121 results on '"Grégory Mahy"'
Search Results
2. Success of passive and active restoration of lowland hay meadows with regard to current and historical references
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Maïké Dellicour, Thibaut Goret, Julien Piqueray, Adeline Fayolle, Jérôme Bindelle, and Grégory Mahy
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grassland ,restoration success ,diaspore transfer ,restoration reference ,plant community ,hay transfer ,Evolution ,QH359-425 ,Ecology ,QH540-549.5 - Abstract
The restoration of hay meadows is one of the major challenges in temperate Europe, to overcome the drastic loss and degradation of these semi-natural habitats. Evaluation of restoration success requires the definition of a relevant reference ecosystem. Historical phytosociological relevés dating from the 1960s–1970s, before large scale agriculture intensification, may be used as the reference framework for such purposes. However, this reference framework may no longer be pertinent in our present-day ecological and socio-economic context. In this study, we assessed the success of three restoration techniques for lowland hay meadows, based on plant species richness and composition and functional traits, by comparing the restoration trajectories to historical and current references. The three restoration techniques, passive restoration mowing, active fresh hay transfer and active sowing of threshing material, were implemented depending on the initial level of degradation and the proximity to well-preserved meadows. The species composition of restored meadows clearly differed from historical references but converged toward current references, for both passive and active restoration techniques. Historical references are characterized by short, stress-tolerant dicotyledonous plant species with small specific leaf area, indicators of nutrient-poor environments. The gap observed between plant communities of historical and current meadows suggests that the historical data are an over-ambitious target for restoration purposes and can hardly be considered relevant to our present-day context. Therefore, creation of a new reference framework of lowland hay meadows is needed for the adequate implementation of restoration projects. Successful outcomes of active and passive techniques must encourage practitioners to adapt the choice of the restoration method depending on the local ecological context, i.e., level of degradation and proximity to well-preserved habitats. more...
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- 2023
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3. The contribution of seedbank to the green roof plant community dynamics analogous to semi-natural grasslands
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Lucie Rivière, Alizé Sellier, Thierry Dutoit, Christel Vidaller, Elise Buisson, and Grégory Mahy
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plant dynamic ,ruderal ,spontaneous species ,green infrastructure ,seed persistence ,urban ecology ,Evolution ,QH359-425 ,Ecology ,QH540-549.5 - Abstract
Extensive green roofs have been shown to support native biodiversity and plant communities that are analogous to natural or semi-natural habitats such as grasslands. However, little is known about the role of soil seedbanks in the dynamic of extensive green roof plant communities. The purpose of this study was to analyze the seedbank that developed after 4 years of an extensive green roof analog to dry grassland plant community, seeded with 29 species. We aimed to understand the contribution of seedbank to the resilience of vegetation to harsh conditions of the roof and to colonization by surrounding spontaneous species. We monitored the plant species cover in 36 plots during 4 years in June (between 2018 and 2021), and sampled the seedbank in February 2021. Our results showed that the soil seedbank was dominated by transient spontaneous ruderals species, while the standing vegetation was still dominated by seeded grassland species. We found that seeded grassland species had poor seedbank stock, similar to their natural environments. The similarity index between the standing vegetation and the seedbank increased over time, and we measured a significant correlation between dominant species cover and their seedbank density. Spontaneous species cover was not correlated to the proportion of soil not colonized by seeded species cover, indicating that gaps in vegetation did not influence the development of spontaneous species. Our findings highlight the importance of seedbank in the dynamic of green roof vegetation and demonstrate that analogous habitat species exhibit similar behavior as in their natural environments. more...
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- 2023
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4. Coexistence and Succession of Spontaneous and Planted Vegetation on Extensive Mediterranean Green Roofs: Impacts on Soil, Seed Banks, and Mesofauna
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Christel Vidaller, Anaïs Jouet, Carmen Van Mechelen, Tania De Almeida, Jérôme Cortet, Lucie Rivière, Grégory Mahy, Martin Hermy, and Thierry Dutoit
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geophytes ,grassland species ,insolation ,local species ,plant cover ,plant diversity ,Agriculture - Abstract
Extensive green roofs are well known to improve the urban environment, but in the Mediterranean regions, dry climatic conditions pose the problem of their sustainability when no irrigation is applied. After planting or sowing in 2012, 18 local Mediterranean plant species on different types of exposure and substrate in a non-irrigated extensive green roof in Avignon (South-Eastern France), the physico-chemical characteristics of the soil, winter and spring soil seed banks, soil mesofauna and initially sown, planted, or spontaneous vegetation expressed on the surface were studied from 2013 to 2020. In 2020, significant differences related to the exposure conditions (shade/sun) and, to a lesser extent, to the depth of substrate used (5 cm/5 cm or 10 cm with a water retention layer) were found. The deeper plots in the shade have significantly higher soil fertility, cover, and vegetation height. However, the plots in the sun have higher moss cover, planted or sowed vegetation abundance, and springtail abundance. By 2020, more than half of the initially sown species had disappeared, except for several planted perennials and short-cycle annual species. On the other hand, a significant increase in the species richness of spontaneously established species was measured over time. In the absence of a permanent and transient seed bank for the sowed and spontaneous species, the plant community is then mostly dependent on species flows via the local surrounding seed rain. Planting perennial species (Sedum spp., Iris lutescens), followed by spontaneous colonization of species present in the vicinity of the roof would then represent a more efficient strategy for the persistence of extensive non-irrigated green roofs in Mediterranean environments than sowing a species-rich local Mediterranean seed mixture dominated by annual species. more...
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- 2023
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5. Autumn sowing and first-year mowing enhance flowering species abundance and diversity in wildflower strips
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Julien Piqueray, Valentin Gilliaux, Bernard Bodson, and Grégory Mahy
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agri-environmental scheme ,wildflower strip ,sowing date ,vegetation cutting ,first year management ,belgium ,Biotechnology ,TP248.13-248.65 ,Environmental sciences ,GE1-350 - Abstract
Description of the subject. Wildflower strips are used to provide flower resources for insects in agroecosystems. There is a need to determine implementation processes that maximize the development of the sown flowering species. Objectives. To determine the effect of i) sowing period (autumn and spring) and ii) early cutting of annuals during the first growing season on the development of the sown perennial species. Method. We surveyed species development during three years (2012-2014) in 24 plots in an experimental wildflower strip. Plots were sown either in autumn or in spring, and received or not an early cutting management in 2012. Results. Sown species were favored by autumn sowing. A few species did better after spring sowing. Two years later (2014), early cutting management enhanced sown flowering species abundance and diversity in case of spring sowing only. Conclusions. Studying implementation and management protocols is of first importance to improve the efficiency of wildflower strips. We recommend autumn sowing as a first approach, and mowing aimed at controlling annuals in the first year after sowing. more...
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- 2021
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6. Arboreta reveal the invasive potential of several conifer species in the temperate forests of western Europe
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Aurore Fanal, Grégory Mahy, Adeline Fayolle, and Arnaud Monty
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Biology (General) ,QH301-705.5 - Abstract
Identifying emerging invasive species is a priority to implement early preventive and control actions. In terms of the number of invasive tree species, forestry represents the second largest pathway of introduction, with an invasive debt likely existing for alien conifers in Europe. In the early 1900s, a network of arboreta was established in southern Belgium to assess the wood production potential of prospective conifer and broadleaved species. Here, we use eight arboreta as natural experiments to identify alien conifers presenting invasive behavior. Through systematic sampling, we quantified the natural regeneration of alien conifers and recorded local environmental variables. For each species, regeneration density, dispersal distances, and age structure were analyzed. Generalized mixed effects models were fitted to test the effect of planted area and tree-stand type on regeneration. The environmental space occupied by regenerating alien conifers was evaluated using principal component analysis. Out of 31 planted alien species, 15 (48%) were identified in natural regeneration, of which eight (26%) exhibited important regeneration density and dispersal distances. The most invasive species were Tsuga heterophylla and Abies grandis, confirming earlier field observations. Both large planted areas and areas planted with alien conifer species increased the density of regeneration. Species that had the highest regeneration density tolerated a wide range of environmental conditions, including shaded understory, which could lead to the invasion of mature, undisturbed forests. This study showed that 17% of the studied alien conifers are potentially invasive because they show important regeneration, long-distance dispersal, and, of importance, have already produced offspring that have matured and are capable of creating new satellite populations. In conclusion, our results provide a guideline for future planting operations, recommending extreme caution when planting these species in the temperate forests of Western Europe. more...
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- 2021
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7. Loss of pollinator specialization revealed by historical opportunistic data: Insights from network-based analysis.
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Floriane Jacquemin, Cyrille Violle, François Munoz, Grégory Mahy, Pierre Rasmont, Stuart P M Roberts, Sarah Vray, and Marc Dufrêne
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Medicine ,Science - Abstract
We are currently facing a large decline in bee populations worldwide. Who are the winners and losers? Generalist bee species, notably those able to shift their diet to new or alternative floral resources, are expected to be among the least vulnerable to environmental change. However, studies of interactions between bees and plants over large temporal and geographical scales are limited by a lack of historical records. Here, we used a unique opportunistic century-old countrywide database of bee specimens collected on plants to track changes in the plant-bee interaction network over time. In each historical period considered, and using a network-based modularity analysis, we identified some major groups of species interacting more with each other than with other species (i.e. modules). These modules were related to coherent functional groups thanks to an a posteriory trait-based analysis. We then compared over time the ecological specialization of bees in the network by computing their degree of interaction within and between modules. "True" specialist species (or peripheral species) are involved in few interactions both inside and between modules. We found a global loss of specialist species and specialist strategies. This means that bee species observed in each period tended to use more diverse floral resources from different ecological groups over time, highly specialist species tending to enter/leave the network. Considering the role and functional traits of species in the network, combined with a long-term time series, provides a new perspective for the study of species specialization. more...
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- 2020
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8. The influence of ecological infrastructures adjacent to crops on their carabid assemblages in intensive agroecosystems
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Emilie Pecheur, Julien Piqueray, Arnaud Monty, Marc Dufrêne, and Grégory Mahy
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Intensive agroecosystems ,Ecosystem services ,Agri-environment schemes ,Carabids ,Functional diversity ,Biodiversity ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Background Conserving biodiversity and enhancing ecosystem services of interest in intensive agroecosystems is a major challenge. Perennial ecological infrastructures (EIs), such as hedges and grassy strips, and annual EI under Agri-Environment Schemes appear to be good candidates to promote both. Our study focused on carabids, an indicator group responding both at the species and functional trait level to disturbances and supporting pest control and weed seed consumption services. Methods We compared carabid assemblages at the species and functional traits levels, sampled via pitfall trapping, in three types of EIs (hedges, grassy strips and annual flower strips) and crops. We also tested via GLMs the effect of (1) the type of EI at the crops’ border and (2) the distance from the crops’ border (two meters or 30 meters) on carabid assemblages of crops. Tested variables comprised: activity-density, species richness, functional dispersion metrics (FDis) and proportions of carabids by functional categories (Diet: generalist predators/specialist predators/seed-eaters; Size: small/medium/large/very large; Breeding period: spring/autumn). Results and Discussion Carabid assemblages on the Principal Coordinate Analysis split in two groups: crops and EIs. Assemblages from all sampled EIs were dominated by mobile generalist predator species from open-land, reproducing in spring. Assemblages of hedges were poor in activity-density and species richness, contrarily to grassy and annual flower strips. Differences in carabid assemblages in crops were mainly driven by the presence of hedges. The presence of hedges diminished the Community Weighted Mean size of carabids in crops, due to an increased proportion of small ( more...
