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RESEARCH INTERESTS
Physiological ecology of tropical rainforest plants
Applications of basic research to the conservation of tropical rainforests
Defenses of tropical rainforest plants against herbivores, including chemical defenses
Ecophysiology of rainforest trees, including drought tolerance
PUBLICATIONS
Posters
Delayed greening in young tropical leaves
It's a jungle out there
Plants, especially in tropical rainforests, experience
intense attack by herbivores and pathogens on the young,
expanding leaves, and have a remarkable array of
defenses against these enemies. Herbivores and
pathogens evidently have selected for changes in the way
in which leaves develop. Tropical rainforest plants often
have leaves that appear white while expanding. I have
shown that delayed chloroplast development results in
less investment per dry weight of leaf and hence a
decrease in the loss to herbivores and pathogens. Further
work carried out in Neotropical, Southeast Asian and
African rainforests has identified at least three other
developmental adaptations of rainforest plants, rapid
leaf expansion, the toxicity of the compounds in the
young leaves and highly synchronous leaf flushes. How
did all of this evolve? A simple evolutionary scenario
suggests that the evolution of toxic secondary
metabolites, or the failure to do so, has been key to the
evolution of other developmental adaptations. Current
work focuses on an analysis of the evolution of
secondary metabolites by comparing species with the
most and the least effective chemical defenses.
I also am interested in the ecophysiology of rainforest
plants. I have focused on shade-tolerant species since
they constitute more than 80% of the stems and
species and, surprisingly, are the most important
component of treefall light gaps. While differences
between shade-tolerant and gap-requiring species are
well established, the extent of physiological
differentiation among the shade-tolerant species is
poorly understood. The compelling conclusion from this
work is that the shade-tolerant species are much more
physiologically differentiated than might have been
expected. Because rainforests are highly dynamic
communities, a much better understanding of the
physiology of the shade-tolerant species will be
essential for explaining how climate change may be
affecting the rainforest plant community. Current work
focuses on the importance water stress in rainforest
habitats.
I am committed to using my skills to promote
conservation. Since 1993, I have been developing a
program for drug discovery from rainforest plants. The
issue that we address is critical. Unless more
successful models for bioprospecting are developed, we
will lose one of the major arguments for the
conservation of tropical rainforests that they are a
storehouse of potential medicines. Our results to date
indicate that bioprospecting using insights derived from
our ecological work on leaf development is likely to be
substantially more productive than conventional
approaches. Another goal of our project is to carry out
the research within the source county, Panama, in order
to promote the development of the scientific
infrastructure as well as conservation in Panama.
A second conservation-oriented project is a study of the
regeneration, growth, physiology, distribution and
management of Prioria copafera, an important
lumber tree in Panama. The project has considerable
conservation implications because most of the
Prioria copaifera stands lie in the buffer zone of a
spectacular natural area, Darien National Park, a World
Heritage Site and a World Biosphere Reserve. Proper
management of the buffer zone during the current period
of population growth and influx of colonists will be
required in order to ensure the long-term protection of
the Darien park itself.
Selected Publications
Coley, P. D. and T. A. Kursar. (1996) Anti-herbivore
defenses of young tropical leaves: physiological
constraints and ecological trade-offs. In: S. S.
Mulkey, R. L. Chazdon, and A. P. Smith (eds)
Tropical Forest Plant Ecophysiology, Chapman and
Hall, N. Y., pp 305-336.
Kursar, T. A. (1998) Relating tree physiology to
past and future changes in tropical rainforest tree
communities. Climatic Change 39:363-379.
Lovelock, C. E., T. A. Kursar, J. B. Skillman and K.
Winter. (1998) Photoinhibition in tropical forest
understory species with short- and long-lived
leaves. Functional Ecology 12: 553-560.
Nelson, A. C. and T. A. Kursar. (1999) Interactions
among plant defense compounds: a method for
analysis. Chemoecology 2:81-92.
Tobin, M. F., O. R. Lopez, and T. A. Kursar. (1999)
Responses of tropical understory plants to a severe
drought: tolerance and avoidance of water stress.
Biotropica 31:570-578.
Kursar, T. A. and P. D. Coley. (1999) Contrasting
modes of light acclimation in two species of the
rainforest understory. Oecologia 121:489-498.
Lopez, O. R. and T. A. Kursar. (1999) Flooding
tolerance of four tropical tree species. Tree
Physiology 19:925-932.
Kursar, T. A., T. L. Capson, P. D. Coley, D. G. Corley,
M. B. Gupta, L. A. Harrison, E. Ortega-Barrķa and D. M.
Windsor. (1999) Ecologically guided
bioprospecting in Panama. Pharmaceutical Biology
37, Supplement: 114-126.
Arnold, A. E., Z. Maynard, G. S. Gilbert, P. D. Coley
and T. A. Kursar. (2000) Are tropical fungal
endophytes hyperdiverse? Ecology Letters 3:267-
274.
Torti, S. D., P. D. Coley and T. A. Kursar. (2001)
Causes and consequences of monodominance in
tropical lowland rainforests. American Naturalist
157:141-153.
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