43 results on '"Norden N."'
Search Results
2. A Plea for Pure Church Music
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Norden, N. Lindsay
- Published
- 1918
Catalog
3. A Brief Study of the Russian Liturgy and Its Music
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Norden, N. Lindsay
- Published
- 1919
4. A New Theory of Untempered Music: A Few Important Features with Special Reference to "A Cappella" Music
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Norden, N. Lindsay
- Published
- 1936
5. Payoff dominance vs. cognitive transparency in decision making
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Irwin, Julie R., McClelland, Gary H., McKee, Michael, Schulze, William D., and Norden, N. Elizabeth
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Markets (Economics) -- Research -- Economic aspects ,Decision-making -- Economic aspects -- Research ,Business, general ,Economics ,Economic aspects ,Research - Abstract
This paper reports on three laboratory experiments designed to investigate the roles of decision costs and rewards on the accuracy of economic decisions. The experimental vehicle is a purchase decision employing the Becker-DeGroot-Marshak (BDM) mechanism. The first experiment verifies the incentive-compatibility of the BDM in a pure induced-value setting; the second tests its performance under different information regimes and payoff schedules; the third addresses the role of feedback information. Steep payoff schedules are found to be necessary to optimizing behavior only in cases where subjects must search out an optimal strategy rather than being able to deduce it from information provided., I. INTRODUCTION There is a general question about how well laboratory markets work in eliciting true preferences given the low opportunity costs of making errors as in Harrison [1989]. Vernon [...] more...
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- 1998
6. Payoff dominance vs. cognitive transparency in decision making.
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Irwon, Julie R., McClelland, Gary H., McKee, Michael, Schulze, William D., and Norden, N. Elizabeth
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DECISION making - Abstract
Reports on three laboratory experiments designed to investigate the roles of decision costs and rewards on the accuracy of economic decisions. Use of the Becker-DeGroot-Marshak mechanism (BDM); Incentive-compatibility of the BDM in a pure induced-value setting; Performance of the BDM under different information regimes and payoff schedules; Role of feedback information. more...
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- 1998
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7. METOPROLOL, FENTANYL AND STRESS RESPONSES TO MICROLARYNGOSCOPY: Effects on arterial pressure, heart rate and plasma concentrations of catecholamines, ACTH and cortisol
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MAGNUSSON, J., WERNER, O., CARLSSON, C., NORDÉN, N., and PETTERSSON, K.-I.
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- 1983
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8. INFLUENCE OF PREMEDICATION ON THE SYMPATHETIC AND ENDOCRINE RESPONESE AND CARDIAC ARRHYTMIAS DURING HALOTHANE ANAESTHESIA IN CHILDREN UNDERGOING ADENODIECTOMY
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SIGURDSSON, G.H., LINDAHL, S., and NORDÉN, N.
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- 1983
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9. Catecholamine and Endocrine Response in Children During Halothane and Enflurane Anesthesia for Adenoidectomy.
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Sigurdson, G. H., Lindahl, S. G. E., and Norden, N. E.
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- 1984
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10. SI (LI)-detector efficiencies characterized using x-ray intensity ratios
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Wahlberg, G., Wirmark, G., and Nordén, N.
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- 1986
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11. Errata
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Sigurdsson, G.H., Lindahl, S., and Nordén, N.
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- 1984
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12. Linking seedling wood anatomical trade-offs with drought and seedling growth and survival in tropical dry forests.
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González-Melo A, Salgado-Negret B, Norden N, González-M R, Benavides JP, Cely JM, Abad Ferrer J, Idárraga Á, Moreno E, Pizano C, Puentes-Marín J, Pulido N, Rivera K, Rojas-Bautista F, Solorzano JF, and Umaña MN more...
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- Water metabolism, Seedlings growth & development, Seedlings anatomy & histology, Seedlings physiology, Droughts, Wood growth & development, Wood anatomy & histology, Wood physiology, Forests, Tropical Climate
- Abstract
Wood anatomy plays a key role in plants' ability to persist under drought and should therefore predict demography. Plants balance their resource allocation among wood cell types responsible for different functions. However, it remains unclear how these anatomical trade-offs vary with water availability, and the extent to which they influence demographic rates. We investigated how wood anatomical trade-offs were related to drought and demographic rates, for seedling communities in four tropical dry forests differing in their aridity indexes (AIs). We measured wood density, as well as vessel, fiber and parenchyma traits of 65 species, and we monitored growth and survival for a 1-yr period. Two axes defined wood anatomical structure: a fiber-parenchyma axis and a vessel-wood density axis. Seedlings in drier sites had larger fiber but lower parenchyma fractions, while in less dry forests, seedlings had the opposite allocation pattern. The fiber-parenchyma trade-off was unrelated to growth but was positively related to survival, and this later relationship was mediated by the AI. These findings expand our knowledge about the wood anatomical trade-offs that mediate responses to drought conditions and influence demographic rates, in the seedling layer. This information is needed to anticipate future responses of forests to changing drought conditions., (© 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.) more...
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- 2025
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13. Tree demographic strategies largely overlap across succession in Neotropical wet and dry forest communities.
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Schorn ME, Kambach S, Chazdon RL, Craven D, Farrior CE, Meave JA, Muñoz R, van Breugel M, Amissah L, Bongers F, Hérault B, Jakovac CC, Norden N, Poorter L, van der Sande MT, Wirth C, Delgado D, Dent DH, DeWalt SJ, Dupuy JM, Finegan B, Hall JS, Hernández-Stefanoni JL, Lopez OR, and Rüger N more...
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- Panama, Mexico, Costa Rica, Biodiversity, Forests, Trees, Tropical Climate
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Secondary tropical forests play an increasingly important role in carbon budgets and biodiversity conservation. Understanding successional trajectories is therefore imperative for guiding forest restoration and climate change mitigation efforts. Forest succession is driven by the demographic strategies-combinations of growth, mortality and recruitment rates-of the tree species in the community. However, our understanding of demographic diversity in tropical tree species stems almost exclusively from old-growth forests. Here, we assembled demographic information from repeated forest inventories along chronosequences in two wet (Costa Rica, Panama) and two dry (Mexico) Neotropical forests to assess whether the ranges of demographic strategies present in a community shift across succession. We calculated demographic rates for >500 tree species while controlling for canopy status to compare demographic diversity (i.e., the ranges of demographic strategies) in early successional (0-30 years), late successional (30-120 years) and old-growth forests using two-dimensional hypervolumes of pairs of demographic rates. Ranges of demographic strategies largely overlapped across successional stages, and early successional stages already covered the full spectrum of demographic strategies found in old-growth forests. An exception was a group of species characterized by exceptionally high mortality rates that was confined to early successional stages in the two wet forests. The range of demographic strategies did not expand with succession. Our results suggest that studies of long-term forest monitoring plots in old-growth forests, from which most of our current understanding of demographic strategies of tropical tree species is derived, are surprisingly representative of demographic diversity in general, but do not replace the need for further studies in secondary forests., (© 2024 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.) more...
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- 2024
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14. Feedback loops drive ecological succession: towards a unified conceptual framework.
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van Breugel M, Bongers F, Norden N, Meave JA, Amissah L, Chanthorn W, Chazdon R, Craven D, Farrior C, Hall JS, Hérault B, Jakovac C, Lebrija-Trejos E, Martínez-Ramos M, Muñoz R, Poorter L, Rüger N, van der Sande M, and Dent DH more...
