References of "Carnol, Monique"
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See detailBelowground biodiversity relates positively to ecosystem services of European forests
Bakker, Mark R.; Brunner, Ivano; Ashwood, Francis et al

in Frontiers in Forests and Global Change (2019), 2

Biodiversity of ecosystems is an important driver for the supply of ecosystem services to people. Soils often have a larger biodiversity per unit surface area than what can be observed aboveground. Here ... [more ▼]

Biodiversity of ecosystems is an important driver for the supply of ecosystem services to people. Soils often have a larger biodiversity per unit surface area than what can be observed aboveground. Here, we present what is to our knowledge, the most extensive literature-based key-word assessment of the existing information about the relationships between belowground biodiversity and ecosystem services in European forests. The belowground diversity of plant roots, fungi, prokaryota, soil fauna and protists was evaluated in relation to the supply of Provisioning, Regulating, Cultural and upporting Services. The soil biota were divided into 14 subgroups and the ecosystem services into 37 separate services. Out of the 518 possible combinations of biotic groups and ecosystem services, no published study was found for 374 combinations (72%). Of the remaining 144 combinations (28%) where relationships were found, the large majority (87%) showed a positive relationship between biodiversity of a belowground biotic group and an associated ecosystem service. However, for the majority of the combinations (102) there were only three or fewer studies. The percentage of cases for which a relationship was detected varied strongly between ecosystem service categories with 23% for Provisioning, 8% for Regulating, 40% for Cultural and 48% for Supporting Services. We conclude that (1) soil biodiversity is generally positively related to ecosystem services in European forests; (2) the links between soil biodiversity and Cultural or Supporting services are better documented than those relating to Provisioning and Regulating services; (3) there is a huge knowledge gap for most possible combinations of soil biota and ecosystem services regarding how a more biodiverse soil biota is associated with a given ecosystem service.Given the drastically increasing societal demand for knowledge of the role of biodiversity in the functioning of ecosystems and the supply of ecosystem services, we strongly encourage the scientific community to conductwell-designed studies incorporating the belowground diversity and the functions and services associated with this diversity. [less ▲]

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See detailIdentifying the tree species compositions that maximize ecosystem functioning in European forests
Baeten, Lander; Bruelheide; van der Plas, Fons et al

in Journal of Applied Ecology (2019), 56

1. Forest ecosystem functioning generally benefits from higher tree species richness, but within richness levels variation is typically large, mostly due to the contrasting performances of communities ... [more ▼]

1. Forest ecosystem functioning generally benefits from higher tree species richness, but within richness levels variation is typically large, mostly due to the contrasting performances of communities with different compositions. Evidence-based understanding of composition effects on forest productivity as well as on multiple other functions has large practical relevance, because forest managers are more likely to be concerned with the selection of species that maximize functioning rather than with diversity per se. 2. Here we used a dataset of thirty ecosystem functions measured in stands with different species richness and composition in six European forest types. First, we quantified whether the compositions that maximize annual aboveground wood production (productivity) generally also fulfill the multiple other ecosystem functions (multifunctionality). Then, we quantified the species identify effects and strength of interspecific interactions, to identify the “best” and “worst” species composition for multifunctionality. Finally, we evaluated the real-world frequency of occurrence of best and worst mixtures, using harmonized data from multiple national forest inventories. 3. The most productive tree species combinations also tended to express relatively high multifunctionality, although we found a relatively wide range of compositions with high or low average multifunctionality for the same level of productivity. Monocultures were distributed among the highest as well as the lowest performing compositions. The variation in functioning between compositions was generally driven by differences in the performance of the component species and, to a lesser extent, by particular interspecific interactions. Finally, we found that the most frequent species compositions in inventory data were monospecific stands and that the most common compositions showed below-average multifunctionality and productivity. 4. Synthesis and applications. While a management focus on productivity does not necessarily trade-off against other ecosystem functions, it matters considerably which particular tree species and combinations are promoted. These identity and composition effects are essential in thecontext of developing high-performing production systems, for instance in forestry and agriculture, and deserve much more attention in the analysis and design of functional biodiversity studies if the aim is to inform ecosystem management. [less ▲]

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See detailHomology modeling and in vivo functional characterization of the zinc permeation pathway in a heavy metal P-type ATPase
Lekeux, Gilles ULiege; Crowet, Jean-Marc; Nouet, Cécile ULiege et al

in Journal of Experimental Botany (2019), 70

The P1B ATPase Heavy Metal ATPase 4 (HMA4) is responsible for zinc and cadmium translocation from roots to shoots in the plant Arabidopsis thaliana. It couples ATP hydrolysis to cytosolic domain movements ... [more ▼]

