References of "Bizoux, Jean-Philippe"
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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 detailRapid Plant Invasion in Distinct Climates Involves Different Sources of Phenotypic Variation
Monty, Arnaud ULg; Bizoux, Jean-Philippe ULg; Escarré, José et al

in PLoS ONE (2013), 8(1), 55627

When exotic species spread over novel environments, their phenotype will depend on a combination of different processes, including phenotypic plasticity (PP), local adaptation (LA), environmental maternal ... [more ▼]

When exotic species spread over novel environments, their phenotype will depend on a combination of different processes, including phenotypic plasticity (PP), local adaptation (LA), environmental maternal effects (EME) and genetic drift (GD). Few attempts have been made to simultaneously address the importance of those processes in plant invasion. The present study uses the well-documented invasion history of Senecio inaequidens (Asteraceae) in southern France, where it was introduced at a single wool-processing site. It gradually invaded the Mediterranean coast and the Pyrenean Mountains, which have noticeably different climates. We used seeds from Pyrenean and Mediterranean populations, as well as populations from the first introduction area, to explore the phenotypic variation related to climatic variation. A reciprocal sowing experiment was performed with gardens under Mediterranean and Pyrenean climates. We analyzed climatic phenotypic variation in germination, growth, reproduction, leaf physiology and survival. Genetic structure in the studied invasion area was characterized using AFLP. We found consistent genetic differentiation in growth traits but no home-site advantage, so weak support for LA to climate. In contrast, genetic differentiation showed a relationship with colonization history. PP in response to climate was observed for most traits, and it played an important role in leaf trait variation. EME mediated by seed mass influenced all but leaf traits in a Pyrenean climate. Heavier, earlier-germinating seeds produced larger individuals that produced more flower heads throughout the growing season. However, in the Mediterranean garden, seed mass only influenced the germination rate. The results show that phenotypic variation in response to climate depends on various ecological and evolutionary processes associated with geographical zone and life history traits. Seeing the relative importance of EME and GD, we argue that a “local adaptation vs. phenotypic plasticity” approach is therefore not sufficient to fully understand what shapes phenotypic variation and genetic architecture of invasive populations. [less ▲]

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See detailConservation and management of a threatened traditional agroresource, ylang-ylang Cananga odorata [Lam.] Hook f. & Thomson forma genuina, in the Indian Ocean islands
benini, céline; Mahy, Grégory ULg; jacquemin, jean-marie et al

in Crop Science (2012), 52(6), 2606-2618

In order to handle future economic, social and environmental changes, the assessment, management and conservation of the local genetic resources of cash crop species is a fundamental requirement. We ... [more ▼]

In order to handle future economic, social and environmental changes, the assessment, management and conservation of the local genetic resources of cash crop species is a fundamental requirement. We investigated the pattern of genetic and morphological diversity of Cananga odorata (Lam.) Hook f. & Thomson forma genuina, an important essential oil tree for the perfume industry in the introduction area of the western Indian Ocean islands. We sought to identify key elements for developing a conservation and management strategy for ylang-ylang genetic resources. Genetic and morphological variations were assessed using Amplified Fragments Length Polymorphism and morphometrics traits and information about farmers' practices were collected. The existence of substantial overall genetic diversity (HT = 0.2599) and the grouping of plantations into different genetic groups suggest that there have been a series of introduction events in the area, with limited exchanges of genetic material within and between islands, which is not what is suggested in the historical records. The morphological study revealed high phenotypic variability despite very similar agronomical practices throughout the studied area. The morphological and genetic variability might have been created and maintained without any planned or conscious management, and this has largely determined the genetic structuring in the area (11.74% genetic variation among islands and 20.68% among plantations). With this species, where past introduction events and farmers’ practices have shaped the genetic variation, on-farm preservation and the maintenance of the current management practices is recommended. Ex situ conservation efforts should also be undertaken, if economically affordable. [less ▲]

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See detailComparative Chemical and Molecular Variability of Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Ylang-Ylang) in the Western Indian Ocean Islands: Implication for Valorization
Benini, Céline ULg; Mahy, Grégory ULg; Bizoux, Jean-Philippe ULg et al

in Chemistry & Biodiversity (2012), 9(7), 13891402

Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite ... [more ▼]

Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite its economic and social importance, very little information is available on its variability and the possible factors causing it. Therefore, the relationship between the genetic structure, revealed by amplified fragment length polymorphism (AFLP), and the essential oil chemical composition, determined by GC/MS analysis, of ylang-ylang grown in semi-managed systems in three Indian Ocean islands (Grande Comore, Mayotte, and Madagascar) was investigated. Our results revealed a low genetic variation within plantations and contrasted situations between islands. Variations of the chemical composition could be observed within plantations and between islands. The genetic differentiation pattern did not match the observed pattern of chemical variability. Hence, the chemical variation could not be attributed to a genetic control. As Grande Comore, Madagascar, and Mayotte present different environmental and agronomic conditions, it can be concluded that the influence of these conditions on the ylang-ylang essential oil composition is consistent with the patterns observed. Finally, several strategies were proposed to valorize the chemical composition variations. [less ▲]

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See detailEffects of management regimes and extreme climatic events on plant population viability in Eryngium alpinum
Andrello, Marco; Bizoux, Jean-Philippe ULg; BARBET-MASSIN, morgane et al

in Biological Conservation (2012), 147(1), 99-106

Extreme climatic events like the 2003 summer heatwave and inappropriate land management can threaten the existence of rare plants. We studied the response of Eryngium alpinum, a vulnerable species, to ... [more ▼]

Extreme climatic events like the 2003 summer heatwave and inappropriate land management can threaten the existence of rare plants. We studied the response of Eryngium alpinum, a vulnerable species, to this extreme climatic event and different agricultural practices. A demographic study was conducted in seven field sites between 2001 and 2010. Stage-specific vital rates were used to parameterize matrix population models and perform stochastic projections to calculate population growth rates and estimate extinction probabilities. Among management regimes, spring grazing and land abandonment decreased vital rates and population growth, while autumn grazing and late mowing had positive effects on population viability. The 2003 heatwave reduced fecundity rates and survival rates. Only spring grazed sites presented considerable extinction risk. Stochastic projections showed that an increased frequency of 2003-like events may exacerbate extinction risk, but extinction probability depends mainly on land management regimes. To better conserve E. alpinum populations, we recommend conversion of presently spring grazed and abandoned sites to late mowing or autumn grazing. [less ▲]

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See detailEffect of the 2003 heatwave on Eryngium alpinum demography under different management regimes
Bizoux, Jean-Philippe ULg; Andrello, Marco; Till-Bottraud, Irène

Conference (2011, September 28)

In the summer of 2003, Europe was impacted by an extreme heatwave that altered ecosystem productivity and increased plant mortality in natural areas. We analyse the effect of this extreme climatic event ... [more ▼]

In the summer of 2003, Europe was impacted by an extreme heatwave that altered ecosystem productivity and increased plant mortality in natural areas. We analyse the effect of this extreme climatic event on the demography of the protected alpine plant Eryngium alpinum in relation to local ecological conditions and management regimes (mowing, grazing and unmanaged). Spatiotemporal variation in the vital rates of different plant life-stages (seedlings, juveniles, vegetative and reproductive adults) was estimated in seven sites of E. alpinum in the French Alps between 2001 and 2010. The effects on population dynamics (deterministic and stochastic population growth rates, λ and a) were studied using matrix population models and life table response experiments. Reductions in survival rates were observed following the extreme 2003 summer. λ was smaller during the heatwave and a decreased in simulations where the occurrence probability of a 2003-like event was increased. Adult survival rates and fecundity were negatively affected by heavy spring grazing, leading to lower λ and a. There were few differences in population dynamics between mowed and unmanaged sites. While greater rates of heatwave occurrence did increase extinction probability, only heavily grazed sites showed considerable extinction risk. As a consequence, heavy spring grazing must be discouraged in sites where the conservation of E. alpinum is a priority, while it is important to quantify acceptable levels of grazing in semi-natural areas where plant conservation has to be achieved in accordance with human development needs. [less ▲]

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See detailImpact of population history on Viola calaminaria conservation, an endemic species of calamine sites
Bizoux, Jean-Philippe ULg; Mahy, Grégory ULg

Conference (2011, June)

