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Dr. Aaron B. Shiels


        Dr. Aaron B. Shiels        
Research Biologist

NWRC Research Project: Development of Methods to Control Rodent Populations and Damage

Current Research 

Dr. Aaron Shiels is a research biologist at the National Wildlife Research Center, Fort Collins, Colorado.  His current research is focused on developing and testing methods to reduce invasive and native rodent damage with both lethal and nonlethal approaches in island and continental ecosystems.

Research Interests

Rodents, Ecology and Management, Conservation Biology, Disturbance, Global Change, Human-Wildlife Interactions, Wildlife Damage Management, Plant-Animal Interactions, Invasive Species


  • Ph.D., University of Hawaii at Manoa, Botany, “Ecology and impacts of introduced rodents (Rattus spp. and Mus musculus) in the Hawaiian Islands”
  • M.S., University of Nevada, Las Vegas, Biology, “Bird perches and soil amendments as revegetation techniques for landslides in Puerto Rico”
  • B.S., University of Denver, Environmental Science, “Soil nutrient differences between Pinus aristata and Picea engelmannii krummholz in alpine-tundra, Goliath Peak, Colorado”

Contact Information:

  • Address: NWRC
                   4101 LaPorte Avenue
                   Fort Collins, CO  80521
  • Telephone: 970-266-6324
  • E-mail:

Recent Publications


Avery, M.L. and A.B. Shiels. 2018. Monk and rose-ringed parakeets. pgs. 333-357. In: W.C. Pitt, J.C. Beasley, and G.W Witmer, editors. Ecology and Management of terrestrial vertebrate invasive species in the United States. CRC Press, Boca Raton, FL. 403 pp.

Beard, K.H., S.A. Johnson, and A.B. Shields. 2018. Frogs (Coqui frogs, greenhouse frogs, Cuban tree frogs, and cane toads). pgs. 163-192. In: W.C. Pitt, J.C. Beasley, and G.W Witmer, editors. Ecology and Management of terrestrial vertebrate invasive species in the United States. CRC Press, Boca Raton, FL. 403 pp.

Engeman, R.M., A.B. Shiels, and C.S. Clark. 2018. Objectives and integrated approaches for the control of brown tree snakes: An updated overview. Journal of Environmental Management 219:115-124. doi: 10.1016/j.jenvman.2018.04.092

Engeman, R.M., M.L. Avery, A.B. Shiels, A.R. Berentsen, K.C. VerCauteren, R.T. Sugihara, A.G. Duffiney, C.S. Clark, J.D. Eisemann. 2018. Diverse examples from managing invasive vertebrate species on inhabited islands of the United States. Australasian Journal of Environmental Management 25(1):43-61. doi: 10.1080/14486563.2017.1393466 

Shiels, A.B., and G.E. Ramirez de Arellano. 2018. Invasive rats (Rattus sp.), but not always mice (Mus musculus), are ubiquitous at all elevations and habitats within the Caribbean National Forest, Puerto Rico. Caribbean Naturalist 48:1-14.

Shiels, A.B., W.P. Bukoski, and S.R. Siers. 2017. Diets of Kauai's invasive rose-ringed parakeet (Psittacula krameri): evidence of seed predation and dispersal in a human-altered landscape. Biological Invasions 20:1449-1457. doi: 10.1007/s10530-017-1636-5

Witmer, G.W. and A.B. Shiels. 2018. Ecology, impacts, and management of invasive rodents in the United States. pgs. 193-219. In: W.C. Pitt, J.C. Beasley, and G.W Witmer, editors. Ecology and Management of terrestrial vertebrate invasive species in the United States. CRC Press, Boca Raton, FL. 403 pp.


