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Sist, P.; Fimbel, R.; Sheil, D.; Nasi, R.; Chevallier, M.H. |
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Title |
Towards sustainable management of mixed dipterocarp forests of South-east Asia: moving beyond minimum diameter cutting limits |
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Journal Article |
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Year |
2003 |
Publication |
Environmental Conservation |
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30 |
Issue |
4 |
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364-374 |
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Selective logging applied in tropical forests is based on one universal criterion: a minimum diameter cutting limit for all commercial timber species. Minimum diameter cutting limits in mixed dipterocarp forests of the Malesia region lead to high felling intensities (10-20+ trees ha(-1)). Such extraction rates create massive stand damage (> 50% of the remaining tree population), which has a negative impact on the regeneration and growth of many harvested dipterocarp, species. As such, the minimum diameter cutting limit approach is seldom compatible with sustainable forest management. Where basic ecological characteristics of the commercial species are considered in timber harvesting prescriptions, mixed dipterocarp, forests appear capable of sustained timber yields, habitat conservation, and providing other goods and services. This paper first presents the main silvicultural systems developed in mixed dipterocarp, forests of Western Malesia and then reviews current knowledge of dipterocarp, biology to finally develop guidelines aimed at improving the ecological sustainability of production forests of Western Malesia. These guidelines, a pragmatic reflection of science and 'best guess' judgement, include: (1) integration of reduced-impact logging practices into normal management operations; (2) cutting of eight trees ha(-1) or less (with a felling cycle of 40-60 years to be determined according to local conditions); (3) defining minimum diameter cutting limits according to the structure, density and diameter at reproduction of target species; (4) avoiding harvesting species with less than one adult tree ha(-1) (diameter at breast height [dbh] greater than or equal to 50 cm over an area of 50-100 ha); (5) minimizing the size and connectivity of gaps (< 600 m(2) whenever possible); (6) refraining from treatments such as understorey clearing; and (7) providing explicit protection for key forest species and the ecological processes they perform. Further refinement is encouraged to allow for local conditions, and for other forest types. |
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0376-8929 |
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WOS:000188812100007 |
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EcoFoG @ webmaster @ |
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309 |
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Sist, P.; Picard, N.; Gourlet-Fleury, S. |
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Title |
Sustainable cutting cycle and yields in a lowland mixed dipterocarp forest of Borneo |
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Journal Article |
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Year |
2003 |
Publication |
Annals of Forest Science |
Abbreviated Journal |
Ann. For. Sci. |
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60 |
Issue |
8 |
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803-814 |
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Based on a 6 year monitoring of the dynamics of a mixed dipterocarp forest in East Borneo (1990-1996), we built a matrix model to predict the sustainable cutting cycle in relation with the extraction and damage rates. Plots were ordered according to three main groups of damage and logging intensity. The first group G1 gathered slightly damaged plots with a remaining basal area greater than or equal to80% of the original (mean logging intensity = 6 trees ha(-1)). Plots belonging to G2, had a remaining basal area varying between 70 and 79% of the original one (mean logging intensity = 8 trees ha(-1)). Finally, G3 gathers highly damaged plots with a remaining basal area < 70% of the original one and a high logging intensity (mean = 14 trees ha(-1)). The mean sustainable cutting cycles predicted in the three groups were significantly different and equal 27, 41 and 89 years in G1, G2 and G3 respectively. However, the respective mean annual extracted volumes were similar: 1.6, 1.8 and 1.4 m(3) ha(-1) year(-1), respectively in G1, G2 and G3. The model suggests that a 40 year cycle, extracting 8 trees ha(-1) (60 m(3) ha(-1)) and an annual volume of 1.5 m(3) ha(-1) year(-1) is the best option to preserve ecological integrity of the forest, to ensure yield sustainability and, according to existing cost analysis, economic profitability. This result is also consistent with other studies which already demonstrated that logging damage reduction using RIL techniques could be only significant with a moderate felling intensity not exceeding 8 trees ha(-1). This felling intensity threshold can be easily achieved by applying simple harvesting rules. |
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1286-4560 |
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WOS:000221039000007 |
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EcoFoG @ webmaster @ |
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310 |
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Sist, P.; Sheil, D.; Kartawinata, K.; Priyadi, H. |
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Title |
Reduced-impact logging in Indonesian Borneo: some results confirming the need for new silvicultural prescriptions |
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Journal Article |
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Year |
2003 |
Publication |
Forest Ecology and Management |
Abbreviated Journal |
For. Ecol. Manage. |
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179 |
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1-3 |
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415-427 |
