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See detailDynamique de défense du nid chez Symphodus ocellatus (Forsskål, 1775), poisson labridé méditerranéen. II. Comportements agressifs du mâle territorial nidificateur envers des mollusques gastéropodes
Ylieff, Marc ULg; Michel, Christian ULg; Voss, Jacques

in Cahiers d'Ethologie (1998), 18(1), 39-52

This field research examines aggressive behaviour towards gasteropod molluscs in nesting territorial male of Symphodus ocellatus. This behaviour is useful for brood and nest defense. Four questions ... [more ▼]

This field research examines aggressive behaviour towards gasteropod molluscs in nesting territorial male of Symphodus ocellatus. This behaviour is useful for brood and nest defense. Four questions involving Symphodus ocellatus towards gasteropod molluscs were investigated. Questions of interest were: (1) selective cleaning of the nest according to possible predation danger of molluscs on the eggs, (2) visual recognition of natural mollusc from artificially coloured lure, (3) colours discriminating abilities by the visual system and, more generally (4) the importance of territorial male investment in nest defense; this role could ensure a successful reproduction of the species. Our observations and experimentations (coloured dummies) allow us to conclude that in Symphodus ocellatus, nesting territorial males clean every time their nest, any gasteropod mollusc species whatever; that they have sufficient knowledge of their usual biological environment to be able to discriminate a gasteropod mollusc from a dummy; that the organ of perception used for social recognition is the visual channel constituted by a neural system competent to perceive colours finely , a special quality which support the theory about the use of one preferential colour (red for S.ocellatus) for visual communication; that fry protection insured by territorial male, a task guided by his visual system, is necessary considering dangers from some gasteropod molluscs living in his habitat. [less ▲]

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See detailDynamique de l'adaptation au temps et modèle de l'horloge interne
Ferrara, André ULg

Doctoral thesis (1999)

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See detailDynamique de la filière viande de brousse dans la partie continentale du Rio Muni en Guinée équatoriale
Njikam Nsangou, Ibrahim ULg

in Tropicultura (2004), 22(4), 204-210

The aim of this study was to do surveys about bush meat networks around urban centers near the Monte Alen National Park in Equatorial Guinea. During 8 weeks, in the Mundoasi market, one of two principal ... [more ▼]

The aim of this study was to do surveys about bush meat networks around urban centers near the Monte Alen National Park in Equatorial Guinea. During 8 weeks, in the Mundoasi market, one of two principal market of Bata, 4328 wild animal carcases have been indexed, representating 22,600 kg of biomass. A total of 48 animals species have been identified, including 14 which hunting are prohibited. The mammals represent 91.87% of total number with 3 dominants orders, ungulates (37.7%), primates (28.6%) and rodents (18%). The duiker (Cephalophus), the African Brushtailed Porcupine and Guenon are the most important. The district of Niefang, Bata and Evinayong are the principal sources of supply. Hunting with gun becomes very important, follow by snaring, a very wasteful method. Despite that this business squarely growth, signs of wildlife decrease are perceptible, showing evidence of overexploitation. As far as Monte Alen National Park is concerned, this study shows the positive effects of this protected area as wildlife reservoir for peripheral hunting zones. [less ▲]

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See detailDynamique de la haute atmosphère de Vénus
Stiepen, Arnaud ULg

Book published by Editions Universitaires Européennes (2014)

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See detailDynamique de la végétation d'altitude en Afrique centrale atlantique depuis 17 000 ans BP. Analyses préliminaires de la carotte de Bambili (Nord-Ouest du Cameroun).
Assi Kaudjhis, Chimène Cloche M ULg; LEZINE, ANNE - MARIE; Roche, Emile ULg

in Geo-Eco-Trop : Revue Internationale de Géologie, de Géographie et d'Ecologie Tropicales (2008), 32

This article presents the preliminary results of pollen analyses carried out on a 13.5m long core taken from the shore of the crater lake of Bambili, Cameroon (05°56'11.9N; 10°14' 31.6E; 2273m alt.). This ... [more ▼]

