Runoff contaminated with chemicals, including salt, affects roadside vegetation. Most of the documented effects occur at the road-segment level, which includes the road, roadside, and a zone described as the effective road-impact zone (Forman et al. Busy transport links stimulated the growth of cities, especially New York and Chicago, but also strategically located towns like Buffalo; Cleveland, Ohio; Pittsburgh, Pennsylvania; and St. Louis, Missouri. Virtually all of the world’s remaining wildernesses are under assault by road building—from the Amazon to New Guinea, and from Siberia to Sub-Saharan Africa. 1991, Brandenburg 1996). As a result, we’re witnessing an epic slaughter of forest elephants—killed by poachers for their valuable ivory tusks. Poorly designed engineering structures can often hinder the ecological improvements for which they were designed. In addition, new roads often are associated with development of residential, commercial, and industrial activities. Click here to obtain permission for Assessing and Managing the Ecological Impacts of Paved Roads. need to assess project-level effects of road building and expansion on species and their populations as part of policy guidelines (the National Environmental Policy Act and the Endangered Species Act) has been the catalyst for most single-segment and intermediate-scale studies (Evink 2002). In an aquatic culvert system, for example, several key design characteristics ensure effective utilization by the target species (see Box 3-1 under Biotic Consequences). One example is the set of effects on hydrological systems, where sediments, nutrients, and heavy metals are introduced into riparian systems. In addition, insects and pathogens can be transported into new environments by vehicles (NRC 2002). An analysis of the total effect of The Netherlands’s most dense network of main roads on “meadow birds” showed a possible population decrease of 16%, attributable to reduced habitat quality and traffic noise (Reijnen et al. The effect of distance varies, depending on the organism, location, and disturbance type, and generally increases with traffic volume (Clark and Karr 1979, Reijnen and Foppen 1994, Nellemann et al. Do you want to take a quick tour of the OpenBook's features? Chemical pollution from vehicle exhaust (primarily NOX) enriches roadside soil and changes plant composition, favoring a few dominant flowering plants at the expense of more sensitive plant species (for example, ferns, mosses, and lichens). Code of Ethics. Register for a free account to start saving and receiving special member only perks. Abiotic conditions that can be influenced by roads include hydrological, geomorphological, and chemical characteristics and such disturbances as landslides, noise, and light. (a) Upstream-downstream (1), floodplain-stream (2), forest-stream (3), and surface-subsurface water connections (4). 2002, Delfino et al. The dynamic aspects of these condition measurements are discussed later in the chapter where both spatial and temporal dimensions are addressed. The largest number of studies reporting on the chemical characteristics of road effects focus on the chemical effects arising from rainfall events at the single-segment scale (FHWA 1981; Asplund et al. The federal government paid for one major highway during this era, heading westward from Cumberland, Maryland, at the inland headwaters of the Potomac River. Many ecological effects of roads eventually influence structures and processes at longer and broader scales than first imagined. Integrating environmental considerations into all phases of transportation is an important, evolving process. William F. Laurance is a Distinguished Research Professor and Australian Laureate at James Cook University in Cairns, Australia. The rest of the state of New York—especially cities along the canal route, such as Rochester and Syracuse—also prospered.Other state governments hoped to replicate New York’s success, leading to a furious round of publicly financed canal projects. The ecological effects of roads are much larger than the roads themselves, and the effects can extend far beyond ordinary planning domains. 2001, Buckeridge et al. Verges also aid in the spread of plant spe-. Each level of biotic components has attributes of composition, structure, and functioning, and together constitute biological diversity (often called “biodiversity”). A short summary of effects on ecological goods and services is provided in the third section. This road-avoidance zone contributes to the road-effect zone. As discussed above, these efforts have produced a substantial body of literature that documents the effects of roads and traffic on ecological conditions. Physical disturbance can disrupt ecological systems, and roads promote such disturbances. Roads have effects that can vary with a range of spatial scales. across much of the southeast, invading areas never imagined in original assessments. We have our work cut out for us—trying to feed and sustain a hungry planet while saving a place for nature. Studies assessing ecological effects are often based on small sampling periods and, therefore, do not adequately sample the range of variability in ecological systems. It identifies the ecological effects of roads that can be evaluated in the planning, design, construction, and maintenance of roads and offers several recommendations to help better understand and manage ecological impacts of paved roads. The global population of forest elephants has plummeted by two-thirds in the last decade, along with many other wildlife species. Ambassador Kenneth... Road-killed tapir in Peninsular Malaysia (photo © WWF-Malaysia/Lau Ching Fong), Located in the wrong places, roads can open a Pandora’s