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- Plants, Models, Biological, Plant Development physiology, Ecosystem
- Abstract
The core principle shared by most theories and models of succession is that, following a major disturbance, plant-environment feedback dynamics drive a directional change in the plant community. The most commonly studied feedback loops are those in which the regrowth of the plant community causes changes to the abiotic (e.g. soil nutrients) or biotic (e.g. dispersers) environment, which differentially affect species availability or performance. This, in turn, leads to shifts in the species composition of the plant community. However, there are many other PE feedback loops that potentially drive succession, each of which can be considered a model of succession. While plant-environment feedback loops in principle generate predictable successional trajectories, succession is generally observed to be highly variable. Factors contributing to this variability are the stochastic processes involved in feedback dynamics, such as individual mortality and seed dispersal, and extrinsic causes of succession, which are not affected by changes in the plant community but do affect species performance or availability. Both can lead to variation in the identity of dominant species within communities. This, in turn, leads to further contingencies if these species differ in their effect on their environment (priority effects). Predictability and variability are thus intrinsically linked features of ecological succession. We present a new conceptual framework of ecological succession that integrates the propositions discussed above. This framework defines seven general causes: landscape context, disturbance and land-use, biotic factors, abiotic factors, species availability, species performance, and the plant community. When involved in a feedback loop, these general causes drive succession and when not, they are extrinsic causes that create variability in successional trajectories and dynamics. The proposed framework provides a guide for linking these general causes into causal pathways that represent specific models of succession. Our framework represents a systematic approach to identifying the main feedback processes and causes of variation at different successional stages. It can be used for systematic comparisons among study sites and along environmental gradients, to conceptualise studies, and to guide the formulation of research questions and design of field studies. Mapping an extensive field study onto our conceptual framework revealed that the pathways representing the study's empirical outcomes and conceptual model had important differences, underlining the need to move beyond the conceptual models that currently dominate in specific fields and to find ways to examine the importance of and interactions among alternative causal pathways of succession. To further this aim, we argue for integrating long-term studies across environmental and anthropogenic gradients, combined with controlled experiments and dynamic modelling., (© 2024 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.) more...
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- 2024
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15. Latitudinal patterns in stabilizing density dependence of forest communities.
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Hülsmann L, Chisholm RA, Comita L, Visser MD, de Souza Leite M, Aguilar S, Anderson-Teixeira KJ, Bourg NA, Brockelman WY, Bunyavejchewin S, Castaño N, Chang-Yang CH, Chuyong GB, Clay K, Davies SJ, Duque A, Ediriweera S, Ewango C, Gilbert GS, Holík J, Howe RW, Hubbell SP, Itoh A, Johnson DJ, Kenfack D, Král K, Larson AJ, Lutz JA, Makana JR, Malhi Y, McMahon SM, McShea WJ, Mohamad M, Nasardin M, Nathalang A, Norden N, Oliveira AA, Parmigiani R, Perez R, Phillips RP, Pongpattananurak N, Sun IF, Swanson ME, Tan S, Thomas D, Thompson J, Uriarte M, Wolf AT, Yao TL, Zimmerman JK, Zuleta D, and Hartig F more...
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- Models, Biological, Species Specificity, Tropical Climate, Biodiversity, Forests, Geographic Mapping, Trees classification, Trees physiology
- Abstract
Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species
1,2 , a phenomenon known as conspecific negative density dependence (CNDD)3 . A long-held ecological hypothesis posits that CNDD is more pronounced in tropical than in temperate forests4,5 , which increases community stabilization, species coexistence and the diversity of local tree species6,7 . Previous analyses supporting such a latitudinal gradient in CNDD8,9 have suffered from methodological limitations related to the use of static data10-12 . Here we present a comprehensive assessment of latitudinal CNDD patterns using dynamic mortality data to estimate species-site-specific CNDD across 23 sites. Averaged across species, we found that stabilizing CNDD was present at all except one site, but that average stabilizing CNDD was not stronger toward the tropics. However, in tropical tree communities, rare and intermediate abundant species experienced stronger stabilizing CNDD than did common species. This pattern was absent in temperate forests, which suggests that CNDD influences species abundances more strongly in tropical forests than it does in temperate ones13 . We also found that interspecific variation in CNDD, which might attenuate its stabilizing effect on species diversity14,15 , was high but not significantly different across latitudes. Although the consequences of these patterns for latitudinal diversity gradients are difficult to evaluate, we speculate that a more effective regulation of population abundances could translate into greater stabilization of tropical tree communities and thus contribute to the high local diversity of tropical forests., (© 2024. The Author(s).) more...- Published
- 2024
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16. Upscaling the effect of traits in response to drought: The relative importance of safety-efficiency and acquisitive-conservation functional axes.
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Umaña MN, Salgado-Negret B, Norden N, Salinas V, Garzón F, Medina SP, Rodríguez-M GM, López-Camacho R, Castaño-Naranjo A, Cuadros H, Franke-Ante R, Avella A, Idárraga-Piedrahita Á, Jurado R, Nieto J, Pizano C, Torres AM, García H, and González-M R more...
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- Humans, Forests, Trees physiology, Wood, Plant Leaves, Droughts, Tropical Climate
- Abstract
We tested the idea that functional trade-offs that underlie species tolerance to drought-driven shifts in community composition via their effects on demographic processes and subsequently on shifts in species' abundance. Using data from 298 tree species from tropical dry forests during the extreme ENSO-2015, we scaled-up the effects of trait trade-offs from individuals to communities. Conservative wood and leaf traits favoured slow tree growth, increased tree survival and positively impacted species abundance and dominance at the community-level. Safe hydraulic traits, on the other hand, were related to demography but did not affect species abundance and communities. The persistent effects of the conservative-acquisitive trade-off across organizational levels is promising for generalization and predictability of tree communities. However, the safety-efficient trade-off showed more intricate effects on performance. Our results demonstrated the complex pathways in which traits scale up to communities, highlighting the importance of considering a wide range of traits and performance processes., (© 2023 The Authors. Ecology Letters published by John Wiley & Sons Ltd.) more...
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- 2023
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17. Mycorrhizal feedbacks influence global forest structure and diversity.
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Delavaux CS, LaManna JA, Myers JA, Phillips RP, Aguilar S, Allen D, Alonso A, Anderson-Teixeira KJ, Baker ME, Baltzer JL, Bissiengou P, Bonfim M, Bourg NA, Brockelman WY, Burslem DFRP, Chang LW, Chen Y, Chiang JM, Chu C, Clay K, Cordell S, Cortese M, den Ouden J, Dick C, Ediriweera S, Ellis EC, Feistner A, Freestone AL, Giambelluca T, Giardina CP, Gilbert GS, He F, Holík J, Howe RW, Huaraca Huasca W, Hubbell SP, Inman F, Jansen PA, Johnson DJ, Kral K, Larson AJ, Litton CM, Lutz JA, Malhi Y, McGuire K, McMahon SM, McShea WJ, Memiaghe H, Nathalang A, Norden N, Novotny V, O'Brien MJ, Orwig DA, Ostertag R, Parker GG', Pérez R, Reynolds G, Russo SE, Sack L, Šamonil P, Sun IF, Swanson ME, Thompson J, Uriarte M, Vandermeer J, Wang X, Ware I, Weiblen GD, Wolf A, Wu SH, Zimmerman JK, Lauber T, Maynard DS, Crowther TW, and Averill C more...
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- Feedback, Symbiosis, Plants microbiology, Soil, Mycorrhizae
- Abstract
One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fungi, which may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree species exhibit weaker negative CDD than arbuscular mycorrhizal tree species. We further tested for conmycorrhizal density dependence (CMDD) to test for benefit from shared mutualists. We found that the strength of CDD varies systematically with mycorrhizal type, with ectomycorrhizal tree species exhibiting higher sapling densities with increasing adult densities than arbuscular mycorrhizal tree species. Moreover, we found evidence of positive CMDD for tree species of both mycorrhizal types. Collectively, these findings indicate that mycorrhizal interactions likely play a foundational role in global forest diversity patterns and structure., (© 2023. Springer Nature Limited.) more...