Duron, Q., A.B. Shiels, and E. Vidal. 2017. Control of invasive rats on islands and priorities for future action. Conservation Biology 31(4):761-771. doi: 10.1111/cobi.12885

Shiels, A.B., A.C. Medeiros, and E.I. von Allmen. 2017. Shifts in an invasive rodent community favoring Black rats (Rattus rattus) following restoration of native forest. Restoration Ecology. doi: 10.1111/rec.12494

Shiels, A.B., W.P. Haines, K.J. Swinnerton, S. Silander, C. Figuerola-Hernandez, D. Will, J.G. Garcia-Cancel, and C.W. Torres-Santana. 2017. Sudden appearance and population outbreak of Eunica monima (Lepidoptera: Nymphalidae) on Desecheo Island, Puerto Rico. Florida Entomologist 100(1):176-179. doi: 10.1653/024.100.0127

Smith, R.L., K.H. Beard, and A.B. Shiels. 2017. Different prey resources suggest little competition between non-native frogs and insectivorous birds despite isotopic niche overlap. Biological Invasions 19(3):1001-1013. doi: 10.1007/s10530-016-1333-9


Shiels, A.B. and G. González. 2015. Tropical forest responses to large-scale experiments. BioScience 65(9):839.   doi:10.1093/biosci/biv126

Shiels, A.B., G. González, D.J. Lodge, M.R. Willig, and J.K. Zimmerman. 2015. Cascading effects of canopy opening and debris deposition from a large-scale hurricane experiment in a tropical rain forest. Bioscience 65(9):871-881.  doi: 10.1093/biosci/biv111

Shiels, A.B. and D.R. Drake. 2015. Barriers to seed and seedling survival of once-common Hawaiian palms: The role of invasive rats and ungulates.  AoB Plants 7(1):plv057.  doi: 10.1093/aobpla/plv057

Jarvi, S.I., W.C. Pitt, M.E. Farias, L. Shiels, M.G. Severino, K.M. Howe, S.H. Jacquier, A.B. Shiels, K.K. Amano, B.C. Luiz, D.E. Maher, M.L. Allison, Z.C. Holtquist, and N.T. Sheibelhut. 2015. Detection of Angiostrongylus cantonensis in the blood and peripheral tissues of wild Hawaiian rats (Rattus rattus) by a quantitative PCR (qPCR) assay. PLoS One 10(4):e0123064. doi: 10.1371/journal.pone.0123064

Berentsen, A.R., S. Vogt, A.N. Guzman, D.S. Vice, W.C. Pitt, A.B. Shiels, and  T.R. Spraker. 2015. Capillaria hepatica infection in black rats (Rattus rattus) on Diego Garcia, British Indian Ocean Territory. Journal of Veterinary Diagnostic Investigation 27(2):241-244.  doi: 10.1177/1040638715573298

Pitt, W.C., A.R. Berentsen, A.B. Shiels, S.F. Volker, J.D. Eisemann, A. Wegmann,  and G. Howald.  2015. Non-target species mortality and the measurement of brodifacoum rodenticide residues after a rat (Rattus rattus) eradication on Palmyra Atoll, tropical Pacific. Biological Conservation 185:36-46.  doi: 10.1016/j.biocon.2015.01.008.


Shiels, A.B., and W.C. Pitt. 2014. A review of invasive rodent (Rattus spp. and Mus musculus) diets on Pacific Islands. Proceedings of the 26th Vertebrate Pest Conference 26:161-165.

Zimmerman, J.K., J.A. Hogan, A.B. Shiels, J.E. Bithorn, S.M. Carmona, and N. Brokaw. 2014. Seven-year responses of trees to experimental hurricane effects in a tropical rainforest, Puerto Rico. Forest Ecology and Management 332:64-74.  doi: 10.1016/j.foreco.2014.02.029

Klawinski, P.D., B. Dalton, and A.B. Shiels. 2014. Coqui frog populations are negatively affected by canopy opening but not detritus deposition following an experimental hurricane in a tropical rainforest. Forest Ecology and Management 332:118-123. doi: 10.1016/jforeco.2014.02.010.

Sharpe, J.M. and A.B. Shiels. 2014. Understory fern community structure, growth and spore production responses to a large-scale hurricane experiment in a Puerto Rico rainforest. Forest Ecology and Management 332:75-86.  doi: 10.1016/j.foreco.2014.01.023.

Shiels, A.B., G. Gonzalez. 2014. Understanding the key mechanisms of tropical forest responses to canopy loss and biomass deposition from experimental hurricane effects. Forest Ecology and Management.  doi: 10.1016/jforeco.2014.04.024.

Shiels, A.B., G. Gonzalez, and M.R. Willig. 2014. Responses to canopy loss and debris deposition in a tropical forest ecosystem: Synthesis from an experimental manipulation simulating effects of hurricane disturbance. Forest Ecology and Management.  doi: 10.1016/j.foreco.2014.08.005.