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Reduced-impact logging (RIL) and conventional techniques (CNV) were compared in a mixed dipterocarp hill forest in East Kalimantan in three blocks of about 100 ha each. Damage was evaluated using pre- and post-harvesting assessments in 24 one-hectare sample plots. RIL techniques nearly halved the number of trees destroyed (36 vs 60 trees/ha). RIL's main benefit was in the reduction of skidding damage (9.5% of the original tree population in RIL vs 25% in CNV). Before logging, mean canopy openness in CNV (three plots only) and RIL (9 plots) was similar (3.6 and 3.1%) and not significantly different (x(2) = 2.73, P = 0.254). After logging, the mean canopy openness was 19.2% in CNV (n = 9 plots) and 13.3% in RIL (n = 8 plots), and the distributions of the canopy class in RIL and CNV significantly different x(2) = 43.56, P < 0.001). CNV plots showed a higher proportion of measurements in the most open class greater than or equal to30% than in RIL. At a larger scale, the area of skidtrail per unit timber volume extracted was halved in the RIL compartment (15 m(2) vs 27 m(2) m(-3) for CNV). However, under high felling intensity (>8 trees/ha), both stand damage and canopy disturbance in RIL approached those recorded in CNV under low or moderate felling regime. Over this felling intensity threshold the effectiveness of RIL in reducing tree damage is limited. In mixed dipterocarp forest where harvestable timber density generally exceeds 10 trees/ha, a minimum diameter felling limit is clearly insufficient to keep extraction rates below 8 trees/ha. Based on these new results and previous studies in Borneo, we suggest three silvicultural rules: (1) to keep a minimum distance between stumps of ca. 40 m, (2) to ensure only single tree gaps using directional felling, (3) to harvest only stems with 60-100 cm dbh. Foresters, policy makers and certifiers should consider these as criteria for sustainable forest management. We emphasise the need to expand harvesting studies to look at impacts and trade-offs across larger forest landscapes, to expand RIL beyond silvicultural concepts and to include the maintenance of other forest goods and services. (C) 2002 Elsevier Science B.V. All rights reserved. |
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0378-1127 |
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WOS:000183836300033 |
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EcoFoG @ webmaster @ |
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311 |
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Sist, P.; Nguyen-The, N. |
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Logging damage and the subsequent dynamics of a dipterocarp forest in East Kalimantan (1990-1996) |
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Journal Article |
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Year |
2002 |
Publication |
Forest Ecology and Management |
Abbreviated Journal |
For. Ecol. Manage. |
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165 |
Issue |
1-3 |
Pages |
85-103 |
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The effects of logging damage on forest dynamics processes were assessed in a lowland dipterocarp forest of East Kalimantan, Indonesia. From 1990 to 1991, twelve 4 ha plots (200 m x 200 m) each divided into four I ha subplots were set up and all trees with dbh greater than or equal to 10 cm measured and identified at least at the generic level. Logging was carried out from November 1991 to March 1992 in nine plots while three plots served as control. The 48 subplots were grouped according to the proportion Of remaining basal area after harvesting, as follows: group I with more than 80% of the original basal area remaining, group 2 with 70-79%, group 3 with less than 70%, and group 4 as control plots. Remeasurements were carried out just after logging in 1992 and then every 2 years until 1996. Felling intensity varied from I to 17 stems ha(-1) (50-250 m(3) ha(-1)). In primary forest, mean annual mortality remained constant to 1.5% per year throughout the study period while mean annual mortality rate was significantly higher in logged-over forest (2.6% per year). This higher rate resulted from a higher mortality of injured trees (4.9% per year). Four years after logging, mortality rates in logged-over and primary forest were similar. Recruitment remained constant at 8 trees ha(-1) per year in primary forest and varied from 14 to 32 trees ha(-1) per year in logged-over stand in proportion with the amount of damage. In stands with the lowest remaining basal area, the establishment and growth of dipterocarps was strongly limited by the strong regeneration of pioneer species. This study suggests that total basal area removed by logging in primary forest (harvested trees and trees killed during felling and skidding) should not exceed 15% of the original one; reduced-impact logging (RIL) techniques applied with a maximum harvesting intensity of 8 trees ha(-1), can keep logging damage under this threshold. (C) 2002 Elsevier Science B.V. All rights reserved. |
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0378-1127 |
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WOS:000176620100008 |
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EcoFoG @ webmaster @ |
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312 |
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Paine, C.E.T.; Baraloto, C.; Chave, J.; Herault, B. |
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Title |
Functional traits of individual trees reveal ecological constraints on community assembly in tropical rain forests |
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Journal Article |
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2011 |
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Oikos |
Abbreviated Journal |
Oikos |
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120 |
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5 |
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720-727 |