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- 2023
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18. Causality Network of Infectious Disease Revealed With Causal Decomposition.
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Sun J, Yuan K, Chen C, Xu H, Wang H, Zhi Y, Peng S, Peng CK, Huang N, Huang G, and Yang A
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- Humans, Causality, Risk Factors, Communicable Diseases epidemiology
- Abstract
Causal inference in the field of infectious disease attempts to gain insight into the potential causal nature of an association between risk factors and diseases. Simulated causality inference experiments have shown preliminary promise in improving understanding of the transmission of infectious diseases but still lack sufficient quantitative causal inference studies based on real-world data. Here, we investigate the causal interactions between three different infectious diseases and related factors, using causal decomposition analysis, to characterize the nature of infectious disease transmission. We show that the complex interactions between infectious disease and human behavior have a quantifiable impact on transmission efficiency of infectious diseases. Our findings, by shedding light on the underlying transmission mechanism of infectious diseases, suggest that causal inference analysis is a promising approach to determine epidemiological interventions. more...
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- 2023
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19. Soil resistance and recovery during neotropical forest succession.
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van der Sande MT, Powers JS, Kuyper TW, Norden N, Salgado-Negret B, Silva de Almeida J, Bongers F, Delgado D, Dent DH, Derroire G, do Espirito Santo MM, Dupuy JM, Fernandes GW, Finegan B, Gavito ME, Hernández-Stefanoni JL, Jakovac CC, Jones IL, das Dores Magalhães Veloso M, Meave JA, Mora F, Muñoz R, Pérez-Cárdenas N, Piotto D, Álvarez-Dávila E, Caceres-Siani Y, Dalban-Pilon C, Dourdain A, Du DV, García Villalobos D, Nunes YRF, Sanchez-Azofeifa A, and Poorter L more...
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- Clay, Forests, Carbon, Soil chemistry, Ecosystem
- Abstract
The recovery of soil conditions is crucial for successful ecosystem restoration and, hence, for achieving the goals of the UN Decade on Ecosystem Restoration. Here, we assess how soils resist forest conversion and agricultural land use, and how soils recover during subsequent tropical forest succession on abandoned agricultural fields. Our overarching question is how soil resistance and recovery depend on local conditions such as climate, soil type and land-use history. For 300 plots in 21 sites across the Neotropics, we used a chronosequence approach in which we sampled soils from two depths in old-growth forests, agricultural fields (i.e. crop fields and pastures), and secondary forests that differ in age (1-95 years) since abandonment. We measured six soil properties using a standardized sampling design and laboratory analyses. Soil resistance strongly depended on local conditions. Croplands and sites on high-activity clay (i.e. high fertility) show strong increases in bulk density and decreases in pH, carbon (C) and nitrogen (N) during deforestation and subsequent agricultural use. Resistance is lower in such sites probably because of a sharp decline in fine root biomass in croplands in the upper soil layers, and a decline in litter input from formerly productive old-growth forest (on high-activity clays). Soil recovery also strongly depended on local conditions. During forest succession, high-activity clays and croplands decreased most strongly in bulk density and increased in C and N, possibly because of strongly compacted soils with low C and N after cropland abandonment, and because of rapid vegetation recovery in high-activity clays leading to greater fine root growth and litter input. Furthermore, sites at low precipitation decreased in pH, whereas sites at high precipitation increased in N and decreased in C : N ratio. Extractable phosphorus (P) did not recover during succession, suggesting increased P limitation as forests age. These results indicate that no single solution exists for effective soil restoration and that local site conditions should determine the restoration strategies. This article is part of the theme issue 'Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'. more...
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- 2023
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20. Monitoring recovery of tree diversity during tropical forest restoration: lessons from long-term trajectories of natural regeneration.
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Chazdon RL, Norden N, Colwell RK, and Chao A
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- Forests, Costa Rica, Tropical Climate, Biodiversity, Trees, Ecosystem
- Abstract
Given the importance of species diversity as a tool for assessing recovery during forest regeneration and active restoration, robust approaches for assessing changes in tree species diversity over time are urgently needed. We assessed changes in tree species diversity during natural regeneration over 12-20 years in eight 1-ha monitoring plots in NE Costa Rica, six second-growth forests and two old-growth reference forests. We used diversity profiles to show successional trajectories in measures of observed, asymptotic and standardized tree diversity and evenness as well as sample completeness. We randomly subsampled 1-ha plot data to evaluate how well smaller spatial subsamples would have captured temporal trajectories. Annual surveys in eight 1-ha plots were missing substantial numbers of rare or infrequent species. Older second-growth sites showed consistent declines in tree diversity, whereas younger sites showed fluctuating patterns or increases. Subsample areas of 0.5 ha or greater were sufficient to infer the diversity of abundant species, but smaller subsamples failed to capture temporal trajectories of species richness and yielded positively biased estimates of evenness. In tropical forest regions with high levels of diversity, species diversity from small sample plots should be assessed using methods that incorporate abundance information and that standardize for sample coverage. This article is part of the theme issue 'Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'. more...
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- 2023
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21. FunAndes - A functional trait database of Andean plants.
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Báez S, Cayuela L, Macía MJ, Álvarez-Dávila E, Apaza-Quevedo A, Arnelas I, Baca-Cortes N, Bañares de Dios G, Bauters M, Ben Saadi C, Blundo C, Cabrera M, Castaño F, Cayola L, de Aledo JG, Espinosa CI, Fadrique B, Farfán-Rios W, Fuentes A, Garnica-Díaz C, González M, González D, Hensen I, Hurtado AB, Jadán O, Lippok D, Loza MI, Maldonado C, Malizia L, Matas-Granados L, Myers JA, Norden N, Oliveras Menor I, Pierick K, Ramírez-Angulo H, Salgado-Negret B, Schleuning M, Silman M, Solarte-Cruz ME, Tello JS, Verbeeck H, Vilanova E, Weithmann G, and Homeier J more...
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- Phenotype, Plant Leaves, Wood, Biodiversity, Plants
- Abstract
We introduce the FunAndes database, a compilation of functional trait data for the Andean flora spanning six countries. FunAndes contains data on 24 traits across 2,694 taxa, for a total of 105,466 entries. The database features plant-morphological attributes including growth form, and leaf, stem, and wood traits measured at the species or individual level, together with geographic metadata (i.e., coordinates and elevation). FunAndes follows the field names, trait descriptions and units of measurement of the TRY database. It is currently available in open access in the FIGSHARE data repository, and will be part of TRY's next release. Open access trait data from Andean plants will contribute to ecological research in the region, the most species rich terrestrial biodiversity hotspot., (© 2022. The Author(s).) more...
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- 2022
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22. Functional susceptibility of tropical forests to climate change.
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Aguirre-Gutiérrez J, Berenguer E, Oliveras Menor I, Bauman D, Corral-Rivas JJ, Nava-Miranda MG, Both S, Ndong JE, Ondo FE, Bengone NN, Mihinhou V, Dalling JW, Heineman K, Figueiredo A, González-M R, Norden N, Hurtado-M AB, González D, Salgado-Negret B, Reis SM, Moraes de Seixas MM, Farfan-Rios W, Shenkin A, Riutta T, Girardin CAJ, Moore S, Abernethy K, Asner GP, Bentley LP, Burslem DFRP, Cernusak LA, Enquist BJ, Ewers RM, Ferreira J, Jeffery KJ, Joly CA, Marimon-Junior BH, Martin RE, Morandi PS, Phillips OL, Bennett AC, Lewis SL, Quesada CA, Marimon BS, Kissling WD, Silman M, Teh YA, White LJT, Salinas N, Coomes DA, Barlow J, Adu-Bredu S, and Malhi Y more...
