Dr. Randy Mitchell
Office: ASEC E513
Raised in the Central Valley of California on a walnut ranch near the Sierras, I grew up loving science, the outdoors, backpacking, and insects. In High School I was told that ‘they know everything about biology,’ so I was amazed in College when I learned how wrong that statement was. As H.E. Evans says, “We live on a ‘little known planet.” And when I found out that you can do science outdoors, there was no doubt about what I would do. I have been fortunate to have done research (and enjoyed the outdoors) in many wonderful places, including Colorado’s Rocky Mountain Biological Laboratory, California’s deserts and mountains and scrub, Adelaide Australia, New Mexico’s mountains and deserts, Wisconsin’s wetlands, and the wonderful Cuyahoga Valley. With my family (wife Karen and daughters Ellen and Natalie) I continue to revel in nature and biology, with frequent hiking, biking, orienteering, and gardening.
My main research interest is in the evolutionary ecology of plant pollinator interactions, focusing on how plant mating patterns and success are affected by pollinator behavior and abundance. This work utilizes a broad array of field, genetic, statistical, histological, horticultural, imaging, and modeling approaches, drawing from many disciplines in and out of biology. Some of my projects have direct or indirect implications for conservation efforts and management of endangered or invasive species. My current projects focus on mating systems in a native wildflower (in collaboration with Jeff Karron at University of Wisconsin Milwaukee), and on bumble bee conservation. I have a growing interest in wetland ecology and restoration ecology.
Postdoc 1994 University of New Mexico..
PhD 1991 University of California Riverside
Visiting Student 1985 University of Adelaide, South Australia.
MA 1987 University of California Riverside.
BS 1982 University of California, Davis. Entomology.
Jr College 1979 College of Sequoias, Visalia, California.
High School 1978 Tulare Union High School, California
2021. Christopher DA, Karron JD, Semski WR, Smallwood PA, Trapnell DW, Mitchell RJ. Selfing rates vary with floral display, pollinator visitation and plant density in natural populations of Mimulus ringens. Journal of Evolutionary Biology. 34:803–815
2021. Novotny, JL, P Reeher, M Varvaro, A Lybbert, J Smith, RJ Mitchell, and K Goodell. Bumble bee species distributions and habitat associations in the Midwestern USA, a region of declining diversity. Biodiversity and Conservation 30:865-887.
2020. Christopher, DA, RJ Mitchell, DW Trapnell, PA Smallwood, WR Semski, and JD Karron. Edge effects and mating patterns in a bumblebee-pollinated plant. AoB Plants 12:plaa033
2020. Reeher, P, J Lanterman Novotny, RJ Mitchell. Urban bumble bees are unaffected by the proportion of intensely developed land within urban environments of the industrial Midwestern USA. Urban Ecosystems. 23(4): 703-711.
2020. Stotz, GC, JA Cahill Jr. JA Bennett, CN Carlyle, EW Bork, D Askarizadeh, S Bartha, C Beirkuhnlein, B Boldgiv, L Brown, M Cabida, G Camptella, S Chelli, O Cohen, S Diaz, L Enrico, D Ensing, B Erdentsetseg, A Fidelis, HW Garris, HAL Henry, A Jentsch, MH Jouri, K Koorem P Manning, RJ Mitchell, M Moora, GE Overbeck, J Pither, KO Reinhart, M Sternberg, R Tungalg, S Undrakhbold, M van Rooyen, C Wellstein, M Zobel, LH Fraser. Not a melting pot: alien species aggregate in their introduced range. Global Ecology and Biogeography.9(3): 482-490.
2020. Christopher, DA, RJ Mitchell, JD Karron. Pollination intensity and paternity in flowering plants. Annals of Botany 125:1-9
2020. Ramlo, S, D Starvaggi, RJ Mitchell, and L Roketenetz. Developing Concourse and Selecting a Q Sample: Preparation for a Q study About Urban, American, Middle-School Science Students’ Views of Nature. Operant Subjectivity 41:110-120.
2019 Lanterman, J, P Reeher, RJ Mitchell, K Goodell. Habitat preference and phenology of nest seeking and foraging spring bumble bee queens in northeastern North America (Hymenoptera: Apidae: Bombus). The American Midland Naturalist 182:131-159.
2019. Christopher DA, Mitchell RJ, Trapnell DW, Smallwood PA, Semski WR, Karron JD. Hermaphroditism promotes mate diversity in flowering plants. American Journal of Botany. 106:1131-6.
2018. Miller, T and RJ Mitchell. Source locality effects on restoration potential in Sphagnum palustre L. from three Ohio sites. The Ohio Journal of Science 118: 34-42.
2018. Whitehead, MR, R Lanfear, RJ Mitchell, JD Karron. Plant mating systems often vary widely among populations. Frontiers in Ecology and Evolution 6: 38.
