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See detailThe seed dispersal of the afro- tropical tree species Staudtia kamerunensis (Myristicaceae)
Hambuckers, Alain ULg

Scientific conference (2014, December 27)

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See detailImportance des modèles de distribution de niche potentielle dans la gestion des espèces tropicales exploitées: cas des taxons du genre Guibourtia Benn
Tosso, Dji-ndé Félicien ULg; Daïnou, Kasso ULg; Hambuckers, Alain ULg et al

Poster (2014, September 24)

De la famille des (Fabaceae / Caesalpinioideae) et composé de 13 espèces en Afrique, le genre Guibourtia comporte des taxons à forte valeur culturelle et à forte valeur commerciale. Aujourd'hui, la ... [more ▼]

De la famille des (Fabaceae / Caesalpinioideae) et composé de 13 espèces en Afrique, le genre Guibourtia comporte des taxons à forte valeur culturelle et à forte valeur commerciale. Aujourd'hui, la pression de l'exploitation combinée aux faibles densités de ce genre, fait a priori peser d’importantes menaces sur certaines de ses populations. Un projet de recherche a donc été initié afin de mieux comprendre la structure et la diversité génétique des populations de Guibourtia, en lien avec l'exploitation forestière et les patrons de reproduction spécifiques. Un premier volet de la recherche a consisté à identifier les déterminants climatiques expliquant la distribution des espèces. Nous avons combinée des modèles statiques (Maxent et régression logistique) avec des données du modèle climatique global CNRM CM5, et sur la base de l'occurrence de ces taxons entre 1950 et 2000. Il en ressort que les espèces du genre Guibourtia sont sensibles aux facteurs précipitation (69,2 %) et amplitude thermique (74,3 %). Dans un second temps, il sera utilisé les modèles climatiques des ères géologiques passées afin d'inférer la distribution de l'espèce au cours du Quaternaire, et de faire le lien avec des analyses phylogénétiques et phylogéographiques. Il sera également possible d'évaluer la distribution future de l'espèce tenant compte des modèles d'évolution du climat. Enfin, le projet de recherche s'attèlera particulièrement aux relations phylogénétiques entre espèces morphologiquement similaires en sympatrie ou parapatrie, en caractérisant en détail les flux de gènes entre individus de ces taxons proches, ainsi que leur degré de similarité physiologique. Les résultats de l’étude in fine contribueront à proposer des stratégies de conservation et de gestion durable dans le contexte de l’exploitation forestière d’Afrique centrale et du changement climatique en cours. [less ▲]

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See detailModelling the distribution of key tree species used by lion tamarins in the Brazilian Atlantic forest under a scenario of future climate change
Raghunathan, Poornima ULg; Hambuckers, Alain ULg; François, Louis ULg et al

in Regional Environmental Change (2014)

We used three IPCC climate change scenarios (A1B, A2 and B1) in a dynamic vegetation model (CARAIB), to determine the potential future distribution of 75 tree species used by two endemic primate species ... [more ▼]

We used three IPCC climate change scenarios (A1B, A2 and B1) in a dynamic vegetation model (CARAIB), to determine the potential future distribution of 75 tree species used by two endemic primate species from the Brazilian Atlantic Forest (BAF). Habitat conservation is a vital part of strategies to protect endangered species, and this is a new approach to understanding how key plant species needed for survival of golden lion tamarins (Leontopithecus rosalia) and golden-headed lion tamarins (L. chrysomelas) might be affected by climate change and what changes to their distribution are likely. The model accurately predicted the current distribution of BAF vegetation types, for 66 % of the individual tree species with 70 % agreement obtained for presence. In the simulation experiments for the future, 72 out of 75 tree species maintained more than 95 % of their original distribution and all species showed a range expansion. At the biome level, we note a substantial decrease in the sub-tropical forest area. There is some fragmentation of the savannah, which is encroached mostly by tropical seasonal forest. Where the current distribution shows a large sub-tropical forest biome, it has been replaced or encroached by tropical rainforest. The results suggested that the trees may benefit from an increase in temperature, if and only if soil water availability is not altered significantly, as was the case with climate simulations that were used. However, these results must be coupled with other information to maximise usefulness to conservation since BAF is already highly fragmented and subject to high anthropic pressure. [less ▲]

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See detailModelling seed dispersal and tropical forest regeneration :application to Staudtia kamerunensis in the WWF Lake Tele-Tumba Landscape in DR Congo
Coos, William ULg; Dury, Marie ULg; Trolliet, Franck ULg et al

