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Ann K. Sakai

Professor, Ecology & Evolutionary Biology
School of Biological Sciences

PH.D., University of Michigan, 1978

Phone: (949) 824-6581
Fax: (949) 824-2181
Email: aksakai@uci.edu

University of California, Irvine
Ecology and Evolutionary Biology
321 Steinhaus Hall
Mail Code: 2525
Irvine, CA 92697

picture of Ann K. Sakai

plant population biology, plant breeding systems, conservation and restoration biology
URL Lab web page
Fellow, American Association for the Advancement of Science
William Evans Fellow, University of Otago (New Zealand) 2012
Botanical Society of America, Diversity Committee chair, 2011-2013
Celebration of Teaching-award for Teaching Excellence, School of Biological
Sciences, 2010
Society for the Study of Evolution, Council member 2004-2006
Chancellor’s Award for fostering undergraduate research 2002
Senior Mellon Fellow, Smithsonian Institution 1994
My research interests are in plant population biology and conservation biology, with a primary focus on the evolution of plant breeding systems. Most flowering plant species are hermaphroditic, but evolution of dioecy (separate male and female plants) has occurred independently in many lineages. I am interested in identifying the genetic and ecological factors that may promote the evolution of dioecy. I have examined these factors in the Hawaiian flora, a flora well known for its high incidence of endemism and dioecy. In collaboration with Stephen Weller, we have examined factors promoting the evolution of dioecy in Schiedea (Caryophyllaceae), a genus endemic to the Hawaiian Islands. Our work involves field studies of the pollination biology and ecology of populations in Hawaii, greenhouse studies of inbreeding depression and outcrossing levels, phylogenetic analyses, and studies of the genetic potential for changes in allocation patterns to male and female function through measurements of narrow sense heritabilities, genetic correlations, and with an artificial selection experiment. I am also interested in the evolution of heterostyly in the genus Oxalis, particularly the evolution of distyly from tristyly in Oxalis alpina.

