Ian Pearse, PhD
Ian is an ecologist who works on plants and insects.
Ian conducts research at the individual, population, community, and ecosystem level scales. His work focuses on plant-insect interactions and involves work on endangered insects such as bumble bees, strategies to map and control invasive plants, the chemical ecology and behaviors that affect herbivory, and the boom and bust seed production dynamics of many trees (i.e. mast seeding). His work informs management decisions made by the US Fish and Wildlife Service, National Parks, and a variety of other groups. Ian is especially fond of oak trees and spends a considerable amount of time staring up into them with the vague excuse of counting acorns, gall wasps, or rates of herbivory.
Professional Experience
2016 Postdoctoral work, University of California, Davis
2014-2015 Postdoctoral work, Illinois Natural History Survey
2012-2013 Postdoctoral work, Cornell University
Education and Certifications
PhD Entomology, University of California, Davis, 2011
BS Plant Biology, University of Illinois, Urbana-Champaign 2004
Affiliations and Memberships*
International Oak Society
Ecological Society of America
Entomological Society of America
Science and Products
Phylogenetic escape from pests reduces pesticides on some crop plants
Direct and indirect effects of a keystone engineer on a shrubland-prairie food web
Negative effects of an allelopathic invader on AM fungal plant species drive community‐level responses
Associational effects of plant ontogeny on damage by a specialist insect herbivore
Generalizing indirect defense and resistance of plants
Mast seeding patterns are asynchronous at a continental scale
Biogeography and phylogeny of masting: Do global patterns fit functional hypotheses?
Life-history plasticity and water-use trade-offs associated with drought resistance in a clade of California jewelflowers
A modeling workflow that balances automation and human intervention to inform invasive plant management decisions at multiple spatial scales
Population ecology and spatial synchrony in abundance within and among populations of valley oak (Quercus lobata) leaf gall wasps
Aridity drives spatiotemporal patterns of masting across the latitudinal range of a dryland conifer
From theory to experiments for testing the proximate mechanisms of mast seeding: An agenda for an experimental ecology
Non-USGS Publications**
http://onlinelibrary.wiley.com/doi/10.1111/nph.14114/full
http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12554/pdf
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152537
http://onlinelibrary.wiley.com/doi/10.1890/14-0297.1/ful
http://onlinelibrary.wiley.com/doi/10.1890/15-0342.1/full
http://link.springer.com/article/10.1007/s10531-010-9956-0
http://www.pnas.org/content/106/43/18097.short
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.2005.01307.x/full
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
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Filter Total Items: 61
Phylogenetic escape from pests reduces pesticides on some crop plants
Pesticides are a ubiquitous component of conventional crop production but come with considerable economic and ecological costs. We tested the hypothesis that variation in pesticide use among crop species is a function of crop economics and the phylogenetic relationship of a crop to native plants because unrelated crops accrue fewer herbivores and pathogens. Comparative analyses of a dataset of 93AuthorsIan Pearse, Jay RosenheimDirect and indirect effects of a keystone engineer on a shrubland-prairie food web
Keystone engineers are critical drivers of biodiversity throughout ecosystems worldwide. Within the North American Great Plains, the black‐tailed prairie dog is an imperiled ecosystem engineer and keystone species with well‐documented impacts on the flora and fauna of rangeland systems. However, because this species affects ecosystem structure and function in myriad ways (i.e., as a consumer, a prAuthorsCourtney Duchardt, Lauren M. Porensky, Ian PearseNegative effects of an allelopathic invader on AM fungal plant species drive community‐level responses
The mechanisms causing invasive species impact are rarely empirically tested, limiting our ability to understand and predict subsequent changes in invaded plant communities. Invader disruption of native mutualistic interactions is a mechanism expected to have negative effects on native plant species. Specifically, disruption of native plant‐fungal mutualisms may provide non‐mycorrhizal plant invadAuthorsMorgan Roche, Ian Pearse, Lalasia Bialic-Murphy, Stephanie N Kivlin, Helen Sofaer, Susan KaliszAssociational effects of plant ontogeny on damage by a specialist insect herbivore
Intraspecific variation in plant traits is a major cause of variation in herbivore feeding and performance. Plant defensive traits change as a plant grows, such that ontogeny may account for a substantial portion of intraspecific trait variation. We tested how the ontogenic stage of an individual plant, of an individual in the context of its neighboring plants, and of a patch of plants with mixedAuthorsOlivia Cope, Zoe Becker, Paul J. Ode, Paul Ryan, Ian PearseGeneralizing indirect defense and resistance of plants
Indirect defence, the adaptive top‐down control of herbivores by plant traits that enhance predation, is a central component of plant–herbivore interactions. However, the scope of interactions that comprise indirect defence and associated ecological and evolutionary processes has not been clearly defined. We argue that the range of plant traits that mediate indirect defence is much greater than prAuthorsIan Pearse, Eric LoPresti, Robert N. Schaeffer, William C. Wetzel, Kailen A. Mooney, Jared G. Ali, Paul J. Ode, Micky D. Eubanks, Judith L. Bronstein, Marjorie G. WeberMast seeding patterns are asynchronous at a continental scale
Resource pulses are short duration, high magnitude, rare events that drive the dynamics of both plant and animal populations and communities1. Mast seeding is perhaps the most common type of resource pulse occurring in terrestrial ecosystems2, is characterized by the synchronous and highly variable production of seed crops by a population of perennial plants3,4, and is widespread both taxonomicallAuthorsJ. M. LaMontagne, Ian Pearse, David A. Greene, W. D. KoenigBiogeography and phylogeny of masting: Do global patterns fit functional hypotheses?
