We sampled populations of forest-floor dwelling cave and ground wētā using footprint tracking tunnels and spotlight transect counts in southern beech forest, New Zealand. Samples were compared to estimates of wētā density based on mark-recapture estimates from 25 m 2 enclosures. Both activity indices captured variability in cave wētā in time and space, were strongly correlated with each other, and have the potential for monitoring cave wētā activity levels. Comparisons between indices and cave wētā density estimates were equivocal, as recapture rates were too low to calculate highresolution density estimates. We also found that cave wētā counts had a curved relationship increasing with temperature, and a negative relationship with increasing shrub and woody debris cover. Based on these preliminary results, tracking tunnels could be a viable method of monitoring cave wētā as they appear more efficient than transect counts and are relatively inexpensive. However, further calibration trials are needed to determine if indices mirror robust population density estimates. ARTICLE HISTORY
In New Zealand, the toxin sodium fluoroacetate (compound 1080) is used to reduce numbers of introduced brushtail possums (Trichosurus vulpecula) to enhance forest condition and reduce bovine tuberculosis (Tb) infection in livestock. However, there is concern that the use of toxins may cause mortality in non-target species. We investigated the effect of possum control using aerially applied cereal baits containing 1080 on 36 radio-tagged South Island fernbirds (Bowdleria punctata punctata) in winter 2010. During monitoring, five fernbirds dropped their transmitters, one was killed by a predator and three died of 1080 poisoning (a mortality rate from 1080 poisoning of 9.4%, 95% CI 0 2.4Á22.6%). This study suggests that acute impacts of aerial 1080 operations on fernbird numbers are small and the observed impact could be outweighed by improved productivity and survival resulting from the reduction of impacts caused by introduced mammalian predators that die from 1080 poisoning.
Artificial retreats are increasingly being used as a tool for monitoring lizard populations in New Zealand. However, relationships between placement of retreats and skink sightings are not well understood. We investigated how microhabitat around and under artificial retreats influences sightings of common skinks (Oligosoma polychroma) in a grassland habitat in Fiordland. Our dataset comprised 2356 skink sightings from 4100 checks of artificial retreats. Mean vegetation height 0.5 m from retreats was positively correlated with skink sightings, but we did not detect relationships between other microhabitat variables and skink counts. Greater vegetation height may provide enhanced habitat complexity, thus supporting a richer faunal community and higher skink density. Alternatively, skink basking opportunities may be more limited under taller vegetation, making nearby artificial retreats more attractive for their thermal properties. We highlight the importance of considering microhabitat when placing artificial retreats to maximise detections of lizards.
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