Ecological sites provide a conceptual division of the landscape and a consistent framework for
delineating and describing land. The Natural Resources Conservation Service develops these ecological
sites so they can used for land management decision-making, monitoring, assessment and policy.
Development of ecological site concepts have traditionally been based on correlations between soil
properties and vegetation, however these are not sufficient for ecological site concept development for
wet areas. Site concepts for wet areas need to involve a greater emphasis on hydrology and energy
along with considering several aspects that also influence site dynamics, including geomorphology,
climate, physiochemical environment, vegetation, and wildlife. These properties can be used to
delineate sites with similar potential. This new concept for delineating and classifying wet sites was
applied to riparian areas managed by the National Park Service in Utah. The following parameters were
collected to determine site classification: valley width, channel geometry, stream sinuosity, slope,
substrate, fluvial landforms, stream flow regime, ground water depth, and plant community
composition on landforms within the valley bottom.
Results/Conclusions
Valley width, flow regime, proximity to channel, and ground water depth had the most influence on
plant community dynamics. Valley widths in this regional are relatively narrow and the stream channel
sinuosity is constrained by valley width. Valley bottoms with similar widths were more like each other
than those with wider valleys. Vegetation varied based on distance from the stream channel and ground
water depth. Three dominant plant communities were found throughout the study area, graminoid,
shrub and tree dominated, moving away from the stream channel. Valleys with perennial flow versus
intermittent flow in streams also had differences in plant community organization and dynamics.
Detailed information on plant community dynamics within valley bottoms is critical to understand how
to restore ecological dynamics in riverine systems. The classification will also aid in clarifying riparian
ecological site concepts that can be applied to other stream systems in the Colorado Plateau.