title: Successional dynamics in Neotropical forests are as uncertain as they are predictable.
abstract: Although forest succession has traditionally been approached as a deterministic process, successional trajectories of vegetation change vary widely, even among nearby stands with similar environmental conditions and disturbance histories. Here, we provide the first attempt, to our knowledge, to quantify predictability and uncertainty during succession based on the most extensive long-term datasets ever assembled for Neotropical forests. We develop a novel approach that integrates deterministic and stochastic components into different candidate models describing the dynamical interactions among three widely used and interrelated forest attributes--stem density, basal area, and species density. Within each of the seven study sites, successional trajectories were highly idiosyncratic, even when controlling for prior land use, environment, and initial conditions in these attributes. Plot factors were far more important than stand age in explaining successional trajectories. For each site, the best-fit model was able to capture the complete set of time series in certain attributes only when both the deterministic and stochastic components were set to similar magnitudes. Surprisingly, predictability of stem density, basal area, and species density did not show consistent trends across attributes, study sites, or land use history, and was independent of plot size and time series length. The model developed here represents the best approach, to date, for characterizing autogenic successional dynamics and demonstrates the low predictability of successional trajectories. These high levels of uncertainty suggest that the impacts of allogenic factors on rates of change during tropical forest succession are far more pervasive than previously thought, challenging the way ecologists view and investigate forest regeneration.
authors.affiliation: Fundación Cedrela, Bogotá 111311, Colombia; Departamento de Ecología y Territorio, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; natnorden@gmail.com.
authors.forename: Natalia
authors.initials: N
authors.lastname: Norden
authors.affiliation: Departamento de Ecología y Territorio, Pontificia Universidad Javeriana, Bogotá 110231, Colombia;
authors.forename: Héctor A
authors.initials: HA
authors.lastname: Angarita
authors.affiliation: Forest Ecology and Forest Management Group, Department of Environmental Sciences, Wageningen University, 6700 AA Wageningen, The Netherlands;
authors.forename: Frans
authors.initials: F
authors.lastname: Bongers
authors.affiliation: Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia 58190, Michoacán, Mexico;
authors.forename: Miguel
authors.initials: M
authors.lastname: Martínez-Ramos
authors.affiliation: Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad Autónoma de Barcelona, E-08193 Bellaterra, Spain;
authors.forename: Iñigo
authors.initials: I
authors.lastname: Granzow-de la Cerda
authors.affiliation: Yale-National University of Singapore College, Singapore 138614; Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Panama;
authors.forename: Michiel
authors.initials: M
authors.lastname: van Breugel
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Panama; Department of Forest Resources, University of Minnesota, St. Paul, MN 55108;
authors.forename: Edwin
authors.initials: E
authors.lastname: Lebrija-Trejos
authors.affiliation: Facultad de Ciencias, Departamento de Ecología y Recursos Naturales, Universidad Nacional Autónoma de México, México 04510, DF, Mexico;
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Meave
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109;
authors.forename: John
authors.initials: J
authors.lastname: Vandermeer
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70808;
authors.forename: G Bruce
authors.initials: GB
authors.lastname: Williamson
authors.affiliation: Production and Conservation in Forests Program, Tropical Agricultural Centre for Research and Higher Education, Apartado 93-7170, Turrialba, Costa Rica;
authors.forename: Bryan
authors.initials: B
authors.lastname: Finegan
authors.affiliation: Biological Dynamics of Forest Fragments Project, Instituto Nacional de Pesquisas da Amazonia, Manaus, AM 69011-970, Brazil;
authors.forename: Rita
authors.initials: R
authors.lastname: Mesquita
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Chazdon
mesh_terms: D017753:Ecosystem; D065928:Forests; D013269:Stochastic Processes; D014329:Tropical Climate; D035501:Uncertainty
keywords: dynamical models; predictability; succession; tropical secondary forests; uncertainty