Biography Education Academic Positions Present Research Memberships Grants Received Publications Back to Faculty

Stephen Mulkey, Ph.D.

Associate Professor of Botany

• Tropical Ecology
• 422 Carr Hall
• (352) 392-2775 (Voice)
• (352) 392-3993 (Fax)
• mulkey@botany.ufl.edu

Biography

I am an evolutionary ecologist with specialization on Neotropical plants. Specifically, I use physiological and functional morphological responses of plants in variable environments to understand plant distribution and abundance. Since 1980, I have worked in Eastern Africa, Latin America, and Malaysia. My research program uses large, industrial cranes to access the canopy of tropical forest. I enjoy backpacking, natural history, and acoustic folk music.

Education

• B.S. Forestry, Fisheries and Wildlife. The University of Missouri. 1975.
• M.A. Biology, Ecology. The University of Missouri. 1979.
• Ph.D. Biology, Ecology. The University of Pennsylvania. 1986.
• M.S. Title: Avian communities of habitat islands in south-central Canada.
• Ph.D. Title: Physiological ecology and demography of three species of Neotropical herbaceous bamboos (Gramineae).

Academic Positions

• 2005- present: Director Research and Outreach/Extension, School of Natural Resources and Environment, University of Florida
• 2001-present: Research Associaste, School of Forest Resources and Conservation, The University of Florida
• 1997-present: Associate Professor of Botany, The University of Florida
• 1997-2002: Research Associate, Smithsonian Institution, Tropical Research Institute
• 1996-1997: Director, International Center for Tropical Ecology
• 1995-1996: Associate Director, International Center for Tropical Ecology.
• 1994-1997: Research Affiliate. Smithsonian Tropical Research Institute.
• 1993-1997: Associate Professor of Biology, University of Missouri at St. Louis.
• 1990-1991: Visiting Assistant Professor, Botany Department, University of California, Davis.
• 1986-present: Research Associate, Missouri Botanical Garden.
• 1986-1993: Assistant Professor of Biology, University of Missouri at St. Louis.

Research Interests / Major Research Achievements:

• Regrowth forests in Amazonia
• Canopy carbon budgets and gas exchange in tropical forests.
• Phenotypic plasticity in suites of functional characters as influenced by temporal and spatial variability in resource availability in understory and canopy tropical forest plants.
• Relationship of physiology to the distribution and abundance of plant species and genotypes with emphasis on microsite adaptation.
• Use of WWW and computer networks for graduate and undergraduate education

Present Research

Recently there has been considerable interest in the determinants of tropical forest productivity. Our data from observing the changes in leaf characteristics between the wet season and the dry season suggest that rainforests are limited by available sunlight during the cloudy, rainy season. Presently, we are testing this hypothesis using the canopy cranes in Panama in conjunction with light augmentation experiments.

Present Students

• Jason Hupp. M.S.
• Amethyst Merchant. Ph.D.
• James Watkins. Ph.D.

Past Students

• Pedro Lopez-Valencia. M.S. December 1993. Conservation Fellow and GIS systems Administrator at World Wildlife Fund-US. 1994. Presently Technical Subdirector for Ecosystems, National Institute of Environmental Studies (IDEAM) of the Republic of Colombia.
• Deborah Olander, M.S. August, 1996. Presently PhD student at U. of Minnesota.
• Gerardo Avalos. Ph.D. 1999. Presently an Assistant Professor at the U. of Costa Rica
• Hillary Cherry, MS 2002.
• Lisa Merry, MS 2002.
• Grace Crummer, MS 2003.
• Louis Santiago. Ph.D. 2003.
• Juan Posada. Ph.D. 2003

Past Post-doctoral Associates

• Dr. Eric Graham, Ph.D.
• Juan Posada, Ph.D.