Poster (2014, June)

Unsustainable hunting and slash-and-burn farming in tropical forests can lead to the empty forest syndrome. It is characterized by the loss of key species essential in the maintenance and regeneration of ... [more ▼]

Unsustainable hunting and slash-and-burn farming in tropical forests can lead to the empty forest syndrome. It is characterized by the loss of key species essential in the maintenance and regeneration of the forest. Indeed the main mechanism of this regeneration is seed dispersal, which for tropical trees is usually driven by animals, and the alteration of this process through a reduction of the disperser population may have serious consequences on forest composition. Computer models are powerful tools to study these processes, not only towards a better understanding of the key mechanisms controlling tropical forest regeneration, but also with the aim of optimising forest management and exploitation to reach a better equilibrium between tropical tree species and their seed dispersers. This study describes a seed dispersal module ultimately developed to analyze the regeneration of the rainforest in the WWF Lake Tele – Lake Tumba Landscape in RD Congo (BIOSERF project funded by Belgian Science Policy). The module has been developed to upgrade the CARAIB dynamic vegetation model, which is used in the BIOSERF project. Data are derived from a field study in which we analyzed seed dispersal of a common tree species (Staudtia kamerunensis) and we determined the community of its main dispersers (largely dominated by the hornbill Bycanistes albotibialis). Additional data (density of S. kamerunensis, habitat use and retention time in the digestive tract of hornbills to simulate dispersal kernel) were obtained from literature and satellite images. Different simulations were performed to represent seed rain over time and a survival rate was applied to show the regeneration. The module was able to provide a percentage of recolonization of degraded places. In the end, this result was compared to field studies, which provide close percentage of recolonization [less ▲]

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See detailModelling the future range and productivity of African tree species. Perspectives and limits
Hambuckers, Alain ULg; Dury, Marie ULg; Tosso, Dji-ndé Félicien ULg et al

Poster (2014, June)

There remains a lack of information on the future of plant species in many parts of Africa under the threads of climate change with the exception of the mountainous areas. Models are valuables tools to ... [more ▼]

There remains a lack of information on the future of plant species in many parts of Africa under the threads of climate change with the exception of the mountainous areas. Models are valuables tools to examine this problem because they permit to extrapolate basic information as simple as species occurrence coming from a restricted number of localities to the entire continent. Niche-based models, like logistic regression or MaxEnt, easily allow fitting empirical relationships between environmental variables related to climate and possibly to soil properties. They produce probabilities of occurrence for the present with good accuracy (calibration phase). Projections for the future are made by switching the explanatory data set with future conditions. These models however are limited by the fact that it is difficult to integrate physiological response to increasing CO2 air concentration. Dynamic vegetation models (DVMs) are process-based models that simulate plant environment (soil water, light intensity at various heights, etc.) and plant physiology (transpiration, CO2 fixation, photosynthesis, respiration, carbon allocation, etc.) from climate variables, soil properties, and elevation. They could be run at various scales, from global to regional or even local scale, and simulate the growth of plant functional types (PFTs), of biological affinity groups (BAGs) or of species. A model like CARAIB is able to simulate PFTs and BAGs growth (occurrence and productivity) with rather good accuracy for Western Europe. For the future, the simulations confirm that the physiological effect of CO2 concentration change is dramatic but not easily foreseeable because it depends on overall fertility of the sites (Dury et al., iForest – Biogeosciences and Forestry, 4:82-99, 2011). From this conclusion, spatial and temporal variations of fertility would have to be introduced in modelling studies to reach more operational conclusions. Questions arising about the future of ecosystem services in tropical countries highlight particular plant species (BIOSERF project funded by the Belgian Science Policy: Sustainability of tropical forest biodiversity and services under climate and human pressure). In this study, we model a set of 11 selected African tree species including several Congolese species with logistic regression, MaxEnt and CARAIB models. The two niche-based-models rather properly simulate the ranges obtained with the alpha-hull polygon method. CARAIB correctly simulates the range of the evergreen species but not of the deciduous trees. We examine how physiological knowledge could be use to improve the model. IN particular, we conclude that bud dormancy breaking representation has to be upgraded in the model because this process is likely to control the range of the species. It should act in combination with the specific bioclimatic constants controlling the hydrological and thermal stress and the germination. Additionally, we examine the evolution of the ranges at the 2050 horizon using one of the most recent socio-economic scenarios. [less ▲]

