Developing indices of relative abundance for monitoring cave and ground wet (Orthoptera) in southern beech forest, New Zealand

摘要

We sampled populations of forest-floor dwelling cave and ground wet using footprint tracking tunnels and spotlight transect counts in southern beech forest, New Zealand. Samples were compared to estimates of wet density based on mark-recapture estimates from 25m(2) enclosures. Both activity indices captured variability in cave wet in time and space, were strongly correlated with each other, and have the potential for monitoring cave wet activity levels. Comparisons between indices and cave wet density estimates were equivocal, as recapture rates were too low to calculate high-resolution density estimates. We also found that cave wet 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 wet 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.