Courses Taught:

• PCB 3043 Introductory Ecology (login: student / password: ecology)
• BOT 5655 Advanced Physiological Plant Ecology (login: student / password: ecology)
  
• Link to Mulkey web sites

Membership in Professional Organizations:

• Association for Tropical Biology
• Botanical Society of America
• Ecological Society of America
• International Canopy Network
• International Canopy Crane Network (co-founder)
• Sigma Xi

Grants received

Since 1993 my work has been supported by four grants from NSF, two grants from the University of Missouri, with additional support from the Smithsonian Institution and the Andrew Mellon Foundation.

• 2000-2004. Characteristics of regrowth forest in Eastern Amazonia. The Andrew Mellon Foundation $480,000 with Dan Zarin.
• 1998-1999. NSF. Branch carbon balance and allocation during an extreme El Niño and La Niña in a wet neotropical forest. $50,000.
• 1998-1999. Andrew Mellon Foundation. Carbon balance in the canopies of two neotropical forests with contrasting seasonality. $140,000.
• 1998. CLAS instrumentation award. $28,000 (with K. Kitajima).
• 1997. UM Research Board. Functional convergence in two neotropical forests. $28,000.
• 1995-1997. NSF. Bioinstrumentation (BIR-9419994). Plant physiology and plant ecology. $206,500.
• 1995-1997. Research award. UM-St. Louis. Regional carbon flux in two Neotropical forests. $9,800.
• 1994. NSF. Functional and Integrative Biology Research Opportunity Award Elizabeth Newell Co-PI. Phenology of nonstructural carbohydryate flux in a tropical canopy. $11,000.
• 1993-1997. NSF Functional and Integrative Biology (IBN-9220759). Variation in resource availability and consequences for interdependent physiological and morphological leaf traits in two Neotropical canopy tree species. $188,866.

Selected Publications

Gamon, J. A., S. S. Mulkey, and K. Kitajima. 2005. Diverse optical and photosynthetic properties in a neotropical forest during the dry season: implications for remote estimation of photosynthesis. Biotropica In Press.

Avalos, G. and S. S. Mulkey 2005. Photochemical efficiency of adult and young leaves of the neotropical understory shrub Psychotria limonensis (Rubiaceae) in response to changes in the light environment. Biotropica In Press.

Aragão, D. V., L. B. Fortini, and S. S. Mulkey. 2005. The role of drought and reproduction in gas exchange in an understory tropical plant Miconia ciliata (Melastomataceae): correlation but no causation between leaf nitrogen and maximum assimilation. American Journal of Botany 92:456-461.

Santiago, L. S. and S. S. Mulkey. 2005. Leaf productivity along a precipitation gradient in lowland Panama: patterns from leaf to ecosystem. Trees - Structure and Function 19:349-356.

Kitajima, K. Mulkey, S. S., and Wright, S. J. 2005. Variation in crown light utilization characteristics among tropical canopy trees. Annals of Botany 95(2) 1-13.

Santiago, L. S., Mulkey, S. S. 2003. A test of gas exchange measurements on excised canopy branches of ten tropical tree species. Photosynthetica In Press .

Fortini, L., Mulkey, S. S., Zarin, D. J., Vasconcelos, S. S., Carvalho, de C. J. R. 2003. Drought constraints on leaf gas exchange by Miconia ciliata (Melastomataceae) in the understory of an Eastern Amazonian regrowth forest stand. American Journal of Botany 90:1064-1070.

Graham, E. A., Mulkey, S. S., Wright, S. J., Kitajima, K. and Phillips, N. G. 2003. Cloud cover limits productivity in a tropical rain forest tree during La Nina. Proceedings of the National Academy of Science : 572-576.

Kitajima, K., Mulkey, S. S., Samaniego, M., and Wright, S. J. 2002. Decline of photosynthetic capacity with leaf age and position in two tropical pioneer tree species. American Journal of Botany 89: 1925-1932.

Terwilliger, V., Kitajima, K., Le Roux-Swarthout, D. J., Mulkey, S. S. Wright, S. J. 2001. Influences of heterotrophic and autotrophic resource use on carbon and hydrogen isotopic copositions of tropical tree leaves. Isotopes in Environmental and Health Studies 2001 , Vol 37:133-160.

