Accurately distinguishing species in the fossil record is difficult when the extent of osteological variation in many modern animals is unknown. Research into intraspecific variation has been conducted in a number of groups, but has not been conducted for systematics use in most modern artiodactyls. In this dissertation I quantify intraspecific variation of teeth in 14 species of modern artiodactyl, then test how accurately cranial characters diagnose modern, sympatric species of duikers, and use this information to reassess the artiodactyl diversity of a fossil group: the superfamily Merycoidodontoidea in the John Day Fossil Beds. Ultimately, variation is not constant between orders or different size classes, is influenced by morphology, size, and dimorphism, and this variation should be incorporated into fossil diagnoses to avoid both overconfidence of diagnosis and under-recognition of possible intraspecific variation.

Thesis (M.S. in geology)--Washington State University, May 2010. / Title from PDF title page (viewed on July 9, 2010). "School of Earth and Environmental Sciences." Includes bibliographical references (p. 105-117).

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 fishes. In streams in the lower John Day River Basin in eastern Oregon, algal, invertebrate, and fish communities were compared in reaches with varying densities of riparian canopy. Water temperatures varied with the density and upstream extent of canopy. Densely canopied sites were cool, while sites with high irradiances had temperatures exceeding the upper lethal limit for salmonids. Periphyton and grazer biomasses were greater in well-lighted sites, but 90% of grazer biomass consisted of Dicosmoecus gilvipes, a large caddisfly inedible by juvenile trout. Warmer water increased metabolic demands for salmonids, while the overwhelming dominance of Dicosmoecus in open sites shifted energy flow away from trout and shrunk their food base. High water temperatures, however, provided suitable habitat for many warmwater fishes which would otherwise not enter tributaries of this size. At higher elevation study sites in Camp Creek, light levels were higher and less variable than at the lower sites. Periphyton and invertebrate abundances were not correlated with irradiance. Rather, periphyton was maintained at low levels by grazers, particularly Dicosmoecus and snails. Manipulations of fish densities in enclosures showed that trout and dace had no negative impacts on numbers of invertebrate prey, and that grazers played a larger role in regulating lower trophic levels than did fish. Dicosmoecus acted as a keystone species in the benthic food web of Camp Creek by simultaneously influencing the trophic level both below and above its own. When irradiance was experimentally reduced under artificial canopies, periphyton standing crops were not different from those in open control pools after 4 wks. However, grazers were more abundant in open pools. The cropping of periphyton to uniform levels in both sunlight and shade indicated that mobile grazers targeted sites of varying productivities. Comparisons between benthic communities in Camp Creek and in a densely canopied reference stream suggested that benthic community structure shifted to accommodate changes in energy resources that occur when canopy density is altered. / Graduation date: 1998

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 120-125). Also available on the World Wide Web.

xii, 64 p. : ill. (some col.), maps / Salmon habitat restoration is ongoing at a Nature Conservancy preserve on the Middle Fork John Day River in the Columbia River Basin in north-central Oregon. The site has a long history of disturbance including dredge mining upstream, channelization, grazing, logging, fire, and floods. Using historic aerial photos, habitat unit surveys, and cross sectional profiles, this thesis shows how the channel morphology, particularly habitat unit diversity, has changed since 1939, just before placer mining began. Results show that the dominant influence on present day channel morphology is channelization from the 1930's. Other changes including dredge mining in the late 1930's to early 1940's, cessation of cattle grazing in 1991, and a fire followed by a flood in the winter of 1996-1997, had less impact because of the straightened, stabilized channel morphology. / Committee in charge: Patricia McDowell, Chairperson; W. Andrew Marcus, Member / 10000-01-01