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- Forests, Trees, Water, Climate Change, Ecosystem
- Abstract
Tropical forests are some of the most biodiverse ecosystems in the world, yet their functioning is threatened by anthropogenic disturbances and climate change. Global actions to conserve tropical forests could be enhanced by having local knowledge on the forests' functional diversity and functional redundancy as proxies for their capacity to respond to global environmental change. Here we create estimates of plant functional diversity and redundancy across the tropics by combining a dataset of 16 morphological, chemical and photosynthetic plant traits sampled from 2,461 individual trees from 74 sites distributed across four continents together with local climate data for the past half century. Our findings suggest a strong link between climate and functional diversity and redundancy with the three trait groups responding similarly across the tropics and climate gradient. We show that drier tropical forests are overall less functionally diverse than wetter forests and that functional redundancy declines with increasing soil water and vapour pressure deficits. Areas with high functional diversity and high functional redundancy tend to better maintain ecosystem functioning, such as aboveground biomass, after extreme weather events. Our predictions suggest that the lower functional diversity and lower functional redundancy of drier tropical forests, in comparison with wetter forests, may leave them more at risk of shifting towards alternative states in face of further declines in water availability across tropical regions., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.) more...
- Published
- 2022
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23. Strong floristic distinctiveness across Neotropical successional forests.
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Jakovac CC, Meave JA, Bongers F, Letcher SG, Dupuy JM, Piotto D, Rozendaal DMA, Peña-Claros M, Craven D, Santos BA, Siminski A, Fantini AC, Rodrigues AC, Hernández-Jaramillo A, Idárraga A, Junqueira AB, Zambrano AMA, de Jong BHJ, Pinho BX, Finegan B, Castellano-Castro C, Zambiazi DC, Dent DH, García DH, Kennard D, Delgado D, Broadbent EN, Ortiz-Malavassi E, Pérez-García EA, Lebrija-Trejos E, Berenguer E, Marín-Spiotta E, Alvarez-Davila E, de Sá Sampaio EV, Melo F, Elias F, França F, Oberleitner F, Mora F, Williamson GB, Colletta GD, Cabral GAL, Derroire G, Fernandes GW, van der Wal H, Teixeira HM, Vester HFM, García H, Vieira ICG, Jiménez-Montoya J, de Almeida-Cortez JS, Hall JS, Chave J, Zimmerman JK, Nieto JE, Ferreira J, Rodríguez-Velázquez J, Ruíz J, Barlow J, Aguilar-Cano J, Hernández-Stefanoni JL, Engel J, Becknell JM, Zanini K, Lohbeck M, Tabarelli M, Romero-Romero MA, Uriarte M, Veloso MDM, Espírito-Santo MM, van der Sande MT, van Breugel M, Martínez-Ramos M, Schwartz NB, Norden N, Pérez-Cárdenas N, González-Valdivia N, Petronelli P, Balvanera P, Massoca P, Brancalion PHS, Villa PM, Hietz P, Ostertag R, López-Camacho R, César RG, Mesquita R, Chazdon RL, Muñoz R, DeWalt SJ, Müller SC, Durán SM, Martins SV, Ochoa-Gaona S, Rodríguez-Buritica S, Aide TM, Bentos TV, de S Moreno V, Granda V, Thomas W, Silver WL, Nunes YRF, and Poorter L more...
- Abstract
Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained. more...
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- 2022
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24. Demographic composition, not demographic diversity, predicts biomass and turnover across temperate and tropical forests.
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Needham JF, Johnson DJ, Anderson-Teixeira KJ, Bourg N, Bunyavejchewin S, Butt N, Cao M, Cárdenas D, Chang-Yang CH, Chen YY, Chuyong G, Dattaraja HS, Davies SJ, Duque A, Ewango CEN, Fernando ES, Fisher R, Fletcher CD, Foster R, Hao Z, Hart T, Hsieh CF, Hubbell SP, Itoh A, Kenfack D, Koven CD, Larson AJ, Lutz JA, McShea W, Makana JR, Malhi Y, Marthews T, Bt Mohamad M, Morecroft MD, Norden N, Parker G, Shringi A, Sukumar R, Suresh HS, Sun IF, Tan S, Thomas DW, Thompson J, Uriarte M, Valencia R, Yao TL, Yap SL, Yuan Z, Yuehua H, Zimmerman JK, Zuleta D, and McMahon SM more...
- Subjects
- Biomass, Demography, Ecosystem, Climate Change, Tropical Climate
- Abstract
The growth and survival of individual trees determine the physical structure of a forest with important consequences for forest function. However, given the diversity of tree species and forest biomes, quantifying the multitude of demographic strategies within and across forests and the way that they translate into forest structure and function remains a significant challenge. Here, we quantify the demographic rates of 1961 tree species from temperate and tropical forests and evaluate how demographic diversity (DD) and demographic composition (DC) differ across forests, and how these differences in demography relate to species richness, aboveground biomass (AGB), and carbon residence time. We find wide variation in DD and DC across forest plots, patterns that are not explained by species richness or climate variables alone. There is no evidence that DD has an effect on either AGB or carbon residence time. Rather, the DC of forests, specifically the relative abundance of large statured species, predicted both biomass and carbon residence time. Our results demonstrate the distinct DCs of globally distributed forests, reflecting biogeography, recent history, and current plot conditions. Linking the DC of forests to resilience or vulnerability to climate change, will improve the precision and accuracy of predictions of future forest composition, structure, and function., (© 2022 John Wiley & Sons Ltd.) more...
- Published
- 2022
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25. Discovering the forest in plain sight: a pop-up Symposium focusing on seasonally dry tropical forests.
- Author
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Powers JS, Mondragón-Botero A, Norden N, Salgado-Negret B, Pizano C, Gonzalez-M R, and Vargas G G
- Subjects
- Trees, Forests, Tropical Climate
- Published
- 2022
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26. Multidimensional tropical forest recovery.
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Poorter L, Craven D, Jakovac CC, van der Sande MT, Amissah L, Bongers F, Chazdon RL, Farrior CE, Kambach S, Meave JA, Muñoz R, Norden N, Rüger N, van Breugel M, Almeyda Zambrano AM, Amani B, Andrade JL, Brancalion PHS, Broadbent EN, de Foresta H, Dent DH, Derroire G, DeWalt SJ, Dupuy JM, Durán SM, Fantini AC, Finegan B, Hernández-Jaramillo A, Hernández-Stefanoni JL, Hietz P, Junqueira AB, N'dja JK, Letcher SG, Lohbeck M, López-Camacho R, Martínez-Ramos M, Melo FPL, Mora F, Müller SC, N'Guessan AE, Oberleitner F, Ortiz-Malavassi E, Pérez-García EA, Pinho BX, Piotto D, Powers JS, Rodríguez-Buriticá S, Rozendaal DMA, Ruíz J, Tabarelli M, Teixeira HM, Valadares de Sá Barretto Sampaio E, van der Wal H, Villa PM, Fernandes GW, Santos BA, Aguilar-Cano J, de Almeida-Cortez JS, Alvarez-Davila E, Arreola-Villa F, Balvanera P, Becknell JM, Cabral GAL, Castellanos-Castro C, de Jong BHJ, Nieto JE, Espírito-Santo MM, Fandino MC, García H, García-Villalobos D, Hall JS, Idárraga A, Jiménez-Montoya J, Kennard D, Marín-Spiotta E, Mesquita R, Nunes YRF, Ochoa-Gaona S, Peña-Claros M, Pérez-Cárdenas N, Rodríguez-Velázquez J, Villanueva LS, Schwartz NB, Steininger MK, Veloso MDM, Vester HFM, Vieira ICG, Williamson GB, Zanini K, and Hérault B more...
