References of "Mahy, Grégory"
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See detailLes messicoles, fleurs des moissons
Legast, Marie ULg; Mahy, Grégory ULg; Bodson, Bernard ULg

Book published by Claude Delbeuck/Direction générale de l'Agriculture (2008)

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See detailSeed rain pattern of the invasive weed Senecio inaequidens (Asteraceae)
Monty, Arnaud ULg; Stainier, Charles; Lebeau, Frédéric ULg et al

in Belgian Journal of Botany (2008), 141(1), 51-63

Dispersion capacity of alien invasive plants is a key feature for understanding invasion processes and risks. Here, we present an experimental study focussing on the seed rain pattern of Senecio ... [more ▼]

Dispersion capacity of alien invasive plants is a key feature for understanding invasion processes and risks. Here, we present an experimental study focussing on the seed rain pattern of Senecio inaequidens, an African plant widespread throughout Europe, under common favourable dispersal conditions. One hundred achenes from two Belgian populations underwent a drop time in still air experiment in order to assess linear correlation between several morphological traits and terminal velocity. Variation in morphological traits was measured for 250 additional achenes per population. The trait best correlated to terminal velocity was the square root of the plume loading. We then used this trait to model terminal velocity using a linear regression (r(2) of 79.7%). With this regression and imposing ecological parameters such as wind speed, turbulences and height of release to be representative of favourable dispersal conditions, we established a Gaussian tilted plume model to predict the seed rain pattern of the species. A wind tunnel experiment consequently permitted to validate the model. Under a wind speed of 5 m s(-1) with 2% turbulences along the vertical axis, and height of release of 0.40 m, 99.8% of achenes were dispersed within 100 meters, with a maximum deposition rate at 5.2 m from the parent plant. Uplifted achenes, not forecasted by the model, represent 6.25% of all achenes. [less ▲]

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See detailRestoration assessment of calcareous grasslands in Belgium : soil conditions and floristic diversity
Piqueray, Julien ULg; Bottin, Gaëtan; Bisteau, Emmanuelle et al

Conference (2008)

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See detailHybridisation efficiency in generating Hybridisation efficiency in generating invasive progeny in the alien Fallopia (Polygonaceae) complex
Saad, Layla ULg; Tiébré, Marie-Solange; Hardy, Olivier et al

Poster (2007, November 16)

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See detailLes landes et pelouses sur sable du Brabant sablo-limoneux (Première partie)
Taymans, Julien ULg; Mahy, Grégory ULg

in Parcs & Réserves (2007), 62(3), 10-16

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See detailPhytoremediation of contaminated sites in urban environment : preliminary results of a study focussed on Lubumbashi.
Colinet, Gilles ULg; Saad, Layla ULg; Cubaka, Alfred et al

Conference (2007, July)

A specific flora has developped in Central Africa on soils which are naturally rich in Cu and Co. Mining and ore treatment activities in the Katanga province (RDC) have generated contaminations which do ... [more ▼]

A specific flora has developped in Central Africa on soils which are naturally rich in Cu and Co. Mining and ore treatment activities in the Katanga province (RDC) have generated contaminations which do endanger ecosystem viability and/or human health. A survey of edaphic conditions prevailing for plant growing in natural metalliferous outcrops, the « copper hills », in mining sites (quarries), and in contaminated areas around metal smelters, is conducted as a first stage of a phytoremediation-based research program. Soluble, available and total content in some metallic trace elements have been measured. The first results show a relatively high heterogeneity inside and between sites. But the main finding is related to the very different nature of contamination between the three types of sites. This point constitutes an additionnal difficulty that should be taken into account for the selection of metallophytic species from the copper hills or the quarries in order to vegetalize a site contaminated by atmospheric fall outs from metal smelters in Lubumbashi. [less ▲]

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See detailLes invasions biologiques
Vanderhoeven, Sonia ULg; Branquart, Etienne; Grégoire, Jean-Claude et al

in Forêt Wallonne (2007), 89

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See detailHybridization And Sexual Reproduction In The Invasive Alien Fallopia (Polygonaceae) Complex In Belgium
Tiebre, Ms.; Vanderhoeven, Sonia ULg; Saad, Layla ULg et al

in Annals of Botany (2007), 99(1), 193-203

† Background and Aims The knotweed complex, Fallopia spp. (Polygonaceae), belongs to the most troublesome invasive species in Europe and North America. Vegetative regeneration is widely recognized as the ... [more ▼]

† Background and Aims The knotweed complex, Fallopia spp. (Polygonaceae), belongs to the most troublesome invasive species in Europe and North America. Vegetative regeneration is widely recognized as the main mode of reproduction in the adventive regions. However, the contribution of sexual reproduction to the success of these invasive species has only been detailed for the British Isles. An examination was made as to how hybridization may influence the sexual reproduction of the complex in Belgium and to determine how it may contribute to the dispersal of the species. † Methods Studies were made of floral biology, reproductive success, seed rain, seed bank, germination capacity, seedling survival and dispersal capacity in order to characterize the reproductive biology of the species. Moreover, chromosome counts and flow cytometry were used to assess the hybrid status of seedlings produced by sexual reproduction. † Key Results In the area investigated, extensive sexual reproduction by hybridization within the complex, including one horticultural species, was demonstrated. A small percentage of seeds may be dispersed outside the maternal clone (.16 m) allowing the formation of genetically differentiated individuals. Seed germination was possible even after a winter cold period. †Conclusions The extensive sexual reproduction by hybridization could further contribute to the dramatic invasive success of knotweeds in Belgium and should not be underestimated when considering control and management measures. [less ▲]

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