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Local Geographic Variation in Demographic Parameters and Body Size of Desmognathus fuscus (Amphibia: Plethodontidae)
Rudolph Theodore Danstedt, Jr.
Vol. 56, No. 5 (Late Summer, 1975), pp. 1054-1067
Published by: Wiley
Stable URL: http://www.jstor.org/stable/1936146
Page Count: 14
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Six Maryland populations of the dusky salamander Desmognathus fuscus were analyzed for differences in several life history and related parameters: timing of reproductive season, age at sexual maturity, reproductive rate, sex ratio, age structure, survival rate, and body size. Life history features are essentially similar in the populations. Adult @V @V lay eggs every year. Oviposition takes place during summer (June to early August). Larvae transform in late spring and early summer at about 9-12 mo of age. Males mature at 2 yr of age, @V @V at 3 yr. Survival rates (determined from age structures and sex ratios) differ considerably among the populations. Between-population differences in survival are greater for @M @M and older animals than @V @V and juveniles, respectively. Percentages of tail regeneration are in accord with these observations. Reproductive rate is greater in populations where adult survival is lower, Part, but not all, of these fecundity differences can be accounted for by positive size-fecundity relationships. Considerable interlocality variation in body size of transformed animals is evident. Body size and adult survival are negatively correlated, but no significant relationship between body size and juvenile survival exists. Populations in the same physiographic province are the most similar overall, but no general geographic trends are evident. Biotic interactions may account for some of the observed interpopulation variation, but evidence is unavailable to demonstrate any evolutionary significance to this variation. This study suggests that a complete understanding of the magnitude and nature of broad geographic demographic trends in organisms may necessitate a consideration of local variation.
Ecology © 1975 Wiley