Ian Pearse is an Ecologist in the invasive species branch of the Fort Collins Science Center.
Ian Pearse is a research ecologist at the Fort Collins Science Center. Ian received a Ph.D. in Entomology from U.C. Davis in 2011. He has conducted research on plant-insect interactions and community ecology, focusing on ways to predict new interactions between introduced species such as plants and herbivorous insects. As part of the invasive species branch, Ian is applying that work to anticipate the impacts of destructive plant and insect invasions.
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
Ph.D. University of California, Davis, 2011
B.S. University of Illinois, 2004
Science and Products
Developing a macroecological understanding of invasive plant impacts based on abundance and trait data
Understanding invasive plant impacts can provide insight into community assembly and inform the development of successful management strategies. The impacts of invasive species depend on how they alter patterns of abundance within recipient communities and on the characteristics of the invaders and the affected species. Research has suggested that common species may be more impacted by invasions,
Filter Total Items: 17
INHABIT species potential distribution across the contiguous United States (ver. 3.0, January 2023)
We developed habitat suitability models for invasive plant species selected by Department of Interior land management agencies. We applied the modeling workflow developed in Young et al. 2020 to species not included in the original case studies. Our methodology balanced trade-offs between developing highly customized models for a few species versus fitting non-specific and generic models for numer
Data on how Lepidium draba responds to damage of clones
A greenhouse experiment was conducted to test the ability of the invasive clonal plant, Lepidium draba, to cope with damage to local and different ramets. The experiment was arranged in a fully factorial split-pot design that was blocked by bench position and provenance population of the plant. Plants were grown in 'split pots', where two adjoining pots were glued together with a small opening for
Data for a lab study of the effects of diet variability on the interactions between a Lepidopteran herbivore and its parasitoid
Data were collected from two laboratory rearing experiments conducted in 2018 of Trichoplusia ni caterpillars that had been parasitized by Copidosoma floridanum parasitoids. In the first experiment, parasitized caterpillars were fed artificial diets spiked with increasing concentrations of the phytochemical xanthotoxin in order to assess the effect of xanthotoxin on parasitoid success. In the seco
Greenhouse observations of plant herbivore interactions on Lepidium draba to test effects of ontogenic variability
Data were collected from an experimental greenhouse study in which Lepidium draba plants were grown from root cuttings to create plants at different ontogenic stages. Plants were arranged in mixed-age and single-age stands and exposed to the Lepidopteran herbivore, diamondback moth caterpillars. The success (biomass gain and surivival) of herbivores, the amount of feeding, and the growth of plants
Californian crop pests, pesticide applications, and phylogenetic information of crops
Information on pesticide applications, crop pests, and phylogenetic affinities between Californian crops and regional native plants were compiled. Data was collected to inform models of pesticide applications and host use of pests among California's 93 major crops. Pesticide data was assembled from California Department of Pesticide Regulation records, pest information was assembled from the Calif
Data on the impacts of garlic mustard from a weeding experiment in Pennsylvania 2006-2016
Data were collected on the abundance of plants in a 10-year weeding experiment of garlic mustard, located at Trillium Trails Park in Pennsylvania. Garlic mustard was weeded annually to suppress its abundance, and the impacts of garlic mustard were measured based on the response of the plant community to garlic mustard weeding. Because garlic mustard is known to suppress mycorrhizal fungi, the myco
Data on prairie dogs, plants, arthropod biomass, and birds for Thunder Basin, Wyoming in 2017
Data were collected in 2017 by researchers at the USGS, USDA-ARS, and University of Wyoming on the food webs of plants, prairie dogs, arthropods, and birds in the Thunder Basin National Grassland. Data were collected from 87 sites in order to parameterize a structural equation model linking prairie dog impacts to changes in vegetation, arthropods, and birds. Abiotic information such as topographic
Data on interannual seed set variation, weather, and reproductive traits for global plants
Data were collected on seed production dynamics of long-lived plants, reproductive plant traits of those plant species, and weather variability for sites where those species live. Data include the coefficient of variation in seed production over time, the variation (coefficient of variation or standard deviation) in weather over years, and reproductive traits such as pollination mode and seed disp
Data on cone production in pinyon pine in the Southwestern USA from 2003-2016
Data were collected on pinyon pine cone production using the cone scar method (Redmond et al 2016 Forest Ecology and Management) from 2003-2016 among sites in the Southwest USA. Long-term weather data (Vapor Pressure Deficits and monsoonality) were associated with cone scar data to assess weather-correlates of cone production.