Shiels, A.B., M.K. Ennis, and L. Shiels. 2014. Trait-based plant mortality and preference for native versus non-native seedlings by invasive slug and snail herbivores in Hawaii. Biological Invasions 16(9): 1929-1940. doi: 10.1007/s10530-013-0636-3.

Shiels, A.B., W.C. Pitt, R.T. Sugihara, and G.W. Witmer. 2014. Biology and impacts of Pacific Island invasive species. 11. The Black Rat, Rattus rattus (Rodentia: Muridae). Pacific Science 68(2): 145-184. doi: 10.2984/68.2.1.


Walker, L.R., and A.B. Shiels. 2013. Landslide Ecology. Cambridge University Press, Cambridge, U.K.   

Shiels, A.B., and L.R. Walker. 2013. Landslides cause spatial and temporal gradients at multiple scales in the Luquillo Mountains of Puerto Rico. In: G. González, M. Willig, and R. Waide, editors. Ecological Gradient Analyses in a Tropical Landscape. Ecological Bulletins. Blackwell Science, Oxford, U.K. 211-222.  

Shiels, A.B., C.A. Flores, A. Khamsing, P.D. Krushelnycky, S.M. Mosher, and D.R. Drake. 2013. Dietary niche differentiation among three species of invasive rodents (Rattus rattus, R. exulans, Mus musculus). Biological Invasions 15:1037-1048.  doi: 10.1007/s10530-012-0348-0.

Walker, L.R., A.B. Shiels, P.J. Bellingham, A.D. Sparrow, N. Fetcher, F.H. Landau, and D.J. Lodge. 2013. Changes in abiotic influences on seed plants and ferns during 18 years of primary succession on Puerto Rican landslides. Journal of Ecology 101:650-661. doi: 10.1111/1365-2745.12071

Pender, R.J., A.B. Shiels, L. Bialic-Murphy, and S.M. Mosher. 2013. Large-scale rodent control reduces pre- and post-dispersal seed predation of the endangered Hawaiian lobeliad, Cyanea superba subsp. superba (Campanulaceae). Biological Invasions 15:213-223.  doi: 10.1007/s10530-012-0280-3.


Shiels, A.B., and D.R. Drake. 2011. Are introduced rats (Rattus rattus) both seed predators and dispersers in Hawaii? Biological Invasions 13: 883-894.  

Shiels, A.B. 2011. Frugivory by introduced black rats (Rattus rattus) promotes dispersal of invasive plant seeds. Biological Invasions 13: 781-792.


Shiels, A.B., J.K. Zimmerman, D.C. Garcia-Montiel, I. Jonckheere, J. Holm, D. Horton, and N. Brokaw. 2010. Plant responses to simulated hurricane impacts in a subtropical wet forest, Puerto Rico. Journal of Ecology 98: 659-673.

Walker, L.R., F. Landau, E. Velázquez, A.B. Shiels, and A.D. Sparrow. 2010. Early successional woody plants facilitate and ferns inhibit forest development on Puerto Rican landslides. Journal of Ecology 98: 625-635.

Richardson, B.A., M.J. Richardson, G. González, A.B. Shiels, and D.S. Srivastava. 2010. A canopy trimming experiment in Puerto Rico: The response of litter invertebrate communities to canopy loss and debris deposition in a tropical forest subject to hurricanes. Ecosystems 11: 286-301.


Restrepo, C., L.R. Walker, A.B. Shiels, R. Bussman, L. Claessens, S. Fisch, P. Lozano, G. Negi, L. Paolini, G. Poveda, C. Ramos-Scharrón, M. Richter, and E. Velázquez. 2009. Landsliding and its multi-scale influences on mountainscapes. BioScience 59: 685-698.

Walker, L.R., E. Velázquez, and A.B. Shiels. 2009. Applying lessons from ecological succession to the restoration of landslides. Plant and Soil 324: 157-168.

Meyer, W.M., and A.B. Shiels. 2009. Black rat (Rattus rattus) predation on non-indigenous snails in Hawai`i: complex management implications. Pacific Science 63: 339-347.

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