|
Ecology of Savanna-Forest Boundaries |
||||||||
|
Change
in the frequency of fire and other anthropogenic disturbances have shifted the
balance between savanna and forest vegetation over much of the seasonal tropics.
Understanding how disturbance and climate change determine the distribution
of savanna and forest has been the focus of various modeling studies, though
these have invariably ignored that there are fundamental differences between
savanna and forest trees. To understand how plant traits determine the
dynamics of the savanna-forest boundary, we have been comparing the ecology,
morphology, and ecophysiology of savanna and forest trees using
phylogenetically-independent contrasts. |
|
|||||||
|
|
|
|
|
|
||||
|
Phylogeny of 12 congeneric species pairs, each containing
one forest species and one savanna species. Savanna
species are marked with “*”. |
|
|
An example of a congeneric pair containing a
forest species, Hymenaea courbaril (left) and a savanna species Hymenaea
stigonocarpa (right) |
|||||
|
|
|
|||||||
|
Fertilizing
the savanna-forest boundary |
|
|
|
|
|
|
||
|
Publications Geiger, E.L., Gotsch, S.G., do Vale, G.D., Haridasan, M., Franco,
A.C., & Hoffmann, W.A. (2011) Distinct roles of savanna and forest tree
species in regeneration following fire suppression in a Brazilian savanna. Journal
of Vegetation Science, in press. Ratnam, J., Bond, W.J., Fensham, R.J., Hoffmann, W.A., Archibald, S., Lehmann,
C.E.R., Anderson, M.T., Higgins, S.I., & Sankaran, M. (2011) When is a
"forest" a savanna, and why does it matter? Global Ecology and
Biogeography, In press. Gotsch, S.G., Geiger, E.L., Franco, A.C., Goldstein, G., Meinzer,
F.C., & Hoffmann, W.A. (2010) Allocation to leaf area and sapwood area
affects water relations of co-occurring savanna and forest trees. Oecologia,
163, 291–301. Silva, L.C.R., Haridasan, M., Sternberg, L.S.L., Franco, A.C., &
Hoffmann, W.A. Not all forests are expanding over central Brazilian savannas.
Plant and Soil, 333, 431-442. Hoffmann, W.A., R.
Adasme, M. Haridasan, M. Carvalho, E. L. Geiger, M. A. B. Pereira, S.
G. Gotsch, and A. C. Franco (2009). Tree
topkill, not mortality, governs the dynamics of alternate stable states at
savanna-forest boundaries under frequent fire in central Brazil. Ecology, 90:1327-1337. Hoffmann, W.A. & Franco, A.C. (2008) The
importance of evolutionary history in studies of plant physiological ecology:
examples from cerrados and forests of central Brazil. Brazilian
Journal of Plant Physiology, 20, 247-256. Silva, L.C.R, L.
Sternberg, M. Haridasan, W. Hoffmann, F. Miralles-Wilhelm. A. C Franco
(2008) Expansion of gallery forests into
central Brazilian savannas. Global Change Biology, 14:
2108-2118. Hao, G.-Y. Hoffmann,
W.A. Scholz, F.G. Bucci, S.J. Meinzer, F.C. Franco, A.C. Cao, K.-F.
Goldstein, G. (2008) Stem and leaf hydraulics of
congeneric tree species from adjacent tropical savanna and forest ecosystems.
Oecologia 155:405-415. Hoffmann, W.A.,
Franco, A.C., Moreira, M.Z., 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., 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. Hoffmann, W.A., B. Orthen, and
P.K.V. Nascimento. 2003. Comparative
fire ecology of tropical savanna and forest trees. Functional Ecology,
17: 720-726 Hoffmann, W.A. and A.C. Franco.
2003. Comparative
growth analysis of tropical savanna and forest trees using
phylogenetically-independent contrasts. Journal of Ecology, 91:
475-484. Hoffmann,
W. A. 2000. Post-establishment seedling
success of savanna and forest species in the Brazilian Cerrado. Biotropica,
32(1):62-69 |
||||||||
