Human Effects on Aquatic and Riparian Organisms in the Canyons of Canyonlands and Arches National Parks and Natural Bridges National Monument

Abstract

We made 1 trip to all three study sites to familiarize ourselves with the study areas and meet and discuss the project with the local Park Service personnel in charge of the project. While the canyon at Arches National Park was as we expected it to be, the canyons in Canyonlands and at Natural Bridges were quite different from other canyons in which we have worked. These later canyons were deeper, had steeper canyon walls, and had thicker vegetation than prior canyons in which we have worked. The tall canyon walls shade the canyon bottom creating great differences in temperature/light/moisture levels over very short distances. The vegetation can change radically just by going around one bend in the canyon bottom. The heterogeneous nature of the habitats in these deep canyons require us to subsample to a much greater degree than we proposed in the original proposal. The local Park Service staff had already anticipated this problem and had suggested in their review of our proposal that we subsample to a greater degree. We have taken our original sampling scheme and broken it into a series of smaller subsamples to solve the problem of heterogeneous habitat types in each treatment type (i.e., area with road, area with trail, etc.).