Terwilliger, V. J., Kitajima, K., Le Roux-Swarthout, D. J., Mulkey, S. Wright, S. J. 2001. Intrinsic water-use efficiency and heterotropic investment in tropical leaf growth of two Neotropical pioneer tree species as estimated from delta 13-C values. New Phytologist 152:267-281.

Avalos, G. and S. S. Mulkey. 1999. Photosynthetic acclimation of the liana Stigmaphyllon lindenianum to light changes in a tropical dry forest canopy. Oecologia 120:475-484.

Avalos, G. and S.S. Mulkey. 1999. Seasonal changes in liana cover in the upper canopy of a neotropical dry forest. Biotropica 31:186-192.

Avalos, G., S. S. Mulkey, and S. J. Wright. Contribution of lianas to the photosynthetic surface of the outer canopy in a tropical dry forest. In Press. Biotropica.

Avalos, G. S. S. Mulkey, and K.Kitajima. 1999. Optical properties of tree and liana foliage in the canopy of a tropical dry forest. Biotropica 31:517-520.

Stork, N.E., S.J. Wright, and S.S. Mulkey. 1997. Craning for a better view: the Canopy Crane Network. Trends in Ecology and Ecolution 12:418-419.

Mulkey, S.S. (Invited review) 1997. The ecology of a tropical forest: seasonal rhythms and long-term changes. Second Edition. Leigh et al. (Eds). Quarterly Review of Biology 72:488.

Kitajima, K. S. S. Mulkey, and S. J. Wright. 1997. Seasonal leaf phenotypes in the canopy of a tropical dry forest: photosynthetic characteristics and associated traits. Oecologia 109:490-498.

Kitajima, K. S. S. Mulkey, and S. J. Wright. 1997. Decline of photosynthetic capacity with leaf age and leaf longevities for five tropical canopy tree species. American J. Botany 84:702-708.

Mulkey, S. S., K. Kitajima, and S. J. Wright. 1996. Plant physiological ecology of tropical forest canopies. Trends in Ecology and Evolution 11:408-412.

Mulkey, S. S., R. L. Chazdon, A. P. Smith (Editors). 1996. Tropical Forest Plant Ecophysiology. Chapman and Hall. NY

Mulkey, S. S., S. J. Wright, and A. P. Smith. 1996. Influence of seasonal drought on the carbon balance of tropical forest plants. In: S. S. Mulkey, R. Chazdon, A. P. Smith (eds.) Tropical Forest Plant Ecophysiology. Chapman and Hall. NY.

Mulkey, S. S., S. J. Wright, K. Kitajima. 1995. Photosynthetic capacity and leaf longevity in the canopy of a dry tropical forest. Selbyana 16:169-173.

Mulkey, S. S., S. J. Wright, and A. P. Smith. 1993. Comparative physiology and demography of three Neotropical forest shrubs: alternative shade-adaptive character syndromes. Oecologia 96:526-536.

Wright, S. J., J. L. Machado, S. S. Mulkey, and A. P. Smith. 1992. The water relations of understory shrubs (Psychotria Rubiaceae) in a tropical moist forest. Oecologia 89:457-463.

Mulkey, S. S., A. P. Smith, S. J. Wright, J. L. Machado, and R. Dudley. 1992. Contrasting leaf phenotypes control seasonal variation in water loss in a tropical forest shrub. Proceedings of the National Academy of Sciences (USA) 89:9084-9088.

Mulkey, S. S., and R. W. Pearcy. 1992. Interactions between acclimation and photoinhibition of photosynthesis of a tropical forest understory herb, Alocasia macrorrhiza (L.) G. Don, during simulated canopy gap formation. unctional Ecology 6:719-729.

Mulkey, S. S., A. P. Smith, and S. J. Wright. 1991a. Comparative life history and physiology of two understory Neotropical herbs. Oecologia 88: 263-273.

Mulkey, S. S., S. J. Wright, and A. P. Smith. 1991b. Drought acclimation of an understory shrub in a seasonally dry tropical forest. American Journal of Botany 78: 579-587.

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