Abstract:
This study describes streams in the Blue Mountains and Wallowa Mountains of Northeastern Oregon in order to characterize the interactions between the terrestrial and aquatic ecosystems and to determine how logging affects those relationships. Five stream reach pairs, each consisting of an undisturbed reach and a similar reach flowing through an area where the riparian zone had been logged, along with six additional undisturbed reaches were studied. The riparian stand, large woody debris, stream channel morphology and the benthic macroinvertebrate community were measured at each reach. Large woody debris volume ranged from 91.1 to 284.0 m³/ha and was greater in the logged reaches than undisturbed reaches. Stream channel morphology, as indicated by the pool-riffle ratio, in the logged reaches was not significantly different than undisturbed reaches and percent pool area was less than 30 percent in all reaches.
Macroinvertebrate density ranged from 146.6 to 963.2 individuals/sample and was greater in the logged reach of each stream pair. Community diversity, as expressed by the Shannon-Wiener Diversity Index, at logged reaches was not significantly different from that at undisturbed reaches. Although some differences were found between logged stream
reaches and undisturbed reaches, there was no indication that overall fish habitat was greatly diminished or improved as a result of
logging.