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- 2020
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9. Drought stress inducing intraspecific variability in Potentilla tabernaemontani (Rosaceae), a calcareous grassland species
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Mélanie Harzé, Grégory Mahy, and Arnaud Monty
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intraspecific variability ,calcareous grasslands ,Plant ecology ,QK900-989 - Abstract
Background and aims – Calcareous grasslands are among the most species-rich habitats in Western Europe. Populations of plant species characterizing these ecosystems are naturally submitted to high variability in environmental conditions at the very local scale, resulting in pronounced variation in functional traits. Individuals located on xeric parts of calcareous grasslands are characterized by plant traits that potentially ensure more successful performance under stressful conditions. In the context of increased frequency of summer heat waves based on climate change, our aim was to determine a possible intraspecific variability in drought response among individuals of one calcareous grassland plant species.Methods – A greenhouse experiment was set up to follow survival of Potentilla tabernaemontani Asch. individuals according to their habitat of origin (xeric or mesic parts of Belgian calcareous grasslands) and the treatment applied (low or high drought stress).Key results – The results demonstrated that individuals originating from xeric parts survived drought stress better than individuals from mesic parts of calcareous grasslands. Specific leaf area (SLA) of all individuals was very low in the experiment, allowing them to decrease water loss during drought stress. Leaf production was lower for individuals exposed to high drought stress while flower production was higher. That potentially expressed a trade-off between tolerance to water stress, individual growth and reproduction. Conclusions – Local scale environmental heterogeneity deserves to be considered in conservation and restoration plans as it induces intraspecific functional variability between individuals and impacts individuals’ ability to survive drought stress. more...
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- 2018
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10. Rapid plant invasion in distinct climates involves different sources of phenotypic variation.
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Arnaud Monty, Jean-Philippe Bizoux, José Escarré, and Grégory Mahy
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Medicine ,Science - Abstract
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. more...
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- 2013
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11. Fast height growth is key to non-native conifers invasiveness in temperate forests
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Aurore, Fanal, primary, Annabel, Porté, additional, Grégory, Mahy, additional, and Arnaud, Monty, additional
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- 2023
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12. Do plant traits help to design green walls for urban air pollution control? A short review of scientific evidences and knowledge gaps
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Anaïs Hellebaut, Sylvain Boisson, and Grégory Mahy
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Plant Leaves ,Air Pollutants ,Air Pollution ,Health, Toxicology and Mutagenesis ,Environmental Chemistry ,Particulate Matter ,General Medicine ,Plants ,Pollution ,Environmental Monitoring ,Trees - Abstract
It is often claimed that green walls (GW) and living wall systems (LWS) have a positive effect on urban air pollution problems if their plants composition is optimal (design of the LWS). An in-depth review of the knowledge on plants traits maximizing GW effects on air pollution shows that these might be hasty conclusions: there are still some important knowledge gaps. Robust conclusions can only be drawn for particulate matter (PM): the other pollutants are not analyzed by a sufficient number of studies. It can be concluded that leaves with hairs/trichomes are the most effective to capture PM. The rougher and the smaller the leaf is, the more PM it catches. The analysis of the plant composition of six LWS in Belgium indicated that these LWS supported a plant community dominated by only a few species, which do not exhibit in majority the most effective traits to maximize their PM capture. Regarding climbing plants, only three out of seven commonly used creepers in Belgium present hairs/trichomes on their leaves. Studies conducted on other pollutants and other traits are required to optimize the GW plant composition and to maximize their effects on air quality. more...
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- 2022
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13. Fast height growth is key to non-native conifers invasiveness in temperate forests.
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Aurore, Fanal, Annabel, Porté, Grégory, Mahy, and Arnaud, Monty
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Many exotic conifer species have been introduced for wood production in temperate regions. Some of these species can display an invasive behavior and negatively impact native ecosystems. It is therefore crucial to identify potentially invasive species before they are widely planted. Seedling high relative growth rate (RGR) and specific leaf area (SLA) have been associated with enhanced invasiveness of trees in previous studies. However, it has been mainly demonstrated for light-demanding species in disturbed habitats, less for shade-tolerant species in closed forests. Here, we investigated the link between seedlings growth traits of 15 exotic conifer species and invasiveness considered at both global and local scale. Seedlings were grown outdoor, under a shade net, and harvested after 4 and 10 weeks. RGR, SLA, Shoot–Root ratio, shoot relative growth rate, relative height growth rate (RHGR) and relative needles production rate were measured. We developed a continuous approach to position each species along a gradient of invasiveness. Local invasiveness consists of a value based on regeneration densities and dispersal distances observed in forest arboreta in Southern Belgium, and is therefore related to the ability of species to invade closed forest ecosystems. Global invasiveness was calculated based on the GBIF Database and the Global Compendium of Weeds, and encompasses all potentially invaded habitats. It appeared that RHGR was positively related to both local and global invasiveness, while SLA was positively related to local invasiveness only. However, RGR was not significantly related with local nor global invasiveness. This study indicates that preferential investment in rapid vertical growth associated with fast resource acquisition is a strategy enhancing invasiveness of non-native conifers, also in closed, shaded temperate forests. [ABSTRACT FROM AUTHOR] more...
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- 2024
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14. Can we foresee future maple invasions? A comparative study of performance-related traits and invasiveness of eight Acer species
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Aurore Fanal, Grégory Mahy, and Arnaud Monty
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Ecology ,Plant Science - Published
- 2022
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15. Interspecific trait integration increases with environmental harshness: A case study along a metal toxicity gradient
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Pierre Jacques Meerts, Edouard Ilunga wa Ilunga, Grégory Mahy, David Bauman, Maxime Seleck, and Guillaume Delhaye
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Ecologie ,Biologie du sol (relations sol plantes) ,metal tolerance ,species coexistence ,Ecology ,leaf economics spectrum ,Interspecific competition ,Biology ,functional diversity ,trait multidimensionality ,toxicity gradient ,Functional diversity ,Harshness ,Toxicity ,Trait ,community assembly ,Ecologie [végétale] ,Biologie spatiale ,Botanique générale ,functional trait coordination ,Ecology, Evolution, Behavior and Systematics - Abstract
Functional traits are commonly used to calculate a wide array of functional diversity indices to infer different mechanisms of community assembly and species coexistence. Recently, the degree of interspecific covariation between multiple functional traits has been suggested as a mechanism influencing both species distributions and abundances in communities. However, empirical assessments of this theory along environmental gradients are still scarce due to the lack of an appropriate method and of sufficiently strong environmental gradients. Here we compare interspecific trait integration (ITI) across plant communities along a marked gradient of copper toxicity in the soil, using new multivariate and bivariate indices. This was achieved using the range of the eigenvalues of a principal component analysis on the traits of the species in a local community (multivariate ITI index) and the correlations between traits in local communities (bivariate ITI index). We show that the plant metal tolerance strategy (i.e. leaf metal content) is relatively independent from leaf economics, while negatively correlated to plant size. In addition, our results indicate a weak support for the expected general patterns of trait syndromes, such as the ‘leaf economics spectrum’ or the ‘leaf–height–seed’, at the whole-community scale. This arises from an increase in multivariate trait integration along the soil copper gradient. The strongest trait integration is caused by an increase in the degree of association between certain traits on metal-rich soils. The multivariate trait integration explains species richness better than other commonly used functional diversity indices. Our study highlights the power of ITI, as well as its complementarity to other functional diversity indices, to investigate the variation in functional strategies and their drivers along environmental gradients. The increase in trait integration with soil metal toxicity in plant communities supports that highly constraining environments select increasingly coordinated sets of functional traits, in turn possibly driving the decrease in species richness. Further studies should assess the generality and underlying physiological mechanisms of such ecological patterns., SCOPUS: ar.j, info:eu-repo/semantics/published more...
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- 2020
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16. Comparison of mining spoils to determine the best substrate for rehabilitating limestone quarries by favoring native grassland species over invasive plants
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Roel Uyttenbroeck, Arnaud Monty, Grégory Mahy, Carline Pitz, and Mélanie Harzé
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geography ,Environmental Engineering ,geography.geographical_feature_category ,Calcareous grassland ,Biodiversity ,food and beverages ,Introduced species ,04 agricultural and veterinary sciences ,Vegetation ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Native plant ,01 natural sciences ,Grassland ,Invasive species ,Agronomy ,Habitat ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Environmental science ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
Habitats being restored in Belgian quarries are easily invaded by non-native plant species, which can hamper the germination and development of vegetation deemed to be of high conservation value. Substrates of terraces created when mining limestone quarries could be inhospitable to native plants. However, they can provide opportunities for establishing specific vegetation, such as dry calcareous grasslands. Applying suitable mining spoils could be a cost-effective way to provide growing substrate when restoring limestone terraces. We assessed the efficacy of using mining spoils, collected on-site, as a potential growing substrate (bedding material). We tested gravely limestone (product of on-site mining activities), limestone dust (by-product), and no addition (bare limestone bedrock) to determine which was best for favoring the growth of native, dry calcareous grassland species and discourage the growth of two non-native invasive species that commonly invade altered mining sites: Buddleja davidii Franch and Senecio inaequidens DC. In a field experiment (in two quarries), we studied short-term (2 y) growth response of native and invasive species after sowing three seed mixtures of native grassland species, varying in functional diversity (and one no-sowing control treatment), all treatments subjected to competitive pressure exerted by invasive species. Percent cover of native and invasive species, species abundance and reproductive characteristics of the invasive species were monitored during 2-y. Native grasslands coverage was low on all substrate types, demonstrating how slowly calcareous grasslands species establish in such harsh substrate conditions. However, type of substrate did show a significant relationship with plant abundance, with limestone dust being the most beneficial for native species establishment (coverage). Although limestone dust appeared to be the best option for restoring grassland species to limestone quarries (based on its low cost, wide availability, and potential to support native species), it was also likely to support the two invasive species. Functional diversity of the seed mixture had no consistent effect. Our study shows the importance of identifying the most appropriate substrate to both establish calcareous grasslands and resist invasive species. This approach provides insights into developing strategies to conserve biodiversity in industrial and agricultural landscapes with limestone quarries. more...
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- 2019
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17. Mobility of copper and cobalt in metalliferous ecosystems: Results of a lysimeter study in the Lubumbashi Region (Democratic Republic of Congo)
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Grégory Mahy, Amandine Liénard, Donato Kaya Muyumba, Michel Ngongo Luhembwe, Olivier Pourret, Gilles Colinet, and Jessica Bonhoure
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Total organic carbon ,Horizon (geology) ,Dolostone ,Chemistry ,010501 environmental sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Rock fragment ,Geochemistry and Petrology ,Lysimeter ,Environmental chemistry ,Leaching (pedology) ,Siliceous rock ,Soil horizon ,Economic Geology ,0105 earth and related environmental sciences - Abstract
This paper presents the results of a lysimeter experiment in which a forest soil has been artificially spiked with rock fragments from natural copper (Cu) and cobalt (Co)-hills from Tenke-Fungurume (Democratic Republic of Congo). The Cu and Co contents of the percolating water have been analysed at repeated intervals and the impact of rock on the soil properties was evaluated at the end of the experiment. Five rocks were sampled in one copper hill. In natural conditions, these rock fragments located on the top of the hill are mixed to surface soil horizon along the slope through colluvial processes. The Cu and Co contents in rocks range respectively between 470 mg/kg (siliceous rock) and 140,000 mg/kg (shale) and between 450 mg/kg (dolostone) and 5300 mg/kg (shale). Rock fragments were mixed with two horizons (hemi-organic A with 2.7% total organic carbon (TOC), and mineral B with 0.3% TOC) of an acid (pH water The results show great differences between Cu and Co releases in the percolating solutions according to the nature of the rocks. The quantities released were correlated to the concentrations originally present in the unweathered rocks. Differences were also found between the A and B horizons, which indicate that the physicochemical properties of the soil influence reaction with the rocks. The differences between both horizons are mainly organic carbon content, cationic exchange capacity and nutrient content, which were higher in the A horizon. However, the pH of the A horizon was acidic compared with the B horizon. Significant correlations were found between extractable Cu and Co with concentrations of their leaching solution. Because of this, soluble Cu and Co extracted by CaCl2 can be regarded as vertical transfer risk prediction tools of Cu and Co in the soil. more...
- Published
- 2019
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18. Urban alien plants in temperate oceanic regions of Europe originate from warmer native ranges
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Jonathan Lenoir, Jonas J. Lembrechts, Jan Borgelt, Charly Geron, Ivan Nijs, Rafiq Hamdi, Grégory Mahy, Arnaud Monty, Ecologie et Dynamique des Systèmes Anthropisés - UMR CNRS 7058 (EDYSAN), and Centre National de la Recherche Scientifique (CNRS)-Université de Picardie Jules Verne (UPJV) more...
