Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailThe ecological study of an unknown non-timber forest product (NTFP) : The African walnut (Coula edulis Baill.)
Moupela, Christian; Vermeulen, Cédric ULg; Brostaux, Yves ULg et al

Conference (2011, November)

Le noisetier d’Afrique, Coula edulis Bail., produit des graines de grande valeur nutritive régulièrement collectées et commercialisées par les populations locales. Toutefois, certains aspects fondamentaux ... [more ▼]

Le noisetier d’Afrique, Coula edulis Bail., produit des graines de grande valeur nutritive régulièrement collectées et commercialisées par les populations locales. Toutefois, certains aspects fondamentaux de son écologie, dont le potentiel de production et la prédation des fruits, demeurent inconnus, ce qui peut constituer un frein à sa valorisation. L’étude s’est déroulée au Gabon et s’est attachée à quantifier la production fruitière de l’espèce et à identifier les prédateurs potentiels des fruits. Trente-neuf collecteurs circulaires ont été installés sous les houppiers, les données récoltées (nombre et masse des fruits) étant ensuite mises en relation avec le diamètre. Par ailleurs, sept semenciers ont fait l’objet d’observations indirectes grâce à un dispositif de caméras-pièges. Le diamètre minimum de fertilité est de 12,3 cm, tandis que 23 cm dhp constitue pour l’espèce le diamètre effectif de fructification. Celle-ci se produit de décembre à avril. Les quantités de fruits sont corrélées positivement au diamètre. Dix espèces animales ont été observées aux pieds des arbres en fruits, leur rôle dans la dynamique de l’espèce est potentiellement important. [less ▲]

Detailed reference viewed: 45 (20 ULg)
Full Text
Peer Reviewed
See detailAn ecological study of Electra posidoniae Gautier, 1954 (Cheilostomata, Anasca), a bryozoan epiphyte solely found on the seagrass Posidonia oceanica (L.) Delile, 1813
Lepoint, Gilles ULg; Mouchette, Olivier; Pelaprat, Corine et al

in Belgian Journal of Zoology (2014), 144(1), 51-63

The bryozoan Electra posidoniae Gautier is found solely on the leaves of the Neptune grass Posidonia oceanica (L.) Delile, dominating the leaf epifauna of this seagrass. Epiphytes of marine angiosperms ... [more ▼]

The bryozoan Electra posidoniae Gautier is found solely on the leaves of the Neptune grass Posidonia oceanica (L.) Delile, dominating the leaf epifauna of this seagrass. Epiphytes of marine angiosperms (or seagrasses) often play an important role in ecosystem functioning, for example as food web suppliers. As dysfunction of epiphytic compartment is often implied in human-induced seagrass decline, it is important to understand the dynamics and life traits of this community in pristine areas. This study involved the monthly assessment of colonization dynamics, biomass seasonality and diet composition through stable isotopes measurements of E. posidoniae at a depth of 10 m in the Revellata Bay (Corsica, Mediterranean Sea). Ancestrulae (i.e. colony founders) appeared towards the end of winter and were very selective in their settlement position along the P. oceanica leaves. A maximum of 100,000 colonies per square meter was recorded. E. posidoniae colonies dominated the epiphytic community biomass in early spring, and were over-covered by epiphytic algae in June. Food shortage could be also involved in this decrease. Although stable isotope ratios of C, N and S showed that this suspension feeder mainly relies on the water column productivity for its food, other food sources such as re-suspended epiphytic diatoms could be important in late spring (i.e. after the phytoplanktonic bloom). Additionally, a contribution of seagrass phytodetritus to the diet of this species cannot be excluded. The species was almost absent in winter, raising the question of its recruitment in spring. This study confirms the quantitative importance of this species in the seagrass meadow and explores its role in the relationship between the water column and this seagrass ecosystem. [less ▲]

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailEcological thresholds and estimates of breaking points in newt populations: a useful tool to categorise habitat use and apply conservation measures
Denoël, Mathieu ULg; Ficetola, Gentile

Poster (2007)

Ecological thresholds are defined as points at which a rapid change occurs from one ecological condition to another. Their determination in species–habitat relationships has important implications because ... [more ▼]

