References of "Bogaert, Jan"
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See detailSeeing Central African forests through their largest trees
Bastin, Jean-François ULg; Barbier, Nicolas; Réjou-Méchain, Maxime et al

in Scientific Reports (2015)

Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which ... [more ▼]

Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies. [less ▲]

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See detailAnatomic features underlying wood density, in 110 rainforest tree species from central Congo basin
de Haulleville, Thalès ULg; Rousseau, Mélissa; Morin-Rivat, Julie ULg et al

Poster (2015, May)

Investigate the influence of fiber thickness and vessel diameter on the wood density in 110 rainforest tree species, and the relationships between wood density, wood water content and shrinking ratio.

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See detailLes vers à soie sauvages à Madagascar : Enjeux écologiques et socio-économiques
Verheggen, François ULg; Haubruge, Eric ULg; Bogaert, Jan ULg

in Entomologie Faunistique = Faunistic Entomology (2015), 68

We here introduce the book « The Malagasy silk moths: ecological and socio-economic challenges » published in 2013 by the Presses agronomiques de Gembloux (Belgium). This book reflects the achievements ... [more ▼]

We here introduce the book « The Malagasy silk moths: ecological and socio-economic challenges » published in 2013 by the Presses agronomiques de Gembloux (Belgium). This book reflects the achievements and scientific activities of the project "Sustainable Management and valorisation of the endemic silkworm Borocera cajani in forest areas in the Antananarivo region" funded by Commission universitaire pour le Développement (CUD - CIUF). [less ▲]

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See detailOptimization of a cheap and residential small-scale production of edible crickets with local by-products as an alternative protein-rich human food source in Ratanakiri Province (Cambodia)
Caparros Megido, Rudy ULg; Alabi, Taofic ULg; Nieus, Clément et al

in Journal of the Science of Food and Agriculture (2015)

Background - Health status of the indigenous people of the Ratanakiri Province, Cambodia, is significantly lower compared to the rest of the nation. The domestication and mass production of insects may ... [more ▼]

Background - Health status of the indigenous people of the Ratanakiri Province, Cambodia, is significantly lower compared to the rest of the nation. The domestication and mass production of insects may represent a sustainable, cost effective and high quality alternative source of protein to traditional livestock. This study aimed to optimise a cheap and residential cricket breeding system based on unused wild resources. The cricket development, Teleogryllus testaceus (Walker), under seven diets composed of taro aerial parts, young cassava leaves, young cashew leaves and brown rice flour (with or without banana slices), versus a traditionally used broiler feed diet was studied. Results - Cricket mortality was low in all diets, except the two cashew-based diets. Total biomass was significantly higher under the broiler feed, in addition to the two diets containing a combination of cassava leaf powder and brown rice. Yet, crickets fed with the taro diet had the highest percentage of protein. Concerning the breeding system cost, units using cassava leaves were the cheapest ones. Conclusion – Diets based of cassava leaves seems to be the most promising ones. Nevertheless, to produce crickets with a high body mass and a high protein level, a new experiment must be realised in which the cassava leaf maturity will be adapted to fit with the cricket growth stage. Moreover, to reduce the cost of the breeding units, handmade local products should be used instead of purchased components. [less ▲]

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See detailTermite mound identification through aerial photographic interpretation in Lubumbashi , Democratic Republic of the Congo : methodology evaluation
Vranken, Isabelle ULg; Adam, Marielle; Mujinya Baziraké, Basile et al

in Tropical Conservation Science (2014), 7(4), 733-746

Les termites des régions tropicales sont d’une importance critique pour le fonctionnement et les services écosystémiques dans les régions de forêt claire et de savane. Les termitières peuvent également ... [more ▼]

Les termites des régions tropicales sont d’une importance critique pour le fonctionnement et les services écosystémiques dans les régions de forêt claire et de savane. Les termitières peuvent également être utilisées comme engrais et bio-indicateurs de perturbations anthropiques telles que l’agriculture ou la production de charbon. La télédétection peut contribuer à identifier et caractériser la densité et la distribution des termitières à moindres frais. Afin de tester son efficacité, les termitières ont été identifiées sur le terrain et comparées avec les résultats d’interprétation de photographies aériennes Google Earth en libre accès. Cette comparaison a été appliquée sur 17 sites dans l’hinterland de la ville minière de Lubumbashi, Katanga, République Démocratique du Congo, confrontée à une croissance élevée de population, à l’insécurité alimentaire ainsi que d’intenses fragmentation et dégradation de la couverture originelle de forêt claire (Miombo). Les influences de la hauteur et du diamètre des termitières ainsi que de la période d’acquisition de l’image (année et saison) ont été testées statistiquement. Le nombre de termitières observées sur le terrain est généralement surestimé sur l’image. La hauteur et la saison des pluies en favorisent l’identification correcte, tandis que la distribution spatiale n’est pas significativement influencée par les erreurs d’identification. Un modèle correctif a été défini et sa pertinence statistiquement vérifiée. L’identification des termitières via Google Earth s’avère efficace tant que la position précise de chaque termitière n’est pas requise. Cette approche constitue une réduction considérable des coûts de missions de terrain liées aux études sur les termitières. [less ▲]