- Abstract
Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (<1 decade) and plant functioning (<2.5 decades), intermediate for structure and species diversity (2.5 to 6 decades), and slowest for biomass and species composition (>12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation. more...
- Published
- 2021
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27. Within-cycle instantaneous frequency profiles report oscillatory waveform dynamics.
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Quinn AJ, Lopes-Dos-Santos V, Huang N, Liang WK, Juan CH, Yeh JR, Nobre AC, Dupret D, and Woolrich MW
- Subjects
- Animals, Mice, Theta Rhythm physiology, Brain Waves physiology, CA1 Region, Hippocampal physiology, Electroencephalography methods, Signal Processing, Computer-Assisted
- Abstract
The nonsinusoidal waveform is emerging as an important feature of neuronal oscillations. However, the role of single-cycle shape dynamics in rapidly unfolding brain activity remains unclear. Here, we develop an analytical framework that isolates oscillatory signals from time series using masked empirical mode decomposition to quantify dynamical changes in the shape of individual cycles (along with amplitude, frequency, and phase) with instantaneous frequency. We show how phase-alignment, a process of projecting cycles into a regularly sampled phase grid space, makes it possible to compare cycles of different durations and shapes. "Normalized shapes" can then be constructed with high temporal detail while accounting for differences in both duration and amplitude. We find that the instantaneous frequency tracks nonsinusoidal shapes in both simulated and real data. Notably, in local field potential recordings of mouse hippocampal CA1, we find that theta oscillations have a stereotyped slow-descending slope in the cycle-wise average yet exhibit high variability on a cycle-by-cycle basis. We show how principal component analysis allows identification of motifs of theta cycle waveform that have distinct associations to cycle amplitude, cycle duration, and animal movement speed. By allowing investigation into oscillation shape at high temporal resolution, this analytical framework will open new lines of inquiry into how neuronal oscillations support moment-by-moment information processing and integration in brain networks. NEW & NOTEWORTHY We propose a novel analysis approach quantifying nonsinusoidal waveform shape. The approach isolates oscillations with empirical mode decomposition before waveform shape is quantified using phase-aligned instantaneous frequency. This characterizes the full shape profile of individual cycles while accounting for between-cycle differences in duration, amplitude, and timing. We validated in simulations before applying to identify a range of data-driven nonsinusoidal shape motifs in hippocampal theta oscillations. more...
- Published
- 2021
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- View/download PDF
28. Cardiac involvement in critically ill and mechanically ventilated patients with COVID-19 - a prospective, observational echocardiographic study.
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Norden N, Lundin EO, Hagberg E, Gao SA, Hård Af Segerstad M, Nellgård B, and Dalla K
- Abstract
Introduction: In this prospective, observational study, we have evaluated right (RV) and left (LV) ventricular function with echocardiography and correlated it to the levels of biomarkers, hs-TNT, NT-pro-BNP, D-dimer and fibrinogen. In a subgroup, we have evaluated the effect of inhaled milrinone on RV afterload and function., Methods: Thirty-one ICU patients with COVID-19 in need of mechanical ventilation and norepinephrine infusion were prospectively included. Hemodynamic and respiratory variables were measured at the time of the echocardiographic examination and biomarkers were obtained on arrival at the ICU and then followed up routinely. Eight patients received inhaled aerosolized milrinone at a dose of 2.5 mg/hour., Results: The most common echocardiographic pattern was RV dilation with or without systolic dysfunction, which was found in 62% of patients. Pulmonary acceleration time was abnormal in 55% and indices of RV systolic function, such as fractional area of change, RV strain, were abnormal in 30% and 31% of patients respectively. A cardiac index of < 2.5 l/min*m
2 was seen in 58% of the patients. Left ventricular ejection fraction and global left ventricular strain were impaired in 10% and 16% respectively. The correlation between echocardiographic variables and cardiac biomarkers was poor. RV afterload correlated well to the levels of D-dimer. Milrinone inhalation did not improve RV function or afterload., Conclusion: RV dysfunction was the most common finding. The poor correlation to cardiac biomarkers argues against extensive myocardial involvement. The lack of improvement in RV function after milrinone inhalation suggests that the most likely cause of RV dysfunction is increased RV afterload caused by pulmonary thrombosis/embolism., Competing Interests: None., (AJCD Copyright © 2021.) more...- Published
- 2021
29. Diverging functional strategies but high sensitivity to an extreme drought in tropical dry forests.
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González-M R, Posada JM, Carmona CP, Garzón F, Salinas V, Idárraga-Piedrahita Á, Pizano C, Avella A, López-Camacho R, Norden N, Nieto J, Medina SP, Rodríguez-M GM, Franke-Ante R, Torres AM, Jurado R, Cuadros H, Castaño-Naranjo A, García H, and Salgado-Negret B more...
- Subjects
- Ecosystem, Forests, North America, Plant Leaves, Trees, Water, Droughts, Tropical Climate
- Abstract
Extreme drought events have negative effects on forest diversity and functioning. At the species level, however, these effects are still unclear, as species vary in their response to drought through specific functional trait combinations. We used long-term demographic records of 21,821 trees and extensive databases of traits to understand the responses of 338 tropical dry forests tree species to ENSO
2015 , the driest event in decades in Northern South America. Functional differences between species were related to the hydraulic safety-efficiency trade-off, but unexpectedly, dominant species were characterised by high investment in leaf and wood tissues regardless of their leaf phenological habit. Despite broad functional trait combinations, tree mortality was more widespread in the functional space than tree growth, where less adapted species showed more negative net biomass balances. Our results suggest that if dry conditions increase in this ecosystem, ecological functionality and biomass gain would be reduced., (© 2020 The Authors. Ecology Letters published by John Wiley & Sons Ltd.) more...- Published
- 2021
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30. Biodiversity recovery of Neotropical secondary forests.
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Rozendaal DMA, Bongers F, Aide TM, Alvarez-Dávila E, Ascarrunz N, Balvanera P, Becknell JM, Bentos TV, Brancalion PHS, Cabral GAL, Calvo-Rodriguez S, Chave J, César RG, Chazdon RL, Condit R, Dallinga JS, de Almeida-Cortez JS, de Jong B, de Oliveira A, Denslow JS, Dent DH, DeWalt SJ, Dupuy JM, Durán SM, Dutrieux LP, Espírito-Santo MM, Fandino MC, Fernandes GW, Finegan B, García H, Gonzalez N, Moser VG, Hall JS, Hernández-Stefanoni JL, Hubbell S, Jakovac CC, Hernández AJ, Junqueira AB, Kennard D, Larpin D, Letcher SG, Licona JC, Lebrija-Trejos E, Marín-Spiotta E, Martínez-Ramos M, Massoca PES, Meave JA, Mesquita RCG, Mora F, Müller SC, Muñoz R, de Oliveira Neto SN, Norden N, Nunes YRF, Ochoa-Gaona S, Ortiz-Malavassi E, Ostertag R, Peña-Claros M, Pérez-García EA, Piotto D, Powers JS, Aguilar-Cano J, Rodriguez-Buritica S, Rodríguez-Velázquez J, Romero-Romero MA, Ruíz J, Sanchez-Azofeifa A, de Almeida AS, Silver WL, Schwartz NB, Thomas WW, Toledo M, Uriarte M, de Sá Sampaio EV, van Breugel M, van der Wal H, Martins SV, Veloso MDM, Vester HFM, Vicentini A, Vieira ICG, Villa P, Williamson GB, Zanini KJ, Zimmerman J, and Poorter L more...
