References of "Mahy, Grégory"
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See detailPerformance Indicators Framework for Biodiversity Management in Gypsum Quarries Throughout Europe
Pitz, Carline ULg; Mahy, Grégory ULg; Marlet, Christine et al

Report (2013)

This study aims to establish a common Key Performance Indicators (KPIs) framework to report biodiversity for the Gypsum Industry at the European level. An original approach of participatory process has ... [more ▼]

This study aims to establish a common Key Performance Indicators (KPIs) framework to report biodiversity for the Gypsum Industry at the European level. An original approach of participatory process has been developed in order to integrate the different opinions and to reach a consensus framework between different stakeholders’ groups: - Eurogypsum stakeholders - European and local authorities - Scientific panel : universities and consulting offices - European and local associations for the conservation of nature - Stakeholders from the mining sector The strategy is based on five main steps: (i) To Build a stakeholders’ network; (ii) To build a framework proposal to be submitted to stakeholders by selecting a maximum set of indicators based on the literature and reaching an agreement on indicators with Eurogypsum (Focus Group); (iii) Reaching a consensus framework with all the stakeholders and evaluating feasibility by a Delphi Policy survey, by the analysis of the EIAs of the Gypsum Industry and by visiting three European quarries; (iv) Final validation with Eurogypsum (meeting); (v) Creating indicators’ Factsheets and a Eurogyspum report to the destination of the public. The resulting framework contains eleven indicators which are the most acceptable set of indicators for all the stakeholders. It answers to European legislation and strategies for biodiversity. It is intended to improve sustainability in the quarries and to help managing biodiversity, to allow setting up of appropriate reporting systems. The aim is to maintain the biodiversity status of the gypsum quarries. It is a flexible framework adaptable given the local context of each gypsum quarry in order to prove if a No Net Loss has been reached at a quarry’s scale. [less ▲]

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See detailSynthesis and new definition of the areas included in the urban-rural gradient
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

Conference (2013, July 26)

Every scientific studies should begin with the delimitation of the studied system. Ours aims at evaluating and quantifying the resistence of landscape classes and ecosystems to the urbanization process ... [more ▼]

Every scientific studies should begin with the delimitation of the studied system. Ours aims at evaluating and quantifying the resistence of landscape classes and ecosystems to the urbanization process. This is done by studying a dozen cities in sub-Saharan Africa, conducting a diachronic (2000 - 2010) landscape evolution analysis from SPOT satellite imagery. Paradoxaly, when tackling this subject, one must recognize that no consensus exists about the definition and localization of the areas included in the urban-rural gradient. This prevents from comparing the results of different cities. A bibliography analysis has been conducted in order to 1) identify the different areas in the urban-rural gradient, the characteristics and types of characteristics used to define the most cited ones (i.e. urban, suburbs, sprawl, exurban, rurban, periurban and rural) ; 2) Through citation frequency indexes, evaluate the relative importance of characteristics and types of characteristics for every area and then for the whole gradient; 3) Evaluate the principal characteristics according to a series of criteria (the best characteristic is supposed to be quantitative, integrative, marking a consensus, discriminative and easy to apply on the field); 4) On the basis of retained characteristics, propose single and simple definitions to the most cited areas. These new definitions aim at enable areas identification on the field and on satellite images. These new definitions have been applied to the field study of the city of Lubumbashi (D.R.C) and seem to be convenient. Retained characteristics have then been translated into landscape composition indexes for the future study of the following cities on basis of satellite imagery, without field research. Indeed, such indexes are commonly used in landscape ecology because they allow the description of the urban landscape pattern or structure which, according to the central hypothesis of landscape ecology, i.e. “pattern-process paradigm”, influence landscape ecological processes. [less ▲]

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See detailPlant ecological niche distribution along heavy metal gradients
Boisson, Sylvain ULg; Monty, Arnaud ULg; Seleck, Maxime ULg et al

Conference (2013, June 26)

Why species do not occur everywhere? The concept of ecological niche is central to understand relationships among biotic/abiotic factors and species distribution. Gradients of environmental stress ... [more ▼]

