Todd E. Dawson

Professor - Departments of Integrative Biology (primary) and Environmental Science, Policy & Management

Director – Center for Stable Isotope Biogeochemistry: (510) 643-1748


Faculty Director - Blue Oak Ranch Reserve


Office: 4006 Valley Life Sciences Building

Office telephone: (510) 642-6090

Lab telephone: (510) 642-1054


Research Interests

As noted at the beginning of my lab group’s home page our research is focused on the interface between plants and their environments with a special emphasis placed on exploring this interface from a functional perspective.  Research projects therefore apply the tools from physiological and evolutionary plant ecology, ecosystem science, stable isotope biogeochemistry and remote sensing and modeling towards the study and interpretation of the plant-environment interface.  We work across an array of study systems, scales, organisms, and questions that draw upon a variety of empirical and theoretical methods. These are merged with the application of diverse approaches (observations, monitoring, and experimental manipulations) as avenues for improving our understanding of how the ecophysiological characteristics of plants are shaped by and respond to the environments they inhabit. 

The projects I lead or participate in pay special attention to how aspects of plant form and function combine to permit adaptation to environmental variation, whether naturally or anthropogenically imposed, and how plants and their unique traits influence the structure and function of the communities and ecosystems they compose or that they have membership with. Recently, many projects have been structured around global climate and land-use changes as the foundational rationale for the studies we undertake but our goals are to always make sure to are working on fundamental biological features.

Besides working with the students and postdocs in the group on the projects they lead, my own research time is split between several collaborative investigations. These ongoing investigations are focused on questions or hypotheses directed towards the key organisms themselves (e.g., redwoods, oaks), the communities or ecosystem processes that these organisms impact (e.g., hydrological ["Hydrowatch"; see, biogeochemical), or broad themes that form the foundation of the field of science I have and continue to work in (e.g., the functional basis of adaptation, “ecosystem physiology” or the roles of plants in higher order processes, how and why ecophysiology shapes species distribution, etc.). Currently, field research in California, Mexico and South Africa occupy my thoughts and time. In the laboratory I continue to be keenly interested in pushing technology development that is central to helping us answer our questions and test our hypotheses. This aspect of my research is also very much collaborative and crosses the fields of chemistry (working on new stable isotopes methods and instruments), computer science and engineering (working with wireless sensor networks in an environmental context), and remote sensing (working with satellite-based images and data and other remotely sensed information like LiDAR).

I teach four principle (core) courses, two that alternate in the spring term (in odd years, Physiological Plant Ecology [IB 151/151L] and in even years, Stable Isotope Biogeochemistry [IB c227/ESPM c220 co-taught with Ron Amundson and Stefania Mambelli), one that I teach every fall semester (Training in Stable Isotope Methods and Mass Spectrometry [IB 400] with Paul Brooks) and one graduate discussion group that I co-teach every fall with Stefania Mambelli (“Isotopics” [IB c226/ESPM c225).  I am also regularly involved in three other minor / occasional courses; “Ecolunch” [IB 251] that is co-lead by IB ecology faculty every semester, occasional “special topic” graduate seminars [IB 250] and nearly every semester I supervise one or more undergraduate research course credits [“199”].

Publications since 2005 [books and book chapters are in red]

Kahmen, A., K.S. Simonin, K.P. Tu, G. Goldsmith and T.E. Dawson. 2009. The influence of species and growing conditions on oxygen isotope leaf water enrichment and its impact on “effective path length”. New Phytologist 184 (3): 619-630.

Limm, E.B., K.A. Simonin, A.G. Bothman and T.E. Dawson. 2009. Foliar water uptake: a common water acquisition strategy for plants of the redwood forest. Oecologia 161: 449-459. 

Craine, J.M., A.J. Elmore, M. P.M. Aidar, M. Bustamante, T.E. Dawson, E.A. Hobbie, A. Kahmen, M.C. Mack, K.K. McLauchlan, A. Michelsen, G.B. Nardoto, L.H. Pardo, J. Peñuelas, P.B. Reich, E.A.G. Schuur, W.D. Stock, P.H. Templer, R.A. Virginia, J.M. Welker, and I.J. Wright. 2009. Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability. New Phytologist 183: 980-99.

Simonin, K.S., L.S. Santiago and T.E. Dawson. 2009. Fog interception by Sequoia sempervirens (D. Don) crowns decouples physiology from soil water deficit. Plant, Cell & Environment 32: 882-892. 

Ambrose, A.R., S.C. Sillett and T.E. Dawson. 2009. Effects of tree height on branch hydraulics, leaf structure, and gas exchange in California’s redwood species. Plant, Cell & Environment 32: 743-757.

Moriarty, K.M., W.J. Zielinski, A.G. Gonzales, T.E. Dawson, K.M. Boatner, C.A. Wilson, F.V. Schlexer, K.L. Pilgrim, J.P. Copeland and M.K. Schwartz. 2009. Wolverine confirmation in California after Nearly a Century: Native or Long-Distance Immigrant? Northwest Science 83: 154-162.