Ecological thresholds are defined as points at which a rapid change occurs from one ecological condition to another. Their determination in species–habitat relationships has important implications because they allow to understand ecological requirements of species and to provide efficient conservation measures. However, there is a lack of concordance across studies and this method was not yet applied to newts. In this study, we sampled 371 ponds to gather occurrence data on the palmate newt Triturus heveticus and the Alpine newt Triturus alpestris. We tested for the existence of significant thresholds for three variables: distance to forest, forest and crop covers. We found significant thresholds for both landscape configuration and composition, with relationships between distance to forest and occurrence of Triturus alpestris and T. helveticus, and forest and crop cover and T. helveticus. Both species require breeding ponds within a given distance from the forest, but T. helveticus is more dependent on forest availability than T. alpestris: its ecological threshold is located at lower distance from forest edge, and requires also higher values of forest cover. Crops have a negative influence on palmate newt distribution with a significant breaking point, but not for T. alpestris in the studied area. These results indicate that thresholds can be a useful concept from which tools may be developed. They are particularly pertinent to focus conservation effort for threatened species and their habitats as quantitative measures of the most required habitats for species can be obtained from statistically determined breaking points [less ▲]

Detailed reference viewed: 22 (3 ULg)
Full Text
Peer Reviewed
See detailEcological thresholds: an assessment of methods to identify abrupt changes in species-habitat relationships
Ficetola, Gentile Francesco; Denoël, Mathieu ULg

in Ecography (2009), 32(6), 1075-1084

Habitat thresholds are usually defined as "points of abrupt change" in the species–habitat relationships. Habitat thresholds can be a key tool for understanding species requirements, and provide an ... [more ▼]

Habitat thresholds are usually defined as "points of abrupt change" in the species–habitat relationships. Habitat thresholds can be a key tool for understanding species requirements, and provide an objective definition of conservation targets, by identifying when habitat loss leads to a rapid loss of species, and the minimum amount of habitat necessary for species persistence. However, a large variety of statistical methods have been used to analyse them. In this context, we reviewed these methods and, using simulated data sets, we tested the main models to compare their performance on the identification of thresholds. We show that researchers use very different analytical tools, corresponding to different operational definitions of habitat thresholds, which can considerably affect their detection. Piecewise regression and generalized additive models allow both the distinction between linear and nonlinear dynamics, and the correct identification of break point position. In contrast, other methods such as logistic regression fail because they may incorrectly detect thresholds in gradual patterns, or they may over or underestimate the threshold position. In conservation or habitat modelling, it is important to focus efforts efficiently and the inappropriate choice of statistical methods may have detrimental consequences. [less ▲]

Detailed reference viewed: 93 (14 ULg)
Full Text
Peer Reviewed
See detailThe ecological validity of traditional memory evaluation in relation with controlled memory processes and routinization
Dubreuil, P.; Adam, Stéphane ULg; Bier, N. et al

in Archives of Clinical Neuropsychology (2007), 22(8), 979-989

The neuropsychological evaluation of memory by traditional tests raises questions about their ecological validity, as the results on these tests often have little relation to the memory complaints. In an ... [more ▼]

The neuropsychological evaluation of memory by traditional tests raises questions about their ecological validity, as the results on these tests often have little relation to the memory complaints. In an attempt to explain this lack of relationship, the present study had two objectives: (1) explore the ecological superiority of the Process Dissociation Procedure (PDP) over traditional memory tests and (2) explore the effects of routinization on the relationship between memory complaints and memory tests. Thirty-three participants aged 55-86 years were given the PDP (memory evaluation), two questionnaires evaluating daily memory complaints (QAM and CDS) and a questionnaire evaluating routinization (EPR). The results indicate that the PDP, with its measure of controlled processes, is more ecological than traditional memory tests for elderly people. As well, the participants' lifestyle (routinized versus non-routinized) influenced their results on memory tests. The results are discussed in relation to neuropsychological evaluation and rehabilitation. (C) 2007 National Academy of Neuropsychology. Published by Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 27 (1 ULg)
Full Text
See detailEcological wood anatomy of 155 African tropical hardwoods
Beeckman, Hans; Fayolle, Adeline ULg; Doucet, Jean-Louis ULg et al

Conference (2013, April 19)

In this study we aimed at identifying the anatomical characters expressing life history traits of woody species from the northern Congo Basin. We crosschecked three databases: the botanical inventories ... [more ▼]

