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<br />but also elevated alluvium salinity. Boron, to which naturalized Tamarix ramosissima
<br />is tolerant, was also elevated in soils following fire. Lower moisture in the upper
<br />30 cm of burned site soil profiles was attributed to shifts in evapotranspiration
<br />following fire. Higher leaf stomatal conductance occurred in all taxa on burned sites.
<br />This is apparently due to higher photosynthetic photon flux density at the midcanopy
<br />level and may be partially mitigated by reduced unit growth in resprouting burned
<br />individuals. Predawn water potentials varied little among sites, as was expected for
<br />plants exhibiting largely phreatophytic water uptake. Midday water potentials in
<br />recovering Salix gooddingii growing in the Colorado River floodplain reached levels
<br />which are considered stressful. Decreased hydraulic efficiency was also indicated for
<br />this species by examining transpiration-water potential regressions. Recovering,
<br />burned Tamarix and Tessaria sericea had enriched leaf tissue .delta.13C relative to
<br />unburned controls. Higher water use efficiency following fire in these taxa may be
<br />attributed to halophytic adaptations and to elevated foliar nitrogen in Tessaria.
<br />Consequently, mechanisms are proposed which would facilitate increased community
<br />dominance of Tamarix and Tessaria in association with fire. The theory that whole
<br />ecosystem processes are altered by invading species may thus be extended to include
<br />those processes related to disturbance.
<br />
<br />172. Busterud, J .A, 1974, The future of regional planning in the United States, in Crawford, AB., and
<br />Peterson, D.F., eds., Environmental management in the Colorado River Basin: Logan, Utah,
<br />Utah State University Press, p. 67-74.
<br />
<br />173. Butcher, W.S., 1978, Salinity management and the development of the Colorado River Basin; a
<br />multidisciplinary problem with international implication (1976): Trenton, N.J., Proc. Univ.
<br />semin. Pollut. Water. Resour., v. 9, p. B1-BI8.
<br />
<br />174. Butcher, W.S., 1979, Salinity management and water resources development: GeoJoumal, v. 3,
<br />no. 5, p. 457-460.
<br />
<br />The interrelationship of salinity management and water management is a factor which
<br />is sometimes easily overlooked in the water resources planning, even though it can
<br />place a limit on the degree of water resource development within a basin. Costs and
<br />control measures of salinity management are considered on a case study of the
<br />Colorado River Basin where salinity damages are found to be higher than previously
<br />estimated. After review of the costs of salinity management, the possible control
<br />measures, and research on adaptions in agricultural use of more saline water, it can
<br />be concluded that, at the very least, the management of water quantity and water
<br />quality, especially in arid regions, are closely intertwined.
<br />
<br />175. Butler, D.L., 1985, Discharge and water quality of springs in Roan and Parachute Creek Basins,
<br />northwestem Colorado, 1981-83: U.S. Geological Survey Water-Resources Investigations
<br />Report 85-4078,145 p.
<br />
<br />176. Butler, D.L., 1986, Sediment discharge in the Colorado River near De Beque, Colorado:
<br />U.S. Geological Survey Water-Resources Investigations Report 85-4266,30 p.
<br />
<br />177. Butler, D.L., 1987, Sediment discharge in Rock Creek and the effect of sedimentation rate on the
<br />proposed Rock Creek Reservoir, northwestern Colorado: U.S. Geological Survey Water-
<br />Resources Investigations Report 87-4026, 23 p.
<br />
<br />BIBLIOGRAPHY 33
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