| 1. |
- Meisner, Annelein, et al.
(author)
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Soil biotic legacy effects of extreme weather events influence plant invasiveness
- 2013
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In: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 110:24, s. 9835-9838
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Journal article (peer-reviewed)abstract
- Climate change is expected to increase future abiotic stresses on ecosystems through extreme weather events leading to more extreme drought and rainfall incidences [Jentsch A, et al. (2007) Front Ecol Environ 5(7): 365-374]. These fluctuations in precipitation may affect soil biota, soil processes [Evans ST, Wallenstein MD (2012) Biogeochemistry 109: 101-116], and the proportion of exotics in invaded plant communities [Jimenez MA, et al. (2011) Ecol Lett 14: 1277-1235]. However, little is known about legacy effects in soil on the performance of exotics and natives in invaded plant communities. Here we report that drought and rainfall effects on soil processes and biota affect the performance of exotics and natives in plant communities. We performed two mesocosm experiments. In the first experiment, soil without plants was exposed to drought and/or rainfall, which affected soil N availability. Then the initial soil moisture conditions were restored, and a mixed community of co-occurring natives and exotics was planted and exposed to drought during growth. A single stress before or during growth decreased the biomass of natives, but did not affect exotics. A second drought stress during plant growth resetted the exotic advantage, whereas native biomass was not further reduced. In the second experiment, soil inoculation revealed that drought and/or rainfall influenced soil biotic legacies, which promoted exotics but suppressed natives. Our results demonstrate that extreme weather events can cause legacy effects in soil biota, promoting exotics and suppressing natives in invaded plant communities, depending on the type, frequency, and timing of extreme events.
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| 2. |
- García-Palacios, Pablo, et al.
(author)
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Crop traits drive soil carbon sequestration under organic farming
- 2018
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In: Journal of Applied Ecology. - Chichester : Wiley. - 0021-8901 .- 1365-2664. ; 55:5, s. 2496-2505
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Journal article (peer-reviewed)abstract
- Organic farming (OF) enhances top soil organic carbon (SOC) stocks in croplands compared with conventional farming (CF), which can contribute to sequester C. As farming system differences in the amount of C inputs to soil (e.g. fertilization and crop residues) are not enough to explain such increase, shifts in crop residue traits important for soil C losses such as litter decomposition may also play a role. To assess whether crop residue (leaf and root) traits determined SOC sequestration responses to OF, we coupled a global meta-analysis with field measurements across a European-wide network of sites. In the meta-analysis, we related crop species averages of leaf N, leaf-dry matter content, fine-root C and N, with SOC stocks and sequestration responses in OF vs. CF. Across six European sites, we measured the management-induced changes in SOC stocks and leaf litter traits after long-term ecological intensive (e.g. OF) vs. CF comparisons. Our global meta-analysis showed that the positive OF-effects on soil respiration, SOC stocks, and SOC sequestration rates were significant even in organic farms with low manure application rates. Although fertilization intensity was the main driver of OF-effects on SOC, leaf and root N concentrations also played a significant role. Across the six European sites, changes towards higher leaf litter N in CF also promoted lower SOC stocks. Our results highlight that crop species displaying traits indicative of resource-acquisitive strategies (e.g. high leaf and root N) increase the difference in SOC between OF and CF. Indeed, changes towards higher crop residue decomposability was related with decreased SOC stocks under CF across European sites. Synthesis and applications. Our study emphasizes that, with management, changes in crop residue traits contribute to the positive effects of organic farming (OF) on soil carbon sequestration. These results provide a clear message to land managers: the choice of crop species, and more importantly their functional traits (e.g. leave and root nitrogen), should be considered in addition to management practices and climate, when evaluating the potential of OF for climate change mitigation.
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| 3. |
- Hines, Jes, et al.
