101
|
Thoms R, Köhler M, Gessler A, Gleixner G. Above and below ground carbohydrate allocation differs between ash (Fraxinus excelsior L.) and beech (Fagus sylvatica L.). PLoS One 2017; 12:e0184247. [PMID: 28934229 PMCID: PMC5608211 DOI: 10.1371/journal.pone.0184247] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/21/2017] [Indexed: 11/19/2022] Open
Abstract
We investigated soluble carbohydrate transport in trees that differed in their phloem loading strategies in order to better understand the transport of photosynthetic products into the roots and the rhizosphere as this knowledge is needed to better understand the respiratory processes in the rhizosphere. We compared beech, which is suggested to use mainly passive loading of transport sugars along a concentration gradient into the phloem, with ash that uses active loading and polymer trapping of raffinose family oligosaccharides (RFOs). We pulse-labeled 20 four-year old European beech and 20 four-year old ash trees with 13CO2 and tracked the fate of the label within different plant compartments. We extracted soluble carbohydrates from leaves, bark of stems and branches, and fine roots, measured their amount and isotopic content and calculated their turnover times. In beech one part of the sucrose was rapidly transported into sink tissues without major exchange with storage pools whereas another part of sucrose was strongly exchanged with unlabeled possibly stored sucrose. In contrast the storage and allocation patterns in ash depended on the identity of the transported sugars. RFO were the most important transport sugars that had highest turnover in all shoot compartments. However, the turnover of RFOs in the roots was uncoupled from the shoot. The only significant relation between sugars in the stem base and in the roots of ash was found for the amount (r2 = 0.50; p = 0.001) and isotopic content (r2 = 0.47; p = 0.01) of sucrose. The negative relation of the amounts suggested an active transport of sucrose into the roots of ash. Sucrose concentration in the root also best explained the concentration of RFOs in the roots suggesting that RFO in the roots of ash may be resynthesized from sucrose. Our results interestingly suggest that in both tree species only sucrose directly entered the fine root system and that in ash RFOs are transported indirectly into the fine roots only. The direct transport of sucrose might be passive in beech but active in ash (sustained active up- and unloading to co-cells), which would correspond to the phloem loading strategies. Our results give first hints that the transport of carbohydrates between shoot and root is not necessarily continuous and involves passive (beech) and active (ash) transport processes, which may be controlled by the phloem unloading.
Collapse
Affiliation(s)
- Ronny Thoms
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Michael Köhler
- Burckhardt-Institute, Tropical Silviculture and Forest Ecology, Göttingen, Germany
| | | | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry, Jena, Germany
| |
Collapse
|
102
|
Kaisermann A, de Vries FT, Griffiths RI, Bardgett RD. Legacy effects of drought on plant-soil feedbacks and plant-plant interactions. THE NEW PHYTOLOGIST 2017. [PMID: 28621813 DOI: 10.1111/nph.14661] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Interactions between aboveground and belowground biota have the potential to modify ecosystem responses to climate change, yet little is known about how drought influences plant-soil feedbacks with respect to microbial mediation of plant community dynamics. We tested the hypothesis that drought modifies plant-soil feedback with consequences for plant competition. We measured net pairwise plant-soil feedbacks for two grassland plant species grown in monoculture and competition in soils that had or had not been subjected to a previous drought; these were then exposed to a subsequent drought. To investigate the mechanisms involved, we assessed treatment responses of soil microbial communities and nutrient availability. We found that previous drought had a legacy effect on bacterial and fungal community composition that decreased plant growth in conspecific soils and had knock-on effects for plant competitive interactions. Moreover, plant and microbial responses to subsequent drought were dependent on a legacy effect of the previous drought on plant-soil interactions. We show that drought has lasting effects on belowground communities with consequences for plant-soil feedbacks and plant-plant interactions. This suggests that drought, which is predicted to increase in frequency with climate change, may change soil functioning and plant community composition via the modification of plant-soil feedbacks.
Collapse
Affiliation(s)
- Aurore Kaisermann
- School of Earth and Environmental Sciences, The University of Manchester, Michael Smith Building, Manchester, M13 9PT, UK
- UMR 1391 Interaction Sol-Plante-Atmosphere, INRA Centre Bordeaux-Aquitaine, CS20032, 71 Avenue Edouard Bourlaux, Villenave d'Ornon Cedex, 33882, France
| | - Franciska T de Vries
- School of Earth and Environmental Sciences, The University of Manchester, Michael Smith Building, Manchester, M13 9PT, UK
| | - Robert I Griffiths
- Centre of Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB, UK
| | - Richard D Bardgett
- School of Earth and Environmental Sciences, The University of Manchester, Michael Smith Building, Manchester, M13 9PT, UK
| |
Collapse
|
103
|
Starke R, Bastida F, Abadía J, García C, Nicolás E, Jehmlich N. Ecological and functional adaptations to water management in a semiarid agroecosystem: a soil metaproteomics approach. Sci Rep 2017; 7:10221. [PMID: 28860535 PMCID: PMC5579227 DOI: 10.1038/s41598-017-09973-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 08/02/2017] [Indexed: 01/14/2023] Open
Abstract
Climate change models point to a decrease in water availability in semiarid areas that would compromise the maintenance of sustainable agriculture. Here, we used a grapefruit agroecosystem model to evaluate the responses of the active soil microbial community – as a microbial subset directly involved in soil functionality- undergoing strategies to cope with the low water availability in south-east Spain. For this purpose, we tested the impacts of: (i) water quality: transfer-water from a river (TW) or reclaimed-water from a wastewater-treatment plant (RW); and (ii) water quantity: continuous optimal amount of water or reduced irrigation (RDI) in the temporal frame when the crop is less sensitive; and their interactions. Metaproteomics revealed that the phylogenetic diversity of the active community and its functional diversity were lowered in soils with RW. RDI lowered soil respiration and functional diversity while the phylogenetic diversity remained constant. The reestablishment of full irrigation after RDI led to a recovery of soil respiration that was accompanied by an enhanced abundance of resilient bacterial populations. Bacterial populations displayed molecular mechanisms against water stress that have been conserved evolutionarily in plants. Protein-based studies shed light on ecological and functional mechanisms that govern the adaptive responses of soil microbial communities to climate-change friendly water management.
