Surface Transportation Environmental Research A Long-Term Strategy -- Special Report 268 (2002) / Chapter Skim
Currently Skimming:
3 Research Area 2: Ecology and Natural Systems
3 Research Area 2: Ecology and Natural Systems
Pages 58-77
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 58... ...
The numbers of vehicles, vehicle-miles traveled (VMT) , and traffic jams have continued to increase, along with resultant air pollutants, traffic noise, water-transported chemicals, barriers to wildlife crossing, and pressure for additions to the road network.
|
From page 59... ...
Fortunately, nature is resilient. Although the degradation is sub stantial, much can be done to mitigate the damage to groundwater, biodiversity, soil surfaces, native vegetation, streams, lakes, fish, and wildlife populations caused by surface transportation.
|
From page 60... ...
An array of invis ible chemicals has blanketed the roadside and penetrates the forest; heavy metals such as zinc and cadmium, nitrogen oxides, hydrocarbons, herbicides, (continued)
|
From page 61... ...
SURFACE TRANSPORTATION AND NATURAL SYSTEMS As discussed earlier, although surface transportation includes rail corridors and managed waterways with barge transport, the focus here is on road sys tems. Four major groups of issues highlight the close linkage between road transportation and natural systems.
|
From page 62... ...
. Many aspects remain as little-explored frontiers: rare plants; habitat heterogeneity related to construction, mowing, maintenance, and management regimes; exotic species invading from roadsides to sur rounding lands; the barrier effect on wildlife movement (Fahrig et al.
|
From page 63... ...
Some of the direct effects of this runoff on certain plant and animal species have been identified, but most contaminantspecies interactions remain unknown. Perhaps more important, the direct effects of highway runoff on patterns and processes of aquatic ecosystems are poorly understood.
|
From page 64... ...
Research appears to be scarce as well on the effects of particulates on wildlife populations, and on the eco logical effects of hydrocarbons and certain heavy metals. Landscape Ecology of Transportation Systems Landscape ecology is a rapidly developing body of knowledge and research that represents a relatively new, highly useful, and far-reaching dimension for consideration in transportation planning and activity.
|
From page 65... ...
provides principles and models that directly address habitat fragmentation, arrangements of green patches, wildlife corridors for foragingdispersal migration, groundwater and surface-water flow paths, effects of small pop ulations in enclosed polygons, remote-area impacts due to human access, sources and sinks in the landscape, changing spatial patterns over time, and ecologically optimum spatial models (Forman 1995; Reed et al. 1996; Turner et al.
|
From page 66... ...
While they represent largely new initiatives, the proposed work would build on strong foundations in transportation research in such areas as hydrology, sediment flow, roadside vegetation management, roadkills, traffic flows, and pollutant emissions. Funding agencies and sources both inside and outside the transportation field have shown little interest in supporting the proposed research; thus very little research is being done in most of these areas.
|
From page 67... ...
Expand research efforts aimed at understanding wildlife movement near corridors, roadkill rates, and road-barrier effects and at develop ing efficient mitigation designs for road crossing by animals. Although crashing into a large animal with a motorized vehicle may involve damage, human injury, or death (Conover et al.
|
From page 68... ...
Striking research gaps in knowledge also exist, however. For example, how does the arrangement of the surrounding landscape, including wildlife movement corridors, affect where different species tend to cross roads (Evink et al.
|
From page 69... ...
How highway runoff might be modified to mitigate roadhydrology impacts remains a challenge, however, because that goal can be attained only through a better understanding of the specific effects of changing hydrology on aquatic ecosystems. Thus the effects of varying highway runoff levels on the stability of channels or the functioning of wetlands cannot be predicted.
|
From page 70... ...
Major and visible effects -- such as shoreline alteration, reduced connection to adjacent upland, sediment filling-in, eutrophication, reduced oxygen levels, and altered fish populations -- are attributable to roads altering coastal, lake, reservoir, pond, and vernal-pool ecosystems. Similarly, stream and river water quality is significantly altered by roads, as illustrated by bridge effects, eroded sediments, turbidity, reduced diversity of stream habitats, warm water from roadside ditches, movement of chemical substances, truncated food webs, and altered fish populations (FHWA 1996; Findlay and Houlahan 1996; Evink et al.
|
From page 71... ...
The contaminants in high way runoff have also been widely characterized, though much remains poorly known. For example, the specific ecosystem effects of highway runoff and their relative contribution to overall environmental quality in receiving waters remain elusory.
|
From page 72... ...
Perhaps most is known about the ecological effects of salt, herbicides, sulfur dioxide, and some heavy metals. At least some useful ecological information is probably available on the remaining air pollutants.
|
From page 73... ...
. Road networks also disrupt nature's networks of green patches and corridors across the landscape, while remote roads built to pro vide human access result in disturbance to natural populations and communities.
|
From page 74... ...
Foster collaborative landscape-wide environmental analyses by engi neers, ecologists, and planners, with an emphasis on combining eco logical solutions with other societal objectives. Landscape ecology integrates traditional ecology with spatial patterns at the landscape or regional scale, precisely the scale of road systems (Forman 1995, TRB 1997)
|
From page 75... ...
Yet to set plan ning and policy priorities for addressing the diverse dimensions of natural sys tems, it is important to consider people's preferences and consequent public support when allocating scarce resource dollars. The research challenge includes not only understanding the attitudes of different groups of people, but also determining what is included in the valuation and developing the best method ologies for conducting the valuation.
|
From page 76... ...
1996. Evaluation and Management of Highway Runoff Water Quality.
|
From page 77... ...
2001. Management of Runoff from Surface Transportation Facilities, Synthesis and Research Plan.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.