References of "Mahy, Grégory"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailPatterns of hybridization and hybrid survival in the invasive alien Fallopia complex (Polygonaceae)
Saad, Layla ULg; Tiébré, Marie-Solange; Hardy, Olivier et al

in Plant Ecology and Evolution (2011), 144(12-18),

Background -- Hybridization and polyploidization are considered important driving forces of invasive processes. In the invasive Fallopia spp. complex, hybridization between taxa of various ploidy levels ... [more ▼]

Background -- Hybridization and polyploidization are considered important driving forces of invasive processes. In the invasive Fallopia spp. complex, hybridization between taxa of various ploidy levels has been experimentally demonstrated. Extensive genetic variation has also been observed among hybrids in the field. However, what makes a certain hybridization event of evolutionary importance is still the subject of speculation considering the invasive potential of hybrid Fallopia. Aims -- The present study examined landscape scale patterns of interspecific hybridization within the alien invasive Fallopia complex, and tested whether cold winter might act as selective agent for hybrid survival. Methods -- Eighty seeds per clone were collected from four taxa (F. japonica, F. sachalinensis, F. aubertii, and F. xbohemica) and sown in greenhouse and outdoor conditions. Ploidy levels of the resulting seedlings were determined by flow cytometry at early stages of seedling growth and compared to those of mature clones present in the same landscapes. Key results -- The four studied taxa were involved in interspecific hybridization patterns. Seedlings resulting from hybridization had a large range of ploidy levels, including aneuploid and euploid progeny, and polyploid levels that were not observed in mature clones. Cold winter had a negative effect on germination success. However, a comparison of ploidy levels of seedlings that survived the cold winter with those grown under greenhouse conditions indicated that cold winter was not a significant selection agent for particular ploidy levels. Conclusions -- Our results stress the importance of interspecific hybridization and polyploidization events in generating invasive hybrids in the alien Fallopia spp complex. Cold winter represents a selection agent for the survival of early stages of progeny but does not explain the discrepancies in ploidy levels between produced seedlings and currently occurring mature clones. [less ▲]

Detailed reference viewed: 78 (14 ULg)
See detailNos plans d’eau n’y échappent pas : les plantes amphibies invasives…
Delbart, Emmanuel ULg; Mahy, Grégory ULg

Article for general public (2011)

Detailed reference viewed: 26 (12 ULg)
Full Text
See detailDu coto sur nos coteaux. Une espèce exotique à tenir à loeil!
Piqueray, Julien ULg; Vanderhoeven, Sonia; Halford, Mathieu ULg et al

Article for general public (2011)

Detailed reference viewed: 21 (8 ULg)
Full Text
See detailPlantons autrement: Code de conduite sur les plantes invasives (dépliant de vulgarisation)
Halford, Mathieu ULg; Heemers, Leen; Mathys, Catherine et al

Learning material (2011)

Detailed reference viewed: 10 (1 ULg)
Full Text
See detailL’adaptation au changement climatique en région wallonne
EcoRes-TEC Conseil; Amelung, Bas; Biernaux, Martin et al

Report (2011)

Climate change is now globally accepted. The 4th IPCC report, published in 2007, clearly indicates that this phenomenon is mostly the result of human activity. All parts of the globe are potentially at ... [more ▼]