- Subjects
- Conservation of Natural Resources, Geography, Biodiversity, Ecosystem, Forests, Tropical Climate
- Abstract
Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. more...
- Published
- 2019
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- View/download PDF
31. BioTIME: A database of biodiversity time series for the Anthropocene.
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Dornelas M, Antão LH, Moyes F, Bates AE, Magurran AE, Adam D, Akhmetzhanova AA, Appeltans W, Arcos JM, Arnold H, Ayyappan N, Badihi G, Baird AH, Barbosa M, Barreto TE, Bässler C, Bellgrove A, Belmaker J, Benedetti-Cecchi L, Bett BJ, Bjorkman AD, Błażewicz M, Blowes SA, Bloch CP, Bonebrake TC, Boyd S, Bradford M, Brooks AJ, Brown JH, Bruelheide H, Budy P, Carvalho F, Castañeda-Moya E, Chen CA, Chamblee JF, Chase TJ, Siegwart Collier L, Collinge SK, Condit R, Cooper EJ, Cornelissen JHC, Cotano U, Kyle Crow S, Damasceno G, Davies CH, Davis RA, Day FP, Degraer S, Doherty TS, Dunn TE, Durigan G, Duffy JE, Edelist D, Edgar GJ, Elahi R, Elmendorf SC, Enemar A, Ernest SKM, Escribano R, Estiarte M, Evans BS, Fan TY, Turini Farah F, Loureiro Fernandes L, Farneda FZ, Fidelis A, Fitt R, Fosaa AM, Daher Correa Franco GA, Frank GE, Fraser WR, García H, Cazzolla Gatti R, Givan O, Gorgone-Barbosa E, Gould WA, Gries C, Grossman GD, Gutierréz JR, Hale S, Harmon ME, Harte J, Haskins G, Henshaw DL, Hermanutz L, Hidalgo P, Higuchi P, Hoey A, Van Hoey G, Hofgaard A, Holeck K, Hollister RD, Holmes R, Hoogenboom M, Hsieh CH, Hubbell SP, Huettmann F, Huffard CL, Hurlbert AH, Macedo Ivanauskas N, Janík D, Jandt U, Jażdżewska A, Johannessen T, Johnstone J, Jones J, Jones FAM, Kang J, Kartawijaya T, Keeley EC, Kelt DA, Kinnear R, Klanderud K, Knutsen H, Koenig CC, Kortz AR, Král K, Kuhnz LA, Kuo CY, Kushner DJ, Laguionie-Marchais C, Lancaster LT, Min Lee C, Lefcheck JS, Lévesque E, Lightfoot D, Lloret F, Lloyd JD, López-Baucells A, Louzao M, Madin JS, Magnússon B, Malamud S, Matthews I, McFarland KP, McGill B, McKnight D, McLarney WO, Meador J, Meserve PL, Metcalfe DJ, Meyer CFJ, Michelsen A, Milchakova N, Moens T, Moland E, Moore J, Mathias Moreira C, Müller J, Murphy G, Myers-Smith IH, Myster RW, Naumov A, Neat F, Nelson JA, Paul Nelson M, Newton SF, Norden N, Oliver JC, Olsen EM, Onipchenko VG, Pabis K, Pabst RJ, Paquette A, Pardede S, Paterson DM, Pélissier R, Peñuelas J, Pérez-Matus A, Pizarro O, Pomati F, Post E, Prins HHT, Priscu JC, Provoost P, Prudic KL, Pulliainen E, Ramesh BR, Mendivil Ramos O, Rassweiler A, Rebelo JE, Reed DC, Reich PB, Remillard SM, Richardson AJ, Richardson JP, van Rijn I, Rocha R, Rivera-Monroy VH, Rixen C, Robinson KP, Ribeiro Rodrigues R, de Cerqueira Rossa-Feres D, Rudstam L, Ruhl H, Ruz CS, Sampaio EM, Rybicki N, Rypel A, Sal S, Salgado B, Santos FAM, Savassi-Coutinho AP, Scanga S, Schmidt J, Schooley R, Setiawan F, Shao KT, Shaver GR, Sherman S, Sherry TW, Siciński J, Sievers C, da Silva AC, Rodrigues da Silva F, Silveira FL, Slingsby J, Smart T, Snell SJ, Soudzilovskaia NA, Souza GBG, Maluf Souza F, Castro Souza V, Stallings CD, Stanforth R, Stanley EH, Mauro Sterza J, Stevens M, Stuart-Smith R, Rondon Suarez Y, Supp S, Yoshio Tamashiro J, Tarigan S, Thiede GP, Thorn S, Tolvanen A, Teresa Zugliani Toniato M, Totland Ø, Twilley RR, Vaitkus G, Valdivia N, Vallejo MI, Valone TJ, Van Colen C, Vanaverbeke J, Venturoli F, Verheye HM, Vianna M, Vieira RP, Vrška T, Quang Vu C, Van Vu L, Waide RB, Waldock C, Watts D, Webb S, Wesołowski T, White EP, Widdicombe CE, Wilgers D, Williams R, Williams SB, Williamson M, Willig MR, Willis TJ, Wipf S, Woods KD, Woehler EJ, Zawada K, Zettler ML, and Hickler T more...
- Abstract
Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene., Main Types of Variables Included: The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record., Spatial Location and Grain: BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km
2 (158 cm2 ) to 100 km2 (1,000,000,000,000 cm2 )., Time Period and Grain: BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year., Major Taxa and Level of Measurement: BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates., Software Format: .csv and .SQL. more...- Published
- 2018
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32. Opposing mechanisms affect taxonomic convergence between tree assemblages during tropical forest succession.
- Author
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Norden N, Boukili V, Chao A, Ma KH, Letcher SG, and Chazdon RL
- Subjects
- Costa Rica, Species Specificity, Ecosystem, Forests, Trees growth & development, Tropical Climate
- Abstract
Whether successional forests converge towards an equilibrium in species composition remains an elusive question, hampered by high idiosyncrasy in successional dynamics. Based on long-term tree monitoring in second-growth (SG) and old-growth (OG) forests in Costa Rica, we show that patterns of convergence between pairs of forest stands depend upon the relative abundance of species exhibiting distinct responses to the successional gradient. For instance, forest generalists contributed to convergence between SG and OG forests, whereas rare species and old-growth specialists were a source of divergence. Overall, opposing trends in taxonomic similarity among different subsets of species nullified each other, producing a net outcome of stasis over time. Our results offer an explanation for the limited convergence observed between pairwise communities and suggest that rare species and old-growth specialists may be prone to dispersal limitation, while the dynamics of generalists and second-growth specialists are more predictable, enhancing resilience in tropical secondary forests., (© 2017 John Wiley & Sons Ltd/CNRS.) more...
- Published
- 2017
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33. Multiple successional pathways in human-modified tropical landscapes: new insights from forest succession, forest fragmentation and landscape ecology research.