Collapse
Affiliation(s)
- Robert Starke
- Helmholtz-Centre for Environmental Research - UFZ, Department of Molecular Systems Biology, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Felipe Bastida
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain.
| | - Joaquín Abadía
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain
| | - Carlos García
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain
| | - Emilio Nicolás
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain
| | - Nico Jehmlich
- Helmholtz-Centre for Environmental Research - UFZ, Department of Molecular Systems Biology, Permoserstrasse 15, 04318, Leipzig, Germany
| |
Collapse
|
104
|
Gavazov K, Ingrisch J, Hasibeder R, Mills RTE, Buttler A, Gleixner G, Pumpanen J, Bahn M. Winter ecology of a subalpine grassland: Effects of snow removal on soil respiration, microbial structure and function. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 590-591:316-324. [PMID: 28279534 DOI: 10.1016/j.scitotenv.2017.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/08/2017] [Accepted: 03/02/2017] [Indexed: 06/06/2023]
Abstract
Seasonal snow cover provides essential insulation for mountain ecosystems, but expected changes in precipitation patterns and snow cover duration due to global warming can influence the activity of soil microbial communities. In turn, these changes have the potential to create new dynamics of soil organic matter cycling. To assess the effects of experimental snow removal and advanced spring conditions on soil carbon (C) and nitrogen (N) dynamics, and on the biomass and structure of soil microbial communities, we performed an in situ study in a subalpine grassland in the Austrian Alps, in conjunction with soil incubations under controlled conditions. We found substantial winter C-mineralisation and high accumulation of inorganic and organic N in the topsoil, peaking at snowmelt. Soil microbial biomass doubled under the snow, paralleled by a fivefold increase in its C:N ratio, but no apparent change in its bacteria-dominated community structure. Snow removal led to a series of mild freeze-thaw cycles, which had minor effects on in situ soil CO2 production and N mineralisation. Incubated soil under advanced spring conditions, however, revealed an impaired microbial metabolism shortly after snow removal, characterised by a limited capacity for C-mineralisation of both fresh plant-derived substrates and existing soil organic matter (SOM), leading to reduced priming effects. This effect was transient and the observed recovery in microbial respiration and SOM priming towards the end of the winter season indicated microbial resilience to short-lived freeze-thaw disturbance under field conditions. Bacteria showed a higher potential for uptake of plant-derived C substrates during this recovery phase. The observed temporary loss in microbial C-mineralisation capacity and the promotion of bacteria over fungi can likely impede winter SOM cycling in mountain grasslands under recurrent winter climate change events, with plausible implications for soil nutrient availability and plant-soil interactions.
Collapse
Affiliation(s)
- Konstantin Gavazov
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, 98107 Abisko, Sweden.
| | - Johannes Ingrisch
- Institute of Ecology, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - Roland Hasibeder
- Institute of Ecology, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - Robert T E Mills
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Alexandre Buttler
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015 Lausanne, Switzerland; Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Site Lausanne, Station 2, 1015 Lausanne, Switzerland; Laboratoire de Chrono-Environnement, UMR CNRS 6249, UFR des Sciences et Techniques, 16 route de Gray, Université de Franche-Comté, 25030 Besançon, France
| | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry, P.O. Box 100164, 07701 Jena, Germany
| | - Jukka Pumpanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
| | - Michael Bahn
- Institute of Ecology, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| |
Collapse
|
105
|
The Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability. FORESTS 2017. [DOI: 10.3390/f8070241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
106
|
Ishaq SL. Plant-microbial interactions in agriculture and the use of farming systems to improve diversity and productivity. AIMS Microbiol 2017; 3:335-353. [PMID: 31294165 PMCID: PMC6605018 DOI: 10.3934/microbiol.2017.2.335] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/04/2017] [Indexed: 11/18/2022] Open
Abstract
A thorough understanding of the services provided by microorganisms to the agricultural ecosystem is integral to understanding how management systems can improve or deteriorate soil health and production over the long term. Yet it is hampered by the difficulty in measuring the intersection of plant, microbe, and environment, in no small part because of the situational specificity to some plant-microbial interactions, related to soil moisture, nutrient content, climate, and local diversity. Despite this, perspective on soil microbiota in agricultural settings can inform management practices to improve the sustainability of agricultural production.
