This thesis provides the first general description of the natural variation in age
structure, growth rates, and survival in headwater populations of coastal cutthroat
trout Oncorhynchus clarkii clarkii from western Oregon, and a subsequent
synthesis of these life-history characteristics across the range of the subspecies.
Age, growth, and survival were...
Channels that were scoured to bedrock by debris flows provided unique opportunities to calculate the rate of sediment and wood accumulation, to make inferences about processes associated with input and transport of sediment, and to gain insight into the temporal succession of channel morphology following disturbance. In an intensive investigation...
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 monitored over a 14-month period in an isolated watershed in southwestern Oregon. Emigration out of the basin was...
Mark-recapture methods were used to examine watershed-scale survival rates of coastal cutthroat trout (Oncorhynchus clarkii clarkii) from two headwater stream networks located in the foothills of the Cascade Mountain Range, Oregon. Differences in survival were explored among spatial (stream segment, stream network [main stem or tributaries], and watershed) and temporal...
Wildfire is a largely terrestrial perturbation broadly recognized as an agent of disturbance and ecological change in forested biomes. Effects of post-fire conditions on biotic components of aquatic systems have been less well-documented, although hypothetically, the two are strongly connected. In fact, the influence of wildfire may be most profound...
Radiotelemetry was used to study the seasonal movements and habitat use of adult westslope cutthroat trout Oncorhynchus clarki lewisi in Roberts
Creek and Rail Creek, headwater tributaries of the John Day River, Oregon,
from September 2000 to December 2001. The objectives were to (1)
describe adult cutthroat trout life history...
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Robert E. Gresswell
Radiotelemetry was used to study the seasonal movements and habitat use
Previous research in South Fork Hinkle Creek suggested that coastal cutthroat trout exhibit an aggregated spatial pattern across multiple spatial scales. To evaluate the persistence of the observed abundance patterns and identify factors that affect those patterns, half-duplex passive integrated transponders (PIT-tags) were implanted in 320 coastal cutthroat trout (>...
The distribution of Lahontan cutthroat trout Oncorhynchus clarki henshawi was assessed in a high-desert stream in southeastern Oregon where beaver Castor canadensis are abundant. Longitudinal patterns of beaver ponds, habitat, temperature, and Lahontan cutthroat trout age group distribution were identified throughout Willow Creek. Three distinct stream segments were classified based...
Current riparian management objectives in the Pacific Northwest promote both retention of existing conifers and conversion of hardwood-dominated areas to conifers. Although understanding of relationships between riparian vegetation and salmonid prey availability is growing, temporal variation in these relationships is poorly understood. Seasonal fluxes in availability of aquatic and terrestrial...
Although the effects of extrinsic barriers to dispersal have increasingly been shown to
play a large role in the structuring of contemporary genetic diversity, describing the
relationship between landscape structure, stochastic disturbance, and genetic diversity
remains a major challenge. Here, environmental features for 27 barrier-isolated
populations (2,232 individuals) of coastal...