The P1B ATPase Heavy Metal ATPase 4 (HMA4) is responsible for zinc and cadmium translocation from roots to shoots in the plant Arabidopsis thaliana. It couples ATP hydrolysis to cytosolic domain movements enabling metal transport across the membrane. Thanks to high conservation level within the P-type ATPase family, the role of the HMA4 cytoplasmic catalytic domains can be inferred from well characterized pumps. In contrast, the function of its terminal cytosolic extensions as well as the metal permeation mechanism through the membrane remains elusive. Here, homology modeling of the HMA4 transmembrane region was conducted based on the crystal structure of a ZntA bacterial homolog. The analysis highlighted amino acids forming a metal permeation pathway, whose importance was subsequently investigated functionally through mutagenesis and complementation experiments in plants. Although the zinc pathway displayed overall conservation among the two proteins, significant differences were observed, especially in the entrance area with altered electronegativity and the presence of a salt bridge/H-bond network. The analysis also newly identified amino acids whose mutation results in total or partial loss of the protein function. In addition, comparison of zinc and cadmium accumulation in shoots of A. thaliana complemented lines revealed a number of HMA4 mutants exhibiting different abilities in zinc and cadmium translocation. These observations could be instrumental to design low cadmium accumulating crops, hence decreasing human cadmium exposure . [less ▲]

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See detailAn indicator for organic matter dynamics in temperate agricultural soils
Wesemael, Bas Van; Chartin, Caroline; Wiesmeier, Martin et al

in Agriculture, Ecosystems and Environment (2019), 274

The heterogeneity of soil organic matter (SOM) and the small changes in soil organic carbon (SOC) compared to large total SOC stocks hinder a robust estimation of SOC turnover, in particular for more ... [more ▼]

The heterogeneity of soil organic matter (SOM) and the small changes in soil organic carbon (SOC) compared to large total SOC stocks hinder a robust estimation of SOC turnover, in particular for more stable SOC. We developed a simple fractionation protocol for agricultural topsoils and tested it extensively on a range of soils in southern Belgium, including farmed soils, soils from long-term field trials, and paired sites after recent conversion to conservation farming. Our simple fractionation involves shaking the soil, wet sieving over 20 μm and analysing the SOC concentration in the soil as well as in the fine fraction (<20 μm). Eight biological indicators measured in an earlier study across the same monitoring network for the 0–10 cm topsoil were analysed in a conditional inference forest model in order to investigate the factors influencing the SOC fractions. Soil microbial biomass N explained the largest proportion of variation in both fractions. The fine fraction was also associated with factors explaining the regional trend in SOC distribution such as farmyard manure input, precipitation, land use and flow length. The variation in SOC content between treatments both in long-term trials and in farmers’ fields converted to conservation management was mainly attributed to changes within the coarse fraction. Thus, this fraction proves to be sensitive to management changes, although care should be taken to sample deep enough to represent the former plough layer inherited from the conventional tillage practice. Furthermore, the ratio between the coarse and the fine fraction showed a linear relationship (r² = 0.66) with the relative changes in SOC concentration over the last ten years. These fractions derived from a simple analytical approach are thus useful as an indicator for changes in SOC concentration. In analogy to biological indicators such as the soil microbial biomass C, the relationship between the fractions and relative changes in SOC concentration are likely to depend on climate conditions. Our methodology provides an indicator for use in routine analysis of agricultural topsoils, which is capable of predicting the effects of management practices on SOC concentrations in the short to mid-term (5–10 years). [less ▲]

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See detailBiotic predictors complement models of bat and bird responses to climate and tree diversity in European forests
Barbaro, Luc; Allan, Eric; Ampoorter, Evy et al

in Proceedings of the Royal Society. Biological Sciences (2019), 286(1894), 20182193

Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may ... [more ▼]

Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature forests replicated in six European countries from Spain to Finland, to investigate the importance of biotic predictors (i.e. the abundance or activity of defoliating insects, spiders, earthworms and wild ungulates) for bat and bird taxonomic and functional diversity. We found that nine out of 12 bird and bat diversity metrics were best explained when biotic factors were added to models including climate and habitat variables, with a mean gain in explained variance of 38 for birds and 15 for bats. Tree functional diversity was the most important habitat predictor for birds, while bats responded more to understorey structure. The best biotic predictors for birds were spider abundance and defoliating insect activity, while only bat functional evenness responded positively to insect herbivory. Accounting for potential biotic interactions between bats, birds and other taxa of lower trophic levels will help to understand how environmental changes along large biogeographical gradients affect higher-level predator diversity in forest ecosystems. [less ▲]

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See detailThe role of soil microbial diversity and activity in ecosystem functioning
Carnol, Monique ULiege

Scientific conference (2018, May 18)

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See detailEtude à long terme de la biogéochimie des écosystèmes forestiers (2017-2018/1)
Bosman, Bernard ULiege; Klenkenberg, Sophie ULiege; Carnol, Monique ULiege

