1
|
Voigt C, Dubbert M, Launiainen S, Porada P, Oestmann J, Piayda A. Impact of vegetation composition and seasonality on sensitivity of modelled CO 2 exchange in temperate raised bogs. Sci Rep 2024; 14:11023. [PMID: 38744922 PMCID: PMC11094101 DOI: 10.1038/s41598-024-61229-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
Encroachment of vascular plants (VP) in temperate raised bogs, as a consequence of altered hydrological conditions and nutrient input, is widely observed. Effects of such vegetation shift on water and carbon cycles are, however, largely unknown and identification of responsible plant physiological traits is challenging. Process-based modelling offers the opportunity of gaining insights into ecosystem functioning beyond observations, and to infer decisive trait shifts of plant functional groups. We adapted the Soil-Vegetation-Atmosphere Transfer model pyAPES to a temperate raised bog site by calibration against measured peat temperature, water table and surface CO2 fluxes. We identified the most important traits determining CO2 fluxes by conducting Morris sensitivity analysis (MSA) under changing conditions throughout the year and simulated VP encroachment. We further investigated transferability of results to other sites by extending MSA to parameter ranges derived from literature review. We found highly variable intra-annual plant traits importance determining ecosystem CO2 fluxes, but only a partial shift of importance of photosynthetic processes from moss to VP during encroachment. Ecosystem respiration was dominated by peat respiration. Overall, carboxylation rate, base respiration rate and temperature sensitivity (Q10) were most important for determining bog CO2 balance and parameter ranking was robust even under the extended MSA.
Collapse
Affiliation(s)
- Claas Voigt
- Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straße 84, 15374, Müncheberg, Germany.
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65A, 38116, Braunschweig, Germany.
| | - Maren Dubbert
- Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straße 84, 15374, Müncheberg, Germany
| | - Samuli Launiainen
- Natural Resources Institute Finland (LUKE), Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Philipp Porada
- Institute of Plant Science and Microbiology, Universität Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany
| | - Jan Oestmann
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65A, 38116, Braunschweig, Germany
| | - Arndt Piayda
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65A, 38116, Braunschweig, Germany
| |
Collapse
|
2
|
Yang Q, Liu Z, Bai E. Comparison of carbon and nitrogen accumulation rate between bog and fen phases in a pristine peatland with the fen-bog transition. GLOBAL CHANGE BIOLOGY 2023; 29:6350-6366. [PMID: 37602716 DOI: 10.1111/gcb.16915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Long-term carbon and nitrogen dynamics in peatlands are affected by both vegetation production and decomposition processes. Here, we examined the carbon accumulation rate (CAR), nitrogen accumulation rate (NAR) and δ13 C, δ15 N of plant residuals in a peat core dated back to ~8500 cal year BP in a temperate peatland in Northeast China. Impacted by the tephra during 1160 and 789 cal year BP and climate change, the peatland changed from a fen dominated by vascular plants to a bog dominated by Sphagnum mosses. We used the Clymo model to quantify peat addition rate and decay constant for acrotelm and catotelm layers during both bog and fen phases. Our studied peatland was dominated by Sphagnum fuscum during the bog phase (789 to -59 cal year BP) and lower accumulation rates in the acrotelm layer was found during this phase, suggesting the dominant role of volcanic eruption in the CAR of the peat core. Both mean CAR and NAR were higher during the bog phase than during the fen phase in our study, consistent with the results of the only one similar study in the literature. Because the input rate of organic matter was considered to be lower during the bog phase, the decomposition process must have been much lower during the bog phase than during the fen phase and potentially controlled CAR and NAR. During the fen phase, CAR was also lower under higher temperature and summer insolation, conditions beneficial for decomposition. δ15 N of Sphagnum hinted that nitrogen fixation had a positive effect on nitrogen accumulation, particular in recent decades. Our study suggested that decomposition is more important for carbon and nitrogen sequestration than production in peatlands in most conditions and if future climate changes or human disturbance increase decomposition rate, carbon sequestration in peatlands will be jeopardized.
