References of "Mahy, Grégory"
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See detailWhich evolutionary mechanisms allow Senecio inaequidens DC. to face a changing climate? A synthesis
Monty, Arnaud ULg; Mahy, Grégory ULg

Poster (2010, September)

Plant populations are expected to face gradual climatic variation in the next decades. Understanding and quantifying evolutionary and non-evolutionary mechanisms allowing populations response to climate ... [more ▼]

Plant populations are expected to face gradual climatic variation in the next decades. Understanding and quantifying evolutionary and non-evolutionary mechanisms allowing populations response to climate is therefore crucial to anticipate the actual consequences of climate change on plants. However, studying the direct effects of climate change in wild populations is of little anticipating interest… there invasive plants can help! We studied the sources of phenotypic variation in populations that gradually invaded different climatic zones over the last century, and assessed the role of local adaptation, non-adaptive genetic differentiation, phenotypic plasticity and environmental maternal effects in plant population response to climate. [less ▲]

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See detailEcology and evolution of invasive plants: what to study next?
Monty, Arnaud ULg; Brown, Cynthia; Tepolt, Carolyn et al

Poster (2010, September)

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 detailCan we really get rid of Japanese knotweed clones? Two years of management tests in Belgium
Monty, Arnaud ULg; Delbart, Emmanuel ULg; Mahy, Grégory ULg et al

Poster (2010, September)

Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for managers facing the invasion of this ... [more ▼]

Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides and two application methods (spraying and stem injection), as well as mechanical treatments, on Fallopia clones throughout southern Belgium. The tested methods were selected to be potentially usable by Belgian managers, e.g. using legally accepted rates for herbicides. Stem volume, height and density reduction was assessed after one or two years depending on the treatment. No tested method allowed a complete eradication of the clone. However, stem injection with glyphosate-based herbicide caused the highest damage. The year following injection, no sprouts were observed. Two following year, however, stunted shoots sprouted. Among mechanical control measures, repeated cuts combined with native trees cuttings plantations most appreciably reduced knotweed development. The most efficient methods we tested appear as tools for curbing knotweed invasion but are not likely to be used to eradicate the species. As such they should be included in a more integrated control strategy, together with prevention and public awareness campaigns. [less ▲]

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See detailCotoneaster horizontalis on calcareous grasslands in Belgium : from ornament to management
Frisson, Gwenn ULg; Piqueray, Julien ULg; Halford, Mathieu ULg et al

Poster (2010, September)

Cotoneaster horizontalis DECAISNE, a Rosaceae coming from Asia, was introduced in Belgium as an ornamental species. Different sides of the invasion were studied, from the distribution of the species and ... [more ▼]

Cotoneaster horizontalis DECAISNE, a Rosaceae coming from Asia, was introduced in Belgium as an ornamental species. Different sides of the invasion were studied, from the distribution of the species and the invasion status, the impacts, to management methods. To describe the invasion status, information was gathered about the occurrence and the distribution of the species in Belgium by compiling various databases. The naturalization status in calcareous grasslands, high-value habitats recognized as biodiversity hotspots, was assessed. Occurrence, population status, preferred habitats, invaded communities, growth rate and fruiting capacity were characterized. Once naturalization established, we investigated its impacts on calcareous grasslands communities, individual species and pollinators. C. horizontalis occurred in seven of the nine studied calcareous grasslands, with densities from 0.34 to 10 individuals/ha. In the most invaded sites, an ongoing colonization process was suggested by a high proportion of small individuals. Moreover, 3-year-old individuals already showed fruiting capacities. Germination rate reached about 30%. Significant impacts on habitat structure and vegetation were showed. Community structure and composition changes were demonstrated in invaded sites by decreasing species richness and diversity. As calcareous grasslands are priority Natura2000 habitats, measures must be taken to control the spread of C. horizontalis. For this purpose, we performed management tests to identify the most efficient techniques that would help the restoration of calcareous grasslands. Both mechanical and chemical management techniques were tested. Methods choice was driven by the environmental constraints of calcareous grasslands, which require highly selective techniques, and by species characteristics. Tested methods were cuttings, stump burning, spraying, cutting plus glyphosate application on stump and glyphosate application on stem basis. Efficiency, cost, feasibility and side-effects on ecosystems were estimated. Management tests are still ongoing but some results have already been drawn: spraying and single cutting are not efficient, the last one generating production of numerous sprouts. Finding the best management method will not be sufficient to stop the invasion. C. horizontalis is still present in 53% of the sale catalogs of horticulturists in Southern Belgium. As long as the species is used in the vicinity of calcareous grasslands, propagules are continuously provided, jeoparding management actions. [less ▲]

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See detailMining and Biodiversity: The Study Case of Ecosystem Reconstruction in Katanga (DRC)
Lebrun, Julie ULg; Semereab, Ezana; Rensonnet, Audrey et al

Conference (2010, September)