Report (2018)

Depuis les années septante, la forêt a évolué d’une fonction surtout économique et productrice de bois vers un rôle multifonctionnel qui tient également compte des aspects écologiques, récréatifs ... [more ▼]

Depuis les années septante, la forêt a évolué d’une fonction surtout économique et productrice de bois vers un rôle multifonctionnel qui tient également compte des aspects écologiques, récréatifs, éducationnels et sociétaux. L’évolution des besoins de chacun et la prise en compte des services écosystémiques que la forêt peut nous fournir sont ainsi mis en avant. Parallèlement, le caractère non renouvelable des sols a été mis en évidence et des politiques ont été développées afin de préserver leur qualité. Une gestion forestière plus ‘durable’ se développe en tenant compte des différentes fonctions de la forêt, ainsi que de l’influence des pressions anthropiques exogènes (changement climatique, polluants…). La diversification des essences est apparue comme une possibilité de gestion pour maintenir les services écosystémiques fournis par les forêts et donc pour tendre vers une forêt plus ‘durable’. Pour mesurer l’impact de cette diversification, une bonne connaissance du fonctionnement de l’écosystème est indispensable. D’où le besoin d’outils de suivi et de diagnostic. Le développement d’indicateurs biologiques de la qualité du sol constitue actuellement une priorité de recherche sur les sols à l’échelle européenne. Lors des subventions précédentes, douze placettes intensives ont été équipées de dispositifs de collecte (72 collecteurs de pluviolessivats, 96 bougies poreuses) et les récoltes ont débutées en janvier 2013 pour les pluviolessivats et en janvier 2014 pour les bougies poreuses. Des mesures de la biomasse des arbres ont été réalisées dans les placettes d’étude intensive à Waroneu en juin 2013, 2015 et 2017 et à la Robinette en juin 2014 et 2016. Des échantillonnages de sol ont été réalisés en juin 2013, en janvier, mai et novembre 2014, en mai et décembre 2015, en novembre 2016 et en novembre 2017. Les mesures de l’évolution des concentrations et flux en éléments minéraux et en carbone organique dans les pluies, pluviolessivats, la solution du sol et l’exutoire de deux bassins versants ont été poursuivis. Ce rapport résulte d’une subvention entre le SPW et l’ULiège d’une durée de 7 mois. La structure du programme 2017-2018 pour un an était : 1. Fournir des mesures à long terme sur les concentrations et flux en éléments minéraux, carbone organique dans deux bassins versants forestiers 2. Fournir des mesures à long terme sur les indicateurs biologiques de la qualité des sols forestiers 3. Gérer la base de données 4. Evaluer l’évolution à long terme des dépôts acides et azotés 5. Analyser la variabilité spatiale et temporelle des processus biogéochimiques/indicateurs biologiques de la qualité du sol 6. Etudier la dynamique du carbone et de l’azote 7. Valoriser et disséminer les résultats des recherches Dans ce rapport nous présentons les perspectives pour l'analyse statistique de l'évolution à long terme des concentrations et des flux en éléments minéraux dans les bassins versants 4 forestiers ainsi que les résultats de la diversité fonctionnelle de l’échantillonnage des sols de novembre 2017. Résultats  L’applicabilité du test de tendance de Mann-Kendall et de l’algorithme BFAST sur des séries temporelles de 23 années de mesures dans les bassins versants de Waroneu et de la Robinette a été démontrée.  Entre 1992 et 2014, une diminution significative des concentrations en sulfates dans les pluies à découvert, les pluviolessivats sous épicéas et les eaux aux exutoires des bassins versants de Waroneu et de la Robinette a été mise en évidence et quantifiée.  Durant la même période, une diminution significative des concentrations en nitrates dans les pluies à découvert, les pluviolessivats sous épicéas et les eaux aux exutoires des bassins versants de Waroneu et de la Robinette a été observée.  Toujours sur cette période de 23 années, une augmentation significative du pH dans les pluies à découvert de la Robinette, les pluviolessivats sous épicéas et les eaux aux exutoires des bassins versants de Waroneu et de la Robinette a été montrée.  La parcelle W02 de Waroneu ne peut plus être considérée comme une parcelle sans couvert forestier et sera dorénavant nommée ‘en repousse’. Cette parcelle présente une diversité potentielle métabolique, une mesure de l’AWCD et un index de Shannon plus élevé que celle d’épicéas adultes sur sol brun acide (W05) de Waroneu. [less ▲]

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See detailEffect of drought legacy and tree species admixing on bacterial growth and soil respiration rates upon drying-rewetting in a young tree plantation
Rahman, Md Masudur ULiege; Hicks, L.C; Verheyen, K. et al

in Grenni, P.; Fernández-López, M.; Mercado-Blanco, J. (Eds.) Soil biodiversity and European woody agroecosystem. COST Action FP1305 BioLink-Linking belowground biodiversity and ecosystem function in European forests (2018, March)

