References of "Delhaye, Guillaume"
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See detailInterspecific trait integration increases with environmental harshness: a case study along a metal toxicity gradient
Delhaye, Guillaume; Bauman, David; Seleck, Maxime ULiege et al

in Functional Ecology (2020)

1. Functional traits are commonly used to calculate a wide array of functional diversity indices to infer different mechanisms of community assembly and spe-cies coexistence. Recently, the degree of ... [more ▼]

1. Functional traits are commonly used to calculate a wide array of functional diversity indices to infer different mechanisms of community assembly and spe-cies coexistence. Recently, the degree of interspecific covariation between multi-ple 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.2. 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 princi-pal component analysis on the traits of the species in a local community (multivari-ate ITI index) and the correlations between traits in local communities (bivariate ITI index).3. We show that the plant metal tolerance strategy (i.e. leaf metal content) is rela-tively 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 in-tegration 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.4. 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 en-vironments select increasingly coordinated sets of functional traits, in turn pos-sibly driving the decrease in species richness. Further studies should assess the generality and underlying physiological mechanisms of such ecological patterns. [less ▲]

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See detailPlant community assembly along a natural metal gradient in central Africa: Functional and phylogenetic approach
Delhaye, Guillaume; Hardy, Olivier J.; Seleck, Maxime ULiege et al

in Journal of Vegetation Science (2019)

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 ... [more ▼]

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. [less ▲]

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See detailVariation in copper and cobalt tolerance and accumulation among six populations of the facultative metallophyte Anisopappus chinensis (Asteraceae)
Lange, Bastien; Delhaye, Guillaume; Boisson, Sylvain ULiege et al

in Environmental and Experimental Botany (2018), 153

Advances on the ecology and evolution of adaptation to metal toxicity are based on studying metallophytes that are not restricted to soils strongly enriched in trace elements. The evolution of Cu and Co ... [more ▼]

Advances on the ecology and evolution of adaptation to metal toxicity are based on studying metallophytes that are not restricted to soils strongly enriched in trace elements. The evolution of Cu and Co tolerance and accumulation, which principally occurs among the Copperbelt of Central Africa, is poorly known. In this paper, we studied Cu and Co tolerance and accumulation in a facultative metallophyte occupying a very broad ecological niche in southeastern Democratic Republic of Congo: Anisopappus chinensis (Asteraceae). The population variation in Cu and Co tolerance and accumulation was experimentally investigated using four metallicolous and two non-metallicolous populations from contrasted habitats. Surprisingly, Cu tolerance was poorly expressed in metallicolous populations grown in hydroponics, suggesting that specific rhizosphere processes may account for the ability to grow without toxicity symptoms under high Cu concentration on metalliferous soils. Population variation in Co tolerance and accumulation was demonstrated, which positively correlated to the concentration of Co in the native soil. Increased tolerance seems to have evolved in populations originating from Co-enriched soils. Foliar Co accumulation above 300 mg kg⁻¹ dry weight with increased translocation was observed in the most tolerant populations, possibly making such populations promising materials to test for Co-phytomining applications. [less ▲]

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See detailPlant and fish production performance, nutrient mass balances, energy and water use of the PAFF Box, a small-scale aquaponic system
Delaide, Boris ULiege; Delhaye, Guillaume; Dermience, Michael et al

in Aquacultural Engineering (2017), 78

Aquaponics is an integrated farming concept that combines fish and hydroponic plant production in a recirculating water system. This food production system promises a reduced environmental footprint when ... [more ▼]

Aquaponics is an integrated farming concept that combines fish and hydroponic plant production in a recirculating water system. This food production system promises a reduced environmental footprint when compared to conventional farming systems. However, questions regarding its sustainability remain and there is a lack of data on its performance. A small-scale aquaponic system named PAFF Box (Plant And Fish Farming Box) consisting of a ship container topped by a greenhouse was studied. Plant yield in ebb-and-flow and deep water culture (DWC) hydroponic beds, lettuce, basil and tilapia production capacity and water and energy consumption were investigated. Additionally, all macro- and micronutrient mass balances were analyzed in order to give a better picture of their dynamics and recycling ability. Thanks to the daily inputs of tap water, and 42g of feed per m2 of plant beds, DWC beds showed 3 to 10 fold higher plant yields than ebb and flow. The production of 1kg of vegetable in DWC consumed 244L of water and 84.5kWh of electricity and 1kg increase of tilapia consumed 278L and 96.2kWh. The system was very efficient in water use for fish production but alternative solutions for warming the water and fine-tuned pumping setup are required to decrease energy needs. Key nutrients such as potassium, phosphorus, iron, copper, zinc, manganese and molybdenum, remained low in solution. Nitrate, calcium, boron and sodium concentrations increased quickly and only water exchange could control their accumulation meanwhile a low daily water exchange rate of 3.6\% implicated a high nutrient loss in the environment. In the willingness to decrease aquaponics environmental footprint, this study indicates that improved designs could be explored such as decoupled aquaponic systems. [less ▲]

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See detailCommunity variation in plant traits along copper and cobalt gradients
Delhaye, Guillaume; Violle, Cyrille; Seleck, Maxime ULiege et al

in Journal of Vegetation Science (2016), 27(4), 854-864

Questions: How do resource acquisition-related traits and stress tolerancerelated traits shift along Cu and Co gradients? What are the relative contributions of species turnover and intraspecific ... [more ▼]

Questions: How do resource acquisition-related traits and stress tolerancerelated 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. [less ▲]

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See detailVariation des traits fonctionnels le long d’un gradient de cuivre et cobalt : contribution du remplacement d’espèces et de la variabilité intraspécifique
Delhaye, Guillaume; Violle, Cyril; Seleck, Maxime ULiege et al

Conference (2014, April)

Les collines cuprocobaltifères du Katanga sont des lieux privilégiés pour étudier la variation des traits fonctionnels le long de gradients de stress métallique. Nous avons étudié la variation de six ... [more ▼]

Les collines cuprocobaltifères du Katanga sont des lieux privilégiés pour étudier la variation des traits fonctionnels le long de gradients de stress métallique. Nous avons étudié la variation de six traits à l’échelle des espèces et de la communauté le long d’un gradient de cuivre et cobalt. D’autres paramètres tels que la concentration en phosphore et l’humidité du sol covarient positivement avec la teneur en métal du sol. Les contributions relatives du remplacement d’espèces et de la variabilité intraspécifique à la variabilité totale des traits dans les communautés ont été déterminées. A l’échelle de la communauté, la hauteur et la surface foliaire diminuent alors que les valeurs des quatre autres traits augmentent le long du gradient. Les espèces montrent des réponses variées, généralement non significatives. Pour tous les traits, le remplacement d’espèce est le moteur principal de la variation au sein des communautés. La concentration en métal du sol implique des réponses variées sur les différents traits et les différentes espèces. Nous montrons que la concentration croissante en métal privilégie le remplacement d’espèce par rapport à la variation intraspécifique et que les espèces répondent par différentes stratégies de tolérance à la concentration en métal du le sol. La variation des traits à l’échelle des communautés est essentiellement le reflet d’un changement dans les abondances des différentes formes de vie. Les espèces à xylopodes sont dominantes sur sol pauvre en métal alors que les annuelles sont dominantes sur sol très enrichi. [less ▲]

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