Collapse
Affiliation(s)
- Suzanne L Ishaq
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, Montana, USA
| |
Collapse
|
107
|
Karst J, Gaster J, Wiley E, Landhäusser SM. Stress differentially causes roots of tree seedlings to exude carbon. TREE PHYSIOLOGY 2017; 37:154-164. [PMID: 27744381 DOI: 10.1093/treephys/tpw090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/04/2016] [Indexed: 05/29/2023]
Abstract
How carbon (C) flows through plants into soils is poorly understood. Carbon exuded comes from a pool of non-structural carbohydrates (NSC) in roots. Simple models of diffusion across concentration gradients indicate that the more C in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by plants. Thus, stress type may influence exudation independent of NSC. We tested this hypothesis by examining the relationship between NSC in fine roots and exudation of organic C in aspen (Populus tremuloides Michx.) seedlings after exposure to shade, cold soils and drought in a controlled environment. Fine root concentrations of NSC varied by treatment. Mass-specific C exudation increased with increasing fine root sugar concentration in all treatments, but stress type affected exudation independently of sugar concentration. Seedlings exposed to cold soils exuded the most C on a per mass basis. Through 13C labeling, we also found that stressed seedlings allocated relatively more new C to exudates than roots compared with unstressed seedlings. Stress affects exudation of C via mechanisms other than changes in root carbohydrate availability.
Collapse
Affiliation(s)
- Justine Karst
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Jacob Gaster
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Erin Wiley
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Simon M Landhäusser
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| |
Collapse
|
108
|
Sayer EJ, Oliver AE, Fridley JD, Askew AP, Mills RTE, Grime JP. Links between soil microbial communities and plant traits in a species-rich grassland under long-term climate change. Ecol Evol 2017; 7:855-862. [PMID: 28168022 PMCID: PMC5288249 DOI: 10.1002/ece3.2700] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/30/2016] [Accepted: 11/27/2016] [Indexed: 11/09/2022] Open
Abstract
Climate change can influence soil microorganisms directly by altering their growth and activity but also indirectly via effects on the vegetation, which modifies the availability of resources. Direct impacts of climate change on soil microorganisms can occur rapidly, whereas indirect effects mediated by shifts in plant community composition are not immediately apparent and likely to increase over time. We used molecular fingerprinting of bacterial and fungal communities in the soil to investigate the effects of 17 years of temperature and rainfall manipulations in a species‐rich grassland near Buxton, UK. We compared shifts in microbial community structure to changes in plant species composition and key plant traits across 78 microsites within plots subjected to winter heating, rainfall supplementation, or summer drought. We observed marked shifts in soil fungal and bacterial community structure in response to chronic summer drought. Importantly, although dominant microbial taxa were largely unaffected by drought, there were substantial changes in the abundances of subordinate fungal and bacterial taxa. In contrast to short‐term studies that report high resistance of soil fungi to drought, we observed substantial losses of fungal taxa in the summer drought treatments. There was moderate concordance between soil microbial communities and plant species composition within microsites. Vector fitting of community‐weighted mean plant traits to ordinations of soil bacterial and fungal communities showed that shifts in soil microbial community structure were related to plant traits representing the quality of resources available to soil microorganisms: the construction cost of leaf material, foliar carbon‐to‐nitrogen ratios, and leaf dry matter content. Thus, our study provides evidence that climate change could affect soil microbial communities indirectly via changes in plant inputs and highlights the importance of considering long‐term climate change effects, especially in nutrient‐poor systems with slow‐growing vegetation.
Collapse
Affiliation(s)
- Emma J Sayer
- Lancaster Environment Centre Lancaster University Lancaster UK; Smithsonian Tropical Research Institute Panama Republic of Panama; Department of Environment, Earth and Ecosystems The Open University Milton Keynes UK
| | | | | | - Andrew P Askew
- Department of Biology Syracuse University Syracuse NY USA
| | | | - J Philip Grime
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| |
Collapse
|
109
|
Naylor D, Coleman-Derr D. Drought Stress and Root-Associated Bacterial Communities. FRONTIERS IN PLANT SCIENCE 2017; 8:2223. [PMID: 29375600 PMCID: PMC5767233 DOI: 10.3389/fpls.2017.02223] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/18/2017] [Indexed: 05/20/2023]
Abstract
Root-associated bacterial communities play a vital role in maintaining health of the plant host. These communities exist in complex relationships, where composition and abundance of community members is dependent on a number of factors such as local soil chemistry, plant genotype and phenotype, and perturbations in the surrounding abiotic environment. One common perturbation, drought, has been shown to have drastic effects on bacterial communities, yet little is understood about the underlying causes behind observed shifts in microbial abundance. As drought may affect root bacterial communities both directly by modulating moisture availability, as well as indirectly by altering soil chemistry and plant phenotypes, we provide a synthesis of observed trends in recent studies and discuss possible directions for future research that we hope will provide for more knowledgeable predictions about community responses to future drought events.
