Graham, Jessica

• Postdoctoral Researcher, Behavioral Ecology Team, Centre National de la Recherche Scientifique 

• Ph.D., Environmental & Conservation Sciences, North Dakota State University

•  B.S., Natural Resource Sciences, Washington State University

The American dipper (Cinclus mexicanus) is North America’s only truly aquatic songbird, relying on fast-moving, clear, cold streams for food and habitat. They serve as bioindicators of water quality and pollution in freshwater ecosystems. However, relative population size in many coastal populations appears to be declining, the cause of which is unknown. In the Black Hills of South Dakota, the American dipper population has been declining since the 1980s, facing challenges such as low reproductive rates, and ongoing threats from urbanization, water pollution, and invasive species. Classified as a species of greatest conservation need, South Dakota Game, Fish, and Parks is interested in identifying the specific factors causing population decline. Although little research is currently being conducted on American dippers in North America, gaining a better understanding of the factors driving the decline in Black Hills dippers could provide valuable insights into the challenges faced by other dipper populations.

I am interested in studying how changes in habitat characteristics affect genome integrity and gene expression of Black Hills dippers, with the goal of better understanding the factors driving population decline. To achieve this, I plan to compare Black Hills dippers with a reference population of dippers in the Bighorn Mountains, whose population is currently expanding. My research will involve field work in SD and WY to assess habitat characteristics of nest sites and collect samples from Black Hills and Bighorn Mountain dippers to measure their effects on telomere length and differential gene expression between populations. Telomeres, the repetitive, non- coding DNA sequences that form protective caps at the ends of chromosomes, enhance genome integrity. Lifespan of a cell can be limited by telomere length as they shorten during normal cell division. Telomeres also shorten in response to environmental stressors. Telomere length and loss rate have been shown to be predictive of longevity in many species. Habitat characteristics may be resulting in shorter telomeres, which may subsequently shorten lifespan. Using differential gene expression, I hope to identify physiological pathways that are being negatively affected by habitat degradation, and their health consequences. As apex predators in freshwater ecosystems, dippers are crucial bioindicators of water quality and pollution. While most dipper populations in landlocked states appear to be thriving, it is concerning that coastal populations seem to be in decline. Understanding the causes of population decline in the dippers of the Black Hills could have broader implications for stream biodiversity, water quality, and ultimately, human health in Western North America.