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| 2. |
- Bommarco, Riccardo, et al.
(author)
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Exploiting ecosystem services in agriculture for increased food security
- 2018
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In: Global Food Security. - : Elsevier BV. - 2211-9124. ; 17, s. 57-63
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Research review (peer-reviewed)abstract
- Despite contributing to economy and food security, Ecosystem Services (ES) are still not fully exploited in agriculture. Instead, external inputs have been used to boost yields, while exacting costs on public goods. Ecological intensification capitalizes on ecosystem services to enhance and stabilize production and reduce the need for external inputs, while sparing the environment. Of particular relevance are biodiversity-based ES connected to soil fertility, pest control and pollination. Ecological intensification is applicable in all regions, but for food security purposes, particular attention should be dedicated to implement it as ecological enhancement in regions with wide yield gaps, coinciding with poor food security. Diversified cropping system show promise to create win-win situations. Knowledge on ecology and socio-economy of ES will be needed, and agricultural research and innovation need to heed to resource use efficiency, production stability, minimal environmental impact, buffering of extreme events and adaptation to local conditions.
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| 3. |
- Breinl, Korbinian, et al.
(author)
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Can weather generation capture precipitation patterns across different climates, spatial scales and under data scarcity?
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Journal article (peer-reviewed)abstract
- Stochastic weather generators can generate very long time series of weather patterns, which are indispensable in earth sciences, ecology and climate research. Yet, both their potential and limitations remain largely unclear because past research has typically focused on eclectic case studies at small spatial scales in temperate climates. In addition, stochastic multi-site algorithms are usually not publicly available, making the reproducibility of results difficult. To overcome these limitations, we investigated the performance of the reduced-complexity multi-site precipitation generator TripleM across three different climatic regions in the United States. By resampling observations, we investigated for the first time the performance of a multi-site precipitation generator as a function of the extent of the gauge network and the network density. The definition of the role of the network density provides new insights into the applicability in data-poor contexts. The performance was assessed using nine different statistical metrics with main focus on the inter-annual variability of precipitation and the lengths of dry and wet spells. Among our study regions, our results indicate a more accurate performance in wet temperate climates compared to drier climates. Performance deficits are more marked at larger spatial scales due to the increasing heterogeneity of climatic conditions.
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| 4. |
- Feng, Xue, et al.
(author)
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Beyond isohydricity : The role of environmental variability in determining plant drought responses
- 2019
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In: Plant, Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 42:4, s. 1104-1111
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Journal article (peer-reviewed)abstract
- Despite the appeal of the iso/anisohydric framework for classifying plant drought responses, recent studies have shown that such classifications can be strongly affected by a plant's environment. Here, we present measured in situ drought responses to demonstrate that apparent isohydricity can be conflated with environmental conditions that vary over space and time. In particular, we (a) use data from an oak species (Quercus douglasii) during the 2012-2015 extreme drought in California to demonstrate how temporal and spatial variability in the environment can influence plant water potential dynamics, masking the role of traits; (b) explain how these environmental variations might arise from climatic, topographic, and edaphic variability; (c) illustrate, through a common garden thought experiment, how existing trait-based or response-based isohydricity metrics can be confounded by these environmental variations, leading to Type-1 (false positive) and Type-2 (false negative) errors; and (d) advocate for the use of model-based approaches for formulating alternate classification schemes. Building on recent insights from greenhouse and vineyard studies, we offer additional evidence across multiple field sites to demonstrate the importance of spatial and temporal drivers of plants' apparent isohydricity. This evidence challenges the use of isohydricity indices, per se, to characterize plant water relations at the global scale.
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| 5. |
- Feng, Xue, et al.
(author)
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The ecohydrological context of drought and classification of plant responses
- 2018
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In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 21:11, s. 1723-1736
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Research review (peer-reviewed)abstract
- Many recent studies on drought‐induced vegetation mortality have explored how plant functional traits, and classifications of such traits along axes of, for example, isohydry–anisohydry, might contribute to predicting drought survival and recovery. As these studies proliferate, the consistency and predictive value of such classifications need to be carefully examined. Here, we outline the basis for a systematic classification of plant drought responses that accounts for both environmental conditions and functional traits. We use non‐dimensional analysis to integrate plant traits and metrics of environmental variation into groups that can be associated with alternative drought stress pathways (hydraulic failure and carbon limitation), and demonstrate that these groupings predict physiological drought outcomes using both synthetic and measured data. In doing so, we aim to untangle some confounding effects of environment and trait variations that undermine current classification schemes, advocate for more careful treatment of the environmental context within which plants experience and respond to drought, and outline a pathway towards a general classification of drought vulnerability.
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| 7. |
- Livsey, John, et al.
(author)
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Do alternative irrigation strategies for rice cultivation decrease water footprints at the cost of long-term soil health?