1) Interannual variability of seed crops (CVp) has profound consequences for plant populations and food webs, where high CVp is termed ‘masting’. Here we ask: is global variation in CVp better predicted by plant or habitat differences consistent with adaptive economies of scale, in which flower and seed benefits increase disproportionately during mast years; or to passive mechanisms, in which seedAuthorsIan Pearse, Jalene LaMontagne, Michael Lordon, Andrew Hipp, Walter D. KoenigLife-history plasticity and water-use trade-offs associated with drought resistance in a clade of California jewelflowers
Water limitation is a primary driver of plant geographic distributions and individual plant fitness. Drought resistance is the ability to survive and reproduce despite limited water, and numerous studies have explored its physiological basis in plants. However, it is unclear how drought resistance and trade-offs associated with drought resistance evolve within plant clades. We quantified the relatAuthorsIan S. Pearse, Jessica Aguilar, Sharon StraussA modeling workflow that balances automation and human intervention to inform invasive plant management decisions at multiple spatial scales
Predictions of habitat suitability for invasive plant species can guide risk assessments at regional and national scales and inform early detection and rapid-response strategies at local scales. We present a general approach to invasive species modeling and mapping that meets objectives at multiple scales. Our methodology is designed to balance trade-offs between developing highly customized modelAuthorsNicholas E. Young, Catherine S. Jarnevich, Helen Sofaer, Ian Pearse, Julia Sullivan, Peder Engelstad, Thomas J. StohlgrenPopulation ecology and spatial synchrony in abundance within and among populations of valley oak (Quercus lobata) leaf gall wasps
What factors drive population variability through space and time? Here we assess patterns of abundance of seven species of gall wasps in three genera occurring on the leaves of valley oaks (Quercus lobata ) at 10 sites throughout this species' statewide range in California, from 2000 to 2006. Our primary goals were to understand the factors driving variability in gall abundance and to assess the eAuthorsBrian Barringer, Walter D. Koenig, Ian Pearse, Jean KnopsAridity drives spatiotemporal patterns of masting across the latitudinal range of a dryland conifer
Masting, or the synchronous and irregular production of seed crops, is controlled by environmental conditions and resource budgets. Increasing temperatures and shifting precipitation regimes may alter the frequency and magnitude of masting, especially in species that experience chronic resource stress. Yet the effects of a changing climate on seed production are unlikely to be uniform across populAuthorsAndreas Wion, Peter Weisberg, Ian Pearse, Miranda RedmondFrom theory to experiments for testing the proximate mechanisms of mast seeding: An agenda for an experimental ecology
Highly variable and synchronised production of seeds by plant populations is called masting and is implicated in many important ecological processes, but how it arises remains poorly understood. The lack of experimental studies prevents underlying mechanisms from being explicitly tested, and thereby precludes meaningful predictions on the consequences of changing environments for plant reproductivAuthorsM. Bogdziewicz, Davide Ascoli, Andrew Hacket-Pain, W. D. Koenig, Ian Pearse, Mario B. Pesendorfer, A. Satake, P. Thomas, Giorgio Vacchiano, T. Wohlgemuth, A. TanentzapNon-USGS Publications**
Pearse, I.S., Koenig, W.D., Kelly, D. 2016. Mechanisms of mast seeding: resources, weather, cues, and selection. The New Phytologist 212: 546-562
http://onlinelibrary.wiley.com/doi/10.1111/nph.14114/fullMescher, M.C. and Pearse, I.S. 2016. Communicative interactions involving plants: information, evolution, and ecology Current Opinion in Plant Biology 32: 69-76. http://www.sciencedirect.com/science/article/pii/S136952661630098XKrimmel, B.A., Pearse, I.S. 2016. Tolerance and phenological avoidance of herbivory in tarweed species. Ecology 97: 1357-1363. http://onlinelibrary.wiley.com/doi/10.1890/15-1454.1/fullPesendorfer, M., Koenig, W.D., Pearse, I.S., Knops, J.M.H., Funk, K. 2016. Individual resource limitation combined with population-wide pollen availability drives masting in the valley oak (Quercus lobata). Journal of Ecology 104: 637-645.
