Dean E. Pearson, PhD

Research Ecologist

Rocky Mountain Research Station

dean.pearson@usda.gov

Publications & Products
Related
Education

Treesearch Publications

Mandy L. Slate, Phil G. Hahn, Yvette K. Ortega, Marisa Mancillas, Christoph Rosche, Dean E. Pearson. 2025. Plant regeneration trait syndromes, tradeoffs, and linkages to adult abundance for native and exotic grassland plants
Daniel Gorczynski, T. J. Clark-Wolf, Jedediah F. Brodie, Dean E. Pearson. 2025. Predicting community interactions under grizzly bear rewilding and anthropogenic change
Mandy L. Slate, Maria Sporbert, Isabell Hensen, Jose L. Hierro, Lotte Korell, Loralee Larios, David U. Nagy, Dean E. Pearson, Lauren Waller, Felicitas Wolf, Christoph Rosche. 2025. Drivers of phenological transitions in the seedling life stage
Xiaofei Li, Dean E. Pearson, Yvette K. Ortega, Lin Jiang, Shaopeng Wang, Qiang Gao, Deli Wang, Yann Hautier, Zhiwei Zhong. 2025. Nitrogen inputs suppress plant diversity by overriding consumer control
Dean E. Pearson, Alli L. W. DePuy, Marirose P. Kuhlman. 2025. Inspiring citizens and municipalities to initiate pollinator conservation: The urban pollinator matrix modeling tool
Dean E. Pearson, Yvette K. Ortega, Ylva Lekberg. 2024. Invaders break assembly rules to beat the natives: How cheatgrass cheats
Dean E. Pearson. 2024. Biological invasions: An overview
Tianyun Li, Zhiwei Zhong, Dean E. Pearson, Yvette K. Ortega, Wenjun Li, Yanan Li, Hui Zhu, Anita C. Risch, Deli Wang. 2023. Parasites as ecosystem modulators: Foliar pathogens suppress top-down effects of large herbivores
Jane E. Tuthill, Yvette K. Ortega, Dean E. Pearson. 2023. Seed size, seed dispersal traits, and plant dispersion patterns for native and introduced grassland plants
Mandy L. Slate, Rebecca A. Durham, Chuck Casper, Daniel Mummey, Philip Ramsey, Dean E. Pearson. 2023. No evidence of three herbicides and one surfactant impacting biological soil crusts
Dean E. Pearson, T. J. Clark-Wolf. 2023. Predicting ecological outcomes using fuzzy interaction webs
Jose L. Hierro, Walter A. Muino, Alejandro Farji-Brener, Marina C. Cock, Dean E. Pearson. 2023. Species introduction shifts a trait’s function from mutualism to antagonism: Elaiosomes in a myrmecochory cold spot
Dean E. Pearson, Yvette K. Ortega, Ozkan Eren, Diego Villarreal, Ylva Lekberg, Jose Hierro. 2023. Exotic success following disturbance explained by weak native resilience and ruderal exotic bias
Dean E. Pearson, Ozkan Eren, Yvette K. Ortega, Jose L. Hierro, Birsen Karakus, Sascha Kala, Lorinda Bullington, Ylva Lekberg. 2022. Combining biogeographical approaches to advance invasion ecology and methodology
Dean E. Pearson, Yvette K. Ortega. 2022. Restoration Catch-22: Overcoming issues with seed predation by small mammals when trying to restore habitat
T. J. Clark-Wolf, Philip G. Hahn, Eric Brelsford, Jaleen Francois, Nicolette Hayes, Beau Larkin, Philip Ramsey, Dean E. Pearson. 2022. Preventing a series of unfortunate events: Using qualitative models to improve conservation
Andrea R. Litt, Dean E. Pearson. 2022. A functional ecology framework for understanding and predicting animal responses to plant invasion
Dean E. Pearson, Yvette K. Ortega, Hillary E. Cimino, Daniel L. Mummy, Philip W. Ramsey. 2022. Does active plant restoration passively restore native fauna community structure and function?
Albert (Bud) E. Mayfield, Steven Seybold, Wendell R. Haag, Tracy Johnson, Becky K. Kerns, John Kilgo, Daniel Larkin, Rima Lucardi, Bruce Moltzan, Dean E. Pearson, John Rothlisberger, John Schardt, Michael K. Schwartz, Michael K. Young. 2021. Impacts of invasive species in terrestrial and aquatic systems in the United States.
John L. Maron, Philip G. Hahn, Karyn L. Hajek, Dean E. Pearson. 2021. Trade-offs between seed size and biotic interactions contribute to coexistence of co-occurring species that vary in fecundity
Dean E. Pearson, T. J. Clark, Philip G. Hahn. 2021. Evaluating unintended consequences of intentional species introductions and eradications for improved conservation management
