Disentangling road network impacts: The need for a holistic approach

Authors: Duniway, Michael; Herrick, Jeffrey - Jeff

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2010
Publication Date: 3/15/2011
Citation: Duniway, M.C., Herrick, J.E. 2011. Disentangling road network impacts: The need for a holistic approach. Journal of Soil and Water Conservation. 66(2):31A-36A.

Interpretive Summary: The scale and rate of development of linear disturbances has increased dramatically in the past decade. For effective local to landscape scale management of transportation networks, a holistic approach is needed that accounts for how roads, trails, and other development activities directly and indirectly alter ecosystem services. The objective of this paper is to define the elements of analysis that can be used to systematically predict, assess, and minimize road impacts on ecosystem services across multiple spatial scales. The approach advocated here begins with a comprehensive understanding of how roads impact ecosystem processes in the management area. This understanding allows for prediction of road impacts at various spatial scales across the landscape. Prediction of road impacts is important for both planning new development and designing assessment and monitoring programs. Predictions could be used to design road networks that avoid critical areas that lead to strong non-linear impacts on ecosystem processes. Similarly, predictions could be used for designing cost effective assessment and monitoring programs that capture road impacts at the relevant scale.

Technical Abstract: Traditional and alternative energy development, logging and mining activities, together with off-highway vehicles (OHV) and exurban development, have increased the density of linear disturbances on public and private lands throughout the world. We argue that the dramatic increase in linear disturbances occurring globally has the potential to drastically alter landscape ecosystem processes, including soil and water conservation, and thus presents one of the greater challenges faced by natural resource scientists today -- a challenge we are poorly prepared to meet. Analytical tools and data are needed to systematically predict, assess, and minimize the impacts of these linear disturbances. The objective of this paper is to define the elements of analysis that can be used to systematically predict, assess, and minimize road impacts on ecosystem services across multiple spatial scales. The elements we outline are (1) identifying direct effects, (2) describing spatial interactions, (3) defining feedbacks among processes, (4) defining interacting effects of other stressors, (5) the extent to which these effects vary spatially (e.g. among units) and (6) thresholds and other non-linear responses. These elements can serve as the foundation for focusing monitoring efforts on those areas most likely to experience the greatest change in ecosystem processes and, similarly, target mitigation to areas with the greatest potential for recovery. The focus of this paper is on unimproved, unpaved roads in arid and semi-arid ecosystems; however, the general approach is relevant for most ecosystems and to all linear disturbances.