http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12554/pdfMoriera, X., Sampedro, L., Zas, R., Pearse, I.S. 2016. Defensive Traits in Young Pine Trees Cluster into Two Divergent Syndromes Related to Early Growth Rate. PlosOne. 0152537.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152537Koenig, W.D., Alejano, R., Dolores Carbonero, M., Fernández-Rebollo, P., Knops, J.M.H, Maranon, T., Padilla-Diaz, C.M., Pearse, I.S., Perez-Ramon, I.M., Pesendorfer, M.B. 2016. Is the relationship between mast‐seeding and weather in oaks related to their life‐history or phylogeny? Ecology 97: 2603-2615. http://onlinelibrary.wiley.com/doi/10.1002/ecy.1490/fullYguel, B., Jactel, H., Pearse, I.S., Moen, D., Winter, M., Hortal, J., Helmus, M., Kühn, I., Pavoine, S., Purschke, O., Weiher, E., Violle, C., Ozinga, W., Braendle M., Bartish I., Prinzing, A. 2016. The Evolutionary Legacy of Diversification Predicts Ecosystem Function. The American Naturalist. http://www.journals.uchicago.edu/doi/abs/10.1086/687964Pearse, I.S., Koenig, W.D., Funk, K.A., Presendorfer, M.B. 2015. Pollen limitation and flower abortion in a wind-pollinated, masting tree. Ecology 96: 587-593
http://onlinelibrary.wiley.com/doi/10.1890/14-0297.1/fulKoenig, W.D., Knops, J.M.H., Carmen, W.J., Pearse, I.S. 2015. What drives masting? The phenological synchrony hypothesis. Ecology 96: 184-192. http://onlinelibrary.wiley.com/doi/10.1890/14-0819.1/fullMcMahon, D., Pearse, I.S., Koenig, W.D., Walters, E.L. 2015. Oak community shift and woodpecker population increase over three decades in California woodland. Canadian Journal of Forest Research. http://www.nrcresearchpress.com/doi/abs/10.1139/cjfr-2015-0035#.V__Zq_krJ9MLoPresti, E.F., Pearse, I.S., Charles, G.K. 2015. A plant siren song: columbines provision mutualist arthropods by attracting and killing passerby insects. Ecology (featured in Science and Discover Magazine)
http://onlinelibrary.wiley.com/doi/10.1890/15-0342.1/fullPearse, I.S., Altermatt, F. 2015. Out of sample predictions from plant-insect food webs: robustness to missing and erroneous trophic interaction records. Ecological Applications. http://onlinelibrary.wiley.com/doi/10.1890/14-1463.1/fullPearse, I.S., Baty, J.H., Herrmann, D.L., Sage, R., Koenig, W.D. 2015. Leaf phenology mediates provenance differences in herbivore populations on valley oaks in a common garden. Ecological Entomology. http://onlinelibrary.wiley.com/doi/10.1111/een.12219/full
Hughes, K.A., Pearse, I.S., Gof-Tizsa, P., Karban, R. 2015. Individual-level differences in generalist caterpillar responses to a plant-plant signal. Ecological Entomology. http://onlinelibrary.wiley.com/doi/10.1111/een.12224/fullPearse, I.S., Funk, K.A., Kraft, T.S., Koenig, W.D. 2015. Lagged effects of early‑season herbivores on valley oak fecundity. Oecologia 178: 361-368. http://link.springer.com/article/10.1007/s00442-014-3193-2
Petchey, O.L., Pontarp, M., Massie, T.N., Kéfi, S., Ozgul, A., Weilenmann, M., Palamara, G.C., Altermatt, F., Matthews, B.J., Levine, J.M., Childs, D.Z., McGill, B.J., Schaepman, M.E., Schmid, B., Spaak, P., Beckerman, A.P., Pennekamp, F., Pearse, I.S. 2015. The Ecological Forecast Horizon, and examples of its uses and determinants. Ecology Letters. http://onlinelibrary.wiley.com/doi/10.1111/ele.12443/fullPearse, I.S., Hipp, A.L. 2014. Native plant diversity increases herbivory to non-natives. Proceedings of the Royal Society – B 281: 20141841. http://rspb.royalsocietypublishing.org/content/281/1794/20141841.shortDesurmont, G., Pearse, I.S. Alien plants versus alien herbivores: does it matter who is non-native in a