References of "Lejeune, Philippe"
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See detailFine-scale analysis of ungulate-vehicle collisions in Southern Belgium
maron, Julie; Lehaire, François ULg; Morelle, Kevin ULg et al

Poster (2013, August)

Ungulate-vehicle collisions (UVC) are an increasing phenomenon in many European countries. These road accidents are a threat to wildlife populations but also to human safety and generate high economic ... [more ▼]

Ungulate-vehicle collisions (UVC) are an increasing phenomenon in many European countries. These road accidents are a threat to wildlife populations but also to human safety and generate high economic costs. Wallonia, the Southern part of Belgium, is also affected by the UVC problem and offers an interesting study area because of its very dense road network and increasing big game populations. The aim of our study was to determine where and when UVC hotspots occurred along highways in Wallonia, in order to provide recommendations regarding the location and design of mitigation measures. The study site is located in Wallonia (Southern Belgium) in the provinces of Liege and Namur (5,875 km²). Ungulates species present in this area are wild boar, roe deer and red deer. The UVC data were collected by the police and covered the period between 2008 and 2011 (n= 2,704). We analyzed the landscape and road-related variables of sections with high UVC risk in contrast with section of low risk. The landscape and road-related variables related to the location of UVC were highlighted using a generalized linear model (GLM) with simulated pseudo-absences. Concerning traffic accidents, the most involved game species are wild boar (37% of all casualties). That’s why the amount of data on wild boar was higher than for the other species. The results of the spatial and temporal analysis of wild boar-vehicle collisions (WVC) are therefore more accurate than for the other species. Consequently we decided to focused on the wild boar in the present poster. Temporal analysis showed strong variations in the WVC frequency over time, on the daily and seasonal scale. These critical periods correspond to the activity periods of the species (more UVC at night and during autumn and winter). The study also points out a negative correlation between the occurrence of UVC and the traffic volume (R² = 9.79%). This result doesn’t match with the literature but can be explained if we assume that when traffic increase, the road represents a more impassable barrier for animal species. As expected we also noticed a positive correlation between game density and UVC risk. These results indicate clear spatial and temporal clustering of WVC. Identification of hotspots enables us to identify the priority areas where mitigation measures must be considered. For further research, the accuracy of the police data should be improved in order to predict more exactly the risk of UVC. This would also make the mitigation measures more cost-effective. [less ▲]

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See detailWild boar movement ecology: what do we (don’t) know ?
Morelle, Kevin ULg; Prévot, Céline; Lehaire, François ULg et al

Poster (2013, August)

Although subject of many researches since decades, movement studies have been recently enhanced by the emergence of the movement ecology paradigm (Nathan 2008). Under this paradigm, Nathan et al. (2008 ... [more ▼]

Although subject of many researches since decades, movement studies have been recently enhanced by the emergence of the movement ecology paradigm (Nathan 2008). Under this paradigm, Nathan et al. (2008) proposed to break down movement of animal into four basic mechanistic components: i) internal states (motivation, physiology, why to move ?), ii) motion capacities (how to move ?), iii) navigation capacities and (when and where to move ?) and iv) external factors (physical environment and living organisms – conspecifics or not). Considering these four components of an individual’s movement, we reviewed literature dealing with wild boar (Sus scrofa L.), a species of important ecological and socio-economic concern, and tried to identify the key processes influencing this species’ movement. We conclude this review of the literature by highlighting the gaps in movement ecology of wild boar and suggesting further research directions under the light of the most recent used techniques. [less ▲]

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See detailSpatial analysis of bark-stripping damage by red deer in irregular hardwood forest
Lehaire, François ULg; Mercier, Grégoire; Lejeune, Philippe ULg

Poster (2013, August)

Over the past years, the population size of red deer (Cervus elaphus L.) is following an upward trend in Wallonia. This has led to an increased pressure on vegetation as well as to forest damages of ... [more ▼]