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See detailNest grouping patterns of bonobos (Pan paniscus) in relation to fruit availability in a forest-savannah mosaic
Serckx, Adeline ULg; Huynen, Marie-Claude ULg; Bastin, Jean-François ULg et al

in PLoS ONE (2014)

A topic of major interest in socio-ecology is the comparison of chimpanzees and bonobos’ grouping patterns. Numerous studies have highlighted the impact of social and environmental factors on the ... [more ▼]

A topic of major interest in socio-ecology is the comparison of chimpanzees and bonobos’ grouping patterns. Numerous studies have highlighted the impact of social and environmental factors on the different evolution in group cohesion seen in these sister species. We are still lacking, however, key information about bonobo social traits across their habitat range, in order to make accurate inter-species comparisons. In this study we investigated bonobo social cohesiveness at nesting sites depending on fruit availability in the forest-savannah mosaic of western Democratic Republic of Congo (DRC), a bonobo habitat which has received little attention from researchers and is characterized by high food resource variation within years. We collected data on two bonobo communities. Nest counts at nesting sites were used as a proxy for night grouping patterns and were analysed with regard to fruit availability. We also modelled bonobo population density at the site in order to investigate yearly variation. We found that one community density varied across the three years of surveys, suggesting that this bonobo community has significant variability in use of its home range. This finding highlights the importance of forest connectivity, a likely prerequisite for the ability of bonobos to adapt their ranging patterns to fruit availability changes. We found no influence of overall fruit availability on bonobo cohesiveness. Only fruit availability at the nesting sites showed a positive influence, indicating that bonobos favour food ‘hot spots’ as sleeping sites. Our findings have confirmed the results obtained from previous studies carried out in the dense tropical forests of DRC. Nevertheless, in order to clarify the impact of environmental variability on bonobo social cohesiveness, we will need to make direct observations of the apes in the forest-savannah mosaic as well as make comparisons across the entirety of the bonobos’ range using systematic methodology. [less ▲]

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See detailModelling the Congo basin ecosystems with a dynamic vegetation model
Dury, Marie ULg; Hambuckers, Alain ULg; Trolliet, Franck ULg et al

Conference (2014, April)

The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are ... [more ▼]

The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are interesting alternatives to study those regions even if the lack of data often prevents sharp calibration and validation of the model projections. Dynamic vegetation models (DVMs) are process-based models that simulate shifts in potential vegetation and its associated biogeochemical and hydrological cycles in response to climate. Initially run at the global scale, DVMs can be run at any spatial scale provided that climate and soil data are available. In the framework of the BIOSERF project (“Sustainability of tropical forest biodiversity and services under climate and human pressure”), we use and adapt the CARAIB dynamic vegetation model (Dury et al., iForest - Biogeosciences and Forestry, 4:82-99, 2011) to study the Congo basin vegetation dynamics. The field campaigns have notably allowed the refinement of the vegetation representation from plant functional types (PFTs) to individual species through the collection of parameters such as the specific leaf area or the leaf C:N ratio of common tropical tree species and the location of their present-day occurrences from literature and available database. Here, we test the model ability to reproduce the present spatial and temporal variations of carbon stocks (e.g. biomass, soil carbon) and fluxes (e.g. gross and net primary productivities (GPP and NPP), net ecosystem production (NEP)) as well as the observed distribution of the studied species over the Congo basin. In the lack of abundant and long-term measurements, we compare model results with time series of remote sensing products (e.g. vegetation leaf area index (LAI), GPP and NPP). Several sensitivity tests are presented: we assess consecutively the impacts of the level at which the vegetation is simulated (PFTs or species), the spatial resolution and the initial land cover (potential or human-induced). First, we show simulations over the whole Congo basin at a 0.5◦ spatial resolution. Then, we present high-resolution simulations (1 km) carried out over different areas of the Congo basin, notably the DRC part of the WWF Lake Tele – Lake Tumba Landscape. Studied in the BIOSERF project, this area is characterized by a forest-savannah mosaic but also by swamp and flooded forest. In addition, forward transient projections of the model driven with the outputs of about thirty global cli- mate models (GCMs) from the new Coupled Model Intercomparison Project Phase 5 (CMIP5) will permit to outline the likely response of carbon pools to changing climate over the Congo basin during the 21th century. [less ▲]

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See detailModelling the Congo basin ecosystems with a dynamic vegetation model
Dury, Marie ULg; Hambuckers, Alain ULg; Trolliet, Franck ULg et al

