References of "Mahy, Grégory"
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See detailCan we restore natural habitats after plant invasion? Lessons from years of management
Frisson, Gwenn ULg; Halford, Mathieu ULg; Delbart, Emmanuel ULg et al

Conference (2010, August)

Negative impacts of invasive plants on natural habitats have been widely demonstrated. Hence, the management of invasive plants, aiming at eradicating, or at least controlling their spread, is being more ... [more ▼]

Negative impacts of invasive plants on natural habitats have been widely demonstrated. Hence, the management of invasive plants, aiming at eradicating, or at least controlling their spread, is being more and more developed. For this purpose, we need to identify the most efficient management techniques which could lead to the restoration of invaded ecosystems. Up to now, management methods mentioned in literature were pragmatic tools and often lacked scientific assessment. For several years, we have tested similar mechanical and chemical management techniques in the field on highly invasive plant species, representative of different life forms and invaded habitats: herbaceous rhizomatous perennial Fallopia japonica, ligneous rhizomatous Spiraea spp., ligneous root suckering Acer rufinerve and ligneous stoloniferous Cotoneaster horizontalis. We investigated the efficiency, cost and feasibility of these techniques, and their effects on the restoration of invaded ecosystems. The best performing management technique was found to be highly species specific and was also influenced by the invaded habitat type. For these perennial species, long-term management must be considered, to reduce their competitive capacities with repeated mechanical or chemical techniques (cutting or pulling out several times a year, injection combined with mechanical methods, etc.). For species with sexual reproduction, like Acer rufinerve and Cotoneaster horizontalis, seed bank and seed dispersal must also be taken into account to avoid dissemination when managing. We can conclude invasion plant management is usually expensive and hard to implement but some results are encouraging and show the importance to carry on research on invasive plant management methods. [less ▲]

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See detailSite Internet du projet AlterIAS
Halford, Mathieu ULg; Heemers, Leen; Mathys, Catherine et al

Computer development (2010)

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See detailPotentiel évolutif du complexe invasif Fallopia en Europe
Vanderhoeven, Sonia ULg; Saad, Layla ULg; Mahy, Grégory ULg

Scientific conference (2010, April)

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See detailDiversité des relations sol plantes dans les écosystèmes extrémophiles et implications pour la restauration : le cas des végétations cupricoles du Katanga, RDC.
Seleck, Maxime ULg; Lebrun, Julie ULg; Guillaume, Arielle ULg et al

Conference (2010, March 31)

Les collines de cuivre et de cobalt du Katanga (RDC) sont des milieux isolés présentant des substrats hautement toxiques (>10.000 ppm cuivre, gradients très marqués). De ce fait, ces gisements hébergent ... [more ▼]

Les collines de cuivre et de cobalt du Katanga (RDC) sont des milieux isolés présentant des substrats hautement toxiques (>10.000 ppm cuivre, gradients très marqués). De ce fait, ces gisements hébergent des communautés végétales originales, avec une diversité d’espèces métallophytes spécialisées, en relation étroite avec la concentration en métaux du sol. La récente reprise des activités minières dans la région menace grandement ces écosystèmes. La restauration de ces communautés végétales nécessite une compréhension fine des relations entretenues avec leur environnement édaphique et la caractérisation de la diversité intra et inter sites de ces communautés. Trois gisements ont fait l’objet d’une étude détaillée sur base d’un échantillonnage systématique en fonction du gradient à priori d’ETM. Dans des placette de 1m², un échantillon composite de sols a été prélevé à deux profondeurs : 0-15 cm et 30-45 cm et analysé pour : pH, Corg, N tot, Cu, Co, Zn, Mn, Fe, K, Mg, Ca et P biodisponibles. L’abondance des espèces présentes au sein des quadrats a été mesurée selon leur pourcentage de recouvrement. L’analyse en groupement et la mise en relation flore-sol par les méthodes de CCA indiquent que les sites présentent des conditions de sol et des végétations bien différenciées bien que les deux mêmes formations sont présentes. Les concentrations en cuivre sont un facteur explicatif important de la variation de la flore mais d’autres paramètres édaphiques s’avèrent également essentiels (Mg, Mn, K, Ca). Toutefois la sélection des paramètres édaphique expliquant la variation de la flore diffère d’un site à l’autre indiquant la grande diversité de ces écosystèmes et la nécessité de développer des approches de restauration spécifiques à chaque site. [less ▲]