Collapse
Affiliation(s)
- Dan Naylor
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, Albany, CA, United States
| | - Devin Coleman-Derr
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, Albany, CA, United States
- *Correspondence: Devin Coleman-Derr,
| |
Collapse
|
110
|
von Rein I, Kayler ZE, Premke K, Gessler A. Desiccation of sediments affects assimilate transport within aquatic plants and carbon transfer to microorganisms. PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18:947-961. [PMID: 27465780 DOI: 10.1111/plb.12486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 07/21/2016] [Indexed: 06/06/2023]
Abstract
With the projected increase in drought duration and intensity in future, small water bodies, and especially the terrestrial-aquatic interfaces, will be subjected to longer dry periods with desiccation of the sediment. Drought effects on the plant-sediment microorganism carbon continuum may disrupt the tight linkage between plants and microbes which governs sediment carbon and nutrient cycling, thus having a potential negative impact on carbon sequestration of small freshwater ecosystems. However, research on drought effects on the plant-sediment carbon transfer in aquatic ecosystems is scarce. We therefore exposed two emergent aquatic macrophytes, Phragmites australis and Typha latifolia, to a month-long summer drought in a mesocosm experiment. We followed the fate of carbon from leaves to sediment microbial communities with 13 CO2 pulse labelling and microbial phospholipid-derived fatty acid (PLFA) analysis. We found that drought reduced the total amount of carbon allocated to stem tissues but did not delay the transport. We also observed an increase in accumulation of 13 C-labelled sugars in roots and found a reduced incorporation of 13 C into the PLFAs of sediment microorganisms. Drought induced a switch in plant carbon allocation priorities, where stems received less new assimilates leading to reduced starch reserves whilst roots were prioritised with new assimilates, suggesting their use for osmoregulation. There were indications that the reduced carbon transfer from roots to microorganisms was due to the reduction of microbial activity via direct drought effects rather than to a decrease in root exudation or exudate availability.
Collapse
Affiliation(s)
- I von Rein
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany.
| | - Z E Kayler
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
- USDA Forest Service, Northern Research Station, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - K Premke
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
- Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - A Gessler
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| |
Collapse
|
111
|
Drought and Carbon Cycling of Grassland Ecosystems under Global Change: A Review. WATER 2016. [DOI: 10.3390/w8100460] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
112
|
Fuchslueger L, Bahn M, Hasibeder R, Kienzl S, Fritz K, Schmitt M, Watzka M, Richter A. Drought history affects grassland plant and microbial carbon turnover during and after a subsequent drought event. THE JOURNAL OF ECOLOGY 2016. [PMID: 27609992 DOI: 10.5061/dryad.2t3sn] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Drought periods are projected to become more severe and more frequent in many European regions. While effects of single strong droughts on plant and microbial carbon (C) dynamics have been studied in some detail, impacts of recurrent drought events are still little understood.We tested whether the legacy of extreme experimental drought affects responses of plant and microbial C and nitrogen (N) turnover to further drought and rewetting. In a mountain grassland, we conducted a 13C pulse-chase experiment during a naturally occurring drought and rewetting event in plots previously exposed to experimental droughts and in ambient controls (AC). After labelling, we traced 13C below-ground allocation and incorporation into soil microbes using phospholipid fatty acid biomarkers.Drought history (DH) had no effects on the standing shoot and fine root plant biomass. However, plants with experimental DH displayed decreased shoot N concentrations and increased fine root N concentrations relative to those in AC. During the natural drought, plants with DH assimilated and allocated less 13C below-ground; moreover, fine root respiration was reduced and not fuelled by fresh C compared to plants in AC.Regardless of DH, microbial biomass remained stable during natural drought and rewetting. Although microbial communities initially differed in their composition between soils with and without DH, they responded to the natural drought and rewetting in a similar way: gram-positive bacteria increased, while fungal and gram-negative bacteria remained stable. In soils with DH, a strongly reduced uptake of recent plant-derived 13C in microbial biomarkers was observed during the natural drought, pointing to a smaller fraction of active microbes or to a microbial community that is less dependent on plant C. Synthesis. Drought history can induce changes in above- vs. below-ground plant N concentrations and affect the response of plant C turnover to further droughts and rewetting by decreasing plant C uptake and below-ground allocation. DH does not affect the responses of the microbial community to further droughts and rewetting, but alters microbial functioning, particularly the turnover of recent plant-derived carbon, during and after further drought periods.
