Graduation Date
Fall 2024
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources: option Environmental Science and Management
Committee Chair Name
Kerry Byrne
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Erik Jules
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Lucy Kerhoulas
Third Committee Member Affiliation
HSU Faculty or Staff
Keywords
Sagebrush steppe, Sagebrush, Oregon, Drought, Seed bank, Climate change, Artemisia arbuscula, Artemisia cana, Invasive grass, Ventenata dubia, Aboveground net primary production, Belowground net primary production
Subject Categories
Environmental Science and Management
Abstract
Droughts are projected to increase in frequency and intensity due to climate change, which will significantly impact terrestrial ecosystems. However, the response magnitude will vary depending on a system's resistance and resilience to drought. Furthermore, drought may elicit different responses within the hierarchical levels of plant communities (i.e., individual, community, or ecosystem responses). These effects can extend beyond the drought's duration as legacies persist and influence previously disturbed systems. I assessed whether hierarchical responses occurred within two different adjacent sagebrush plant communities, dominated by Artemisia arbuscula and Artemisia cana, during and after an experimental drought. I used nondestructive point frame sampling to estimate aboveground net primary production (ANPP), root ingrowth cores to estimate belowground net primary production (BNPP), a greenhouse emergence study to monitor shifts in seed banks species composition during drought and recovery, while monitoring shifts in aboveground species composition.
The A. arbuscula community remained stable, with no changes in ANPP and BNPP, nor seed bank and aboveground species composition. However, ANPP and BNPP increased in previously droughted plots during the first recovery year within the A. cana community and Ventenata dubia cover, an exotic annual grass, increased throughout recovery. Interestingly, both sites experienced reductions in seed density across all plots during the first recovery year. While the A. arbuscula community is more resistant to drought, the A. cana community is at risk of biological invasion as post-drought conditions favor invasive annual grasses. These findings suggest that proactive preventative management against biological invasion should focus on mesic sagebrush communities.
Citation Style
APA
Recommended Citation
Chavez, Francisco Jesus, "Drought's lingering shadow: Monitoring the recovery of sagebrush steppe plant communities after four years of experimental drought" (2024). Cal Poly Humboldt theses and projects. 815.
https://digitalcommons.humboldt.edu/etd/815