Climate change is now globally accepted. The 4th IPCC report, published in 2007, clearly indicates that this phenomenon is mostly the result of human activity. All parts of the globe are potentially at risk. There are no activity sectors that will be left untouched. Adaptation is therefore necessary. Since 2006, the European Commission has been looking at the climate change adaptation issue. It first held a consultation on the European Commission Green Paper “adapting to climate change in Europe - options for EU action”. This led to the publication of the White Paper « Adapting to climate change: towards a European framework for action ». In this document, the EC puts forward the idea of a compulsory Adaptation Strategy at Member State level. Several EU countries have already done so: Finland, United Kingdom and France. Belgium, through the National Climate Commission, adopted its « National Climate Strategy » in late 2010. The objective is to recommend an operational action plan by 2012. This action plan will be the result of a merger between the action plans of the three regions and the federal governments. The Flemish region launched a study to start the development process of their action plan in 2010; the Walloon region has followed with this study and the Brussels region and the Federal should launch their studies during this year (2011). This study enabled to draw a complete review – characteristics, current vulnerabilities, future vulnerabilities - of the Walloon region on seven topics: Agriculture, water, infrastructure/ spatial planning, health, energy, biodiversity and forests. An enlarged experts’ consultation identified key measures to implement in order for Wallonia to adapt to climate change. Chapter 1, « climate change adaptation in European regions », is a stock-taking exercise of adaptation strategies found in Europe in order to draw relevant lessons for this study. Chapter 2: « the climate futures of Wallonia”, is an analysis of the climate projection specifically carried out for this study. Those projections were used to identify Wallonia’s vulnerabilities. Chapter 3 « Wallonia’s vulnerabilities to Climate change” explores the seven themes Agriculture, water, infrastructure/ spatial planning, health, energy, biodiversity and forests to describe the current and future risks and to put forward a time-dependent and sectoral hierarchy of impacts. Chapter 4 « Wallonia’s adaptation to climate change » states the core principles used to define the adaptation choices as well as the proposed guidelines for each theme. Chapter 5 « towards an action plan » presents the adaptation measures by theme along with the first elements of an evaluation procedure. Finally, the appendices contain the operational documents: the full thematic sheets, the action plan, the strategic guideline paper and the transversal analysis and the supporting documents: maps, climate projections database and the benchmarks. [less ▲]

Detailed reference viewed: 139 (12 ULg)
Full Text
See detailL’adaptation au changement climatique en région wallonne : Fiche thématique : Forêt
Frisson, Gwenn ULg; Monty, Arnaud ULg; Mahy, Grégory ULg et al

Report (2011)

• Les changements attendus sont importants mais difficiles à quantifier. Seules des tendances peuvent être dégagées. • Pour le domaine de la forêt, il est d’autant plus nécessaire d’anticiper les effets ... [more ▼]

• Les changements attendus sont importants mais difficiles à quantifier. Seules des tendances peuvent être dégagées. • Pour le domaine de la forêt, il est d’autant plus nécessaire d’anticiper les effets du changement climatique dès maintenant, étant donné la longévité importante des arbres forestiers. • Favoriser l’adaptation naturelle et augmenter la résilience au changement de la forêt peut se faire au moyen d’une sylviculture plus durable et plus proche du fonctionnement naturel de l’écosystème forestier. Diminuer les menaces d’ordre non climatique participe également à cela. • La forêt ne doit pas seulement se mesurer en termes de valeur intrinsèque mais également en termes de services écosystémiques. [less ▲]

Detailed reference viewed: 72 (14 ULg)
Full Text
See detailL’adaptation au changement climatique en région wallonne : Fiche thématique : Biodiversité
Frisson, Gwenn ULg; Monty, Arnaud ULg; Mahy, Grégory ULg et al

Report (2011)

• Les changements attendus sont importants mais difficiles à quantifier. Seules des tendances peuvent être dégagées. • La fragmentation des habitats naturels est particulièrement poussée en Wallonie. Elle ... [more ▼]

• Les changements attendus sont importants mais difficiles à quantifier. Seules des tendances peuvent être dégagées. • La fragmentation des habitats naturels est particulièrement poussée en Wallonie. Elle constitue une lourde menace sur la biodiversité et une entrave aux changements d’aires de distribution attendus. • Développer le réseau écologique et diminuer les menaces qui pèsent actuellement sur la biodiversité est primordial pour donner une chance à la biodiversité de s’adapter au changement climatique. • Les impacts de la perte de biodiversité ne doivent pas seulement se mesurer en termes de valeur intrinsèque mais également en termes de services écosystémiques. [less ▲]

Detailed reference viewed: 35 (12 ULg)
Full Text
Peer Reviewed
See detailGestion de Crassula helmsii en Belgique plus difficile qu’il n’y paraît?
Delbart, Emmanuel ULg; Monty, Arnaud ULg; Mahy, Grégory ULg

in EPPO Bulletin (2011), 41

La crassule des e´tangs (Crassula helmsii) est une plante invasive (ou exotique envahissante) qui repre´sente un risque environnemental pour les milieux aquatiques en Belgique et, plus globalement, en ... [more ▼]

