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61.
Hilde B.M. Tomassen Alfons J.P. Smolders Leon P.M. Lamers Jan G.M. Roelofs 《Biogeochemistry》2005,71(1):69-87
The usual method of restoring cut-over bogs is to rewet the peat surface, but this often leads to the remaining peat layers being deeply inundated. For Sphagnum-dominated vegetation to develop at deeply inundated locations, it is important for floating rafts of buoyant residual peat to develop. In this study, the chemical and physical characteristics of buoyant and inundated peat collected from rewetted cut-over bog were compared. In general, buoyant peat was poorly humified; high methane (CH4) production rates (2 µmol g –1 DW day –1) were important to ensure buoyancy. Although the peat water CH4 concentrations increased with depth, the CH4 production rates were higher in the uppermost peat layers. High CH4 production rates were related positively with P concentrations and negatively with lignin concentrations. The pH to bulk density ratio (0.05) also appeared to be a good indicator of CH4 production rates, providing an easy and cheap way to measure the variable for restoration practitioners. Our results indicated that analysing certain simple characteristics of the residual peat can greatly improve the success of the rewetting measures taken in cut-over bogs. If the analysis reveals that the residual peat is unsuitable for floating raft formation, deep inundation is inappropriate unless suitable peat from other locations can be introduced. 相似文献
62.
We determined evapotranspiration in three experiments designed to study the effects of elevated CO2 and increased N deposition on ombrotrophic bog vegetation. Two experiments used peat monoliths with intact bog vegetation in containers, with one experiment outdoors and the other in a greenhouse. A third experiment involved monocultures and mixtures of Sphagnum magellanicum and Eriophorum angustifolium in containers in the same greenhouse. To determine water use of the bog vegetation in July–August for each experiment and each year we measured water inputs and outputs from the containers. We studied the effects of elevated CO2 and N supply on evapotranspiration in relation to vascular plant biomass and exposure of the moss surface (measured as height of the moss surface relative to the container edge). Elevated CO2 reduced water use of the bog vegetation in all three experiments, but the CO2 effect on evapotranspiration interacted with vascular plant biomass and exposure of the moss surface. Evapotranspiration in the outdoor experiment was largely determined by evaporation from the Sphagnum moss surface (as affected by exposure to wind) and less so by vascular plant transpiration. Nevertheless, elevated CO2 significantly reduced evapotranspiration by 9–10% in the outdoor experiment. Vascular plants reduced evapotranspiration in the outdoor experiment, but increased water use in the greenhouse experiments. The relation between vascular plant abundance and evapotranspiration appears to depend on wind conditions; suggesting that vascular plants reduce water losses mainly by reducing wind speed at the moss surface. Sphagnum growth is very sensitive to changes in water level; low water availability can have deleterious effects. As a consequence, reduced evapotranspiration in summer, whether caused by elevated CO2 or by small increases in vascular plant cover, is expected to favour Sphagnum growth in ombrotrophic bog vegetation. 相似文献
63.
Emissions of methane from northern peatlands: a review of management impacts and implications for future management options 总被引:1,自引:0,他引:1
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Mohamed Abdalla Astley Hastings Jaak Truu Mikk Espenberg Ülo Mander Pete Smith 《Ecology and evolution》2016,6(19):7080-7102
Northern peatlands constitute a significant source of atmospheric methane (CH4). However, management of undisturbed peatlands, as well as the restoration of disturbed peatlands, will alter the exchange of CH4 with the atmosphere. The aim of this systematic review and meta‐analysis was to collate and analyze published studies to improve our understanding of the factors that control CH4 emissions and the impacts of management on the gas flux from northern (latitude 40° to 70°N) peatlands. The analysis includes a total of 87 studies reporting measurements of CH4 emissions taken at 186 sites covering different countries, peatland types, and management systems. Results show that CH4 emissions from natural northern peatlands are highly variable with a 95% CI of 7.6–15.7 g C m?2 year?1 for the mean and 3.3–6.3 g C m?2 year?1 for the median. The overall annual average (mean ± SD) is 12 ± 21 g C m?2 year?1 with the highest emissions from fen ecosystems. Methane emissions from natural peatlands are mainly controlled by water table (WT) depth, plant community composition, and soil pH. Although mean annual air temperature is not a good predictor of CH4 emissions by itself, the interaction between temperature, plant community cover, WT depth, and soil pH is important. According to short‐term forecasts of climate change, these complex interactions will be the main determinant of CH4 emissions from northern peatlands. Drainage significantly (p < .05) reduces CH4 emissions to the atmosphere, on average by 84%. Restoration of drained peatlands by rewetting or vegetation/rewetting increases CH4 emissions on average by 46% compared to the original premanagement CH4 fluxes. However, to fully evaluate the net effect of management practice on the greenhouse gas balance from high latitude peatlands, both net ecosystem exchange (NEE) and carbon exports need to be considered. 相似文献
64.