(author)
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Towards an integration of biodiversity-ecosystem functioning and food web theory to evaluate relationships between multiple ecosystem services
- 2015
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In: Advances in Ecological Research. - : Elsevier. - 0065-2504. ; 53, s. 161-199
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Journal article (peer-reviewed)abstract
- Ecosystem responses to changes in species diversity are often studied individually. However, changes in species diversity can simultaneously influence multiple interdependent ecosystem functions. Therefore, an important challenge is to determine when and how changes in species diversity that influence one function will also drive changes in other functions. By providing the underlying structure of species interactions, ecological networks can quantify connections between biodiversity and multiple ecosystem functions. Here, we review parallels in the conceptual development of biodiversity- ecosystem functioning (BEF) and food web theory (FWT) research. Subsequently, we evaluate three common principles that unite these two research areas by explaining the patterns, concentrations, and direction of the flux of nutrients and energy through the species in diverse interaction webs. We give examples of combined BEF-FWT approaches that can be used to identify vulnerable species and habitats and to evaluate links that drive trade-offs between multiple ecosystems functions. These combined approaches reflect promising trends towards better management of biodiversity in landscapes that provide essential ecosystem services supporting human well-being.
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| 4. |
- Manning, Peter, et al.
(author)
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Transferring biodiversity-ecosystem function research to the management of 'real-world' ecosystems
- 2019
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In: Mechanisms underlying the relationship between biodiversity and ecosystem function. - London : Elsevier. - 9780081029121 - 9780081029138 ; , s. 323-356
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Book chapter (peer-reviewed)abstract
- Biodiversity-ecosystem functioning (BEF) research grew rapidly following concerns that biodiversity loss would negatively affect ecosystem functions and the ecosystem services they underpin. However, despite evidence that biodiversity strongly affects ecosystem functioning, the influence of BEF research upon policy and the management of 'real-world' ecosystems, i.e., semi-natural habitats and agroecosystems, has been limited. Here, we address this issue by classifying BEF research into three clusters based on the degree of human control over species composition and the spatial scale, in terms of grain, of the study, and discussing how the research of each cluster is best suited to inform particular fields of ecosystem management. Research in the first cluster, small-grain highly controlled studies, is best able to provide general insights into mechanisms and to inform the management of species-poor and highly managed systems such as croplands, plantations, and the restoration of heavily degraded ecosystems. Research from the second cluster, small-grain observational studies, and species removal and addition studies, may allow for direct predictions of the impacts of species loss in specific semi-natural ecosystems. Research in the third cluster, large-grain uncontrolled studies, may best inform landscape-scale management and national-scale policy. We discuss barriers to transfer within each cluster and suggest how new research and knowledge exchange mechanisms may overcome these challenges. To meet the potential for BEF research to address global challenges, we recommend transdisciplinary research that goes beyond these current clusters and considers the social-ecological context of the ecosystems in which BEF knowledge is generated. This requires recognizing the social and economic value of biodiversity for ecosystem services at scales, and in units, that matter to land managers and policy makers.
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| 5. |
- Martínez-García, Laura B., et al.
(author)
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Organic management and cover crop species steer soil microbial community structure and functionality along with soil organic matter properties
- 2018
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In: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809. ; 263, s. 7-17
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Journal article (peer-reviewed)abstract
- It is well recognized that organic soil management stimulates bacterial biomass and activity and that including cover crops in the rotation increases soil organic matter (SOM). Yet, to date the relative impact of different cover crop species and organic vs. non-organic soil management on soil bacteria and fungi and on SOM quantity and quality remains to be tested. We used a long-term (10 years) full-factorial field experiment to test the combined effects of organic vs. conventional soil management with different cover crop species (oat or rye) and the legacy effects of seven soil health treatments (SHTs: treatments with compost, chitin, marigold, grass–clover, biofumigation or anaerobic soil disinfestation (ASD), and fallow as control) on microbial community biomass, structure and catabolic activity and on SOM quantity and quality (dissolved organic carbon (DOC), aromaticity and water repellency). Microbial community traits were assessed using PLFA/NLFA analyses and multi-substrate induced respiration. We found that organic soil management enhanced total microbial biomass by increasing bacterial, saprotrophic and arbuscular mycorrhizal fungal biomass; and increased total microbial catabolic activity, associated with maintaining high microbial efficiency (low qCO2). Effects of organic management were amplified by oat as cover crop, which enhanced the abundance of saprotrophic fungi resulting in a higher fungal:bacterial ratio. Total SOM concentration was similar among treatments, however the most easily accessible fraction, i.e. DOC, was higher in organic compared to conventional soils. Also, the aromaticity of the DOC was lower in organic than in conventional systems, which was associated with lower water repellency. There was a legacy effect of SHTs on fungal:bacterial ratio in that chitin and marigold showed higher fungal:bacterial ratio compared to compost, biofumigation and ASD even 6 years after the last application. We conclude that organic soil management enhances the abundance of all microbial groups and their total catabolic activity, associated with a higher concentration and lower aromaticity of dissolved organic matter. These effects can be enlarged by the growth of specific cover crops and the application of certain soil health treatments.
