Long‐term trajectories of component change in the northern Great Basin

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This study reports an automated method of mapping rangeland fractional component cover over a large portion of the northern Great Basin, from 1986 to 2016 using a dense Landsat imagery time series. Over the 30‐yr period, shrub cover declined and bare ground increased. While few pixels had >10% cover change, a large majority had at least some change. All fractional components had significant spatial relationships with water year precipitation (WYPRCP), maximum temperature (WYTMAX), and minimum temperature (WYTMIN) in all years. Shrub and sagebrush cover in particular respond positively to warming WYTMIN, resulting from the largest increases in WYTMIN being in the coolest and wettest areas, and respond negatively to warming WYTMAX because the largest increases in WYTMAX are in the warmest and driest areas. The trade‐off of lowering temporal density against removing cloud‐contaminated years is justified as temporal density appears to have only a modest impact on trends and climate relationships until n ≤ 6, but multi‐year gaps are proportionally more influential. Gradual change analysis is likely to be less sensitive to n than abrupt change. These data can be used to answer critical questions regarding the influence of climate change and the suitability of management practices.