Collapse
Affiliation(s)
- Lucia Fuchslueger
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14A-1090 Vienna Austria; Present address: National Institute for Amazonian Research (INPA) Av. André Araujo 2936 Aleixo Manaus Amazonas CEP: 69067-375 Brazil
| | - Michael Bahn
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Roland Hasibeder
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Sandra Kienzl
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14 A-1090 Vienna Austria
| | - Karina Fritz
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Michael Schmitt
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Margarete Watzka
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14 A-1090 Vienna Austria
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14 A-1090 Vienna Austria
| |
Collapse
|
113
|
Fuchslueger L, Bahn M, Hasibeder R, Kienzl S, Fritz K, Schmitt M, Watzka M, Richter A. Drought history affects grassland plant and microbial carbon turnover during and after a subsequent drought event. THE JOURNAL OF ECOLOGY 2016; 104:1453-1465. [PMID: 27609992 PMCID: PMC4996329 DOI: 10.1111/1365-2745.12593] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 04/18/2016] [Indexed: 05/07/2023]
Abstract
Drought periods are projected to become more severe and more frequent in many European regions. While effects of single strong droughts on plant and microbial carbon (C) dynamics have been studied in some detail, impacts of recurrent drought events are still little understood.We tested whether the legacy of extreme experimental drought affects responses of plant and microbial C and nitrogen (N) turnover to further drought and rewetting. In a mountain grassland, we conducted a 13C pulse-chase experiment during a naturally occurring drought and rewetting event in plots previously exposed to experimental droughts and in ambient controls (AC). After labelling, we traced 13C below-ground allocation and incorporation into soil microbes using phospholipid fatty acid biomarkers.Drought history (DH) had no effects on the standing shoot and fine root plant biomass. However, plants with experimental DH displayed decreased shoot N concentrations and increased fine root N concentrations relative to those in AC. During the natural drought, plants with DH assimilated and allocated less 13C below-ground; moreover, fine root respiration was reduced and not fuelled by fresh C compared to plants in AC.Regardless of DH, microbial biomass remained stable during natural drought and rewetting. Although microbial communities initially differed in their composition between soils with and without DH, they responded to the natural drought and rewetting in a similar way: gram-positive bacteria increased, while fungal and gram-negative bacteria remained stable. In soils with DH, a strongly reduced uptake of recent plant-derived 13C in microbial biomarkers was observed during the natural drought, pointing to a smaller fraction of active microbes or to a microbial community that is less dependent on plant C. Synthesis. Drought history can induce changes in above- vs. below-ground plant N concentrations and affect the response of plant C turnover to further droughts and rewetting by decreasing plant C uptake and below-ground allocation. DH does not affect the responses of the microbial community to further droughts and rewetting, but alters microbial functioning, particularly the turnover of recent plant-derived carbon, during and after further drought periods.
Collapse
Affiliation(s)
- Lucia Fuchslueger
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14A-1090 Vienna Austria; Present address: National Institute for Amazonian Research (INPA) Av. André Araujo 2936 Aleixo Manaus Amazonas CEP: 69067-375 Brazil
| | - Michael Bahn
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Roland Hasibeder
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Sandra Kienzl
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14 A-1090 Vienna Austria
| | - Karina Fritz
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Michael Schmitt
- Institute of Ecology University of Innsbruck Sternwartestrasse 15 A-6020 Innsbruck Austria
| | - Margarete Watzka
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14 A-1090 Vienna Austria
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science University of Vienna Althanstrasse 14 A-1090 Vienna Austria
| |
Collapse
|
114
|
von Rein I, Gessler A, Premke K, Keitel C, Ulrich A, Kayler ZE. Forest understory plant and soil microbial response to an experimentally induced drought and heat-pulse event: the importance of maintaining the continuum. GLOBAL CHANGE BIOLOGY 2016; 22:2861-74. [PMID: 26946456 DOI: 10.1111/gcb.13270] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 01/15/2016] [Accepted: 02/22/2016] [Indexed: 05/21/2023]
Abstract
Drought duration and intensity are expected to increase with global climate change. How changes in water availability and temperature affect the combined plant-soil-microorganism response remains uncertain. We excavated soil monoliths from a beech (Fagus sylvatica L.) forest, thus keeping the understory plant-microbe communities intact, imposed an extreme climate event, consisting of drought and/or a single heat-pulse event, and followed microbial community dynamics over a time period of 28 days. During the treatment, we labeled the canopy with (13) CO2 with the goal of (i) determining the strength of plant-microbe carbon linkages under control, drought, heat and heat-drought treatments and (ii) characterizing microbial groups that are tightly linked to the plant-soil carbon continuum based on (13) C-labeled PLFAs. Additionally, we used 16S rRNA sequencing of bacteria from the Ah horizon to determine the short-term changes in the active microbial community. The treatments did not sever within-plant transport over the experiment, and carbon sinks belowground were still active. Based on the relative distribution of labeled carbon to roots and microbial PLFAs, we determined that soil microbes appear to have a stronger carbon sink strength during environmental stress. High-throughput sequencing of the 16S rRNA revealed multiple trajectories in microbial community shifts within the different treatments. Heat in combination with drought had a clear negative effect on microbial diversity and resulted in a distinct shift in the microbial community structure that also corresponded to the lowest level of label found in the PLFAs. Hence, the strongest changes in microbial abundances occurred in the heat-drought treatment where plants were most severely affected. Our study suggests that many of the shifts in the microbial communities that we might expect from extreme environmental stress will result from the plant-soil-microbial dynamics rather than from direct effects of drought and heat on soil microbes alone.
