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ephemeral streams, livestock grazing, NDVI, off-stream water, piosphere, riparian zones


Uneven and/or inefficient livestock distribution is often a product of an inadequate number and distribution of watering points.Placement of off-stream water practices (OSWP) in pastures is a key consideration in rangeland management plans and is criticalto achieving riparian recovery by improving grazing evenness, while improving livestock performance. Effective OSWPplacement also minimizes the impacts of livestock use radiating from OSWP, known as the ‘‘piosphere.’’ The objective of thisstudy was to provide land managers with recommendations for the optimum placement of OSWP. Specifically, we aimed toprovide minimum offset distances of OSWP to streams and assess the effective range of OSWP using Normalized DifferenceVegetation Index (NDVI) values, an indicator of live standing crop. NDVI values were determined from a time-series of SatellitePour l’Observation de la Terre (SPOT) 20-m images of western South Dakota mixed-grass prairie. The NDVI values inephemeral stream channels (in-channel) and uplands were extracted from pre- and post-OSWP images taken in 1989 and 2010,respectively. NDVI values were normalized to a reference imagine and subsequently by ecological site to produce nNDVI. Ourresults demonstrate a significant (P,0.05) increase in the nNDVI values of in-channel vegetation within 1 250 m of OSWPfollowing their implementation. The area of piospheres (n¼9) increased with pasture size (R2¼0.49,P¼0.05) and increasedwith average distance to OSWP in a pasture (R2¼0.43,P¼0.07). Piospheric reduction in nNDVI was observed within 200 m ofOSWP, occasionally overlapping in-channel areas. The findings of this study suggest placement of OSWP 200 to 1 250 m fromstreams to achieve optimal results. These results can be used to increase grazing efficiency by effectively placing OSWP andinsure that piospheres do not overlap ecologically important in-channel areas.

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Rangeland Ecology & Management





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Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. Outside the U.S.: © 2013 The Society for Range Management