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9160 Water level and quality data can be collected to gain infor- mationon the variables determining vegetative growth, composition, and presence, Five- to 10-foot-deep observa, tion wells, consisting of 2-incli,diameter PVC pipe with 0.01 inch slots should be installed to a depth of 5 or 10 feet, depending on the depth of the root zone, at various locatiouswithin each vegetation type, The data on ground, water elevation and salinity collected from these wells can be analyzed to describe existing vegetation-hydrologic relationships, and detect or predict changes resulting from salinity control development. + \l Manipulative tests of vegetation response may be ap- propriate when changes in streamflow or water quality resulting from salinity control measures are expected, but the effects on vegetation are unknown or uncertain, Manipulative tests of vegetation response to changes in ground-water or surface,water supply can be conducted prior to project implementation, Test sites can be estab- lished where different plots would be supplied with irriga- tion water from various local supplies of different quality, Native or desirable species are grown and their response in terms of growth and survival monitored, Species selec- tion should be based on what grows in the area, and what can be grown to enhance the environment for wildlife usage. These tests of vegetation establishment demon- strate which plants are most successfully grown in conjunc' tion with salinity control projects to maintain or enhance wildlife habitat values. longer wave-length reflects differently from vigorous and stressed vegetation, both of which may appear uniformly green in normaI,color photographs, Evaluations of plant vigor can be made from false-color infrared photos where water or salt stress is suspected. '~ Vegetative types should be quantified to provide a statisti- cal means for correlation with other environme,ntal vari, abies. Variables typically derived from the vegetation data are cover, density, and productivity, An index value calcu- lated fro/ll a combination of these variables may also be used, Methods of vegetation data and analysis are covered in V.S. Fish and Wildlife Service (1981) and Mueller-- Dombois and Ellenberg (1974), The Habitat Evaluation Procedure (HEP) developed by V.S, Fish and Wildlife Service (1980) may also be used in impact assessment and project planning, This method may be used in comparisons of: Onfarm Wildlife Habitat Onfarm wetland and other wildlife habitat should be monitored to establish base information and determine changes in quality and quantity caused by implementation and operation of the salinity control projects. Because changes can be cumulative over, a number of years, a 'Iong- term program is needed, Some of the required data such as land use, ground,water level, and soil salinity are com- monly collected for use by other disciplines, Monitoring of wetlands could be correlated with monitoring of irriga- tion and economics. 2. Relative values of the same area under different future conditions. \ I Habitat types should be mapped on a sample of agricul- ture units prior to installation of salinity control practices to determine present habitat quality. The area of each habitat type should be computed for each unit sampled and summarized, Agricultural units should be remapped and areas of habitat recomputed at 3 to 5 year intervals fol- lowing installation of practices, Total habitat change due to the onfarm salinity control program then can be deter" mined. This is done by extrapolating the ratio of habitat change on the sample agricultural units to the total area treated. 1. Relative value of different areas at the same time, or The latter comparison would provide a means of evaluat- ing impacts of salinity control projects on specific areas, 18 19