Award Date

5-2004

Degree Type

Thesis

Degree Name

Bachelor of Science

Department

Environmental Science

Advisor 1

Dr. Patrick J. Drohan, Department of Environmental Studies, University of Nevada Las Vegas

Number of Pages

37

Abstract

The monitoring of Mojave Desert plant communities during and following disturbance is an important process that could provide invaluable information about disturbance/recovery regimes in similar arid environments across the globe. Blackbrush communities are of particular interest because of their low replacement rate, which makes them highly susceptible to disturbance. Roads in the Mojave Desert have been associated with soil compaction resulting in a lack of vegetation as well as an increase in invasive species cover in the immediate proximity. To investigate these statements, eight fifty-foot line transects were established in each of three plot types (perpendicular to dirt roads, perpendicular to single-track roads, and controls) in Red Rock Canyon, NV. Two questions were posed of this study: 1) Is percent invasive species cover greater on transects in proximity to roads or on transects situated in undisturbed areas? 2) Does distance from a road influence invasive species cover? SPSS for Windows was used to conduct cross-tabulation tests in order to establish points of statistical significance (p<0.05). Results reveal that both invasive and endemic species cover is greater in undisturbed plots. Furthermore, three cross-tabulation tests reveal that a statistical relationship indeed exists between endemic/invasive species and proximity to a road. Examination of the cross-tabulation output reveals that 37.6% of all invasive species encountered in road transects occurred within ten feet of the road. Future investigations of the ecological impacts of roads should include fully developed roads and also account for bare ground as a disturbance impact equal to that of invasive species.

Keywords

Ambrosia dumosa; Blackbrush communities; Burro-weed; Coleogyne ramosissima; Creosote; Invasive species; Larrea tridentata; Mojave desert; Off-road travel; Native plant communities; Red Rock Canyon National Conservation Area; Nevada; Roads; Soil compaction; White bursage; Vegetation disturbance

Disciplines

Desert Ecology | Environmental Sciences | Plant Sciences | Systems Biology | Weed Science

Language

English


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