Collapse
Affiliation(s)
- Qiannan Yang
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
| | - Ziping Liu
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, China
| | - Edith Bai
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, China
| |
Collapse
|
3
|
Che L, Zhang H, Wan L. Spatial distribution of permafrost degradation and its impact on vegetation phenology from 2000 to 2020. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162889. [PMID: 36933732 DOI: 10.1016/j.scitotenv.2023.162889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 03/10/2023] [Accepted: 03/12/2023] [Indexed: 05/06/2023]
Abstract
As global temperatures rise, permafrost is degraded. Permafrost degradation alters vegetation phenology and community composition, thereby affecting local and regional ecosystems. The Xing'an Mountains, located on the southern edge of the Eurasian permafrost region, are very sensitive to the impact of permafrost degradation on ecosystems. Climate change has direct effects on permafrost and vegetation growth, and analysis of the indirect effects of permafrost degradation on vegetation phenology based on the normalized difference vegetation index (NDVI) can explain the internal impact mechanisms of ecosystem components. Based on the temperature at the top of permafrost (TTOP) model, which was used to simulate the spatial distribution of permafrost areas in the Xing'an Mountains from 2000 to 2020, the areas of the three permafrost types showed a decreasing trend. The mean annual surface temperature (MAST) increased significantly at a rate of 0.008 °C year-1 from 2000 to 2020, and the southern boundary of the permafrost region moved north by 0.1-1 degrees. The average NDVI value of the permafrost region increased significantly in 8.34 % of the region. The significant correlations between NDVI and permafrost degradation, temperature and precipitation in the permafrost degradation region were 92.06 % (80.19 % positive, 11.87 % negative), 50.37 % (42.72 % positive, 7.65 % negative), and 81.59 % (36.25 % positive, 45.34 % negative), and were mainly distributed along the southern boundary of the permafrost region. A significance test of phenology in the Xing'an Mountains showed that the end of the growing season (EOS) and the length of the growing season (GLS) were significantly delayed and prolonged in the southern sparse island permafrost region. Sensitivity analysis showed that permafrost degradation was the main factor that affected the start of the growing season (SOS) and GLS. When the effects of temperature, precipitation, and sunshine duration were excluded, the regions with a significant positive correlation between permafrost degradation and SOS (20.96 %) and GLS (28.55 %) were located in both continuous and discontinuous permafrost regions. The regions with a significant negative correlation between permafrost degradation and SOS (21.11 %) and GLS (8.98 %) were mainly distributed on the southern edge of the island permafrost region. In summary, the NDVI changed significantly in the southern boundary of the permafrost region, and this change was mainly attributed to permafrost degradation.
Collapse
Affiliation(s)
- Lina Che
- Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin 150025, People's Republic of China
| | - Honghua Zhang
- Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin 150025, People's Republic of China
| | - Luhe Wan
- Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin 150025, People's Republic of China.
| |
Collapse
|
4
|
Newman JE, Levasseur PA, Beckett P, Watmough SA. The impact of severe pollution from smelter emissions on carbon and metal accumulation in peatlands in Ontario, Canada. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 320:121102. [PMID: 36669721 DOI: 10.1016/j.envpol.2023.121102] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 12/13/2022] [Accepted: 01/16/2023] [Indexed: 06/17/2023]
Abstract
Peatlands are unique habitats that function as a carbon (C) sink and an archive of atmospheric metal deposition. Sphagnum mosses are key components of peatlands but can be adversely impacted by air pollution potentially affecting rates of C and metal accumulation in peat. In this study we evaluate how the loss of Sphagnum in peatlands close to a copper (Cu) and nickel (Ni) smelter in Sudbury, Ontario affected C accumulation and metal profiles. The depth of accumulated peat formed during the 100+ year period of smelter activities also increased with distance from the smelter. Concurrently, peat bulk density decreased with distance from the smelter, which resulted in relatively similar average rates of apparent C accumulation (32-46 g/m2/yr). These rates are within the range of published values despite the historically high pollution loadings. Surface peat close to the smelters was greatly enriched in Cu and Ni, and Cu profiles in dated peat cores generally coincide with known pollution histories much better than Ni that increased well before the beginning of smelter activities likely a result of post-deposition mobility in peat cores.