This article presents the preliminary results of pollen analyses carried out on a 13.5m long core taken from the shore of the crater lake of Bambili, Cameroon (05°56'11.9N; 10°14' 31.6E; 2273m alt.). This allows us to reconstruct the history of montane forest ecosystems from Atlantic Central Africa since 17 000 years BP. Well diversified microflora, show several changes. At the base of the pollen sequence, the vegetation is dominated by herbaceous plant populations such as Poaceae, associated with “dry” plant types from Amaranthaceae/ Chenopodiaceae families and tree and shrub plant types from savannas and open forest formations types such as Gnidia, Lannea, Combretaceae, Cussonia… The montane forest expansion started from 14 080cal BP with the appearance of the pioneer taxon Myrica. This taxon is followed by Schefflera, Podocarpus, Olea, Syzygium… which widely expanded in the immediate surroundings of the lake from 12 310 to 4 590 cal BP. After this date, the montane forest was strongly reduced. However a short phase of forest regrowth is recorded around 2000 BP during which Schefflera dominated the forest assemblage. [less ▲]

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See detailDynamique de modification de l'habitat physique de reproduction des pondeurs lithophiles sous gravier. Cas de deux frayères à ombre dans l'Aisne
Parkinson, Denis; Petit, François ULg; Houbrechts, Geoffrey ULg et al

in Bulletin de la Société Géographique de Liège (2001), 40

D’octobre 1998 à mars 1999, nous avons étudié dans l’Aisne, petit affluent ardennais de l’Ourthe, la dynamique de modification de deux bancs de gravier utilisés comme frayère par l’ombre commun en mars ... [more ▼]

D’octobre 1998 à mars 1999, nous avons étudié dans l’Aisne, petit affluent ardennais de l’Ourthe, la dynamique de modification de deux bancs de gravier utilisés comme frayère par l’ombre commun en mars-avril 1998. L’étude a été réalisée dans deux stations du cours inférieur de l’Aisne où se sont succédé quatre crues morphogènes. Dans chaque station, nous avons déterminé à intervalle d’environ 1 mois, la profondeur d’érosion et la hauteur de dépôt des sédiments (méthode de la barre d’érosion à chaînes), la granulométrie des matériaux des couches de surface et de subsurface, le dépôt des sédiments fins (placement de pièges à sédiments) et la perméabilité du substrat (méthode du standpipe). En complément, nous avons entrepris dans une station de l’Aisne moyenne, une caractérisation de divers éléments de la dynamique fluviale : identification des débits mobilisateurs (par marquage colorimétrique des sédiments en place), estimation de la vitesse de déplacement de la charge de fond (par étude de la dispersion longitudinale de scories, résidu d’anciennes industries métallurgiques) et estimation des quantités de sédiments charriés par la rivière (à partir des données de dragage). [less ▲]

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See detailDynamique de population de la Pie-grièche écorcheur (Lanius collurio) dans le sud-est de la Belgique : modélisation de l’influence du climat.
Metzmacher, Maxime ULg; van Nieuwenhuyse, Dries

in Revue d'Ecologie (La Terre et la Vie) (2012), 67(4), 353-374

In some areas of Western Europe, red-backed shrike populations, following a strong decline in the third quarter of the 20th century, were re-established in recent decades. Variations in climate seem to ... [more ▼]

In some areas of Western Europe, red-backed shrike populations, following a strong decline in the third quarter of the 20th century, were re-established in recent decades. Variations in climate seem to have played a crucial part in this striking evolution by modulating the species breeding success. In order to test this hypothesis, the annual fluctuations of several of these populations in south-eastern Belgium were compared with the variations in a series of climatic factors. This study derives from a number of censuses, completed during the breeding period between 1979 and 2008, and the data from the weather stations closest to the populations studied. The modelling of climate influence on annual population fluctuations is based on a Partial Least Squares regression (PLS), following the classification of variables using a latent variable approach. From 1980 to 2008, for the April-August period, the mean minimum temperature tended to rise. During these five months, rainfall intensity reached a minimum in the 1990’s and increased significantly thereafter. During the three last decades, rainfall intensity for June tended to decrease whereas that for August increased. The annual variations of these monthly averages were very high. As for breeding population fluctuations, our results highlighted the significant role of various parameters related to minimum temperature and pluviometry during the breeding period. Spring and cold wet summer periods seem to have a significant negative impact on the rate of breeder recruitment. These results suggest that the breeding success of red-backed shrike can benefit from global climate change due to the higher success rate of broods. This however applies provided that its habitat is preserved – in terms of quality and surface area – and that this warming does not generate overly high rainfall during a critical period of its breeding cycle. The importance of climatic factors in population fluctuations for this shrike provides opportunities for further investigation, particularly in studying the mechanisms that underlie these variations. [less ▲]