Drought events are expected to increase as a consequence of climate change, which will most likely lead to increased frequency of drying-rewetting events in soils. Further, the establishment of mixed ... [more ▼]

Drought events are expected to increase as a consequence of climate change, which will most likely lead to increased frequency of drying-rewetting events in soils. Further, the establishment of mixed species forests may be an option to mitigate drought stress to plants. Bacterial growth and respiration rates exhibit two kinds of response upon drying-rewetting. The influence of drought legacy and tree species mixing on the microbial responses upon drying-rewetting remains unknown, but could play important role in terrestrial carbon balance in the context of climate change. Using soils from a young experimental plantation in Belgium, we investigated whether mixed planting (oak monoculture, and oak in combination with 1-3 other tree species) under simulated drought (~50 % precipitation reduction for 2 years) influenced soil microbial activity, biomass, community composition (PLFA) and microbial response upon drying-rewetting. Bacterial growth and respiration rates were lower in drought exposed soils, but fungal growth was unaffected. Drought legacy resulted in a higher fungal-to-bacterial growth ratio in the one and two tree species mixtures, but no difference in the three and four tree species mixtures. Microbial biomass was consistently lower in drought-exposed soils compared to ambient controls with no effect of tree species admixing. Upon drying-rewetting, all soils exhibited similar growth and respiration patterns with lower bacterial growth and respiration rates in drought legacy soils. Tree species mixing did not influence bacterial growth rates, but the respiration rates were higher in four tree species mixtures between 18-30 hours after drying-rewetting. Overall, our findings demonstrate that drought can have lasting effects on microbial biomass, with consequences for microbial function. Results suggest that tree species admixing to oak may alleviate the drought legacy effect on fungal:bacterial ratio, but does not modulate the bacterial growth and respiration rates upon drying-rewetting. [less ▲]

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See detailCARBIOSOL 4 - Développement d'indicateurs de la qualité biologique et du carbone organique du sol pour l'évaluation de l'état des sols en Wallonie
Krüger, Inken ULiege; Chartin, Caroline; Carnol, Monique ULiege et al

Report (2018)

The CARBIOSOL project’s aim is to develop tools for the assessment of soil quality of agricultural sites in Wallonia. It is financed by the SPW-DGO3. In its fourth part, CARBIOSOL’s main focus lays on the ... [more ▼]

The CARBIOSOL project’s aim is to develop tools for the assessment of soil quality of agricultural sites in Wallonia. It is financed by the SPW-DGO3. In its fourth part, CARBIOSOL’s main focus lays on the assessment of four agricultural practices and their impact on soil quality measured through biological indicators and carbon fractions as well as the development of analytical and cartographic tools. Six of eight biological indicators (earthworm abundance, microbial biomass, potential respiration, metabolic potential, metabolic quotient, and microbial quotient) showed significant differences between the considered agricultural practices (conventional agriculture, conservation agriculture, conversion to organic agriculture, and organic agriculture). Further, differences in the fractions of C were shown to be related to the time since practice change, highlighting the fractions advantages over total organic carbon. The changes in the stable fine fraction (C<20μm) appeared slower than those in the labile coarse fraction (C>20μm). Calculation of ratios (coarse fraction/total organic carbon) can provide information on the recent carbon evolution. Measurement of carbon fractions might be provided by agricultural laboratories in the near future, as the required material is mostly already available. Routine measurements of biological indicators by agricultural laboratories requires additional efforts to guarantee the quality of the measurements and to develop an adequate presentation of the results. Calculated ranges, taking into account both spatial and seasonal variability (measured in CARBIOSOL II and III) can serve for a first assessment of soil quality when no control sites are available. To provide further information to laboratories, a brochure that documents the challenges of soil quality and the available measurements is currently edited. Various analytical and cartographic tools were developed to optimise the use and understanding of the soil quality indicators by the future users, e.g. agricultural laboratories, farmers or public services. These tools focus on two main spatial scales of analyses, the field and the administrative region of Wallonia. [less ▲]

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See detailFORBIO Climate: Adaptation potential of biodiverse forests in the face of climate change
Ampoorter, Evy; Delvaux, Charles; De Troch, Rozemien et al

Report (2018)

Climate change is expected to have a large impact on the distribution, composition and functioning of forest ecosystems worldwide due to the limited migration and adaptation potential of trees. Creating ... [more ▼]