Gaudinski, J.B., M.S. Torn, W.J. Riley, C. Swanston, S.E. Trumbore, J.D. Joslin, H. Majdi, T.E. Dawson, and P.J. Hanson. 2009.  Use of stored carbon reserves in growth of temperate tree roots and leaf buds: analyses using radiocarbon measurements and modeling. Global Change Biology 15:  992-1014.

Lilleskov, E.A., T.D. Bruns, T.E. Dawson and F.J Camacho. 2009. Water sources and controls on water-loss rates of epigeous ecotomycorrhizal fungal sporocarps during summer drought. New Phytologist 182: 483-494. 


Ewing, H.A., K.C. Weathers, P.H. Templer, T.E. Dawson, M.K. Firestone, A.M. Elliott and V.K.S Boukili. 2009. Fog water and ecosystem function: heterogeneity in a California Redwood forest.  Ecosystems 12: 417-433.


Cernusak, L.A., G. Tcherkez, C. Keitel, W.K. Cornwell, L.S. Santiago, A. Knohl, M.M. Barbour, D.G. Williams, P.B. Reich, D.S. Ellsworth, T.E. Dawson, H.G. Griffiths, G.D. Farquhar and I.J. Wright.  2009.  Why are non-photosynthetic tissues generally 13C enriched compared to leaves in C3 plants?  Review and synthesis of current hypotheses. Functional Plant Biology 36: 199-213.


Roden, J.S., J.A. Johnstone and T.E. Dawson. 2009.  Intra-annual variation in the stable oxygen and carbon isotope ratios of cellulose in tree rings of coast redwood (Sequoia sempervirens). The Holocene 19: 189-197.


Plamboeck, A.H., M. North and T.E. Dawson. 2008. Conifer seedling survival under closed-canopy and manzanita patches in the Sierra Nevada. Madrono 55: 191-201.


Koenig, W.D., D.J. Schaefer, S. Mambelli, and T.E. Dawson. 2008. Acorns, insects, and the diet of adult versus nestling Acorn Woodpeckers. Journal of Field Ornithology 79: 280–285.


Kahmen, A., K. Simonin, K.P. Tu, A. Merchant, A. Callister, T.E. Dawson and S.K. Arndt. 2008. Physiological and morphological effects on leaf water delta18O enrichment in different Eucalyptus species. Plant, Cell and Environment 31: 738-751.


Chen, Q., D.B. Baldocchi, P. Gong and T.E. Dawson.  2008.  Modeling radiation and photosynthesis of a heterogeneous savanna woodland landscape with a hierarchy of model complexity. Agricultural and Forest Meteorology 148: 1005-1020.


Anderson, R.L., R. Byrne and T. Dawson.  2008.  Stable isotope evidence for a foggy climate on Santa Cruz Island, California at ~16,000 cal. Yr. B.P. Palaeogeography, Palaeoclimatology, Palaeoecology 262: 176-181.


Burgess, S.O.O. and T.E. Dawson.  2008. Using branch and basal sap flow measurements to estimate whole-plant capacitance: a caution. Plant and Soil 305: 5-13.


Dawson, T.E. and R. T.W. Siegwolf (editors). 2007.  Stable Isotopes as Indicators of Ecological Change. Academic Press-Elsevier, San Diego. 417 pp.


Dawson, T.E. and R. T.W. Siegwolf. 2007. Using stable isotopes as indicators, tracers and recorders of ecological change: some context and background. Pp. 1-18 In: T.E. Dawson and R.T.W. Siegwolf (eds.) Stable Isotopes as Indicators of Ecological Change. Academic Press-Elsevier, San Diego.


Ehleringer, J.R. and T.E. Dawson. 2007. Stable isotopes record ecological change, but a sampling network will be critical. Pp. 19-24 In: T.E. Dawson and R.T.W. Siegwolf (eds.) Stable Isotopes as Indicators of Ecological Change. Academic Press-Elsevier, San Diego.


Grams, T.E.E., A.R. Kozovits, K-H. Häberle, R. Matyssek and T.E. Dawson.  2007. Combining delta13C and delta18O analyses to unravel competition, CO2 and O3 effects on the physiological performance of different-aged trees. Plant, Cell & Environment 30: 1023-1034.


Plamboeck, A.H., T.E. Dawson, L.M. Egerton-Warburton, M. North, T. Bruns and J.I. Querejeta.  2007.  Water transfer via fungal hyphae to conifer seedlings. Mycorrhiza 17: 439.447.

Burgess, S.O.O. and T.E. Dawson.  2007.  Predicting the limits to tree height using statistical regressions of leaf traits. New Phytologist 174: 626-636.


Lambrecht, S.C. and T.E. Dawson. 2007.  Correlated variation of floral and leaf traits along a moisture availability gradient. Oecologia  151: 574-583.