Over the past years, the population size of red deer (Cervus elaphus L.) is following an upward trend in Wallonia. This has led to an increased pressure on vegetation as well as to forest damages of greater frequency and intensity. Among these damages, bark-stripping can be especially harmful to the timber quality due to the development of rot. The impact of these populations may thus lead to a reduction in forest productivity and to economic losses. Nevertheless, these damages doesn’t depend only on the density of red deer but also on the environmental characteristics of their habitats. The main objective of this study is to perform a spatial analysis of the occurrence of bark stripping in order to identify the environmental factor that affect the occurrence of the damages in hardwood forests. The bark-stripping damages in coniferous stands are well-known due to the fact that they are relatively frequent. Such information is however unavailable for hardwood stands. The study site (6500 hectares) is located in the Ardennes in Southern Belgium (Wallonia) and is mainly composed of beech stands. We used data of inventory campaigns that were carried out for management purposes. In each sampling unit (total of 321 units), we measured different stand characteristics and, during a second phase, the bark-stripping damages. These latter measurements concerned the presence or absence of bark-stripping on each recorded stem and damage age (presence or not of a healing roll). Only trees with dbh greater than 5 cm were taken into account. All the data were collected in hardwood stands. To perform the spatial analysis, a set of environmental variables, including landscape (distances to the natural or artificial feeding points, to watering-place, to the different types of road and to the forest paths, to refuge areas for deer and to forest edges, etc.) and tree dimension variables, have been collected. The estimated red deer density was also took into account. All these variables have been included in a fixed linear model using stepwise regression. An angular transformation was applied in order to guarantee appropriate conditions of application of the linear regressions. Over one hundred variables were tested but only six of them have a significant impact on the bark-stripping rate. This model explains only 10,2% of the bark-stripping rate. Tree dimension variables explain most of the bark-stripping rate. Thus, forest structure has an important impact on the bark-stripping probability. The roads and the human activities in general can have an impact on the bark-stripping rate. These activities can disturb the red deer feeding periods during the day and lead to important bark-stripping damages. We expected to observe other variables contributing to the model such as red deer density and altitude. The absence of effect of altitude can be explained by the fact that bark-stripping of beech trees occurs mainly in summer. The scale of the study can explain the absence of red deer density. [less ▲]

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See detailBioindicators for measurement of red deer pressure on understory vegetation in temperate deciduous forests
Lehaire, François ULg; Morelle, Kevin ULg; Ligot, Gauthier ULg et al

Poster (2013, August)

During the last decades, populations of large herbivores have largely increased. Consequently, their pressure on forest vegetation has been exacerbated, reaching in some cases levels that reduced the ... [more ▼]

During the last decades, populations of large herbivores have largely increased. Consequently, their pressure on forest vegetation has been exacerbated, reaching in some cases levels that reduced the diversity of forest ecosystem services. Assessing the balance between timber production and hunting activities remains a crucial question for forest managers who hence need reliable tools such as ecological indicators. Our aim was to review ecological indicators that characterize the pressure of red deer (Cervus elaphus L.) on understory vegetation in temperate deciduous forest ecosystem. The choice of plants on which the variables are measured is crucial to accurately characterize the deer pressure. This choice must take into account the feeding behavior of red deer, silvicultural objectives, ease of the measurement and the occurrence of these plants within the studied habitat. Generally, it is more appropriate to use common species with a wide ecological amplitude. The choice of indicator plants must take into account plant abundance and palatability, as they both affects considerably the performance of the ecological indicator. The variability of indicators generally increases with the scarcity of the chosen indicator plant. Therefore, choosing abundant plant species appear often the best solution as the resulting have a lower variability and hence enable better to detect changes of deer pressure. At low herbivore pressure, palatable species to offer quick response to the pressure variations. Palatable species are therefore reliable plant indicator especially if these is a good balance between game population and forestry. At excessive herbivore pressure, non-palatable species are preferred. In this case, the variability of ecological indicator is smaller with non palatable plant than with palatable plant. Ecological indicators of deer pressure help to understand the relationships between biodiversity, carrying capacity and deer populations. They are intended to forest managers that would like to monitor red deer pressure in regards to forest management goals and forest sustainability. [less ▲]