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0106 biological sciences ,[SDV.EE]Life Sciences [q-bio]/Ecology, environment ,Ecology ,Range (biology) ,010604 marine biology & hydrobiology ,[SDE.MCG]Environmental Sciences/Global Changes ,Alien ,[SDV.BID]Life Sciences [q-bio]/Biodiversity ,15. Life on land ,Biology ,010603 evolutionary biology ,01 natural sciences ,Invasive species ,Chemistry ,13. Climate action ,Urbanity ,Plant species ,Temperate climate ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,Alien species ,Ecology, Evolution, Behavior and Systematics - Abstract
International audience; When colonizing new areas, alien plant species success can depend strongly on local environmental conditions. Microclimatic barriers might be the reason why some alien plant species thrive in urban areas, while others prefer rural environments. We tested the hypothesis that the climate in the native range is a good predictor of the urbanity of alien species in the invaded range. The relationship between climate in the native range and the percentage of artificially sealed surfaces (urbanity) at the occurrences of 24 emerging alien plant species, in European areas with a temperate climate (termed oceanic Europe) was evaluated. We found that alien species growing in more urban environments originated from warmer or drier native ranges than found in oceanic Europe. These results have strong conservation implications as climate-warming will likely lift climatic barriers that currently constrain numerous alien plant species to cities, boosting the role of cities as points of entry for invasive plants. more...
- Published
- 2021
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19. A shift from phenol to silica‐based leaf defences during long‐term soil and ecosystem development
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Michel-Pierre Faucon, Jean-Thomas Cornélis, Benjamin L. Turner, Félix de Tombeur, Etienne Laliberté, Graham Zemunik, Hans Lambers, Grégory Mahy, UniLaSalle, Agro-écologie, Hydrogéochimie, Milieux et Ressources (AGHYLE), Université de Liège, Université de Montréal (UdeM), The University of Western Australia (UWA), and Smithsonian Tropical Research Institute more...
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0106 biological sciences ,plant phenols ,phenylalanine ,Chronosequence ,[SDV]Life Sciences [q-bio] ,chemistry.chemical_element ,soil fertility gradient ,Biology ,010603 evolutionary biology ,01 natural sciences ,plant defense strategies ,Soil ,Nutrient ,Phenols ,Species level ,silica-based defense ,resource limitation ,Ecosystem development ,plant-herbivore interactions ,Ecosystem ,Ecology, Evolution, Behavior and Systematics ,ComputingMilieux_MISCELLANEOUS ,2. Zero hunger ,Phenol ,Ecology ,010604 marine biology & hydrobiology ,Phosphorus ,15. Life on land ,[SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics ,Silicon Dioxide ,plant silicon ,Plant Leaves ,Agronomy ,chemistry ,Soil water ,resource availability hypothesis ,Soil fertility ,Bay ,tradeoffs ,[SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis - Abstract
International audience; The resource availability hypothesis predicts that plants adapted to infertile soils have high levels of anti-herbivore leaf defenses. This hypothesis has been mostly explored for secondary metabolites such as phenolics, while it remains underexplored for silica-based defenses. We determined leaf concentrations of total phenols and silicon (Si) in plants growing along the 2million-year Jurien Bay chronosequence, exhibiting an extreme gradient of soil fertility. We found that nitrogen (N) limitation on young soils led to a greater expression of phenol-based defenses, whereas old, phosphorus (P)-impoverished soils favored silica-based defenses. Both defense types were negatively correlated at the community and individual species level. Our results suggest a tradeoff among these two leaf defense strategies based on the strength and type of nutrient limitation, thereby opening up new perspectives for the resource availability hypothesis and plant defense research. This study also highlights the importance of silica-based defenses under low P supply. more...
- Published
- 2021
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20. Long-term silicon dynamics in terrestrial ecosystems: insights from 2-million years soil chronosequences
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Etienne Laliberté, Grégory Mahy, Benjamin L. Turner, Michel-Pierre Faucon, Jean-Thomas Cornélis, Hans Lambers, Graham Zemunik, and Félix de Tombeur
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Silicon ,chemistry ,Earth science ,fungi ,food and beverages ,Environmental science ,chemistry.chemical_element ,Terrestrial ecosystem ,complex mixtures ,Term (time) - Abstract
Silicon (Si) is widely recognized as an important regulator of the global carbon (C) cycle via its effect on diatom productivity in oceans and the weathering of silicate minerals on continents. Si is also a beneficial plant nutrient, improving resistance to herbivory and pathogens and mitigating the negative effects of several abiotic stresses, including nutrient limitation. However, changes in Si sources and cycling during long-term development of terrestrial ecosystems remain poorly understood. We studied Si in soils and plants along two 2-Ma coastal dune chronosequences in southwestern Australia (Jurien Bay and Guilderton). Soil development along these chronosequences includes carbonate leaching in Holocene soils, formation of secondary Si-bearing minerals in Mid-Pleistocene soils, followed by their loss via dissolution, to yield quartz-rich soils of Early-Pleistocene age. The chronosequences also exhibit an extreme gradient of soil fertility in terms of rock-derived nutrients, and shifts from nitrogen (N) to phosphorus (P) limitation of plant productivity as soils age. Along each chronosequence, we quantified the pools of reactive Si-bearing phases and plant-available Si in the soils, and physically extracted soil phytoliths (amorphous silica formed in plant tissues). We also quantified Si, macronutrients and total phenols in the most abundant plants growing along the best-studied of the two chronosequences (Jurien Bay). We found that plant-available Si was lowest in young and carbonate-rich soils, because carbonates weathering reduces the weathering of silicate minerals by consuming protons, and Si is strongly sorbed by secondary minerals in alkaline soils. Plant-available Si increased in intermediate-age soils during the formation of secondary minerals (kaolinite), and finally decreased in old, quartz-rich soils, due to continuous desilication. As pedogenic Si pools became depleted with increasing soil age, Si availability was increasingly determined by soil phytoliths. At Jurien Bay, foliar Si increased continuously as soils aged, in contrast with foliar macronutrients that declined markedly in strongly weathered soils. Finally, foliar phenol concentrations declined with increasing soil age and were negatively correlated with foliar Si at the community and individual species level, suggesting a tradeoff between these two leaf defense strategies. Our results highlight a nonlinear response of plant-available Si to long-term pedogenesis, with an increase during carbonate loss and a decrease in the silicates weathering domain. They also demonstrate that the retention of Si by plants during ecosystem retrogression sustains its terrestrial cycling by leveraging the high reactivity of soil phytoliths compared with soil-derived aluminosilicates. Moreover, the continuous increase of plant Si concentrations as rock-derived nutrients are depleted suggests important plant benefits associated with Si in P-impoverished environments. This is in line with the resource availability hypothesis, which predicts that plants adapted to infertile soils have high levels of anti-herbivore leaf defenses. In particular, old and P-depleted soils increased the relative expression of Si-based defenses, while young soils where plant productivity is limited by N promoted leaf phenol accumulation. Overall, our results demonstrate that long-term ecosystem and soil development strongly influence soil-plant Si dynamics, with cascading effects on plant ecology and global Si and C biogeochemistry. more...
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- 2021
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21. Impact of ecosystem water balance and soil parent material on silicon dynamics: insights from three long-term chronosequences
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Félix de Tombeur, Jean-Thomas Cornélis, Grégory Mahy, Hans Lambers, Benjamin L. Turner, Etienne Laliberté, Michel-Pierre Faucon, UniLaSalle, and Agro-écologie, Hydrogéochimie, Milieux et Ressources (AGHYLE) more...
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010504 meteorology & atmospheric sciences ,Chronosequence ,[SDV]Life Sciences [q-bio] ,Parent material ,Weathering ,complex mixtures ,01 natural sciences ,chemistry.chemical_compound ,Environmental Chemistry ,Ecosystem ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology ,04 agricultural and veterinary sciences ,15. Life on land ,Pedogenesis ,chemistry ,13. Climate action ,Phytolith ,[SDU]Sciences of the Universe [physics] ,Environmental chemistry ,Soil water ,[SDE]Environmental Sciences ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Carbonate ,Environmental science - Abstract
Recent studies demonstrate a strong influence of soil age on long-term silicon (Si) dynamics in terrestrial ecosystems, but how variation in ecosystem water balance and soil parent material impact this trajectory is unknown. We addressed this by studying a 2-million-year dune chronosequence in southwestern Australia characterized by a positive water balance (+ 50 mm year−1) and a lower carbonate concentration in the parent sand (5%) compared with two chronosequences already characterized (− 900 and − 750 mm year−1; 88 and 74%). We sampled soils from the progressive and retrogressive phases of ecosystem development to quantify pedogenic reactive Si (extracted in ammonium oxalate and oxalic acid), phytoliths (biogenic Si), and plant-available Si (extracted in dilute CaCl2). Silicon mobilization was buffered by carbonate in the early stages of the two carbonate-rich drier chronosequences, as previously highlighted, but not in the carbonate-poor wetter chronosequence. Reactive pedogenic Si and plant-available Si did not peak at intermediate stages in the carbonate-poor wetter chronosequence, where almost no clay formation occurred, as it did in the carbonate-rich drier chronosequences during clay formation after carbonate loss. This is probably due to a combination of lower content of weatherable minerals in the soil parent material and higher weathering rates. Phytolith stocks were similar across the three chronosequences, suggesting that a climate-driven increase in biomass and associated phytolith production in wetter sites counterbalance the higher phytolith dissolution rates and physical translocation. Together, these results demonstrate that the initial carbonate concentration in the soil parent material and subsequent mineralogical evolution drive long-term soil Si dynamics, and suggest a significant influence of climate-induced variation in biomass production on the Si biological feedback loop, even in old and highly desilicated environments. more...
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- 2021
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22. Author response for 'A shift from phenol to silica‐based leaf defences during long‐term soil and ecosystem development'
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Graham Zemunik, Félix de Tombeur, Hans Lambers, Benjamin L. Turner, Grégory Mahy, Etienne Laliberté, Jean-Thomas Cornélis, and Michel-Pierre Faucon
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chemistry.chemical_compound ,chemistry ,Environmental protection ,Environmental science ,Phenol ,Ecosystem development ,Term (time) - Published
- 2020
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23. Plants sustain the terrestrial silicon cycle during ecosystem retrogression
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Jean-Thomas Cornélis, Benjamin L. Turner, Michel-Pierre Faucon, Etienne Laliberté, F. de Tombeur, Graham Zemunik, Grégory Mahy, Hans Lambers, UniLaSalle, and Agro-écologie, Hydrogéochimie, Milieux et Ressources (AGHYLE) more...
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inorganic chemicals ,0106 biological sciences ,Biogeochemical cycle ,Silicon ,010504 meteorology & atmospheric sciences ,[SDV]Life Sciences [q-bio] ,Earth science ,chemistry.chemical_element ,complex mixtures ,010603 evolutionary biology ,01 natural sciences ,Carbon cycle ,Soil ,Nutrient ,Ecosystem ,0105 earth and related environmental sciences ,Multidisciplinary ,technology, industry, and agriculture ,Australia ,15. Life on land ,Plants ,equipment and supplies ,Plant Leaves ,stomatognathic diseases ,Pedogenesis ,chemistry ,Environmental science ,Terrestrial ecosystem ,Cycling - Abstract
Terrestrial biogeochemistry of silicon Silicon is an important element in plant tissues and contributes to structural defenses against herbivores and other stresses. However, the terrestrial biogeochemical cycling of silicon is poorly understood, particularly the relative importance of geochemical and biological mechanisms in its regulation. de Tombeur et al. studied this question in 2-million-year chronosequences of soil and vegetation in Western Australia. Sites became progressively more weathered and infertile as they aged, indicating that the silicon cycle shifts from geochemical to biological control as the ecosystem develops (see the Perspective by Carey). They found that foliar silicon concentrations increase continuously during ecosystem development, even though rock-derived silicon is depleted in the older soils. By contrast, other major rock-derived nutrients showed decreasing concentrations in plants. Hence, biological silicon cycling allows plants to maintain concentrations even under conditions of extreme soil infertility. Science , this issue p. 1245 ; see also p. 1161 more...
