Structure and Dynamics of Spotted Salamander ( Ambystoma maculatum) Populations in Missouri.

Comparisons of spatial and temporal variation in demographic rates are crucial to understanding population dynamics. Yet, even well-studied species are often lacking in comparisons of such variability in demographic data, making these contrasts imperative to conduct in population ecology research. We conducted a long-term monitoring study of Spotted Salamanders ( Ambystoma maculatum) at five ponds in Missouri, USA. We sampled populations using drift fences, and monitored breeding immigration dates, adult population sizes, sex ratio, juvenile recruitment, metamorph sizes, and metamorph emigration dates. Generally, we found that our study populations exhibited characteristics similar to other populations across their distribution. We also found spatial and temporal variation among populations in nearly all demographic parameters, however, indicating that multipopulation and multiyear studies will likely improve our inferential abilities in understanding population dynamics. We observed an overall positive relationship between metamorph size and date of metamorphosis, but this pattern was not consistent across ponds or years, indicating that different environmental pressures might influence selection on these traits. Finally, we identified rainfall amounts and frequency as the primary factors that influenced adult and metamorph movement patterns to and from ponds. Overall, the spatial and temporal variation in demographic data we provided can be useful for population modeling or conservation planning, in addition to furthering our understanding of population ecology of Spotted Salamanders. [ABSTRACT FROM AUTHOR]