Assessing Evidence for a Pervasive Alteration in Tropical Tree Communities

• DOI: 10.1371/journal.pbio.0060045
• Publication Date: 2008-02-29T18:01:04Z
• Authors: Jérôme Chave; Richard Condit; Helene C Muller-L...; Sean C Thomas; Peter S Ashton; Sarayudh Bunyavej...; Leonardo L Co; Handanakere S Dat...; Stuart J Davies; Shameema Esufali; Corneille E. N Ew...; Kenneth J Feeley; Robin B Foster; Nimal Gunatilleke; Savitri Gunatilleke; Pamela Hall; Terese B Hart; Consuelo Hernández; Stephen P Hubbell; Akira Itoh; Somboon Kiratipra...; James V LaFrankie; Suzanne Loo de Lao; Jean-Rémy Makana; Md. Nur Supardi Noor; Abdul Rahman Kassim; Cristián Samper; Raman Sukumar; Hebbalalu S Suresh; Sylvester Tan; Jill Thompson; Ma. Dolores C Tongco; Renato Valencia; Martha Vallejo; Gorky Villa; Takuo Yamakura; Jess K Zimmerman; Elizabeth C Losos
• Keywords: Global Change; Tropical climate; Forest plot

In Amazonian tropical forests, recent studies have reported increases in aboveground biomass and primary productivity, as well shifts plant species composition favouring fast-growing over slow-growing ones. This pervasive alteration of mature forests was attributed to global environmental change, such an increase atmospheric CO2 concentration, nutrient deposition, temperature, drought frequency, and/or irradiance. We used standardized, repeated measurements 2 million trees ten large (16-52 ha each) forest plots on three continents evaluate the generality these findings across forests. Aboveground increased at seven our plots, significantly so four showed a decrease single plot. Carbon accumulation pooled sites significant (+0.24 MgC ha(-1) y(-1), 95% confidence intervals [0.07, 0.39] y(-1)), but lower than previously for Amazonia. At which we had data multiple census intervals, found no concerted gain, conflict with productivity hypothesis. Over all fastest-growing quartile gained (+0.33 [0.09, 0.55] % y(-1)) compared tree community whole (+0.15 y(-1)); however, this trend due Biomass when calculated (+0.21 [0.02, 0.37] half individually. Our results do not support hypothesis that are consistently increasing dominance communities. Instead, they suggest may be simultaneously recovering from past disturbances affected by changes resource availability. More long-term necessary clarify contribution change functioning