Climate change is expected to have a large impact on the distribution, composition and functioning of forest ecosystems worldwide due to the limited migration and adaptation potential of trees. Creating resistant and resilient forests is thus a key challenge for forest management. It has been suggested that epigenetic mechanisms may increase the capacity of trees to survive in a changing environment, but the extent and importance of these mechanisms in seedlings and saplings are still unknown. Research has also shown that more biodiverse ecosystems are better buffered against disturbances. Yet, these studies were predominantly performed in grasslands. More insight into the adaptive capacity of trees and forests in their consecutive life and development stages, respectively, and the potential buffering effect of tree species admixing to climate change is thus urgently needed. FORBIO Climate aimed at scrutinizing the adaptive capacity of particular tree species and predicting the future performance of these tree species under climate change in Belgium. The project focused on oak (Quercus robur/petraea) and beech (Fagus sylvatica), two tree species with high ecological and economic significance in Belgium (and Europe). FORBIO Climate capitalized upon multiple research infrastructures in Belgium and abroad (e.g. the FORBIO site in Zedelgem, the Belgian Observational Biodiversity Platform, the ORPHEE experiment in France, common gardens in Belgium and Denmark) to test the following hypotheses: (1) epigenetic inheritance mechanisms can increase the adaptive capacity of trees to climate change during the reproduction stage; (2) across subsequent tree development stages, tree performance is more resistant and resilient to climate change in more biodiverse forests. The project was structured in five work packages (WPs). In short, WP1 provided past climate data that were linked to the measurements on seedlings, saplings and mature trees in WP2-4 to assess the effects of climate variation on tree performance. WP1 also provided simulations of the future climate. In WP5, drought and diversity responses were scaled up to a national level and stakeholders were inquired about their perception of climate change effects and adaptation. In more detail, WP1 provided past and future climate data from selected weather stations and high-resolution Regional Climate models, respectively. Observational data from the Belgian climatological network for the period 1980-2016 were first subjected to quality control tests. Kriging using the topography as drift, and ordinary kriging were then used to interpolate the observational data on daily temperature and precipitation, respectively, on a regular 4x4 km grid over Belgium, resulting in the observational climate dataset. For the climate simulations, the Regional Climate Model ALARO-0 was used with a downscaling approach where atmosphere and land surface were modelled in a continuous way. First, the model was validated for the present climate conditions (1980-2010) by dynamical downscaling of a global climate model dataset at 4x4 km resolution. For the historical simulation (1976-2005), a constant value for the CO2-equivalent was used; for the future simulation (2007-2100), the so-called Representative Concentration Pathways (RCP 2.6, 4.5 and 8.5) were implemented, which describe the radiative forcing from greenhouse gasses, i.e. the difference between insolation (sunlight) absorbed by the Earth and the energy radiated back to space. Climate change was then calculated as the difference between the historical and the RCP simulations. The model predictions indicated a consistent T increase of 0.3 to 4.2 °C, dependent on the RCP scenario, with a larger warming for the Ardennes compared to the rest of the country. Mean annual precipitation showed a slight increase by the end of the century due to more extreme precipitation events, especially in winter and autumn. Wind speed did not change in a clear way while relative humidity showed an indistinct but consistent decrease towards the end of the century. The aim of WP2 was to quantify the epigenetic effects of parental temperature on seedling performance, using various warming treatments (soil warming, branch warming, translocation to common gardens). Parental temperature influenced the germination success, bud phenology and growth of the seedlings and this effect depended on the environmental conditions in the offspring generation. Hence, there is a need to consider the life history and parental environmental conditions to predict the response of trees to climate change. We also investigated DNA methylation as a potential epigenetic mechanism for transgenerational effects. We used Methylation Sensitive Amplified Fragment Length Polymorphism (MSAP) analysis to examine the natural variation in genome-wide DNA methylation patterns within individuals plants of a single poplar hybrid clone (genotype). However, we could not confirm that methylation helps to explain the phenological changes mediated by the parental temperature. Further investigation is necessary using more powerful molecular methods like whole-genome bisulphite sequencing techniques. WP3 quantified the impact of tree diversity and composition on the overall performance of oak and beech saplings and on the mitigation of drought stress. For this purpose, a drought experiment using rainout shelters was installed on the FORBIO-site in Zedelgem, examining the impact on sapling growth and vitality, abiotic soil variables, soil microorganisms and soil organic matter transformation. Overall, a 2-year 50% precipitation reduction did not affect tree growth but influenced soil biogeochemical processes, which could alter nutrient availability for trees in the long term. Several soil processes and microbial composition were affected by tree species admixing. This indicates that, in young forest stands, belowground processes might be more sensitive to drought and tree diversity than aboveground processes. Tree species admixing to oak and beech showed some degree of stabilizing effects against drought. WP4 examined the performance of mature oak and beech trees under drought stress and quantified the contribution of tree diversity to the mitigation of adverse climate effects on mature tree growth. We selected triplets of oak and beech and cored dominant trees to measure the ring widths. Tree ring measurements were used to test whether mixing had an impact on individual tree growth, more specifically on the sensitivity of growth to stresses like drought. On a subset of the cores, the rings of 2001, with a normal summer, and 2003, with a very dry summer, were analyzed for 12C and 13C content, from which δ^13 C was calculated, which is a measure for the extent to which the drought was experienced by the tree. Dendrometric measurements on the surrounding trees were used to characterize the neighbourhood of the trees in terms of competition and species composition. In mixed oak-beech stands, beech grew faster compared to its monocultures. However, a drawback of fast growth is the need for more water, which might cause them drying out the soil quicker. Yet, we have shown that mixing is de facto beneficial for the growth of beech trees in tough years (i.e., years of slow growth), regardless of whether this is caused by droughts or other environmental factors. Thus, the overall effect of tree diversity on the productivity of mixed beech stands remains positive. Oak, on the other hand, generally grew more slowly when mixed with beech, because beech is a better competitor. However, this disadvantage for oak became smaller in harsher conditions, and may even be reversed, for example on dry sites. In these cases, oak growth actually benefits from growing in a mixture with beech. This also means that, when conditions harshen, oak growth will be less affected in mixtures than in monocultures. In this sense, mixing can be seen as a safety measure for both oak and beech. An important output of this work package is the establishment of a network of eight oak-beech triplets, together with a collection of data on tree growth and neighbourhood. In fact, the sites already serve as soil sampling sites for other research on species mixing in forests. WP5 acted on a more integrated level in terms of time, space and forest development stage, on the role of tree diversity in a context of climate change. In a first step, nation-wide effects of climate change on stand dynamics of beech and oak stands were investigated. Data of ICP Forests, the regional forest inventory of Flanders and Wallonia, the digital soil map of Belgium, the climate dataset obtained in WP1 and a digital terrain model were used to assess tree health and growth, to examine whether drought resilience was correlated with tree diversity and whether mixed-species stands can overyield monospecific stands. Crown defoliation of beech and oak has significantly increased since the 1990s. The severity of defoliation was lower at higher tree diversity levels when considering long-term responses to changes in temperature and precipitation. The observed shift from a negative to a positive effect of species richness on forest condition, caused by increased water stress, has never been reported from real ecosystems outside experimental conditions. Drought also caused a marked growth reduction in deciduous trees, especially for beech, although we found that trees growing in mixtures were more resilient to drought than those growing in monocultures. Second, a questionnaire was administered to inform on the perception of forest owners and managers on the vulnerability of forests to climate change and the extent to which specific actions to enhance the resilience of forests are being implemented in practice. We found that there is a marked imbalance between the large awareness about climate change impacts and the adaptation practices put in place by forest managers for coping with it, probably due to a lack of locally relevant and practical information. Third, a systematic review of the published literature on tree diversity effects in a climate change context is still ongoing. Our results corroborate evidence that managing oak and beech forests to retain or increase tree diversity is a step forward to mitigate the vulnerability of these forests to climate change. Mixed stands grant managers with more options for future stand development, as they decrease the vulnerability posed on monocultures in light of future climate changes. Standardized, long-term monitoring of forest vitality is an effective method to detect climate change-induced and tree diversity-mediated trends in forest health and productivity. The continuous improvement in the quality of data that has been achieved so far has proven to be an effort that merits improved and extended continuation. Further research may focus on a wider range of tree species and multiple climate change drivers across various ecosystems to predict the response of trees to climate change better. [less ▲]

