350
E .D. Hetherington
What has been the net effect of logging-related effects on young salmon
life stages on the numbers of adult salmon returning to spawn in the
creek? This question is more difficult to answer because of the impacts of
ocean conditions and fishery exploitation on salmon survival outside the
confines of the creek. Through the use of models that can partition the
various factors, it appears that logging has had only a small negative
effect (-5%) on returning numbers of adult coho but a larger adverse
impact (-26%) on the chum salmon (Scrivener, 1990). In contrast to the
coho which rear in the stream, the chum leave the creek after emerging in
the spring and appear to have been mainly affected by the deterioration
of spawning gravel quality. Annual variability in returning populations
has increased since logging. The results suggest that logging impacts on
the salmon are strongly conditioned by environmental and climatic factors.
Summary
Long-term studies are necessary for a proper understanding and quantification of the effects of land use practices such as logging on the complex physical and biological processes of stream ecosystems. Variations in
climate and time required for recovery from disturbance are but two of
the many factors that require a lengthy record to be properly evaluated.
These factors alone are sufficient to justify continued monitoring at Carnation Creek. Other supportive arguments include the absence of other
similar long-term studies in coastal British Columbia, the recognition that
long-term records are required to document climate change and its implications for natural ecosystems, and the value of long-term records for
extrapolating short-term hydrometeorological measurements. Long-term
data records are scarce, particularly in mountainous areas, and are
becoming more and more valuable as we attempt to understand and
define the impacts of both man's activities and broader climatic changes
on forested ecosystems.
References
Bosch, J .M., and . Hewlett, J.D. 1982. A review of catchment experiments
to determine the effect of vegetation changes on water yield and evapotranspiration. J Hydrol , 55, 3-23.
Bustard , D.R., and Narver, D.W. Preferences of juvenile coho salmon (Oncorhynchus kisutch) and cutthroat trout (Salmo clarki) relative to simulated
alteration of winter habitat. J Fish Res Board Can, 32,681-687.
Harr, R.D. 1982. Fog drip in the Bull Run municipal watershed, Oregon . Wat
Resour Bull, 18(5), 785-789.
Harr, R.D. 1986. Effects of clearcutting on rain-on-snow runoff in western
Oregon: a new look at old studies. Wat Resour Res 22(7), 1095-1100.
Harr, R.D. , Fredrick sen, R .L., and Rothacher, J . 1979. Changes in Streamflow
Following Timber Harvesting in Southwest Oregon. Portland, Or: V .S.D.A. ,
E .D. Hetherington
What has been the net effect of logging-related effects on young salmon
life stages on the numbers of adult salmon returning to spawn in the
creek? This question is more difficult to answer because of the impacts of
ocean conditions and fishery exploitation on salmon survival outside the
confines of the creek. Through the use of models that can partition the
various factors, it appears that logging has had only a small negative
effect (-5%) on returning numbers of adult coho but a larger adverse
impact (-26%) on the chum salmon (Scrivener, 1990). In contrast to the
coho which rear in the stream, the chum leave the creek after emerging in
the spring and appear to have been mainly affected by the deterioration
of spawning gravel quality. Annual variability in returning populations
has increased since logging. The results suggest that logging impacts on
the salmon are strongly conditioned by environmental and climatic factors.
Summary
Long-term studies are necessary for a proper understanding and quantification of the effects of land use practices such as logging on the complex physical and biological processes of stream ecosystems. Variations in
climate and time required for recovery from disturbance are but two of
the many factors that require a lengthy record to be properly evaluated.
These factors alone are sufficient to justify continued monitoring at Carnation Creek. Other supportive arguments include the absence of other
similar long-term studies in coastal British Columbia, the recognition that
long-term records are required to document climate change and its implications for natural ecosystems, and the value of long-term records for
extrapolating short-term hydrometeorological measurements. Long-term
data records are scarce, particularly in mountainous areas, and are
becoming more and more valuable as we attempt to understand and
define the impacts of both man's activities and broader climatic changes
on forested ecosystems.
References
Bosch, J .M., and . Hewlett, J.D. 1982. A review of catchment experiments
to determine the effect of vegetation changes on water yield and evapotranspiration. J Hydrol , 55, 3-23.
Bustard , D.R., and Narver, D.W. Preferences of juvenile coho salmon (Oncorhynchus kisutch) and cutthroat trout (Salmo clarki) relative to simulated
alteration of winter habitat. J Fish Res Board Can, 32,681-687.
Harr, R.D. 1982. Fog drip in the Bull Run municipal watershed, Oregon . Wat
Resour Bull, 18(5), 785-789.
Harr, R.D. 1986. Effects of clearcutting on rain-on-snow runoff in western
Oregon: a new look at old studies. Wat Resour Res 22(7), 1095-1100.
Harr, R.D. , Fredrick sen, R .L., and Rothacher, J . 1979. Changes in Streamflow
Following Timber Harvesting in Southwest Oregon. Portland, Or: V .S.D.A. ,