176 Kaoru Kitajima and Lourens Poorter
allocation patterns place a high priority on fast
growth thrive in gaps, but such allocation patterns
are accompanied by high susceptibility to disease,
herbivores, and physical damage that makes it
impossible to survive in shaded understory. A
contrastin gallocation pattern is to place priority
in persistence through allocation to defense and
storage, which results in inherently slow growth.
Thus, we propose that a key to resolve this appar-
ent paradox lies in the role of natural enemies in
modulatin gthe relative importance of growth and
survival alon gthe resource availability gradient.
For proper evaluation of niches as a mechanism
to promote species coexistence, future studies need
to address how adult trees exert asymmetric com-
petition for light and other resources, as well
as demographic integration of growth–survival
trade-offs through multiple ontogenetic stages.
ACKNOWLEDGMENTS
We gratefully acknowledge constructive com-
ments at various stages of preparation of this
chapter from D. Tilman, S. Pacala, M. Walters,
S. Mulkey, C. Augspurger, E. Herre, F. Valladares,
B. Bolker, E. Leigh, L. Sack, F. Putz, S.J. Wright,
H. Muller-Landau, F. Bongers, R. Kobe, and an
anonymous reviewer. K.K. was supported by NSF-
EEP0093303. L.P. was supported by Veni grant
863.02.007 from the Netherlands Organization
of Scientific Research (NWO).
REFERENCES
Agyeman, V.K., Swaine, M.D., and Thompson, J. (1999)
Responsesof tropicalforesttreeseedlingstoirradiance
and the derivation of a light response index.Journal of
Ecology87, 815–827.
Ahumada, J.A., Hubbell, S.P., Condit, R., and Foster, R.B.
(2004)Long-termtreesurvivalinaNeotropicalforest:
the influence of local biotic neighborhood. In E. Losos
and E.G. Leigh, Jr. (eds),Tropical Forest Diversity and
Dynamism. University of Chicago Press, Chicago, IL,
pp. 408–432.
Alvarez-Clare, S. and Kitajima, K. (2007) Physical
defense traits enhance seedlin gsurvival of neotropical
tree species.Functional Ecology21, 1044–1054.
Augspurger, C.K. (1984a) Seedling survival of tropical
tree species; interactions of dispersal distance, light
gaps, and pathogens.Ecology65, 1705–1712.
Augspurger, C.K. (1984b) Light requirements of
neotropical tree seedlings: a comparative study
of growth and survival. Journal of Ecology72,
777–795.
Avalos, G., Mulkey, S.S., Kitajima, K., and Wright,
S.J. (2007) Canopy colonization strategies of two
liana species in a tropical dry forest.Biotropica39,
393–399.
Baraloto, C., Goldberg, D.E., and Bonal, D. (2005) Per-
formance trade-offs amon gtropical tree seedlin gs in
contrastin gmicrohabitats.Ecology86, 2461–2472.
Bloor, J.M.G. and Grubb, P.J. (2003) Growth and mortal-
ity in high and low light: trends among 15 shade-
tolerant tropical rain forest tree species.Journal of
Ecology91, 77–85.
Boot, R.G.A. (1996) The significance of seedling size
and growth rate of tropical rain forest tree seedlings
for regeneration in canopy openings. In M.D. Swaine
(ed.),The Ecology of Tropical Forest Tree Seedlings,
UNESCO, Paris, pp. 267–284.
Brokaw, N. and Busing, R.T. (2000) Niche versus chance
and tree diversity in forest gaps.Trends in Ecology and
Evolution15, 184–188.
Brokaw, N.V.L. (1987) Gap-phase regeneration of three
pioneer tree species in a tropical forest.Journal of
Ecology75, 9–19.
Brown, N. (1993) The implications of climate and gap
microclimate for seedlin g growth conditions in a
Borneanlowlandrainforest.Journal of Tropical Ecology
9, 153–168.
Brown, N.D. and Jennings, S. (1998) Gap-size
niche differentiation by tropical rainforest trees: a
testable hypothesis or a broken-down bandwagon. In
D.M. Newbery, H.H.T. Prins, and N.D. Brown (eds),
Dynamics of Tropical Communities.Blackwell Science,
Oxford, pp. 79–94.
Burslem, D.F.R.P., Grubb, P.J., and Turner, I.M. (1996)
Responses to simulated drought and elevated nutri-
ent supply amon gshade-tolerant tree seedlin gs of
lowland tropical forest in Singapore.Biotropica 28 ,
636–648.
Canham, C.D., Finzi, A.D., Pacala, S.W., and
Burbank, D.H. (1994) Causes and consequences of
resource heterogeneity in forests: interspecific varia-
tion in light transmission by canopy trees.Canadian
Journal of Forest Research24, 337–340.
Cavender-Bares, J., Ackerly, D.D., Baum, D.A., and
Bazzaz, F.A. (2004a) Phylogenetic overdispersion in
Floridian oak communities.American Naturalist163,
823–843.
Cavender-Bares, J., Kitajima, K., and Bazzaz, F.A.
(2004b) Multiple trait associations in relation to
habitat differentiation amon g17 Floridian oak
species.Ecological Monographs74, 635–662.