Data on gall wasp abundance and biomass on valley oak and blue oak trees in California
Gall abundance and biomass was recorded on marked valley oak and blue oak individuals throughout California. Galls, mostly caused by cynipid gall wasps, were identified to species. Sampling effort per tree was recorded as the number of leaves searched for gall wasps. Leaves were taken from two branches per tree using pole pruners, and total galls per tree were summed in each observation. Annual ob
Long term cone production of white spruce throughout boreal forests in North America
Data were compiled on the seed production of white spruce in order to assess the long-term trends in seed production over the past 60 years in North American boreal forests. Data on cone production was merged with annual weather, teleconnection indices such as ENSO, and historical fires in boreal forests.
Data on interannual variability of seed production, nutrient, and weather for 219 plant species
We calculated estimates describing interannual variation in seed production for series of long-term seed or fruit production in 219 plant species. For each plant species, we compiled estimates of foliar nutrient concentrations as well as productivity and weather at the site of observation. Data was compiled in order to test whether interannual variation in seed production was greater in species wi
Filter Total Items: 39
Addressing detection uncertainty in Bombus affinis (Hymenoptera: Apidae) surveys can improve inferences made from monitoring
The U.S. Fish and Wildlife Service developed national guidelines to track species recovery of the endangered rusty patched bumble bee [Bombus affinis Cresson (Hymenoptera: Apidae)] and to investigate changes in species occupancy across space and time. As with other native bee monitoring efforts, managers have specifically acknowledged the need to address species detection uncertainty and determine
Herbivory changes biomass allocation but does not induce resistance among clones of an invasive plant
Inducible responses to herbivores can be either localized or spread systemically throughout a plant. The ways in which clonal plants integrate their response to herbivores among clonal ramets is not well understood. Yet, this is important to understand the impacts that herbivores may have on clonal plants. We conducted a factorial split-plot greenhouse experiment to determine whether resistance is
INHABIT: A web-based decision support tool for invasive plant species habitat visualization and assessment across the contiguous United States
Narrowing the communication and knowledge gap between producers and users of scientific data is a longstanding problem in ecological conservation and land management. Decision support tools (DSTs), including websites or interactive web applications, provide platforms that can help bridge this gap. DSTs can most effectively disseminate and translate research results when producers and users collabo
The importance of forests in bumble bee biology and conservation
Declines of many bumble bee species have raised concerns because of their importance as pollinators and potential harbingers of declines among other insect taxa. At present, bumble bee conservation is predominantly focused on midsummer flower restoration in open habitats. However, a growing body of evidence suggests that forests may play an important role in bumble bee life history. Compared with
Modes of climate variability bridge proximate and evolutionary mechanisms of masting
There is evidence that variable and synchronous reproduction in seed plants (masting) correlates to modes of climate variability, e.g. El Niño Southern Oscillation and North Atlantic Oscillation. In this perspective, we explore the breadth of knowledge on how climate modes control reproduction in major masting species throughout Earth's biomes. We posit that intrinsic properties of climate modes (
Understanding mast seeding for conservation and land management
Masting, the intermittent and synchronous production of large seed crops, can have profound consequences for plant populations and the food webs that are built on their seeds. For centuries, people have recorded mast crops because of their importance in managing wildlife populations. In the past 30 years, we have begun to recognize the importance of masting in conserving and managing many other as
The effects of ENSO and the North American monsoon on mast seeding in two Rocky Mountain conifer species
We aimed to disentangle the patterns of synchronous and variable cone production (i.e. masting) and its relationship to climate in two conifer species native to dry forests of western North America. We used cone abscission scars to reconstruct ca 15 years of recent cone production in Pinus edulis and Pinus ponderosa, and used redundancy analysis to relate time series of annual cone production to c
The ecology and evolution of synchronized reproduction in long-lived plants
Populations of many long-lived plants exhibit spatially synchronized seed production that varies extensively over time, so that seed production in some years is much higher than on average, while in others, it is much lower or absent. This phenomenon termed masting or mast seeding has important consequences for plant reproductive success, ecosystem dynamics and plant–human interactions. Inspired b
Loss of branches due to winter storms could favor deciduousness in oaks