Yoshikazu Shimizu 《Ecological Research》1986,1(2):185-194
Species-area relationships of flowering plants were analyzed on the habitat-islands (hummocks on a floating bog) of Mizorogaike
Pond, Japan. Three habitat units (Sphagnum cuspidatum unit,Sphagnum palustre unit, and fallen leaves unit) in which habitat conditions were homogeneous and a group of habitat-specific species occurred
were recognized on the hummocks. Six hummock types were determined according to various combinations of the three habitat
units. The most fundamental species-area relationships in which size itself affects the number of species were shown by hummocks
with only one habitat unit. The species-area relationships for hummocks with two or three habitat units included the effects
of habitat diversity in addition to size. The speciesarea curve for all hummocks was an average of these relationships. It
is concluded that area in species-area relationships affects species numbers in two ways: number of habitat units and size
of each habitat unit. 相似文献
65.
Associations of diatoms in the surficial sediments of lakes and peat pools in Atlantic Canada 总被引:1,自引:1,他引:0
The distribution of diatom frustules in the surficial sediments of lakes and ombrotrophic peat pools in Atlantic Canada are examined especially in relation to pH and bog lake succession. Sedimentary diatom associations for peat pools, strongly acidic lakes, and weakly acidic lakes are characterized. These associations and the derived diatom-pH calibration functions will facilitate improved paleoecological interpretation of natural ontogenetic pathways and assessments of recent anthropogenic impacts. 相似文献
66.
Modelling and analysis of peatlands as dynamical systems 总被引:8,自引:0,他引:8
67.
68.
Effects of short-term changes in rain water supply on the ionic composition of acid moorland pools in the Campine of Antwerp (Belgium) 总被引:1,自引:1,他引:0
A study was made on the change of pH, corrected conductivity, Na, K, Ca, Mg, Cl and SO4 with time over a period of 3.5 years (autumn 1975-spring 1979) in 21 very acid shallow bogs in the Campine of Antwerp (North of Belgium). These moorland pools are subjected to severe changes in waterlevel due to the fact that they depend mostly on rainwater for their water supply. Subsequently the very hot and dry summer of 1976 made the waterlevel to decrease and some pools even became totally dry. The concomitant changes in the ionic concentrations and in the ionic composition have been studied in detail and are summarized in this paper.Belgian Nuclear Center SCK-CEN: Radiobiology department, Radionuclides Metabolism SectionAddress for reprint requests 相似文献
69.
The abilities of some ascomycetes (Myxotrichaceae) from a Sphagnum bog in Alberta to degrade cellulose, phenolics, and Sphagnum tissue were compared with those of two basidiomycetes. Most Myxotrichaceae degraded cellulose and tannic acid, and removed cell-wall components simultaneously from Sphagnum tissues, whereas the basidiomycetes degraded cellulose and insoluble phenolics, and preferentially removed the polyphenolic matrix from Sphagnum cell walls. Mass losses from Sphagnum varied from up to 50% for some ascomycetes to a maximum of 35% for the basidiomycetes. The decomposition of Sphagnum by the Myxotrichaceae was analogous to the white rot of wood and indicates that these fungi have the potential to cause significant mineralization of carbon in bogs. 相似文献
70.
Carbon dioxide and methane (CH4) fluxes were measured in a cutover bog of the Jura Mountains (France) together with biotic and abiotic variables for two entire vegetation periods in order to compare the carbon balance of the bog at three stages of regeneration. Among all factors, air temperature and vegetation index (including leaf area of vascular plants, bryophyte density and bryophyte desiccation) were the two main determinants of ecosystem respiration and gross photosynthesis at light saturation. During 2004 and 2005, the vegetated plots acted as carbon sinks. Net carbon exchange ranged between 67 and 166 g C m(-2) yr(-1) for the Eriophorum-dominated plots and between 93 and 183 g C m(-2) yr(-1) for the Sphagnum-dominated plots. The bare peat plots represented a net carbon source (between -19 and -32 g C m(-2) yr(-1)). Methane fluxes accounted for a very small part of the total carbon efflux (< 2%). The recovery of vegetation in our naturally regenerating bog was beneficial for the carbon sequestration after the relatively short period of 20 yr. 相似文献