Poster (2014, April)

The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are ... [more ▼]

The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are interesting alternatives to study those regions even if the lack of data often prevents sharp calibration and validation of the model projections. Dynamic vegetation models (DVMs) are process-based models that simulate shifts in potential vegetation and its associated biogeochemical and hydrological cycles in response to climate. Initially run at the global scale, DVMs can be run at any spatial scale provided that climate and soil data are available. In the framework of the BIOSERF project (“Sustainability of tropical forest biodiversity and services under climate and human pressure”), we use and adapt the CARAIB dynamic vegetation model (Dury et al., iForest - Biogeosciences and Forestry, 4:82-99, 2011) to study the Congo basin vegetation dynamics. The field campaigns have notably allowed the refinement of the vegetation representation from plant functional types (PFTs) to individual species through the collection of parameters such as the specific leaf area or the leaf C:N ratio of common tropical tree species and the location of their present-day occurrences from literature and available database. Here, we test the model ability to reproduce the present spatial and temporal variations of carbon stocks (e.g. biomass, soil carbon) and fluxes (e.g. gross and net primary productivities (GPP and NPP), net ecosystem production (NEP)) as well as the observed distribution of the studied species over the Congo basin. In the lack of abundant and long-term measurements, we compare model results with time series of remote sensing products (e.g. vegetation leaf area index (LAI), GPP and NPP). Several sensitivity tests are presented: we assess consecutively the impacts of the level at which the vegetation is simulated (PFTs or species), the spatial resolution and the initial land cover (potential or human-induced). First, we show simulations over the whole Congo basin at a 0.5◦ spatial resolution. Then, we present high-resolution simulations (1 km) carried out over different areas of the Congo basin, notably the DRC part of the WWF Lake Tele – Lake Tumba Landscape. Studied in the BIOSERF project, this area is characterized by a forest-savannah mosaic but also by swamp and flooded forest. In addition, forward transient projections of the model driven with the outputs of about thirty global cli- mate models (GCMs) from the new Coupled Model Intercomparison Project Phase 5 (CMIP5) will permit to outline the likely response of carbon pools to changing climate over the Congo basin during the 21th century. [less ▲]

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See detailModelling the distribution of key tree species used by lion tamarins in the Brazilian Atlantic forest under a scenario of future climate change
Raghunathan, N.; François, Louis ULg; Huynen, Marie-Claude ULg et al

in Regional Environmental Change (2014)

We used three IPCC climate change scenarios (A1B, A2 and B1) in a dynamic vegetation model (CARAIB), to determine the potential future distribution of 75 tree species used by two endemic primate species ... [more ▼]

We used three IPCC climate change scenarios (A1B, A2 and B1) in a dynamic vegetation model (CARAIB), to determine the potential future distribution of 75 tree species used by two endemic primate species from the Brazilian Atlantic Forest (BAF). Habitat conservation is a vital part of strategies to protect endangered species, and this is a new approach to understanding how key plant species needed for survival of golden lion tamarins (Leontopithecus rosalia) and golden-headed lion tamarins (L. chrysomelas) might be affected by climate change and what changes to their distribution are likely. The model accurately predicted the current distribution of BAF vegetation types, for 66 % of the individual tree species with 70 % agreement obtained for presence. In the simulation experiments for the future, 72 out of 75 tree species maintained more than 95 % of their original distribution and all species showed a range expansion. At the biome level, we note a substantial decrease in the sub-tropical forest area. There is some fragmentation of the savannah, which is encroached mostly by tropical seasonal forest. Where the current distribution shows a large sub-tropical forest biome, it has been replaced or encroached by tropical rainforest. The results suggested that the trees may benefit from an increase in temperature, if and only if soil water availability is not altered significantly, as was the case with climate simulations that were used. However, these results must be coupled with other information to maximise usefulness to conservation since BAF is already highly fragmented and subject to high anthropic pressure. © 2014 Springer-Verlag Berlin Heidelberg. [less ▲]

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See detailUse of camera traps for wildlife studies: a review
Trolliet, Franck ULg; Vermeulen, Cédric ULg; Huynen, Marie-Claude ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(3), 446-454

As human threats continue to impact natural habitats, there is an increasing need to regularly monitor the trends in large vertebrate populations. Conservation efforts must be directed appropriately, but ... [more ▼]

