Sagebrush vegetation response to experimental drought

These data are from the research project Drought and Sagebrush: Management
Implications, conducted by Kerry Byrne and Kristen Kaczynski from 2016 -
2020. The dataset contains research results related to species
composition, forb density, and above and belowground net primary
production in response to four years of experimental drought using rainout
shelters and control plots. We used rainfall shelters to create a
1-in-100-year drought at each site to understand how chronic (4 year)
drought will impact common, but understudied sagebrush steppe plant
communities. We conducted our study at two sites approximately 60 m apart
within a grazing exclosure established in 1993 in Klamath County, Oregon,
USA (42.301111, -121.018056). The two study sites have unique edaphic
features that lead to differences in the ecological structure and function
of the plant communities. One site (AA site) is dominated
by Artemisia arbuscula (low sagebrush) while the other site (AC
site) is dominated by A. cana (silver sagebrush). We found that above- and
belowground net primary production at both sites were remarkably resistant
to drought. Litter increased over time in drought plots at the more
productive AC site, and we hypothesize that hydraulic lift and litter
interacted to increase shallow soil water content under drought at that
site. The AA site, with harsher edaphic features and a soil duripan,
experienced fewer changes in plant community composition than the more
productive AC site, potentially due to the presence of specialized plant
species at the harsher site. Non-native plant cover increased (primarily
from Ventenata dubia, an invasive annual grass) and native forb
cover and density decreased over time. This suggests that management may
be needed to conserve native forb diversity and limit species invasion,
especially as climate and fire regimes change.