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<br />002732 <br /> <br />Opportunities for Ecological Improvement Along the Lower Colorado River <br />Mark Briggs and Steve Cornelius <br />7/24/97 <br /> <br />Base recovery strategies on a thorough evaluation of site ecological conditions <br />Generally, successful recovery efforts are based on a sound understanding of the site's <br />current ecological condition. Depth to saturated soils, soil salinity concentrations, <br />presence of exotic plants, and intensity of use by recreationists and livestock are just <br />some of the factors that need to be evaluated to develop a sound site recovery plan <br />(Briggs 1996). Such information is also critical for developing realistic project <br />objectives. <br /> <br />Use plant materials that are adapted to curren.t site ecologic conditions <br />Revegetation planners often attempt to re-establish plants that were present prior to <br />disturbance even though they may no longer be adapted to the site's current hydrologic <br />condition. Depth to the saturated soils in some areas along the lower Colorado River <br />has increased significantly, making it difficult to establish many obligate riparian <br />species as cottonwoods and willows. This has often led to low establishment rates of <br />planted vegetation. <br /> <br />The Farmer's Market Bridge (site <br />#5) revegetation site, underscores <br />this point nicely. As the depth to <br />saturated soils at this site are <br />significant, all of the cottonwoods <br />and willows that were planted <br />either died or suffer from water <br />stress, while the majority of the <br />mesquite that were planted have <br />survived and appear healthy <br />(Fig. 4). In similar situations in <br />the future, using species such as <br />mesquite, quail bush, or saltbush <br />that are native to the region yet <br />are better able to survive in the <br />changed hydrologic environment <br />(or more saline conditions) will <br />probably significantly increase <br />the effectiveness of the <br />revegetation effort <br /> <br />Take advantage of agricultural <br />return flaws or runoff <br />Results experienced at Dredge <br />Spoil Site (Site #4) and No Name <br />Lake (Site #2) demonstrate the <br />validity of planting vegetation in <br /> <br />Figure 4. Farmer's Market Bridge revegetation site <br />with 11 year old cottonwoods. <br /> <br />Page 20 <br />