Trends, p-values, and comparisons of select climate variables for the first 5 yrs (1986-1990) and last 5 yrs (2019-2023) of record for focal sagebrush (Artemisia sp.) associations in three US EPA level III ecoregions (Central Basin and Range, Norther

The sagebrush associations were derived from Chambers et al. (2023, 2024). Precipitation and temperature values were extracted for each sagebrush association from Daymet climate data (Thornton et al., 2022; https://daymet.ornl.gov). The PET values were calculated at monthly time steps using the Droogers and Allen modification of Hargreave’s equation (Hargreaves, 1994; Droogers and Allen, 2002), and mTMI values were calculated by subtracting the monthly total precipitation from the monthly PET. The climate data were resampled from 1 km2 to the mean value within a 2-hectare hexagonal cell. Trend was the mean marginal trend in each climate variable from 1986-2023 and the p-value was the significance of that slope from GLMMs calculated as 5-year running means and sums. Descriptive means and standard deviations were annual averages (temperature), sums (precipitation and mTMI), coefficient of variation (PPT and PET), or standard deviation (mTMI). PET CV described the CV of annual total precipitation for the previous 5 yrs. Differences between the first and last 5 years of the period of record were described by delta (last 5 yrs minus first 5 yrs). Data are based on subsampled data, approximately 500, 20 ha hexcells for each ecoregion-sagebrush combination with more than 20 km2. Descriptions of the climate variables are in the attached file "Climate_Variables_Used.xlsx".