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- 2020
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24. Topsoil translocation in extensively managed arable field margins promotes plant species richness and threatened arable plant species
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Grégory Mahy, Valentin Gilliaux, E. R. Jasper Wubs, Julien Piqueray, and Terrestrial Ecology (TE)
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Environmental Engineering ,0208 environmental biotechnology ,Biodiversity ,02 engineering and technology ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,Soil ,Topsoil translocation ,Belgium ,Animals ,Waste Management and Disposal ,Ecosystem ,0105 earth and related environmental sciences ,Topsoil ,Endangered Species ,Seed bank ,Arable plant ,Plant community ,General Medicine ,Vegetation ,Plan_S-Compliant_NO ,Plants ,020801 environmental engineering ,Agronomy ,Restoration ,international ,Threatened species ,Seeds ,Environmental science ,Biological dispersal ,Plant cover ,Species richness - Abstract
Since the 1950s, agriculture has intensified drastically, which has led to a significant biodiversity decline on arable lands. This decline was especially dramatic for segetal plant species, the specialist species of cereal fields. Due to the low population density and poor dispersal abilities of many segetal species, the recovery of species-rich fields may fail even though the environmental conditions are suitable. Therefore, conservation efforts including active restoration measures aimed at recovering segetal vegetation are needed. To this purpose, we propose to alleviate dispersal limitation by means of topsoil translocation from a species-rich donor arable field. At two receiver sites, we tested this technique using two topsoil-spreading densities, i.e. 2.5Lsoil/m2 and 5Lsoil/m2 in experimental plots (3 m2). At one receiver site, we tested the impact of topsoil translocation from two different donor sites, while in the other receiver site one donor site was used. We compared plant species diversity and composition of treated plots with control plots as well as with the species composition of the donor sites (field survey) and their seed bank (greenhouse survey). Species richness was increased by topsoil spreading, including richness of threatened species. 33% and 71% of the threatened species were successfully translocated respectively at the two receiver sites. At one site, plant cover was also increased, including threatened species cover. Conversely, topsoil spreading did not promote pernicious species that could affect farmer acceptance negatively. Vegetation of translocated plots was more similar in terms of species composition to donor site seed banks than to donor site field survey. The higher spreading density led to increased species richness when seed bank in topsoil had lower density. Our results show that topsoil translocation can be a highly effective method for restoring threatened segetal plant communities in agricultural landscapes. Even when a full plant community was already present (Receiver 1) topsoil transfer led to a doubling in species richness. The seed bank surveys were a good indicator of plant community composition upon topsoil translocation in the field and are therefore advisable to implement in the project-planning phase to evaluate donor site potential. From our results, we recommend to spread soil at an overall rate of 500 seeds/m2 equivalent. Future studies need to assess the long-term fate of the translocated species as well as the impacts of soil harvests on the donor sites to establish sustainable use levels. more...
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- 2020
25. Resilience and restoration of tropical and subtropical grasslands, savannas, and grassy woodlands
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Gerhard E. Overbeck, William J. Bond, G. Wilson Fernandes, Grégory Mahy, Alessandra Fidelis, Swanni T. Alvarado, Julia-Maria Hermann, Fernando A. O. Silveira, Elise Buisson, Nicholas P. Zaloumis, Soizig Le Stradic, Joseph W. Veldman, and Giselda Durigan more...
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0106 biological sciences ,2. Zero hunger ,0303 health sciences ,geography ,geography.geographical_feature_category ,Agroforestry ,Biodiversity ,Tropical and subtropical grasslands, savannas, and shrublands ,Plant community ,Vegetation ,15. Life on land ,010603 evolutionary biology ,01 natural sciences ,Novel ecosystem ,General Biochemistry, Genetics and Molecular Biology ,Grassland ,03 medical and health sciences ,Disturbance (ecology) ,Ecosystem ,General Agricultural and Biological Sciences ,030304 developmental biology - Abstract
Despite growing recognition of the conservation values of grassy biomes, our understanding of how to maintain and restore biodiverse tropical grasslands (including savannas and open-canopy grassy woodlands) remains limited. To incorporate grasslands into large-scale restoration efforts, we synthesised existing ecological knowledge of tropical grassland resilience and approaches to plant community restoration. Tropical grassland plant communities are resilient to, and often dependent on, the endogenous disturbances with which they evolved - frequent fires and native megafaunal herbivory. In stark contrast, tropical grasslands are extremely vulnerable to human-caused exogenous disturbances, particularly those that alter soils and destroy belowground biomass (e.g. tillage agriculture, surface mining); tropical grassland restoration after severe soil disturbances is expensive and rarely achieves management targets. Where grasslands have been degraded by altered disturbance regimes (e.g. fire exclusion), exotic plant invasions, or afforestation, restoration efforts can recreate vegetation structure (i.e. historical tree density and herbaceous ground cover), but species-diverse plant communities, including endemic species, are slow to recover. Complicating plant-community restoration efforts, many tropical grassland species, particularly those that invest in underground storage organs, are difficult to propagate and re-establish. To guide restoration decisions, we draw on the old-growth grassland concept, the novel ecosystem concept, and theory regarding tree cover along resource gradients in savannas to propose a conceptual framework that classifies tropical grasslands into three broad ecosystem states. These states are: (1) old-growth grasslands (i.e. ancient, biodiverse grassy ecosystems), where management should focus on the maintenance of disturbance regimes; (2) hybrid grasslands, where restoration should emphasise a return towards the old-growth state; and (3) novel ecosystems, where the magnitude of environmental change (i.e. a shift to an alternative ecosystem state) or the socioecological context preclude a return to historical conditions. more...
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- 2018
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26. Using phytostabilisation to conserve threatened endemic species in southeastern Democratic Republic of the Congo
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Olivier Garin, Julien Collignon, Soizig Le Stradic, François Malaisse, Grégory Mahy, Sylvain Boisson, Maxime Seleck, and Mylor Ngoy Shutcha
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0106 biological sciences ,Perennial plant ,Ecology ,media_common.quotation_subject ,Growing season ,Interspecific competition ,Vegetation ,010501 environmental sciences ,Herbaceous plant ,010603 evolutionary biology ,01 natural sciences ,Competition (biology) ,Geography ,Threatened species ,Endemism ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,media_common - Abstract
Outcrops in the southeastern Democratic Republic of the Congo (DRC) are recognized as some of the largest copper–cobalt orebodies in the world. They support a unique vegetation with nearly 600 metallophytes that include rare and endemic species. Mineral exploitation has increased considerably in the region since the 1900s, affecting both environmental and public health. Phytostabilisation of polluted areas represents an opportunity to decrease the bioavailability of heavy metals in the highly polluted soils that result from ore extraction. Such a technique has been successfully implemented near Lubumbashi with the grass Microchloa altera. However, long-term maintenance requires a good understanding of interspecific relationships, such as competition and facilitation. This study tested the establishment success of four herbaceous species from the Katangan Copperbelt by assessing the potential role of Microchloa altera as a nurse species. Two annual and two perennial species were sown in an experiment designed to study the influence of soil amendment and vegetation cover on seedling emergence, growth, and survival. These variables were monitored during the vegetation growing season as well as resprouting success for perennials. Microchloa altera showed a distinct effect on the emergence and survival of annual and perennial species and negatively affected the growth of individuals belonging to both groups of species. more...
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- 2018
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27. Drought stress inducing intraspecific variability in Potentilla tabernaemontani (Rosaceae), a calcareous grassland species
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Grégory Mahy, Arnaud Monty, and Mélanie Harzé
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0106 biological sciences ,Drought stress ,Ecology ,Calcareous grassland ,Rosaceae ,fungi ,food and beverages ,Plant Science ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Intraspecific competition ,Habitat ,Potentilla ,Ecosystem ,Calcareous ,010606 plant biology & botany - Abstract
Background and aims – Calcareous grasslands are among the most species-rich habitats in Western Europe. Populations of plant species characterizing these ecosystems are naturally submitted to high variability in environmental conditions at the very local scale, resulting in pronounced variation in functional traits. Individuals located on xeric parts of calcareous grasslands are characterized by plant traits that potentially ensure more successful performance under stressful conditions. In the context of increased frequency of summer heat waves based on climate change, our aim was to determine a possible intraspecific variability in drought response among individuals of one calcareous grassland plant species.Methods – A greenhouse experiment was set up to follow survival of Potentilla tabernaemontani Asch. individuals according to their habitat of origin (xeric or mesic parts of Belgian calcareous grasslands) and the treatment applied (low or high drought stress).Key results – The results demonstrated that individuals originating from xeric parts survived drought stress better than individuals from mesic parts of calcareous grasslands. Specific leaf area (SLA) of all individuals was very low in the experiment, allowing them to decrease water loss during drought stress. Leaf production was lower for individuals exposed to high drought stress while flower production was higher. That potentially expressed a trade-off between tolerance to water stress, individual growth and reproduction. Conclusions – Local scale environmental heterogeneity deserves to be considered in conservation and restoration plans as it induces intraspecific functional variability between individuals and impacts individuals’ ability to survive drought stress. more...
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- 2018
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28. Towards a population approach for evaluating grassland restoration-a systematic review
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Grégory Mahy, Sylvain Boisson, Arnaud Monty, Carline Pitz, Johannes Kollmann, Mélanie Harzé, and Julia-Maria Hermann
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0106 biological sciences ,geography ,education.field_of_study ,geography.geographical_feature_category ,Ecology ,010604 marine biology & hydrobiology ,Population ,Fragmentation (computing) ,Metapopulation ,010603 evolutionary biology ,01 natural sciences ,Grassland ,education ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Published
- 2018
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29. Increasing plant functional diversity is not the key for supporting pollinators in wildflower strips
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Arnaud Monty, Julien Piqueray, Grégory Mahy, Roel Uyttenbroeck, and Séverin Hatt
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0106 biological sciences ,Ecological niche ,Ecology ,Wildflower ,Pollination ,010604 marine biology & hydrobiology ,fungi ,Niche ,Biodiversity ,food and beverages ,respiratory system ,Biology ,010603 evolutionary biology ,01 natural sciences ,Pollinator ,Species evenness ,Animal Science and Zoology ,Species richness ,human activities ,Agronomy and Crop Science - Abstract
Intensification of agriculture has been one of the major drivers for biodiversity loss in recent decades. Pollinators, which serve an important role in pollinating crops as well as wild plants, have shown a decline in species richness. Flower strips can be used to support pollinators in agro-ecosystems, however the question remains as to how their design can be optimized in order to best benefit pollinators. Increasing plant species diversity has been shown to be beneficial for pollinators, and it is often suggested that functional traits are driving this relationship. Therefore, increasing plant functional diversity could be a tool to support pollinator abundance and diversity. As experimental evidence on this relationship is scarce, we developed a field study with experimental sown flower strips with four functional diversity levels, based on multiple flower traits and with equal plant species richness. We monitored vegetation development, as well as the flower-visiting pollinator community and their interaction networks with flowers. We were able to create a functional diversity gradient while controlling for plant species richness and evenness. However, in contrast to our expectations, pollinator species richness and evenness were not influenced by functional diversity, and increasing functional diversity even resulted in lower flower visitation rates. Network stability metrics showed no effect or negative relationships with functional diversity. We conclude that increasing functional diversity was not the key for supporting pollinators in wildflower strips. Our results also suggest that, for a constant amount of flower resources, increasing plant functional diversity and thus decreasing redundancy of potential pollinator feeding niches, decreases the amount of flower resources present per feeding niche. As pollinator species tended to have less overlap in their feeding niches in flower strips with increased functional diversity, this may lead to a reduction of flower resources available for pollinator species with a more specialized feeding niche. more...