Box of problems, says William F. Laurance. There also is a strong correlation between concentrations of heavy metals and volatile matter in highway runoff (Flores-Rodriguez et al. 1996). For instance, traffic flow seems to have a non-linear relationship with accident rates, even though some studies suggest linear relationship with accidents. For example, in Virginia at the crossings of the Potomac and Rappahannock Rivers along the I-95 corridor, there are populations of eagles and osprey that feed on the fish near the road-bridge crossings. Not a MyNAP member yet? This section indicates that ecosystems are scale variant; that is, the cross-scale biological structures and processes cannot be easily aggregated from one scale to another but are dependent on the scale of focus. Improving farming in such areas can go a long way toward helping us meet global food demand, which is rising sharply because of rapid population growth and changing diets. Roadside verges (margins) can increase habitat diversity where there is little remaining natural or seminatural habitat. By continuing you agree to the use of cookies. Because roads affect variables that change slowly, such as geological formations, soil composition, and topography, they often produce top-down effects. Few other families can accomplish either, especially with respect to upstream movement. Thermal characteristics of the road surface cause accelerated snow melt (NRC 2003). Ecologists have long conducted studies on species diversity patterns at broad spatial and temporal scales (Brown and Lomolino 1998). 2003). A minimum two-lane road is provided for national highways. Traffic-related mortality has contributed to the decline of several species: Eurasian badger (Meles meles) (Bekker and Canters 1997) and moor frog (Rana arvalis) (Vos and Chardon 1998) in The Netherlands, Hermann’s tortoise (Testudo hermannii) (Guyot and Clobert 1997) in southern France, and Florida panther (Felis concolor coryi) (Maehr et al. Ecological (or ecosystem) functioning refers to the ecological and evolutionary processes acting among the elements, or how the ecosystem works. The first transcontinental line was established in 1869 when the Central Pacific and Union Pacific lines met. Over the past two decades, the Federal Highway Administration and state transportation agencies have increasingly recognized the importance of the effects of transportation on the natural environment. The opening of the National Road saw thousands of travelers heading west over the Allegheny Mountains to settle the rich land of the Ohio River Valley. Roads change the albedo (fraction of light reflected by a surface) and other surface characteristics, but other structures, such as buildings, parking lots, and sidewalks, also contribute to heat-island effects. Jeanna Sullivan, National Geographic Society, Sarah Appleton, National Geographic Society The pipe mouth eventually extends out over the stream, creating a vertical drop while lacking the rock face characteristic of a natural waterfall. The Army Corps of Engineers began building the Cumberland Road, also called the National Road, in 1811. 2003. In this section, the committee considers only changes to the abiotic conditions themselves, and examples of each are provided below. (See Figure 6-4 for another plot of spatial scales by the U.S. Department of Defense.) The committee developed an annotated bibliography (Appendix B) of road effects on ecological conditions, with an emphasis on spatial scale. Within each subcategory, the effects of roads on structure, functioning, and composition were documented. Roads can help rural farmers, such as these small-scale settlers in Gabon, to boost their productivity and incomes (photo by William Laurance). More research should be directed at identifying the appropriate scale at which roads affect ecological conditions. Although current research is making valuable contributions, its ultimate impact is limited by low funding, inadequate coordination across research entities, and short-term or project-specific focus (TRB 2002a). Few studies address the complex nature of the ecological effects of roads. Examples of the use of these structures for ecological improvements are identified in Chapter 4 of this report. Also, in the arid west, the productivity of desert vegetation can be markedly greater near the roadside (Johnson et al. For example, little is known about how roads impede access to foraging areas or key prey species, potentially resulting in cascading or other trophic effects. The focal area of the review was North America, but research findings from Europe and Australia were also included. Understanding the difference between environmentally ‘good’ roads and ‘bad’ roads is vital, because we are currently living in the most explosive era of road building in human history. Reports typically include findings, conclusions, and recommendations based on information gathered by the committee and the committee’s deliberations. Roads affect ecosystem goods and services in many ways. It all comes down to the local context. The majority of these studies examined the impact of vehicular traffic on the presence or absence of volatile organic compounds (VOCs) (Clifford et al. In this chapter, the committee addresses the following two questions as stated in its charge: What are the appropriate spatial scales for different ecological processes that might be affected by roads? Pollutants that accumulate on roadways from spills, wastes generated during vehicle use, litter, and adjacent land uses enter waterways via surface runoff.

Porter Robinson Store, Words With These Letters, Is Whole Wheat Pasta Healthy, Captain Fantastic Amazon Prime, Sam Hargrave Net Worth, Nuclear Test Case Pdf,