Collapse
Affiliation(s)
- Jodi E Newman
- Environmental and Life Sciences, Trent University, Peterborough, ON, K9L 0G2, Canada.
| | - Patrick A Levasseur
- Environmental and Life Sciences, Trent University, Peterborough, ON, K9L 0G2, Canada
| | - Peter Beckett
- School of Natural Sciences and the Vale Living with Lakes Centre, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Shaun A Watmough
- School of the Environment, Trent University, Peterborough, ON, K9L 0G2, Canada
| |
Collapse
|
5
|
Stuart JEM, Tucker CL, Lilleskov EA, Kolka RK, Chimner RA, Heckman KA, Kane ES. Evidence for older carbon loss with lowered water tables and changing plant functional groups in peatlands. GLOBAL CHANGE BIOLOGY 2023; 29:780-793. [PMID: 36308039 DOI: 10.1111/gcb.16508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
A small imbalance in plant productivity and decomposition accounts for the carbon (C) accumulation capacity of peatlands. As climate changes, the continuity of peatland net C storage relies on rising primary production to offset increasing ecosystem respiration (ER) along with the persistence of older C in waterlogged peat. A lowering in the water table position in peatlands often increases decomposition rates, but concurrent plant community shifts can interactively alter ER and plant productivity responses. The combined effects of water table variation and plant communities on older peat C loss are unknown. We used a full-factorial 1-m3 mesocosm array with vascular plant functional group manipulations (Unmanipulated Control, Sedge only, and Ericaceous only) and water table depth (natural and lowered) treatments to test the effects of plants and water depth on CO2 fluxes, decomposition, and older C loss. We used Δ14 C and δ13 C of ecosystem CO2 respiration, bulk peat, plants, and porewater dissolved inorganic C to construct mixing models partitioning ER among potential sources. We found that the lowered water table treatments were respiring C fixed before the bomb spike (1955) from deep waterlogged peat. Lowered water table Sedge treatments had the oldest dissolved inorganic 14 C signature and the highest proportional peat contribution to ER. Decomposition assays corroborated sustained high rates of decomposition with lowered water tables down to 40 cm below the peat surface. Heterotrophic respiration exceeded plant respiration at the height of the growing season in lowered water table treatments. Rates of gross primary production were only impacted by vegetation, whereas ER was affected by vegetation and water table depth treatments. The decoupling of respiration and primary production with lowered water tables combined with older C losses suggests that climate and land-use-induced changes in peatland hydrology can increase the vulnerability of peatland C stores.
