Age, Growth, and Long-Term Site Fidelity in the Terrestrial Plethodontid Salamander Plethodon kentucki
Based on mark-recapture data collected over seven years on the salamander Plethodon kentucki, I examined (1) longevity and long-term site fidelity, (2) growth curves for each sex derived from both cross-sectional and longitudinal data on body size, (3) whether growth curves generated from the two kinds of data were comparable, and (4) how the relationship between adult body size and age in this species compares to that in other plethodontid salamanders. Recapture rates indicate that about 86% of males and 82% of females survived and remained in the study area from one year to the next. Most individuals recaptured at the end of the study period were within, or less than 2 m from, the home range they occupied at the beginning. Maximum age estimates were 13 yr for males and 16 yr for females. Growth curves derived from cross-sectional and longitudinal data were very similar. For both sexes, there is rapid growth up to the time of first reproduction (about 4 and 5 yr for males and females, respectively) and continued growth for 2 to 4 yr afterward but relatively little growth after 9 yr of age. Males may have a greater rate of growth prior to sexual maturity, but females grow for a longer period and attain a greater body size. There is much variance in adult body size within a given age class for both sexes. The correlation between body size and age was slightly greater in males than in females, and the correlation was significant for the combined data. Similarly, the size-age correlation in other plethodontid species is stronger for males than for females, which may be because of a greater variability in growth after sexual maturity in females than in males.Abstract
Relationship between estimated age and body size (SVL) of individual (A) male (n = 10) and (B) female (n = 8) Plethodon kentucki recaptured between 1992 and 1999
Gompertz growth curves for male and female Plethodon kentucki calculated from (A) cross-sectional and (B) longitudinal recapture data on body size. The integrated and differential forms of the growth equations are S = S ∞ exp[−exp − a(t + to)] and G = −a lnS + b, respectively (where S is body size, S ∞ is asymptotic body size, t is time, to is the constant of integration, and G is specific growth rate). Growth equations calculated from cross-sectional data were S = 59.07exp[−exp − 0.457(t − 1.205)] and G = −0.457 lnS + 1.86 for females, and S = 56.94exp[−exp − 0.592(t − 1.157)] and G = −0.592 lnS + 2.39 for males. Growth equations calculated from longitudinal data were S = 57.90exp[−exp − 0.574(t − 1.163)] and G = −0.574 lnS + 2.33 for females, and S = 55.26exp[−exp − 0.596(t − 1.155)] and G = −0.596 lnS + 2.39 for males