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See detaildi-Cysteine motifs in the C-terminus of plant HMA4 proteins confer nanomolar affinity for zinc and are essential for HMA4 function in vivo.
Lekeux, Gilles ULiege; Laurent, Clémentine ULiege; Joris, Marine ULiege et al

in Journal of Experimental Botany (2018), 69(22), 5547-5560

The PIB ATPase heavy metal ATPase 4 (HMA4) has a central role in the zinc homeostasis network of Arabidopsis thaliana. This membrane protein loads metal from the pericycle cells into the xylem in roots ... [more ▼]

The PIB ATPase heavy metal ATPase 4 (HMA4) has a central role in the zinc homeostasis network of Arabidopsis thaliana. This membrane protein loads metal from the pericycle cells into the xylem in roots, thereby allowing root to shoot metal translocation. Moreover, HMA4 is key for zinc hyperaccumulation as well as zinc and cadmium hypertolerance in the pseudometallophyte Arabidopsis halleri. The plant-specific cytosolic C-terminal extension of HMA4 is rich in putative metal-binding residues and has substantially diverged between A. thaliana and A. halleri. To clarify the function of the domain in both species, protein variants with truncated C-terminal extension, as well as with mutated di-Cys motifs and/or a His-stretch, were functionally characterized. We show that di-Cys motifs, but not the His-stretch, contribute to high affinity zinc binding and function in planta. We suggest that the HMA4 C-terminal extension is at least partly responsible for protein targeting to the plasma membrane. Finally, we reveal that the C-terminal extensions of both A. thaliana and A. halleri HMA4 proteins share similar function, despite marginally different zinc-binding capacity. [less ▲]