In this study we aimed at identifying the anatomical characters expressing life history traits of woody species from the northern Congo Basin. We crosschecked three databases: the botanical inventories produced during the CoForChange project (857 spp.), the database of life history traits established by the CIRAD (France) and GxABT (Belgium) (464 spp.), and the anatomical database Inside Wood (761 spp. and genera for tropical Africa). A total of 155 shared species was obtained. We performed correspondence analyses between the anatomical characters and two main groups of traits: leaf phenology and light-requirement. Results showed: (i) that wood anatomy is involved in leaf phenology and light-requirement in a significant way (7.56% of the variance on axe1), (ii) that evergreenness was correlated to IAWA characters 14 to 18 (scalariform perforation plates, e.g. Olacaceae) and deciduousness to characters 118 to 122 (storied structures, e.g. Malvaceae and Meliaceae), (iii) that pioneer (P) and non-pioneer light-demanding (NPLD) species showed similar traits but were different from shade-tolerant (ST) species, (iv) that deciduous and evergreen species showed separate distributions, and (v) that wood anatomy validated the well documented strong correlation between evergreen species and ST species, with an inversion of the tendency for deciduous species correlated to P and NPLD species. We conclude that anatomical characters can be used as indicators of life history traits in species-rich biomes. Further investigations are needed to increase the input of wood anatomy in explaining the life history traits in African tropical species. [less ▲]

Detailed reference viewed: 188 (20 ULg)
Full Text
Peer Reviewed
See detailEcological, morphological and allozymic differentiation between diploid and tetraploid knapweeds (Centaurea jacea) from a contact zone in the Belgian Ardennes
Hardy, O. J.; Vanderhoeven, SONIA ULg; De Loose, M. et al

in New Phytologist (2000), 146(2), 281-290

In the northeastern part of Belgium, the Centaurea jacea complex shows extensive morphological variation and is represented by a diploid (2n = 22) and a tetraploid (2n = 44) cytotype. Polysomic ... [more ▼]

In the northeastern part of Belgium, the Centaurea jacea complex shows extensive morphological variation and is represented by a diploid (2n = 22) and a tetraploid (2n = 44) cytotype. Polysomic inheritance of allozyme markers in the tetraploids, suggesting autopolyploidy, is here demonstrated for the first time. In order to test whether the tno cytotypes occupy distinct habitats and possess different gene pools, patterns of allozymic and morphological variation were investigated in relation to ploidy level and site characteristics in 26 populations from the Belgian Ardennes. The two cytotypes showed a parapatric distribution, the diploids occurring at higher elevations (mostly above 500 m) than the tetraploids (mostly below 500 m). Three mixed populations were found near the contact zone of the two cytotypes. Within the mixed populations no triploid plant and no evidence for gene flow between cytotypes were found, despite widely overlapping flowering periods. The two cytotypes can be distinguished on the basis of morphological traits and enzymatic gene pools. The congruence of morphological and allozymic variation with chromosome numbers suggests a secondary contact between the two cytotypes with limited gene flow between them. The origin and persistence of the parapatric distribution are discussed. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
See detailEcologie chimique d’Eisenia fetida et son implication dans le lombricompostage
Zirbes, Lara ULg

Conference given outside the academic context (2009)

Detailed reference viewed: 28 (4 ULg)
See detailEcologie chimique d'Eisenia fetida et son implication dans le lombricompostage
Zirbes, Lara ULg

Master's dissertation (2007)

Detailed reference viewed: 103 (17 ULg)
Full Text
Peer Reviewed
See detailEcologie de la loutre (Lutra lutra) dans le Marais Poitevin 1. Etude de la consommation d'anguilles
Libois, Roland ULg; Rosoux, René

in Vie et milieu (1989), 39(3-4), 191-197

From 1982 to 1987, 165 otter scats samples were collected in the Marais Poitevin area (Western France). Eel was present in 158 of them. In our study area, eel was the main prey of the otter: its relative ... [more ▼]

From 1982 to 1987, 165 otter scats samples were collected in the Marais Poitevin area (Western France). Eel was present in 158 of them. In our study area, eel was the main prey of the otter: its relative frequency of occurrence in the otter's faeces amounted to 32.7% and its relative abundance to 40%. We did not find any dietary seasonal variation in terms of eel size or eel number. Prey size ranged from 9 to 65 cm (mean = 28 cm; n = 490) but mostly (75 %) less than 30 cm. In contrast these small individuals made up only 30% of the total eel weight represented by remains in the faeces. Eel size frequency distribution was compared in the otter's diet and in the rivers (data from Legault, 1987: electrofishing and fishing tackles). No significant difference was found, indicating that there was no selection at all in terms of prey size. [less ▲]