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See detailAssessment and monitoring of forest-game balance: an exclosure experiment
Lehaire, François ULg; Licoppe, Alain ULg; Lejeune, Philippe ULg

Poster (2013, August)

During the last decades, populations of large ungulates have largely increased, strengthening the pressure exerted by these species on forest vegetation. Therefore, monitoring this pressure has become ... [more ▼]

During the last decades, populations of large ungulates have largely increased, strengthening the pressure exerted by these species on forest vegetation. Therefore, monitoring this pressure has become unavoidable for sustainable forest management. Such monitoring requires a rigorous approach in order to evaluate objectively the balance between game population and forestry. The use of exclosure experiment offers an interesting solution to observe the effects of game populations on forest ecosystem. When objectives expected from forest management are clearly defined, exclosure experiments can effectively be used as a monitoring tool, to allow detecting unbalanced situations, for example, herbivore pressure threatening forest regeneration. The monitoring tool combines on one side an exclosure, defined as "the real environment", fully accessible to herbivores and, on the other side an enclosure, which is the "control treatment", fenced and therefore unavailable to any large ungulates. Our main aim was to compute a set of indicators characterizing the ecological changes due to large herbivores pressure on forest ecosystems. We identified 2 categories of ecological indicators: the short-term and the medium-term indicators. Short-term indicators require only two-year of monitoring to correctly quantify herbivore pressure whereas medium-term indicators require at least 4 years of monitoring. The study site is located in Southern Belgium (Wallonia), in mixed beech and oak forests. The predominant vegetation type is the "Luzulo-Fagetum", typically found in acidophileous beech forests. The ungulate species of interest are red deer, roe deer, wild boar and mouflon. In 2006, enclosures and exclosures (4 x 4 m) were installed in 17 sites scattered in two zones with contrasted deer densities to assess indicators efficiency. Between 2006 and 2012, we performed floristic surveys and we recorded the height, density and cover of the understory vegetation of every plot. [less ▲]

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See detailSynthesis and new definition of the areas included in the urban-rural gradient
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

Conference (2013, July 26)

Every scientific studies should begin with the delimitation of the studied system. Ours aims at evaluating and quantifying the resistence of landscape classes and ecosystems to the urbanization process ... [more ▼]

Every scientific studies should begin with the delimitation of the studied system. Ours aims at evaluating and quantifying the resistence of landscape classes and ecosystems to the urbanization process. This is done by studying a dozen cities in sub-Saharan Africa, conducting a diachronic (2000 - 2010) landscape evolution analysis from SPOT satellite imagery. Paradoxaly, when tackling this subject, one must recognize that no consensus exists about the definition and localization of the areas included in the urban-rural gradient. This prevents from comparing the results of different cities. A bibliography analysis has been conducted in order to 1) identify the different areas in the urban-rural gradient, the characteristics and types of characteristics used to define the most cited ones (i.e. urban, suburbs, sprawl, exurban, rurban, periurban and rural) ; 2) Through citation frequency indexes, evaluate the relative importance of characteristics and types of characteristics for every area and then for the whole gradient; 3) Evaluate the principal characteristics according to a series of criteria (the best characteristic is supposed to be quantitative, integrative, marking a consensus, discriminative and easy to apply on the field); 4) On the basis of retained characteristics, propose single and simple definitions to the most cited areas. These new definitions aim at enable areas identification on the field and on satellite images. These new definitions have been applied to the field study of the city of Lubumbashi (D.R.C) and seem to be convenient. Retained characteristics have then been translated into landscape composition indexes for the future study of the following cities on basis of satellite imagery, without field research. Indeed, such indexes are commonly used in landscape ecology because they allow the description of the urban landscape pattern or structure which, according to the central hypothesis of landscape ecology, i.e. “pattern-process paradigm”, influence landscape ecological processes. [less ▲]