Why species do not occur everywhere? The concept of ecological niche is central to understand relationships among biotic/abiotic factors and species distribution. Gradients of environmental stress associated to interspecific interactions generate testable patterns of specie’s response curves. Distribution of response curves have been seldom tested along toxicity gradient, in contrast to resource gradients. On Katangan copper hills (south R.D.C.), natural copper and cobalt concentrations span a large range: 2 - 1000 mg kg-1 for cobalt and 30 - 10 000 mg kg-1 for copper. In this study, we evaluate three hypotheses related to niche distributions and shapes along metal toxic gradients: (1) Species optima are uniformly distributed over copper-cobalt gradient. (2) Realized niche width varies in relation to the niche optimum along copper and cobalt gradient. (3) Absolute values of skewness coefficient are higher when plant species optima are in the extremes of cobalt gradient with a niche tails toward mesic conditions. Realized niches of 80 taxa were modeled with general additive models (GAM) using presence/absence data in 172 1m² plots. Niche optima, niche widths and skewness coefficients were estimated from species response curves. The three hypotheses were globally validated. Three groups of species were distinguished according to their optima position along metal gradient with packed optima on intermediate concentrations suggesting higher interspecific competition in low metal concentrations. Niche width increased with metal concentrations. Highest metal tolerant plant species had broader niches. Skewness coefficient was inversely related to niche optima positions. Our study demonstrates that species distribution pattern on toxicity gradient presents similarities with resource gradient. Broad realized amplitude of species adapted to high levels of copper cobalt concentrations suggests that fundamental niche of specialist metallophytes may be larger than expected. This should be further tested in controlled conditions in association to competition tests. [less ▲]

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See detailGradient urbain-rural de la ville de Lubumbashi: dynamique entre 2002 et 2009
Andre, Marie ULg; Bogaert, Jan ULg; Mahy, Grégory ULg et al

in Ernoult, Aude (Ed.) Dynamiques écologiques des paysages: de l'agricole à l'urbain (2013, June 12)

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See detailSpecies delimitation and diversification in the widespread tree genus Milicia (Moraceae)
Daïnou, Kasso ULg; Mahy, Grégory ULg; Duminil, Jérôme et al

Conference (2013, June)

The long generation time and large effective size of widespread forest tree species can result in slow evolutionary rate and incomplete lineage sorting, complicating species delimitation. We addressed ... [more ▼]

The long generation time and large effective size of widespread forest tree species can result in slow evolutionary rate and incomplete lineage sorting, complicating species delimitation. We addressed this issue with the African timber tree genus Milicia that comprises two morphologically similar and often confounded species: M. excelsa, widespread from West to East Africa, and M. regia, endemic to West Africa. We combined information from nuclear microsatellites (nSSRs), nuclear and plastid DNA sequences, and morphological systematics to identify significant evolutionary units and infer their evolutionary and biogeographical history. We detected five geographically coherent genetic clusters using nSSRs and three levels of genetic differentiation. First, one West African cluster matched perfectly with the morphospecies M. regia, which formed a monophyletic clade at both DNA sequences. Second, a West African M. excelsa cluster formed a monophyletic group at plastid DNA and was more related to M. regia than to Central African M. excelsa, but shared many haplotypes with the latter at nuclear DNA. Third, three Central African clusters appeared little differentiated and shared most of their haplotypes. Although gene tree paraphyly could suggest a single species in Milicia following the Phylogenetic Species Concept, the existence of mutual haplotypic exclusivity and non-admixed genetic clusters in the contact area of the two taxa indicate strong reproductive isolation, and thus, two species following the Biological Species Concept. Molecular dating of the first divergence events showed that speciation in Milicia is ancient (Tertiary), indicating that long-living tree taxa exhibiting genetic speciation may remain similar morphologically. [less ▲]

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See detailTrees communities and filters to restoration along a periurban gradient of tropical forest degradation
Hick, Aurélie ULg; Tooth, Martin; Tshibungu, Alain et al

Conference (2013, June)

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See detailIntegrated management of wild chamomile populations by tillage
Jaunard, Delphine ULg; Monty, Arnaud ULg; Mahy, Grégory ULg et al

in Agricultural and Apllied Biological Sciences (2013, May 21)

Gembloux, Belgium Chemical weeding in agriculture increasingly raises environmental, health and economic preoccupations. European authorities has set up legislations (directive 91/414, settlement 1107 ... [more ▼]

