Path estimates, p-values, and standardized path estimates for groupwise structural equation models (SEMs) by burn history (not burned and burned after 1999) for focal sagebrush (Artemisia sp.) associations in three US EPA level III ecoregions (Centra

The sagebrush associations were derived from Chambers et al. (2023, 2024). The area and frequency of wildfires with extents larger than 405 ha were derived for each sagebrush association using the Monitoring Trends in Burn Severity (MTBS, 2024) burned area boundaries dataset for 1986–2023. Plant functional type and bare ground data were derived from the Rangeland Analysis Platform (RAP; Allred et al. 2021) at 30 m2 and averaged over a 2-hectare hexagonal cell (hexcell). 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. Descriptions of the climate variables are in "Climate_Variables_Used.xlsx". Piecewise structural equation models (piecewiseSEM; Lefcheck, 2016) were used to evaluate the causal effects of the climate variables and shrub, tree, and bare ground cover (predictor variables) on PFG cover and AFG cover (response variables), as well as PFG cover (predictor) on AFG cover (response), for select sagebrush associations in both not burned and burned areas. The path estimates, p-values, and standardized path estimates were calculated or each set of predictor and response variables using groupwise SEMs. Constrained indicated that there was no significant difference in path estimates within ecoregions. The black sagebrush SEM was limited to Central Basin and Range ecoregion, the low sagebrush SEM was limited to the Northern Basin and Range, and the WY/Basin big sagebrush SEM was limited to the Central Basin and Range and Northern Basin and Range ecoregions. The Wyoming sagebrush and mountain big sagebrush SEMs were constructed for all three ecoregions. AFG = annual forb and grass; PFG = perennial forb and grass.