As human threats continue to impact natural habitats, there is an increasing need to regularly monitor the trends in large vertebrate populations. Conservation efforts must be directed appropriately, but field work necessary for data collection is often limited by time and availability of people. Camera traps are used as an efficient method to insure permanent sampling and to work in difficult to access areas. In the present study, we illustrate the way the use of camera traps developed: firstly with the need to monitor tiger (Panthera tigris (Linnaeus 1758)) populations and later as an instrument serving a diverse field of studies, such as animal behaviour and fauna-flora interaction. By looking at the material and technical aspects of various models of camera trap for implementation in different field studies in animal ecology, we highlight the need to choose appropriate camera trap models for the target species and to set up solid sampling protocols in order to successfully achieve study objectives. [less ▲]

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See detailDensity estimates and nesting-site selection in chimpanzees of the Nimba Mountains, Côte d'Ivoire and Guinea
Granier, Nicolas ULg; Hambuckers, Alain ULg; Matsuzawa et al

in American Journal of Primatology (2014)

We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked ... [more ▼]

We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked 80 km of transects and recces each month, and recorded 764 nests (mean group size = 2.23 nests) along with characteristics of vegetation structure and composition, topography and seasonality. Population density estimated with two nest count methods ranged between 0.14 and 0.65 chimpanzee/km2. These values are lower than previous estimates, emphasizing the necessity of protecting remaining wild ape populations. Chimpanzees built nests in 108 tree species out of 437 identified, but 2.3% of total species comprised 52% of nests. Despite they preferred nesting in trees of 25-29 cm DBH and at a mean height of 8.02 m, we recorded an important proportion of terrestrial nests (8.2%) that may reflect a cultural trait of Nimba chimpanzees. A logistic model of nest presence formulated as a function of 12 habitat variables revealed preference for gallery and mountain forests rather than lowland forest, and old-growth forest rather than secondary forests. They nested more frequently in the study area during the dry season (December-April). The highest probability of observing nests was at 770 m altitude, particularly in steep locations (mean ground declivity = 15.54%). Several of the reported nest characteristics combined with the existence of 2 geographically separated clusters of nest, suggest that the study area constitutes the non-overlapping peripheral areas of 2 distinct communities. This nest-based study led us to findings on the behavioral ecology of Nimba chimpanzees, which constitute crucial knowledge to implement efficient and purpose-built conservation. [less ▲]

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See detailCould bonobos, Pan paniscus, influence forest re(colonization) in a forest-savana mosaic?
Trolliet, Franck ULg; Serckx, Adeline ULg; Huynen, Marie-Claude ULg et al

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013, September 12)

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See detailInfluence of food resources on the ranging pattern of Northern pig-tailed macaques (Macaca leonina)
Albert, Aurelie; Huynen, Marie-Claude ULg; Savini, Tommaso et al

in International Journal of Primatology (2013)

Food availability may influence primates’ home range size and use. Understanding this relationship may facilitate the design of conservation strategies. We aimed to determine how fruit availability ... [more ▼]

Food availability may influence primates’ home range size and use. Understanding this relationship may facilitate the design of conservation strategies. We aimed to determine how fruit availability influences the ranging patterns of a group of northern pig-tailed macaques (Macaca leonina) living around the visitor center of Khao Yai National Park, Thailand. We predicted that macaques would increase their range during low fruit abundance periods to gather high-quality food and that they would go where there are more fruits or more fruits of particular species. We also predicted that human food, linked to human pre sence, would attract the macaques. We followed the macaques and recorded their diet and movements within their home range. We superimposed a grid on kernels defining the monthly home range surface to compare spatially macaques’ travel and the availability of fruits measured on botanical transects. Our results showed that the macaques increased their monthly home range in March, probably to obtain newly available fruits. During high fruit abundance seasons, they spent more time near particular fruit species. In August and September, although fruits became rare again, macaques kept their home range large, perhaps to find enough fruits as supplies dwindled. Finally, from October to February, they decreased their monthly home range size while consuming human food, a highquality item. In conclusion, the macaques used several ranging strategies according to fruit availability. however, we think that, without human food, macaques would tend to increase their range during low fruit abundance periods, as predicted. [less ▲]

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See detailInfluence of food resources on the ranging pattern of Northern pig-tailed macaques (Macaca leonina)
Albert, Aurelie; Huynen, Marie-Claude ULg; Savini, Tommaso et al

in International Journal of Primatology (2013)

Food availability may influence primates’ home range size and use. Understanding this relationship may facilitate the design of conservation strategies. We aimed to determine how fruit availability ... [more ▼]