PremiseEcologists have an incomplete understanding of the factors that select for deciduous, evergreen, and marcescent leaf habits. Evergreens have more opportunities for photosynthesis but may experience costs when abiotic conditions are unfavorable such as during ice and windstorms.MethodsWe documented branch loss for species of oaks (Quercus spp.) in a common garden in California during an unus
Is there tree senescence? The fecundity evidence
Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small
Fine-scale plant defence variability increases top-down control of an herbivore
Herbivore populations are regulated by a combination of plant defences and natural enemies. While plant defence can suppress herbivore populations, these defences can also adversely affect natural enemies, thereby releasing herbivores from top-down control.Over their life spans, herbivores and their natural enemies may experience substantial variation in plant defence. Recent studies have demonstr
Long‐term surveys support declines in early‐season forest plants used by bumblebees
Populations of bumble bees and other pollinators have declined over the past several decades due to numerous threats, including habitat loss and degradation. However, we can rarely investigate the role of resource loss due to a lack of detailed long‐term records of forage plants and habitats.We use 22‐year repeated surveys of more than 262 sites located in grassland, forest, and wetland habitats a
Non-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/full
http://onlinelibrary.wiley.com/doi/10.1111/nph.14114/full
Mescher, 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/S136952661630098X
Krimmel, 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/full
Pesendorfer, 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/pdf
http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12554/pdf
Moriera, 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.0152537
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152537
Koenig, 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/full
Yguel, 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/10.1086/687964
Pearse, 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/ful
http://onlinelibrary.wiley.com/doi/10.1890/14-0297.1/ful
Koenig, 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/full
McMahon, 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_krJ9M
LoPresti, 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/full
http://onlinelibrary.wiley.com/doi/10.1890/15-0342.1/full
Pearse, 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/full
Pearse, 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/full
Pearse, 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/full
Pearse, 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.short
Desurmont, 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/S221457451400035
Krimmel, 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-z
Pearse, 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/full
Koenig, 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/full
Karban, 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.html
Pearse, 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/s00442-013-2779-4
Pearse, 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/s10886-012-0224-5
Pearse, 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/full
Pearse, 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/s00442-013-2610-2
Pearse, 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/full
Pearse, 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/full
Krimmel, 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/full
Savchenko, 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/10.1080/17429145.2013.765511
Pearse, 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/S0169204612002617
Pearse, 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.0038105
Pearse, 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/full
Altermatt, 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_contents
Joseph, 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/s10531-010-9956-0
http://link.springer.com/article/10.1007/s10531-010-9956-0
Pearse 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-z
Karban, 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/full
Pearse, 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
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/full
Pearse, 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
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
- Science
Developing a macroecological understanding of invasive plant impacts based on abundance and trait data
Understanding invasive plant impacts can provide insight into community assembly and inform the development of successful management strategies. The impacts of invasive species depend on how they alter patterns of abundance within recipient communities and on the characteristics of the invaders and the affected species. Research has suggested that common species may be more impacted by invasions, - Data
Filter Total Items: 17
INHABIT species potential distribution across the contiguous United States (ver. 3.0, January 2023)
We developed habitat suitability models for invasive plant species selected by Department of Interior land management agencies. We applied the modeling workflow developed in Young et al. 2020 to species not included in the original case studies. Our methodology balanced trade-offs between developing highly customized models for a few species versus fitting non-specific and generic models for numerData on how Lepidium draba responds to damage of clones