Wenk, E.H. and T.E. Dawson.  2007.  Interspecific differences in seed germination, establishment, and early growth in relation to preferred soil type in an alpine community. Arctic, Antarctic and Alpine Research 39: 165-176.


Fisher, J.B., D.D. Baldocchi, L. Mission, T.E. Dawson and A.H. Goldstein. 2007.  What the towers don’t see at night: Nocturnal sapflow in trees and shrubs at two AmeriFlux sites in California. Tree Physiology 27: 597-610.


Dawson, T.E., S.O.O. Burgess, K.P. Tu, R.S. Oliveira, J.B. Fisher, L.S. Santiago, K.S. Simonin and A.R. Ambrose.  2007. Nighttime transpiration in woody plants from contrasting ecosystems. Tree Physiology 27: 561-575.


Gregg, J.W., C.G. Jones and T.E. Dawson.  2006.  Physiological and developmental effects of ozone on cottonwood growth in urban and rural sites in the vicinity of New York City. Ecological Applications 16: 2368-2381.


Darrouzet-Nardi, A. C.M. D'Antonio and T.E. Dawson.  2006.  Depth of water acquisition by invading shrubs and resident herbs in a Sierra Nevada montane meadow. Plant and Soil 285: 31-43.


Burgess, S.O.O., J.A. Pitterman and T.E. Dawson.  2006.  Hydraulic efficiency and safety of branch xylem increases with height in Sequoia sempervirens (D. Don) crowns.  Plant, Cell & Environment 29: 229-239.


Gaudinski, J., T.E. Dawson, S. Quideau, T. Schuur, J. Roden, S. Trumbore, D.R. Sandquist, S.-W. Oh and R.E. Wasylishen.  2005.  A comparative analysis of cellulose extraction techniques for use with 13C, 14C and 18O isotopic measurements. Analytical Chemistry 77:  7212-7224.


Lee, J-E, R.S. Oliveiria, T.E. Dawson, and I. Fung.  2005.  Root functioning modifies seasonal climate. Proceedings of the National Academy of Sciences 102: 17576-17581.


Tolle, G., D. Culler, T. Dawson, K. Tu, W. Hong, R. Szewczyk, J. Polastre, S. Burgess, N. Turner, D. Gay and P. Buonadonna.  2005.  A Macroscope in the Redwoods. SenSys 218. Publication of the 3rd ACM Conference on Embedded Networked Sensor Systems; SenSys 2005.


 Corbin, J.D., M.A. Thomsen, T.E. Dawson and C.M. D'Antonio. 2005.  Summer water use by California coastal prairie grasses: fog, drought, and community composition. Oecologia 145: 511-521.


Oliveira, R.S., T.E. Dawson, S.O.O. Burgess and D.C. Nepstad.  2005. Hydraulic redistribution in three Amazonian tree species. Oecologia 145: 354-363.


Santiago, L.S., K. Silvera, J.L. Andrade and T.E. Dawson.  2005.  El uso de Isótopos Estables en Biología Tropical [English title: The use of stable isotope techniques in tropical biology]. Interciencia 30: 536-542.


Oliveira, R.S., T.E. Dawson, S.O.O. Burgess. 2005.  Evidence for direct water absorption by pseudostems of the desiccation-tolerant plant Vellozia  flavicans in the savannas of central Brazil. Journal of Tropical Ecology  21: 585-588.


 Dawson, T.E. and J.K. Ward.  2005.  Gender-specific ecophysiology, growth and habitat distribution in the riparian tree (Acer negundo), Boxelder. Pp. 129-131 In: R.J. Naiman, H. Décamps and M.E. McClain (eds.) RIPARIA – ecology, conservation and management of streamside communities. Elsevier Academic Press, San Diego, CA.


Juenger, T.J., J.K. McKay, N.J. Hausmann, J. Keurentjes, S. Sen, K.A. Stowe, T.E. Dawson, E.L. Simms and J.R. Richards.  2005.  Identification and characterization of QTL underlying whole-plant physiology in Arabidopsis thaliana: delta13C and stomatal conductance. Plant, Cell & Environment 28: 697-708.


Templer, P.H., G.M. Lovett, K. Weathers, S. Findlay, and T.E. Dawson.  2005.  Influences of tree species on 15N sinks and forest N retention in the Catskill Mountains, New York, USA.  Ecosystems 8: 1-16.


Tu, K.P. and T.E. Dawson.  2005.  Partitioning ecosystem respiration using stable carbon isotope analyses of CO2.  Pp. 125-153,  In: L.B. Flanagan, J.R, Ehleringer & D.E. Pataki (eds) Stable Isotopes and Biosphere-Atmosphere Interactions: Processes and Biological Controls. Elsevier Academic Press, San Diego, CA.


Hausmann, N.J., T.E. Juenger, S. Sen, K.A. Stowe, T.E. Dawson and E.L. Simms.  2005. Quantitative trait loci (QTL) affecting delta13C and response to soil water availability in Arabidopsis thaliana.  Evolution 59: 81-96. 

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