Discussion
Comparison of the carbon utilization and activity
profiles of the soil community from campsites and
adjacent intact sites provides a measurable and useful
analysis of community differences. Principal components analysis revealed a distinction between disturbed
and undisturbed sites in the upper layer of soil, but not
the lower layer. Differences in AWCD reflect a loss of
microbial activity in the upper layer of campsite soils, as
is indicated by the decrease in the number of substrates
used by different communities. The relatively long
incubation period of soil samples in Biolog plates
(192 h) should have allowed for the growth of even very
small microbial populations. The loss of ability to utilize
substrates despite the long incubation time represents a
significant decline in functional diversity of microbial
communities from campsite soils. While the number of
CFU did not vary on and off disturbed sites, the decline in percent actinomycetes suggests that there are structural changes in microbial communities. The data from
the spread plate and Biology plate analyses combined
suggest structural and functional shifts in microbial
communities in response to recreational impacts