Occupancy, Abundance, and Summer Ecology of the Western Tiger Salamander (Ambystoma mavortium Baird) in the Beaver Hills, Alberta Open Access

[摘要] The western tiger salamander (Ambystoma mavortium Baird) is a ;;species of special concern’ in the Canadian prairie provinces. Potential declines caused by habitat loss and fragmentation, emergent diseases, and fish stocking are reasons cited for this species conservation status. However, little data exist about the ecology, distribution, and abundance of this species in Canada, where the species reaches the northern extent of its global range. In the Beaver Hills of Alberta, I examined occupancy, abundance, and summer habitat of the western tiger salamander. In 2013, I surveyed potential breeding ponds for salamander occurrence and abundance and characterized the distribution of populations in relation to terrestrial habitat variables with generalized linear regression. In 2014, I conducted season-long capture-mark-recapture (CMR) studies at three study sites to characterize seasonal activity patterns of adults and larvae and population sizes. I then compared CMR density estimates among sites to relative counts observed during my low-intensity survey method to determine if counts from low-intensity surveys suitably characterized salamander population densities among sites. In 2013 and 2014, I tested the effect of baited funnel traps on adult and larval capture success, as ambystomatid salamanders are difficult to detect. The distribution of salamander populations was significantly related to northern pocket gopher density (Thomomys talpoides Richardson) adjacent to wetlands, but not land cover composition. Density when present was not significantly related to any terrestrial habitat features. Counts (from low-intensity surveys) accurately characterized population density, although density estimates were very imprecise. Seasonal pond-use patterns indicate that post-metamorphic individuals remain in wetlands to forage after breeding, which is atypical among ambystomatid salamanders. Lastly, baiting funnel traps did not affect capture success of post-metamorphic individuals, but light-baited traps captured significantly more larval individuals than non-baited traps. The key findings of this study are that salamander populations likely depend on small mammal burrows to overwinter and that wetlands are important summer habitat for post-metamorphic individuals. Further, baited minnow traps differentially affect distinct life stages of western tiger salamanders, and likely other ambystomatid salamanders.

[发布机构] University of Alberta

[效力级别] occupancy modeling