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See detailLinking concepts in the ecology and evolution of invasive plants: network analysis shows what has been most studied and identifies knowledge gaps
Vanderhoeven, Sonia ULg; Brown, Cynthia; Tepolt, Carolyn et al

in Evolutionary Applications (2010), 3(2), 193-202

In recent decades, a growing number of studies have addressed connections between ecological and evolutionary concepts in biologic invasions. These connections may be crucial for understanding the ... [more ▼]

In recent decades, a growing number of studies have addressed connections between ecological and evolutionary concepts in biologic invasions. These connections may be crucial for understanding the processes underlying invaders' success. However, the extent to which scientists have worked on the integration of the ecology and evolution of invasive plants is poorly documented, as few attempts have been made to evaluate these efforts in invasion biology research. Such analysis can facilitate recognize well-documented relationships and identify gaps in our knowledge. In this study, we used a network-based method for visualizing the connections between major aspects of ecology and evolution in the primary research literature. Using the family Poaceae as an example, we show that ecological concepts were more studied and better interconnected than were evolutionary concepts. Several possible connections were not documented at all, representing knowledge gaps between ecology and evolution of invaders. Among knowledge gaps, the concepts of plasticity, gene flow, epigenetics and human influence were particularly under-connected. We discuss five possible research avenues to better understand the relationships between ecology and evolution in the success of Poaceae, and of alien plants in general. [less ▲]

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See detailTaxa distribution and RAPD markers indicate different origin and regional differentiation of hybrids in the invasive Fallopia complex in central-western Europe
Krebs, C.; Mahy, Grégory ULg; Matthies, D. et al

in Plant Biology (2010), 12(1), 215-223

Interspecific hybridization can be a driving force for evolutionary processes during plant invasions, by increasing genetic variation and creating novel gene combinations, thereby promoting genetic ... [more ▼]

Interspecific hybridization can be a driving force for evolutionary processes during plant invasions, by increasing genetic variation and creating novel gene combinations, thereby promoting genetic differentiation among populations of invasive species in the introduced range. We examined regional genetic structure in the invasive Fallopia complex, consisting of F. japonica var. japonica, F. sachalinensis and their hybrid F. × bohemica, in seven regions in Germany and Switzerland using RAPD analysis and flow cytometry. All individuals identified as F. japonica var. japonica had the same RAPD phenotype, while F. sachalinensis (11 RAPD phenotypes for 11 sampled individuals) and F. × bohemica (24 RAPD phenotypes for 32 sampled individuals) showed high genotypic diversity. Bayesian cluster analysis revealed three distinct genetic clusters. The majority of F. × bohemica individuals were assigned to a unique genetic cluster that differed from those of the parental species, while the other F. × bohemica individuals had different degrees of admixture to the three genetic clusters. At the regional scale, the occurrence of male-fertile F. sachalinensis coincided with the distribution of F. × bohemica plants showing a high percentage of assignment to both parental species, suggesting that they originated from hybridization between the parental species. In contrast, in regions where male-fertile F. sachalinensis were absent, F. × bohemica belonged to the non-admixed genetic group, indicating multiple introductions of hybrids or sexual reproduction among hybrids. We also found regional differentiation in the gene pool of F. × bohemica, with individuals within the same region more similar to each other than to individuals from different regions. [less ▲]

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See detailForest refugia revisited: nSSRs and cpDNA sequences support historical isolation in a wide-spread African tree with high colonization capacity, Milicia excelsa (Moraceae)
Daïnou, Kasso ULg; Bizoux, Jean-Philippe ULg; Doucet, Jean-Louis ULg et al

in Molecular Ecology (2010), 19

The impact of the Pleistocene climate oscillations on the structure of biodiversity in tropical regions remains poorly understood. In this study, the forest refuge theory is examined at the molecular ... [more ▼]

