The migrations upstream of pre-spawned adult steelhead (Oncorhynchus mykiss) and
downstream of post-spawned steelhead (referred to as "kelts") can geographically and
temporally overlap in the Snake River, leading to management challenges for populations
listed under the Endangered Species Act (ESA). This thesis describes the development and
application of a method...
The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory...
I examined the relative roles of biotic and abiotic factors in structuring redband trout
Oncorhynchus mykiss distributions in the South Fork John Day. I first examined the
relationship between the biological traits of the fish assemblage and riparian-geomorphic features in context of prevailing theories of stream ecology stemming from the...
Partial migration is a common migratory behavior where some individuals in a population migrate and others do not. Patterns of partial migration can vary dramatically, especially for species that inhabit a wide range of environments. I described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss (steelhead...
The overall goal of this study was to identify multiple scales of habitat use and habitat electivity by redband/steelhead trout and define the limiting factors affecting the distribution patterns of this species during summer flows.
The main objective in chapter 2 was to identify the most important habitat associations that...
Vegetation provides food for many insects, and many insects serve as food for bats. We investigated the linkages among these three trophic levels in riparian areas throughout the Oregon Coast Range by examining the influence of vegetation cover, composition, and structure on the activity of nocturnal insects and bats, the...
Disturbance, whether natural or of human origin, modifies to varying degrees
many ecosystem attributes. Fire is a natural process in the montane forests of southern
Oregon but for much of the 20th century fire was viewed as an apocalypse and thus
fervently suppressed. Effective natural resource management requires an
understanding...
Because riparian canopy controls most energy inputs to stream
ecosystems, it directly affects the structure of aquatic food webs and the
ecological processes that govern interactions among trophic levels. This
study addresses the interdependence among riparian canopy, benthic
community structure, and the carrying capacity of high desert streams for
salmonid...