B.S., University of Idaho
M.S., Washington State University
Ph.D., Washington State University
Joined Westfield State University in 2008


Freshwater ecology
Conservation biology

Teaching Philosophy:

I believe learning should be a perpetual endeavor in life that is often achieved through multiple processes such as visual, auditory, repetitive, and hands-on approaches. Each student may possess a mosaic of learning styles and have the potential to excel when given the right tools and opportunities. In my classes, I try to integrate different teaching styles in order to address the variety of learning methods that exist and to generate sincere interest among students regarding the diverse topics of biology. I believe teaching is a dynamic process that requires professors to be vigilant in adjusting and applying new methodologies to meet the needs of our students in varying courses and disciplines.

Courses Dr. Christensen Teaches:

BIOL 219 Aquatic Biology, BIOL 202 Conservation Biology, BIOL 377 Research Experience in Stream Ecology and Restoration, BIOL 106 Biology Today, BIOL/ENVS 233 Environmental Legislation, ENVS 220 Surface and Groundwater Hydrology, BIOL 540 Environmental Science


Course Work and Research Interests

Students spend a lot of time in the field collecting data on real-world projects in my courses; Aquatic Biology, Conservation Biology, Hydrology and Stream Ecology and Restoration. This gives students an opportunity to not only gain real-world experience but to participate in ongoing ecological restoration projects such as dam removal, culvert replacement monitoring, lake and pond monitoring and educational outreach. Numerous students have conducted independent research in these same areas and have presented their results at WSU, regional and national conferences. Below are a few images from my courses and student research projects. 

3 images of old dam removal on a local waterway

The above images depict the Kinne Brook Dam removal that began in 2013. Students in my Conservation Biology and Stream Ecology and Restoration courses as well as those conducting independent research have been monitoring the impact of the dam and it's removal each year since 2012. Students measured variables such as stream morphology, substrate variability, macroinvertebrate diversity and fish community structure from before and after the dam removal. 

4 images of WSU students conducting research on a local waterway

In my classes and research, students have used methodologies such as electrofishing, water quality sondes, surveying, Wolman Pebble Counts, culvert fish passability indices, macroinvertebrate collections, riparian measures, habitat suitability index modeling, stable isotope analysis, zooplankton collections, Secchi measures, stream discharge estimates and software such as Image J, SPSS, MetashapePro, IsoSource and Oliver; Mass GIS.

Old dam removal on local waterway

Sediment shifts and bank instability after the dam was removed was a major concern. Although fine sediments flushed downstream quickly, bank instability remained a problem for many years after the dam was removed. 

Old dam removal on local waterway

The images above depict students using electrofishing to sample the fish community of a local pond in my Aquatic Biology course. The figure represents length v. nitrogen 15 and carbon 13 ratios in chain pickerel sampled from the pond. The results suggested an increasing diet of larger invertebrates and fish and an increase in trophic position as the chain pickerel grew.

two images of WSU students presenting research

Students presenting their work at our biannual research symposium.

Image featuring a series of local freshwater fish

The fishes above are commonly sampled on our Aquatic Biology lake electrofishing field trips. Native (N), Introduced (I).


Journal publications:

Christensen, D.R. and B.C. Moore. 2007. Differential prey selectivity of largemouth bass functional feeding groups in Twin Lakes, Washington. Lake and Reservoir Management 23:39-48.

Christensen, D.R. and B.C. Moore. 2008. Diet composition and overlap in a mixed warm- and coldwater fish community. Journal of Freshwater Ecology 23:195-204.

Christensen, D.R. and B.C. Moore. 2009. Using stable isotopes and a multiple source mixing model to evaluate fish dietary niches in a mesotrophic lake. Lake and Reservoir Management 25:167-175.

Moore, B.C. and D.R. Christensen. 2009. Newman Lake restoration: A case study. Part 1. Chemical and biological responses to phosphorus control. Lake and Reservoir Management 25:337-350.

Moore, B.C., D.R. Christensen, and A.C. Richter. 2009. Newman Lake restoration: A case study. Part II. Microfloc alum injection. Lake and Reservoir Management 25:351-363.

Christensen, D.R. and B.C. Moore. 2010. Largemouth bass consumption demand of hatchery rainbow trout in two Washington lakes. Lake and Reservoir Management 26:200-211.

Christensen, D.R. and A. LaRoche. 2012. Using stable isotopes of carbon and nitrogen to evaluate trophic interactions in aquatic environments. Bioscene 38:22-27.

Moore BC, Cross BK, Clegg EM, Lanouette BP, Biggs M, Skinner M, Preece E, Child A, Gantzer P, Shallenberger E, Christensen DR, Nine B, 2014. Hypolimnetic oxygenation in Twin Lakes, WA. Part 1: Distribution and movement of trout. Lake and Reservoir Management 30:226-239.

Christensen, D.R. 2016. A simple approach to collecting useful wildlife data using remote camera-traps in undergraduate biology courses. Bioscene 42:25-31.

Magazine publications:

Beutel, M., Moore, B.C., Christensen, D.R., Ganzer, P., Shallenberger, E. 2010. Ease the squeeze in Twin Lakes, WA - The Colville Confederated Tribes work to enhance a trout fishery and improve water quality in reservation lakes. Lakeline-Winter:31-38.

Christensen, D.R. 2011. Drift Away: Dead-drifting streamer flies. American Angler. September/October: 42-45. This article was written as an enjoyable breather from the regular scientific approach. It was good to simplify and reconnect with my initial and fundamental interest in aquatic biology; fishing.

Christensen, D.R. 2013. Pike Congregations. American Angler. January/February: 20-21. This was another article I submitted for fun as a way to stay connected with my fundamental interest in fish and their habitats.

Student publications:

Christensen, D.R. and A. LaRoche. 2012. Using stable isotopes of carbon and nitrogen to evaluate trophic interactions in aquatic environments. Bioscene 38:22-27.

Favata, C.A., Christensen, D.R., Thompson, R., McKeown, K.A., and J. Hanselman. 2015. Evaluation of a modified habitat suitability index model for eastern brook trout: Implications for efficient habitat assessment. Journal of Student Research 4:90-98.