Dramatic increases in weta (Orthoptera) following mammal eradication on Maungatautari - evidence from pitfalls and tracking tunnels.

摘要: Opportunities now exist to establish pest-free areas on the mainland of New Zealand by eradicating introduced mammals from within predator-proof-fenced areas. This has increased opportunities investigate how native insect fauna responds eradication mammals. We examined response weta populations mammal in a before-after-control-impact (B ACI) experiment southern exclosure Maungatautari. A novel monitoring technique (footprint tracking tunnels) was used combination with conventional (lethal pitfall traps) monitor populations. Within 2 years after eradication, there were dramatic increases captures, rates and incidence footprinting per card (proportion squares tracked out 100). The mean number 12-fold (95% credible interval 7-20) for adult Hemideina thoracica 52-fold 30-89) other weta. Before immediately approximately equal proportions juveniles, subadult caught traps. age structure traps changed percentage samples increasing markedly 30% summer 2004/05 66% 2008/09. sex ratio also changed, females 25% 55% two techniques have different advantages disadvantages, which are discussed, but key tunnels that they non-lethal time-efficient. Counting gave more sensitive precise indicator than simply recording presence absence tracks, required much processing time.