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- 2017
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30. Comment on 'The global tree restoration potential'
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Thomas W. Boutton, Jayashree Ratnam, Forrest Fleischman, Reed F. Noss, Nicola Stevens, Michele de Sá Dechoum, Grégory Mahy, Swanni T. Alvarado, Josep G. Canadell, Christine B. Schmitt, Catherine L. Parr, Juli G. Pausas, A. Carla Staver, Fernando A. O. Silveira, Gerhard E. Overbeck, J. Morgan Varner, Caroline E. R. Lehmann, Alessandra Fidelis, Milton H. Díaz-Toribio, Elise Buisson, Isabel Belloni Schmidt, William J. Bond, Soizig Le Stradic, Nicholas P. Zaloumis, Joseph W. Veldman, John J. Ewel, William A. Hoffmann, Caroline A.E. Strömberg, Ashish N. Nerlekar, Daniel M. Griffith, R. Toby Pennington, Julie C. Aleman, Stephen P. Good, Nina Buchmann, G. Wilson Fernandes, Mahesh Sankaran, Jesse B. Nippert, Colin P. Osborne, Francis E. Putz, Michael P. Perring, T. Michael Anderson, Sally Archibald, Christopher J. Still, Giselda Durigan, Vicky M. Temperton, Julia-Maria Hermann, Texas A&M University [College Station], Université de Montréal (UdeM), Universidade Estadual do Maranhão = State University of Maranhão (UEMA), University of the Witwatersrand [Johannesburg] (WITS), Department of Biological Sciences, University of Cape Town, Cape Town, South Africa, Institute of Agricultural Sciences [Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Oceans and Atmosphere Flagship (CSIRO), CSIRO Oceans and Atmosphere Flagship, Instituto Florestal do Estado de São Paulo, Universidade Federal de Minas Gerais = Federal University of Minas Gerais [Belo Horizonte, Brazil] (UFMG), Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), University of Edinburgh, Gembloux Agro-Bio Tech [Gembloux], Université de Liège, Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), University of Liverpool, Center for Desertification Research (CIDE), Universitat de València (UV), Royal Botanic Garden [Edinburgh], The University of Western Australia (UWA), University of Florida [Gainesville] (UF), Natural Resource Ecology Laboratory [Fort Collins] (NREL), Colorado State University [Fort Collins] (CSU), Universidade de Brasilia [Brasília] (UnB), University of Freiburg [Freiburg], Universität Bonn = University of Bonn, Universidade Federal de Minas Gerais [Belo Horizonte] (UFMG), Yale University [New Haven], Leuphana Universität Lüneburg, Swiss National Science Foundation, Centre National de la Recherche Scientifique (France), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), National Science Foundation (US), Fundação de Amparo à Pesquisa do Estado de São Paulo Minas Gerais, Royal Society (UK), German Research Foundation, Food and Agriculture Organization of the United Nations, Pausas, J. G. [0000-0003-3533-5786], Universidade Estadual de Maranhão, Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), Federal University of Minas Gerais (UFMG), Royal Botanic Garden Edinburgh, University of Bonn, and Pausas, J. G. more...
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0106 biological sciences ,010504 meteorology & atmospheric sciences ,Tree planting ,[SDE.MCG]Environmental Sciences/Global Changes ,Climate change ,010603 evolutionary biology ,01 natural sciences ,Shrubland ,Latitude ,Afforestation ,ComputingMilieux_MISCELLANEOUS ,Organic carbon ,0105 earth and related environmental sciences ,2. Zero hunger ,geography ,Multidisciplinary ,geography.geographical_feature_category ,Forestry ,Soil carbon ,15. Life on land ,[SDE.ES]Environmental Sciences/Environmental and Society ,Tree (data structure) ,Climate change mitigation ,Ecosystems Research ,13. Climate action ,Restoration ,[SDE]Environmental Sciences ,Environmental science ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,grassland - Abstract
Bastin et al.’s estimate (Reports, 5 July 2019, p. 76) that tree planting for climate change mitigation could sequester 205 gigatonnes of carbon is approximately five times too large. Their analysis inflated soil organic carbon gains, failed to safeguard against warming from trees at high latitudes and elevations, and considered afforestation of savannas, grasslands, and shrublands to be restoration., Funding: Supported by the Texas A&M Sid Kyle Global Savanna Research Initiative (T.W.B.); Swiss National Science Foundation (20FI20_173691) (N.B.); Centre National pour la Recherche Scientifique CNRS PICS 2018-2020 (RESIGRASS) (E.B.); CNPq (Brazil, 303179/2016-3) (G.D.); CNPq (Brazil) (G.W.F.); CNPq (Brazil, 303988/2018-5) (A.F.); NASA award NNX17AK14G (F.F.); NSF award 1354943 (W.A.H.); Fundação de Amparo à Pesquisa do Estado de Minas Gerais (Brazil, 2016/13232-5) (S.L.S.); the Office of the Royal Society (IC170015) (C.E.R.L.); CNPq (Brazil, 310345/2018-9) (G.E.O.); the Spanish Government (FIROTIC, PGC2018-096569-B-I00) (J.G.P.); the National Research Foundation (ACCESS, 114695) (N.S.); CNPq (Brazil, 303568/2017-8) (F.A.O.S.); NSF awards 1342703 and 1926431 (C.J.S. and D.M.G.); NSF award EAR-1253713 (C.A.E.S.); Deutsche Forschungsgemeinschaft grant 5579 POEM (V.M.T.); and USDA-NIFA Sustainable Agricultural Systems Grant 12726253 (J.W.V.) more...
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- 2019
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31. A sharp floristic discontinuity revealed by the biogeographic regionalization of African savannas
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Adeline Fayolle, Emily Woollen, Mike D. Swaine, Akomian Fortuné Azihou, Joris P. G. M. Cromsigt, Ben Kirunda, Josiane Seghieri, E. N. Chidumayo, Hélène Dessard, Manfred Finckh, Casey M. Ryan, Aurélie Hick, Paula Nieto-Quintano, Jean-François Gillet, Anthony M. Swemmer, Mariska te Beest, Habte Talila, Ricardo M. Holdo, Rasmus Revermann, Iain McNicol, David Bauman, Julie C. Aleman, Christine B. Schmitt, Grégory Mahy, Anaïs Gorel, Andrew J. Plumptre, Francisco M. P. Gonçalves, Rose Pritchard, Gembloux Agro-Bio Tech [Gembloux], Université de Liège, Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Ecology and Evolutionnary Biology, Yale University [New Haven], Laboratory of Applied Ecology, University of Abomey-Calavi, University of Abomey Calavi (UAC), Université libre de Bruxelles (ULB), Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Forêts et Sociétés (UPR Forêts et Sociétés), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), University of Georgia [USA], Wildlife Conservation Society, Wildlife Conservation Sociecy, School of Geosciences [Edinburgh], University of Edinburgh, Department of Zoology [Cambridge], University of Cambridge [UK] (CAM), Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Kruger National Park, Spatial Ecology and Global Change, and Environmental Sciences more...
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0106 biological sciences ,Woodland ,01 natural sciences ,Floristics ,decay in similarity ,correspondence analysis ,indicator species ,rainfall and altitudetemperature gradients ,biogeographical regions ,Savane ,ComputingMilieux_MISCELLANEOUS ,distance decay in similarity ,0303 health sciences ,Ecology ,Flore ,F70 - Taxonomie végétale et phytogéographie ,Vegetation ,Plante indicatrice ,Geography ,Indicator species ,Ordination ,P01 - Conservation de la nature et ressources foncières ,Biodiversité ,Biologie spatiale ,clustering ,Biologie du sol (relations sol plantes) ,P40 - Météorologie et climatologie ,Biogeography ,Biogéographie ,010603 evolutionary biology ,savannas ,03 medical and health sciences ,floristic clusters ,Ecologie [végétale] ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,distance ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Précipitation ,Ecologie ,Composition botanique ,Species diversity ,rainfall and altitude/temperature gradients ,15. Life on land ,Température ,Species richness - Abstract
Aim: In tropical Africa, savannas cover huge areas, have high plant species richness and are considered as a major natural resource for most countries. There is, however, little information available on their floristics and biogeography at the continental scale, despite the importance of such information for our understanding of the drivers of species diversity at various scales and for effective conservation and management. Here, we collated and analysed floristic data from across the continent in order to propose a biogeographical regionalization for African savannas. Location: We collated floristic information (specifically woody species lists) for 298 samples of savanna vegetation across Africa, extending from 18° N to 33° S and from 17° W to 48° E. Taxa: We focused on native woody species. Methods: We used ordination and clustering to identify the floristic discontinuities and gradual transitions across African savannas. Floristic relationships, specificity and turnover, within and between floristic clusters, were analysed using a (dis-)similarity-based approach. Results: We identified eight floristic clusters across African savannas which in turn were grouped into two larger macro-units. Ordinations at species and genus levels showed a clear differentiation in woody species composition between the North/West macro-unit and the South/East macro-unit. This floristic discontinuity matches to the High (i.e. N&W) and Low (S&E) division of Africa previously proposed by White () and which tracks climatic and topographical variation. In the N&W savannas, the floristic gradient determined by rainfall was partitioned into the Sudanian (drier) and Guinean (wetter) clusters. Within the highly heterogeneous S&E savannas and woodlands, six clusters were identified: Ugandan, Ethiopian, Mozambican, Zambezian, Namibian and South African. Main conclusions: The proposed pan-African classification of savannas and woodlands might assist the development of coordinated management and conservation policies., SCOPUS: ar.j, info:eu-repo/semantics/published more...
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- 2019
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32. Plant community assembly along a natural metal gradient in central Africa: Functional and phylogenetic approach
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Pierre Jacques Meerts, Grégory Mahy, Olivier J. Hardy, Maxime Seleck, Guillaume Delhaye, and Edouard Ilunga wa Ilunga
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environmental filter ,Ecology ,Phylogenetic tree ,metal tolerance ,Central africa ,species turnover ,Plant community ,Plant Science ,Biology ,functional diversity ,trait overdispersion ,Natural (archaeology) ,toxicity gradient ,Phylogenetic diversity ,Functional diversity ,trait clustering ,Evolutionary biology ,copper ,phylogenetic diversity ,Biologie ,Sciences exactes et naturelles - Abstract
Questions: Do functional and phylogenetic diversity vary along a natural metal gradient? Do resources acquisition and metal tolerance-related traits show the same patterns of variation? Is the ability to grow on metal-enriched soil phylogenetically conserved or the result of functional convergence? Location: Fungurume V hill (10°37′03″ S, 26°17′22″ E), Upper Katanga, Democratic Republic of Congo. Methods: In 21 communities along a natural copper gradient, we quantified the variation of species richness and turnover as well as the phylogenetic diversity. We assessed the variation of three univariate functional indices — community-weighted mean, functional richness and functional dispersion — for ten functional traits related to resources acquisition, conservation, dispersal and metal tolerance strategy. Results and Conclusions: Along a gradient of increasing soil Cu concentration, we found a decrease in species number and a strong species turnover. On metal-poor soils, phylogenetic clustering and overdispersion of functional traits indicated selection for certain clades (e.g. Fabaceae) with many different trait combinations suggesting niche partitioning. On metal-enriched soils, contrary to expectations, we found functional convergence towards trait values associated with rapid resource use, lower stature and smaller seeds in several clades. Conversely, metal tolerance strategy showed a clear overdispersion on metal-rich soils reflecting the presence of several strategies to cope with the excess of metal in the soil. This suggests that some extreme toxicity gradients, such as this one, do not always impose strong functional convergence towards a stress tolerance strategy, as is often assumed., SCOPUS: ar.j, info:eu-repo/semantics/published more...
- Published
- 2019
33. Specialized edaphic niches of threatened copper endemic plant species in the D.R. Congo: implications for ex situ conservation
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Olivier Garin, Bastien Lange, Maxime Seleck, Axel Tshomba Wetshy, Grégory Mahy, Mylor Ngoy Shutcha, Nathalie Verbruggen, Wilfried Masengo Kalengo, Sylvain Boisson, Soizig Le Stradic, and Michel-Pierre Faucon more...