novel trophic interaction? Current Opinion in Insect Science 2: 20-25. http://www.sciencedirect.com/science/article/pii/S221457451400035Krimmel, B.A., Pearse, I.S. 2014. Generalist and sticky plant specialist predators suppress herbivores on a sticky plant. Arthropod Plant Interactions 8: 403-410. http://link.springer.com/article/10.1007/s11829-014-9318-zPearse, I.S., Cobb, R.C., Karban, R. 2014. The phenology substrate match hypothesis explains decomposition rates of evergreen and deciduous oak leaves. Journal of Ecology 102: 28-35. http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12182/fullKoenig, W.D., Walters, E.L., Pearse, I.S., Knops, J.M.H. 2014. Serotiny in California oaks. Madroño 61(2): 151-158. http://www.bioone.org/doi/full/10.3120/0024-9637-61.2.151
Pearse, IS, Koenig, WD, Knops, JMH. 2014. Cues versus proximate drivers: testing the mechanism behind masting behavior. Oikos 123: 179-184 http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0706.2013.00608.x/fullKarban, R., Huntzinger, M., Pearse, I.S. 2014. How to Do Ecology: A Concise Handbook, 2nd edition. Princeton University Press, Princeton. http://press.princeton.edu/titles/10284.htmlPearse, I.S., Bastow, J.L., Tsang, A. 2014. Radish introduction affects soil biota but has a positive impact on the growth of a native plant. Oecologia 174: 471-478. http://link.springer.com/article/10.1007/s00442-013-2779-4Pearse, I.S., Griswold, S., Pizarro, D., Koenig, W.D. 2014. Stage and size structure of three species of oaks in central coastal California. Madroño 61(1): 1-8. http://www.bioone.org/doi/abs/10.3120/0024-9637-61.1.1
Pearse, I.S., Gee, W.S., Beck, J.J. 2013. Headspace volatiles from 52 oak species advertise induction, species identity, and evolution, but not defense. Journal of Chemical Ecology 39: 90-100. http://link.springer.com/article/10.1007/s10886-012-0224-5Pearse, I.S. and Altermatt, F. 2013. Extinction cascades partially estimate observed herbivore losses in a Lepidoptera-plant food web. Ecology 94(8): 1785-1794 (Cover article). http://onlinelibrary.wiley.com/doi/10.1890/12-1075.1/fullPearse, I.S., Hughes, K., Shiojiri, K., Ishizaki, S., Karban, R. 2013. Interplant volatile signaling in willows: revisiting the original talking trees. Oecologia 172: 869-875 (Cover article). http://link.springer.com/article/10.1007/s00442-013-2610-2Pearse, I.S. and Karban, R. 2013. Leaf drop affects herbivory in oaks. Oecologia 173: 925-932. http://link.springer.com/article/10.1007/s00442-013-2689-5
Pearse, I.S., Harris, D.J., Karban, R., Sih, A. 2013.Predicting novel herbivore-plant interactions. Oikos 122: 1554-1564. http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0706.2013.00527.x/fullPearse, I.S. and Altermatt F. 2013. Predicting novel trophic interactions in a non-native world. Ecology Letters 16: 1088-1094. http://onlinelibrary.wiley.com/doi/10.1111/ele.12143/fullKrimmel, B.A. and Pearse, I.S. 2013. Sticky plants trap invertebrate carrion to enhance indirect defense. Ecology Letters. 16: 219-224 (featured in Nature). http://onlinelibrary.wiley.com/doi/10.1111/ele.12032/fullSavchenko, T., Pearse, I.S., Karban, R., DeHesh, K. 2013. Insect feeding habits determine the composition of hydroperoxide lyase-derived metabolites. The Plant Journal 73: 653-662. http://onlinelibrary.wiley.com/doi/10.1111/tpj.12064/full
Pearse, I.S., Karban, R. 2013. Do plant-plant signals mediate herbivory consistently in multiple taxa and ecological contexts? Journal of Plant Interactions 8(3): 203-206. http://www.tandfonline.com/doi/abs/10.1080/17429145.2013.765511Pearse, I.S. and Hipp, A.L. 2012. Global patterns of leaf defenses in oak species. Evolution. 66(7): 2272-2286. http://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2012.01591.x/full
