Environmental Management

, Volume 19, Issue 4, pp 609–621

Equivalent roaded area as a measure of cumulative effect of logging

Authors

  • Bruce J. Mcgurk
    • Pacific Southwest Research StationUSDA Forest Service
  • Darren R. Fong
    • USDI National Park ServiceGolden Gate NRA
Article

DOI: 10.1007/BF02471972

Cite this article as:
Mcgurk, B.J. & Fong, D.R. Environmental Management (1995) 19: 609. doi:10.1007/BF02471972

Abstract

A watershed disturbance index developed by the USDA Forest Service called equivalent roaded area (ERA) was used to assess the cumulative effect from forest management in California's Sierra Nevada and Klamath mountain ranges. The basins' ERA index increased as logging and road-building occurred and then decreased over time as management ceased and vegetation recovered. A refinement of the standard index emphasized disturbances in sensitive, near-channel areas, and evaluated recovery periods of 20, 30, and 50 years. Shorter recovery periods yielded better correlations between recovering forest systems and aquatic response than the longer recovery period, as represented by ERA and diversity or dominance, respectively. The refined ERA index correlated more closely with macroinvertebrate dominance and diversity information that was available for part of the study period. A minimum ERA threshold of 5% was detected, below which no effect to the macroinvertebrate community was observed. Above this threshold, elevated ERA values were associated with a decline in macroinvertebrate diversity and an increase in dominance of the top five taxa. Use of an ERA technique that emphasizes near-channel areas and biological thresholds would contribute to the Forest Service's implementation of ecosystem management.

Key Words

Cumulative effectCumulative watershed effectEcosystem managementLoggingEquivalent roaded areaAquatic macroinvertebrate

Copyright information

© Springer-Verlag New York Inc. 1995