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See detailLES ENCLOS-EXCLOS : UNE TECHNIQUE ÉPROUVÉE POUR L’ÉVALUATION ET LE MONITORING DE L’ÉQUILIBRE FORÊT-GRANDE FAUNE
Lehaire, François ULg; Morelle, Kevin ULg; Licoppe, Alain ULg et al

in Forêt Wallonne (2013), 125

During the last decades, populations of large ungulate herbivores have increased and their influence on forest vegetation have been clearly highlighted. Therefore, monitoring game pressure have become ... [more ▼]

During the last decades, populations of large ungulate herbivores have increased and their influence on forest vegetation have been clearly highlighted. Therefore, monitoring game pressure have become unavoidable for sustainable forest management. Such monitoring require a rigorous approach in order to evaluate objectively the forest-game balance. Under these conditions, the use of exclosure experiment has appeared an interesting solution. They enable to observe the ecosystem evolution due to forest-game imbalance as well as to detect any early deterioration of a situation that was initially considered acceptable. The enclosure-exclosure devices compare, on the one hand, the real environment (exclosure) fully accessible by wildlife and, secondly, a “control” fenced habitat (enclosures) inaccessible to all populations of large ungulates (e.g. wild boar, red deer, roe deer and mouflon). In 2006, enclosure-exclosure devices (4 x 4 m) were installed within forest gaps in order to monitore the understory dynamic in Wallonia. Observations were collected until 2012 and we computed a set of indicators characterizing the ecological changes due to large herbivores pressure on forest ecosystems. Such devices played a key educational role as it provide a visual comparison of two contrasted situations. Additionally, quantitative information were collected to perform further analysis (floristic survey, as well as height, number of stems and the cover of vegetation). We identified indicators of the ecological changes that responded within two years whereas other indicators required at least 4 monitoring years in order to quantify correctly herbivore pressure. Short-term indicators allow a rapid detection, but they have the disadvantage of being very sensitive to exogenous factors (climate changes, site conditions). At the opposite, medium-term indicators, such as regeneration growth, require a longer monitoring period, but they are more robust (mitigation interannual variations of environmental factors) than the short-term indicators. We evaluated the relative efficiency of various indicators using 17 enclosures distributed in two zones with contrasted deer densities. Some of the tested indicators allowed detecting significant differences between the two zones (Student's t test). In particular, among the short-term indicators we obtained significant result with the ground vegetation richness, regeneration richness, seedling density and height of Rubus fruticosus L. and Rubus idaeus L.. Among the medium-term indicators, the most relevant indicators were the average height of beech and birch, ground vegetation richness, seedling density and total cover of vegetation. [less ▲]

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See detailHow closely are Pericopsis elata (Fabaceae) patches linked to past human disturbances in South-Eastern Cameroon
Bourland, Nils ULg; Cerisier, François; Daïnou, Kasso ULg et al

Conference (2013, June 26)

Studies conducted in the Congo Basin forests concluded that soil parameters and large disturbances induced by human activities since 3000–2000 BP could be the main driver for the persistence of long lived ... [more ▼]

Studies conducted in the Congo Basin forests concluded that soil parameters and large disturbances induced by human activities since 3000–2000 BP could be the main driver for the persistence of long lived light-demanding tall tree species. Today most of the timber species belong to this group, among them Pericopsis elata (Fabaceae). Like many other light-demanding trees, this species suffers from important regeneration problems. While the conditions for its establishment must have been met in the past, they obviously have become unfavourable. Because of ongoing logging activities and a natural decline of its populations, this species is recorded in both the IUCN Red List and the CITES Appendix II listings. Our goal was to investigate the roles of both pedological and anthropogenic factors in the persistence of forest patches characterized by this clustered species. Soil surveys, botanical inventories and anthracological excavations were conducted in three different forest sites located in south-eastern Cameroon. P. elata patches (3.3-14.7 ha) were studied and compared to their close surroundings. No statistical differences were observed between the results of botanical inventories conducted inside and outside the patches (Morisita-Horn indices from 0.69-0.77). Soils only differed in Fe content, but otherwise no significant differences could be observed. Charcoal is widespread and abundant in study sites, mostly inside the patches. Charcoal radiocarbon dating (2,150-195 BP) was consistent with decoration techniques of archaeological materials that we discovered. The average age of P. elata individuals coincides with fire events that occurred in a region where fires rarely occur naturally. We present evidence of past anthropogenic disturbances (human settlement, slash-and-burn cultivation) in the Congolese mixed moist semi-evergreen forest in south-eastern Cameroon. We discuss the potential influence of our findings on the management of light-demanding tall trees populations in a context of logging activities. [less ▲]

