Representative
Research Interests |
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Groundcover
Diversity & Dynamics in Longleaf Pine Ecosystems |
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 Balduina uniflora |
 Prescribed burn |
 Plot with Sarracenia |
Remnant and restored Longleaf Pine Ecosystems of the southeastern United States often support extreme levels of groundcover biodiversity. Our team from Louisiana State University (including Bill Platt, Jonathan Myers, Natalia Aristizabal, and former post-docs Heather Passmore & Paul Gagnon) strives to contribute towards our mechanistic understanding of these extraordinary communities through long-term observations and experiments on properties owned and managed by the Girl Scouts of America (Camp Whispering Pines) and The Nature Conservancy (preserves near Abita Springs and Lake Ramsey) in southeastern Louisiana. The project also provides abundant opportunities to contribute towards conservation in Longleaf Ecosystems, through educational and management-based outreach activities. We thank the Girl Scouts of America, the National Science Foundation, and The Nature Conservancy for supporting our project.
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Forest
Diversity & Dynamics in Intact & Fragmented Forests of the Central Amazon |
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 Alexandre Oliveira |
 First census of Brazilian FDP |
 A new species of shrub from our FDP |
Alexandre Adalardo de Oliveira (Universidade de São Paulo), Alberto Vicentini (Instituto Nacional de Pesquisas da Amazônia) and I are spear-heading the effort to add a new node (near Manaus, Brazil) to the network of Forest Dynamics Plots (FDPs) coordinated by the Center for Tropical Forest Science (CTFS), a research branch of the Smithsonian Tropical Research Institute (STRI). We thank CTFS, the Louisiana Board of Regents, and the Richard & Rhoda Goldman Fund for supporting our project. Visit the Smithsonian
Institution Global Earth Observatories Web page In a separate, but coordinated endeavor funded by the National Science Foundation, Bill Laurance (James Cook University) and I supervised the most recent census of medium-sized to large trees (>10-cm dbh) within the 1-ha phytodemographics plots of the Biological Dynamics of Forest Fragments Project (BDFFP), along with the first comprehensive census of smaller sapling recruits in subplots within the BDFFP fragments and associated continuous forest.
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Effects
of Soil-Borne Resources on the Diversity, Dynamics & Structure of Tropical Forests |
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 Soil extractions, Manaus, Brazil |
 Two species on Panama FDP |
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To better understand patterns of tropical tree distribution, diversity, and dynamics, we are systematically characterizing soil properties and hydrology of selected Center for Tropical Forest Science (CTFS) Forest Dynamics Plots (FDPs). Principal collaborators: Jim Dalling - U. Illinois; Robert John-Chandran - ATREE (India); Joe Yavitt - Cornell U.; Bob Stallard - U. S. Geological Survey. We thank the National Science Foundation and the Smithsonian Tropical Research Institute (STRI) for supporting this collaborative effort.
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Nutrient
Limitation in a Lowland Tropical Forest
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 Gigante Peninsula field site |
 Rain-shelter denizen |
 "Green" and "brown" food webs |
We have been fertilizing 40 x 40-m plots of old-growth forest in the Republic of Panama since 1998 to test a variety of predictions concerning nutrient limitation within both the "green" and "brown" food webs of lowland tropical forests. Principal collaborators: Joe Wright & Milton García - Smithsonian Tropical Research Institute; Joe Yavitt - Cornell U.; Mike Kaspari - U. Oklahoma; Jennifer Powers - U. Minnesota. We thank the Smithsonian Institution and the Smithsonian Tropical Research Institute for supporting this project. |
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The
Light- vs. Nutrient-Capture Trade-off of Quadrella antonensis [Capparaceae] |
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 Q. antonensis |
 Cerro Campana field site |
 Q. antonensis |
Quadrella
antonensis (formerly Capparis antonensis) is an unusual
montane shrub, endemic to Panama. Individuals apparently sacrifice light-capture
efficiency to obtain nutrients from decomposing litter held in their
leafy "trash baskets." Principal collaborators: Jim Dalling
- U. Illinois; Bob Pearcy - U. California at Davis; María Sánchez
de Stapf - Smithsonian Tropical Research Institute. We thank the Smithsonian
Tropical Research Institute for supporting this project. |
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The
Influence of Specialist
Homopteran Enemies on Recruitment |
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 Unattacked Tetragastris seedling |
 Attacked Tetragastris seedling |
 Pit-galling homopterans |
This
endeavor builds upon previous, phenomenological work that demonstrated
pervasive density-dependent recruitment among relatively common species
of trees and lianas in the forest on Barro Colorado Island, Republic
of Panama (Harms et al. 2000). Through this project we hope
to provide insights into the mechanisms underlying density-dependence
for this common species. |
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Water
Calyces Dissuade Specialist Floral Enemies |
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 Photo © Greg Dimijian |
 Photo © Jane Carlson |
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Chrysothemis
friedrichsthaliana [Gesneriaceae] is one of a unique set of plants
that produce "water calyces," i.e., upright calyces
that fill with water that covers the additional floral structures during
their early development. Jane Carlson's experiments on the Osa Peninsula
in Costa Rica demonstrated that flowers with artificially drained calyces
suffered higher rates of attack by a specialist microlepidopteran. |
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