My research interests also include conservation biology and restoration biology, particularly in the Hawaiian Islands. The native flora is disappearing at an alarming rate because of habitat destruction, introduction of alien invasive plants and herbivores, and changes in the climate. I am interested in both the invasiveness of particular species and the invasibility of native communities, and how knowledge of these processes can lead to better understanding and management of alien invasive species and protection of the native flora.
Publications Weisenberger, L. A., S. G. Weller, and A. K. Sakai. 2014. Remnants of populations provide effective source material for reintroduction of an endangered Hawaiian plant, Schiedea kaalae Caryophyllaceae). American Journal of Botany 101:1954-1962.
  Weller, S. G., A. K. Sakai, T. M. Culley, L. Duong, and R. E. Danielson. 2014. Segregation of male sterility alleles across a species boundary. Journal of Evolutionary Biology 27: 429-436.
  Sakai, A. K., S. G. Weller, D. R. Campbell, T. M. Culley, A. K. Dunbar-Wallis, and A. M. Andres. 2013. Measure for measure: comparing morphological and biomass traits for sex allocation in two gynodioecious species. American J. Botany. 100(6): 1071-1082.
  Weller, S. G., K. Suding, and A. K. Sakai. 2013. Botany and a changing world: introduction to the special issue on global biological change. American J. Botany. 100(7):1229-1233.
  Weber, J. J., S. G. Weller, A. K. Sakai, L.-Q. Nguyen, and D. Khuu. 2013. Breeding system evolution in Oxalis alpina: asymmetrical expression of tristylous incompatibility. International J. Plant Sciences. 174:179-188.
  Weber, J. J., S. G. Weller, A. K. Sakai, O. V. Tsyusko, T. C. Glenn, C. A. Dominguez, F. E. Molina-Freaner, J. Fornoni, M. Tran, N. Nguyen, K. Nguyen, L-K Tran, G. Joice, and E. Harding. 2013. The role of inbreeding depression and mating system in the evolution of heterostyly. Evolution 67: 2309-2322.
  Weber, J. J., S.G. Weller, A.K. Sakai, A. Nguyen, N.D. Tai, C.A. Dominguez, and F.E. Molina-Freaner. 2012. Purging of inbreeding depression within a population of Oxalis alpina (Oxalidaceae). American J. Botany 99:923-932.
  Jürgens, A., M. Bischoff, A.K. Sakai, S.G. Weller. 2012. Floral scent of four Hawaiian Schiedea species (Caryophyllaceae). Biochemical Systematics and Ecology. 45: 194-197.
  Vary, LB, DL Gillen, M Randrianjanahary, PP Lowry II, AK. Sakai, and SG. Weller. 2011. Dioecy, monoecy, and their ecological correlates in the littoral forest of Madagascar. Biotropica. 43: 582-590.
  Kutaka, JJ, SG Weller, CA Dominguez, AK Sakai, FE Molina-Freaner, P Sosenski, and J Fornoni. 2011. Female and male mediation of incompatibility modifications during the tristyly-distyly transition in Oxalis alpina. International J. Plant Sciences. 172:644-654.
  Vary LB, Sakai AK, Weller SG. 2011. Morphological and functional sex expression in the Malagasy endemic Tina striata (Sapindaceae). American J. Botany 98(6):1040-8.
  Wallace LE, Culley TM, Weller SG, Sakai AK, Kuenzi A, Roy T, Wagner WL, Nepokroeff M. 2011. Asymmetrical gene flow in a hybrid zone of Hawaiian Schiedea (Caryophyllaceae) species with contrasting mating systems. PLoS One 6(9):e24845
  Campbell DR, Weller SG, Sakai AK, Culley TM, Dang PN, Dunbar-Wallis AK. 2011. Genetic variation and covariation in floral allocation of two species of Schiedea with contrasting levels of sexual dimorphism. Evolution 65(3):757-70.
  Willyard A, Wallace LE, Wagner WL, Weller SG, Sakai AK, Nepokroeff M. 2011. Estimating the species tree for Hawaiian Schiedea (Caryophyllaceae) from multiple loci in the presence of reticulate evolution. Mol Phylogenet Evol.
  Weller, SG., RJ Cabin, DH Lorence, S Perlman, K Wood, T Flynn, and AK Sakai. 2011. Alien plant invasions, introduced ungulates, and alternative states in a mesic forest in Hawaii. Restoration Ecology 19: 671-680.
  Caujapé-Castells, J., K. Beaver, D. J. Crawford, F. B. Vincent Florens, I. Gómes, R. Jardim, W. Lobin, M. Moura, A. Sakai, A. Santos-Guerra, A. Tye, C. Kueffer. 2010. Conservation of oceanic island floras: present and future global challenges. Perspectives in Plant Ecology, Evolution and Systematics 12:107-129.
  Wallace, L. E., S. G. Weller, W. L. Wagner, A. K. Sakai, and M. Nepokroeff. 2009. Phylogeographic patterns and demographic history of Schiedea globosa (Caryophyllaceae) on the Hawaiian Islands. American Journal of Botany 96: 958-967.
  Culley, T. M., S. G. Weller, A. K. Sakai, and K. Putnam. 2008. Characterization of microsatellite loci in the Hawaiian endemic shrub, Schiedea adamantis (Caryophyllaceae) and amplification in related species and genera. Molecular Ecology Resources (formerly Molecular Ecology Notes). 8: 1081-1084.