Collapse
Affiliation(s)
- Julia E M Stuart
- College of Forest Resources and Environmental Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Colin L Tucker
- USDA Forest Service Northern Research Station, Climate, Fire and Carbon Cycle Sciences Unit (NRS-6), Houghton, Michigan, USA
| | - Erik A Lilleskov
- USDA Forest Service Northern Research Station, Climate, Fire and Carbon Cycle Sciences Unit (NRS-6), Houghton, Michigan, USA
| | - Randall K Kolka
- USDA Forest Service Northern Research Station, Forestry Sciences Lab, Grand Rapids, Minnesota, USA
| | - Rodney A Chimner
- College of Forest Resources and Environmental Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Katherine A Heckman
- USDA Forest Service Northern Research Station, Climate, Fire and Carbon Cycle Sciences Unit (NRS-6), Houghton, Michigan, USA
| | - Evan S Kane
- College of Forest Resources and Environmental Sciences, Michigan Technological University, Houghton, Michigan, USA
- USDA Forest Service Northern Research Station, Climate, Fire and Carbon Cycle Sciences Unit (NRS-6), Houghton, Michigan, USA
| |
Collapse
|
6
|
Zhang Y, Song C, Wang X, Chen N, Zhang H, Du Y, Zhang Z, Zhu X. Warming effects on the flux of CH 4 from peatland mesocosms are regulated by plant species composition: Richness and functional types. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150831. [PMID: 34627884 DOI: 10.1016/j.scitotenv.2021.150831] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/27/2021] [Accepted: 10/02/2021] [Indexed: 06/13/2023]
Abstract
Peatlands in northeast China are experiencing severe climate warming. Most studies on peatlands focus on the responses of CH4 dynamics to temperature. However, they rarely consider the synchronous changes in the composition of plant communities caused by the expansion of vascular plants. In this study, an experiment combined warming with the manipulation of plants to examine the concentrations of CH4 porewater and its fluxes in the mesocosm. We found that warming increased the concentration of CH4 and its fluxes relative to the control treatments, and it was strongly modulated by plant richness and functional types. The average CH4 fluxes in the warming and non-warming mesocosms varied from 72.10 to 119.44 and 97.95 to 194.43 mg m-2 h-1, respectively. Plant species richness significantly increased CH4 flux at the warming level of 3.2 °C (P < 0.01). The presence of vascular plants, such as Carex globularis and Vaccinium uliginosum, significantly increased the CH4 fluxes after warming had occurred. Our results suggest that the distinct response of CH4 to richness and species primarily stemmed from the direct or indirect effects of plant biomass and functional characteristics. Therefore, more consideration should be given to the diversity changes caused by vascular plant expansion when estimating CH4 flux in boreal peatland, especially in the context of future climate warming.
Collapse
Affiliation(s)
- Yifei Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changchun Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; School of Hydraulic Engineering, Dalian University of Technology, Dalian 116023, China.
| | - Xianwei Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Ning Chen
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Hao Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Yu Du
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Zhengang Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinhao Zhu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| |
Collapse
|
7
|
Shao S, Wu J, He H, Roulet N. Integrating McGill Wetland Model (MWM) with peat cohort tracking and microbial controls. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151223. [PMID: 34717989 DOI: 10.1016/j.scitotenv.2021.151223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/11/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
Peatlands store a large amount of organic carbon and are vulnerable to climate change and human disturbances. However, ecosystem-scale peatland models often do not explicitly simulate the decrease in peat substrate quality, i.e., decomposability or the dynamics of decomposers during peat decomposition, which are key controls in determining peat carbon's response to a changing environment. In this paper, we incorporated the tracking of each year's litter input (a cohort) and controls of microbial processes into the McGill Wetland Model (MWMmic) to address this discrepancy. Three major modifications were made: (1) the simple acrotelm-catotelm decomposition model in MWM was changed into a time-aggregated cohort model, to track the decrease in peat quality with decomposition age; (2) microbial dynamics: growth, respiration and death were incorporated into the model and decomposition rates are regulated by microbial biomass; and (3) vertical and horizontal transport of the dissolved organic carbon (DOC) were added and used to regulate the growth of microbial biomass. MWMmic was evaluated against measurements from the Mer Bleue peatland, a raised ombrotrophic bog located in southern Ontario, Canada. The model was able to replicate microbial and DOC dynamics, while at the same time reproduce the ecosystem-level CO2 and DOC fluxes. Sensitivity analysis with MWMmic showed increased peatland resilience to perturbations compared to the original MWM, because of the tracking of peat substrate quality. The analysis revealed the most important parameters in the model to be microbial carbon use efficiency (CUE) and turnover rate. Simulated microbial adaptation with those two physiological parameters less sensitive to disturbances leads to a significantly larger peat C loss in response to warming and water table drawdown. Thus, the rarely explored peatland microbial physiological traits merit further research. This work paves the way for further model development to examine important microbial controls on peatland's biogeochemical cycling.