Food availability may influence primates’ home range size and use. Understanding this relationship may facilitate the design of conservation strategies. We aimed to determine how fruit availability influences the ranging patterns of a group of northern pig-tailed macaques (Macaca leonina) living around the visitor center of Khao Yai National Park, Thailand. We predicted that macaques would increase their range during low fruit abundance periods to gather high-quality food and that they would go where there are more fruits or more fruits of particular species. We also predicted that human food, linked to human pre sence, would attract the macaques. We followed the macaques and recorded their diet and movements within their home range. We superimposed a grid on kernels defining the monthly home range surface to compare spatially macaques’ travel and the availability of fruits measured on botanical transects. Our results showed that the macaques increased their monthly home range in March, probably to obtain newly available fruits. During high fruit abundance seasons, they spent more time near particular fruit species. In August and September, although fruits became rare again, macaques kept their home range large, perhaps to find enough fruits as supplies dwindled. Finally, from October to February, they decreased their monthly home range size while consuming human food, a highquality item. In conclusion, the macaques used several ranging strategies according to fruit availability. however, we think that, without human food, macaques would tend to increase their range during low fruit abundance periods, as predicted. [less ▲]

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See detailDynamic of seed dispersal by large frugivores in a forest-savanna mosaic subject to anthropic pressure in Western D.R. Congo
Trolliet, Franck ULg; Serckx, Adeline ULg; Huynen, Marie-Claude ULg et al

Poster (2013, April 05)

The Western Congolian forest-savanna mosaic is an ecotone subject to anthropogenic as well as natural fragmentation. Its forests have thus a considerable proportion of edges. This vegetation structure is ... [more ▼]

The Western Congolian forest-savanna mosaic is an ecotone subject to anthropogenic as well as natural fragmentation. Its forests have thus a considerable proportion of edges. This vegetation structure is likely to impact animal and plant communities and its dynamics such as animal mediated seed dispersal. Synergetically, activities such as bush meat hunting deplete large frugivores populations and thus decrease recruitment potential of the plants they disperse. Indeed, zoochory is known to be of great importance for tropical forests and a number of studies proved that large-seeded tree species closely depend on large frugivores for their regeneration. In such a context, we aim to understand how forest edges affect the dynamics of seed dispersal. More precisely, we wonder if the interactions between large seeds and their dispersers and predators are affected when closer to edges and how this can impact plant regeneration capacity. Also, we wonder if the dispersal and regeneration of large-seeded tree species depend on a few disproportionally important frugivores species. Bonobos, Pan paniscus, are among the largest frugivores left in the area and thus likely to be disproportionally important seed dispersers, though, their role as seed dispersers has yet been little investigated. We thus focus on the qualitative role for seed dispersal of the potentially keystone and umbrella ape species, the bonobo. To answer those questions, we study the main steps characteristics of large-seeded tree species regeneration process; namely quantitative seed dispersal, seed deposition pattern, germination capacity after transit in frugivore’s gut and, seed and seedling fate. By studying five different tree species at varying distances from forest edge, we aim to drive an inter-species comparison and to highlight the effect of forest edge on the regeneration process. We first quantify the seed production for each tree species and then evaluate the quantitative capacity of seed dispersal. By combining direct focal observations and camera trapping, we are able to highlight variations in composition of dispersers community and their respective contribution to seed dispersal. A literature review on each disperser species’ seed retention time and habitat use will allow the computation of the seed dispersal kernels. We will also evaluate the effect of seed ingestion by the bonobo on its germination capacity: seeds will be collected from dung to evaluate the effect of seed ingestion on the rate and velocity of germination. Finally, we will study the predation pressure exerted on dispersed and non-dispersed seeds and seedlings by setting up two sets of seeds below the canopy of parent trees and away from any conspecific trees. One set will be dispersed unprotected to seed predators; another one will be enclosed in a cage and permit seeds to germinate, allowing us to evaluate the herbivores pressure on seedlings. [less ▲]

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See detailFrugivory and seed dispersal by northern pigtailed macaques, Macaca leonina, in Thailand
Albert, Aurélie; Hambuckers, Alain ULg; Culot, Laurence ULg et al

in International Journal of Primatology (2013), 33

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See detailInventaire malacologique du domaine forestier universitaire du Sart Tilman (Liège, Belgique)
Léonard, Lilian; Delcourt, Johann ULg; Vilvens, Claude et al

Report (2013)

