Climate Change and North American Rangelands: Trends, Projections, and Implications

• Published in: Rangeland ecology & management 2013-09, Vol.66 (5), p.493-511
• Main Authors: Polley, H. Wayne, Briske, David D., Morgan, Jack A., Wolter, Klaus, Bailey, Derek W., Brown, Joel R.
• Format: Article
• Language: English
• Subjects: air temperature; atmospheric CO2; atmospheric precipitation; atmospheric warming; biogeography; biosphere; botanical composition; carbon dioxide; carbon dioxide enrichment; climate; Climate change; Climate models; climate variability; Drought; drying; Earth; ecoregions; ecosystem services; ecosystems; environmental conditions; environmental factors; fire regime; Global climate models; Global environmental change; Global warming; Grasses; Greenhouse effect; greenhouse gases; heat; industrialization; Infrared radiation; invasive species; Invited Synthesis; livestock; livestock production; metabolism; plant available water; plant growth; Plants; Precipitation; precipitation patterns; primary productivity; production technology; Rangeland ecology; rangelands; snowmelt; snowpack; Storm damage; summer; Trends; water use efficiency
• ISSN: 1550-7424; 1551-5028; 1551-5028
• DOI: 10.2111/REM-D-12-00068.1

The amplified “greenhouse effect” associated with increasing concentrations of greenhouse gases has increased atmospheric temperature by 1°C since industrialization (around 1750), and it is anticipated to cause an additional 2°C increase by mid-century. Increased biospheric warming is also projected to modify the amount and distribution of annual precipitation and increase the occurrence of both drought and heat waves. The ecological consequences of climate change will vary substantially among ecoregions because of regional differences in antecedent environmental conditions; the rate and magnitude of change in the primary climate change drivers, including elevated carbon dioxide (CO2), warming and precipitation modification; and nonadditive effects among climate drivers. Elevated atmospheric CO2 will directly stimulate plant growth and reduce negative effects of drying in a warmer climate by increasing plant water use efficiency; however, the CO2 effect is mediated by environmental conditions, especially soil water availability. Warming and drying are anticipated to reduce soil water availability, net primary productivity, and other ecosystem processes in the southern Great Plains, the Southwest, and northern Mexico, but warmer and generally wetter conditions will likely enhance these processes in the northern Plains and southern Canada. The Northwest will warm considerably, but annual precipitation is projected to change little despite a large decrease in summer precipitation. Reduced winter snowpack and earlier snowmelt will affect hydrology and riparian systems in the Northwest. Specific consequences of climate change will be numerous and varied and include modifications to forage quantity and quality and livestock production systems, soil C content, fire regimes, livestock metabolism, and plant community composition and species distributions, including range contraction and expansion of invasive species. Recent trends and model projections indicate continued directional change and increasing variability in climate that will substantially affect the provision of ecosystem services on North American rangelands.