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See detailAfzelia populations, a poorly known species complex of timber trees from African tropical forests
Donkpegan, Segbedji ULg; Hardy, Olivier; Daïnou, Kasso ULg et al

Scientific conference (2013, June 26)

The fate of African tropical forests is a major concern for conservation, while their biodiversity is still poorly known. The purpose of this poster is to provide an update of knowledge of the genus ... [more ▼]

The fate of African tropical forests is a major concern for conservation, while their biodiversity is still poorly known. The purpose of this poster is to provide an update of knowledge of the genus Afzelia, a complex of sister tree species exploited for their wood in central Africa. The distribution of Afzelia in Africa suggests various adaptations to ecological factors. In fact, most of Afzelia species occur in parapatry and are so similar that they are often not distinguished by logging companies and forests managers. We show that the genus remains understudied in Africa although some of its species are considered as endangered or vulnerable. Therefore, a revision of its taxonomy along with thorough investigations of ecological and genetic aspects of Afzelia populations, using molecular markers currently in development (nSSR, cpDNA and nDNA), should be relevant and of great interest for conservation and sustainable management purposes. We will describe the different and complementary morpho-genetic approaches that will be used to investigate the biogeographical history of Afzeliapopulation in concert with species boundary questions. [less ▲]

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See detailModelling the top-height growth and site index of Norway spruce in Southern Belgium
Perin, Jérôme ULg; Hebert, Jacques ULg; Brostaux, Yves ULg et al

in Forest Ecology & Management (2013), 298

Top-height growth in even-aged stands of Norway spruce (Piceaabies (L.) Karst.) from Southern Belgium was modelled using functions which provide an algebraic solution for site index (SI) calculation. 16 ... [more ▼]

Top-height growth in even-aged stands of Norway spruce (Piceaabies (L.) Karst.) from Southern Belgium was modelled using functions which provide an algebraic solution for site index (SI) calculation. 16 well known growth model formulations were parameterized using a method which accounts for heterogeneous variance and autocorrelation on a dataset composed of stem analysis data completed by measuring the heights of all the branch whorls to allow for accurate height–age estimates. Comparison of the parameterized models showed that the oblique asymptotic function known as the Duplat and Tran-Ha III model was the most efficient on our dataset. Validation of the selected model on permanent sample plot data showed no evidence of bias over the full range of possible age, height, site index and densities encountered in Norway spruce stands of Southern Belgium. The new height growth model described represents a significant improvement over the previous model of Dagnelie et al. (1988), which was found to be unreliable and required the use of an iterative process to estimate SI. [less ▲]

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See detailGradient urbain-rural de la ville de Lubumbashi: dynamique entre 2002 et 2009
Andre, Marie ULg; Bogaert, Jan ULg; Mahy, Grégory ULg et al

in Ernoult, Aude (Ed.) Dynamiques écologiques des paysages: de l'agricole à l'urbain (2013, June 12)

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See detailDescription of a new procedure to estimate the carbon stocks of all forest pools and impact assessment of methodological choices on the estimates
Latte, Nicolas ULg; Colinet, Gilles ULg; Fayolle, Adeline ULg et al

in European Journal of Forest Research (2013), 132

Forest ecosystems play a major role in atmospheric carbon sequestration and emission. Comparable organic carbon stock estimates at temporal and spatial scales for all forest pools are needed for ... [more ▼]