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Niche differentiation and ecological filtering are primary ecological processes that shape community assembly, but their relative importance remains poorly understood. Analyses of the distributions of functional traits can provide insight into the community structure generated by these processes. We predicted the trait distributions expected under the ecological processes of niche differentiation and environmental filtering, then tested these predictions with a dataset of 4672 trees located in nine 1-ha plots of tropical rain forest in French Guiana. Five traits related to leaf function (foliar N concentration, chlorophyll content, toughness, tissue density and specific leaf area), and three traits related to stem function (trunk sapwood density, branch sapwood density, and trunk bark thickness), as well as laminar surface area, were measured on every individual tree. There was far more evidence for environmental filtering than for niche differentiation in these forests. Furthermore, we contrasted results from species-mean and individual-level trait values. Analyses that took within-species trait variation into account were far more sensitive indicators of niche differentiation and ecological filtering. Species-mean analyses, by contrast, may underestimate the effects of ecological processes on community assembly. Environmental filtering appeared somewhat more intense on leaf traits than on stem traits, whereas niche differentiation affected neither strongly. By accounting for within-species trait variation, we were able to more properly consider the ecological interactions among individual trees and between individual trees and their environment. In so doing, our results suggest that the ecological processes of niche differentiation and environmental filtering may be more pervasive than previously believed. |
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[Paine, C. E. Timothy] ENGREF, UMR Ecol Forets Guyane, Kourou 97387, French Guiana, Email: timothy.paine@ieu.uzh.ch |
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Wiley-Blackwell |
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0030-1299 |
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ISI:000289740200008 |
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EcoFoG @ webmaster @ |
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313 |
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Dejean, A. |
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Title |
Prey Capture Behavior in an Arboreal African Ponerine Ant |
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Journal Article |
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2011 |
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PLoS One |
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PLoS One |
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6 |
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5 |
Pages |
e19837 |
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I studied the predatory behavior of Platythyrea conradti, an arboreal ponerine ant, whereas most species in this subfamily are ground-dwelling. The workers, which hunt solitarily only around dusk, are able to capture a wide range of prey, including termites and agile, nocturnal insects as well as diurnal insects that are inactive at that moment of the Nyctemeron, resting on tree branches or under leaves. Prey are captured very rapidly, and the antennal palpation used by ground-dwelling ponerine species is reduced to a simple contact; stinging occurs immediately thereafter. The venom has an instant, violent effect as even large prey (up to 30 times the weight of a worker) never struggled after being stung. Only small prey are not stung. Workers retrieve their prey, even large items, singly. To capture termite workers and soldiers defending their nest entrances, ant workers crouch and fold their antennae backward. In their role as guards, the termites face the crouching ants and end up by rolling onto their backs, their legs batting the air. This is likely due to volatile secretions produced by the ants' mandibular gland. The same behavior is used against competing ants, including territorially-dominant arboreal species that retreat further and further away, so that the P. conradti finally drive them from large, sugary food sources. |
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[Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: alain.dejean@wanadoo.fr |
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Public Library Science |
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1932-6203 |
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ISI:000290483600033 |
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EcoFoG @ webmaster @ |
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316 |
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Brouard, O.; Le Jeune, A.H.; Leroy, C.; Cereghino, R.; Roux, O.; Pelozuelo, L.; Dejean, A.; Corbara, B.; Carrias, J.F. |
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Are Algae Relevant to the Detritus-Based Food Web in Tank-Bromeliads? |
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Journal Article |
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2011 |
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PLoS One |
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PLoS One |
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6 |
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5 |
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e20129 |
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We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from similar to 10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web. |
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[Brouard, Olivier; Le Jeune, Anne-Helene; Corbara, Bruno; Carrias, Jean-Francois] Univ Clermont Ferrand, CNRS, Lab Microorganismes Genome & Environm, LMGE,UMR 6023, Aubiere, France, Email: j-francois.carrias@univ-bpclermont.fr |
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Public Library Science |
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1932-6203 |
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ISI:000290720200066 |
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EcoFoG @ webmaster @ |
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319 |
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Verbeeck, H.; Peylin, P.; Bacour, C.; Bonal, D.; Steppe, K.; Ciais, P. |
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Seasonal patterns of CO2 fluxes in Amazon forests: Fusion of eddy covariance data and the ORCHIDEE model |
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2011 |
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Journal Of Geophysical Research-Biogeosciences |
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J. Geophys. Res.-Biogeosci. |
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116 |
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2 |
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G02018 |
