Differences in Establishment of Host and Parasite After One Decade Among Four Simultaneous Translocations of a Long-Lived Reptile

Abstract

Translocations are increasingly used to restore populations, yet seldom are simultaneous over large climate gradients into different latitudes, and rarely consider both a host and its parasites. Tuatara (Sphenodon punctatus) is a long-lived reptile endemic to Aotearoa New Zealand (NZ). Once found throughout NZ, tuatara populations are now sustained on offshore islands and increased through translocation, including to pest-free sanctuaries. Here, we study the simultaneous translocations of adult tuatara to four mainland sanctuaries a decade following release, investigating populations established both north and south of the founding population that span nearly 1000 km in latitude. We compared changes in body condition and snout-vent length (SVL) of tuatara, and abundance of a host-specific, ectoparasitic tick for tuatara among sites, plus evidence for survival and emergence of the next generation of tuatara. We found a general increase in SVL and maintenance of body condition between release in 2012 and 2023 at all sites, with some differences between males and females. However, tuatara at some sites showed more growth and/or higher body condition by 2023, particularly correlating with site temperature. Although ticks persisted on founding tuatara, there were fewer ticks on the next generation and those at the southern site. Evidence for a second generation of tuatara was also weakest at the southern site. This study shows that long-distance translocations north and south of a source population can yield promising outcomes for survival and growth of a long-lived reptile in current climates, though with differences in outcomes among sites.