Detailed reference viewed: 54 (1 ULg)
Full Text
Peer Reviewed
See detailEcologie de la loutre (Lutra lutra) dans le Marais Poitevin 2. Aperçu général du régime alimentaire
Libois, Roland ULg; Rosoux, René

in Mammalia (1991), 55(1), 35-47

From 1982 to 1987, 165 otter spraints samples were collected in the Marais Poitevin area (Western France). Eel is the main prey whichever way the results are presented: relative occurrence, relative ... [more ▼]

From 1982 to 1987, 165 otter spraints samples were collected in the Marais Poitevin area (Western France). Eel is the main prey whichever way the results are presented: relative occurrence, relative abundance or relative biomass. Despite their high frequency or abundance in the spraints, other preys such as Atherina, mosquito-fish, stickelback, stone loach, bluegill or invertebrates, are quite negligible as far as biomass is considered. In turn, less frequent bigger preys (mammals, tenches) are of geater importance. Except for cyprinid fishes, more frequent in spring, no marked seasonal variations were found in the otters diet. [less ▲]

Detailed reference viewed: 51 (1 ULg)
Full Text
See detailEcologie de la loutre (Lutra lutra) et conservation de ses habitats riverains
Libois, Roland ULg

in Actes du 1er colloque international "gestion et préservation des ressoures en eau" (2004, September)

Detailed reference viewed: 44 (0 ULg)
Full Text
See detailEcologie de la loutre dans le Marais Poitevin III. Variations du régime et tactique alimentaire.
Libois, Roland ULg; Rosoux, René; Delooz, Etienne

in Cahiers d'Ethologie (1991), 11(1), 31-50

During the spring 1988, spraint samples were collected on the banks of 3 watercourses (one river and two canals) crossing the Marais Poitevin. Their general characteristics (flow rate, conductivity ... [more ▼]

During the spring 1988, spraint samples were collected on the banks of 3 watercourses (one river and two canals) crossing the Marais Poitevin. Their general characteristics (flow rate, conductivity, hydrographic regime) are quite different. The fish community of the two canals was sampled by electrofishing and we estimated the relative abundance of the different fish species. After a check of the reliability of our spraint analysis technique (feeding trials with captive otters), we made an estimate of the relative abundance of the prey items in the otters diet and an assessment of the length and of the weight of each individual fish preyed upon. They are indeed very strong length-weight correlations in fish and also close relationships between the length of some skull bones and the total length od a fish. The diet is mostly made up by the eel. It comprises also a great variety of other fish species, nearly all that were observend in the habitat. Much frogs, some snakes, birds, mammals, insects and crustaceans were also discovered. They are only slight diet differences between the main watercourses which probably are related to the characteristics of their fish fauna (e.g. much more sticklebacks when waters are becoming brackish; big amount of Atherina in salt marshes). No marked variations were found during a normal summer but fish is obviously less eaten during a severe drought. Comparing the frequency-distributions of fish in the diet and in the habitat, we found no selective predation in respect with fish (eel, cyprinids) size. From that point of view, the otter display a generalistic-opportunistic pattern of foraging. As far as the relative abundance of the various species is considered, otters take much less roaches and much more eels and tenches than present in the habitat. It remains to be seen if that is the consequence of a 'deliberate choice' or of a peculiar way of underwater huntig. A fact is that the otter principally eats bottom living fishes. [less ▲]

Detailed reference viewed: 39 (2 ULg)
Full Text
See detailEcologie des tritons au Pays de Herve: influence des habitats à plusieurs échelles
Denoël, Mathieu ULg; Perez, Amélie; Ficetola, G. Francesco

in Echo des Rainettes (2012), 10

Detailed reference viewed: 52 (7 ULg)
See detailEcologie du paysage : patrons / processus / design
Mahy, Grégory ULg

Scientific conference (2010, December 14)

Detailed reference viewed: 28 (8 ULg)
Full Text
See detailEcologie du paysage, anthropisation en Afrique tropicale, instruments et études de cas
Vranken, Isabelle ULg

Scientific conference (2013, November)

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailEcologie du paysage: cibler la configuration et l’échelle spatiale.
Bogaert, Jan ULg; Mahamane, A

in Annales des Sciences Agronomiques du Bénin (2005), 7(1), 39-68

Detailed reference viewed: 55 (20 ULg)
Full Text
Peer Reviewed
See detailEcologie du paysage: concepts, méthodes et applications (F. Burel, J. Baudry).
Bogaert, Jan ULg

in Landscape & Urban Planning (2001), 55(1), 70-72

Detailed reference viewed: 62 (10 ULg)