Collapse
Affiliation(s)
- Siya Shao
- Department of Geography, McGill University, Canada
| | - Jianghua Wu
- Environment and Sustainability, School of Science and the Environment, Memorial University of Newfoundland, Canada
| | - Hongxing He
- Department of Geography, McGill University, Canada
| | - Nigel Roulet
- Department of Geography, McGill University, Canada.
| |
Collapse
|
8
|
Kolari THM, Korpelainen P, Kumpula T, Tahvanainen T. Accelerated vegetation succession but no hydrological change in a boreal fen during 20 years of recent climate change. Ecol Evol 2021; 11:7602-7621. [PMID: 34188838 PMCID: PMC8216969 DOI: 10.1002/ece3.7592] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/26/2021] [Accepted: 04/01/2021] [Indexed: 11/17/2022] Open
Abstract
Northern mires (fens and bogs) have significant climate feedbacks and contribute to biodiversity, providing habitats to specialized biota. Many studies have found drying and degradation of bogs in response to climate change, while northern fens have received less attention. Rich fens are particularly important to biodiversity, but subject to global climate change, fen ecosystems may change via direct response of vegetation or indirectly by hydrological changes. With repeated sampling over the past 20 years, we aim to reveal trends in hydrology and vegetation in a pristine boreal fen with gradient from rich to poor fen and bog vegetation. We resampled 203 semi-permanent plots and compared water-table depth (WTD), pH, concentrations of mineral elements, and dissolved organic carbon (DOC), plant species occurrences, community structure, and vegetation types between 1998 and 2018. In the study area, the annual mean temperature rose by 1.0°C and precipitation by 46 mm, in 20-year periods prior to sampling occasions. We found that wet fen vegetation decreased, while bog and poor fen vegetation increased significantly. This reflected a trend of increasing abundance of common, generalist hummock species at the expense of fen specialist species. Changes were the most pronounced in high pH plots, where Sphagnum mosses had significantly increased in plot frequency, cover, and species richness. Changes of water chemistry were mainly insignificant in concentration levels and spatial patterns. Although indications toward drier conditions were found in vegetation, WTD had not consistently increased, instead, our results revealed complex dynamics of WTD as depending on vegetation changes. Overall, we found significant trend in vegetation, conforming to common succession pattern from rich to poor fen and bog vegetation. Our results suggest that responses intrinsic to vegetation, such as increased productivity or altered species interactions, may be more significant than indirect effects via local hydrology to the ecosystem response to climate warming.
Collapse
Affiliation(s)
- Tiina H. M. Kolari
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandJoensuuFinland
| | - Pasi Korpelainen
- Department of Geographical and Historical StudiesUniversity of Eastern FinlandJoensuuFinland
| | - Timo Kumpula
- Department of Geographical and Historical StudiesUniversity of Eastern FinlandJoensuuFinland
| | - Teemu Tahvanainen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandJoensuuFinland
| |
Collapse
|
9
|
Jassey VEJ, Signarbieux C. Effects of climate warming on Sphagnum photosynthesis in peatlands depend on peat moisture and species-specific anatomical traits. GLOBAL CHANGE BIOLOGY 2019; 25:3859-3870. [PMID: 31502398 DOI: 10.1111/gcb.14788] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/16/2019] [Indexed: 06/10/2023]
Abstract
Climate change will influence plant photosynthesis by altering patterns of temperature and precipitation, including their variability and seasonality. Both effects may be important for peatlands as the carbon (C) sink potential of these ecosystems depends on the balance between plant C uptake through photosynthesis and microbial decomposition. Here, we show that the effect of climate warming on Sphagnum community photosynthesis toggles from positive to negative as the peatland goes from rainy to dry periods during summer. More particularly, we show that mechanisms of compensation among the dominant Sphagnum species (Sphagnum fallax and Sphagnum medium) stabilize the average photosynthesis and productivity of the Sphagnum community during summer despite rising temperatures and frequent droughts. While warming had a negligible effect on S. medium photosynthetic capacity (Amax ) during rainy periods, Amax of S. fallax increased by 40%. On the opposite, warming exacerbated the negative effects of droughts on S. fallax with an even sharper decrease of its Amax while S. medium Amax remained unchanged. S. medium showed a remarkable resistance to droughts due to anatomical traits favouring its water holding capacity. Our results show that different phenotypic plasticity among dominant Sphagnum species allow the community to cope with rising temperatures and repeated droughts, maintaining similar photosynthesis and productivity over summer in warmed and control conditions. These results are important because they provide information on how soil water content may modulate the effects of climate warming on Sphagnum productivity in boreal peatlands. It further confirms the transitory nature of warming-induced photosynthesis benefits in boreal systems and highlights the vulnerability of the ecosystem to excess warming and drying.
