Future dryland resistance and resilience

Objectives: This project provided new metrics of ecological resilience and resistance to invasive plants.  We integrated a proven ecosystem water balance model with widespread observational data about dryland plant community responses to disturbances to develop and deliver improved metrics of R&R.  Specifically, we addressed the following objectives: 

1. Develop R&R metrics from ecosystem water balance simulations. 

2. Assess current spatial patterns in the R&R indicators developed in objective 1. 

3. Quantify long-term trajectories of R&R indicators under future climate. 

Approach: For objective 1, we used the SOILWAT2 ecosystem water balance model to simulate patterns of ecological drought as indicators of ecological resilience to wildfire and resistance to invasive plants.  These results provided detailed water balance modeling from which we can identify the specific moisture and temperature metrics that explain R&R in drylands.  For objective 2, we expanded the water balance simulations estimate the distribution of new R&R indicators across the extent of the sagebrush region.  For objective 3, we utilized projections from global climate models as input to our water balance model, quantifying how changes in climate will alter both the indicators and R&R categories.  We explicitly quantified how variation among climate projections impacts uncertainty in future R&R changes.

Objective 2 – Assess current spatial patterns in the R&R indicators

We integrated our suites of climate and ecological drought indicators (objective 1) with field data about plant community composition and expert knowledge to generate a new predictive algorithm for estimating ecological resistance and resilience.  We then applied that new algorithm to estimate R&R in sagebrush and dry woodland ecoregions across the western U.S. and have published those results (Chambers et al. 2023.)  Figures below (from Chambers et al 2023): Left: proportion of total area in different resilience and resistance categories in each of the ecoregions. Portions of ecoregions that lie outside of the sagebrush biome are unclassified (“NA”). NBR = Northern Basin and Range; SRP = Snake River Plain; CBR = Central Basin and Range; CP = Colorado Plateau; WB = Wyoming Basin; MR = Middle Rockies; NWGP = Northwestern Great Plains. Right: maps of predicted (a) resilience and (b) resistance for the study area with Level III EPA ecoregions and states delineated (US EPA 2022). Areas that do not support the focal ecosystems are shown in light yellow (“NA”). 

Interactive web-app: projected R&R layers

Publications

• Chenoweth, D. A., D. R. Schlaepfer, J. C. Chambers, J. L. Brown, A. K. Urza, B. Hanberry, D. Board, M. Crist, and J. B. Bradford. 2023. Ecologically relevant moisture and temperature metrics for assessing dryland ecosystem dynamics. Ecohydrology:e2509. https://doi.org/10.1002/eco.2509 

• Chambers, J. C., J. L. Brown, J. B. Bradford, D. I. Board, S. B. Campbell, K. J. Clause, B. Hanberry, D. R. Schlaepfer, and A. K. Urza. 2023. New indicators of ecological resilience and invasion resistance to support prioritization and management in the sagebrush biome, United States. Frontiers in Ecology and Evolution 10

• Schlaepfer, D. R., J. C. Chambers, A. K. Urza, B. B. Hanberry, J. L. Brown, D. I. Board, S. B. Campbell, K. J. Clause, M. R. Crist, and J. B. Bradford. 2025. Declining ecological resilience and invasion resistance under climate change in the sagebrush region, United States. Ecological Applications 35:e3065. https://doi.org/10.1002/eap.3065

Data releases

• Schlaepfer, D. R., Andrews, C. M., & Bradford, J. B. (2022). Historical and future ecological drought conditions for rangelands of the western U.S. U.S. Geological Survey Data Release. https://doi.org/10.5066/P97S8RAC

• Schlaepfer, D.S. and Bradford, J.B.  In Preparation. Projected indicators of dryland resistance and resilience for rangelands in the Sagebrush Biome for the 21st century.  U.S. Geological Survey Data Release.

• Schlaepfer, D.S. and Bradford, J.B.  In Preparation. Ecologically relevant annual (1980-2021) moisture and temperature metrics for rangelands in the Sagebrush Biome.  U.S. Geological Survey Data Release.

Presentations

• Bradford, J.B. & Schlaepfer, D.S.  2020.  Climate change impacts on dryland resistance-resilience & sagebrush plant communities.  USGS Sagebrush and wildfire information transfer workshop.  December 9, 2020.  Online: 101 attendees.

• Bradford, J.B.  2021. Climate change impacts on soil moisture and implications for plant regeneration in drylands.  University of Arizona  Rangeland Resilience Seeding Workshop.  October 5, 2021.  Virtual.  ~30 attendees.

• Bradford, J.B. et al. 2022.New resilience and resistance metrics for assessing climate change impacts in drylands.  USDA Forest Service and JFSP planning meeting.  February 8, 2022.  Online.

• Bradford, J.B. et al. 2022. New metrics for quantifying ecological drought to inform resilience and resistant in drylands.  Society for Rangeland Management 2022 Annual Meeting.  Feb 9, 2022. Online.

• Bradford, J.B. 2022. Climate change, ecological drought & vegetation challenges in western drylands.  High Altitude Revegetation Conference.  April 13, 2022. Fort Collins, CO.  Keynote Address.

• Bradford, J.B., Crist, M. Chenoweth, D.A., Schlaepfer, D.R., Chambers, J.C., Urza, A., Hanberry, B, Brown, J., Board, D.I. 2022.  Ecological drought metrics to understand dryland ecosystem dynamics. Ecological Society of America Annual Meeting.  Montreal, Canada, August 2022.

• Bradford, J.B., D.A. Chenoweth, D.R. Schlaepfer, J.C. Chambers, J.L. Brown, J.L., A.K. Urza, B. Hanberry, D. Board, and M. Crist. 2022. Ecological drought metrics to understand dryland ecosystem dynamics. Biennial Conference of Science & Management for the Colorado Plateau & Southwest Region, Flagstaff, AZ.

• Schlaepfer, D.R., J.C. Chambers, J.L. Brown, D.I. Board, S.B. Campbell, K.J. Clause, B. Hanberry, A.K. Urza, M. Crist, and J.B. Bradford. 2022. Rethinking indicators of dryland resistance and resilience for the 21st century. Biennial Conference of Science & Management for the Colorado Plateau & Southwest Region, Flagstaff, AZ.

• Bradford et al.  2022.  Understanding climate change & ecological drought impacts on dryland vegetation & plant communities: how we use AIM data.  Nov 10, 2022.