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Continuous expanses of relatively undisturbed southwestern desert are becoming increasingly limited. Desert lands are intersected by networks of roadways and utility corridors and are being converted to agricultural and urban uses. With the construction of the Hayden-Rhodes Aqueduct, there is evidence that many areas of the natural Sonoran Desert ecosystem have experienced physical alteration and/or destruction.
I examined vegetation on the upslope and downslope sides of the Hayden-Rhodes Aqueduct to determine the extent of flow alterations on vegetation communities. Three regions were sampled using Daubenmire plots and pace transects to determine mean percent vegetation cover. Means for individual plant species were compared using Analysis of Variance among the three regions.
Statistical analyses revealed that more shrub and tree cover occurred on the upslope side of the aqueduct than on the downslope side. In addition, vegetation cover decreased downslope and vegetation cover upslope increased when data by individual regions were compared from pre- to post-construction conditions.
Recommendations have demonstrated the necessity for increased awareness of the potential landscape as well as wildlife impacts created by human-made barriers. If measures are not taken today in the selection and routing of human-made barriers, landscapes maybe altered and plant and animal species disrupted or even lost. The transferability of this information will better prepare planners, designers, scientists, and engineers in the planning, routing, and mitigation of future human-made barriers.