I conducted a comparative analysis of life-history attributes of two populations of painted turtles (Chrysemys picta) in the inland Pacific Northwest. A population inhabiting three wastewater lagoons contained proportionately more juveniles than one inhabiting a lake on a wildlife refuge. Average fecundity was significantly higher in the wastewater lagoon population (15.8 vs 13.4 eggs/clutch). Minimum size at the onset of sexual maturity was similar in the two populations for males and females (approximately 90 mm and 160 mm plastron length, respectively). However, turtles grew more rapidly and reached these sizes at younger ages in the wastewater lagoons (two years in males and 6-7 years in females) than in the lake population (three years in males and probably 8-10 years in females). These results contrast with local variation in the timing of maturity described for Trachemys scripta, for which females in populations of fast-growing turtles matured at the same age but at a larger body size with a concomitant increase in clutch size. The difference may be related to a contrast in the two species' clutch size-body size correlation, which is greater for T. scripta than C. picta. Interpopulational differences in fecundity and growth rate may have been related to caloric content and consistent seasonal availability of chironomid larvae and pupae fed upon heavily by the turtles in the waste-water lagoons. Lake turtles fed heavily upon odonate larvae in the early and middle active season, and on amphipods throughout the year. Comparison of the two study populations corroborates earlier reports of enhanced life-history parameters for C. picta in habitats that are nutrient enhanced by anthropogenic activity. Both study populations fit intraspecific patterns of increased clutch size and body size and later maturity for C. picta at more northern latitudes and higher elevations. The highly carnivorous diet of both populations, atypical for this species, may result in the relatively large body sizes and clutch sizes observed.
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