Collapse
Affiliation(s)
- Vincent E J Jassey
- Laboratoire d'Ecologie Fonctionnelle et Environnement, CNRS-INPT, Université de Toulouse, Toulouse, France
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecological Systems Laboratory (ECOS), Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Lausanne, Switzerland
| | - Constant Signarbieux
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecological Systems Laboratory (ECOS), Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Lausanne, Switzerland
- Institute of Geography, University of Neuchatel, Neuchatel, Switzerland
| |
Collapse
|
10
|
Hill PW, Broughton R, Bougoure J, Havelange W, Newsham KK, Grant H, Murphy DV, Clode P, Ramayah S, Marsden KA, Quilliam RS, Roberts P, Brown C, Read DJ, Deluca TH, Bardgett RD, Hopkins DW, Jones DL. Angiosperm symbioses with non-mycorrhizal fungal partners enhance N acquisition from ancient organic matter in a warming maritime Antarctic. Ecol Lett 2019; 22:2111-2119. [PMID: 31621153 PMCID: PMC6899649 DOI: 10.1111/ele.13399] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/26/2019] [Accepted: 09/10/2019] [Indexed: 01/01/2023]
Abstract
In contrast to the situation in plants inhabiting most of the world’s ecosystems, mycorrhizal fungi are usually absent from roots of the only two native vascular plant species of maritime Antarctica, Deschampsia antarctica and Colobanthus quitensis. Instead, a range of ascomycete fungi, termed dark septate endophytes (DSEs), frequently colonise the roots of these plant species. We demonstrate that colonisation of Antarctic vascular plants by DSEs facilitates not only the acquisition of organic nitrogen as early protein breakdown products, but also as non‐proteinaceous d‐amino acids and their short peptides, accumulated in slowly‐decomposing organic matter, such as moss peat. Our findings suggest that, in a warming maritime Antarctic, this symbiosis has a key role in accelerating the replacement of formerly dominant moss communities by vascular plants, and in increasing the rate at which ancient carbon stores laid down as moss peat over centuries or millennia are returned to the atmosphere as CO2.