I hypothesized that vegetation and physical environmental characteristics would differ between the upper and lower extents of the annually flooded riparian zone on the John Day River, and that relationships between species and environmental variables would display differences between these two zones. Vegetation, environmental variables, and relationships between them were assessed for the entire annually flooded riparian zone, and for the proposed upper and lower zones. Data were collected from 60 one-square-meter quadrats: 30 in each the upper and lower zones. Sites were randomly selected and located so that flood duration was roughly equal at all sites within each zone. 34 plant species were encountered: 25 in the upper zone, 27 in the lower zone. Wetland obligate and facultative wetland species groups and eight individual species accounted for statistically different percentages ofquadrat cover between zones. ANOSIM analysis identified two statistically distinct vegetation communities between the two zones. Soil texture averaged 75.85% sand and 20.81% fines. Sand ranged between 36.69% and 95.55%. Fines ranged between 2.54% and 58.84%. A horizon depths and fine soil particle concentrations were greater in the upper zone. Coarser soils with more sand and gravel dominated the lower zone. All enviromnental variables studied, except pH, were highly variable throughout the study area. ANOSIM analysis results suggest that the upper and lower zones have distinct, statistically different physical environments from each other. Regression analyses relating species quadrat cover to physical environmental variables were performed for the total, upper, and lower riparian zones. Numerous differences were identified between the upper and lower riparian zones that the riparian scale analyses did not represent accurately. There were ten instances in which the zone scale analyses identified a relationship in either the upper or lower zone, while the corresponding riparian scale analysis failed to identify any relationship. The results of this study indicate that vegetation and the physical environment are statistically different between the upper and lower zones on this river, and that relationships between a given plant species and environmental variable can vary between zones. Future research and management efforts should consider and address the potential for such between-zone variation.

This study examined the distribution and behavior of adult spring chinook salmon (Oncorhynchus tshawytscha) related to patterns of stream temperature and physical habitat at channel unit, reach, and basin-wide spatial scales in both a wilderness stream and a disturbed stream in the John Day River basin in northeastern Oregon. Thermal remote sensing of holding and spawning reaches in the upper subbasins of the North Fork and Middle Fork John Day River provided spatially continuous maps of stream temperature. Multiscale associations between salmon and cool-water areas were assessed by overlaying thermal imagery with fish locations mapped during distributional surveys. Chinook salmon were distributed non-uniformly throughout each study area, indicating that salmon selected certain reaches within each subbasin. The coldest reaches available to salmon within the Middle Fork study areas were low gradient, unconstrained reaches where the cooling influence of groundwater flow was the most apparent. In the Middle Fork, the stream currently managed for grazing and timber harvest, water temperature differences were typically 1-2��C within riffle-pool sequences and 3-4��C among reaches. The reach level association between salmon distribution and stream temperature patterns at channel unit and reach level spatial scales was strongest in the warmest study reach, the Middle Fork, and weakest in the coldest study reach, the North Fork. Pools were the preferred habitat for adult spring chinook in both subbasins; however, riffles were used more in the North Fork, the coldest subbasin. This study identified the problems and also the benefits associated with stream temperature patchiness, or discontinuity, both in currently disturbed and in recovering riverine ecosystems. Connectivity among system components in aquatic ecosystems is generally considered necessary for maintaining long-term ecological health. However, it is heterogeneity in the landscape/hydrogeologic template that creates refuge patches in disturbed stream ecosystems, such as those in the John Day River basin. Our observations of thermal refugia occurring at multiple spatial scales, particularly in the Middle Fork John Day River, indicate that, although discontinuity may be an ecological warning sign, refuge patches in streams should also be viewed as expressions of restoration potential because they are functioning remnants of a once continuous, intact hydrologic system. / Graduation date: 1997

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 species Oncorhynchys mykiss (commonly known as steelhead and rainbow trout), I found that sex plays a strong role in whether an individual adopts an anadromous or resident life history. I observed a higher frequency of females adopting the anadromous tactic throughout the species range, and I attributed this to the relationship between body size and reproductive success in females that is not present in males. I did not observe differences in female bias along gradients of latitude or migration distance, and I hypothesize that while the frequency of tactics among populations may change along these gradients, either the change is equal between males and females, or an interaction of latitude and migration distance may control changes. I did not observe a corresponding male bias in the one resident population I sampled, and suggest that this is the result of a high frequency of residents in that population. I propose that sex ratios could be a valuable metric for measuring frequency of life-history tactics in populations and could facilitate the investigation into the controls of life-history tactics across broad scales. / Graduation date: 2013

