Forman, R. T. T., and L. Alexander. 1998. Roads and their major ecological effects. Annual Review of Ecology and Systematics 29:207-231.

RELEVANT TO:

ROADS/OFF-ROAD VEHICLES

INVASIVE SPECIES

VEGETATION AND WILDLIFE

MONITORING/ADAPTIVE MANAGEMENT

DESCRIPTION

This article examines the major ecological effects roads have on the landscape. It documents that road densities and road networks can impact the ecological health of a landscape.

MAJOR FINDINGS

Some of the ecological effects of roads are:

  1. species-rich roadsides are conduits for few species
  2. roadkills are a premier mortality source, yet except for local spots, these rates rarely limit population size
  3. road avoidance due to traffic noise has a great ecological impact
  4. the barrier effect has even more impact, including subdividing populations, with demographic and probably genetic consequences
  5. road networks cause local hydrologic and erosion issues
  6. chemical pollution from roads usually occurs within a short distance from the road
  7. road networks interrupt horizontal ecological flows and alter landscape spatial patterns, and therefore can inhibit important interior species
  8. road density and road network structure can impact the ecological health of a landscape
  9. some countries have set aside large roadless reserves or constructed tunnels and overpasses across roads to enhance ecological flows
  10. based on road-effect zones, an estimated 15-20% of the United States is ecologically impacted by roads.

QUESTIONS RAISED FOR THE THREE FORESTS

  1. Has the Forest calculated road densities, using both Forest-maintained and user-created routes?
  2. What are acceptable road densities in this region relative to other forest uses and non-use values? How do they vary by Geographic Area?

RELEVANCE TO FOREST MANAGEMENT

As the road issue is addressed in the management process, consideration should be given to road densities as well as the fragmentation effect roads cause.

Start with a "blank map" for road/routes; add roads that are non-redundant, necessary, and least degrading of the environment; close redundant and spur roads.