Lukasz Dylewski, Yvette K. Ortega, Michal Bogdziewicz, Dean E. Pearson. 2021. Seed predator effects on plants: Moving beyond time-corrected proxies
Zhiwei Zhong, Xiaofei Li, Dirk Sanders, Yiming Liu, Ling Wang, Yvette K. Ortega, Dean E. Pearson, Deli Wang. 2021. Soil engineering by ants facilitates plant compensation for large herbivore removal of aboveground biomass
Jamie S. Sanderlin, Jessie Golding, Taylor Wilcox, Daniel Mason, Kevin S. McKelvey, Dean E. Pearson, Michael K. Schwartz. 2021. Occupancy modeling and resampling overcomes low test sensitivity to produce accurate SARS-CoV-2 prevalence estimates
Andrew M. Liebhold, Faith T. Campbell, Doria R. Gordon, Qinfeng Guo, Nathan P. P. Havill, Bradley Kinder, Richard A. MacKenzie, David R. Lance, Dean E. Pearson, Sharlene E. Sing, Travis Warziniack, Robert C. Venette, Denys Yemshanov. 2021. The Role of International Cooperation in Invasive Species Research
Therese M. M. Poland, Jennifer Juzwik, Allen Rowley, Cynthia Huebner, John Kilgo, Vanessa M. Lopez, Deanna H. Olson, Dean E. Pearson, Robert Progar, Robert Rabaglia, John Rothlisberger, Justin B. Runyon, Sharlene E. Sing. 2021. Management of Landscapes for Established Invasive Species
Jennifer Koch, Dean E. Pearson, Cynthia Huebner, Michael K. Young, Richard A. Sniezko. 2021. Restoration of Landscapes and Habitats Affected by Established Invasive Species
Woongsoon Jang, Justin S. Crotteau, Yvette K. Ortega, Sharon M. Hood, Christopher R. Keyes, Dean E. Pearson, Duncan C. Lutes, Anna Sala. 2021. Native and non-native understory vegetation responses to restoration treatments in a dry conifer forest over 23 years
John F. Gaskin, Erin Espeland, Casey D. Johnson, Diane L. Larson, Jane M. Mangold, Rachel A. McGee, Chuck Milner, Shishir Paudel, Dean E. Pearson, Lora B. Perkins, Chadley W. Prosser, Justin B. Runyon, Sharlene E. Sing, Zachary A. Sylvain, Amy J. Symstad, Daniel R. Tekiela. 2021. Managing invasive plants on Great Plains grasslands: A discussion of current challenges
Dean E. Pearson. 2020. Is there a breach in the barrier protecting humans from cervid chronic wasting disease?
Justin B. Taylor, Kristina L. Cass, David N. Armond, Matthew D. Madsen, Dean E. Pearson, Samuel B. St. Clair. 2020. Deterring rodent seed-predation using seed-coating technologies
Lukasz Dylewski, Yvette K. Ortega, Michal Bogdziewics, Dean E. Pearson. 2020. Seed size predicts global effects of small mammal seed predation on plant recruitment
Mandy L. Slate, Rebecca M. Durham, Dean E. Pearson. 2020. Strategies for restoring the form and function of lichen-moss biocrust communities
Lukasz Dylewski, Lukasz Myczko, Dean E. Pearson. 2019. Native generalist consumers interact strongly with seeds of the invasive wild cucumber (Echinocystis lobata)
John L. Maron, Karyn L. Hajek, Philip G. Hahn, Dean E. Pearson. 2019. Seedling recruitment correlates with seed input across seed sizes: implications for coexistence
Mandy L. Slate, Ragan M. Callaway, Dean E. Pearson. 2019. Life in interstitial space: Biocrusts inhibit exotic but not native plant establishment in semi-arid grasslands
Yvette K. Ortega, Morgan T. Valliant, Dean E. Pearson. 2019. To list or not to list: Using time since invasion to refine impact assessment for an exotic plant proposed as noxious
Dean E. Pearson, Morgan Valliant, Chris Carlson, Giles C. Thelen, Yvette K. Ortega, John L. Orrock, Matthew D. Madsen. 2019. Spicing up restoration: Can chili peppers improve restoration seeding by reducing seed predation?
Dean E. Pearson, Yvette K. Ortega, Justin B. Runyon, Jack L. Butler. 2018. Secondary invasion re-redefined: The distinction between invader-facilitated and invader-contingent invasions as subclasses of secondary invasion
Dean E. Pearson, Yvette K. Ortega, Ozkan Eren, Jose L. Hierro. 2018. Community assembly theory as a framework for biological invasions
