OOS 36 - Large-Scale Manipulative Experiments in the Tropics: Population, Community, and Ecosystem Level Responses

Thursday, August 11, 2011: 8:00 AM-11:30 AM
12A, Austin Convention Center
Organizer: Diana C. Garcia-Montiel
Moderator: Diana C. Garcia-Montiel
Among the multiple research approaches used to study ecosystem dynamics, large-scale experimental manipulations are the hallmark for establishing process-level understanding. Although long-term monitoring research is tremendously important for uncovering key ecological components of complex ecosystem dynamics, establishing the temporal context of processes and detecting the effects of infrequent disturbance events, determining causality for many patterns is impossible because of lacking controlled conditions. Comparative studies are important for unraveling broad spatial patterns, but they are unable to predict how a given ecosystem will respond to fluctuations. Manipulative experiments are designed to measure the effect of altering key variables in the context of other factors controlling ecosystem processes. However, because processes, patterns, and biotic responses are scale dependent, the mechanistic interpretation derived from the experimental manipulation is also constrained by scale dependency. Often, experiments are designed at a temporal and spatial scale with other experiments nested at lower scales, but still accounting for landscape heterogeneity is difficult due to logistical difficulties. Additionally, the manipulations usually apply perturbations at a level of intensity different from the one produced by the real event under investigation. Because of all these factors, ecologists need to asses how effective are large-scale manipulations disentangling the mechanisms behind observed trends which are then going to be used for prediction. This assessment is particularly important in the context of tropical regions where the implementation and maintenance of continuous monitoring activities are constrained by limited financial support in remote areas with difficult access. We anticipate that this symposium will serve as a focal point for ecologists to discuss and evaluate the contributions and limitations of experiments involving large-scale manipulations and their role producing process-level understanding of ecosystem trends. We will cover a range of perspectives from population, community and ecosystem processes, to assess what we learn from this kind of experimentation. The first four talks will present detailed description of large-scale manipulative experiments in terrestrial ecosystems conducted along Panama and Brazil. The next three talks will offer specific examples of uncovered processes from a large-scale experiment in Puerto Rico. The eighth talk will present an example from the perspective of ecologists trying to manipulate mobile organisms. The final talk will focus on aquatic ecosystems to describe how the large-scale, inter-site LINX experiment, contributed to study N saturation in a tropical forest in Puerto Rico. The last 30min will be reserved for a panel discussion and to provide opportunity for audience feedback.
8:00 AM
Limitation by multiple nutrients revealed by a long-term, large-scale nutrient augmentation experiment in lowland Panama
Kyle E. Harms, Louisiana State University; Joseph B. Yavitt, Cornell University; Milton N. Garcia, Smithsonian Tropical Research Institute; Michael Kaspari, University of Oklahoma; S. Joseph Wright, Smithsonian Tropical Research Institute
8:20 AM
Drought impacts on physiology and mortality in rain forest: Results from a large scale rainfall exclusion experiment in Amazonia and their wider applicability
Patrick Meir, University of Edinburgh; Rosie A. Fisher, National Center for Atmospheric Research; ACL da Costa, Federal University of Para; D. Galbraith, University of Edinburgh; S. Almeida, Museu Paraense Emilio Goeldi; Cláudio J. R. de Carvalho, Embrapa Amazônia Oriental, Brazil; DB Metcalfe, Swedish University of Agricultural Sciences; E. Sotta, Silvicultura e Ecologia Florestal, Embrapa
8:40 AM
Local and regional carbon consequences of severe droughts in Amazonia: Results from a large-scale partial throughfall experiment and field-plots experiencing droughts
Paulo M. Brando, Instituto de Pesquisa Ambiental da Amazônia (IPAM); Daniel C. Nepstad, Instituto de Pesquisa Ambiental da Amazônia (Amazon Institute of Environmental Research); S.L. Lewis, University of Leeds; Oliver Phillips, University of Leeds; Eric A. Davidson, The Woods Hole Research Center, Massachusetts; Geertje M. F. van der Heijden, University of Sheffield
9:00 AM
Size, species, and fire behaviour predict tree and liana mortality from experimental burns in the Brazilian Amazon
Jennifer K. Balch, University of Colorado-Boulder; Daniel C. Nepstad, Instituto de Pesquisa Ambiental da Amazônia (Amazon Institute of Environmental Research); Lisa M. Curran, Stanford University; Paulo M. Brando, Instituto de Pesquisa Ambiental da Amazônia (IPAM); Osvaldo Portela, Instituto de Pesquisa Ambiental da Amazônia (Amazon Institute of Environmental Research); Paulo G.P. dos Santos, Universidade Federal do Pará; Jonathan D. Reuning-Scherer, Yale University; Oswaldo Carvalho, Instituto de Pesquisa Ambiental da Amazônia (Amazon Institute of Environmental Research)
9:20 AM
Vegetation dynamics after large-scale artificial canopy opening and detritus deposition in a tropical forest in Puerto Rico
Aaron Shiels, USDA, APHIS, National Wildlife Research Center; Jess K. Zimmerman, University of Puerto Rico - Rio Piedras; Diana C. Garcia-Montiel, University of Puerto Rico; Inge Jonckheere, Katholieke Universiteit Leuven; Jennifer A. Holm, Lawrence Berkeley National Laboratory; David Horton, Washington University in St. Louis; Nicholas Brokaw, Institute for Tropical Ecosystem Studies University of Puerto Rico-Río Piedras
9:40 AM
10:10 AM
A canopy trimming experiment in Puerto Rico: Effects on invertebrates, microbes and decay
Grizelle González, International Institute for Tropical Forestry; D. Jean Lodge, USDA-Forest Service; Sharon A. Cantrell, Universidad del Turabo; Barbara Richardson, Luquillo Experimental Forest LTER, Puerto Rico
10:30 AM
Experimental decoupling of the effects of hurricane disturbance on tropical gastropod populations and communities
Michael R. Willig, University of Connecticut; Christopher P. Bloch, Bridgewater State College; Steven J. Presley, University of Connecticut
10:50 AM
Forest nitrogen saturation and stream nitrogen enrichment: Are there landscape-scale responses to increased N levels in the tropics?
William H. McDowell, University of New Hampshire; Daniela F. Cusack, UC - Los Angeles; Debora Figueroa-Nieves, University of New Hampshire; Jody D. Potter, University of New Hampshire
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