Abstract
Movement and demographic rates are critical to the persistence of
populations in space and time. Despite their importance, estimates of
these processes are often derived from a limited number of populations
spanning broad habitat or environmental gradients. With increasing
appreciation of the role fine-scale environmental variation in
microgeographic adaptation, there is need and value to assessing
within-site variation in movement, growth, and demographic rates. In
this study, we analyze three years of spatial capture-recapture data
collected from a mixed-use deciduous forest site in central Ohio, USA.
Study plots were situated in mature forest on a slope and in
successional forest on a ridge but were separated by less than 100-m
distance. Our data showed that the density of salamanders was less on
ridges, which corresponded with greater distance between nearest
neighbors, less overlap in core use areas, greater space-use, and
greater shifts in activity centers when compared to salamander occupying
the slope habitat. However, these differences were moderate. In
contrast, we estimated growth rates of salamanders occupying the ridge
to be significantly greater than salamander on the slope. These
differences result in ridge salamanders reaching maturity more than one
year earlier than slope salamanders, increasing their lifetime fecundity
by as much as 43%. The patterns we observed in space use and growth are
likely the result of density-dependent processes, reflecting differences
in resource availability or quality. Our study highlights how
fine-scale, within-site, variation can shape population demographics. As
research into the demographic and population consequences of climate
change and habitat loss and alteration continue, future research should
take care to acknowledge the role that fine-scale variation may play,
especially for organisms with small home ranges or limited vagility.