Forest ecosystems play a major role in atmospheric carbon sequestration and emission. Comparable organic carbon stock estimates at temporal and spatial scales for all forest pools are needed for scientific investigations and political purposes. Therefore, we developed a new carbon stock (CS) estimation procedure that combines forest inventory and soil and litter geodatabases at a regional scale (southern Belgium). This procedure can be implemented in other regions and countries on condition that available external carbon soil and litter data can be linked to forest inventory plots. The presented procedure includes a specific CS estimation method for each of the following forest pools and subpools (in brackets): living biomass (aboveground and belowground), deadwood (dead trees and snags, coarse woody debris and stumps), litter, and soil. The total CS of the forest was estimated at 86 Tg (185 Mg ha-1). Soil up to 0.2 m depth, living biomass, litter, and deadwood CSs account, respectively, for 48, 47, 4, and 1 % of the total CS. The analysis of the CS variation within the pools across ecoregions and forest types revealed in particular that: (1) the living biomass CS of broadleaved forests exceeds that of coniferous forests, (2) the soil and litter CSs of coniferous forest exceed those of broadleaved forests, and (3) beech stands come at the top in carbon stocking capacity. Because our estimates differ sometimes significantly from the previous studies, we compared different methods and their impacts on the estimates. We demonstrated that estimates may vary highly, from -16 to ?12 %, depending on the selected methods. Methodological choices are thus essential especially for estimating CO2 fluxes by the stock change approach. The sources of error and the accuracy of the estimates were discussed extensively. [less ▲]

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See detailSpecies delimitation and diversification in the widespread tree genus Milicia (Moraceae)
Daïnou, Kasso ULg; Mahy, Grégory ULg; Duminil, Jérôme et al

Conference (2013, June)

The long generation time and large effective size of widespread forest tree species can result in slow evolutionary rate and incomplete lineage sorting, complicating species delimitation. We addressed ... [more ▼]

The long generation time and large effective size of widespread forest tree species can result in slow evolutionary rate and incomplete lineage sorting, complicating species delimitation. We addressed this issue with the African timber tree genus Milicia that comprises two morphologically similar and often confounded species: M. excelsa, widespread from West to East Africa, and M. regia, endemic to West Africa. We combined information from nuclear microsatellites (nSSRs), nuclear and plastid DNA sequences, and morphological systematics to identify significant evolutionary units and infer their evolutionary and biogeographical history. We detected five geographically coherent genetic clusters using nSSRs and three levels of genetic differentiation. First, one West African cluster matched perfectly with the morphospecies M. regia, which formed a monophyletic clade at both DNA sequences. Second, a West African M. excelsa cluster formed a monophyletic group at plastid DNA and was more related to M. regia than to Central African M. excelsa, but shared many haplotypes with the latter at nuclear DNA. Third, three Central African clusters appeared little differentiated and shared most of their haplotypes. Although gene tree paraphyly could suggest a single species in Milicia following the Phylogenetic Species Concept, the existence of mutual haplotypic exclusivity and non-admixed genetic clusters in the contact area of the two taxa indicate strong reproductive isolation, and thus, two species following the Biological Species Concept. Molecular dating of the first divergence events showed that speciation in Milicia is ancient (Tertiary), indicating that long-living tree taxa exhibiting genetic speciation may remain similar morphologically. [less ▲]

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See detailPrincipes de base de la télédétection et ses potentialités comme outil de caractérisation de la ressource forestière – II. LiDAR aérien
Bonnet, Stéphanie ULg; Toromanoff, François ULg; Bauwens, Sébastien ULg et al

in Forêt Wallonne (2013), (124), 28-41

La télédétection a déjà démontré, au travers de nombreuses études, son potentiel de caractérisation de la ressource forestière. En particulier, le développement du LiDAR aérien a ouvert la voie à de ... [more ▼]