Gembloux, Belgium Chemical weeding in agriculture increasingly raises environmental, health and economic preoccupations. European authorities has set up legislations (directive 91/414, settlement 1107/2009, directive 2009/128) aiming to reduce risks related to the use of pesticides and encouraging integrated pest management. This situation leads professionals and scientists to take interest in the biology and population dynamics of weeds and to study the impacts of integrated pest management on weeds and crops. Tillage can potentially be an efficient weed control method in winter wheat (Triticum aestivum L.). We studied wild chamomile (Matricaria chamomilla L.) population dynamics and crop yields in an experimental winter wheat crop, in relation to tillage methods. Five modalities (i.e. different combinations of a stubble cultivator and/or a moldboard plow, including a no-tillage control) were applied during three years (2009-2012), with four replications, in Gembloux (Belgium). In each plot, M. chamomilla density was recorded throughout the seasons. In summer 2012, wild chamomile density was significantly lower in plots tilled with a moldboard plow. The use of a stubble cultivator did not significantly affect M. chamomilla density. In addition, we found higher wheat yields in ploughed plots, indicating that the decrease in M. chamomilla density reduced competition for wheat. To confirm these results, experiments are still under investigation in similar conditions. [less ▲]

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See detailA comparison of soil properties under four vegetation units from six metalliferous hills in Katanga
Kaya Muyumba, Donato ULg; Mahy, Grégory ULg; Ngongo Luhembwe, Michel et al

Conference (2013, April 12)

In Katanga (Democratic Republic of Congo), numerous metalliferous hills are distributed along what is called the copperhill belt from Kolwezi to Lubumbashi. Very specific vegetation developed on these ... [more ▼]

In Katanga (Democratic Republic of Congo), numerous metalliferous hills are distributed along what is called the copperhill belt from Kolwezi to Lubumbashi. Very specific vegetation developed on these hills within the miombo forest in response to very specific soil conditions, among which the copper content. Previous studies have already shown the existence of gradients of copper from the mineralized rocks outcropping at the top of the hills to the foot slopes on colluviums. After a characterization of the vertical variability of soil properties in pits distributed along the main slopes, we investigated the soil-vegetation relationships in six hills located between the towns of Tenke and Fungurume. Observation 1-square meter plots were installed in four vegetation units and sixty of them were selected according to their relative importance on the six hills. The soil from the top 10cm was sampled and analyzed for pH, Total Organic Carbon, available P, K, Mg, Ca, Cu, Co and Mn and soluble Cu and Co. Analysis of variance was performed in order to assess whether the effects of the “Hill” and of the “Vegetation Unit” were significant to explain soil chemical variability. Additionally, short transects were sampled at the boundaries from adjacent vegetation units in order to evaluate the gradual or rough nature of change in soil properties under these units. [less ▲]

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See detail3. Contrôle des populations de mauvaises herbes
Jaunard, Delphine ULg; Monty, Arnaud ULg; Mahy, Grégory ULg et al

in Bodson, Bernard; Destain, Jean-Pierre (Eds.) Livre Blanc - Céréales (2013, February 27)

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See detailImportance de la méthode de coupe sur la régénération de Combretaceae du Bassin arachidier sénégalais
Faye, E; Diallo, H; Samba, SAN et al

in Tropicultura (2013), 31(1), 44-52

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See detailApport de la surface terrière dans la dénomination des formations végétales dominées par le tapia (Uapaca bojeri) à Madagascar
Malaisse, François ULg; Rakotondrasoa, Olivia; Rakotoniaina, R.T. et al

in Verheggen, François; Bogaert, Jan; Haubruge, Eric (Eds.) Les vers à soie malgaches. Enjeux écologiques et socio-économiques. (2013)

Après avoir rappelé l’intérêt transcendant d’Uapaca bojeri, essence endémique malgache, pour les populations locales et avoir défini l’importance des apports écosystémiques des formations végétales où ... [more ▼]