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0106 biological sciences ,Ecological niche ,Ecology ,Soil Science ,Edaphic ,Plant Science ,Biology ,010603 evolutionary biology ,01 natural sciences ,Plant ecology ,Habitat ,Soil water ,Ecosystem ,Endemism ,Restoration ecology ,010606 plant biology & botany - Abstract
Copper (Cu) rich soils derived from rocks of the Katangan Copperbelt in the south-eastern Democratic Republic of Congo (DRC) support a rich diversity of metallophytes including 550 heavy metal tolerant; 24 broad Cu soil endemic; and 33 strict Cu soil endemic plant species. The majority of the plant species occur on prominent Cu hills scattered along the copperbelt. Heavy metal mining on the Katangan Copperbelt has resulted in extensive degradation and destruction of the Cu hill ecosystems. As a result, approximately 80 % of the strict Cu endemic plant species are classified as threatened according to IUCN criteria and represent a conservation priority. Little is known about the soil Cu tolerance optimum of the Cu endemic plant species. The purpose of this study was to quantify the soil Cu concentration (Cu edaphic niche) of four Cu endemic plant species to inform soil propagation conditions and microhabitat site selection for planting of the species in Cu hill ecosystem restoration. The soil Cu concentration tolerance of Cu endemic plant species was studied including Crotalaria cobalticola (CRCO); Gladiolus ledoctei (GLLE); Diplolophium marthozianum (DIMA); and Triumfetta welwitschii var. rogersii (TRWE-RO). The in situ natural habitat distributions of the Cu endemic plant species with respect to soil Cu concentration (Cu edaphic niche) was calculated by means of a generalised additive model. Additionally, the seedling emergence and growth of the four Cu endemic plant species in three soil Cu concentrations was tested ex situ and the results were compared to that of the natural habitat soil Cu concentration optimum (Cu edaphic niche). CRCO exhibited greater performance on the highest soil Cu concentration, consistent with its calculated Cu edaphic niche occurring at the highest soil Cu concentrations. In contrast, both DIMA and TRWE-RO exhibited greatest performance at the lowest soil Cu concentration, despite the calculated Cu edaphic niche occurring at moderate soil Cu concentrations. GLLE exhibited equal performances in the entire range of soil Cu concentrations. These results suggest that CRCO evolved via the edaphic specialization model where it is most competitive in Cu hill habitat with the highest soil Cu concentration. In comparison, DIMA and TRWE-RO appear to have evolved via the endemism refuge model, which indicates that the species were excluded into (i.e., took refuge in) the lower plant competition Cu hill habitat due to their inability to effectively compete with higher plant competition on normal soils. The soil Cu edaphic niche determined for the four species will be useful in conservation activities including informing soil propagation conditions and microhabitat site selection for planting of the species in Cu hill ecosystem restoration. more...
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- 2016
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34. Edaphic niches of metallophytes from southeastern Democratic Republic of Congo: Implications for post-mining restoration
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Julie Lebrun, Sylvain Boisson, Maxime Seleck, Grégory Mahy, and Arnaud Monty
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0106 biological sciences ,Ecology ,Soil classification ,Edaphic ,Woodland ,Biology ,010603 evolutionary biology ,01 natural sciences ,Metallophyte ,Soil pH ,Threatened species ,Endemism ,Restoration ecology ,010606 plant biology & botany ,Nature and Landscape Conservation - Abstract
In southeastern D. R. Congo, about 550 metallophytes grow on soils with high copper and cobalt concentrations, 57 of which are endemics to these metalliferous environments. About 70% of those endemics are considered threatened by destruction of habitats through mining activities. To provide guidelines for future restoration programs, the edaphic ecological niches of eight endemic metallophytes (i.e. copper endemics) were studied using a pragmatic sampling method adapted for urgent conservation needs. Niches were modelled using violin plot along Cu, Co and C:N gradients representing the two main independent edaphic gradients among nine edaphic variables (C, N, C:N, K, P, pH, Co, Cu, and Mn). Copper endemics presented distinct edaphic niches along the copper and cobalt gradients, but differentiation was lower along the C:N gradient. In addition, edaphic elements presented covariations among them and metalliferous soils had higher nutrient and element content compared to the non-metalliferous soils of the region dominated by the Miombo woodland. The complexity of the soil composition and the edaphic niches of copper endemics revealed an important challenge in the implementation of the species conservation and the habitat restoration strategies of post-mining sites. more...
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- 2016
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35. Diaspore heteromorphism in the invasive Bromus tectorum L. (Poaceae): Sterile florets increase dispersal propensity and distance
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Arnaud Monty, Cynthia S. Brown, Grégory Mahy, and Laura Maebe
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0106 biological sciences ,Abiotic component ,Diaspore (botany) ,Ecology ,biology ,Seed dispersal ,Plant Science ,Bromus tectorum ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Seed dispersal syndrome ,Inflorescence ,Botany ,Biological dispersal ,Poaceae ,Ecology, Evolution, Behavior and Systematics ,010606 plant biology & botany - Abstract
Within a species, the distance travelled by a particular diaspore depends on its morphology. In Poaceae, the presence of terminal sterile florets can lead to diaspore heteromorphism, which may influence dispersal. We tested the hypothesis that the presence of sterile florets favored dispersal in Bromus tectorum L., an invasive grass in the Western US. We used field and controlled experiments to study the dispersal of caryopses with and without sterile florets attached (respectively complex and simple diaspores), as well as pieces of inflorescence that detached from the mother plants. We considered both primary and secondary dispersal, as well as abiotic and biotic dispersal agents. The distance travelled by the diaspores and their attachment to animal fur were related to the presence and number of sterile florets. Abiotic agents moved diaspores over relatively short distances, both in terms of primary and secondary dispersal. A significant proportion of diaspores attached to fur, suggesting a potential for dispersal over long distances. Complex diaspores were better dispersers than simple ones (and pieces of inflorescence), and this pattern was consistent across the study. However, among complex diaspores, the number of sterile florets had little or no influence. Considering primary and secondary dispersal by abiotic and biotic agents provided a general picture of the dispersal ecology of B. tectorum . For all the dispersal steps and dispersal agents we studied, the presence of sterile florets favored dispersal. These results highlight the functional significance of diaspore heteromorphism induced by floret sterility in the dispersal of Poaceae. more...
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- 2016
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36. Community variation in plant traits along copper and cobalt gradients
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Grégory Mahy, Edouard Ilunga wa Ilunga, Maxime Seleck, Guillaume Delhaye, Pierre Jacques Meerts, Cyrille Violle, and Isaline Daubie
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0106 biological sciences ,Community level ,Ecology ,Specific leaf area ,fungi ,chemistry.chemical_element ,Plant Science ,Biology ,010603 evolutionary biology ,01 natural sciences ,Copper ,Intraspecific competition ,Variation (linguistics) ,chemistry ,Botany ,Plant traits ,Cobalt ,010606 plant biology & botany ,Environmental gradient - Abstract
Questions How do resource acquisition-related traits and stress tolerance-related traits shift along Cu and Co gradients? What are the relative contributions of species turnover and intraspecific variation in driving these shifts? Location Fungurume V hill, Katanga province, Democratic Republic of Congo. Methods We measured five functional traits (vegetative height, leaf area, specific leaf area (SLA) and leaf Cu and leaf Co concentration) related to resource acquisition, competitive ability and metal tolerance strategy for 37 of the most abundant species from 32 plots along natural Cu and Co gradients (from 92 to 6737 mg·kg−1 and 10 to 655 mg·kg−1, respectively). Linear regression was applied to analyse species-level and community-level changes in these traits along the study gradients. Using variance decomposition, we evaluated the relative contribution of intraspecific variation and species turnover to the total community variation along the Cu gradient. Results and Conclusions At the community level, plant height and leaf area decreased while SLA and leaf metal concentrations increased with increasing soil metal concentration. At the species level, patterns were often idiosyncratic and lacked generality. As a result, species turnover was the predominant factor explaining community-level variation along the study gradients, which was particularly clear for variation in leaf Cu concentration. This reflects the constitutive ability of some species to exclude metal, while other species can tolerate high metal concentrations in their leaves. The study emphasizes the importance of evaluating the origin of phenotypic variations observed at the community level. more...
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- 2016
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37. Effects of seed traits variation on seedling performance of the invasive weed, Ambrosia artemisiifolia L
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Arnaud Monty, William Ortmans, and Grégory Mahy
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0106 biological sciences ,education.field_of_study ,Phenotypic plasticity ,biology ,Population ,Maternal effect ,food and beverages ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Invasive species ,Agronomy ,Seedling ,Ruderal species ,education ,Weed ,Ecology, Evolution, Behavior and Systematics ,Ambrosia artemisiifolia ,010606 plant biology & botany ,Nature and Landscape Conservation - Abstract
Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits. However, very few studies have investigated seed traits variations and their consequences on seedling performance. Specifically, the following questions have been addressed by this work: 1) How the seed traits of the invasive Ambrosia artemisiifolia L. vary among mothers and populations, as well as along the latitude; 2) How do seed traits influence seedling performance; 3) Is the influence on seedlings temperature dependent. With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments. During seedling growth, performance-related traits were measured. A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits. more...
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- 2016
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38. Assessment of soil metal distribution and environmental impact of mining in Katanga (Democratic Republic of Congo)
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Gilles Colinet, Olivier Pourret, Bastien Lange, Grégory Mahy, Maxime Seleck, Sophie Decrée, Mylor Ngoy Shutcha, Jessica Bonhoure, Michel-Pierre Faucon, Hydrogeochemistry Interactions Soil Environment unit (HYDRISE), Institut Polytechnique LaSalle Beauvais, UniLaSalle, Laboratoire d'Ecologie végétale et de Biogéochimie, Université libre de Bruxelles (ULB), Department of Biosystem Engineering (BioSE), Gembloux Agro-Bio Tech, Université de Liège, Royal Belgian Institute of Natural Sciences (RBINS), and Université de Lubumbashi more...
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Katanga ,010501 environmental sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Co ,Guide reference ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Geochemistry and Petrology ,Zinc smelting ,Environmental Chemistry ,Organic matter ,Cu ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Chemistry ,Statistics ,Metallurgy ,Lead smelting ,15. Life on land ,Pollution ,Soil contamination ,Phytoremediation ,Metals ,Rhizopshere ,Environmental chemistry ,Soil water ,Soils ,Metalloid ,Environmental impact of mining - Abstract
International audience; Metal and metalloid (As, Cd, Co, Cu, Pb and Zn) distribution in soils from the Katanga Copperbelt (Democratic Republic of Congo) is investigated in order to characterize the environmental impacts of mining and smelting activities in that area. The concentrations of Cu, Co, As, Zn, Pb and Cd in soils from mining sites are higher than in non-metalliferous sites and above permissible metal and metalloid concentrations in soils. Moreover, the fractionation and mobility of Co, and Cu in such environment is assessed using the application of both ammonium acetate-EDTA extraction and speciation modeling (WHAM 6). The resulting data set covers wide range of environmental conditions (pH, trace metals concentration, natural soils and soils affected by mining and ore processing). These extractions show that only a small fraction of Cu and Co is mobile, with variation depending on sites: mobility is higher in soils affected by mining and ore processing. The strong affinity of Mn-oxides for Co may explain lower Co mobility in Mn-rich soils. The high Mn and Fe contents of Cu–Co soils from Katanga may actually exert a protective effect against the toxic effects of Co. Finally, Cu–Co speciation modeling of contaminated sites emphasizes that organic matter strongly sorb Cu whereas Co speciation is mostly by Mn content. This type of study leads to a better understanding of metal fractionation and can guide to define different practices of phytoremediation. more...
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- 2016
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39. Seed desiccation-tolerance is a common feature of threatened taxa in metalliferous tropical grasslands from southeastern DR Congo
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Ann Van de Vyver, Sandrine Godefroid, Grégory Mahy, and Sylvain Boisson
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0106 biological sciences ,Ecology ,010604 marine biology & hydrobiology ,food and beverages ,Tropics ,Tropical and subtropical grasslands, savannas, and shrublands ,Biology ,Ex situ conservation ,010603 evolutionary biology ,01 natural sciences ,Desiccation tolerance ,Taxon ,Agronomy ,Germination ,Threatened species ,Endemism ,Nature and Landscape Conservation - Abstract
In Katanga (southeastern Democratic Republic of Congo), the flora of copper and cobalt deposits is highly threatened by mining. Until mining activity ceases and restoration can take place, seed banking is one of the strategies to be considered for the conservation of these metallophytes of which 32 are strict endemics. In the tropics, however, many species have recalcitrant (desiccation-sensitive) seeds, making them unsuitable for long-term conservation. This study aimed at characterising the seed storage behaviour of 14 taxa of concern from metalliferous tropical grasslands in order to determine their storability in ex situ seed banks. Germination tests of 38 populations from 9 different sites were undertaken on fresh seeds and after 6, 12, 24 and 96 months in dry-cold conditions. The vast majority (93 %) of the sampled species exhibited high seed viability (>75 %). For each taxon studied, there was no significant decline in seed viability during storage. In general, seeds germinated faster after 8 years of storage. This study provides evidence that seed desiccation-tolerance is common among the metallicolous species of Katanga. This highlights their ability to be stored under dry-cold conditions, which opens the way for ex situ conservation programs in seed banks. more...