La télédétection a déjà démontré, au travers de nombreuses études, son potentiel de caractérisation de la ressource forestière. En particulier, le développement du LiDAR aérien a ouvert la voie à de nouvelles perspectives. Cette technologie offre une vision tridimensionnelle de la forêt qui permet de récolter à large échelle des informations à l'intérieur même des peuplements. Après avoir présenté les grands principes de télédétection dans un premier article (Forêt Wallonne n°114), ce second volet présente quelques concepts de base pour se familiariser avec le LiDAR et illustre son intérêt pour la gestion des forêts et des milieux naturels aux travers de travaux de recherche menés sur une zone pilote constituée par le bassin versant de la Houille dans la région de Gedinne en Province de Namur. [less ▲]

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See detailLa photogrammétrie: un procédé pour mesurer les arbres à troncs irréguliers
Bauwens, Sébastien ULg; Fayolle, Adeline ULg; Nzenga, Alide Kidimbu et al

Conference (2013, April)

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See detailLes équations allométriques pan-tropicales plurispécifiques sont-elles valables en Afrique centrale ?
Fayolle, Adeline ULg; Doucet, Jean-Louis ULg; Gillet, Jean-François ULg et al

in Picard, Nicolas; Henry, Mathieu (Eds.) Compte-rendu de l'Atelier scientifique régional sur les équations allométriques en Afrique Centrale : PREREDD, Yaoundé 2-5 avril 2013 (2013, April)

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See detailCollisions entre véhicules et animaux en liberté : état des lieux à partir d'une enquête au sein de la police
Lehaire, François ULg; Morelle, Kevin ULg; Lejeune, Philippe ULg

in Forêt Wallonne (2013), 122

Les accidents de la route impliquant des animaux sauvages sont de plus en plus nombreux. En se basant sur les données recueillies par les zones de police en Wallonie, il est possible d’avoir une vision ... [more ▼]

Les accidents de la route impliquant des animaux sauvages sont de plus en plus nombreux. En se basant sur les données recueillies par les zones de police en Wallonie, il est possible d’avoir une vision plus claire de la problématique. Dans le cas du cerf et du sanglier, il apparaît clairement que la hausse des accidents est liée à l’augmentation de leurs populations. [less ▲]

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See detailUnmanned aerial survey of elephants
Vermeulen, Cédric ULg; Lejeune, Philippe ULg; Lisein, Jonathan ULg et al

in PLoS ONE (2013), 8(2),

The use of a UAS (Unmanned Aircraft System) was tested to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing ×100™ equipped with a Ricoh GR III camera was used to ... [more ▼]

The use of a UAS (Unmanned Aircraft System) was tested to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing ×100™ equipped with a Ricoh GR III camera was used to test animal reaction as the UAS passed, and visibility on the images. No reaction was recorded as the UAS passed at a height of 100 m. Observations, made on a set of more than 7000 images, revealed that only elephants (Loxodonta africana) were easily visible while medium and small sized mammals were not. The easy observation of elephants allows experts to enumerate them on images acquired at a height of 100 m. We, therefore, implemented an aerial strip sample count along transects used for the annual wildlife foot count. A total of 34 elephants were recorded on 4 transects, each overflown twice. The elephant density was estimated at 2.47 elephants/km2 with a coefficient of variation (CV%) of 36.10%. The main drawback of our UAS was its low autonomy (45 min). Increased endurance of small UAS is required to replace manned aircraft survey of large areas (about 1000 km of transect per day vs 40 km for our UAS). The monitoring strategy should be adapted according to the sampling plan. Also, the UAS is as expensive as a second-hand light aircraft. However the logistic and flight implementation are easier, the running costs are lower and its use is safer. Technological evolution will make civil UAS more efficient, allowing them to compete with light aircraft for aerial wildlife surveys. [less ▲]

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See detailModeling recent bark stripping by red deer (Cervus elaphus) in South Belgium coniferous stands
Ligot, Gauthier ULg; Gheysen, Thibaut; Lehaire, François ULg et al

in Annals of Forest Science : a Multidisciplinary and International Journal (2013), 70(3),

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