PARENT SESSION
Poster Session #8: Conservation Planning and Monitoring.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Design and implementation of riparian vegetation monitoring along the Colorado River in Grand Canyon.

Kearsley, Michael^*,1, Urquhart, N. Scott², ¹ Department of Biological Sciences, Flagstaff, AZ² Colorado State University, Fort Collins, CO

ABSTRACT- In designing a vegetation monitoring plan for large and complex riparian systems, three elements are critical: probabilistic sampling, regional representation, and integration with the hydrograph. Here we present a model monitoring program created for the Colorado River corridor of Grand Canyon National Park. The overall design was based on a previously constructed 2-dimensional flow model which divides the 385 km between Glen Canyon Dam and Diamond Creek into 703 segments defined by flow-controlling constrictions in the river channel. Segments were randomly selected in a spatially restricted manner after site tessellation to produce an augmented, rotating panel design. Sixty segments were to be sampled per year; 20 sampled every year and panels of 40 new sites rotated annually. Adjustments to sampling order were made after unavailable sites (cliffs, culturally and administratively sensitive areas) were determined. Within each segment, the flow model was used to predict river surface elevations for five stages spanning 1550 m³s^-1. These elevations were sampled at a randomly selected point in each of the 60 first year segments in 2001. The data showed expected relationships of plot wetland indicator status and total plant abundance with elevation, but no patterns of change in richness or diversity with disturbance history. Measurements taken at the time of vegetation sampling indicated that the stage-elevation estimates were within 50 m³s^-1 of their predicted values.

KEY WORDS: river regulation, vegetation monitoring, sampling design