The impact of the Pleistocene climate oscillations on the structure of biodiversity in tropical regions remains poorly understood. In this study, the forest refuge theory is examined at the molecular level in Milicia excelsa, a dioecious tree with a continuous range throughout tropical Africa. Eight nuclear microsatellites (nuSSRs) and two sequences and one microsatellite from chloroplast DNA (cpDNA) showed a deep divide between samples from Benin and those from Lower Guinea. This suggests both that these populations were isolated in separate geographical regions, probably for several glacial cycles of the Pleistocene, and a poor mixture of gene pools despite M. excelsa’s wind-pollination syndrome. The divide can also be related to seed dispersal patterns, which should be largely determined by the migration behaviour of M. excelsa's main seed disperser, the frugivorous bat Eidolon helvum. Within Lower Guinea, a north-south divide, observed with both markers despite weak genetic structure (nuSSRs: FST=0.035, cpDNA: GST=0.506), suggested the existence of separate Pleistocene refugia in Cameroon and the Gabon/Congo region. We inferred a pollen-to-seed dispersal distance ratio of 1.76, consistent with wide-ranging gene dispersal by both wind and bats. Simulations in an Approximate Bayesian Computation framework suggested low nuSSR and cpDNA mutation rates but imprecise estimates of other demographic parameters, probably due to a substantial gene flow between the Lower Guinean gene pools. The decline of genetic diversity detected in some Gabonese populations could be a consequence of the relatively recent establishment of a closed canopy forest which may negatively affect M. excelsa's reproductive system. [less ▲]

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See detailColonization Credit in Restored Wet Heathlands
Cristofoli, Sara ULg; Piqueray, Julien ULg; Dufrêne, Marc ULg et al

in Restoration Ecology (2010), 18(5), 645-655

Although human-driven landscape modification is generally characterized by habitat destruction and fragmentation, it may also result in the creation of new habitat patches, providing conditions conducive ... [more ▼]

Although human-driven landscape modification is generally characterized by habitat destruction and fragmentation, it may also result in the creation of new habitat patches, providing conditions conducive to spontaneous colonization. In this article, we propose the concept of ‘‘colonization credit’’ (i.e., the number of species yet to colonize a patch, following landscape changes) as a framework to evaluate the success of colonization, in terms of species richness, in new/restored habitats, taking into account the spatial structure of landscapes. The method mirrors similar approaches used to estimate extinction debt in the context of habitat fragmentation, that is, comparisons, between old and new habitat patches, of the relationships among spatial patch metrics and patch species richness. We applied our method to the case of spontaneous colonization of newly created habitat patches suitable for wet heathland plant communities in South Belgium. Colonization credit was estimated for the total species richness, the specialist species richness, and the species richness of three emergent groups (EGs) of specialist species, delineated on the basis of dispersal traits. No significant colonization credit was identified either in patches created 25–55 years ago or in those created within the past 25 years, with the exception of species from our first EG (mostly anemochorous species with long-term persistent seed bank). However, the differential response of species in that first EG could not be explained through their characteristic life history traits. The results of this study are encouraging and suggest that deliberate, directed restoration activities could yield positive developments in a relatively short period of time. [less ▲]

Detailed reference viewed: 184 (41 ULg)
See detailTenke Fwaulu Sefu Ore Bodies Flora Baseline - Tenke Fungurume Mining Project
Lebrun, Julie ULg; Malaisse, François ULg; Handjila Minengo, Guylain et al

Report (2010)

Detailed reference viewed: 7 (0 ULg)
See detailTenke Fungurume Project - 2009 Flora New Ore Bodies Baseline Study - Annual Report
Lebrun, Julie ULg; Malaisse, François ULg; Handjila Minengo, Guylain et al

Report (2010)

Detailed reference viewed: 11 (0 ULg)
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See detailRenouées asiatiques: Fiche synthétique de gestion
Delbart, Emmanuel ULg; Mahy, Grégory ULg

Learning material (2010)

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See detailDes alternatives aux plants invasives: la prévention commence dans nos jardins!
Halford, Mathieu ULg; Vanderhoeven, Sonia; Heemers, Leen et al

Learning material (2010)

Detailed reference viewed: 12 (1 ULg)