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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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See detailTous créatifs! Art et Science 2.0: Les scientifiques et l'art
Andre, Marie ULg; Leleux, Violaine ULg; Bogaert, Jan ULg

Conference (2013, October 08)

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See detailCity pattern as a factor influencing the impact of urbanization on ecosystems - A diachronic analysis of the dynamic of two cities: Kisangani and Lubumbashi (Democratic Republic of Congo)
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

Conference (2013, September 06)

The patterns and 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 ... [more ▼]

The patterns and 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 they influence the impact of extension and/or of densification on urban internal and peripheral ecosystems. For each city two SPOT 5 images were classified with a oriented-object supervised approach; then composition landscape metrics (built area proportion index, anthropized surface proportion index, equitability index of area proportion of classes, dominant class index, dominant class proportion index) have been evaluated in order to 1) identify the extend of each area (urban, suburban, rural) within the urban-rural gradient, 2) quantify the most commonly cited morphological characteristics to describe these different areas and 3) quantify the dynamic of the different areas during this decade. Landscape ecology assumes that the landscape pattern description is important because, according to the 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. This study singularizes itself from the subjective ones by its quantified and objective approach. The similarities and differences between these cities, relevance and gaps in the method have then been identified and discussed. The results of this study are aimed to be used by urban planners for the evaluation of the potential resistance of internal and peripheral natural ecosystems to the extension and/or the densification of a given city, taking into account its pattern and dynamic. It might help them in their choice between different planning alternatives. [less ▲]

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See detailCity pattern as a factor influencing the impact of urbanization on ecosystems - A diachronic analysis of the dynamic of two cities: Kisangani and Lubumbashi (Democratic Republic of Congo)
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

in Nunes Silva, Carlos (Ed.) Colonial and postcolonial urban planning in Africa (2013, September 06)

The patterns and 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 ... [more ▼]

The patterns and 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 they influence the impact of extension and/or of densification on urban internal and peripheral ecosystems. For each city two SPOT 5 images were classified with a oriented-object supervised approach; then composition landscape metrics (built area proportion index, anthropized surface proportion index, equitability index of area proportion of classes, dominant class index, dominant class proportion index) have been evaluated in order to 1) identify the extend of each area (urban, suburban, rural) within the urban-rural gradient, 2) quantify the most commonly cited morphological characteristics to describe these different areas and 3) quantify the dynamic of the different areas during this decade. Landscape ecology assumes that the landscape pattern description is important because, according to the 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. This study singularizes itself from the subjective ones by its quantified and objective approach. The similarities and differences between these cities, relevance and gaps in the method have then been identified and discussed. The results of this study are aimed to be used by urban planners for the evaluation of the potential resistance of internal and peripheral natural ecosystems to the extension and/or the densification of a given city, taking into account its pattern and dynamic. It might help them in their choice between different planning alternatives. [less ▲]

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

Book published by Presses agronomiques de Gembloux (2013)

Cet ouvrage reflète les réalisations et activités scientifiques du projet de coopération universitaire « Gestion et valorisation durable du ver à soie endémique Borocera cajani en milieu forestier dans la ... [more ▼]

Cet ouvrage reflète les réalisations et activités scientifiques du projet de coopération universitaire « Gestion et valorisation durable du ver à soie endémique Borocera cajani en milieu forestier dans la région d’Antananarivo » financé par la Commission Universitaire pour le Développement (CUD). Ce projet de recherche est le fruit d’une collaboration étroite entre le Département des Eaux et Forêts de l’école Supérieure des Sciences Agronomiques de l’Université d’Antananarivo, l’Université de Liège et l’Université Libre de Bruxelles. Une première section de l’ouvrage porte sur les aspects biologiques et écologiques des vers à soie endémiques de Madagascar – avec l’accent sur le landibe (Borocera cajani) – notamment sa morphologie, l’estimation de son abondance dans l’aire étudiée, la dynamique de ses populations, ses interactions avec ses plantes hôtes, son comportement d’alimentation et son développement larvaire. La deuxième section étudie les dimensions écologiques et botaniques de l’habitat des vers à soie, à savoir les formations de tapia (Uapaca bojeri), principalement à travers les aspects sylvicoles et botaniques, les causes et indicateurs de dégradation, la discussion autour de sa dénomination, la diversité floristique, la régénération et l’inventaire des ressources sauvages comestibles et leurs caractéristiques chimiques. La troisième section renseigne sur l’état et la valorisation de la filière soie et couvre une diversité d’approches, allant des connaissances et savoir-faire des communautés locales au rôle de la soie dans l’économie rurale. Le contexte socio-institutionnel ainsi que les interactions entre les acteurs concernés par la filière complètent ce volet. L’ouvrage contient 21 contributions scientifiques, rédigées par 34 auteurs, dont certains ont déjà fait l’objet d’une publication dans une revue internationale. Le volume a été composé sous la direction scientifique de François J. Verheggen, Jan Bogaert et éric Haubruge, enseignants à Gembloux Agro-Bio Tech (Université de Liège). Il s’adresse à tous ceux qui s’intéressent à la coopération universitaire et/ou aux recherches écologiques, entomologiques et sociologiques dans un contexte malgache. [less ▲]