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See detailDynamique des constructions maritimes et offshores
Marchal, Jean ULg

Learning material (1979)

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See detailDynamique des forêts irrégulières et mélangées: de la modélisation aux recommandations sylvicoles
Ligot, Gauthier ULg

Conference (2014, April 29)

Close-to-nature management of forests has been increasingly advocated and practiced. However forest managers often face difficulties in maintaining the mixture of species with different shade tolerance ... [more ▼]

Close-to-nature management of forests has been increasingly advocated and practiced. However forest managers often face difficulties in maintaining the mixture of species with different shade tolerance. We studied this issue in uneven-aged acidophile medio-European beech forests. In these forests, while forest management has achieved regular timber production, it has rarely succeeded in promoting a diversified natural regeneration. In view of this, our objective is to refine our knowledge about the dynamic of uneven-aged mixed forests using a modelling approach. A set of consistent models were carried out to describe stand dynamic with, in particular, models of regeneration growth and light interception. The models were then implemented in a simulator in order to perform prospective analysis. In contrast to expectations, we found that saplings of beech, the shade-tolerant species, had the highest height growth rate at all light levels. Beech saplings reached an optimum growth at transmittance of 10%, whereas oak saplings needed more than 20%. These results indicate that oak saplings are systematically outcompeted by beech saplings across the light gradient. Thus, the control of canopy opening is not sufficient to promote the natural regeneration of oak beneath a stand also containing beech. Taking into account these latter results, we compared cutting strategies varying in type and intensity. Creating gaps of about 500 m² provided adequate light for small regeneration clumps. Cutting from below, species-specific cutting and uniform cutting were also appropriate but uniform cutting required higher harvest intensity. Cutting from above weakly increased understory light and promoted rather shade tolerant species. Finally we provided indications on different strategies that promote the regeneration of less-shade tolerant species, depending on the spatial aggregation of saplings, and the desired post-harvest stand structure and composition. [less ▲]

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See detailDynamique des groupes, dispositif de formation et apprentissage
Faulx, Daniel ULg

in Cahiers Internationaux de Psychologie Sociale (2010), 86(2), 345-349

Etude d'une expérience structurée questionnant les liens entre la dynamique d'un groupe et l'apprentissage qui peut être développé par les apprenants. Au centre du propos, le lien entre la dynamique de ... [more ▼]

Etude d'une expérience structurée questionnant les liens entre la dynamique d'un groupe et l'apprentissage qui peut être développé par les apprenants. Au centre du propos, le lien entre la dynamique de groupe, en partie stimulée par le dispositif, et les effets d'une action de formation. [less ▲]

Detailed reference viewed: 210 (22 ULg)
See detailDynamique des inégalités et fragilités sociales à la lumière du rapport entre emploi, famille et sécurité d'existence
Gavray, Claire ULg; Born, Michel ULg

Book published by Service Fédéraux des Affaires Scientifiques, Techniques et Culturelles (1995)

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See detailDynamique des nouveaux Systèmes Locaux de Santé (SYLOS) en 2013
Belche, Jean-Luc ULg

Scientific conference (2013, November 26)

Présentation de la dynamique Sylos dans 3 contextes locaux en région liégeoise en 2013 (Wallonie-belgique).

Detailed reference viewed: 33 (3 ULg)
See detailDynamique des paysages forestiers et savanicoles du Sud et du Nord-Est du Burundi
Havyarimana, F; Bigendako, M J; Bogaert, Jan ULg et al

Poster (2012)

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See detailDynamique des populations de trois adventices des céréales en vue de la mise au point de méthodes intégrées de leur contrôle
Vandersteen, Joëlle ULg; Bodson, Bernard ULg

in Bodson, Bernard; de proft, Michel (Eds.) Livre Blanc 2011 (2011, February 23)

Detailed reference viewed: 13 (3 ULg)