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[1] In some regions of the Amazon, global biogeophysical models have difficulties in reproducing measured seasonal patterns of net ecosystem exchange (NEE) of carbon dioxide. The global process-based biosphere model Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) used in this study showed that a standard model parameterization produces seasonal NEE patterns that are opposite in phase to the eddy flux data of the tropical evergreen forest at the Tapajos km 67 site (Brazil), like many other global models. However, we optimized several key parameters of ORCHIDEE using eddy covariance data of the Tapajos km 67 site in order to identify the driving factors of the seasonal variations in CO2 flux in this tropical forest ecosystem. The validity of the retrieved parameter values was evaluated for two other flux tower sites in the Amazon. The different tested optimization scenarios showed that only a few parameters substantially improve the fit to NEE and latent heat data. Our results confirm that these forests have the ability to maintain high transpiration and photosynthesis during the dry season in association with a large soil depth (D-soil = 10 m) and a rooting system density that decreases almost linearly with depth (H-root = 0.1). Previous analyses of seasonal variations in eddy covariance fluxes indicated that higher GPP levels were reached in the dry season compared to the wet season. Our optimization analysis suggests that this pattern could be caused by a leaf flush at the start of the dry season increasing the photosynthetic capacity of the canopy. Nevertheless, the current model structure is not yet able to simulate such a leaf flush, and we therefore suggest improving the ORCHIDEE model by including a specific phenology module that is driven by light availability for the tropical evergreen plant functional types. In addition, our results highlight both the potential and the limitations of flux data to improve global terrestrial models. Several parameters were not identifiable, and the risk of overfitting of the model was illustrated. Nevertheless, we conclude that these models can be improved substantially by assimilating site level flux data over the tropics. |
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[Verbeeck, Hans; Steppe, Kathy] Univ Ghent, Plant Ecol Lab, Dept Appl Ecol & Environm Biol, Fac Biosci Engn, B-9000 Ghent, Belgium, Email: hans.verbeeck@ugent.be |
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Amer Geophysical Union |
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0148-0227 |
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ISI:000290933500002 |
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EcoFoG @ webmaster @ |
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321 |
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Roux, O.; Cereghino, R.; Solano, P.J.; Dejean, A. |
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Title |
Caterpillars and Fungal Pathogens: Two Co-Occurring Parasites of an Ant-Plant Mutualism |
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Journal Article |
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2011 |
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PLoS One |
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PLoS One |
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6 |
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5 |
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e20538 |
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In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth. |
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[Roux, Olivier; Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: olivier.roux@ird.fr |
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Public Library Science |
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1932-6203 |
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ISI:000291097600091 |
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EcoFoG @ webmaster @ |
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322 |
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Author |
Bremaud, I.; Amusant, N.; Minato, K.; Gril, J.; Thibaut, B. |
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Title |
Effect of extractives on vibrational properties of African Padauk (Pterocarpus soyauxii Taub.) |
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Journal Article |
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Year |
2011 |
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Wood Science and Technology |
Abbreviated Journal |
Wood Sci. Technol. |
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45 |
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3 |
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461-472 |
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Abstract |
Extractives can affect the vibrational properties tan delta (damping coefficient) and E'/rho (specific Young's modulus), but this is highly dependent on species, compounds, and cellular locations. This paper investigates such effects for African Padauk (Pterocarpus soyauxii Taub.), a tropical hardwood with high extractives content and a preferred material for xylophones. Five groups of 26 heartwood specimens with large, yet comparable, ranges in vibrational properties were extracted in different solvents. Changes in vibrational properties were set against yields of extracts and evaluation of their cellular location. Methanol (ME) reached most of the compounds (13%), located about half in lumen and half in cell-wall. Water solubility was extremely low. tan delta and E'/rho were very strongly related (R (2) a parts per thousand yen 0.93), but native wood had abnormally low values of tan delta, while extraction shifted this relation towards higher tan delta values. ME extracted heartwood became in agreement with the average of many species, and close to sapwood. Extractions increased tan delta as much as 60%, irrespective of minute moisture changes or initial properties. Apparent E'/rho was barely changed (+2% to -4%) but, after correcting the mass contribution of extracts, it was in fact slightly reduced (down to -10% for high E'/rho), and increasingly so for specimens with low initial values of E'/rho. |
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Address |
[Bremaud, I; Minato, K] Kyoto Prefectural Univ, Lab Forest Resource Circulating Circles, Grad Sch Life & Environm Sci, Kyoto 6068522, Japan, Email: iris_bremaud@hotmail.com |
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Springer |
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ISSN |
0043-7719 |
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WOS:000292550700005 |
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EcoFoG @ webmaster @ |
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329 |
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