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See detailAboveground biomass mapping of African forest mosaics using canopy texture analysis: toward a regional approach.
Bastin, Jean-François ULg; Barbier, Nicolas; Couteron, Pierre et al

in Ecological Applications (2014), 24(8), 1984-2001

In the context of the reduction of greenhouse gas emissions caused by deforestation and forest degradation (the REDD+ program), optical very high resolution (VHR) satellite images provide an opportunity ... [more ▼]

In the context of the reduction of greenhouse gas emissions caused by deforestation and forest degradation (the REDD+ program), optical very high resolution (VHR) satellite images provide an opportunity to characterize forest canopy structure and to quantify aboveground biomass (AGB) at less expense than methods based on airborne remote sensing data. Among the methods for processing these VHR images, Fourier textural ordination (FOTO) presents a good potential to detect forest canopy structural heterogeneity and therefore to predict AGB variations. Notably, the method does not saturate at intermediate AGB values as do pixelwise processing of available space borne optical and radar signals. However, a regional scale application requires to overcome two difficulties: (i) instrumental effects due to variations in sun-scene-sensor geometry or sensor-specific responses that preclude the use of wide arrays of images acquired under heterogeneous conditions and (ii) forest structural diversity including monodominant or open canopy forests, which are of particular importance in Central Africa. In this study, we demonstrate the feasibility of a rigorous regional study of canopy texture by harmonizing FOTO indices of images acquired from two different sensors (Geoeye-1 and QuickBird-2) and different sun-scene-sensor geometries and by calibrating a piecewise biomass inversion model using 26 inventory plots (1 ha) sampled across very heterogeneous forest types. A good agreement was found between observed and predicted AGB (RSE=15%; R²=0.85; p-value<0.001) across a wide range of AGB levels from 26 Mg/ha to 460 Mg/ha, and was confirmed by cross validation. A high-resolution biomass map (100 m pixels) was produced for a 400 km² area, and predictions obtained from both imagery sources were consistent with each other (r=0.86; slope=1.03; intercept=12.01 Mg/ha). These results highlight the horizontal structure of forest canopy as a powerful descriptor of the entire forest stand structure and heterogeneity. In particular, we show that quantitative metrics resulting from such textural analysis offer new opportunities to characterize the spatial and temporal variation of the structure of dense forests and may complement the toolbox used by tropical forest ecologists, managers or REDD+ national monitoring, reporting and verification bodies. [less ▲]

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See detailDeuxième mission de terrain dans la reserve de Yangambi
de Haulleville, Thalès ULg; Bogaert, Jan ULg; Beeckman, Hans

Scientific conference (2014, March 18)

Presentation of Thales de Haulleville's planned fieldwork during his second field mission.

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See detailVers une synthèse de la conception et une définition des zones dans le gradient urbain-rural
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(1), 61-74

The increasing footprint of urbanization on landscapes justifies the study of cities and the zones surrounding them. Paradoxically, the concepts relating to these zones remain unclear. Scientists from ... [more ▼]

The increasing footprint of urbanization on landscapes justifies the study of cities and the zones surrounding them. Paradoxically, the concepts relating to these zones remain unclear. Scientists from different disciplines diverge when defining these zones or their limits; they even often mention the zones without any definition. This practice excludes comparison between studies. By means of bibliographic research, the variety of terms used to describe the different zones composing the urban-rural gradient has been evidenced, as well as the characteristics of the zones themselves. They have been evaluated according to their relative importance and according to a series of criteria. Finally, new definitions for the different zones have been proposed in order to enable their identification in the field. [less ▲]

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See detailA diachronic analysis of the dynamic of two cities: Kisangani and Lubumbashi (Democratic Republic of Congo): How do the extension and/or of the densification of these cities impact the urban internal and peripheral ecosystems?
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

Poster (2014, February 07)

The dynamics of two cities between two years (2002 and 2010 for Kisangani; 2002 and 2008 for Lubumbashi, both part of the Democratic Republic of Congo) have been examined in order to estimate how their ... [more ▼]