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- 2020
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40. A framework to identify constraints to post-extinction recovery of plant species—Application to the case of Bromus bromoideus
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Arnaud Monty, Sandrine Godefroid, Julien Piqueray, Louis-Marie Delescaille, and Grégory Mahy
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0106 biological sciences ,Genetic diversity ,Ecology ,Extinct in the wild ,biology ,Agroforestry ,010604 marine biology & hydrobiology ,Endangered species ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Technical feasibility ,Geography ,Biological constraints ,Habitat ,Bromus bromoideus ,Conservation status ,Nature and Landscape Conservation - Abstract
The reintroduction of plant species is a technique increasingly used to restore extirpated populations. Although most often used to improve the conservation status of endangered species, it can also be considered for species extinct in the wild. The process of resurrecting extinct plant species is however still in its infancy, and it entails additional challenges compared to the reintroduction of locally extinct populations. This study proposes a framework to analyse constraints to post-extinction recovery based on the case of Bromus bromoideus, a species endemic to southern Belgium and northern France, extinct in the wild since 1935. The plant still exists in ex situ collections, and seeds stored for decades at 5% moisture content and -20 °C have shown a good viability. We initiated a feasibility study to assess the risks associated to a programme aiming at reviving this long-extinct species. Several constraints were identified. Biological constraints are related to the fuzzy taxonomy of the species, the unknown origin of the seeds and undocumented ex situ cultivation, and the likely low genetic diversity of the material available for reintroduction. Ecological constraints are linked to the habitat of the species. B. bromoideus has no known natural habitat and is only found in cultivated fields, which are by definition highly anthropized unprotected areas. This study shows the importance of undertaking a preliminary study that addresses all aspects of technical feasibility, scientific justification, biological and societal risks. Based on this exercise and inspired by international standards, we developed a decision tool to assist conservationists to resurrect a plant species in the best possible way. more...
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- 2020
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41. The success of rock translocation for populations of the chasmophytic Aeollanthus saxatilis (Lamiaceae)
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Arnaud Monty, Sylvain Boisson, Grégory Mahy, and Audrey Labonté
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0106 biological sciences ,education.field_of_study ,Ecology ,Pollination ,010604 marine biology & hydrobiology ,Population ,food and beverages ,Context (language use) ,Biology ,Generalist and specialist species ,010603 evolutionary biology ,01 natural sciences ,Metallophyte ,Pollinator ,Threatened species ,Guild ,education ,Nature and Landscape Conservation - Abstract
To ensure the rescue, temporary conservation and further restoration of plant populations and communities threatened by exploitation, translocation appears to be an appropriate method in the context of mining. Little is known, however, on its effect on mutualistic interactions, such as pollination, and on the resulting plant population dynamics. Whole-rock translocations were performed as a conservation strategy for the endemic metallophyte flora of Katanga, Democratic Republic of the Congo. The aim of this study was to quantify the flower visitation, sexual reproduction and ramet demographic structure in such a translocated population, and to compare the data with those from natural populations of Aeollanthus saxatilis, one of the threatened species of the chasmophytic community. The study also documented the plant’s flower visitor guild. The ramet density, demographic structure, pollination success and seed abortion rate were assessed in 10 quadrats per population, in the translocated population and in two subsisting natural populations. The flower visitation rate was quantified during three observation periods (20 min each) in six quadrats per population. Small differences were observed in the visitor guild between the translocated and natural populations, but the flower visitation rate was equivalent. No clear difference in the reproductive performance or ramet demographic structure of the populations was found. The flower visitor guild was mainly composed of generalist pollinators, which probably helped in establishing a functional visitor guild at the receptor site. Rock translocation therefore appears to be an encouraging approach, allowing the conservation of functional mutualistic interactions and the maintenance of a population structure comparable to that of natural chasmophytic plant populations. more...
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- 2020
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42. Ecological niche distribution along soil toxicity gradients: Bridging theoretical expectations and metallophyte conservation
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Grégory Mahy, Arnaud Monty, Sylvain Boisson, Michel-Pierre Faucon, Maxime Seleck, Mylor Ngoy Shutcha, Université de Liège - Gembloux, Université de Liège, Department of Biosystem Engineering (BioSE), Gembloux Agro-Bio Tech, Agro-écologie, Hydrogéochimie, Milieux et Ressources (AGHYLE), UniLaSalle, and Gembloux Agro-Bio Tech [Gembloux] more...
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0106 biological sciences ,Research literature ,Ecological niche ,Ecology ,[SDV]Life Sciences [q-bio] ,010604 marine biology & hydrobiology ,Ecological Modeling ,Niche ,15. Life on land ,010603 evolutionary biology ,01 natural sciences ,Metallophyte ,Taxon ,Soil water ,Environmental science ,Concentration gradient - Abstract
International audience; Ecological niche modelling helps us to understand the spatial assembly of species in heterogeneous environments. Three patterns have been widely reported in the research literature regarding the relationship between realised niches and macronutrient concentration gradients: (1) species' optima are unevenly distributed, with a higher frequency in mesic conditions; (2) species' response curves are narrower when optima density is higher; and (3) species with optima at the extremes of the gradients have skewed response curves with a longer tail toward mesic conditions. This study aims to test the existence of these patterns on a vegetation model occurring in metalliferous soils comprising copper and cobalt along a toxicity gradient in southeastern D.R. Congo. Realised niches of 80 taxa were modelled using generalised additive models. The niche optima and the niche widths were determined for each taxon. Results highlighted three groups which differ according to the niche optima location along the soil metal concentration gradients. The patterns found along macronutrient concentration gradients were, to some extent, transposable along micronutrient concentration gradients. Our findings on the diversity and assembly of realised niches has consequences for plant conservation strategies. more...
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- 2020
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43. Management of Grassland-like Wildflower Strips Sown on Nutrient-rich Arable Soils: The Role of Grass Density and Mowing Regime
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Jean-Thomas Cornélis, Julien Piqueray, Virginie Decruyenaere, Valentin Gilliaux, Grégory Mahy, and Roel Uyttenbroeck
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010504 meteorology & atmospheric sciences ,Biodiversity ,010501 environmental sciences ,Biology ,Poaceae ,01 natural sciences ,Grassland ,Soil ,Nutrient ,Animals ,Ecosystem ,0105 earth and related environmental sciences ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,Ecology ,Wildflower ,Noxious weed ,food and beverages ,Nutrients ,Weed control ,Pollution ,Europe ,Agronomy ,Species richness ,Arable land - Abstract
Wildflower strips (WS) are proposed in many European countries as a strategy to enhance biodiversity and ecosystem services in arable fields. To create and maintain WS on nutrient-rich cultivated soils reveals challenging. Flowered species may be outcompeted by grasses due to high phosphorus content in soil. We studied during 5 years seed mixture (grass density in the seed mix) and mowing regime influenced the ability of WS to provide environmental benefits (flower provision for insects and landscape purposes, reduction of soil nutrient load) and respond to farmer concerns (noxious weed promotion, forage production). Lowered grass density increased flower abundance, but not diversity, only in the first 3 years. In the last 2 years mowing effects became determinant. Flower cover and richness were the highest under the twice-a-year mowing regime. This regime also increased forage quantity and quality. Flower colour diversity was conversely the highest where mowing occurred every two years. Potassium in the soil decreased under the twice-a-year mowing regime. Other nutrients were not affected. No management option kept noxious weed to an acceptable level after 5 years. This supports the need to test the efficacy of specific management practices such as selective clipping or spraying. Mowing WS twice a year was retained as the most favourable treatment to maintain species-rich strips with an abundant flower provision. It however implies to mow in late June, i.e. at the peak of insect abundance. It is therefore suggested to keep an unmown refuge zone when applying this management regime. more...
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- 2018
44. Potential of copper-tolerant grasses to implement phytostabilisation strategies on polluted soils in South D. R. Congo
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Grégory Mahy, Michel-Pierre Faucon, Mylor Ngoy Shutcha, François Malaisse, Maxime Seleck, Sylvain Boisson, Soizig Le Stradic, and Julien Collignon
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0106 biological sciences ,Perennial plant ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,Biology ,Poaceae ,Models, Biological ,010603 evolutionary biology ,01 natural sciences ,Species Specificity ,Abundance (ecology) ,Botany ,Soil Pollutants ,Environmental Chemistry ,Environmental Restoration and Remediation ,0105 earth and related environmental sciences ,Phenology ,Andropogon ,Soil classification ,General Medicine ,biology.organism_classification ,Pollution ,Biodegradation, Environmental ,Germination ,Democratic Republic of the Congo ,Quadrat ,Copper - Abstract
Phytostabilisation (i.e. using plants to immobilise contaminants) represents a well-known technology to hamper heavy metal spread across landscapes. Southeastern D.R. Congo, Microchloa altera, a tolerant grass from the copper hills, was recently identified as a candidate species to stabilise copper in the soil. More than 50 grasses compose this flora, which may be studied to implement phytostabilisation strategies. However, little is known about their phenology, tolerance, reproductive strategy or demography. The present study aims to characterize the Poaceae that may be used in phytostabilisation purposes based on the following criteria: their ecological distribution, seed production at two times, abundance, soil coverage and the germination percentage of their seeds. We selected seven perennial Poaceae that occur on the copper hills. Their ecological distributions (i.e. species response curves) have been modelled along copper or cobalt gradients with generalised additive models using logic link based on 172 presence-absence samples on three sites. For other variables, a total of 69 quadrats (1 m(2)) were randomly placed across three sites and habitats. For each species, we compared the number of inflorescence-bearing stems (IBS) by plot, the percentage of cover, the number of seeds by IBS and the estimated number of seeds by plot between sites and habitat. Three species (Andropogon schirensis, Eragrostis racemosa and Loudetia simplex) were very interesting for phytostabilisation programs. They produced a large quantity of seeds and had the highest percentage of cover. However, A. schirensis and L. simplex presented significant variations in the number of seeds and the percentage of cover according to site. more...
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- 2015
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45. Specialist plant species harbour higher reproductive performances in recently restored calcareous grasslands than in reference habitats
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Jean-Philippe Bizoux, Grégory Mahy, Mélanie Harzé, Arnaud Monty, and Julien Piqueray
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Fragmentation (reproduction) ,FITNESS ,Ecology ,CALCAREOUS GRASSLAND ,Calcareous grassland ,ECOLOGICAL RESTORATION ,Plant Science ,Biology ,Biodiversity hotspot ,Ecological resilience ,PLANT POPULATION ,SPECIALIST ,Habitat ,REPRODUCTIVE SUCCESS ,Temperate climate ,ECOLOGICAL RESILIENCE ,Calcareous ,Restoration ecology - Abstract
Background and aims – Calcareous grasslands are local biodiversity hotspots in temperate regions that suffered intensive fragmentation. Ecological restoration projects took place all over Europe. Their success has traditionally been assessed using a plant community approach. However, population ecology can also be useful to assess restoration success and to understand underlying mechanisms. Methods – We took advantage of three calcareous grassland sites in Southern Belgium, where reference parcels coexist with parcels restored in the late twentieth century and with more recently restored parcels. We evaluated the colonization stage of three specialist species ( Sanguisorba minor, Potentilla neumanniana and Hippocrepis comosa ) using occurrence data. We also measured the reproductive traits of 120 individuals per species and compared components of fitness between recent restorations, old restorations and reference habitats. Key results – We found that the occurrence of H. comosa was similar in the different restoration classes, whereas both P. neumanniana and S. minor occurrences decreased from reference grasslands to recent restorations. In contrast, these two latter species exhibited a much higher reproductive output in recent restorations, thanks to an increased production of flowers and seeds. Conclusions – Our results suggest that, during colonization of recently restored calcareous grasslands, favourable environmental conditions, low competition and sufficient genetic mixing may lead to an increased fitness of individuals and a faster population growth than in the reference habitat. These results demonstrate how population processes can increase ecological resilience and highlight the interest of a population-based approach to assess the success of ecological restoration. more...