Collapse
Affiliation(s)
- Isabell von Rein
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
| | - Arthur Gessler
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Altensteinstr 6, D-14195 Berlin, Germany
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstr 111, CH-8903, Birmensdorf, Switzerland
| | - Katrin Premke
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Chemical Analytics and Biogeochemistry, Müggelseedamm 310, 12587 Berlin, Germany
| | - Claudia Keitel
- Centre for Carbon, Water and Food, Faculty of Agriculture & Environment, university of sydney, 380 Werombi Rd, Brownlow Hill, NSW 2570, Australia
| | - Andreas Ulrich
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
| | - Zachary E Kayler
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
| |
Collapse
|
115
|
Zeng Q, Dong Y, An S. Bacterial Community Responses to Soils along a Latitudinal and Vegetation Gradient on the Loess Plateau, China. PLoS One 2016; 11:e0152894. [PMID: 27045518 PMCID: PMC4821562 DOI: 10.1371/journal.pone.0152894] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/21/2016] [Indexed: 11/19/2022] Open
Abstract
Soil bacterial communities play an important role in nutrient recycling and storage in terrestrial ecosystems. Loess soils are one of the most important soil resources for maintaining the stability of vegetation ecosystems and are mainly distributed in northwest China. Estimating the distributions and affecting factors of soil bacterial communities associated with various types of vegetation will inform our understanding of the effect of vegetation restoration and climate change on these processes. In this study, we collected soil samples from 15 sites from north to south on the Loess Plateau of China that represent different ecosystem types and analyzed the distributions of soil bacterial communities by high-throughput 454 pyrosequencing. The results showed that the 142444 sequences were grouped into 36816 operational taxonomic units (OTUs) based on 97% similarity. The results of the analysis showed that the dominant taxonomic phyla observed in all samples were Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria and Planctomycetes. Actinobacteria and Proteobacteria were the two most abundant groups in all samples. The relative abundance of Actinobacteria increased from 14.73% to 40.22% as the ecosystem changed from forest to sandy, while the relative abundance of Proteobacteria decreased from 35.35% to 21.40%. Actinobacteria and Proteobacteria had significant correlations with mean annual precipitation (MAP), pH, and soil moisture and nutrients. MAP was significantly correlated with soil chemical and physical properties. The relative abundance of Actinobacteria, Proteobacteria and Planctomycetes correlated significantly with MAP, suggesting that MAP was a key factor that affected the soil bacterial community composition. However, along with the MAP gradient, Chloroflexi, Bacteroidetes and Cyanobacteria had narrow ranges that did not significantly vary with the soil and environmental factors. Overall, we conclude that the edaphic properties and/or vegetation types are driving bacterial community composition. MAP was a key factor that affects the composition of the soil bacteria on the Loess Plateau of China.
Collapse
Affiliation(s)
- Quanchao Zeng
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Yanghong Dong
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Shaoshan An
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, P.R. China
- State Key Laboratory of Soil Erosion and Dry Land Farming on Loess Plateau, Northwest A&F University, Yangling, Shaanxi, P.R. China
- * E-mail:
| |
Collapse
|
116
|
Orwin KH, Dickie IA, Wood JR, Bonner KI, Holdaway RJ. Soil microbial community structure explains the resistance of respiration to a dry–rewet cycle, but not soil functioning under static conditions. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12610] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kate H. Orwin
- Delaware Cres Christchurch 8042 New Zealand
- Landcare Research PO Box 69040 Lincoln 7640 New Zealand
| | - Ian A. Dickie
- Landcare Research PO Box 69040 Lincoln 7640 New Zealand
- Bio‐Protection Research Centre Lincoln University PO Box 85084 Lincoln 7647 New Zealand
| | - Jamie R. Wood
- Landcare Research PO Box 69040 Lincoln 7640 New Zealand
| | | | | |
Collapse
|
117
|
Wegener F, Beyschlag W, Werner C. High intraspecific ability to adjust both carbon uptake and allocation under light and nutrient reduction in Halimium halimifolium L. FRONTIERS IN PLANT SCIENCE 2015; 6:609. [PMID: 26300906 PMCID: PMC4528176 DOI: 10.3389/fpls.2015.00609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/23/2015] [Indexed: 05/28/2023]
Abstract
The allocation of recently assimilated carbon (C) by plants depends on developmental stage and on environmental factors, but the underlying mechanisms are still a matter of debate. In the present study, we investigated the regulation of C uptake and allocation and their adjustments during plant growth. We induced different allocation strategies in the Mediterranean shrub Halimium halimifolium L. by a reduction of light (Low L treatment) and nutrient availability (Low N treatment) and analyzed allocation parameters as well as morphological and physiological traits for 15 months. Further, we conducted a (13)CO2 pulse-labeling and followed the way of recently assimilated carbon to eight different tissue classes and respiration for 13 days. The plant responses were remarkably distinct in our study, with mainly morphological/physiological adaptions in case of light reduction and adjustment of C allocation in case of nutrient reduction. The transport of recently assimilated C to the root system was enhanced in amount (c. 200%) and velocity under nutrient limited conditions compared to control plants. Despite the 57% light reduction the total biomass production was not affected in the Low L treatment. The plants probably compensated light reduction by an improvement of their ability to fix C. Thus, our results support the concept that photosynthesis is, at least in a medium term perspective, influenced by the C demand of the plant and not exclusively by environmental factors. Finally, our results indicate that growing heterotrophic tissues strongly reduce the C reflux from storage and structural C pools and therefore enhance the fraction of recent assimilates allocated to respiration. We propose that this interruption of the C reflux from storage and structural C pools could be a regulation mechanism for C translocation in plants.
