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Campillo, F., & Rossi, V. (2009). Convolution Particle Filter for Parameter Estimation in General State-Space Models. IEEE Trans. Aerosp. Electron. Syst., 45(3), 1063–1072.
Abstract: The state-space modeling of partially observed dynamical systems generally requires estimates of unknown parameters. The dynamic state vector together with the static parameter vector can be considered as an augmented state vector. Classical filtering methods, such as the extended Kalman filter (EKF) and the bootstrap particle filter (PF), fail to estimate the augmented state vector. For these classical filters to handle the augmented state vector, a dynamic noise term should be artificially added to the parameter components or to the deterministic component of the dynamical system. However, this approach degrades the estimation performance of the filters. We propose a variant of the PF based on convolution kernel approximation techniques. This approach is tested on a simulated case study.
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Baraloto, C., Ferreira, E., Rockwell, C., & Walthier, F. (2007). Limitations and Applications of Parataxonomy for Community Forest Management in Southwestern Amazonia. Ethnobotany Research & Applications, 5, 77–84.
Abstract: We examined the limitations of parataxonomic inventories for developing management plans for woody plant resources in tropical rain forests of southwestern Amazonia. Using compilations of herbarium labels, forest personnel interviews and published species descriptions, we assessed the accuracy of common names as parataxonomic units (PUs). We identified 384 common names for 310 harvested woody plant species in the Brazilian state of Acre, of which only 50% were unique to a single taxonomic species. About 10% of common names referred to more than one species, more than half of which included multiple genera. For the 106 species from the Acre sample common to the MAP region including Madre de Dios, Peru and Pando, Bolivia, we identified 198 common names. Splitting was much more frequent in this sample, with more than 80% of species having more than one common name. When the Acre sample was expanded to 131 species from the Brazilian Amazon region, including the states of Amazonas and Para, we identified 740 common names, with nearly 90% of species being represented by more than one common name. Errors and inaccuracy of parataxonomy may contribute to market instability if product orders can not be homogenized within regional markets, and to unsustainable harvests if species are mistakenly lumped into single parataxonomic units. We discuss several programs currently being implemented by our collaborative team in the region to address this issue, including field guides based on digital photography, field courses, and workshops featuring discussions between regional inventory personnel and botanists.
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Vedel, V., Apostolou, Z., Arthur, W., Akam, M., & Brena, C. (2010). An early temperature-sensitive period for the plasticity of segment number in the centipede Strigamia maritima. Evol Dev, 12(4), 347–352.
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Petillon, J., Lambeets, K., Montaigne, W., Maelfait, J. P., & Bonte, D. (2010). Habitat structure modified by an invasive grass enhances inundation withstanding in a salt-marsh wolf spider. Biological Invasions, 12(9), 3219–3226.
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Petillon, J., Montaigne, W., & Renault, D. (2009). Hypoxic coma as a strategy to survive inundation in a salt-marsh inhabiting spider. Biol. Lett., 5(4), 442–445.
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Sist, P., & Brown, N. (2004). Silvicultural intensification for tropical forest conservation: a response to Fredericksen and Putz. Biodiversity and Conservation, 13(12), 2381–2385.
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Sist, P., Fimbel, R., Sheil, D., Nasi, R., & Chevallier, M. H. (2003). Towards sustainable management of mixed dipterocarp forests of South-east Asia: moving beyond minimum diameter cutting limits. Environmental Conservation, 30(4), 364–374.
Abstract: 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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Sist, P., Picard, N., & Gourlet-Fleury, S. (2003). Sustainable cutting cycle and yields in a lowland mixed dipterocarp forest of Borneo. Ann. For. Sci., 60(8), 803–814.
Abstract: 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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Sist, P., Sheil, D., Kartawinata, K., & Priyadi, H. (2003). Reduced-impact logging in Indonesian Borneo: some results confirming the need for new silvicultural prescriptions. For. Ecol. Manage., 179(1-3), 415–427.
Abstract: 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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Sist, P., & Nguyen-The, N. (2002). Logging damage and the subsequent dynamics of a dipterocarp forest in East Kalimantan (1990-1996). For. Ecol. Manage., 165(1-3), 85–103.
Abstract: 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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