Dean E. Pearson, Ozkan Eren, Yvette K. Ortega, Diego Villarreal, Muhyettin Senturk, M. Florencia Miguel, C. Miguel Weinzettel, Anibal Prina, Jose L. Hierro. 2018. Are invasive plants more abundant in the introduced versus native range?
Dean E. Pearson, Yvette K. Ortega, Diego Villarreal, Ylva Lekberg, Marina C. Cock, Ozkan Eren, Jose L. Hierro. 2018. The fluctuating resource hypothesis explains invasibility, but not exotic advantage following disturbance
John L. Maron, Karyn L. Hajek, Philip G. Hahn, Dean E. Pearson. 2018. Rodent seed predators and a dominant grass competitor affect coexistence of co-occurring forb species that vary in seed size
Rachel A. Loehman, Barbara J. Bentz, Gregg A. DeNitto, Robert E. Keane, Mary E. Manning, Jacob P. Duncan, Joel M. Egan, Marcus B. Jackson, Sandra Kegley, I. Blakey Lockman, Dean E. Pearson, James A. Powell, Steve Shelly, Brytten E. Steed, Paul J. Zambino. 2018. Effects of climate change on ecological disturbance in the Northern Rockies Region [Chapter 8]
Loralee Larios, Dean E. Pearson, John L. Maron. 2017. Incorporating the effects of generalist seed predators into plant community theory
Dean E. Pearson, Yvette K. Ortega, John L. Maron. 2017. The tortoise and the hare: Reducing resource availability shifts competitive balance between plant species
John L. Maron, Alyssa Laney Smith, Yvette K. Ortega, Dean E. Pearson, Ragan M. Callaway. 2016. Negative plant-soil feedbacks increase with plant abundance, and are unchanged by competition
Jennifer A. Rudgers, Rebecca A. Fletcher, Eric Olivas, Carolyn A. Young, Nikki D. Charlton, Dean E. Pearson, John L. Maron. 2016. Long‑term ungulate exclusion reduces fungal symbiont prevalence in native grasslands
Jennifer N. Smith, Douglas J. Emlen, Dean E. Pearson. 2016. Linking native and invader traits explains native spider population responses to plant invasion
Dean E. Pearson, Yvette K. Ortega, Justin B. Runyon, Jack L. Butler. 2016. Secondary invasion: The bane of weed management
Dean E. Pearson, Yvette K. Ortega, Jack L. Butler. 2015. Invasive Species Science Update (No. 8)
Dean E. Pearson, Yvette K. Ortega, Ozkan Eren, Jose L. Hierro. 2015. Quantifying "apparent" impact and distinguishing impact from invasiveness in multispecies plant invasions
Dean E. Pearson, Yvette K. Ortega, Jack L. Butler. 2014. Invasive Species Science Update (No. 7)
Sarah M. Pinto, Dean E. Pearson, John L. Maron. 2014. Seed dispersal is more limiting to grassland diversity than competition or seed predation
John L. Maron, Harald Auge, Dean E. Pearson, Lotte Korell, Isabell Hensen, Katharine N. Suding, Claudia Stein. 2014. Staged invasions across disparate grasslands: Effects of seed provenance, consumers and disturbance on productivity and species richness
Yvette K. Ortega, Leigh F. Greenwood, Ragan M. Callaway, Dean E. Pearson. 2014. Different responses of congeneric consumers to an exotic food resource: Who gets the novel resource prize?
Dean E. Pearson, J. L. Hierro, M. Chiuffo, D. Villarreal. 2014. Rodent seed predation as a biotic filter influencing exotic plant abundance and distribution
Dean E. Pearson, Nadia S. Icasatti, Jose L. Hierro, Benjamin J. Bird. 2014. Are local filters blind to provenance? Ant seed predation suppresses exotic plants more than natives
B. M. Connolly, Dean E. Pearson, R. N. Mack. 2014. Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion
Yvette K. Ortega, Dean E. Pearson. 2013. Spotted knapweed: Effects of climate change on the invasiveness and biological control
Dean E. Pearson, Yvette K. Ortega. 2013. Biogeography of plant invasions
Andrea R. Litt, Dean E. Pearson. 2013. Non-native plants and wildlife in the Intermountain West
Dean E. Pearson, Teal Potter, John L. Maron. 2012. Biotic resistance: Exclusion of native rodent consumers releases populations of a weak invader
John L. Maron, Dean E. Pearson, Teal Potter, Yvette K. Ortega. 2012. Seed size and provenance mediate the joint effects of disturbance and seed predation on community assembly
Yvette K. Ortega, Dean E. Pearson, Lauren P. Waller, Nancy J. Sturdevant, John L. Maron. 2012. Population-level compensation impedes biological control of an invasive forb and indirect release of a native grass
