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Christy Leppanen

Research Assistant Professor

Research Interest

Invasion biology, environmental toxicology, sustainability


Ph.D. Biological Sciences, University of Maine

M.S. Biology, University of Memphis

B.S. Biology and Chemistry, University of Memphis


I am interested in the impacts and management of disturbance in ecological systems. Disturbance as a result of biological (e.g., invasive species or disease), physical (e.g., tree removal), or chemical (e.g., pesticide drift) perturbations may lead to impacts that we determine require management. The complexity of ecological systems, unfortunately, means that management often does not incorporate comprehensive information about mechanisms underlying impacts or proposed solutions. Because understanding these mechanisms is essential to focus successful research and management, I am interested in learning how to better identify and determine how direct interactions (e.g., competition, mutualism, and amensalism) and indirect interactions (e.g., exploitative competition, keystone predation, and habitat facilitation) influence the effects of disturbance. I am also interested in how variability in these interactions in undisturbed systems translates to disturbed systems (and vice versa), particularly when considering the effects of climate change. For example, interactions, as well as variability in those interactions, in the native range of a species may differ markedly in its introduced range, particularly when both populations are differentially subjected to variable effects of climate change. Such variability has implications for managing these populations when knowledge is transferred from one system to another.

I am studying the impacts and management of a plant-feeding insect, the hemlock woolly adelgid (Adelges tsugae, Hemiptera: Adelgidae) where it is native and where it has been introduced. Transplanted from its native range in Japan to a very different system in the eastern United States, this insect has heavily impacted eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) populations in its new range. Identifying and comparing important interactions and variability in those interactions in communities in the adelgid’s native and introduced ranges may hold promise for mitigating the effects of this devastating pest.

Professional Service

Courses Taught:

  • EEB 461: Environmental Toxicology
  • EEB 461: Invasion Biology

Awards and Recognitions

Selected awards and appointments

  • Foreword Reviews’ INDIEFAB 2014 Book of the Year Award Bronze Winner for Horror, Finalist for Humor and Science Fiction (2015), and Five-Star Review (2014), Bulletin of ZOMBIE Research, Foreword Clarion Reviews, Traverse City, MI
  • Kirkus Star and Best Books of 2014 (2014), Bulletin of ZOMBIE Research, Kirkus Reviews, Austin,TX
  • Scholar in Residence (2014), Helen R. Whiteley Center, University of Washington, Friday Harbor Laboratories, Friday Harbor, WA
  • National Geographic Explorer (2007-2008), National Geographic Society, Conservation Trust, New York, NY
  • Board of Directors and Grants Chair (2005-2008), Friends of Midway Atoll National Wildlife Refuge, Milwaukie, OR
  • National Science Foundation GK12 Teaching Fellow (2005-2006), University of Maine, Orono, ME


Representative publications and presentations
(Former surname: Finlayson)