The Sart Tilman is a vast wooded area of 754 ha located on the south of the city of Liege that hosts the campus of the University of Liege. It is the only large remaining peri-urban forest of this city ... [more ▼]

The Sart Tilman is a vast wooded area of 754 ha located on the south of the city of Liege that hosts the campus of the University of Liege. It is the only large remaining peri-urban forest of this city. The installation of the University in this place was planned in order to discard the threads of real estate business. The absence of major silvicultural treatments for over 50 years has allowed the forest gradually recovering some dynamics of a natural ecosystem although its composition remains largely influenced by past management. Its interest as multi-use area and particularly as a biodiversity reserve is recognized. Nevertheless, internal pressures similar to urbanization spread threaten the integrity of the area. The Scientific Council of the Sites of the Sart Tilman, which is in charge of maintaining the integrity, and promoting the scientific, educational, and aesthetic development of the area, would like to dispose of more biodiversity distribution data to carry on its missions. The present study is an analysis of the malacological diversity of Sart Tilman taking into account the diversity of forest stands. The work began with the design and evaluation of an effective protocol to allow a malacological inventory in the most comprehensive manner as possible. An inventory protocol combining three methods has been applied to the field with a stratified sample strategy taking into account forest type. The inventory reports a list of 43 species and estimates that 5 to 7 additional species are potentially present. The diversity was modelled as a function of environmental descriptors. Models show meaningful effects of drainage, soil pH, and forest type on the richness and species diversity. However, the predictive ability of these models is insufficient to directly predict malacological diversity and to establish scale mapping of the Sart Tilman. Otherwise, malacological diversity is correlated with an index of potential biodiversity resulting from the combination of 10 easily observable indicators like the number of native tree species or the stratification of the stands. [less ▲]

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See detailModelling the risk of ecosystem disruption in Europe with a dynamic vegetation model
Dury, Marie ULg; Hambuckers, Alain ULg; Warnant, Pierre et al

Conference (2012, April)

What will be the European ecosystem responses to future climate? With unprecedented speed and extent, the projected climate change might lead to a disruption of terrestrial plants functioning in many ... [more ▼]

What will be the European ecosystem responses to future climate? With unprecedented speed and extent, the projected climate change might lead to a disruption of terrestrial plants functioning in many regions. In the framework of the EcoChange project, transient projections over the 1901-2100 period have been performed with a process-based dynamic vegetation model, CARAIB DVM (Dury et al., 2011, iForest 4: 82, 99). The vegetation model was driven by the outputs of four climate models under the SRES A1B scenario: the ARPEGE/Climate model and three regional climate models (KNMI-RACMO2 , DMI-HIRHAM5 and HC-HadRM3Q0 RCMs) from the European Union project ENSEMBLES. DVMs are appropriate tools to apprehend potential climate change impacts on ecosystems and identify threatened regions over Europe. CARAIB outputs (soil moisture, runoff, net primary productivity, fire, etc.) were used to characterize the ecosystem evolution. To assess consequences on biodiversity, the evolution of 100 natural common European species (47 herbs, 12 shrubs and 41 trees) has been studied year-to-year over the 1901-2100 period. Under the combined effects of projected changes particularly in temperature and precipitations, CARAIB simulates important reductions in the annual soil water content. The species productivities vary strongly from year to year reaching during the driest years values much lower than present-day average productivity. According to CARAIB, a lot of species might go beyond their water tolerance very frequently, particularly after 2050, due to more intense summer droughts. In the northern part of Europe and in the Alps, with reduced temperature variability and positive soil water anomalies, NPP variability tends to decrease. Regions with more severe droughts might also be affected by an increase of the frequency and intensity of wildfires. With this background, the species distributions might be strongly modified. 15% of tree species and 30% of herb and shrub species (respectively 30% and 60% if the CO2 fertilization effect on species is not taken into account) might experience a loss of 30% or more of their current distribution. Proportions of new species appearance at the end of the century were also studied. Southern Europe might suffer important species extinction while the more suitable climate conditions in northern Europe might lead to a gain in species diversity. [less ▲]

Detailed reference viewed: 49 (17 ULg)
Peer Reviewed
See detailDispersal and regeneration capacity of large-seeded tree species in a forest-savanna mosaic in Western DR Congo
Trolliet, Franck ULg; Huynen, Marie-Claude ULg; Hambuckers, Alain ULg

Poster (2012)

