Vegetation cover from a precipitation manipulation experiment at the Spruce Gulch Wildlife and Research Preserve, Colorado

These data consist of plot-level plant species cover measurements from a precipitation manipulation experiment located in the Spruce Gulch Wildlife and Research Reserve near Boulder, Colorado. This data release consists of absolute percent live foliar cover measurements of all plant species within each plot for the years 2011, 2012, 2013, 2020, 2021, 2022, and 2023. From 2011-2013, plots received one of three precipitation manipulations over the winter (October through March) and summer (April-September): 'reduce' = 50 percent reduction in ambient precipitation, 'increase' = 50 percent increase in ambient precipitation, or 'ambient' = no manipulation of precipitation. Precipitation was reduced through the use of rain-out shelters that blocked precipitation from half of each plot. Precipitation was increased by irrigating plots using water from a local well. The 'increase' precipitation treatments were discontinued after 2013, and thus some winter and summer precipitation treatments for plots were reassigned in 2020-2023.