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ScholarsArchive at Oregon State University
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In grasslands, grazing by large ungulates can influence vegetation structure, composition, primary productivity, and ultimately, ecosystem functioning. While grazing represents a complex disturbance, grazing intensity largely determines the...
2011-01-19 (iso8601)
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The quality and availability of forage fishes and invertebrates can affect the behavior and productivity of predators that rely on these resources. This study measures the proximate composition of forage fishes and invertebrates from the...
2011-01-19 (iso8601)
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Native bees play an important role as pollinators of natural vegetation and agricultural
crops. Yet many pollinators, including some native bees, are declining in numbers.
Some of the potential causes of these declines are habitat destruction and...
2011-01-19 (iso8601)
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In spite of considerable efforts to restore natural runs of anadromous
salmonids in the Pacific Northwest, they remain at risk of extirpation. Along
with many other factors influencing the decline, stocking from hatcheries
over the past hundred...
2005-06-08 (iso8601)
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Greater sage-grouse (Centrocercus urophasianus) populations declined range wide
during the past 50 years. Grouse populations were 2-3 times larger than the current
population as recently as the early 1970's. In addition to habitat loss and...
2006-05-02 (iso8601)
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Bullfrogs were introduced into Oregon in the early 1900s and have become widespread
members of many wetland communities. Little is known of their ecology outside their native range,
although they may play a role in the current declines observed in...
2004-01-23 (iso8601)
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In the fall through spring of 2002/03 and 2003/04, the composition of
fish and amphibian communities were examined in intermittent streams in
the upper Willamette river basin in western Oregon. I recorded standard
aquatic habitat variables and...
2005-05-04 (iso8601)
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Chinook salmon (Oncorhynchus tshawytscha) have been absent from their
historic spawning and rearing grounds in the Metolius River Basin in central Oregon
since 1968, when fish passage was terminated at the Pelton Round Butte Hydroelectric
Project...
2005-03-17 (iso8601)
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I examined hydrological and plant community changes associated with the
implementation of a restoration management plan in two riparian meadows
located within an agricultural landscape of the central Willamette Valley, Oregon.
I established...
2004-01-08 (iso8601)
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Estuaries provide juvenile salmonids with highly productive feeding grounds,
refugia from tidal fluctuations and predators, and acclimation areas for smoltification.
However, these dynamic, fluctuating salinity environments may also be...
2005-01-06 (iso8601)
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1997-03-11 (iso8601)
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Twentieth century commercial whaling drastically reduced the abundance of great whale populations in the Southern Ocean. Exploitation began on the south Atlantic island of South Georgia, where catch records account for over 175,000 whales killed....
2011-02-08 (iso8601)
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In an effort to identify seasonal distribution patterns and habitat requirements of coastal
cutthroat trout Oncorhynchus clarki clarki, movement of tagged and marked individuals
(35 radio-tagged, 753 PIT-tagged, and 5,322 fin-clipped) was...
2002-06-06 (iso8601)
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Both leave islands, or green tree retention clusters, and thinning prescriptions
have been proposed as alternative silvicultural strategies designed to sustain the
structural and biological diversity of managed forests. However, the relationship...
2005-06-17 (iso8601)
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Invasion by nonnative brook trout (Salvelinus fontinalis) often results in
replacement of bull trout (Salvelinus confluentus) in western North America, but the
causal mechanisms are not well understood. Removal of brook trout from 1992 to 2000...
2005-06-07 (iso8601)
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Streams in the Alsea and Nestucca Sub-Basins were characterized using suites of
habitat attributes at the pool and reach scales. These suites were analyzed using a
multivariate process with the Multiple Response Permutation Procedure (MRPP)
to...
2005-06-02 (iso8601)
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Relatively little is known about wintering bird communities in lowlands of
the Pacific Northwest, yet, the condition of winter habitats potentially can pose a
major constraint on bird populations. I initiated a study to determine: (1) Which
avian...
2002-01-28 (iso8601)
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I investigated Caspian terns (Sterna caspia) breeding at colonies on the
Columbia Plateau (southeastern Washington and northeastern Oregon), with
emphasis on the breeding and foraging ecology of Caspian terns nesting at
colonies in the...
2002-10-16 (iso8601)
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The littoral zones of seven reservoirs in the southern Willamette Valley of Oregon
were sampled with a boat electroshocker during the summer months of 1995 and 1996.
Shoreline substrates were inventoried before sampling sites were randomly...
2002-04-19 (iso8601)
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The Tillamook and Kilchis subbasins of the Tillamook Bay watershed (Oregon
Coast Range) have differences in geology and land use history and, therefore, varied
environmental conditions that could affect fish assemblages. Fifty-two randomly...
2000-03-07 (iso8601)
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