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See detailMiscanthus Biochar had Limited Effects on Soil Physical Properties, Microbial Biomass, and Grain Yield in a Four-Year Field Experiment in Norway
O'Toole, Adam; Moni, Christophe; Weldon, Simon et al

in Agriculture (2018), 8(11), 171-190

he application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its ... [more ▼]

he application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its utility to improve plant growth and soil quality. In this context, we conducted a four-year field experiment between October 2010 to October 2014 on a fertile silty clay loam Albeluvisol in Norway to assess the impact of biochar on soil physical properties, soil microbial biomass, and oat and barley yield. The following treatments were included: Control (soil), miscanthus biochar 8 t C ha−1 (BC8), miscanthus straw feedstock 8 t C ha−1 (MC8), and miscanthus biochar 25 t C ha−1 (BC25). Average volumetric water content at field capacity was significantly higher in BC25 when compared to the control due to changes in BD and total porosity. The biochar amendment had no effect on soil aggregate (2–6 mm) stability, pore size distribution, penetration resistance, soil microbial biomass C and N, and basal respiration. Biochar did not alter crop yields of oat and barley during the four growing seasons. In order to realize biochar’s climate mitigation potential, we suggest future research and development efforts should focus on improving the agronomic utility of biochar in engineered fertilizer and soil amendment products. [less ▲]

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See detailCan tree species richness attenuate the effect of drought on organic matter decomposition and stabilization in young plantation forests?
Rahman, Md Masudur ULiege; Castagneyrol, Bastien; Verheyen, Kris et al

in Acta Oecologica (2018), 93

Changes in precipitation due to climate change are likely to influence soil organic matter (SOM) decomposition and stabilization. In forests, increased tree species diversity could modulate the effects of ... [more ▼]

Changes in precipitation due to climate change are likely to influence soil organic matter (SOM) decomposition and stabilization. In forests, increased tree species diversity could modulate the effects of drought on SOM decomposition and stabilization. We addressed this issue by a decomposition study under simulated drought (through precipitation reduction at Zedelgem, Belgium) and natural drought (ORPHEE, southern France) in young experimental plantations (tree species richness 1 to 5). In Zedelgem, the study focused on tree species richness around oak and beech trees. Two tea bag indices (TBI) – decomposition rate (k) and stabilization factor (S) – were calculated by measuring the decay of green and rooibos tea in soils. Overall, TBI's were higher in Zedelgem than at ORPHEE. In Zedelgem, k increased with tree species richness under drought around oak, indicating that tree species richness modulated the effects of drought on decomposition. Under beech, k de- creased with drought while no effect of tree species richness was detected. S increased with drought under both oak and beech, without any effect of tree species richness. In ORPHEE, we did not detect any tree species richness effect on both TBIs. S decreased significantly, while k was marginally reduced under drought. The higher S under drought in Zedelgem and under control in OPRHEE suggests that the carbon sequestration po- tential under climate change would be dependent on the environmental context. Further, in young plantations, high species richness may modulate the drought effect on SOM decomposition, but not on stabilization. [less ▲]

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See detailEffects of drought legacy and tree species admixing on bacterial growth and respiration in a young forest soil upon drying and rewetting
Rahman, Md Masudur ULiege; Hicks, Lettice C.; Verheyen, Kris et al

in Soil Biology and Biochemistry (2018), 127

In the context of future climate change, the flush of CO2 emissions from soils after drying-rewetting events could have a strong impact on the terrestrial carbon balance. Mixed forests may be more ... [more ▼]

In the context of future climate change, the flush of CO2 emissions from soils after drying-rewetting events could have a strong impact on the terrestrial carbon balance. Mixed forests may be more resistant and resilient to drought events compared to monocultures, and as such may modulate the effects of drought on soil functioning belowground. We investigated the influence of mixed planting and drought legacy on respiration and bacterial growth rates (3H Leucine incorporation) in response to drying-rewetting. Soils were sampled from a 7-year old tree diversity experiment (FORBIO), where oak (Quercus robur L.) trees admixed with one or three other tree species were subjected to ∼50% precipitation reduction for 2 years (“drought legacy”). Respiration increased immediately after rewetting, whereas bacterial growth only started after a distinct lag phase of ca. 7 h. A legacy of drought reduced bacterial growth and respiration rates upon rewetting, however tree species admixing did not modulate the drought legacy effect. Our results suggest that prolonged decrease in precipitation may lead to a reduced CO2 pulse upon drying-rewetting and admixing up to three tree species with oak in a young afforestation would not alleviate drought legacy effects on bacterial growth and respiration rates. [less ▲]