Collapse
Affiliation(s)
- Paul W Hill
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Richard Broughton
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 OET, UK.,Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Jeremy Bougoure
- Faculty of Science, SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, 6009, Australia.,Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, WA, 6009, Australia
| | | | - Kevin K Newsham
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 OET, UK
| | - Helen Grant
- Life Sciences Mass Spectrometry Facility, Lancaster Environment Centre, Lancaster, LA1 4AP, UK
| | - Daniel V Murphy
- Faculty of Science, SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, 6009, Australia
| | - Peta Clode
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, WA, 6009, Australia.,UWA School of Biological Sciences, University of Western Australia, Crawley, WA, 6009, Australia
| | - Soshila Ramayah
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Karina A Marsden
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Vic., 3010, Australia
| | - Richard S Quilliam
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Paula Roberts
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Caley Brown
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - David J Read
- Animal and Plant Sciences, University of Sheffield, Western bank, Sheffield, S10 2TN, UK
| | - Thomas H Deluca
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, 59812, USA
| | - Richard D Bardgett
- School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK
| | - David W Hopkins
- SRUC - Scotland's Rural College, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Davey L Jones
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.,Faculty of Science, SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, 6009, Australia
| |
Collapse
|
11
|
Laine AM, Mäkiranta P, Laiho R, Mehtätalo L, Penttilä T, Korrensalo A, Minkkinen K, Fritze H, Tuittila ES. Warming impacts on boreal fen CO 2 exchange under wet and dry conditions. GLOBAL CHANGE BIOLOGY 2019; 25:1995-2008. [PMID: 30854735 DOI: 10.1111/gcb.14617] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/11/2019] [Accepted: 02/21/2019] [Indexed: 05/14/2023]
Abstract
Northern peatlands form a major soil carbon (C) stock. With climate change, peatland C mineralization is expected to increase, which in turn would accelerate climate change. A particularity of peatlands is the importance of soil aeration, which regulates peatland functioning and likely modulates the responses to warming climate. Our aim is to assess the impacts of warming on a southern boreal and a sub-arctic sedge fen carbon dioxide (CO2 ) exchange under two plausible water table regimes: wet and moderately dry. We focused this study on minerotrophic treeless sedge fens, as they are common peatland types at boreal and (sub)arctic areas, which are expected to face the highest rates of climate warming. In addition, fens are expected to respond to environmental changes faster than the nutrient poor bogs. Our study confirmed that CO2 exchange is more strongly affected by drying than warming. Experimental water level draw-down (WLD) significantly increased gross photosynthesis and ecosystem respiration. Warming alone had insignificant impacts on the CO2 exchange components, but when combined with WLD it further increased ecosystem respiration. In the southern fen, CO2 uptake decreased due to WLD, which was amplified by warming, while at northern fen it remained stable. As a conclusion, our results suggest that a very small difference in the WLD may be decisive, whether the C sink of a fen decreases, or whether the system is able to adapt within its regime and maintain its functions. Moreover, the water table has a role in determining how much the increased temperature impacts the CO2 exchange.
Collapse
Affiliation(s)
- Anna M Laine
- School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
| | | | - Raija Laiho
- Natural Resources Institute Finland, Helsinki, Finland
| | - Lauri Mehtätalo
- School of Computing, University of Eastern Finland, Joensuu, Finland
| | - Timo Penttilä
- Natural Resources Institute Finland, Helsinki, Finland
| | - Aino Korrensalo
- School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
| | - Kari Minkkinen
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Hannu Fritze
- Natural Resources Institute Finland, Helsinki, Finland
| | | |
Collapse
|
12
|
Combination of Warming and Vegetation Composition Change Strengthens the Environmental Controls on N2O Fluxes in a Boreal Peatland. ATMOSPHERE 2018. [DOI: 10.3390/atmos9120480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Climate warming and vegetation composition change are expected to influence greenhouse gas emissions from boreal peatlands. However, the interactive effects of warming and different vegetation compositions on N2O dynamics are poorly known, although N2O is a very potent greenhouse gas. In this study, manipulated warming and vegetation composition change were conducted in a boreal peatland to investigate the effects on N2O fluxes during the growing seasons in 2015 and 2016. We did not find a significant effect of warming treatment and combination treatments of warming and vegetation composition change on N2O fluxes. However, sedge removal treatment significantly increased N2O emissions by three-fold. Compared with the treatment of shrub and sedge removal, the combined treatment of warming and shrub and sedge removal significantly increased N2O consumption by five-fold. Similar to N2O fluxes, the cumulative N2O flux increased by ~3.5 times under sedge removal treatment, but this effect was not significant. In addition, the results showed that total soil nitrogen was the main control for N2O fluxes under combinative treatments of warming and sedge/shrub removal, while soil temperature and dissolved organic carbon were the main controls for N2O release under warming combined with the removal of all vascular plants. Our results indicate that boreal peatlands have a negligible effect on N2O fluxes in the short-term under climate change, and environmental controls on N2O fluxes become increasingly important under the condition of warming and vegetation composition change.
Collapse
|