The dynamics of two cities between two years (2002 and 2010 for Kisangani; 2002 and 2008 for Lubumbashi, both part of the Democratic Republic of Congo) have been examined in order to estimate how their extension and/or of the densification have impacted the urban internal and peripheral ecosystems. This study singularizes itself from the subjective ones by its quantified and objective approach based on landscape ecology. This discipline assumes that the landscape pattern description is important because, according to its central hypothesis called “pattern-process paradigm”, the ecological processes influence landscape structure and vice versa. Composition metrics, which are commonly used in landscape ecology, describe the pattern among other things in quantifying the presence and the number of patches from the various classes within the landscape. For each city two SPOT 5 images were classified with a oriented-object supervised approach; then built area proportion index, a composition landscape metric, has been evaluated in order to 1) identify the extent of each area (urban, suburban, rural) within the urban-rural gradient, 2) quantify the dynamic of the different areas in the urban-rural gradient during the last decade and 3) quantify the effect of a decade of urban and suburban growth on ecosystems. The similarities and differences between these cities, relevance and gaps in the method have then been identified and discussed. [less ▲]

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See detailSpatial patterns and morphology of termite (Macrotermes falciger) mounds in the Upper Katanga, D.R. Congo
Mujinjya, Baile Baziraké; Adam, Marielle; Mees, Florias et al

in Catena (2014), 114

This study examines the spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds in the peri-urban zone of Lubumbashi, D.R. Congo. Spatial patterns of mounds were ... [more ▼]

This study examines the spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds in the peri-urban zone of Lubumbashi, D.R. Congo. Spatial patterns of mounds were assessed using high-resolution satellite images for 24 plots of variable size (3 to 27 ha). Soil morphological features were described for five termite-mound profiles of 5 to 9 m depth/height. A mean areal number density of 2.9 ± 0.4 mounds ha−1 is estimated for the degraded miombo woodland of the study area. Spatial statistical analyses document that termite mounds are regularly distributed in all studied plots. The overall mean nearest-neighbour distance between termite mounds is 44.6 ± 0.6 m. The high relative number of inactive mounds in the region, with regular distribution patterns, suggests that current termite mound occurrences are largely relict features.There are no clear indications for an impact of the nature of the parent material on the spatial distribution of the mounds. One aspect of differences in morphology between the studied mounds is that the stone layer occurs at greater depth in topographic low areas than at crest and slope positions. This is interpreted as being mainlyconditionedbyerosion.Mn–Fe oxideconcentrationsoccurringinallstudiedtermite moundprofiles reflect a seasonally high perched water table beneath the mound, which is more pronounced at lower landscape positions. In summary, mound positions in the habitat are consistent with intraspecific competition rather than soil and substrate characteristics as controlling factor, whereas variation in morphological characteristics between termite-mound profiles appears to be a function of the parent material [less ▲]

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See detailA review on the use of entropy in landscape ecology: heterogeneity, unpredictability, scale dependence and their links with thermodynamics
Vranken, Isabelle ULg; Baudry, Jacques; Aubinet, Marc ULg et al

in Landscape Ecology (2014)

The identification of a universal law that can predict the spatiotemporal structure of any entity at any scale has long been pursued. Thermodynamics have targeted this goal, and the concept of entropy has ... [more ▼]

The identification of a universal law that can predict the spatiotemporal structure of any entity at any scale has long been pursued. Thermodynamics have targeted this goal, and the concept of entropy has been widely applied for various disciplines and purposes, including landscape ecology. Within this discipline, however, the uses of the entropy concept and its underlying assumptions are various and are seldom described explicitly. In addition, the link between this concept and thermodynamics is unclear. The aim of this paper is to review the various interpretations and applications of entropy in landscape ecology and to sort them into clearly defined categories. First, a retrospective study of the concept genesis from thermodynamics to landscape ecology was conducted. Then, 50 landscape ecology papers that use or discuss entropy were surveyed and classified by keywords, variables and metrics identified as related to entropy. In particular, the thermodynamic component of entropy in landscape ecology and its various interpretations related to landscape structure and dynamics were considered. From the survey results, three major definitions (i.e., spatial heterogeneity, the unpredictability of pattern dynamics and pattern scale dependence) associated with the entropy concept in landscape ecology were identified. The thermodynamic interpretations of these definitions are based on different theories. The thermodynamic interpretation of spatial heterogeneity is not considered relevant. The thermodynamic interpretation related to scale dependence is also questioned by complexity theory. Only unpredictability can be thermodynamically relevant if appropriate measurements are used to test it. [less ▲]

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See detailBiocultural landscapes. Diversity, functions and values
Hong, SK; Bogaert, Jan ULg; Min, Q

Book published by Springer (2014)

