Recently introduced mammalian predators have had devastating consequences for biotas of archipelagos that were isolated from mammals over evolutionary time. However, understanding which antipredator mechanisms are lost through relaxed selection, and how they influence the ability of prey to respond to novel predatory threats, is limited. The varying effects on native lizard populations of the relatively recent and patchy history of mammalian introductions to New Zealand’s islands provide an opportunity to examine the consequences of relaxed selection.
Invasive species can have negative consequences on native reptile populations, especially on island systems. Chemical control can be a cost-effective way to control or eradicate invasive species. Chemical control is currently in use in New Zealand to limit impacts of non-native mammals and plants on a range of native biodiversity. However, it is important to consider the potential non-target risks of chemical control to native species that are likely already significantly reduced in number.
Animal reintroduction is an important tool for species conservation, but success rates can be low. Comparative studies can be used to identify factors that influence success during translocations. We studied the reintroduction of captive-reared and wild-caught juveniles of an iconic reptile, the tuatara Sphenodon punctatus, on the South Island of New Zealand. We followed juveniles from three treatment groups (wild-caught and from two outdoor head-start facilities, all of the same genetic stock) during the initial five months of the establishment phase.
Anticoagulant poisons, especially the second-generation anticoagulant brodifacoum, are used worldwide to eradicate pest mammals from high priority nature sites. However, the potency and persistence of brodifacoum may present threats to non-target species. In New Zealand, most ecosystems lack native terrestrial mammals; instead, birds, reptiles and invertebrates fulfil key ecosystem roles. Introduced mammals represent the biggest threat to persistence of native species.
Understanding the factors that influence patterns of ectoparasite infestation within wildlife populations involves knowledge of the mechanisms that influence host infestation. For ectoparasitic ticks, knowing where ticks might occur in the off-host environment and how they locate their hosts is essential to understanding patterns of ectoparasite infestation. The tuatara tick (Amblyomma sphenodonti) parasitises the tuatara (Sphenodon punctatus) on Stephens Island, New Zealand.