Equivalent roaded area as a measure of cumulative effect of logging |
| |
Authors: | Bruce J Mcgurk Darren R Fong |
| |
Institution: | (1) Pacific Southwest Research Station, USDA Forest Service, PO Box 245, 94701 Berkeley, California, USA;(2) USDI National Park Service, Golden Gate NRA, Fort Mason, 94123 San Francisco, California, USA |
| |
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. |
| |
Keywords: | Cumulative effect Cumulative watershed effect Ecosystem management Logging Equivalent roaded area Aquatic macroinvertebrate |
本文献已被 SpringerLink 等数据库收录! |
|