- 2019
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In: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 14:7
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Journal article (peer-reviewed)abstract
- The availability of water is a growing concern for flooded rice production. As such, several water-saving irrigation practices have been developed to reduce water requirements. Alternate wetting and drying and mid-season drainage have been shown to potentially reduce water requirements while maintaining rice yields when compared to continuous flooding. With the removal of permanently anaerobic conditions during the growing season, water-saving irrigation can also reduce CO2 equivalent (CO2eq) emissions, helping reduce the impact of greenhouse gas (GHG) emissions. However, the long-term impact of water-saving irrigation on soil organic carbon (SOC)-used here as an indicator of soil health and fertility-has not been explored. We therefore conducted a meta-analysis to assess the effects of common water-saving irrigation practices (alternate wetting and drying and mid-season drainage) on (i) SOC, and (ii) GHG emissions. Despite an extensive literature search, only 12 studies were found containing data to constrain the soil C balance in both continuous flooding and water-saving irrigation plots, highlighting the still limited understanding of long-term impacts of water-saving irrigation on soil health and GHG emissions. Water-saving irrigation was found to reduce emissions of CH4 by 52.3% and increased those of CO2 by 44.8%. CO2eq emissions were thereby reduced by 18.6% but the soil-to-atmosphere carbon (C) flux increased by 25% when compared to continuous flooding. Water-saving irrigation was also found to have a negative effect on both SOC-reducing concentrations by 5.2%-and soil organic nitrogen-potentially depleting stocks by more than 100 kgN/ha per year. While negative effects of water-saving irrigation on rice yield may not be visible in short-term experiments, care should be taken when assessing the long-term sustainability of these irrigation practices because they can decrease soil fertility. Strategies need to be developed for assessing the more long-term effects of these irrigation practices by considering trade-offs between water savings and other ecosystem services.
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| 8. |
- Manzoni, Stefano, et al.
(author)
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Contrasting leaf phenological strategies optimize carbon gain under droughts of different duration
- 2015
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In: Advances in Water Resources. - : Elsevier BV. - 0309-1708 .- 1872-9657. ; 84, s. 37-51
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Journal article (peer-reviewed)abstract
- In most ecosystems, plants face periods with limited water availability, during which stomatal conductance is reduced to maintain hydration. However, prolonged dry spells might require more drastic strategies to conserve water, such as drought-deciduousness. If drought-related changes in leaf area are adaptive, it can be hypothesized that leaf area is optimized to maximize the growing-season carbon (C) gain. Different phenological strategies during drought have been proposed: (i) leaf area index (L) declines when net photosynthetic rates (A(net)) reach zero to maintain a non-negative A(net); (ii) L adjusts to avoid water potentials with negative impacts on A(net); (iii) a constant leaf water potential is maintained (isohydric behavior); and (iv) leaf area remains unaltered (i.e., summer-evergreen leaf habit). However, whether these strategies are optimal in terms of growing season C gains has not been assessed. Here we consider these theories in a unified framework using the same set of equations to describe gas exchanges and water transport in the soil plant atmosphere continuum, and quantify the effect of the leaf phenological strategy on plant C gain over the entire growing season in different climates. Longer dry periods tend to favor drought-deciduous rather than summer-evergreen habit. Deciduous plants that allow leaf water potential to fluctuate (anisohydric) while preventing negative A(net) assimilate more carbon than deciduous plants with fixed leaf water potentials (isohydric). Increased rooting depth allows evergreens to more effectively compete with drought-deciduous species. Moreover, increasing leaf nitrogen concentrations and thus photosynthetic capacity can be an effective acclimation strategy when dry periods are relatively short.
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| 9. |
- Manzoni, Stefano, et al.
(author)
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Reviews and syntheses : Carbon use efficiency from organisms to ecosystems - definitions, theories, and empirical evidence
- 2018
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In: Biogeosciences. - : COPERNICUS GESELLSCHAFT MBH. - 1726-4170 .- 1726-4189. ; 15:19, s. 5929-5949
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Research review (peer-reviewed)abstract
- The cycling of carbon (C) between the Earth surface and the atmosphere is controlled by biological and abiotic processes that regulate C storage in biogeochemical compartments and release to the atmosphere. This partitioning is quantified using various forms of C-use efficiency (CUE) - the ratio of C remaining in a system to C entering that system. Biological CUE is the fraction of C taken up allocated to biosynthesis. In soils and sediments, C storage depends also on abiotic processes, so the term C-storage efficiency (CSE) can be used. Here we first review and reconcile CUE and CSE definitions proposed for autotrophic and heterotrophic organisms and communities, food webs, whole ecosystems and watersheds, and soils and sediments using a common mathematical framework. Second, we identify general CUE patterns; for example, the actual CUE increases with improving growth conditions, and apparent CUE decreases with increasing turnover. We then synthesize > 5000CUE estimates showing that CUE decreases with increasing biological and ecological organization - from uni-cellular to multicellular organisms and from individuals to ecosystems. We conclude that CUE is an emergent property of coupled biological-abiotic systems, and it should be regarded as a flexible and scale-dependent index of the capacity of a given system to effectively retain C.
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| 10. |
- Marquardt, Kristina, et al.
(author)
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Farmer perspectives on introducing perennial cereal in Swedish farming systems: A sustainability analysis of plant traits, farm management, and ecological implications
- 2016
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In: Agroecology and Sustainable Food Systems. - : Informa UK Limited. - 2168-3565 .- 2168-3573. ; 40, s. 432-450
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Journal article (peer-reviewed)abstract
- Agriculture is currently dominated by annual crops. A shift from annual to perennial cereals has been suggested as a way to improve the sustainability of agriculture. Such a shift may have impacts at multiple levels, from the field, to the farm, and the landscape. With a focus on Swedish farm production systems, farmers' views on the potential risks and possibilities of cultivating perennial cereals are discussed in light of the available knowledge regarding plant traits and ecological implications of perennial systems. Farmer interviews showed that potential changes in agricultural sustainability, if perennial cereals were to be introduced, are highly complex, and context specific. Perennial cereals could be part of a transition toward a more sustainable agriculture depending on how they are used in the local farming system and in the larger landscape. Efforts to increase the use of perennial crops require linking specific plant traits of the perennial crop to the properties of the farming systems where these crops would be employed.
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