Meeting Abstract
Site fidelity has been widely reported in metamorphosed amphibians, but less is known about larvae and paedomorphic adults. Fully aquatic morphs of the Arizona tiger salamander, Ambystoma tigrinum nebulosum, occupy sup-alpine ponds with heterogeneous thermal profiles in the Colorado Rockies. Aquatic morphs of A. t. nebulosum are confined to permanent ponds; terrestrial morphs are known to move between permanent and semi-permanent ponds throughout the summer months. We studied within-pond site fidelity of PIT tagged juvenile, paedomorphic, and metamorphic Arizona tiger salamanders in five permanent and four semi-permanent ponds near the Rocky Mountain Biological Laboratory. Shallow, relatively warm regions near the perimeter of the permanent ponds, referred to as thermoregulation zones, were mapped due to apparent clustering of A. t. nebulosum. We found that both aquatic and terrestrial morphs of A. t. nebulosum do exhibit some level of site fidelity within ponds and that the distribution of differently sized animals within a pond may play a role in determining an individual’s realized niche. Within-pond site fidelity does not appear to differ between males and females. Juveniles exhibit the lowest level of site fidelity, although this could be an artifact of juveniles being more easily scared from the thermoregulation zones by observers. Additional field seasons are needed to determine if within-pond site fidelity persists across active seasons and if individuals adjust their niche as size structure dynamics change over time.