This study was an investigation of lotic macroinvertebrate distribution in northeastern Oregon at two different spatial and biological scales. Examination of assemblages at a limited spatial scale revealed relationships with natural and disturbance gradients and led to questions about distribution of a population at broader spatial scales. In a 16 kilometer section of the North Fork John Day River, I examined the relationship of invertebrate assemblages to habitat and fine sediment deposition. This river section was subjected to sediment inputs resulting from several years of floodplain mine-tailing leveling, and erosion and tributary channel scouring following a forest fire. Invertebrate assemblages differed between habitat types. The proportion of sediment tolerant invertebrates, especially oligochaete worms, increased with higher amounts of deposited fine sediment, but total invertebrate abundance was not related to deposited sediment. The response of sediment tolerant invertebrates appeared to reflect cumulative impacts from multiple input points and downstream transport of sediment and cumulative and/or increasing impacts over the two years of sampling. In studying assemblages in the North Fork, I noticed an unusual abundance of the caddisfly, Lopidostoma pluviale (Milne). In a more spatially extensive examination of a population, I investigated distribution of this caddisfly in the Blue Mountain region of northeastern Oregon. L. pluviale was more common and/or abundant further downstream than would be expected for a shredding feeder based on the River Continuum Concept (Vannote, et al., 1980). Through gut content analyses, I demonstrated that this species is much more of a generalist feeder than its designation as a shredder would imply. Consequently, its distribution is not limited to headwaters where allochthonous food resources are abundant. I hypothesize that non-food environmental factors may be more important in determining the distribution of this species. Results of this research indicate that assemblage studies can reveal interesting relationships with environmental conditions. In addition, paying attention to unusual distributions of taxa in assemblage studies can lead to further studies that can improve our understanding of the biology and ecology of species. / Graduation date: 2004

The growing demand for water in the arid regions of the West increases the need for optimal allocation of water among competing uses. An efficient allocation of water between instream and out-of-stream uses has been impeded by institutional constraints and the scarcity of information regarding instream flow benefits. The objectives of this thesis were to provide preliminary economic data on the value of instream water in "producing" recreational fishing and to examine the effect of forestry, agriculture, and livestock practices on temporal streamflow patterns and anadromous fish production. The steelhead trout (Salmo gairdneri) sport fishery within the John Day River basin in north-central Oregon provided the setting for this research. The interdisciplinary methodology employed in estimating the marginal value of water with respect to steelhead production consisted of two tasks. The first task involved valuing a marginal change in the quality of the steelhead recreational fishery. The contingent valuation method (CVM) was selected for this purpose. Both open- and closed-ended willingness-to-pay (WTP) questions were included in a questionnaire administered to John Day River steelhead anglers during the 1986/87 steelhead fishing season. Survey data were analyzed to arrive at individual and aggregate bid functions relating WTP to expected angling success rates. Results indicate that, under current conditions, the average angler is willing to pay approximately $7.20 to catch an additional steelhead. The second task of the instream water valuation methodology was directed at deriving a streamflow/steelhead production relationship. By including variables influencing steelhead production in a Ricker stock-recruitment model, it was possible to develop a model which could be estimated using linear regression techniques. Some difficulty arose, however, with interpretation of the model due to the unavailability of cohort escapement data and the subsequent use of standing crop data. While possibly masking the true magnitude of streamflow's effect on fish production, this drawback was not deemed limiting within the general context of the interdisciplinary methodology. Results of the biological model conformed to a priori expectations. Increases in summer and winter streamflows led to increased steelhead survival, whereas higher spring flows increased mortality levels. Other results indicate that the John Day Dam was responsible for a 31.5 percent decline in the population index for the 1969-1983 period. Combining the economic and biological results into one equation yielded an estimate of the marginal value of summer instream water in "producing" recreational steelhead angling. Similar equations were developed for winter and spring flows. The marginal value of water in producing recreational steelhead fishing within the John Day basin was estimated at $0.56 per acre-foot for summer flows, $0.046 for winter flows, and -$0.075 for spring flows. By including out-of-basin benefits, these values increased to $2.26, $0.19, and -$0.30, respectively. In comparison, water's value in irrigation within the John Day basin has been estimated at between $10 to $24 per acre-foot. However, nonuse values of steelhead, as well as the increased production of other fish species (such as spring chinook salmon) were not included in the instream water values. In addition, no attempt was made at valuing instream water's contribution to boating, camping, or other benefit-producing activities. A secondary objective of this thesis was to briefly examine the possible benefits accruing to other instream and out-of-stream users due to an alteration in streamflow patterns. In addition, the impact of activities by other resource users -- namely forestry, agriculture, and livestock production --on anadromous fish production was reviewed. Improper management practices by these activities can negatively impact the aquatic and riparian ecosystems. While no firm conclusions were drawn, it appears the quality of these ecosystems, as opposed to the amount of streamflow, has the largest marginal impact on anadromous fish populations. / Graduation date: 1988