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See detailAnthropogenic effects in landscapes: Historical context and spatial pattern
Bogaert, Jan ULg; Vranken, Isabelle ULg; Andre, Marie ULg

in Hong, S.-K.; Bogaert, Jan; Min, Q. (Eds.) Biocultural Landscapes: Diversity, Functions and Values (2014)

Bio-cultural landscapes are characterized by anthropogenic pattern features, of which the measurement constitutes a key step in landscape analysis. Metrics and strategies for this measurement of ... [more ▼]

Bio-cultural landscapes are characterized by anthropogenic pattern features, of which the measurement constitutes a key step in landscape analysis. Metrics and strategies for this measurement of anthropogenic patterns and their dynamics are discussed, considering the pattern/process paradigm, the patch-corridor- matrix model and the complementarity of landscape composition and configuration as conceptual benchmarks. Historically, noticeable anthropogenic effects are accepted to have appeared in landscapes after the invention of agriculture and further trends of landscape change could be linked to the development of agriculture. Through time, a sequence of landscape dynamics with three stages is expected, in which a natural landscape matrix is initially substituted by an agricultural one; urban patch types will later on dominate the matrix as a consequence of ongoing urbanization. The importance of the development of agriculture and its productivity for the evolution of settlements, villages and cities is emphasized. Anthropogenic change of landscapes confirms the status of geographical space as a limited resource. [less ▲]

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See detailObituary Ivan Impens (1935-2014). Poor is the disciple who does not surpass his master
Bogaert, Jan ULg; Nijs, I; Ceulemans, R

in Tropicultura (2014), 32(1), 110-111

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See detailLe patron urbain, un facteur influençant l'impact de l'urbanisation sur les écosystèmes: les cas de Kisangani et de Lubumbashi (RDC)
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

in PACODEL (Ed.) Colloque international Territoires périurbains: développement, enjeux et perspectives dans les pays du sud (2013, December 19)

Les dynamiques et patrons paysagers de deux villes entre deux années (Kisangani entre 2002 et 2010 ; Lubumbashi entre 2002 et 2008, en République Démocratique du Congo) ont été étudiés afin d’évaluer leur ... [more ▼]

Les dynamiques et patrons paysagers de deux villes entre deux années (Kisangani entre 2002 et 2010 ; Lubumbashi entre 2002 et 2008, en République Démocratique du Congo) ont été étudiés afin d’évaluer leur influence sur l’impact de l’extension et/ou densification de ces villes, et plus particulièrement de leur zone périurbaine, sur leurs écosystèmes internes et périphériques. En effet, le patron paysager occupe une place fondamentale dans l’hypothèse centrale de l’écologie du paysage, appelée pattern-process paradigm puisqu’il influence les processus écologiques et inversement. Sa description et son analyse sont donc particulièrement importantes (Bogaert et al. 2004; Coulson et al. 1999). Les indices de composition, communément utilisés en écologie du paysage, décrivent entre autres le patron en quantifiant la présence et le nombre de taches issues des différentes classes du paysage (Alberti 2008). D’autre part, les villes ne cessant d'augmenter leur emprise sur les paysages dont elles font partie, l'étude des espaces qui les ceinturent, le phénomène de leur extension dans les régions rurales ainsi que les schémas conceptuels de leur morphologie et dynamique interne sont plus que jamais des sujets d'actualité (Bhatta et al., 2010; Borsdorf et al., 2002; De Blij, 1977; Gaston, 2010; Halleux, 2006). Paradoxalement, les scientifiques de différentes disciplines peinent à donner une définition, des caractéristiques et des limites acceptées par tous aux notions se rattachant aux différentes zones présentes dans le gradient urbain-rural. Cette étude se distingue des autres, généralement subjectives, par son approche quantifiée et objective. Pour chacune des deux villes, deux images SPOT 5 ont été classifiées sur base d’une approche orientée-objet (Definiens 2013). Ensuite, des indices de composition paysagère ont été évalués afin 1) d’identifier l’étendue de chaque zone (urbaine, périurbaine, rurale) au sein du gradient urbain-rural en utilisant les définitions de zones proposées par André et al. (sous presse), 2) de décrire ces différentes zones en quantifiant les caractéristiques morphologiques les plus couramment citées avant d’en borner les valeurs (André et al. 2012) et 3) de quantifier la dynamique des différentes zones au cours de la dernière décade. Ensuite, les similarités et différences entre ces villes ainsi que la pertinence et les faiblesses de la méthode ont été identifiées et discutées. Les résultats de cette étude ont pour ambition de contribuer à une meilleure compréhension et prise en compte du rôle du patron paysager dans la résistance potentielle des écosystèmes naturels à l’extension et/ou la densification d’une ville donnée. [less ▲]

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