Dean E. Pearson, Yvette K. Ortega, Samantha J. Sears. 2012. Darwin's naturalization hypothesis up-close: Intermountain grassland invaders differ morphologically and phenologically from native community dominants
R. Zwolak, Dean E. Pearson, Yvette K. Ortega, E. E. Crone. 2012. Mechanisms driving postfire abundance of a generalist mammal
Dean E. Pearson, Ragan M. Callaway, John L. Maron. 2011. Biotic resistance via granivory: Establishment by invasive, naturalized, and native asters reflects generalist preference
Dean E. Pearson, Yvette K. Ortega. 2011. Invasive Species Science Update (No. 5)
Dean E. Pearson, Mee-Sook Kim, Jack L. Butler. 2011. Rocky Mountain Research Station invasive species visionary white paper
Dean E. Pearson, Steve Sutherland, Jack L. Butler, Jane Smith, Carolyn H. Sieg. 2011. I. Plants
Dean E. Pearson, Deborah M. Finch. 2011. V. Terrestrial vertebrates
John L. Maron, Dean E. Pearson. 2011. Vertebrate predators have minimal cascading effects on plant production or seed predation in an intact grassland ecosystem
Yvette K. Ortega, Dean E. Pearson. 2011. Long-term effects of weed control with picloram along a gradient of spotted knapweed invasion
John L Maron, Dean E. Pearson, Robert J. Fletcher. 2010. Counterintuitive effects of large-scale predator removal on a midlatitude rodent community
Yvette K. Ortega, Dean E. Pearson. 2010. Effects of picloram application on community dominants vary with initial levels of spotted knapweed (Centaurea stoebe) invasion
Dean E. Pearson. 2010. Trait- and density-mediated indirect interactions initiated by an exotic invasive plant autogenic ecosystem engineer
John L. Maron, Dean E. Pearson, Stephen M. Hovick, Walter P. Carson. 2010. Funding needed for assessments of weed biological control
Rafal Zwolak, Dean E. Pearson, Yvette K. Ortega, Elizabeth E. Crone. 2010. Fire and mice: Seed predation moderates fire's influence on conifer recruitment
Mary Bricker, Dean E. Pearson, John Maron. 2010. Small-mammal seed predation limits the recruitment and abundance of two perennial grassland forbs
Jack L. Butler, Dean E. Pearson, Mee-Sook Kim. 2009. Invasive Species Working Group: Research Summary and Expertise Directory
Yvette K. Ortega, Dean E. Pearson. 2009. Factors influencing plant invasiveness
Dean E. Pearson, Yvette K. Ortega. 2009. Managing invasive plants in natural areas: Moving beyond weed control
Dean E. Pearson. 2009. Biological invasions on oceanic islands: Implications for island ecosystems and avifauna
Elizabeth E. Crone, Marilyn Marler, Dean E. Pearson. 2009. Non-target effects of broadleaf herbicide on a native perennial forb: a demographic framework for assessing and minimizing impacts
Dean E. Pearson. 2009. Invasive plant architecture alters trophic interactions by changing predator abundance and behavior
Dean E. Pearson. 2008. Understanding the side effects of classical biological control
Kerry Foresman, Elizabeth Crone, Dean E. Pearson, Yvette K. Ortega, Rafal Zwolak. 2008. Are mice eating up all the pine seeds?
Sharon Ritter, Greg G. Jones, Alan E. Watson, Ward McCaughey, Mick Harrington, Rafal Zwolak, Kerry Foresman, Elizabeth Crone, Dean E. Pearson, Yvette K. Ortega, Dan Loeffler. 2008. ECO-Report - Finding common ground: Montana Forest Restoration Committee
Dean E. Pearson, Robert J. Fletcher. 2008. Mitigating exotic impacts: restoring native deer mouse populations elevated by an exotic food subsidy
Dean E. Pearson, Ragan M. Callaway. 2008. Weed biocontrol insects reduce native plant recruitment through second-order apparent competition
Dean E. Pearson, Ragan M. Callaway. 2006. Biological control agents elevate hantavirus by subsidizing deer mouse populations
Katharine R. Shick, Dean E. Pearson, Leonard F. Ruggiero. 2006. Forest habitat associations of the golden-mantled ground squirrel: Implications for fuels management