La crassule des e´tangs (Crassula helmsii) est une plante invasive (ou exotique envahissante) qui repre´sente un risque environnemental pour les milieux aquatiques en Belgique et, plus globalement, en Europe. Pour controˆler cette espe`ce, les acteurs de terrain disposent d’une litte´rature a priori abondante, ainsi que de plusieurs bases de donne´es relatives a` sa distribution spatiale. Néanmoins, les gestionnaires peuvent vite se sentir de´sarme´s, d’une part par le manque de clarte´ sur les moyens a` mettre en oeuvre afin d’endiguer la propagation de l’espe`ce et, d’autre part, par le manque d’exhaustivite´ des bases de donne´es. S’ajoute a` cela une insuffisance de litte´rature sur les vecteurs de dissémination a` travers les paysages. [less ▲]

Detailed reference viewed: 50 (16 ULg)
Peer Reviewed
See detailConservation of endangered plant communities: a study case of ecosystem reconstruction in Katanga (DRC)
Lebrun, Julie ULg; Handjila, Guylain; Bizoux, Jean-Philippe ULg et al

Conference (2011)

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 144 species were found in the ecosystem which represents more than 80% of the original species richness. The reconstructed ecosystem seems to favour the most tolerant species to copper. 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 ▲]

Detailed reference viewed: 142 (19 ULg)
Full Text
Peer Reviewed
See detailMay Rare Metallophytes Benefit from Disturbed Soils Following Mining Activity? The Case of the Crepidorhopalon tenuis in Katanga (D. R. Congo)
Faucon, Michel-Pierre; Parmentier, Ingrid; Colinet, Gilles ULg et al

in Restoration Ecology (2011), 19

Detailed reference viewed: 68 (23 ULg)
Full Text
Peer Reviewed
See detailTesting coexistence of extinction debt and colonization credit in fragmented calcareous grasslands with complex historical dynamics
Piqueray, Julien ULg; Cristofoli, Sara; Bisteau, Emmanuelle et al

in Landscape Ecology (2011), 26

Calcareous grasslands are among the most species-rich ecosystems in temperate countries. However, these ecosystems have suffered from fragmentation and destruction during the last century. We studied the ... [more ▼]

Calcareous grasslands are among the most species-rich ecosystems in temperate countries. However, these ecosystems have suffered from fragmentation and destruction during the last century. We studied the response of calcareous grassland plant diversity to landscape changes in Belgium. Results indicated that high area loss (since 1965) old habitat patches exhibited an extinction debt inverse to low area loss old habitat patches, little depending on the area loss threshold (60%, 70%, 80% or 90%) considered for the distinction between the high and low area loss patches. However, human activities also created new habitat patches in the landscape and therefore provided opportunities for calcareous grassland plant species to colonize new habitats. This also provided opportunities to study species colonization abilities in the context of habitat restoration. We analyzed species richness in new patches compared to old patches in order to detect colonization credit. We detected the presence of a colonization credit in new patches when using high loss old patches (area loss>80%, exhibiting an extinction debt) or all old patches as a reference. However, when the reference was low loss old patches alone (area loss<80%, less likely to exhibit an extinction debt), no colonization credit was detected. In addition, species composition was similar between new patches and old patches. These results are encouraging for restoration programs. However, the results indicated that the presence of an extinction debt in reference habitats could lead to inaccurate conclusions in restoration monitoring. Therefore, extinction debt should be considered when choosing reference habitats to evaluate restoration success. [less ▲]

Detailed reference viewed: 58 (19 ULg)
Full Text
Peer Reviewed
See detailPlant species extinction debt in a temperate biodiversity hotspot: community, species and functional traits approaches
Piqueray, Julien ULg; Bisteau, Emmanuelle; Cristofoli, Sara et al

in Biological Conservation (2011), 144

Destruction and fragmentation of (semi-) natural habitats are considered the main causes of biodiversity loss worldwide. Plant species may exhibit a slow response to fragmentation, resulting in the ... [more ▼]

