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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #270916
Title: Assessing impacts of roads: Application of a standard assessment protocol

Author
item DUNIWAY, MICHAEL - Us Geological Survey (USGS)
item Herrick, Jeffrey - Jeff

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2012
Publication Date: 5/1/2013
Citation: Duniway, M.C., Herrick, J.E. 2013. Assessing impacts of roads: Application of a standard assessment protocol. Rangeland Ecology and Management. 66:364-375.

Interpretive Summary: Managing the increasing number of roads in rangelands requires accurate information on their impacts. This paper describes development and testing of an approach to apply a commonly applied rangeland assessment protocol (Interpreting Indicators of Rangeland Health) to roads. The test application on a semi-arid landscape in southern New Mexico, USA demonstrates that the approach developed is sensitive to road impacts across a broad range of ecological sites but that not all the types of stratification were useful. Landscape-scale analysis of impacts by roads of contrasting designs (maintained dirt or gravel roads versus non- or infrequently maintained roads) suggests that future travel management plans for the study area should consider concentrating traffic on fewer roads that are well-designed and maintained.

Technical Abstract: Adaptive management of road networks depends on timely data that accurately reflect the impacts of network impacts on ecosystem processes and associated services. In the absence of reliable data, land managers are left with little more than observations and perceptions to support adaptive management of road-associated disturbances. Roads can negatively impact the soil, hydrologic, plant, and animal processes on which virtually all ecosystem services depend. The Interpreting Indicators of Rangeland Health (IIRH) protocol is a qualitative method that has been demonstrated to be effective in characterizing impacts of roads. The goals of this study were to develop, describe, and test an approach for using IIRH to systematically evaluate road impacts across large, diverse arid and semiarid landscapes. We developed a stratified random sampling approach to plot selection based on ecological potential, road inventory data, and image interpretation of road impacts. The test application on a semi-arid landscape in southern New Mexico, USA demonstrates that the approach developed is sensitive to road impacts across a broad range of ecological sites but that not all the types of stratification were useful. Ecological site and road inventory strata accounted for significant variability in the functioning of ecological processes but stratification based on apparent impact did not. Analysis of the repeatability of IIRH applied to road plots indicates that the method is repeatable but consensus evaluations based multiple observers should be used to minimize risk of bias. Landscape-scale analysis of impacts by roads of contrasting designs (maintained dirt or gravel roads versus non- or infrequently maintained roads) suggests that future travel management plans for the study area should consider concentrating traffic on fewer roads that are well-designed and maintained. Application of the approach by land managers will likely provide important insights into minimizing impacts of road networks on key ecosystem services.