The Katangan copper-cobalt deposits (Democratic Republic of Congo) are part of the Central African Copperbelt, one of the world’s greatest metallogenic province. The ore comes to the surface in a series ... [more ▼]

The Katangan copper-cobalt deposits (Democratic Republic of Congo) are part of the Central African Copperbelt, one of the world’s greatest metallogenic province. The ore comes to the surface in a series of hills isolated in the miombo woodland. These unique ecosystems present high metals concentration levels where a specific vegetation develops. Flora comprises more than 600 species from which 30 are endemics. Due to the recent revival of mining activities in the region, copper plant communities of Katanga and their associated flora are now critically threatened. Tenke Fungurume Mining sarl (TFM), an important mining company operating in Katanga, has developed a Biological Diversity Action Plan (BDAP) to conserve copper-cobalt flora and mitigate potential species extinction risk. One of the most original BDAP tasks is an ecosystem reconstruction experiment that should preserve plant communities representative of the diversity found on the exploited hill and to provide the plant material for further post-exploitation restoration. From December 2007 to April 2009, full vegetation blocks were translocated with their soil mat on an adequate mineral substrate of 1500m². Since 2008, the artificial ecosystem is monitored every year. Three communities were successfully recreated. A total of 125 species were found in the ecosystem which represents half of the original species richness. Population size decreased for only 12 out of 32 surveyed species. This first experience shows that ecosystem reconstruction is successful and may be used as a strategy to conserve copper-cobalt plant communities in their habitat. [less ▲]

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See detailSoil-plants relations diversity in extreme ecsystems and implications for restoration: the case of the cupriferous vegetation, in Katanga, D.R. Congo
Seleck, Maxime ULg; Guillaume, Arielle; Lebrun, Julie ULg et al

Conference (2010, August 25)

Katangan copper and cobalt hills in the D. R. Congo are isolated ecosystems on highly toxics substrates (>10.000 ppm Cu, with strongly marked gradients). As a result, those outcrops host singular vegetal ... [more ▼]

Katangan copper and cobalt hills in the D. R. Congo are isolated ecosystems on highly toxics substrates (>10.000 ppm Cu, with strongly marked gradients). As a result, those outcrops host singular vegetal communities – with a diversity of specialized metallophytes species – related to soil metals content. Recent resumption of mining activities in the area threatens those ecosystems. To allow the restoration of those communities a fine understanding of the relationship maintained with the edaphic factors is required, as well as a characterization of the intra and inter sites variation. Three outcrops have been studied on the basis of a systematic grid, following the a priori trace elements gradient. In 1m² quadrats, a composite soil sample (0-15 cm depth) was taken and the cover (%) of each species of vascular plants was recorded. Soils were analyzed for pH, C, N, and bioavailables Cu, Co, Zn, Mn, Fe, K, Mg, Ca and P. The cluster analysis and Canonical Correspondence Analysis show that different sites present different soil conditions and vegetation. Concentrations in Cu are an important explicative factor of the flora’s variation but gradients in others edaphic parameters (pH, Mg, Mn, K, Ca) appear to be essential. However, parameters explaining the diversity of communities vary from one site to another indicating a great diversity of those ecosystems and the need to develop restoration strategies relevant for each site. [less ▲]

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See detailSoil seed bank of calamine sites in Belgium: what could be learned for original metallophytes communities restoration?
Bizoux, Jean-Philippe ULg; Mahy, Grégory ULg

Conference (2010, August)

Metalliferous sites often host rare, ecologically endemic taxa adapted to high levels of heavy metals in soils. In Belgium, these sites correspond to Calamine sites. They are often considered as waste ... [more ▼]

Metalliferous sites often host rare, ecologically endemic taxa adapted to high levels of heavy metals in soils. In Belgium, these sites correspond to Calamine sites. They are often considered as waste ground dangerous for human health and public authorities are inclined to promote site remediation by fertilization, ground supply or removal, building ... In the present study, we analysed the seed bank of two ancient calamine sites in order to precise strategies for restoration of calamine original communities by top soil removal and perturbation. Composite soil samples were taken in 5 facies in two sites corresponding to different association. Cores were divided in three layers: litter, 0-5 cm, 5-10 cm. The total number of taxa was 24 taxa at Theux and 15 at Schmalgraf. The most abundant species (68%) are Agrostis capillaries and Viola calaminaria. Seed bank composition appeared different between facies except for three species. The seed bank was dominated by pseudo metallophytes species in Schmalgraf and by metallophytes or other species in Theux. The majority of the species didn’t present significant difference of number of seed between the three layers, except seven species (A. capillaries, V. calaminaria, Silene vulgaris, Minuertia verna, ...) with significant lower number of seed in the layer 5-10 cm. Our result showed that soil seed bank composition reflect well vegetation communities of the two sites. In addition, because pseudo-metallophyte species as Agrostis capillaries dominated seed bank when they were present in the vegetation, soil removal must be used with parsimony to restore original communities. [less ▲]

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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 ▲]

Detailed reference viewed: 57 (14 ULg)