STRUCTURE AND DYNAMICS OF RINGED SALAMANDER (AMBYSTOMA ANNULATUM) POPULATIONS IN MISSOURI

We report a detailed account of the structure and dynamics of five populations of Ringed Salamanders (Ambystoma annulatum Cope, 1886) in Missouri, USA, studied over a 4-yr period. The average date of capture for breeding males varied from 30 August to 2 October, and average date of capture for breeding females varied from 9 September to 7 October. The sex ratio was consistently male biased and averaged 2.05 males to each female. The smallest breeding female was 77 mm snout-vent length ([SVL]; mean = 96.3 mm) and the smallest breeding male was 66 mm SVL (mean = 94.2 mm). Eggs and larvae were present in September and October each year, and the larval period varied from 7 to 9 mo. Juveniles metamorphosed in all years in every pond, albeit in low numbers (6-631). The mean SVL of metamorphosing juveniles among all years and ponds was 39.2 mm. Intra-annual body size of emerging juveniles declined over time; juveniles that metamorphosed early were larger in body size than those metamorphosing later in the summer. Production of juveniles per female averaged 0.76 (range, 0.056-2.929), and survival of juveniles from egg to metamorphosis averaged 0.2% (range, 0.01%-0.75%). Both females and males can reach reproductive maturity at 1 yr of age, but most return at 2-3 yr of age. Management of the Ringed Salamander must focus on all life-history stages; protecting the aquatic stage to maximize the number and fitness of metamorphosing juveniles, managing the terrestrial habitat to maximize survival to first reproduction, and monitoring connectivity to promote metapopulation dynamics.