Research Interests:
My research
focuses primarily on the ecology of tropical savannas and
forests, with special emphasis on the Cerrado region of
central Brazil. I am primarily interested in
understanding the causes of variations in tree density in
tropical savannas and the consequences of land-use change on
regional climate. Current projects involve comparative
ecology of savanna and forest trees, fire ecology, and
land-atmosphere interactions. These projects involve a
range of approaches, including ecophysiology, population
dynamics, remote sensing and GCM climate modelling.
Selected Publications:
Jackson, R.B., Farley, K.A., Hoffmann, W.A.,
Jobbagy, E.G., McCulley, R.L. Vegetation change and
carbon and water dynamics. In J. Canadell, D. Pataki,
L. Pitelka (eds.) Terrestrial Ecosystems in a Changing World,
in press.
Lahoreau,
G., S. Barot, J. Gignoux, W.A. Hoffmann, S.A. Setterfield, and
P. R. Williams. 2006. Positive effect of seed size on
seedling survival in fire-prone savannas of Australia, Brazil
and West Africa. Journal of Tropical Ecology, in
press.
Hoffmann, W.A., Silva, E.R., Machado, G.C.,
Bucci, S.J., Scholz, F.G., Goldstein, G., Meinzer, F.C. 2005.
Seasonal leaf dynamics across a tree density gradient
in a Brazilian savanna. Oecologia, 145:
307-316.
Hoffmann,
W.A., Franco, A.C., Moreira, M.Z., Haridasan, M. 2005.
Specific leaf area explains differences in leaf traits
between congeneric savanna and forest trees.
Functional Ecology 19: 932-940.
Sternberg,
L.S.L., Bucci, S., Franco, A.C., Goldstein, G., Hoffmann,
W.A., Moreira, M.Z., Scholz, F. 2005. Long range
lateral root activity by Neo-tropical savanna trees.
Plant and Soil, 270:169-178.
Hoffmann,
W.A., Orthen, B. and Franco, A.C. 2004. Constraints to
seedling success of savanna and forest trees across the
savanna-forest boundary. Oecologia
140:252-260.
Hoffmann,
W.A., Lucatelli, V. M. P. C., Silva, F. J., Azeuedo, I. N. C.,
Marinho, M. da S., Albuquerque, A. M. S., Lopes, A. de O.,
Moreira, S. P. 2004. Impact of the invasive grass
Melinis minutiflora at the savanna-forest ecotone in the
Brazilian Cerrado. Diversity and Distributions, 10:
99-103.
Bucci
S.J., Scholz F.G., Goldstein G., Meinzer F.C , Hinojosa J.A.,
Hoffmann W.A., and Franco, A.C. 2004. Processes
preventing nocturnal equilibrium between leaf and soil water
potential in tropical savanna woody species, Tree
Physiology, 24: 1119-1127.
Hoffmann, W.A., B. Orthen,
and P.K.V. Nascimento. Comparative fire ecology of
tropical savanna and forest trees. Functional
Ecology, 17: 720-726
Hoffmann, W.A., W. Schroeder and
R.B. Jackson. Regional feedbacks among climate, fire,
and tropical deforestation. Journal of Geophysical
Research – Atmospheres, 108, DOI:2003JD003494
Hoffmann,
W.A. and O.T. Solbrig. 2003. The role of topkill
in the differential response of savanna woody species to
fire. Forest Ecology and Management,
180:273-286.
Hoffmann, W.A. and A.C. Franco.
Comparative growth analysis of tropical savanna and
forest trees using phylogenetically-independent contrasts.
Journal of Ecology, 91: 475-484.
Hoffmann, W.
A., W. Schroeder, and R. B. Jackson. 2002. Positive
feedbacks of fire, climate, and vegetation change and the
conversion of tropical savannas. Geophysical Research
Letters, 15: doi: 10.1029/2002GL01542
Hoffmann,
W.A. and Moreira, A.G. 2002 The Role of Fire in
Population Dynamics of Woody Plants, Pp. 159-177 in P.S.
Oliveira and R.J. Marquis (eds.) The Cerrados of Brazil:
Ecology and Natural History of a Neotropical Savanna,
Columbia University Press, New York.
Dickinson, R.E., J.A.
Berry, G.B. Bonan, G.J. Collatz, C.B. Field, I.Y. Fung, M.
Goulden, W.A. Hoffmann, R. Jackson, R. Myneni, P. Sellers, M.
Shaikh. 2002. Nitrogen controls on climate model
evapotranspiration. Journal of Climate,
15:278-295.
Hoffmann, W.A. and H. Poorter. 2002.
Avoiding bias in calculations of relative growth rate.
Annals of Plant Biology80:37-42 .
Hoffmann,
W.A. 2002. Direct and indirect effects of fire on
radial growth of cerrado savanna trees. Journal
of Tropical Ecology 18:137-142.
Silva, G.F., R.L.C.
Ferreira, W.A. Hoffmann, N.C. Fiedler, G. Janin. 2002.
Optimization applied to management of natural
forests. ETFRN News 36: 26-27.
Hoffmann,
W.A., F.A. Bazzaz, N.J. Chatterton, P. Harrison, and R.B.
Jackson. 2000. Elevated CO2 enhances resprouting of a
tropical savanna tree. Oecologia, 123(3)
312-317.
Hoffmann, W. A. and R.B. Jackson. 2000.
Vegetation-climate feedbacks in the conversion of
tropical savanna to grassland. Journal of
Climate 13:1593-1602.
Hoffmann, W. A. 2000.
Post-establishment seedling success of savanna and
forest species in the Brazilian Cerrado. Biotropica,
32(1):62-69
Hoffmann, W.A. 2000. The relative
importance of sexual and vegetative reproduction in cerrado
woody plants. Pp. 231-234 in T.B. Cavalcanti and
B.M.T. Walter (eds.) Tópicos Atuais em Botânica.
EMBRAPA, Brasília.
Jackson R.B., L. A Moore, W. A.
Hoffmann, W. T. Pockman, and C. R. Linder. 1999.
Ecosystem rooting depth determined with caves and
DNA. Proceedings of the National Academy of Science
96:11387-11392.
Hoffmann, W. A. 1999. Fire and
population dynamics of woody plants in a Neotropical savanna:
matrix model predictions. Ecology
80:1354-1369.
Jackson, R. B., W. T. Pockman, and W. A.
Hoffmann. 1999. Structure and function of root
systems. Pp 195-220 in: F. I. Pugnaire and F.
Valladeres (eds). Handbook of Plant Functional Ecology, Marcel
Dekker, Inc.
Hoffmann, W. A. 1998. Post-burn
reproduction of woody plants in a Neotropical savanna: the
relative importance of sexual and vegetative reproduction.
Journal of Applied Ecology 35:422-433.
Archer,
S., M. Coughenour, C. Dall'Aglio, C. W. Fernandez, J. Hay, W.
Hoffmann, C. Klink, J. F. Silva, and O. T. Solbrig. 1996.
Savanna biodiversity and ecosystem
properties. Pp 207-215 in O. T. Solbrig, E. Medina,
J. F. Silva (eds), Biodiversity and Savanna Ecosystem
Properties. Springer-Verlag, Berlin.
Hoffmann, W. A.
1996. The effects of cover and fire on seedling
establishment in a neotropical savanna. Journal of
Ecology. 84:383-393