Collapse
Affiliation(s)
- Frederik Wegener
- Ecosystem Physiology, University of FreiburgFreiburg, Germany
- AgroEcosystem Research, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of BayreuthBayreuth, Germany
| | - Wolfram Beyschlag
- Experimental and Systems Ecology, University of BielefeldBielefeld, Germany
| | - Christiane Werner
- Ecosystem Physiology, University of FreiburgFreiburg, Germany
- AgroEcosystem Research, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of BayreuthBayreuth, Germany
| |
Collapse
|
118
|
Frank D, Reichstein M, Bahn M, Thonicke K, Frank D, Mahecha MD, Smith P, van der Velde M, Vicca S, Babst F, Beer C, Buchmann N, Canadell JG, Ciais P, Cramer W, Ibrom A, Miglietta F, Poulter B, Rammig A, Seneviratne SI, Walz A, Wattenbach M, Zavala MA, Zscheischler J. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts. GLOBAL CHANGE BIOLOGY 2015; 21:2861-80. [PMID: 25752680 PMCID: PMC4676934 DOI: 10.1111/gcb.12916] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/24/2015] [Indexed: 05/19/2023]
Abstract
Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global upscaling of the impacts of climate extremes on global carbon-climate feedbacks.
Collapse
Affiliation(s)
- Dorothea Frank
- Max Planck Institute for Biogeochemistry07745, Jena, Germany
- Correspondence: Dorothea Frank, tel. + 49 3641 576284, fax + 49 3641 577200, e-mail:
| | | | - Michael Bahn
- Institute of Ecology, University of Innsbruck6020, Innsbruck, Austria
| | - Kirsten Thonicke
- Potsdam Institute for Climate Impact Research (PIK) e.V.14773, Potsdam, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB)14195, Berlin, Germany
| | - David Frank
- Swiss Federal Research Institute WSL8903, Birmensdorf, Switzerland
- Oeschger Centre for Climate Change Research, University of BernCH-3012, Bern, Switzerland
| | | | - Pete Smith
- Institute of Biological and Environmental Sciences, University of Aberdeen23 St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Marijn van der Velde
- Ecosystems Services and Management Program, International Institute of Applied Systems Analysis (IIASA)A-2361, Laxenburg, Austria
| | - Sara Vicca
- Research Group of Plant and Vegetation Ecology, Biology Department, University of AntwerpWilrijk, Belgium
| | - Flurin Babst
- Potsdam Institute for Climate Impact Research (PIK) e.V.14773, Potsdam, Germany
- Laboratory of Tree-Ring Research, The University of Arizona1215 E Lowell St, Tucson, AZ, 85721, USA
| | - Christian Beer
- Max Planck Institute for Biogeochemistry07745, Jena, Germany
- Department of Environmental Science and Analytical Chemistry (ACES), Bolin Centre for Climate Research, Stockholm University10691, Stockholm, Sweden
| | | | - Josep G Canadell
- Global Carbon Project, CSIRO Oceans and Atmosphere FlagshipGPO Box 3023, Canberra, ACT, 2601, Australia
| | - Philippe Ciais
- IPSL – Laboratoire des Sciences du Climat et de l’Environnement CEA-CNRS-UVSQ91191, Gif sur Yvette, France
| | - Wolfgang Cramer
- Institut Méditerranéen de Biodiversité et d’Ecologie marine et continentale (IMBE), Aix Marseille Université, CNRS, IRD, Avignon UniversitéAix-en-Provence, France
| | - Andreas Ibrom
- Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU)Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Franco Miglietta
- IBIMET-CNRVia Caproni, 8, 50145, Firenze, Italy
- FoxLab, Fondazione E.MachVia Mach 1, 30158, San Michele a/Adige, Trento, Italy
| | - Ben Poulter
- IPSL – Laboratoire des Sciences du Climat et de l’Environnement CEA-CNRS-UVSQ91191, Gif sur Yvette, France
| | - Anja Rammig
- Oeschger Centre for Climate Change Research, University of BernCH-3012, Bern, Switzerland
- Institute of Biological and Environmental Sciences, University of Aberdeen23 St Machar Drive, Aberdeen, AB24 3UU, UK
| | | | - Ariane Walz
- Institute of Earth and Environmental Science, University of Potsdam14476, Potsdam, Germany
| | - Martin Wattenbach
- Helmholtz Centre Potsdam, GFZ German Research Centre For Geosciences14473, Potsdam, Germany
| | - Miguel A Zavala
- Forest Ecology and Restoration Group, Universidad de AlcaláAlcalá de Henares, Madrid, Spain
| | | |
Collapse
|
119
|
Flores-Rentería D, Curiel Yuste J, Rincón A, Brearley FQ, García-Gil JC, Valladares F. Habitat Fragmentation can Modulate Drought Effects on the Plant-soil-microbial System in Mediterranean Holm Oak (Quercus ilex) Forests. MICROBIAL ECOLOGY 2015; 69:798-812. [PMID: 25724140 DOI: 10.1007/s00248-015-0584-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 02/13/2015] [Indexed: 06/04/2023]
Abstract
Ecological transformations derived from habitat fragmentation have led to increased threats to above-ground biodiversity. However, the impacts of forest fragmentation on soils and their microbial communities are not well understood. We examined the effects of contrasting fragment sizes on the structure and functioning of soil microbial communities from holm oak forest patches in two bioclimatically different regions of Spain. We used a microcosm approach to simulate the annual summer drought cycle and first autumn rainfall (rewetting), evaluating the functional response of a plant-soil-microbial system. Forest fragment size had a significant effect on physicochemical characteristics and microbial functioning of soils, although the diversity and structure of microbial communities were not affected. The response of our plant-soil-microbial systems to drought was strongly modulated by the bioclimatic conditions and the fragment size from where the soils were obtained. Decreasing fragment size modulated the effects of drought by improving local environmental conditions with higher water and nutrient availability. However, this modulation was stronger for plant-soil-microbial systems built with soils from the northern region (colder and wetter) than for those built with soils from the southern region (warmer and drier) suggesting that the responsiveness of the soil-plant-microbial system to habitat fragmentation was strongly dependent on both the physicochemical characteristics of soils and the historical adaptation of soil microbial communities to specific bioclimatic conditions. This interaction challenges our understanding of future global change scenarios in Mediterranean ecosystems involving drier conditions and increased frequency of forest fragmentation.
