Long-Term Vegetation Change on the Colorado Plateau

Science Center Objects

The Colorado Plateau, centered around the four corners area of the Southwest, and includes much of Arizona, Utah, Colorado, and New Mexico, is a large and important component of U.S. drylands. This important home to mountains, desert basins, dramatic canyons, and arid woodlands and grasslands is also one of North America’s most rapidly warming hot spots, with rates of warming of up to 2-3° C within the last 100 years. Such warming trends have already been credited with increasing drought frequency and severity, resulting in the potential loss of vegetation and soil, which can have direct impact to wildlife and people. Therefore, understanding how ecosystems of the Colorado Plateau will respond to ongoing regional warming is important for predicting the trajectory of change and aid with land management decisions.

Project

This project explores how dryland vegetation and soils will respond to past, current, and future climate and land use changes on the Colorado Plateau. Using data collected by the USGS starting in 1996, we are exploring trends and potential trajectories of dryland landscapes across a historic grazing gradient in Canyonlands National Park. Collected data include vegetation cover surveys, soil measurements (e.g. nutrient and carbon content, soil texture and mapping), and landscape characterizations. Recent analysis of long-term data shows ecosystem sensitivities to ongoing regional warming, with observed declines in biological soil crusts largely attributed to warmer summertime temperatures. Vegetation communities demonstrate more variability, with highest plant cover occurring in years with more precipitation. Findings from this study will inform Department of Interior and other federal, state, tribal and private land management decisions aimed at mitigating effects of climate change. Additionally, by providing information that will help distinguish ecosystem change due to climate alone from those changes attributable to land use (i.e. livestock grazing), the results of this work will help managers of complex, multi-use landscapes identify successful management actions.

Part of Canyonlands National Park - aerial view

Aerial view of study area in Canyonlands National Park. (Credit: Jayne Belnap, U.S. Geological Survey. Public domain.)

Repeat photography of biological soil crust over 15 years

Series of repeat photographs of biocrusts taken from the same area in 2004, 2009, 2014, and 2019. Letters on photographs indicate the same spot across the time series.

(Credit: Rebecca Finger-Higgins, Southwest Biological Science Center. Public domain.)