The zinc violet, Viola calaminaria is a threatened species, endemic to calamine sites in Belgium and West Germany. Since the end of 19th century, the V. calaminaria habitat network have exhibited a huge ... [more ▼]

The zinc violet, Viola calaminaria is a threatened species, endemic to calamine sites in Belgium and West Germany. Since the end of 19th century, the V. calaminaria habitat network have exhibited a huge dynamics, with creation of new habitats resulting from industrial pollution and destruction of habitats by urbanisation and site remediation. In the present study, we analysed the effect of population history (recent/ancient population) on genetic diversity, fitness and reproductive success in order to discuss conservation strategies for the species. Recently founded populations exhibited similar level of genetic diversity (Hs) as ancient populations but showed a lower genetic differentiation among population (Fst). No indication of strong founder effects in recently established populations was detected. Plant fitness (seed set and germination percentage) was higher in recent populations while other reproductive traits (vegetative density, flower density, fructification percentage) did not differ according to population history. Results suggest that the creation of habitats through human activities can provide new opportunities for conservation of this species. In increasingly disturbed environments, this indicates that, at least for some species, conservation strategies should not focus solely on traditional and natural habitats but also consider the potential benefits offered by modified landscapes. [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 (2011, June)

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 refl ect 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 detailDynamics of black-grass populations depending on the sowing time of winter wheat
Vandersteen, Joëlle; Jaunard, Delphine ULg; Mahy, Grégory ULg et al

in Communications in Agricultural and Applied Biological Sciences (2011, May 24), 76(3), 485-490

Currently, economic, agronomic and environmental concerns, lead to reduce use of herbicides. This reduction can be help by cultural measures like delay of the sowing date. Four sowing dates of winter ... [more ▼]

Currently, economic, agronomic and environmental concerns, lead to reduce use of herbicides. This reduction can be help by cultural measures like delay of the sowing date. Four sowing dates of winter wheat from 15th of October to 26th of November were tested. Dynamic of black-grass populations and their reproduction rate were assessed as well as dynamic of winter wheat for each date. Delay of sowing could significantly reduce reproduction rate of blac-grass. It was shwn that the emergence rate (pl/m²), but also number of ears per plant and number of seeds per ear of black-grass decreased significantly with the sowing date. This reproduction of seeds productioin already is from sixty per cent of a delay of two weeks sowing. [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 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 ▲]

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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 detailTaxa distribution and RAPD markers indicate different origin and regional differentiation of hybrids in the invasive Fallopia complex in central-western Europe
Krebs, C.; Mahy, Grégory ULg; Matthies, D. et al

in Plant Biology (2010), 12(1), 215-223

Interspecific hybridization can be a driving force for evolutionary processes during plant invasions, by increasing genetic variation and creating novel gene combinations, thereby promoting genetic ... [more ▼]

Interspecific hybridization can be a driving force for evolutionary processes during plant invasions, by increasing genetic variation and creating novel gene combinations, thereby promoting genetic differentiation among populations of invasive species in the introduced range. We examined regional genetic structure in the invasive Fallopia complex, consisting of F. japonica var. japonica, F. sachalinensis and their hybrid F. × bohemica, in seven regions in Germany and Switzerland using RAPD analysis and flow cytometry. All individuals identified as F. japonica var. japonica had the same RAPD phenotype, while F. sachalinensis (11 RAPD phenotypes for 11 sampled individuals) and F. × bohemica (24 RAPD phenotypes for 32 sampled individuals) showed high genotypic diversity. Bayesian cluster analysis revealed three distinct genetic clusters. The majority of F. × bohemica individuals were assigned to a unique genetic cluster that differed from those of the parental species, while the other F. × bohemica individuals had different degrees of admixture to the three genetic clusters. At the regional scale, the occurrence of male-fertile F. sachalinensis coincided with the distribution of F. × bohemica plants showing a high percentage of assignment to both parental species, suggesting that they originated from hybridization between the parental species. In contrast, in regions where male-fertile F. sachalinensis were absent, F. × bohemica belonged to the non-admixed genetic group, indicating multiple introductions of hybrids or sexual reproduction among hybrids. We also found regional differentiation in the gene pool of F. × bohemica, with individuals within the same region more similar to each other than to individuals from different regions. [less ▲]

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