  • Henning J, Leppanen C, Bush J, Sheldon K, Gotelli N, Gravel D, Strauss S, Simberloff D, Wilson EO (In press) A pioneering adventure becomes an ecological classic.  Bulletin of the Ecological Society of America.
  • Leppanen C, Simberloff D (2017) Implications of early production in an invasive forest pest.  Agricultural and Forest Entomology 19: 217-224.
  • Welch JN, Leppanen C (2017) The threat of invasive species to bats: A review.  Mammal Review 47: 277-290.  DOI: 10.1111/mam.12099.
  • Rogers TJ, Simberloff D, Leppanen C, Brown V, Cregger MA (2017) Deciphering how insect susceptibility alters stem microbial communities across hemlock tree species. Department of Energy Science Undergraduate Laboratory Internship Report, Oak Ridge National Laboratory, Oak Ridge, TN.
  • Leppanen C, Simberloff D (2016) Considering small potatoes: Can cumulative minor interactions in different locations explain variable impacts of an invasive species? Proceedings of the 27th USDA Interagency Research Forum on Invasive Species, 12-15 January 2016, Annapolis, MD.
  • Leppanen C (2016) Zombi Encephalitis-associated increases in the germination and growth of four thistle species (Family: Asteraceae). Proceedings of the 27th USDA Interagency Research Forum on Invasive Species, 12-15 January 2016, Annapolis, MD.
  • Simberloff D, Leppanen C (2015) Coccinellids, imidacloprid, Lecanicillium, and the hemlock woolly adelgid keeps rolling along. Entomological Society of America 63rd Annual Meeting, Minneapolis, MN.
  • Leppanen CJ (2014) Bulletin of ZOMBIE Research: Volume 1. CreateSpace Independent Publishing Platform, Charleston, SC. ISBN: 978-1-4995-7675-7. 184 pages.
  • Leppanen CJ (2012) A review of fortuitous and intentional biological control releases on Guam. Entomological Society of America 60th Annual Meeting, Knoxville, TN.
  • Leppanen C, Alyokhin A, Gross S (2012) Competition for aphid prey between different lady beetle species in a laboratory arena. Psyche. Article ID 890327, doi:10.1155/2012/890327, 9 pages.
  • Alyokhin A, Leppanen C (2012) Ecological interactions between non-native and native lady beetles in Maine, the United States. XXIV International Congress of Entomology, Daegu, Korea.
  • Finlayson (Leppanen) C, Alyokhin A, Gross S, Porter E (2010) Differential consumption of four aphid species by four lady beetle species. Journal of Insect Science 10:31,, 10 pages.
  • Finlayson (Leppanen) CJ, Alyokhin AV, Porter EW (2009) Interactions of native and non-native lady beetle species with aphid-tending ants in laboratory arenas. Environmental Entomology 38: 836-845.
  • Finlayson (Leppanen) CJ, Landry KM, Alyokhin AV (2008) Abundance of native and non-native lady beetles in different habitats in Maine. Annals of the Entomological Society of America 101: 1078-1087.
  • Finlayson (Leppanen) CJ (2008) Excrement eaters: Relationships between invasive ants, treehoppers, and the invasive plant, golden crownbeard, on Midway Atoll. Midway Atoll National Wildlife Refuge, Midway Atoll, Northwestern Hawaiian Islands.
  • Finlayson (Leppanen) C, Alyokhin A (2007) Biological invasions: A review (Synthesis Document). Network of Conservation Educators and Practitioners, Center for Biodiversity & Conservation, American Museum of Natural History, New York, NY. 42 pages.
  • Alyokhin A, Finlayson (Leppanen) C (2007) Biological invasions: A review (Exercise and Presentation Modules). Network of Conservation Educators and Practitioners, Center for Biodiversity & Conservation, American Museum of Natural History, New York, NY. 9 pages, 42 slides with notes.
  • Finlayson (Leppanen) C (2007) Teaching Lesson: Management of an invasive plant, golden crownbeard (Verbesina encelioides), on Midway Atoll – YOU DECIDE. Midway Atoll National Wildlife Refuge, United States Fish and Wildlife Service, Washington DC. 11 pages.
  • Finlayson (Leppanen) C, Carrier C, Brown S, Libby A* (2006) Considering biocontrol and biological invasions: An experimental unit for primary and secondary school classrooms. Neobiota, 4th European Conference on Biological Invasions, Vienna, Austria. *Collaboration with NSF GK12 teachers and their students.
  • Finlayson (Leppanen) C (2006) Eight lessons about lady beetles: Using lady beetles to learn about insects, pest ecology, biocontrol, and biological invasions. National Science Foundation GK12 Teaching Fellows Program, University of Maine, Orono, ME. 55 pages.
  • Leppanen CJ, Maier KJ (1998) An inexpensive and efficient modular water-renewal system for bulk sediment toxicity testing. Environmental Toxicology and Chemistry 17: 969-971.
  • Leppanen CJ, Blanner P, Allan RS, Benson WH, Maier KJ (1998) Using a triad approach in the assessment of hazardous waste site leaching from a Superfund site to an adjacent stream. Environmental Toxicology and Chemistry 17: 2106-2113.

Contact Information

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