Assessing Impacts of Roads: Application of a Standard Assessment Protocol

Abstract

Adaptive management of road networks depends on timely data that accurately reflect the impacts those systems are having 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 management decisions 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 goal 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 semiarid landscape in southern New Mexico, United States, 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 on 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 vs. 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.

Quantifying and mapping ecosystem service use across stakeholder groups: Implications for conservation with priorities for cultural values

“…Perhaps somewhat surprisingly, none of the identified ES hotspots were located in currently protected areas; possibly due to inaccessibility. The importance of ES proximity to roads was highlighted by Chan et al (2006) and Fagerholm et al (2012), suggesting there may be trade-offs in trying to achieve a high level of both biodiversity and ES in the same area, since roads are also known to negatively impact biodiversity along with many of the biological processes and functions that ES depend upon (Duniway and Herrick, 2013). A recent review by Mitchell et al (2013) revealed that there is little known regarding how connectivity and road access affect ES delivery (especially for cultural ES and provisioning ES), and that links between cultural ES and connectivity have never been tested.…”

Ecological site‐based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands

“…Soil and vegetation attributes were sampled at 120 plots as part of a broader study to evaluate the sensitivity of a standard rangeland assessment protocol to road impacts (Duniway and Herrick 2013). The plots were stratified across five types of ecological site with similar potential vegetation composition and vegetation production ( Table 1; Appendix: Table A1).…”

The inclusion of stakeholders and cultural ecosystem services in land management trade-off decisions using an ecosystem services approach

“…Further, our work suggests that most participants who perceived an increase in ecosystem services were in favour of increased road development to access ecosystem services. Many previous studies suggest road access is important for many provisioning ecosystem services (Chan et al 2006;Wang et al 2010;Fagerholm et al 2012;Cimon-Morin et al 2013), yet roads are known to negatively impact regulating and supporting ecosystem services through degradation to plant, animal, soil and hydrologic processes (Benítez-López et al 2010;Duniway and Herrick 2013). Different stakeholder groups may have different influence in management decisions despite all having strong interest, value or use of ecosystem services.…”