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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #417674
Research Project: Knowledge Systems and Tools to Increase the Resilience and Sustainability of Western Rangeland Agriculture

Location: Range Management Research

Title: Diverging trends of vegetation communities across ecoregions of the western United States

Author
item DHITAL, SAROJ - New Mexico State University
item Webb, Nicholas
item McCord, Sarah
item BRADFORD, JOHN - Us Geological Survey (USGS)
item SCHLAEPFER, DANIEL - Northern Arizona University
item TREMINIO, RONALD - New Mexico State University
item DUNIWAY, MICHAEL - Us Geological Survey (USGS)
item NAUMAN, TRAVIS - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2024
Publication Date: 12/13/2024
Citation: Dhital, S., Webb, N.P., McCord, S.E., Bradford, J.B., Schlaepfer, D.R., Treminio, R.S., Duniway, M.C., Nauman, T.W. 2024. Diverging trends of vegetation communities across ecoregions of the western United States. American Geophysical Union. Abstract.

Interpretive Summary:

Technical Abstract: There is growing concern about the resilience of vegetation in western US dryland ecosystems as the region faces compounding disturbances from climate change, regional megadrought, wildfires, spread of invasive plants, land use practices, and infrastructure development. In many areas across the western US, vegetation communities have already undergone extensive change. Climate simulations have projected more stress on dryland ecosystems and a decline in production in the coming decades due to uncertain summer monsoons and more intense and frequent droughts. Monitoring vegetation communities is essential to assess how dryland vegetation has been responding to recent climate change. We used 20 years (2001-2020) of plant functional group cover data from the Rangeland Analysis Platform to identify trends of vegetation communities and establish their relationships to climate variables across the western US. We identified increasing trends of annual forbs and grasses and perennial forbs and grasses in the Great Basin but decreasing trends of perennial forbs and grasses across the northern Chihuahuan Desert during the 2001 to 2020 period. These trends were associated with increasing precipitation and reduced vapor pressure deficit (VPD) in the northern Great Basin and substantially increased VPD across the northern Chihuahuan Desert. Increasing woody cover and decreasing bare ground trends occurred across most dryland ecoregions, including the Colorado Plateau and the Mojave Desert. Diverging trends of annuals and perennials occurred in the Great Basin, Chihuahuan Desert, and the Colorado Plateau between 2001-2010 and 2011-2020. No trends to increasing trends of annuals and perennials, from 2001s decade to 2011s decade, in the Great Basin and increasing to decreasing trends of perennials in the Chihuahuan Desert, and Colorado Plateau were prominent. Annual forb and grass cover and woody cover have stronger lagged relationships with the antecedent cooler season Pacific Decadal Oscillation relative to the El Nino-Southern Oscillation in the Great Basin and the Chihuahuan Desert, respectively. These results provide insights into how vegetation communities have been changing over the last two decades, which can help inform adaptive land management strategies for the sustainable use of dryland ecosystems.