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See detailDefining a reference system for biological indicators of agricultural soil quality in Wallonia, Belgium
Krüger, Inken Betty; Chartin, Caroline; van Wesemael, Bas et al

in Ecological Indicators (2018), 95

Tools that will enable the assessment of agricultural soil quality and include measurements of biological indicators, such as soil respiration or N mineralization, are increasingly in demand. Such tools ... [more ▼]

Tools that will enable the assessment of agricultural soil quality and include measurements of biological indicators, such as soil respiration or N mineralization, are increasingly in demand. Such tools require the establishment of reference systems to provide comparative ‘baseline’ or ‘normal’ values. In this study, we measured the spatial and seasonal variability of eight biological indicators (including two eco-physiological quotients) in order to establish a reference system at the regional level of Wallonia (Southern Belgium). Respiration potential, microbial biomass carbon, microbial C/N ratio, net nitrogen mineralisation, metabolic potential of soil bacteria, earthworm abundance, microbial quotient, and metabolic quotient were measured at 60 sites across contrasting agricultural regions (different soil types and climate) in both grasslands and croplands. Additionally, the same biological indicators were measured four times during the vegetation period (April, June, August, and October) in 11 cropland sites to assess seasonal variability. Reference ranges were defined for each biological indicator, based on the addition of variances (seasonal and spatial) and the calculation of cumulative distribution functions. Land use was the most useful classification variable to define a reference system in Wallonia. Two separate reference systems, one for grasslands and one for croplands, were thus appropriate for Wallonia. Sampling season had a significant effect on all biological indicators. The inclusion of seasonal variability resulted in reference ranges 1.1 to 5.7 times wider than ranges accounting only for spatial variability. The reference system provides a basis for a first comparative assessment of soil quality for most agricultural soils of Wallonia, independent of sampling period. [less ▲]

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See detailThe legacy of mixed planting and precipitation reduction treatments on soil microbial activity, biomass and community composition in a young tree plantation
Hicks, L. C.; Rahman, Md Masudur ULiege; Carnol, Monique ULiege et al

in Soil Biology and Biochemistry (2018), 124

Drought events are expected to increase as a consequence of climate change, with the potential to influence both plant and soil microbial communities. Mixed planting may be an option to mitigate drought ... [more ▼]

Drought events are expected to increase as a consequence of climate change, with the potential to influence both plant and soil microbial communities. Mixed planting may be an option to mitigate drought stress to plants, however, the extent to which mixed planting mitigates the indirect effect of drought (reduced plant-derived carbon input) on soil microorganisms remains unknown. Using soils from a young experimental plantation in Central Europe, we investigated whether mixed planting (oak monoculture, and oak admixed with 1–3 other tree species) under simulated drought (50% precipitation reduction for 2 years) influenced soil microbial activity, biomass and community composition. To focus on legacy effects - i.e. indirect effects mediated by plant composition and a history of drought, rather than direct effects of reduced water availability - soils were measured at a standardised moisture content (28±1% water holding capacity). Rates of bacterial growth and respiration were lower in soils with a legacy of drought. In contrast, fungal growth was not affected by a history of drought, suggesting that fungi were less adversely affected by reduced plant-input during drought, compared to bacteria. The effect of drought on the fungal-to-bacterial growth ratio was influenced by mixed planting, leading to a disproportionate decrease in bacterial growth in drought-exposed soils under oak monoculture than when oak was admixed with two or three different tree species. The presence of a particular tree species (with specific functional traits) in the admixture, rather than increased tree richness per se, may explain this response. Microbial biomass parameters, reflecting both the direct and indirect effects of past drought conditions, were consistently lower in drought-exposed soils than controls. While bacteria were more sensitive to the indirect effect of drought than fungi, the biomass concentrations suggested that the direct effect of reduced moisture affected both groups similarly. Overall, our findings demonstrate that drought can have lasting effects on microbial communities, with consequences for microbial function. Results also suggest that admixing oak with other tree species may alleviate the drought-legacy effect on bacteria and increase tolerance to future drought. [less ▲]

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See detailEarly stage litter decomposition across biomes
Djukic, I.; Kepfer-Rojas, S.; Schmidt, I. K. et al

in Science of the Total Environment (2018), 628-629

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order ... [more ▼]

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and metaanalyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from −9 to +26 °C MAT and from 60 to 3113mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained b0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments).When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea).No significant effect of land-use on early stage litter decompositionwas notedwithin the temperate biome. Our results indicate that multiple drivers are affecting early stage littermass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed. [less ▲]

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See detailHigh-throughput Sequencing Analysis of the Actinobacterial Spatial Diversity in Moonmilk Deposits
Maciejewska, M; Całusińska; Cornet, Luc ULiege et al

in Antibiotics (2018), 7(2)(28),

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