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- 2015
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46. Copper and cobalt accumulation in plants: a critical assessment of the current status of knowledge
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Alan J. M. Baker, Michel-Pierre Faucon, Olivier Pourret, Guillaume Echevarria, Antony van der Ent, Pierre Jacques Meerts, Bastien Lange, François Malaisse, Nathalie Verbruggen, Grégory Mahy, UniLaSalle, Laboratoire Sols et Environnement (LSE), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Gembloux Agro-Bio Tech [Gembloux], Université de Liège, Dept Forest Nat & Landscape, Biodivers & Landscape Unit, Lab Plant Ecol & Biogeochem, Université Libre de Bruxelles [Bruxelles] (ULB), Laboratoire de Physiologie et de Génétique Moléculaire des Plantes, Belgian Fund for Scientific Research (FRS-FNRS, Belgium), Australian Research Council Discovery Early Career Researcher Award DE160100429, ANR-10-LABX-0021/10-LABX-0021,RESSOURCES21,Strategic metal resources of the 21st century(2010), and ANR-14-CE04-0005,AGROMINE,Agromine des métaux stratégiques issus de matrices contaminées(2014) more...
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0106 biological sciences ,metal tolerance ,Physiology ,Metallophyte ,chemistry.chemical_element ,Plant Science ,copper (Cu) ,010501 environmental sciences ,Biology ,01 natural sciences ,Metal- tolerance ,Species Specificity ,hyperaccumulation ,Accumulation ,Ultramafic rock ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Botany ,Hyperaccumulator ,0105 earth and related environmental sciences ,fungi ,toxicity ,food and beverages ,phytomining ,Toxicity ,Cobalt ,Plants ,Copper ,Biological Evolution ,Phytoremediation ,chemistry ,cobalt (Co) ,Soil water ,Shoot ,Phytomining ,Hyperaccumulation ,metallophyte ,accumulation ,Plant Shoots ,010606 plant biology & botany - Abstract
This review synthesizes contemporary understanding of copper–cobalt (Cu–Co) tolerance and accumulation in plants. Accumulation of foliar Cu and Co to > 300 μg g−1 is exceptionally rare globally, and known principally from the Copperbelt of Central Africa. Cobalt accumulation is also observed in a limited number of nickel (Ni) hyperaccumulator plants occurring on ultramafic soils around the world. None of the putative Cu or Co hyperaccumulator plants appears to comply with the fundamental principle of hyperaccumulation, as foliar Cu–Co accumulation is strongly dose-dependent. Abnormally high plant tissue Cu concentrations occur only when plants are exposed to high soil Cu with a low root to shoot translocation factor. Most Cu-tolerant plants are Excluders sensu Baker and therefore setting nominal threshold values for Cu hyperaccumulation is not informative. Abnormal accumulation of Co occurs under similar circumstances in the Copperbelt of Central Africa as well as sporadically in Ni hyperaccumulator plants on ultramafic soils; however, Co-tolerant plants behave physiologically as Indicators sensu Baker. Practical application of Cu–Co accumulator plants in phytomining is limited due to their dose-dependent accumulation characteristics, although for Co field trials may be warranted on highly Co-contaminated mineral wastes because of its relatively high metal value. more...
- Published
- 2017
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47. The voluntary Code of conduct on invasive alien plants in Belgium: results and lessons learned from the AlterIAS LIFE+ project
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Sabine Wallens, Leen Heemers, Grégory Mahy, Etienne Branquart, Catherine Mathys, Arnaud Monty, Sonia Vanderhoeven, D. van Wesemael, and Mathieu Halford
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Code of conduct ,Political science ,Plant Science ,Alien ,Horticulture ,Agronomy and Crop Science ,Humanities - Abstract
Voluntary approaches have been recently used in the horticultural sector to deal with the introduction and spread of invasive alien plants. In Belgium, the first Code of conduct has been developed within the frame of the AlterIAS project, a LIFE+ “Information & Communication” project aiming at raising the awareness of horticulture professionals and gardeners on the invasive plants issue. The Belgian Code was prepared in consultation with representatives from the ornamental sector, public authorities and the scientific community. The Code was promoted throughout the country with a specific communication campaign entitled “Plant different”. Thanks to communication efforts, a positive dynamic of involvement was observed over time. Surveys were performed to assess the changes of attitudes and the perception of the Code by the target audience of the project. Positive results were achieved for horticulture professionals. However, the Code will require more time to be widely adopted by the ornamental sector in Belgium. Code de conduite volontaire sur les plantes envahissantes en Belgique: resultats et retour d'experience du projet AlterIAS LIFE+ Les approches volontaires ont ete recemment utilisees dans le secteur horticole pour limiter l'introduction et la dissemination des plantes exotiques envahissantes. En Belgique, le premier Code de conduite a ete mis au point dans le cadre du projet AlterIAS, un projet LIFE+ « Information & Communication » visant a favoriser la prise de conscience des questions liees aux plantes envahissantes chez les professionnels de l'horticulture et chez les jardiniers. Le Code belge a ete prepare en concertation avec des representants du secteur des plantes ornementales, des autorites publiques, ainsi que de la communaute scientifique. Ce Code a ete mis en avant dans l'ensemble du pays avec une campagne de communication specifique « Plantons autrement ». Grâce aux efforts de communication, une dynamique d'implication positive a ete observee au cours du temps. Des etudes ont ete menees pour evaluer les changements d'attitudes et la perception du Code par son public cible. Des resultats positifs ont ete obtenus aupres des professionnels de l'horticulture. Le Code demandera cependant plus de temps pour etre adopte de maniere plus large par le secteur ornemental en Belgique. Дoбpoвoльный Кoдeкc пoвeдeния в oтнoшeнии инвaзивныx чyжepoдныx pacтeний в Бeльгии: peзyльтaты и ypoки, извлeчeнныe из пpoeктa AlterIAS LIFE+ Дoбpoвoльныe пoдxoды нeдaвнo иcпoльзoвaлиcь в ceктope caдoвoдcтвa для paбoты c интpoдyкциeй и pacпpocтpaнeниeм чyжepoдныx инвaзивныx pacтeний. B Бeльгии пepвыe кoдeкcы пoвeдeния были paзpaбoтaны в paмкax пpoeктa AlterIAS LIFE+ «Инфopмaция и Кoммyникaция», нaцeлeннoгo нa пoвышeниe ocвeдoмлeннocти пpoфeccиoнaлoв плoдoвoдcтвa и caдoвoдoв в oтнoшeнии пpoблeмы инвaзивныx pacтeний. Бeльгийcкий Кoдeкc был пoдгoтoвлeн в xoдe кoнcyльтaций c пpeдcтaвитeлями ceктopa дeкopaтивныx pacтeний, opгaнoв гocyдapcтвeннoй влacти и нayчнoгo cooбщecтвa. Блaгoдapя нayчнo-пpocвeтитeльcкoй кaмпaнии пoд нaзвaниeм «Caжaй c oглядкoй», кoдeкc pacпpocтpaнялcя пo вceй cтpaнe, и в тeчeниe дoлгoгo вpeмeни oтмeчaлacь пoлoжитeльнaя динaмикa вoвлeчeннocти. Были пpoвeдeны oпpocы, пoзвoляющиe oцeнить измeнeния пcиxoлoгичecкиx ycтaнoвoк и вocпpиятия Кoдeкca цeлeвoй ayдитopиeй пpoeктa. B oтнoшeнии пpoфeccиoнaлoв плoдoвoдcтвa были дocтигнyты пoлoжитeльныe peзyльтaты. Oднaкo пoтpeбyeтcя бoльшe вpeмeни для шиpoкoгo пpинятия Кoдeкca ceктopoм дeкopaтивныx pacтeний в Бeльгии. more...
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- 2014
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48. Speciation slowing down in widespread and long-living tree taxa: insights from the tropical timber tree genus Milicia (Moraceae)
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Christopher W. Dick, Grégory Mahy, Brice Sinsin, Jean-Louis Doucet, Kasso Daïnou, Olivier J. Hardy, M. Pluijgers, Philippe Lejeune, Jérôme Duminil, and Armel S L Donkpegan
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Systematics ,Paraphyly ,Genetic Speciation ,Molecular Sequence Data ,Biology ,Moraceae ,Coalescent theory ,Evolution, Molecular ,Monophyly ,Phylogenetics ,Genetics ,Clade ,Phylogeny ,Genetics (clinical) ,DNA Primers ,Base Sequence ,Models, Genetic ,Ecology ,Bayes Theorem ,Sequence Analysis, DNA ,Reproductive isolation ,Biological Evolution ,Phylogeography ,Haplotypes ,Evolutionary biology ,Multigene Family ,Africa ,Original Article ,Microsatellite Repeats - Abstract
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 that 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 nonadmixed 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. more...
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- 2014
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49. Why some species cannot colonise restored habitats? The effects of seed and microsite availability
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Grégory Mahy, Julien Piqueray, Layla Saad, and Jean-Philippe Bizoux
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Ecology ,biology ,food and beverages ,Veronica prostrata ,Trifolium montanum ,Microsite ,biology.organism_classification ,Generalist and specialist species ,Colonisation ,Agronomy ,Germination ,Seedling ,Botany ,Litter ,Nature and Landscape Conservation - Abstract
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 colonising restored habitats. We aimed at explaining this lack of colonisation 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 colonisation, 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. more...
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- 2013
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50. Implication of plant-soil relationships for conservation and restoration of copper-cobalt ecosystems
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Mylor Ngoy Shutcha, Edouard Ilunga wa Ilunga, Michel-Pierre Faucon, Pierre Jacques Meerts, Olivier Pourret, Grégory Mahy, Soizig Le Stradic, Delhaye Guillaume, Sylvain Boisson, Bastien Lange, Maxime Seleck, UniLaSalle, Hydrogeochemistry Interactions Soil Environment unit (HYDRISE), Institut Polytechnique LaSalle Beauvais, Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Université de Lubumbashi, Gembloux Agro-Bio Tech [Gembloux], Université de Liège, and Université de Lubumbashi (UNILU) more...
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0106 biological sciences ,Restoration ecology ,Biologie du sol (relations sol plantes) ,Metallophyte ,Soil Science ,Plant Science ,010501 environmental sciences ,Biology ,Biodiversity conservation ,01 natural sciences ,Critically endangered ,Pollution du sol ,Relation sols-plantes ,Pédologie ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Ecosystem ,chemical soil factors ,Chemical soil factors ,Endemism ,heavy metals ,restoration ecology ,0105 earth and related environmental sciences ,Ecologie ,Ecology ,Plant community ,15. Life on land ,soil-plant interactions ,Phytoremediation ,Habitat ,Heavy metals ,13. Climate action ,Bioremédiation du sol ,endemism ,metallophyte ,biodiversity conservation ,010606 plant biology & botany ,Soil-plant interactions - Abstract
Background: Chemical soil factors play an important role in generating and maintaining plant diversity. Naturally metal-enriched habitats support highly distinctive plant communities consisting of many rare and endemic species. Species of these plant communities possess remarkable physiological adaptations and are now being considered key elements in the implementation of green technologies aimed at phytoremediation of contaminated soils and post-mined soils. Several studies have emphasised that industrial mineral extraction results in serious damage to ecosystems and serious threats to human health and leads to the extinction of metallophyte species. In the southeastern Democratic Republic of the Congo (DRC), mining activities represent a threat to the long-term persistence of communities located on metalliferous copper and cobalt outcrops and their associated endemic metallophytes, which are currently considered some of the most critically endangered plants in the world. Scope: Plant diversity conservation of metal-rich soils must assess soil-plant relationships at different scales (ecosystems, communities, and populations) to define in-situ and ex-situ conservation and restoration projects. This paper proposes a review of soil-plant relationships involved in plant diversity and endemism and their implications for biodiversity conservation and restoration., SCOPUS: ar.j, info:eu-repo/semantics/published more...
- Published
- 2016
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