Collapse
Affiliation(s)
- Dulce Flores-Rentería
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN), Spanish Scientific Council (CSIC), Serrano 115bis, 28006, Madrid, Spain,
| | | | | | | | | | | |
Collapse
|
120
|
Soil bacterial community structure responses to precipitation reduction and forest management in forest ecosystems across Germany. PLoS One 2015; 10:e0122539. [PMID: 25875835 PMCID: PMC4397059 DOI: 10.1371/journal.pone.0122539] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/16/2015] [Indexed: 01/01/2023] Open
Abstract
Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season.
Collapse
|
121
|
Hasibeder R, Fuchslueger L, Richter A, Bahn M. Summer drought alters carbon allocation to roots and root respiration in mountain grassland. THE NEW PHYTOLOGIST 2015; 205:1117-1127. [PMID: 25385284 PMCID: PMC4303983 DOI: 10.1111/nph.13146] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/21/2014] [Indexed: 05/04/2023]
Abstract
Drought affects the carbon (C) source and sink activities of plant organs, with potential consequences for belowground C allocation, a key process of the terrestrial C cycle. The responses of belowground C allocation dynamics to drought are so far poorly understood. We combined experimental rain exclusion with (13)C pulse labelling in a mountain meadow to analyse the effects of summer drought on the dynamics of belowground allocation of recently assimilated C and how it is partitioned among different carbohydrate pools and root respiration. Severe soil moisture deficit decreased the ecosystem C uptake and the amounts and velocity of C allocated from shoots to roots. However, the proportion of recently assimilated C translocated belowground remained unaffected by drought. Reduced root respiration, reflecting reduced C demand under drought, was increasingly sustained by C reserves, whilst recent assimilates were preferentially allocated to root storage and an enlarged pool of osmotically active compounds. Our results indicate that under drought conditions the usage of recent photosynthates is shifted from metabolic activity to osmotic adjustment and storage compounds.
Collapse
Affiliation(s)
- Roland Hasibeder
- Institute of Ecology, University of InnsbruckSternwartestraße 15, 6020, Innsbruck, Austria
| | - Lucia Fuchslueger
- Division of Terrestrial Ecosystem Research, Department of Chemical Ecology and Ecosystem Research, University of ViennaAlthanstraße 14, 1090, Vienna, Austria
| | - Andreas Richter
- Division of Terrestrial Ecosystem Research, Department of Chemical Ecology and Ecosystem Research, University of ViennaAlthanstraße 14, 1090, Vienna, Austria
| | - Michael Bahn
- Institute of Ecology, University of InnsbruckSternwartestraße 15, 6020, Innsbruck, Austria
| |
Collapse
|
122
|
Curiel Yuste J, Fernandez-Gonzalez AJ, Fernandez-Lopez M, Ogaya R, Penuelas J, Lloret F. Functional diversification within bacterial lineages promotes wide functional overlapping between taxonomic groups in a Mediterranean forest soil. FEMS Microbiol Ecol 2014; 90:54-67. [DOI: 10.1111/1574-6941.12373] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 11/28/2022] Open
Affiliation(s)
| | | | | | - Romá Ogaya
- CREAF; Cerdanyola del Vallès (Barcelona) Spain
- Global Ecology Unit CREAF-CEAB-CSIC-UAB; CSIC; Cerdanyola del Vallès (Barcelona) Spain
| | - Josep Penuelas
- CREAF; Cerdanyola del Vallès (Barcelona) Spain
- Global Ecology Unit CREAF-CEAB-CSIC-UAB; CSIC; Cerdanyola del Vallès (Barcelona) Spain
| | | |
Collapse
|