  Sakai, A. K., S. G. Weller , T. M. Culley, D. R. Campbell, A. K. Dunbar-Wallis, and A. Andres. 2008. Sexual dimorphism and the genetic potential for evolution of sex allocation in the gynodioecious plant, Schiedea salicaria. Journal of Evolutionary Biology 21:18-29.
  Poulin, J., A. K. Sakai, S. G. Weller, and T. Nguyen. 2007. Phenotypic plasticity, precipitation, and invasiveness in the fire-promoting grass, Pennisetum setaceum (Poaceae). American Journal of Botany. 94:533-541.
  Weller, S. G., A. K. Sakai, T. M. Culley, D. R. Campbell, P. Ngo, and A. K. Dunbar-Wallis. 2007. Sexually dimorphic inflorescence traits in a wind-pollinated species: heritabilities and genetic correlations in Schiedea adamantis (Caryophyllaceae). American Journal of Botany 94:1716-1725.
  Weller, S. G., A. K. Sakai, D. R. Campbell, T. M. Culley, and A. Dunbar-Wallis. 2006. Predicting the pathway to wind pollination: heritabilities and genetic correlations of inflorescence traits associated with wind pollination in Schiedea salicaria (Caryophyllaceae). Journal of Evolutionary Biology 19: 331-342.
  Sakai, A. K., S. G. Weller, W. L. Wagner, M. Nepokroeff, and T. M. Culley. 2006. Adaptive radiation and evolution of breeding systems in Schiedea (Caryophyllaceae), an endemic Hawaiian genus. Annals of the Missouri Botanical Garden. 93: 49-63.
  Culley, T. M., A. K. Dunbar-Wallis, A. K. Sakai, S. G. Weller, and D. R. Campbell. 2006. Genetic variation of ecophysiological traits in two gynodioecious species of Schiedea (Caryophyllaceae). New Phytologist. 169: 589-601.
  Golonka, A. M. , A. K. Sakai, and S. G. Weller. 2005. Wind pollination, sexual dimorphism, and changes in floral traits of Schiedea (Caryophyllaceae). American Journal of Botany 92:1492-1502.
  Weller, S. G., A. K. Sakai, D. A. Thai, J. Tom, and A. E. Rankin. 2005. Inbreeding depression and heterosis in populations of Schiedea viscosa, a highly selfing species. Journal of Evolutionary Biology 18:1434-1444.
  Culley, T. M., A. K. Dunbar-Wallis, A. K. Sakai, S. G. Weller, and D. R. Campbell. 2005. Genetic variation in ecophysiological traits and the evolution of gynodioecy in Schiedea (Caryophyllaceae). New Phytologist 169: 589-601.
  Poulin J., S. G. Weller, A. K. Sakai. 2005. Genetic diversity does not affect the invasiveness of fountain grass (Pennisetum setaceum) in Arizona, California and Hawaii. Diversity and Distributions 11: 241-247.
  Weller, S. G., and A. K. Sakai. 2005. Selfing and resource allocation in Schiedea salicaria (Caryophyllaceae), a gynodioecious species. Journal of Evolutionary Biology 18:301-308.
  Wagner, W. L., S. G. Weller, and A. K. Sakai. 2005. Monograph of Schiedea (Caryophyllaceae subfam. Alsinoideae). Systematic Botany Monographs 72: 1-169.
  Weller, S. G., A. K. Sakai, D. R. Campbell, T. M. Culley, and A. Dunbar-Wallis. 2005. Predicting the pathway to wind pollination: heritabilities and genetic correlations of inflorescence traits associated with wind pollination in Schiedea salicaria (Caryophyllaceae). Journal of Evolutionary Biology. 19: 331-342.
  Rankin, A. E., S. G. Weller, and A. K. Sakai. 2002. Mating system instability in Schiedea menziesii (Caryophyllaceae). Evolution 56: 1574-1585.
  Sakai, A. K., W. L. Wagner, and L. Mehrhoff. 2002. Patterns of endangerment in the Hawaiian flora. Systematic Biology 51: 276-302.
  Sakai, A. K., F. W. Allendorf, J. S. Holt, D. M. Lodge, J. Molofsky, K. A. With, S. Baughman, R. J. Cabin, J. E. Cohen, N. C. Ellstrand, D. E. McCauley, P. O'Neil, I. M. Parker, J. N. Thompson, and S. G. Weller. 2001. The Population Biology of Invasive Species. Annual Review of Ecology and Systematics 32: 305-332.
  Culley TM, Weller SG, Sakai AK, Rankin AE. 1999. Inbreeding depression and selfing rates in a self-compatible, hermaphroditic species, Schiedea membranacea (Caryophyllaceae). Am J Bot. 86(7):980-7.
  Weller, S. G., A. K. Sakai, A. E. Rankin, A. Golonka, B. Kutcher, and K. E. Ashby. 1998. Dioecy and the evolution of wind pollination in Schiedea and Alsinidendron (Caryophyllaceae: Alsinoideae) in the Hawaiian Islands. American Journal of Botany 85:1377-1388.
  Sakai, A. K., S. G. Weller, M.-L. Chen, S.-Y. Chou, and C. Tasanont. 1997. Evolution of gynodioecy and maintenance of females: the role of inbreeding depression, outcrossing rates, and resource allocation in Schiedea adamantis (Caryophyllaceae). Evolution 51:724-736.
  Sakai, A. K. and M. J. Lane. 1996. National Science Foundation funding patterns of women and minorities in biology. BioScience 46: 621-625.
  Goldberg, D. and A. K. Sakai. 1993. Career options for dual-career couples: results of an ESA survey on soft money research positions and shared positions. Bulletin of the Ecological Society of America. 74:146-152.
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Last updated 12/08/2014