translocation. Further studies are needed to investigate factors that affect salamanders’ long-term population changes and body condition after translocation, including long-term effects of drift fence around the receptor site.