A greenhouse experiment was conducted to test the ability of the invasive clonal plant, Lepidium draba, to cope with damage to local and different ramets. The experiment was arranged in a fully factorial split-pot design that was blocked by bench position and provenance population of the plant. Plants were grown in 'split pots', where two adjoining pots were glued together with a small opening forData for a lab study of the effects of diet variability on the interactions between a Lepidopteran herbivore and its parasitoid
Data were collected from two laboratory rearing experiments conducted in 2018 of Trichoplusia ni caterpillars that had been parasitized by Copidosoma floridanum parasitoids. In the first experiment, parasitized caterpillars were fed artificial diets spiked with increasing concentrations of the phytochemical xanthotoxin in order to assess the effect of xanthotoxin on parasitoid success. In the secoGreenhouse observations of plant herbivore interactions on Lepidium draba to test effects of ontogenic variability
Data were collected from an experimental greenhouse study in which Lepidium draba plants were grown from root cuttings to create plants at different ontogenic stages. Plants were arranged in mixed-age and single-age stands and exposed to the Lepidopteran herbivore, diamondback moth caterpillars. The success (biomass gain and surivival) of herbivores, the amount of feeding, and the growth of plantsCalifornian crop pests, pesticide applications, and phylogenetic information of crops
Information on pesticide applications, crop pests, and phylogenetic affinities between Californian crops and regional native plants were compiled. Data was collected to inform models of pesticide applications and host use of pests among California's 93 major crops. Pesticide data was assembled from California Department of Pesticide Regulation records, pest information was assembled from the CalifData on the impacts of garlic mustard from a weeding experiment in Pennsylvania 2006-2016
Data were collected on the abundance of plants in a 10-year weeding experiment of garlic mustard, located at Trillium Trails Park in Pennsylvania. Garlic mustard was weeded annually to suppress its abundance, and the impacts of garlic mustard were measured based on the response of the plant community to garlic mustard weeding. Because garlic mustard is known to suppress mycorrhizal fungi, the mycoData on prairie dogs, plants, arthropod biomass, and birds for Thunder Basin, Wyoming in 2017
Data were collected in 2017 by researchers at the USGS, USDA-ARS, and University of Wyoming on the food webs of plants, prairie dogs, arthropods, and birds in the Thunder Basin National Grassland. Data were collected from 87 sites in order to parameterize a structural equation model linking prairie dog impacts to changes in vegetation, arthropods, and birds. Abiotic information such as topographicData on interannual seed set variation, weather, and reproductive traits for global plants
Data were collected on seed production dynamics of long-lived plants, reproductive plant traits of those plant species, and weather variability for sites where those species live. Data include the coefficient of variation in seed production over time, the variation (coefficient of variation or standard deviation) in weather over years, and reproductive traits such as pollination mode and seed dispData on cone production in pinyon pine in the Southwestern USA from 2003-2016
Data were collected on pinyon pine cone production using the cone scar method (Redmond et al 2016 Forest Ecology and Management) from 2003-2016 among sites in the Southwest USA. Long-term weather data (Vapor Pressure Deficits and monsoonality) were associated with cone scar data to assess weather-correlates of cone production.Data on gall wasp abundance and biomass on valley oak and blue oak trees in California
Gall abundance and biomass was recorded on marked valley oak and blue oak individuals throughout California. Galls, mostly caused by cynipid gall wasps, were identified to species. Sampling effort per tree was recorded as the number of leaves searched for gall wasps. Leaves were taken from two branches per tree using pole pruners, and total galls per tree were summed in each observation. Annual obLong term cone production of white spruce throughout boreal forests in North America
Data were compiled on the seed production of white spruce in order to assess the long-term trends in seed production over the past 60 years in North American boreal forests. Data on cone production was merged with annual weather, teleconnection indices such as ENSO, and historical fires in boreal forests.Data on interannual variability of seed production, nutrient, and weather for 219 plant species
We calculated estimates describing interannual variation in seed production for series of long-term seed or fruit production in 219 plant species. For each plant species, we compiled estimates of foliar nutrient concentrations as well as productivity and weather at the site of observation. Data was compiled in order to test whether interannual variation in seed production was greater in species wi - Publications
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Addressing detection uncertainty in Bombus affinis (Hymenoptera: Apidae) surveys can improve inferences made from monitoring