- Author
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Arroyo-Rodríguez V, Melo FP, Martínez-Ramos M, Bongers F, Chazdon RL, Meave JA, Norden N, Santos BA, Leal IR, and Tabarelli M
- Subjects
- Biodiversity, Conservation of Natural Resources, Humans, Research trends, Tropical Climate, Ecology trends, Ecosystem, Forests
- Abstract
Old-growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human-modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio-economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land-use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio-temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well-preserved biodiversity-rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i) succession must be examined using more comprehensive explanatory models, providing information about the forces affecting not only the presence but also the persistence of species and ecological groups, particularly of those taxa expected to be extirpated from HMTLs; (ii) SS research should integrate new aspects from forest fragmentation and landscape ecology research to address accurately the potential of secondary forests to serve as biodiversity repositories; and (iii) secondary forest stands, as a dynamic component of HMTLs, must be incorporated as key elements of conservation planning; i.e. secondary forest stands must be actively managed (e.g. using assisted forest restoration) according to conservation goals at broad spatial scales., (© 2015 Cambridge Philosophical Society.) more...
- Published
- 2017
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34. Successional dynamics in Neotropical forests are as uncertain as they are predictable.
- Author
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Norden N, Angarita HA, Bongers F, Martínez-Ramos M, Granzow-de la Cerda I, van Breugel M, Lebrija-Trejos E, Meave JA, Vandermeer J, Williamson GB, Finegan B, Mesquita R, and Chazdon RL
- Subjects
- Stochastic Processes, Ecosystem, Forests, Tropical Climate, Uncertainty
- 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. more...
- Published
- 2015
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35. Bio-resorbable plates as effective implant in paediatric mandibular fracture.
- Author
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Singh G, Mohammad S, Chak RK, Lepcha N, Singh N, and Malkunje LR
- Abstract
Aim: To evaluate the efficacy of bio-resorbable plates in paediatric mandibular fracture., Materials and Methods: In the present study, 40 cases of mandibular fractures were treated by Inion Cps plating system using, 2 and 2.5 mm (LPLA/DLPLA/TMC/PGA) bio-resorbable bone plates and screws of 6 and 8 mm screws. The assessment of the patients was done at 2 week, 1, 3, and 6 months using the clinical parameters and bite force recording., Results: There was significant reduction in pain at different follow-ups. Paraesthesia was found in two patients with body fracture which remained for 2 week and 1 month follow-up. No paraesthesia was found after 3rd follow-up. Significant stability of fracture fragments were found on different follow ups. Implant exposure was present only in two patients (5%) at 1 month follow up. There was significant increase in incisor, right molar and left molar bite force at 1, 3 and 6 months, from 2nd week onwards., Conclusion: These findings show that the use of bio-resorbable plates in paediatric mandibular fracture was efficacious enough to bear the masticatory loads during osteosynthesis of the fracture. The recent and significant achievement is the advent of bio-resorbable osteosynthesis devices that has almost solved the problems of stress shielding, secondary surgery and corrosion when metal implants are left-in situ. more...
- Published
- 2012
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- View/download PDF
36. Determinants of plant community assembly in a mosaic of landscape units in central Amazonia: ecological and phylogenetic perspectives.
- Author
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Umaña MN, Norden N, Cano A, and Stevenson PR
- Subjects
- Biodiversity, Climate, Colombia, Floods, Phylogeography, Trees, Phylogeny, Plant Physiological Phenomena, Plants classification
- Abstract
The Amazon harbours one of the richest ecosystems on Earth. Such diversity is likely to be promoted by plant specialization, associated with the occurrence of a mosaic of landscape units. Here, we integrate ecological and phylogenetic data at different spatial scales to assess the importance of habitat specialization in driving compositional and phylogenetic variation across the Amazonian forest. To do so, we evaluated patterns of floristic dissimilarity and phylogenetic turnover, habitat association and phylogenetic structure in three different landscape units occurring in terra firme (Hilly and Terrace) and flooded forests (Igapó). We established two 1-ha tree plots in each of these landscape units at the Caparú Biological Station, SW Colombia, and measured edaphic, topographic and light variables. At large spatial scales, terra firme forests exhibited higher levels of species diversity and phylodiversity than flooded forests. These two types of forests showed conspicuous differences in species and phylogenetic composition, suggesting that environmental sorting due to flood is important, and can go beyond the species level. At a local level, landscape units showed floristic divergence, driven both by geographical distance and by edaphic specialization. In terms of phylogenetic structure, Igapó forests showed phylogenetic clustering, whereas Hilly and Terrace forests showed phylogenetic evenness. Within plots, however, local communities did not show any particular trend. Overall, our findings suggest that flooded forests, characterized by stressful environments, impose limits to species occurrence, whereas terra firme forests, more environmentally heterogeneous, are likely to provide a wider range of ecological conditions and therefore to bear higher diversity. Thus, Amazonia should be considered as a mosaic of landscape units, where the strength of habitat association depends upon their environmental properties. more...
- Published
- 2012
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37. Phylogenetic density dependence and environmental filtering predict seedling mortality in a tropical forest.
- Author
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Paine CE, Norden N, Chave J, Forget PM, Fortunel C, Dexter KG, and Baraloto C
- Subjects
- Ecosystem, French Guiana, Models, Biological, Population Density, Seedlings anatomy & histology, Seedlings genetics, Trees genetics, Phylogeny, Seedlings physiology, Trees physiology, Tropical Climate
- Abstract
Negative density dependence (NDD) and environmental filtering (EF) shape community assembly, but their relative importance is poorly understood. Recent studies have shown that seedling's mortality risk is positively related to the phylogenetic relatedness of neighbours. However, natural enemies, whose depredations often cause NDD, respond to functional traits of hosts rather than phylogenetic relatedness per se. To understand the roles of NDD and EF in community assembly, we assessed the effects on seedling mortality of functional similarity, phylogenetic relatedness and stem density of neighbouring seedlings and adults in a species-rich tropical forest. Mortality risks increased for common species when their functional traits departed substantially from the neighbourhood mean, and for all species when surrounded by close relatives. This indicates that NDD affects community assembly more broadly than does EF, and leads to the tentative conclusion that natural enemies respond to phylogenetically correlated traits. Our results affirm the prominence of NDD in structuring species-rich communities., (© 2011 Blackwell Publishing Ltd/CNRS.) more...
- Published
- 2012
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38. A novel statistical method for classifying habitat generalists and specialists.
- Author
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Chazdon RL, Chao A, Colwell RK, Lin SY, Norden N, Letcher SG, Clark DB, Finegan B, and Arroyo JP
- Subjects
- Algorithms, Animals, Costa Rica, New South Wales, Population Density, Birds classification, Ecosystem, Models, Statistical, Trees classification
- Abstract
We develop a novel statistical approach for classifying generalists and specialists in two distinct habitats. Using a multinomial model based on estimated species relative abundance in two habitats, our method minimizes bias due to differences in sampling intensities between two habitat types as well as bias due to insufficient sampling within each habitat. The method permits a robust statistical classification of habitat specialists and generalists, without excluding rare species a priori. Based on a user-defined specialization threshold, the model classifies species into one of four groups: (1) generalist; (2) habitat A specialist; (3) habitat B specialist; and (4) too rare to classify with confidence. We illustrate our multinomial classification method using two contrasting data sets: (1) bird abundance in woodland and heath habitats in southeastern Australia and (2) tree abundance in second-growth (SG) and old-growth (OG) rain forests in the Caribbean lowlands of northeastern Costa Rica. We evaluate the multinomial model in detail for the tree data set. Our results for birds were highly concordant with a previous nonstatistical classification, but our method classified a higher fraction (57.7%) of bird species with statistical confidence. Based on a conservative specialization threshold and adjustment for multiple comparisons, 64.4% of tree species in the full sample were too rare to classify with confidence. Among the species classified, OG specialists constituted the largest class (40.6%), followed by generalist tree species (36.7%) and SG specialists (22.7%). The multinomial model was more sensitive than indicator value analysis or abundance-based phi coefficient indices in detecting habitat specialists and also detects generalists statistically. Classification of specialists and generalists based on rarefied subsamples was highly consistent with classification based on the full sample, even for sampling percentages as low as 20%. Major advantages of the new method are (1) its ability to distinguish habitat generalists (species with no significant habitat affinity) from species that are simply too rare to classify and (2) applicability to a single representative sample or a single pooled set of representative samples from each of two habitat types. The method as currently developed can be applied to no more than two habitats at a time. more...
