ryan harrigan

Ryan Harrigan Ph.D.

Assistant Adjunct Professor, IoES; Assistant Researcher

Center for Tropical Research

Center for Tropical Research
UCLA Institute of the Environment and Sustainability
La Kretz Hall, Suite 300
Los Angeles, CA 90095-1496

(203) 804-9505

Research Interests

My main research interests include the evolutionary biology and ecology of species and species complexes. Separate and yet not mutually exclusive evolutionary forces often contribute to the complex phylogenetic relationships we are witness to across the globe. These include events such as hybridization and introgression between closely related taxa, past and current speciation events, and incomplete lineage sorting. My research focuses on these biological phenomena, and how they help to shape the current patterns and genetic relationships among organisms. Particularly interesting to me are cases where additional anthropogenic forces are likely contributing to already complex natural processes. Such is the case in North American waterfowl, for instance, where a commercially and recreationally valuable species complex has been subjected to both natural and artificial influences, resulting in the patterns of phylogeography and distribution we see today. My current work is focused on how anthropogenic stressors have affected the spread of recently introduced, multi-host pathogens, and how migrant bird populations have been affected by such introductions.

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Alternative Energy and Biodiversity

A U.S. Department of Energy Funded Project to Understand the Demographic Impacts of Solar Energy Sites on Migratory Bird Populations Increased solar energy production is a critical element of efforts…

biodiversity atlas

Biodiversity Atlas

Southern California harbors some of the highest levels of biodiversity on the continent, yet is also home to millions of humans that compete for wildlife space and resources. In order to best balance these often competing components, researchers at the Center for Tropical Research are helping to construct a Los Angeles Biodiversity Atlas.



The Center for Tropical Research is investigating what may be the environmental drivers of infectious diseases, and what might trigger outbreaks during particular times or conditions. In collaboration with Dr. Rick Schoenberg, chair of the the Department of Statistics at UCLA, our team is using novel models to understand ebola outbreaks.

west nile virus

West Nile Virus

West Nile virus (WNV) has spread rapidly in North America, threatening wildlife and posing serious health risks to humans. In order to better understand how the distribution of WNV will further impact populations, we model the incidence of WNV infections under current conditions, and use these to predict where the disease may occur in the future.


Predicting bird song from space

Smith, T. B.; Harrigan, R. J.; Kirschel, A. N.; Buermann, W.; Saatchi, S.; Blumstein, D. T.; de Kort, S. R.; Slabbekoorn, H.

Published Work | 2013 | Evolutionary Applications 6(6), 865–874