ALBERT

Description: Fully mapped tree census plots of large area, 25 to 52 hectares, have now been completed at six different sites in tropical forests, including dry deciduous to wet evergreen forest on two continents. One of the main goals of these plots has been to evaluate spatial patterns in tropical tree populations. Here the degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree. When all individuals larger than 1 centimeter in stem diameter were included, nearly every species was more aggregated than a random distribution. Considering only larger trees (〉/= 10 centimeters in diameter), the pattern persisted, with most species being more aggregated than random. Rare species were more aggregated than common species. All six forests were very similar in all the particulars of these results.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Condit, R -- Ashton, P S -- Baker, P -- Bunyavejchewin, S -- Gunatilleke, S -- Gunatilleke, N -- Hubbell, S P -- Foster, R B -- Itoh, A -- LaFrankie, J V -- Lee, H S -- Losos, E -- Manokaran, N -- Sukumar, R -- Yamakura, T -- New York, N.Y. -- Science. 2000 May 26;288(5470):1414-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Unit 0948, APO AA 34002-0948, USA. ctfs@tivoli.si.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10827950" target="_blank"〉PubMed〈/a〉

Description: Light gap disturbances have been postulated to play a major role in maintaining tree diversity in species-rich tropical forests. This hypothesis was tested in more than 1200 gaps in a tropical forest in Panama over a 13-year period. Gaps increased seedling establishment and sapling densities, but this effect was nonspecific and broad-spectrum, and species richness per stem was identical in gaps and in nongap control sites. Spatial and temporal variation in the gap disturbance regime did not explain variation in species richness. The species composition of gaps was unpredictable even for pioneer tree species. Strong recruitment limitation appears to decouple the gap disturbance regime from control of tree diversity in this tropical forest.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hubbell -- Foster -- O'Brien -- Harms -- Condit -- Wechsler -- Wright -- de Lao SL -- New York, N.Y. -- Science. 1999 Jan 22;283(5401):554-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉S. P. Hubbell, S. T. O'Brien, B. Wechsler, Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA. R. B. Foster, K. E. Harms, R. Condit, S. J. Wright, S. Loo de Lao, Smithsonian Tropical Research Institute, Post.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9915706" target="_blank"〉PubMed〈/a〉

Description: By integrating a wide range of experimental, comparative, and theoretical approaches, ecologists are starting to gain a detailed understanding of the long-term dynamics of vegetation. We explore how patterns of variation in demographic traits among species have provided insight into the processes that structure plant communities. We find a common set of mechanisms, derived from ecological and evolutionary principles, that underlie the main forces shaping systems as diverse as annual plant communities and tropical forests. Trait variation between species maintains diversity and has important implications for ecosystem processes. Hence, greater understanding of how Earth's vegetation functions will likely require integration of ecosystem science with ideas from plant evolutionary, population, and community ecology.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rees, M -- Condit, R -- Crawley, M -- Pacala, S -- Tilman, D -- New York, N.Y. -- Science. 2001 Jul 27;293(5530):650-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Imperial College and NERC Centre for Population Biology, Silwood Park, Ascot, Berks SL5 7PY, UK. mrees@ic.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11474101" target="_blank"〉PubMed〈/a〉

