References of "Piqueray, Julien"
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See detailChemical soil factors influencing plant assemblages along copper-cobalt gradients: implications for conservation and restoration
Seleck, Maxime ULg; Bizoux, Jean-Philippe ULg; Colinet, Gilles ULg et al

in Plant and Soil (2013), 373

Aims Define the chemical factors structuring plant communities of three copper-cobalt outcrops (Tenke-Fungurume, Katangan Copperbelt, D. R. Congo) presenting extreme gradients. Methods To discriminate ... [more ▼]

Aims Define the chemical factors structuring plant communities of three copper-cobalt outcrops (Tenke-Fungurume, Katangan Copperbelt, D. R. Congo) presenting extreme gradients. Methods To discriminate plant communities, 172 vegetation records of all species percentage cover were classified based on NMDS and the Calinski criterion. Soil samples were analyzed for 13 chemical factors and means compared among communities with ANOVA. Partial canonical correspondence analysis (pCCA) was used to determine amount of variation explained individually by each factor and site effect. Results Seven communities were identified. Six of the studied communities were related to distinct sites. Site effect (6.0 % of global inertia) was identified as the most important factor related to plant communities’ variation followed by Cu (5.5 %), pH (3.6 %) and Co (3.5 %). Unique contribution of site effect (3.8 %) was higher than that of Cu (1.1 %) and Co (1.0 %). Conclusions In restoration, not only Cu and Co contents will be important to maintain vegetation diversity, attention should also be given to co-varying factors potentially limiting toxicity of metals: pH, organic matter, Ca and Mn. Physical parameters were also identified as important in the creation of adequate conditions for diverse communities. Further studies should focus on the effect of physical parameters and geology. [less ▲]

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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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See detailWanted ! Avez-vous vu ces plantes ? La conservation des plantes messicoles dans le cadre du Programme Agroenvironnemental wallon
Piqueray, Julien ULg; Gilliaux, Valentin ULg; Mahy, Grégory ULg

E-print/Working paper (2012)

Afin de mener à bien un projet de conservation des plantes messicoles menacées, la Faculté AgroBioTech de Gembloux appelle à diffuser vos observations de terrain au DEMNA

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See detailDes bleuets et autres plantes messicoles dans les champs… presque comme autrefois
Piqueray, Julien ULg; Gilliaux, Valentin ULg; Mahy, Grégory ULg

Article for general public (2012)

Grâce à une poignée d’agriculteurs et avec l’aide de mesures axées sur la préservation de la biodiversité dans le cadre du programme agro-environnemental mis en oeuvre en Wallonie, bleuets, coquelicots ... [more ▼]

Grâce à une poignée d’agriculteurs et avec l’aide de mesures axées sur la préservation de la biodiversité dans le cadre du programme agro-environnemental mis en oeuvre en Wallonie, bleuets, coquelicots, chrysanthèmes des moissons... ces fleurs des champs menacées, compagnes des céréales, trouvent un asile, moyennant une compensation financière. [less ▲]

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

Conference (2011, June 13)

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 detailConservation of an endemic metallophyte species: effect of population history and vegetative density on the reproductive success of Viola calaminaria
Bizoux, Jean-Philippe ULg; cristofoli, sara; Piqueray, Julien ULg et al

in Journal for Nature Conservation (2011), 19

Demographic studies that monitor population dynamics are an essential component in establishing conservation strategies. The conventional view that human disturbance results in negative effects to species ... [more ▼]

Demographic studies that monitor population dynamics are an essential component in establishing conservation strategies. The conventional view that human disturbance results in negative effects to species and habitats is countered by the fact that some anthropogenic activities result in the origin of new habitat opportunities for species. Faced with an increase in European restoration programs, studies that assess the variability in traits conferring reproductive success among populations is particularly relevant to rare species conservation and further improves our knowledge to achieve restoration success. In the present study, we evaluated reproductive success variation (flower density, percent fructification and seed set) in Viola calaminaria, a rare endemic metallophyte, in relationship to population origins (ancestral or recent habitat), plant density and habitat structure. Results indicated that seed set varied significantly among ancestral and recently established populations, with recent populations exhibiting increased seed set (P < 0.05). Habitat structure did not influence species reproductive success. A positive significant correlation was detected between vegetative and flower density (P < 0.001). Results suggested that population origin (ancestral or recent) and local vegetative density was more important than habitat structure on reproductive success in V. calaminaria. In addition, we demonstrated that V. calaminaria populations distributed in habitats recently created by anthropogenic activity exhibited similar or higher reproductive success than populations from ancestral sites. These results are noteworthy as they show that anthropogenic activities can create new favourable habitats for some rare species. [less ▲]

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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)

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See detailLe statut du brome épais (Bromus grossus) en Région Wallonne
Delescaille, Louis-Marie; Piqueray, Julien ULg; Godefroid, Sandrine

in Adoxa (2011), 69-70

Le brome épais (Bromus grossus Desf. ex DC.) est une graminée commensale des moissons bien qu'on la trouve occasionnellement en bordure de champs ou dans des terrains en friche. C'est une espèce menacée ... [more ▼]

Le brome épais (Bromus grossus Desf. ex DC.) est une graminée commensale des moissons bien qu'on la trouve occasionnellement en bordure de champs ou dans des terrains en friche. C'est une espèce menacée de disparition dans toute son aire de répartition, raison qui a justifié son inscription à l'annexe II de la Directive 92/43/CEE du Conseil du 21 mai 1992 concernant la conservation des habitats naturels ainsi que de la faune et de la flore sauvages (aussi connue comme la "Directive Habitats"). Cette protection est assurée au niveau wallon par l'inscription de l'espèce à l'annexe VIa du décret du Gouvernement Wallon du 6/12/2001 ; en raison de sa très grande rareté, la Région Wallonne a une responsabilité importante pour sa conservation. [less ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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