2017. Hallett, AC., RJ Mitchell, ER Chamberlain, and JD Karron. Pollination success following loss of a frequent pollinator: the role of compensatory visitation by other effective pollinators. AoB Plants 9:plx020-plx020.
2016. Sorin, YB, RJ Mitchell, DW Trapnell,, JD Karron. Effects of pollination and postpollination processes on selfing rate in Mimulus ringens. American Journal of Botany. 103: 1524-1528.
2015. Fraser, L H, J Pither, A Jentsch, M Sternberg, M Zobel, D Askarizadeh, S Bartha, C Beierkuhnlein, J A Bennett, A Bittel, B Boldgiv, II Boldrini, E Bork, L Brown, M Cabido, J Cahill, C N Carlyle, G Campetella, S Chelli, O Cohen, A-M Csergo, S Díaz, L Enrico, D Ensing, A Fidelis, J D Fridley, B Foster, H Garris, J R Goheen, H A L Henry, M Hohn, M H Jouri, J Klironomos, K Koorem, R Lawrence-Lodge, R Long, P Manning, RJ Mitchell, M Moora, S C Müller, C Nabinger, K Naseri, G E Overbeck, T M Palmer, S Parsons, M Pesek, V D Pillar, R M Pringle, K Roccaforte, A Schmidt, Z Shang, R Stahlmann, G C Stotz, S-i Sugiyama, S Szentes, D Thompson, R Tungalag, S Undrakhbold, M van Rooyen, C Wellstein, J B Wilson, and T Zupo. Worldwide evidence of a unimodal relationship between productivity and plant species richness. Science 349:302-305.
2014. Garris, HW, RJ Mitchell, LH Fraser, and LR Barrett. Forecasting climate change impacts on the distribution of wetland habitat in the Midwestern United States. Global Change Biology. 21: 766-776.
2013. Mitchell, RJ, WG Wilson, KG Holmquist, JD Karron. Mating patterns and sire profiles in flowering plants: exploring the effects of pollinator behavior and pollen carryover. PLoSONE 8(10):e76312 doi:10.1371/journal.pone.0076312
2012. Karron, JD, RJ Mitchell. Effects of floral display size on male and female reproductive success in Mimulus ringens. Annals of Botany . doi:10.1093/aob/mcr193
2012.Karron, JD, CT Ivey, RJ Mitchell, MR Whitehead, R Peakall, AL Case. Viewpoint: New perspectives on the evolution of plant mating systems. Annals of Botany doi:10.1093/aob/mcr319.
2012. Holmquist KG, Mitchell RJ, Karron JD. 2011. Influence of pollinator grooming on pollen-mediated gene dispersal in Mimulus ringens (Phrymaceae). Plant Species Biology: no-no. DOI: 10.1111/j.1442-1984.2011.00329.x
2011. Pan, JJ, D Ammerman, RJ Mitchell. Nutrient amendments in a temperate grassland have negative impacts on early season and exotic plant species. Plant Ecology 212:853-864
2011. Flanagan, RJ, RJ Mitchell, JD Karron. Effects of multiple competitors for pollination on bumblebee foraging patterns and Mimulus ringens reproductive success. Oikos 120: 200–207.
2010. Flanagan, RJ, RJ Mitchell, and J. Karron. Increased relative abundance of an invasive competitor for pollination, Lythrum salicaria, reduces seed number in Mimulus ringens. Oecologia 164:445-454.
2009. Mitchell, RJ, RJ Flanagan, BJ Brown, NM Waser, JD Karron. New frontiers in competition for pollination. Annals of Botany 103:1403-1413.
2009. Mitchell RJ, Irwin RE, Flanagan RJ Karron JD. Viewpoint: Ecology and evolution of plant-pollinator interactions. Annals of Botany 103:1355-1363
2009. Karron, JD, KG Holmquist, RJ Flanagan, RJ Mitchell. Pollinator visitation patterns strongly influence among-flower variation in selfing rate. Annals of Botany 103:1379-1383.
2009. Burd, M., TL Ashman, DR Campbell, MR Dudash, MO Johnston, TM Knight, SJ Mazer, R J Mitchell, J A. Steets, JC Vamosi. Ovule number per flower in a world of unpredictable pollination. American Journal of Botany 96:1159-1167
2009. Flanagan, R. J., R. J. Mitchell, D. Knutowski, and J. D. Karron. Interspecific pollinator movements reduce pollen deposition and seed production in Mimulus ringens (Phrymaceae). American Journal of Botany 96:809-815.
2008. Bernhardt CE, RJ Mitchell, HJ Michaels. Effects of population size and density on pollinator visitation, pollinator behavior, and pollen tube abundance in Lupinus perennis. International Journal of Plant Sciences 169: 944-953.
2008. Michaels HJ, XJ Shi, RJ Mitchell. Effects of population size on performance and inbreeding depression in Lupinus perennis. Oecologia 154:651-661.