Description: An ecological community's species diversity tends to erode through time as a result of stochastic extinction, competitive exclusion, and unstable host-enemy dynamics. This erosion of diversity can be prevented over the short term if recruits are highly diverse as a result of preferential recruitment of rare species or, alternatively, if rare species survive preferentially, which increases diversity as the ages of the individuals increase. Here, we present census data from seven New and Old World tropical forest dynamics plots that all show the latter pattern. Within local areas, the trees that survived were as a group more diverse than those that were recruited or those that died. The larger (and therefore on average older) survivors were more diverse within local areas than the smaller survivors. When species were rare in a local area, they had a higher survival rate than when they were common, resulting in enrichment for rare species and increasing diversity with age and size class in these complex ecosystems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wills, Christopher -- Harms, Kyle E -- Condit, Richard -- King, David -- Thompson, Jill -- He, Fangliang -- Muller-Landau, Helene C -- Ashton, Peter -- Losos, Elizabeth -- Comita, Liza -- Hubbell, Stephen -- Lafrankie, James -- Bunyavejchewin, Sarayudh -- Dattaraja, H S -- Davies, Stuart -- Esufali, Shameema -- Foster, Robin -- Gunatilleke, Nimal -- Gunatilleke, Savitri -- Hall, Pamela -- Itoh, Akira -- John, Robert -- Kiratiprayoon, Somboon -- de Lao, Suzanne Loo -- Massa, Marie -- Nath, Cheryl -- Noor, Md Nur Supardi -- Kassim, Abdul Rahman -- Sukumar, Raman -- Suresh, Hebbalalu Satyanarayana -- Sun, I-Fang -- Tan, Sylvester -- Yamakura, Takuo -- Zimmerman, Jess -- New York, N.Y. -- Science. 2006 Jan 27;311(5760):527-31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0116, USA. cwills@ucsd.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16439661" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Svenning, Jens-Christian -- Condit, Richard -- New York, N.Y. -- Science. 2008 Oct 10;322(5899):206-7. doi: 10.1126/science.1164542.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Aarhus, Ny Munkegade 1540, 8000 Aarhus C, Denmark. svenning@biology.au.dk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18845738" target="_blank"〉PubMed〈/a〉

Description: The high alpha-diversity of tropical forests has been amply documented, but beta-diversity-how species composition changes with distance-has seldom been studied. We present quantitative estimates of beta-diversity for tropical trees by comparing species composition of plots in lowland terra firme forest in Panama, Ecuador, and Peru. We compare observations with predictions derived from a neutral model in which habitat is uniform and only dispersal and speciation influence species turnover. We find that beta-diversity is higher in Panama than in western Amazonia and that patterns in both areas are inconsistent with the neutral model. In Panama, habitat variation appears to increase species turnover relative to Amazonia, where unexpectedly low turnover over great distances suggests that population densities of some species are bounded by as yet unidentified processes. At intermediate scales in both regions, observations can be matched by theory, suggesting that dispersal limitation, with speciation, influences species turnover.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Condit, Richard -- Pitman, Nigel -- Leigh, Egbert G Jr -- Chave, Jerome -- Terborgh, John -- Foster, Robin B -- Nunez, Percy -- Aguilar, Salomon -- Valencia, Renato -- Villa, Gorky -- Muller-Landau, Helene C -- Losos, Elizabeth -- Hubbell, Stephen P -- New York, N.Y. -- Science. 2002 Jan 25;295(5555):666-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Unit 0948, APO AA 34002-0948, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11809969" target="_blank"〉PubMed〈/a〉

