RESULTS:

Macroinvertebrate sampling and analyses was conducted at sites on the Fryingpan River
in the fall of 2004 and spring 2005. In general, results of fall 2004 were similar to results
from previous years; however, some slight differences were observed (Table 1). Diversity
and evenness values indicated that conditions were similar to the fall of 2003. There was
higher density at FPR-RES (Figure 1), but higher biomass at FPR-TC and FPR-BAS
(Figure 2). The reason for the inconsistency between these metrics was due to changes in
the abundance of specific taxa in each community. The number of small invertebrates at
FPR-RES increased during the fall of 2004, while the density of some of the larger
macroinvertebrates declined. This resulted in a slight increase in densities and a slight
decrease in biomass at FPR-RES in the fall of 2003. The opposite effect of this process
occurred at site FPR-TC. A slight variation in community structure was also reflected in the
function analysis (Figure 3). Functional groups exhibited similar composition during all fall
sampling events at all sites, with slight variation occurring mostly in the scraper and
collector-filterer groups at FPR-TC.

The differences in metrics observed during three years of fall sampling may be well within
the range of natural variation that occurs at these sites. Changes in metric values would not
be considered substantial, or suggest that a major community altering event had recently
occurred (Table 1). It is important to note the yearly similarities among fall samples
because it suggests that changes in macroinvertebrate communities in spring samples are the
result of events that occur during winter months.