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See detailConventional tree height-diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin
Kearsley, E; de Haulleville, Thalès ULg; Hufkens, K et al

in Nature Communications (2013), 4

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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 detailAbove-ground biomass and structure of 260 african tropical forests
Lewis, Simon L.; Sonké, Bonaventure; Sunderland, Terry et al

in Philosophical Transactions of the Royal Society B (2013), 368

We report above-ground biomass (AGB), basal area, stemdensity and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries ... [more ▼]

We report above-ground biomass (AGB), basal area, stemdensity and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha21 (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha21) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- comparedwithneotropical forests.However, mean stem density is low(426+11 stems ha21 greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three months of the year; a negative relationship with temperature; positive relationship with clay-rich soils; and negative relationshipswith C :Nratio (suggesting a positive soil phosphorus–AGB relationship), and soil fertility computed as the sum of base cations. The results indicate that AGB is mediated by both climate and soils, and suggest that the AGB of African closed-canopy tropical forests may be particularly sensitive to future precipitation and temperature changes. [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 detailInvestigation of edge effect on wood density in recent tropical forest edges in Yangambi Man and Biosphere Reserve
de Haulleville, Thalès ULg; Bogaert, Jan ULg; Beeckman, Hans

Conference (2013, April)

Rapid development of lumbering activities in tropical forested areas has an important impact on carbon stocks and landscape configuration. Indeed, lumbering tend to fragment forest patches, extend edges ... [more ▼]

Rapid development of lumbering activities in tropical forested areas has an important impact on carbon stocks and landscape configuration. Indeed, lumbering tend to fragment forest patches, extend edges length, and expose core areas to non-forested ecosystems. These exposed core areas then undergo new constraints that can lead to a shift in their ecological features, called the edge effect. We investigate the possible presence of an edge effect on wood density in Yangambi reserve. Wood density (along with diameter and height) is a key feature for biomass estimations in tropical forests. Thus, fluctuations of wood density in forest edges could lead to incorrect estimations of carbon stocks. Ten 1ha plots were installed in core and recent (5 to 10 years) forest¿s edges. Trees were measured and wood samples were collected for density analysis. We focused on 2 main research questions: 1) Does the edge effect induce the emergence of species with a higher or lower wood density in edge area? 2) Does wood density differ amongst individuals of the same specie in core and in edge area? While the data is still being explored as we write, preliminary results seem to indicate that there is no significant difference between the overall mean wood density in edge and core plots. Density differences amongst species are still under exploration. If this behaviour still holds, this would imply that the fragmentation of a forested landscape has no short-term effect on the overall forest wood density and thus, no effect on biomass estimations. [less ▲]

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See detailEffets de lisière sur la productivité du teck (Tectona grandis L.f.): étude de cas des teckeraies privées du Sud-Bénin
Toyi, Mireille Scholastique; Bastin, Jean-François ULg; Andre, Marie ULg et al

in Tropicultura (2013), 31(1), 62-70

The present study aims to improve the production of teak wood (Tectona grandis L.f.) in private plantations in southern Benin through the application of a central concept in landscape ecology: the edge ... [more ▼]

The present study aims to improve the production of teak wood (Tectona grandis L.f.) in private plantations in southern Benin through the application of a central concept in landscape ecology: the edge effect. As teak is an heliophilous species, the hypothesis of a higher wood production in edges was tested on the basis of the basal area. Sixty-two private teak plantations were investigated and 10,667 trees were measured. The stratified sampling scheme in three distinct parts for each plantation (the centre, the edge and the summits) permitted to highlight the edge effect on wood production. For each part, a plot was installed and the diameter at breast height (dbh) was measured for all trees. The leaf area between the edge and the centre of plantations was measured. Finally, the influence of the spatial configuration of plantations and the direction of each side of these plantations on the production of wood was tested. Results show that the edge effect on the production of teak wood affects four planting lines, the first presenting a production of 150% relative to the centre. We noticed a significant influence of the edge on the leaf area of about 218% relative to the centre. No influence of the direction of the sides of the plantation was observed. The shape of the plantations presents a significant influence on the wood production. These results permitted to propose a planting model included in an agroforestry system that optimizes the production of wood per area and having a succession of two planting lines interrupted by fields. [less ▲]

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