Description: Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stephenson, N L -- Das, A J -- Condit, R -- Russo, S E -- Baker, P J -- Beckman, N G -- Coomes, D A -- Lines, E R -- Morris, W K -- Ruger, N -- Alvarez, E -- Blundo, C -- Bunyavejchewin, S -- Chuyong, G -- Davies, S J -- Duque, A -- Ewango, C N -- Flores, O -- Franklin, J F -- Grau, H R -- Hao, Z -- Harmon, M E -- Hubbell, S P -- Kenfack, D -- Lin, Y -- Makana, J-R -- Malizia, A -- Malizia, L R -- Pabst, R J -- Pongpattananurak, N -- Su, S-H -- Sun, I-F -- Tan, S -- Thomas, D -- van Mantgem, P J -- Wang, X -- Wiser, S K -- Zavala, M A -- England -- Nature. 2014 Mar 6;507(7490):90-3. doi: 10.1038/nature12914. Epub 2014 Jan 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉US Geological Survey, Western Ecological Research Center, Three Rivers, California 93271, USA. ; Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama. ; School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA. ; Department of Forest and Ecosystem Science, University of Melbourne, Victoria 3121, Australia. ; 1] School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA [2] Mathematical Biosciences Institute, Ohio State University, Columbus, Ohio 43210, USA (N.G.B.); German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, 04103 Leipzig, Germany (N.R.). ; Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK. ; Department of Geography, University College London, London WC1E 6BT, UK. ; School of Botany, University of Melbourne, Victoria 3010, Australia. ; 1] Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama [2] Spezielle Botanik und Funktionelle Biodiversitat, Universitat Leipzig, 04103 Leipzig, Germany [3] Mathematical Biosciences Institute, Ohio State University, Columbus, Ohio 43210, USA (N.G.B.); German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, 04103 Leipzig, Germany (N.R.). ; Jardin Botanico de Medellin, Calle 73, No. 51D-14, Medellin, Colombia. ; Instituto de Ecologia Regional, Universidad Nacional de Tucuman, 4107 Yerba Buena, Tucuman, Argentina. ; Research Office, Department of National Parks, Wildlife and Plant Conservation, Bangkok 10900, Thailand. ; Department of Botany and Plant Physiology, Buea, Southwest Province, Cameroon. ; Smithsonian Institution Global Earth Observatory-Center for Tropical Forest Science, Smithsonian Institution, PO Box 37012, Washington, DC 20013, USA. ; Universidad Nacional de Colombia, Departamento de Ciencias Forestales, Medellin, Colombia. ; Wildlife Conservation Society, Kinshasa/Gombe, Democratic Republic of the Congo. ; Unite Mixte de Recherche-Peuplements Vegetaux et Bioagresseurs en Milieu Tropical, Universite de la Reunion/CIRAD, 97410 Saint Pierre, France. ; School of Environmental and Forest Sciences, University of Washington, Seattle, Washington 98195, USA. ; State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China. ; Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon 97331, USA. ; 1] Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama [2] Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095, USA. ; Department of Life Science, Tunghai University, Taichung City 40704, Taiwan. ; Facultad de Ciencias Agrarias, Universidad Nacional de Jujuy, 4600 San Salvador de Jujuy, Argentina. ; Faculty of Forestry, Kasetsart University, ChatuChak Bangkok 10900, Thailand. ; Taiwan Forestry Research Institute, Taipei 10066, Taiwan. ; Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien 97401, Taiwan. ; Sarawak Forestry Department, Kuching, Sarawak 93660, Malaysia. ; Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA. ; US Geological Survey, Western Ecological Research Center, Arcata, California 95521, USA. ; Landcare Research, PO Box 40, Lincoln 7640, New Zealand. ; Forest Ecology and Restoration Group, Department of Life Sciences, University of Alcala, Alcala de Henares, 28805 Madrid, Spain.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24429523" target="_blank"〉PubMed〈/a〉

Description: Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Condit, Richard -- Ashton, Peter -- Bunyavejchewin, Sarayudh -- Dattaraja, H S -- Davies, Stuart -- Esufali, Shameema -- Ewango, Corneille -- Foster, Robin -- Gunatilleke, I A U N -- Gunatilleke, C V S -- Hall, Pamela -- Harms, Kyle E -- Hart, Terese -- Hernandez, Consuelo -- Hubbell, Stephen -- Itoh, Akira -- Kiratiprayoon, Somboon -- Lafrankie, James -- de Lao, Suzanne Loo -- Makana, Jean-Remy -- Noor, Md Nur Supardi -- Kassim, Abdul Rahman -- Russo, Sabrina -- Sukumar, Raman -- Samper, Cristian -- Suresh, Hebbalalu S -- Tan, Sylvester -- Thomas, Sean -- Valencia, Renato -- Vallejo, Martha -- Villa, Gorky -- Zillio, Tommaso -- New York, N.Y. -- Science. 2006 Jul 7;313(5783):98-101. Epub 2006 Jun 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Center for Ecological Analysis and Synthesis, 735 State Street, Santa Barbara, CA 93101, USA. condit@ctfs.si.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16763113" target="_blank"〉PubMed〈/a〉