Après avoir rappelé l’intérêt transcendant d’Uapaca bojeri, essence endémique malgache, pour les populations locales et avoir défini l’importance des apports écosystémiques des formations végétales où cette essence domine, la diversité des dénominations concernant ces dernières est mise en évidence et les causes sous-jacentes en sont analysées. Une situation analogue a été observée antérieurement pour les forêts claires de type miombo en Afrique continentale ; le concept de surface terrière a constitué pour ces dernières un apport pertinent et a autorisé une typologie valorisante des dénominations. Dès lors, l’application du concept de surface terrière aux formations végétales à dominance de tapia est examinée et son apport éventuel discuté. Un système original est proposé. [less ▲]

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See detailGuide to selected miombo species regeneration (Final version 2.2)
Seleck, Maxime ULg; Hick, Aurélie ULg; Ilunga wa Ilunga, Edouard et al

Report (2013)

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See detailWhy some species cannot colonize restored habitats? The effects of seed and microsite availability
Piqueray, Julien ULg; Saad, Layla; Bizoux, Jean-Philippe ULg et al

in Journal for Nature Conservation (2013), 21

Restoration of calcareous grasslands was promoted as a conservation strategy to reduce the risks imposed by habitat loss and fragmentation. Restoration already provided promising results for several taxa ... [more ▼]

Restoration of calcareous grasslands was promoted as a conservation strategy to reduce the risks imposed by habitat loss and fragmentation. Restoration already provided promising results for several taxa, however some specialist species still fail at colonizing restored habitats. We aimed at explaining this lack of colonization success for three calcareous grasslands specialist species in Southern Belgium: Pulsatilla vulgaris, Trifolium montanum and Veronica prostrata. We studied: (i) Germination in control and outdoor conditions (cold, heat, smoke and litter effects); (ii) In-situ seedling emergence patterns (effects of seed addition and germination microsites availability). The three species were able to germinate in Petri dishes in the absence of treatment. Cold enhanced the germination of V. prostrata. Fire-related treatments (heat shock and smoke exposure) did not enhance germination and were deleterious to V. prostrata. Litter cover improved P. vulgaris emergence in outdoor containers, but had a negative effect on V. prostrata. In the field, V. prostrata did not emerge. T. montanum seedlings were observed in the reference grasslands when seeds were added, but not in the restored grasslands. P. vulgaris emerged in the reference grasslands, and to a lower degree in the restored grasslands. The combination of seed addition and microsites availability for seed germination resulted in enhanced seedling emergence for P. vulgaris. Our results suggest that seed and microsite availability can be limiting factors for site colonization, but the combination of both is likely much more limiting. Lower seedling emergence in restored than in reference grasslands suggests a lower habitat quality in restored grasslands. [less ▲]

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See detailCompte-rendu et apport de la conférence-débat : « Nature, conditionnalité et verdissement de la PAC : un tournant wallon ? ». 9 novembre 2011. Espace Senghor, Gembloux, Belgique.
Piqueray, Julien ULg; Richard, Catherine ULg; Walot, Thierri et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17

Recently, the European Union (EU) proposed a reform project for the Common Agricultural Policy (CAP). One of the proposed reforms consists in imposing to set aside 7% of arable land for biodiversity ... [more ▼]

Recently, the European Union (EU) proposed a reform project for the Common Agricultural Policy (CAP). One of the proposed reforms consists in imposing to set aside 7% of arable land for biodiversity support purposes. About this proposal, a conference was hold in Gembloux, Belgium, on 9th November 2011. Such systems already exist in neighboring countries. French and Swiss systems were displayed in order to highlight their advantages and limits. Scientific arguments subtending such policies were presented. It was shown that creation of semi-natural elements in the agricultural matrix should be efficient to promote biodiversity. Both the quantity and the quality of these elements should be considered. Also, biodiversity is likely to provide services to agriculture, notably crop pollination and pest control. Currently, uncertainties remain on eligible areas to reach the 7% threshold. However, based on most probable scenarios, the current likely eligible areas cover only 4.3% of arable land in Wallonia. Less than 20% of Walloon farms already reach the 7% threshold proposed by the EU. If the European project is approved, it will therefore be of first importance to have a societal recognition toward farmers for their effort. To optimize positive effects of the policy on biodiversity, it is also imperative to make sure that a high biological quality is reached in the areas dedicated to biodiversity and to monitor this quality in the light of clearly defined objectives. Economical, societal and environmental issues should all be considered when applying this policy in order to improve agriculture sustainability and to stop biodiversity decline in agricultural landscapes. [less ▲]

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