It is widely recognized that the Congo Basin is affected by numerous anthropogenic pressures. A number of studies proved that hunting and forest fragmentation diminish the diversity and abundance of large ... [more ▼]

It is widely recognized that the Congo Basin is affected by numerous anthropogenic pressures. A number of studies proved that hunting and forest fragmentation diminish the diversity and abundance of large vertebrates, more specifically, of large frugivores. The depletion of those animals can directly affect large-seeded tree species as large seeds closely depend on the community of large frugivorous vertebrates for their dispersal. Then, the disruption of animal mediated seed dispersal is thought to deeply impact the plant regeneration capacity. The forest-savanna mosaic situated in Western DR Congo is an ecotone characterized by naturally occurring forest fragments which are also subject to numerous anthropogenic pressures. Those are very likely to disrupt seed dispersal mechanisms and to alter forest regeneration processes. To date, few studies have considered the effect of such an ecosystem on plant-animal interaction dynamics such as seed dispersal, and none have been done in this region. This study will examine if the early stages of regeneration of the large-seeded tree species Anonidium mannii, namely the dispersal capacity and seedling establishment is affected by forest fragment size. We predict that the small fragment size will negatively affect the regeneration capacity of this species. To test this assumption, we will work along a gradient of forest fragment sizes to define the composition of the seed disperser communities. For each disperser assemblage, we will evaluate the quantitative capacity of seed dispersal by combining direct focal observations and camera trapping. A literature review on each disperser species seed retention time and habitat use will allow the computation of the seed dispersal kernels. We will also evaluate the effect of seed ingestion by a presumably important seed disperser, the bonobo, Pan paniscus, on its germination capacity. Seeds will be collected from dung to evaluate the effect of seed ingestion on the rate and velocity of germination. Finally, we will study the predation pressure exerted on dispersed and non-dispersed seeds and seedlings by setting up two sets of seeds below the canopy of parent trees and away from any conspecific trees. One set will be dispersed unprotected to seed predators; another one will be enclosed in a cage and permit seeds to germinate, allowing us to evaluate the herbivores pressure on seedlings. [less ▲]

Detailed reference viewed: 92 (14 ULg)
See detailUne approche participative des interactions entre les hommes, femmes et la biodiversité de la forêt tropicale dans la région du lac Tumba, RDC
Halleux, C.; Dendoncker, N.; Huynen, Marie-Claude ULg et al

Conference (2012)

L'objectif du projet BIOSERF est d'évaluer la durabilité d'un écosystème de forêt tropicale humide dans l'Ouest de la République démocratique du Congo sous des pressions démographiques, sociétales et ... [more ▼]

L'objectif du projet BIOSERF est d'évaluer la durabilité d'un écosystème de forêt tropicale humide dans l'Ouest de la République démocratique du Congo sous des pressions démographiques, sociétales et climatiques. Le projet se concentre sur les interactions entre la flore, la faune et la population humaine locale pour comprendre les processus modifiant la biodiversité et la disponibilité en services écosystémiques dans des zones tropicales humides. En collaboration étroite avec une ONG locale, il utilisera un modèle de végétation dynamique (CARAIB) qui sera associé à un modèle multi-agents, afin d'analyser l'utilisation de différents services écosystémiques comme par exemple la production de plantes médicinales, de bois et d'autres produits forestiers, ou de services liés à la création de réserves naturelles. Le modèle de végétation sera adapté pour prendre en compte les processus de régénération de plusieurs espèces de plantes, sélectionnées pour leur usage par les communautés humaines locales. Pour ce faire, une sélection de 5 espèces d'arbres utilisées fréquemment ou traditionnellement sera effectuée basée sur les résultats d'une enquête sociologique. Une étude combinée des communautés de disperseurs de graines permettra de prendre en compte leur rôle dans la régénération de la forêt. Le modèle multi-agents, quant à lui, devrait voir le jour lors d'un processus de modélisation d'accompagnement. Toutes les hypothèses de base de la modélisation peuvent être remises en cause durant le processus, au contact de la réalité du terrain. Cette méthode devrait permettre de mettre en débat les incertitudes liées à la notion de service écosystémique. A travers une approche post-normale, cette démarche de modélisation a pour vocation de faire dialoguer scientifiques, citoyens et décideurs et ceci afin d'améliorer la qualité du processus de prise de décision collective. La conception de différents scénarios permettra d'explorer différentes pistes de futurs possibles et/ou désirables. [less ▲]

Detailed reference viewed: 89 (7 ULg)