The U.S. Fish and Wildlife Service developed national guidelines to track species recovery of the endangered rusty patched bumble bee [Bombus affinis Cresson (Hymenoptera: Apidae)] and to investigate changes in species occupancy across space and time. As with other native bee monitoring efforts, managers have specifically acknowledged the need to address species detection uncertainty and determineHerbivory changes biomass allocation but does not induce resistance among clones of an invasive plant
Inducible responses to herbivores can be either localized or spread systemically throughout a plant. The ways in which clonal plants integrate their response to herbivores among clonal ramets is not well understood. Yet, this is important to understand the impacts that herbivores may have on clonal plants. We conducted a factorial split-plot greenhouse experiment to determine whether resistance isINHABIT: A web-based decision support tool for invasive plant species habitat visualization and assessment across the contiguous United States
Narrowing the communication and knowledge gap between producers and users of scientific data is a longstanding problem in ecological conservation and land management. Decision support tools (DSTs), including websites or interactive web applications, provide platforms that can help bridge this gap. DSTs can most effectively disseminate and translate research results when producers and users collaboThe importance of forests in bumble bee biology and conservation
Declines of many bumble bee species have raised concerns because of their importance as pollinators and potential harbingers of declines among other insect taxa. At present, bumble bee conservation is predominantly focused on midsummer flower restoration in open habitats. However, a growing body of evidence suggests that forests may play an important role in bumble bee life history. Compared withModes of climate variability bridge proximate and evolutionary mechanisms of masting
There is evidence that variable and synchronous reproduction in seed plants (masting) correlates to modes of climate variability, e.g. El Niño Southern Oscillation and North Atlantic Oscillation. In this perspective, we explore the breadth of knowledge on how climate modes control reproduction in major masting species throughout Earth's biomes. We posit that intrinsic properties of climate modes (Understanding mast seeding for conservation and land management
Masting, the intermittent and synchronous production of large seed crops, can have profound consequences for plant populations and the food webs that are built on their seeds. For centuries, people have recorded mast crops because of their importance in managing wildlife populations. In the past 30 years, we have begun to recognize the importance of masting in conserving and managing many other asThe effects of ENSO and the North American monsoon on mast seeding in two Rocky Mountain conifer species
We aimed to disentangle the patterns of synchronous and variable cone production (i.e. masting) and its relationship to climate in two conifer species native to dry forests of western North America. We used cone abscission scars to reconstruct ca 15 years of recent cone production in Pinus edulis and Pinus ponderosa, and used redundancy analysis to relate time series of annual cone production to cThe ecology and evolution of synchronized reproduction in long-lived plants
Populations of many long-lived plants exhibit spatially synchronized seed production that varies extensively over time, so that seed production in some years is much higher than on average, while in others, it is much lower or absent. This phenomenon termed masting or mast seeding has important consequences for plant reproductive success, ecosystem dynamics and plant–human interactions. Inspired bLoss of branches due to winter storms could favor deciduousness in oaks
PremiseEcologists have an incomplete understanding of the factors that select for deciduous, evergreen, and marcescent leaf habits. Evergreens have more opportunities for photosynthesis but may experience costs when abiotic conditions are unfavorable such as during ice and windstorms.MethodsWe documented branch loss for species of oaks (Quercus spp.) in a common garden in California during an unusIs there tree senescence? The fecundity evidence
Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of smallFine-scale plant defence variability increases top-down control of an herbivore
Herbivore populations are regulated by a combination of plant defences and natural enemies. While plant defence can suppress herbivore populations, these defences can also adversely affect natural enemies, thereby releasing herbivores from top-down control.Over their life spans, herbivores and their natural enemies may experience substantial variation in plant defence. Recent studies have demonstrLong‐term surveys support declines in early‐season forest plants used by bumblebees
Populations of bumble bees and other pollinators have declined over the past several decades due to numerous threats, including habitat loss and degradation. However, we can rarely investigate the role of resource loss due to a lack of detailed long‐term records of forage plants and habitats.We use 22‐year repeated surveys of more than 262 sites located in grassland, forest, and wetland habitats aNon-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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