Arif Jan (co-advisor Dr. Ivan Arismendi)
Dissertation topic: Multiscale ecological niche models to predict the distribution of biological invasions in riverscapes.
I am interested in the distribution of invasive fish species in both geographic and environmental (niche) spaces. My research project focuses on developing ecological niche models in the native areas of invasive salmonids and carps and transfer those models cross-continentally to predict the distribution of their invasion in the Indus Basin, east coast of North America and Patagonia. I use different R packages to model the climatic niches of invasive fishes in their native and introduced ecosystems and generate hypotheses about any shift in their realized niches. I also use Geographic Information Systems (GIS) to characterize stream network from high resolution digital elevation models (DEM) which allows to combine vector and raster-based stream variables to develop more robust ecological niche models. I am also interested in the effect of climatic change on niche shift and geographic distribution of invasive fishes.
Logan Breshears (co-advisor Dr. Jonathan Armstrong)
Thesis Topic: Characterizing thermal refuge usage in the Columbia River, and “Overshoot” migration behavior for John Day River adult summer steelhead.
Logan is an ODFW biologist interested in studying the environmental factors driving population dynamics of wild summer steelhead in the John Day Basin. It is estimated that 60% of adult steelhead destined for the John Day River overshoot the mouth of the John Day River upon their initial upstream arrival, and continue migrating up the Columbia River, getting detected at McNary Dam 119km upstream. A proportion of these fish later return to the John Day River to spawn the following spring. Logan will be using a combination of acoustic telemetry and PIT tags to characterize and quantify individual pathways of John Day origin adult summer steelhead throughout the Columbia River Basin. Monitoring areas of emphasis include the John Day River confluence with the Columbia River, and thermal refuge areas downstream of John Day Dam.
Thesis Topic: An Investigation of Stage 0 Restoration in California and Oregon
My interests have been shaped by my experiences living near the southern end of coho salmon’s range in Northern California. Many populations are of salmon and steelhead face long odds to recover to meaningful levels in California. Spending limited conservation dollars effectively and efficiently is a major goal of funders and restoration practitioners. My work looks at the efficacy of an emerging type of floodplain restoration as a potential approach to increase the scale of restoration projects while restoring ecological processes.
Charlie is now the North Coast Coordinator for Trout Unlimited in Coastal Northern California.
Thesis Topic: Growth and survival of Alternative life history pathways of Juvenile Chinook Salmon in the upper John Day Basin
Recent studies indicate in the Upper John Day Basin greater numbers of sub-yearling Chinook salmon migrate early in their first summer of life to downstream nursery habitats than those that remain in the upper natal reaches. This early migrants seem to make up a majority of smolting yearlings in many years. There are many advantages for this life history to be favored by Chinook salmon in this river but it is the diversity of life histories what contributes to the stability and resilience of the population. Michael is investigating whether sub-yearling Chinook salmon that migrate early make up the largest proportion of their cohort. He is also characterizing what habitats these fish prefer and which ones offer better growth and survival conditions.