References of "Mahy, Grégory"
     in
Bookmark and Share    
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: 78 (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: 85 (38 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: 28 (8 ULg)
See detailBiodiversity indicators and baseline assessment
Mahy, Grégory ULg

Conference given outside the academic context (2010)

Detailed reference viewed: 15 (7 ULg)
Peer Reviewed
See detailConservation of endemic plants from the Katanga copper belt (DR Congo)
Lebrun, Julie ULg; Minengo Handjila, Guylain; Weiskopf, Thomas et al

Poster (2010, December)

The Katanga copper belt, where natural outcrops of copper-rich rocks are colonised by highly original plant communities, has been recognised as a hotspot for metallophyte species. The flora comprises more ... [more ▼]

The Katanga copper belt, where natural outcrops of copper-rich rocks are colonised by highly original plant communities, has been recognised as a hotspot for metallophyte species. The flora comprises more than 600 species from which 30 are endemics. These plants represent a valuable phytogenetic resource for revegetation and restoration programs, for the phytostabilisation and for the remediation of heavy metal pollutions. However, the flora of metalliferous soils is threatened by mining activities in Katanga. Actions aiming at preserving these species are therefore urgent. Since 2007, a unique conservation project has been launched by scientists supported by a mining company. The aim is to elaborate a program that allows biodiversity conservation while being compatible with mining activities. The project combines in-situ and ex-situ conservation strategies involving ecosystem reconstruction, species translocations, protected areas designation and the development of seed banks in Belgium and in Katanga. [less ▲]

Detailed reference viewed: 130 (27 ULg)
See detailGestion des invasives en Belgique : Une approche multi-facettes De la prévention à l’éradication
Mahy, Grégory ULg; Branquart, Etienne

Conference (2010, November 18)

Detailed reference viewed: 18 (1 ULg)
Full Text
See detailPaysages - Climats : Vers de Nouveaux Horizons
Mahy, Grégory ULg

Scientific conference (2010, October 05)

Detailed reference viewed: 14 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 40 (9 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 70 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 134 (12 ULg)
Full Text
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 ▲]

Detailed reference viewed: 81 (8 ULg)