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| 6. |
- Piton, Gabin, et al.
(author)
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Disentangling drivers of soil microbial potential enzyme activity across rain regimes : An approach based on the functional trait framework
- 2020
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In: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717. ; 148
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Journal article (peer-reviewed)abstract
- The functional trait framework provides a powerful corpus of integrated concepts and theories to assess how environmental factors influence ecosystem functioning through community assembly. While common in plant ecology, this approach is under-used in microbial ecology. After an introduction of this framework in the context of microbial ecology and enzymology, we propose an approach 1) to elucidate new links between soil microbial community composition and microbial traits; and 2) to disentangle mechanisms underlying “total” potential enzyme activity in soil (sum of 7 hydrolase potential activities). We address these objectives using a terrestrial grassland ecosystem model experiment with intact soil monoliths from three European countries (Switzerland, France and Portugal) and two management types (Conventional-intensive and Ecological-intensive), subjected to 4 rain regimes (Dry, Wet, Intermittent and Normal) under controlled conditions in a common climate chamber. We found tight associations between proxies of microbial ecoenzymatic community-weighted mean traits (enzymatic stoichiometry and biomass-specific activity) and community composition, bringing new information on resource acquisition strategy associated with fungi, Gram positive and Gram negative bacteria. We demonstrate that microbial biomass explained most of the total enzyme activity before altered rain regimes, whereas adjustments in biomass-specific activity (enzyme activity per unit of microbial biomass) explained most variation under altered rain regime scenarios. Furthermore, structural equation models revealed that the variation of community composition was the main driver of the variation in biomass-specific enzyme activity prior to rain perturbation, whereas physiological acclimation or evolutionary adaptation became an important driver only under altered rain regimes. This study presents a promising trait-based approach to investigate soil microbial community response to environmental changes and potential consequences for ecosystem functioning. We argue that the functional trait framework should be further implemented in microbial ecology to guide experimental and analytical design.
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| 7. |
- Piton, Gabin, et al.
(author)
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Resistance–recovery trade-off of soil microbial communities under altered rain regimes : An experimental test across European agroecosystems
- 2021
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In: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 58:2, s. 406-418
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Journal article (peer-reviewed)abstract
- With the increased occurrence of climate extremes, there is an urgent need to better understand how management strategies affect the capacity of the soil microbial community to maintain its ecosystem functions (e.g. nutrient cycling). To address this issue, intact monoliths were extracted from conventional and ecological managed grasslands in three countries across Europe and exposed under common air condition (temperature and moisture) to one of three altered rain regimes (dry, wet and intermittent wet/dry) as compared to a normal regime. Subsequently, we compared the resistance and recovery of the soil microbial biomass, potential enzyme activities and community composition. The microbial community composition differed with soil management and rain regimes. Soil microbial biomass increased from the wetter to the dryer rain regime, paralleling an increase of available carbon and nutrients, suggesting low sensitivity to soil moisture reduction but nutritional limitations of soil microbes. Conversely, enzyme activities decreased with all altered rain regimes. Resistance and recovery (considering absolute distance between normal and altered rain regime) of the microbial communities depended on soil management. Conventional-intensive management showed higher resistance of two fundamental properties for nutrient cycling (i.e. bacterial biomass and extracellular enzyme activities) yet associated with more important changes in microbial community composition. This suggests an internal community reorganization promoting biomass and activity resistance. Conversely, under ecological management bacterial biomass and enzyme activities showed better recovery capacity, whereas no or very low recovery of these properties was observed under conventional management. These management effects were consistent across the three altered rain regimes investigated, indicating common factors controlling microbial communities’ response to different climate-related stresses. Synthesis and applications. Our study provides experimental evidence for an important trade-off for agroecosystem management between (a) stabilizing nutrient cycling potential during an altered rain regime period at the expense of very low recovery capacity and potential long-term effect (conventional sites) and (b) promoting the capacity of the microbial community to recover its functional potential after the end of the stress (ecological sites). Thus, management based on ecologically sound principles may be the best option to sustain long-term soil functioning under climate change.
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