Nancy Sturdevant, Sandy Kegley, Yvette K. Ortega, Dean E. Pearson. 2006. Evaluation of establishment of Cyphocleonus achates and its potential impact on spotted knapweed
Dean E. Pearson, Ragan M. Callaway. 2005. Indirect nontarget effects of host-specific biological control agents: Implications for biological control
Dean E. Pearson. 2005. Biological control is more than just natural enemies
Yvette K. Ortega, Dean E. Pearson. 2005. Weak vs. strong invaders of natural plant communities: Assessing invasibility and impact
Janie Canton-Thompson, Jim Saveland, Sharon Ritter, Yvette K. Ortega, Dean E. Pearson, Mick Harrington, Elaine K. Sutherland, Clint Cook, Greg Jones. 2004. ECO-Report - Great issues, great diversions
Dean E. Pearson, Ragan M. Callaway. 2004. Response to Thomas et al.: Biocontrol and indirect effects
Yvette K. Ortega, Dean E. Pearson, Kevin S. McKelvey. 2004. Effects of biological control agents and exotic plant invasion on deer mouse populations
Janie Canton-Thompson, Marcia Patton-Mallory, Sue Heald, Sharon Ritter, Robert D. Pfister, Dean E. Pearson, Yvette K. Ortega, Alan E. Watson, Elaine K. Sutherland, Greg Jones. 2003. ECO-Report - The case for research: How it makes a difference to managers
Dean E. Pearson, Ragan M. Callaway. 2003. Indirect effects of host-specific biological control agents
Dean E. Pearson, Leonard F. Ruggiero. 2003. Transect versus grid trapping arrangements for sampling small-mammal communities
Dean E. Pearson, Yvette K. Ortega, Len Ruggiero. 2003. Trap-induced mass declines in small mammals: Mass as a population index
Kevin S. McKelvey, Dean E. Pearson. 2001. Population estimation with sparse data: The role of estimators versus indices revisited
Yvette K. Ortega, Dean E. Pearson. 2001. Occurrences of the western skink (Eumeces skiltonianus) in grasslands of western Montana
Dean E. Pearson, Leonard F. Ruggiero. 2001. Test of the prey-base hypothesis to explain use of red squirrel midden sites by American martens
Dean E. Pearson, Yvette K. Ortega. 2001. An indirect dispersal pathway for spotted knapweed seeds via deer mice and great-horned owls
Dean E. Pearson, Yvette K. Ortega, Kevin S. McKelvey, Leonard F. Ruggiero. 2001. Small mammal communities and habitat selection in Northern Rocky Mountain bunchgrass: Implications for exotic plant invasions
Dean E. Pearson. 2000. Evidence of autumn breeding in red squirrels, Tamiasciurus hudsonicus, in western Montana
Dean E. Pearson, Kevin S. McKelvey, Leonard F. Ruggiero. 2000. Non-target effects of an introduced biological control agent on deer mouse ecology
Len Ruggiero, Dean E. Pearson. 2000. Presence/absence as a metric for monitoring vertebrate populations
Dean E. Pearson. 2000. Small mammals of the Bitterroot National Forest: Ecological significance and guidelines for management
Janie Canton-Thompson, Jane Kapler Smith, Greg G. Jones, Perry J. Brown, Stephen F. Arno, Orville L. Daniels, Dale A. Burk, Colin C. Hardy, Dave Silvieus, Kristi D. Pflug, Bruce Winhorst, Brooke Thompson, Yvette K. Ortega, Kevin S. McKelvey, Tom Thompson, Dean E. Pearson, Cathy Stewart, Janet Sullivan. 1999. ECO-Report - 1999 Symposium highlights five years of learning
Steven W. Buskirk, Leonard F. Ruggiero, Keith B. Aubry, Dean E. Pearson, John R. Squires, Kevin S. McKelvey. 1999. Comparative ecology of lynx in North America [Chapter 14]
Dean E. Pearson. 1999. Small mammals of the Bitterroot National Forest: A literature review and annotated bibliography
Kerry R. Foresman, Dean E. Pearson. 1998. Comparison of proposed survey procedures for detection of forest carnivores
Leonard F. Ruggiero, Dean E. Pearson, Stephen E. Henry. 1998. Characteristics of American marten den sites in Wyoming

University of Montana, Ph.D., Organismal Biology and Ecology, 2005
University of Montana, M.A.S., Zoology, 1995
University of Montana, B.S., Wildlife Biology, 1992

Last updated March 10, 2026

Dean E. Pearson, PhD

Treesearch Publications

Wildlife Ecology

Invasive Species Working Group

Articles

Inspiring citizens to initiate pollinator conservation