- Published
- 2011
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39. Occurrence of Dirofilaria immitis and tick-borne infections caused by Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato and Ehrlichia canis in domestic dogs in France: results of a countrywide serologic survey.
- Author
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Pantchev N, Schaper R, Limousin S, Norden N, Weise M, and Lorentzen L
- Subjects
- Anaplasma phagocytophilum isolation & purification, Animals, Antibodies, Bacterial blood, Antigens, Helminth blood, Borrelia burgdorferi Group isolation & purification, Dirofilaria immitis isolation & purification, Dog Diseases microbiology, Dog Diseases parasitology, Dogs, Ehrlichia canis isolation & purification, Ehrlichiosis epidemiology, France epidemiology, Geography, Lyme Disease epidemiology, Seroepidemiologic Studies, Tick-Borne Diseases epidemiology, Dirofilariasis epidemiology, Dog Diseases epidemiology, Ehrlichiosis veterinary, Lyme Disease veterinary, Tick-Borne Diseases veterinary
- Abstract
The occurrence of Dirofilaria immitis antigen and antibodies against tick-borne pathogens in French dogs has been analysed based on 1,050 blood samples. Serum samples of 919 dogs (group A) were sent for a variety of diagnostic investigations, further 131 dogs (group B) were tested for a tentative diagnosis of heartworm disease. All samples were tested for D. immitis antigen. Samples in group A were also tested for specific antibodies against three tick-borne pathogens (Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato and Ehrlichia canis). Results were plotted in geographical maps. Occurrence of D. immitis antigen in group A (0.22%; 95 % CI: 0.03-0.78%) was significantly lower (p < 0.0001) than in group B (6.87%; 95% CI: 3.19-12.64%). Heartworm infections in both groups were regionally restricted to the areas of Bouches-du-Rhône in the South of France and Corsica. In group A, the calculated seroprevalence was 2.72% (95% CI: 1.77-3.99%) for A. phagocytophilum, 1.09% (95% CI: 0.52-1.99%) for B. burgdorferi and 0.33% (95% CI: 0.07-0.95%) for E. canis with a distribution of the positive cases throughout the country. This study represents the first data of A. phagocytophilum seroprevalence in the French dog population. more...
- Published
- 2009
- Full Text
- View/download PDF
40. Current surveys on the prevalence and distribution of Dirofilaria spp. in dogs in Germany.
- Author
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Pantchev N, Norden N, Lorentzen L, Rossi M, Rossi U, Brand B, and Dyachenko V
- Subjects
- Anaplasma phagocytophilum immunology, Animals, Antibodies, Bacterial blood, Blood parasitology, Borrelia immunology, Dog Diseases parasitology, Dogs, Germany epidemiology, Polymerase Chain Reaction methods, Prevalence, Reagent Kits, Diagnostic, Seroepidemiologic Studies, Dirofilaria classification, Dirofilaria isolation & purification, Dirofilariasis epidemiology, Dog Diseases epidemiology
- Abstract
The Central Upper-Rhine (Baden-Württemberg, Germany) is one of the warmest regions in Germany and also harbours abundant numbers of mosquitoes. Case reports on presumably autochthonous occurrence of Dirofilaria spp. were reported previously and were a reason for a further investigation into the occurrence of vector-borne pathogens. For this purpose, 44 hunting dogs from the Central Upper-Rhine region were tested between 4(th) and 29(th) June 2007. The blood samples were tested using the Knott's test and IDEXX SNAP 4Dx test. The Knott's test revealed unsheathed microfilaria identified as Dirofilaria repens by PCR in 3 dogs with no history of travelling (6.8%; 95% CI: 2.4-18.2%). The seroprevalence for Anaplasma phagocytophilum was 43.2% (95% CI: 29.7-57.8%), but only 4.5% (95% CI: 1.3-15.1%) for antibodies to Borrelia C6 peptide. Dirofilaria immitis antigen was not detected in any of the samples. A further 288 blood samples from non-hunting companion dogs of the Central Upper-Rhine region were tested negative for heartworm antigen between February and August 2007. more...
- Published
- 2009
- Full Text
- View/download PDF
41. Resilience of tropical rain forests: tree community reassembly in secondary forests.
- Author
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Norden N, Chazdon RL, Chao A, Jiang YH, and Vílchez-Alvarado B
- Subjects
- Costa Rica, Population Dynamics, Species Specificity, Tropical Climate, Ecosystem, Models, Biological, Trees growth & development
- Abstract
Understanding the recovery dynamics of ecosystems presents a major challenge in the human-impacted tropics. We tested whether secondary forests follow equilibrium or non-equilibrium dynamics by evaluating community reassembly over time, across different successional stages, and among multiple life stages. Based on long-term and static data from six 1-ha plots in NE Costa Rica, we show that secondary forests are undergoing reassembly of canopy tree and palm species composition through the successful recruitment of seedlings, saplings, and young trees of mature forest species. Such patterns were observed over time within sites and across successional stages. Floristic reassembly in secondary forests showed a clear convergence with mature forest community composition, supporting an equilibrium model. This resilience stems from three key factors co-occurring locally: high abundance of generalist species in the regional flora, high levels of seed dispersal, and local presence of old-growth forest remnants. more...
- Published
- 2009
- Full Text
- View/download PDF
42. Mast fruiting is a frequent strategy in woody species of eastern South America.
- Author
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Norden N, Chave J, Belbenoit P, Caubère A, Châtelet P, Forget PM, and Thébaud C
- Subjects
- Biodiversity, Conservation of Natural Resources, Ecology, Ecosystem, Models, Statistical, Models, Theoretical, Plant Physiological Phenomena, Seedlings, South America, Time Factors, Tropical Climate, Fruit, Seeds, Trees
- Abstract
Background: It is thought that mast seeding is a rare reproductive strategy in the tropics, since tropical climates are less variable, and fruit consumers tend to be more generalist in these regions. However, previous tests of this hypothesis were based on only few tropical datasets, and none from tropical South America. Moreover, reproductive strategies have been quantified based on the coefficient of variation of interannual seed production, an index that potentially confounds masting and high interannual variability in seed production., Methodology/principal Findings: We developed a new approach to model the monthly variability in seed production for 28 tree species, and 20 liana species monitored during 5 years in a tropical forest of Central French Guiana. We found that 23% of the species showed a masting pattern, 54% an annual fruiting pattern, and 23% an irregular fruiting pattern. The majority of masting species were trees (8 out of 11), most of them animal-dispersed. The classification into reproductive strategies based on the coefficient of variation was inconsistent with our results in nearly half of the cases., Conclusions/significance: Our study is the first to clearly evidence the frequency of the masting strategy in a tropical forest community of Eastern South America. The commonness of the masting strategy in tropical plants may promote species coexistence through storage dynamics. more...
- Published
- 2007
- Full Text
- View/download PDF
43. Diagnosis of mannosidosis.
- Author
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Ockerman PA, Autio S, and Norden NE
- Subjects
- Child, Female, Humans, Male, Carbohydrate Metabolism, Inborn Errors diagnosis, Mannose metabolism
- Published
- 1973
- Full Text
- View/download PDF
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