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Drought Vulnerability Assessment to Inform Grazing Practices on Rangelands

Increased climate variability, including more frequent and intense drought, is projected for the  southwestern region of the United States. Increased temperatures and reduced precipitation lower soil water availability resulting in decreased plant productivity and altering species composition which may affect forage quality and quantity. Reduced forage quality and increased heat stress attributable to warmer temperatures could lead to decreased livestock performance in this system, which is extensively used for livestock grazing. Mitigating the effects of increasing drought is critical to social and ecological stability in the region. Reduced stocking rates, change in livestock breeds and/or grazing practices are general recommendations that could be implemented to cope with increased climatic stress. Ecological Sites (ESs) and their associated state and transition models (STMs) are tools to help land managers implement and evaluate responses to disturbances. The projected change in climate will vary depending on geographic location. Vulnerability assessments and adaptation strategies are needed at the local level to inform local management decisions and help ameliorate the effects of climate change on rangelands. The USDA Southwest Climate Hub and Natural Resources Conservation Service (NRCS) worked together to produce two drought vulnerability assessments at the Major Land Resource Area (MLRA) level based on ESs/STMs that will help landowners and government agencies identify and develop adaptation options for drought on rangelands. These assessments show how site-specific information can be used to help minimize the effects of drought on rangelands and support informed decision-making for selecting management adaptations within MLRAs.

Two reports are available: Southeast Arizona and Southwest New Mexico (MLRA 41) and Southeastern Colorado (MLRA 69).

The information in these reports is also offered in summarized form as ArcGIS StoryMaps and StoryMap Journals. The StoryMap give overviews of why drought poses such a difficult challenge to managers, and how policymakers, advisors and ranchers can develop responses to drought to help ensure sustainability.  The StoryMap Journals go into more detail, discussing how Ecological Sites can be used to determine the effects of drought on rangelands, for developing and implementing ranch level responses and for conducting vulnerability assessment.