Destruction and fragmentation of (semi-) natural habitats are considered the main causes of biodiversity loss worldwide. Plant species may exhibit a slow response to fragmentation, resulting in the development of an extinction debt in fragmented plant communities. The detection of extinction debt is of primary importance in habitat conservation strategies. We applied two different approaches proposed in the literature to identify extinction debt in Southeast Belgium calcareous grasslands. The first method compared species richness between stable and fragmented habitat patches. The second explored correlations between current species richness and current and past landscape configurations using multiple regression analyses. We subsequently examined results generated by both methods. In addition, we proposed techniques to identify species that are more likely to support extinction debt and associated functional traits. We estimated a respective extinction debt of approximately 28% and 35% of the total and specialist species richness. Similar results were obtained from both methods. We identified 15 threatened specialist species under the current landscape configuration. It is likely the landscape configuration no longer supports the species habitat requirements. We demonstrated that non-clonal species are most threatened, as well as taxa that cannot persist in degraded habitats and form only sparsely distributed populations. We discussed our results in light of other studies in similar habitats, and the overall implications for habitat conservation. [less ▲]

Detailed reference viewed: 73 (7 ULg)
Full Text
Peer Reviewed
See detailPerception and understanding of invasive alien species issues by nature conservation and horticulture professionals in Belgium
Vanderhoeven, Sonia; Piqueray, Julien ULg; Halford, Mathieu ULg et al

in Environmental Management (2011), 47

We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated ... [more ▼]

We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based. [less ▲]

Detailed reference viewed: 54 (19 ULg)
Full Text
Peer Reviewed
See detailRapid restoration of a species-rich ecosystem assessed from soil and vegetation indicators: the case of calcareous grasslands restored from forest stands
Piqueray, Julien ULg; Bottin, Gaëtan; Delescaille, Louis-Marie et al

in Ecological Indicators (2011), 11

Calcareous grasslands have long been recognized as biodiversity hotspots in Europe. However, in recent decades these ecosystems have seen rapid decline. In Belgium, more than 100 ha of calcareous ... [more ▼]

Calcareous grasslands have long been recognized as biodiversity hotspots in Europe. However, in recent decades these ecosystems have seen rapid decline. In Belgium, more than 100 ha of calcareous grasslands have been restored from oak coppices and pine forests since the 1990s. The aim of the present study was to provide a quantitative assessment of the success of these restoration efforts, using two sets of indicators: one related to soil conditions, the other related to vascular plant communities. Soil conditions were evaluated by comparing soil samples from pre-restoration forest stands, restored grasslands (3 age classes: 2-4 years; 5-8 years, 10-15 years) and reference grasslands. The analysis revealed no significant differences in soil N, P and K contents between pre-restoration forests and restored and reference grasslands. We observed a decrease in the mineralization rate indicators in both pre-restoration forests and recent grassland restorations, which was resorbed in older restorations. Floristic surveys revealed that plant species composition of older restorations was most like reference grasslands. However, some differences in species composition persisted after 15 years. Moreover, a few rare species did not colonise restored grasslands despite a close seed source. Non-recolonization by a set of species expected on calcareous grasslands may be due to dispersal limitation and higher cover by native invasive grasses in restored parcels. These results were discussed in term of implications for management. [less ▲]

Detailed reference viewed: 83 (37 ULg)
Full Text
See detailDes alternatives aux plantes invasives: plantons autrement - le jardin, un refuge pour la biodiversité
Mathys, Catherine; Halford, Mathieu ULg; Heemers, Leen et al

Book published by SPF Santé Publique, Sécurité de la Chaîne alimentraire et Environnement (2011)

Detailed reference viewed: 48 (4 ULg)
See detailEcologie du paysage : patrons / processus / design
Mahy, Grégory ULg

Scientific conference (2010, December 14)

Detailed reference viewed: 27 (8 ULg)
See detailBiodiversity indicators and baseline assessment
Mahy, Grégory ULg

Conference given outside the academic context (2010)

Detailed reference viewed: 15 (7 ULg)