SIGEO/CTFS Staff Scientist: Ecologist and Temperate Program Coordinator
Address: Smithsonian Environmental Research Center
647 Contees Wharf Road
Edgewater, MD 21037-0028
Telephone: (443) 482.2262
FAX: (443) 482.2380
Climate change and terrestrial systems.
Carbon movement through forests.
Quantitative methods in ecology and evolution.
My primary research focuses on the ecological mechanisms that structure forest communities and determine their fine- and large-scale spatial and temporal dynamics. This program spans topics as diverse as forest demography, functional traits, canopy structure and change over succession, spatial patterns and shifts of temperate and tropical forest tree species, and how climate change influences biomass shifts over stand development. This work combines field research, advanced statistical analyses, computer simulations, and enjoys the collaboration of a global network of scientists in forest ecology, statistics, computer science, and climate science.
The SIGEO network of forest plots has long offered forest scientists an important way to test whether local observed patterns reflect global processes. The new, temperate forest plots extend this program to critical biomes that show high-biomass and high growth, and many of the spatial and temporal patterns observed in tropical forests, all with many fewer species. Further, most temperate forests have a long history of human influence, both directly and indirectly, and their study offers critical information about how natural systems can be affected by and respond to human influence. The most exciting component of the temperate program in SIGEO is the extended network of scientists who bring expertise in numerous fields to bear on the important challenges facing Earth’s forest systems.
Education and Degrees
University of Tennessee, Knoxville. Ph.D. Ecology and Evolutionary Biology. 2007.
University of Tennessee, Knoxville. M.S. Statistics 2006
University College Dublin M.A. in English Literature. 1993
University of Texas, Austin. B.A. in Honors Liberal Arts. 1992
Jean-Remy Makana, Corneille N. Ewango, Richard Condit, Sean M. McMahon, Sean C. Thomas, , Terese B. Hart, Richard Condit. (in press). Trends of forest change in monodominant and mixed Central African old-growth. Journal of Tropical Ecology.
McMahon, S. M., Harrison, S. P., Armbruster, W. S., Bartlein, P.J., Beale, C, Edwards, M. E., Kattge, J, Midgley, G, Morin, X, and Prentice, I C. (2011). Improving assessments of climate-change impacts on global biodiversity. Trends in Ecology and Evolution. Vol. 26, No. 5
McMahon, S. M, C.J.E. Metcalf, and C. Woodall. (2011). High-dimensional coexistence of temperate tree species: functional traits, demographic rates, life-history stages, and their physical context. PLoS ONE. 6(1): e16253. DOI: 10.1371/journal.pone.0016253.t002.
Salk, C. F. and S. M. McMahon. (2010). Trait-environment interactions explain sprouting patterns in tropical tree species. OECOLOGIA. Volume 166, Number 2, 485-492, DOI: 10.1007/s00442-010-1850-7.
McMahon, S. M., Parker, G. G., Miller, D. R. 2010. Evidence for a recent increase in forest growth. Proceedings of the National Academy of Sciences. 107:3611–3615.
Clark, James S., D. Bell, C. Chu, B. Courbaud, M. Dietze, M. Hersh, J. HilleRisLambers, I. Ibáñez, S. LaDeau, S. M. McMahon, J. Metcalf, J. Mohan, E. Moran, L. Pangle, S. Pearson, C. Salk, Z. Shen, D. Valle, P. Wyckoff. 2010. High dimensional coexistence based on individual variation: a synthesis of evidence. Ecological Monographs.
McMahon, S. M., M. C. Dietze, M. H. Hersh, E. V. Moran, and J. S. Clark. 2009. A predictive framework to understand forest responses to global change. The Year in Ecology and Conservation Biology. Annals of the New York Academy of Sciences. 1162: 221–236.
McMahon, S. M. and C. J. E. Metcalf. 2008. Transient sensitivities of non-indigenous shrub species indicate complicated invasion dynamics. Biological invasions. 10(6): 833-846.