Herrmann, D.L., Pearse, I.S., Baty, J.H. 2012. Drivers of specialist herbivore diversity across 10 cities. Landscape and Urban Planning 108: 123-130. http://www.sciencedirect.com/science/article/pii/S0169204612002617Pearse, I.S., Parensky, L.M., Yang, L.H., Stanton, M.L., Karban, R., Bhattacharyya, L., Dove, K., Higgins, A., Kamaroff, C., Kirk, T., Knight, C., Koch, R., Rollins, H., Tanner, K., Cox, R. 2012. Complex consequences of herbivory and interplant cues in three annual plants. PlosOne 7(5): e38105. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038105Pearse, I.S. and Baty, J.H. 2012. The predictability of traits and ecological interactions on 17 different crosses of hybrid oaks. Oecologia 169: 489-497. http://link.springer.com/article/10.1007/s00442-011-2216-5
Pearse, I.S. 2012. The role of leaf defensive traits in oaks on the preference and performance of a polyphagous herbivore, Orgyia vetusta. Ecological Entomology 36(5): 635-642. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2311.2011.01308.x/fullAltermatt, F., Pearse, I.S. 2011. Similarity and specialization of the larval versus adult diets of European butterflies and moths. The American Naturalist 178(3): 372-378. http://www.jstor.org/stable/10.1086/661248?seq=1#page_scan_tab_contentsJoseph, M., Gentles, M., Pearse, I.S. 2011. The parasitoid community of Andricus quercuscalifornicus (Hymenoptera: Cynipidae) is associated with gall size and host phenology. Biodiversity and Conservation 20: 203-216.
http://link.springer.com/article/10.1007/s10531-010-9956-0Pearse I.S. 2011. Novel herbivore-plant interactions: Evidence from non-native oaks (Dissertation) U. California – Davis. http://gradworks.umi.com/34/99/3499479.html
Pearse, I.S. 2010. Bird rookeries have different effects on different feeding guilds of herbivores and alter the feeding behavior of a common caterpillar. Arthropod Plant Interactions 4: 189-195. http://link.springer.com/article/10.1007/s11829-010-9098-zKarban, R., C. Karban, Huntzinger, M., Pearse, I., Crutsinger, G. 2010. Diet mixing enhances the performance of a generalist caterpillar, Platyprepia virginalis. Ecological Entomology 35(1): 92-99. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2311.2009.01162.x/fullPearse, I.S. and A.L. Hipp. 2009. Phylogenetic and trait similarity to a native species predict herbivory on non-native oaks. Proceedings of the National Academy of Sciences of the United States of America 106(43): 18097-18102. (Cover article)
http://www.pnas.org/content/106/43/18097.short
Pearse, I, Zhu, Y, Murray, E, Dudeja, P, Ramaswamy, K, Malakooti, J. 2007. Sp1 and Sp3 control constitutive expression of the human NHE2 promoter by interactions with the proximal promoter and the transcription initiation site. Biochemical Journal 407: 101-111. http://www.biochemj.org/content/407/1/101.abstract
Pearse, IS, Krügel, T, Baldwin, IS. 2006. Innovation in anti-herbivore defense systems during neopolyploidy - the functional consequences of instantaneous speciation. The Plant Journal 47: 196-210. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2006.02776.x/fullPearse, I.S., Heath, K.D., Cheeseman, J.M. 2006. Biochemical and ecological characterization of two peroxidase isoenzymes from the mangrove, Rhizophora mangle. Plant, Cell and Environment 28: 612-622 (Cover article).
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.2005.01307.x/full**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government