植物残体与泥炭和泥炭矿体分类的初步探讨

泥炭植物残体是泥炭和泥炭矿体的主要组分。泥炭的植物组成与泥炭的分解度和营养状况密切相关。在进行泥炭分类时,植物残体组成是其重要依据。各泥炭矿体特征间“质”的差异也反映在泥炭植物残体组成成分的不同上。因此,在进行泥炭矿体分类时,可将矿层的植物残体组分作其依据。本文拟将我国的泥炭矿体分为富营养、中营养、贫营养和混合四个泥炭矿体型;并续分出十一个泥炭矿体组。     

地理来源与生物化学属性对泥炭地植物残体分解的影响

不同地理来源的泥炭地植物残体在同一环境中的分解速率一直缺乏比较研究。该研究沿纬度梯度, 选择大九湖、哈泥和满归3处泥炭地, 以三地的10种植物为分解材料, 使用分解袋包装, 埋藏于长白山哈泥泥炭地, 开展为期1年的分解实验, 研究地理来源及生物化学属性对泥炭地植物残体分解的影响。结果表明, 如不考虑物种差异, 从总体上看, 随着纬度增加, 3处泥炭地植物残体的初始氮(N)含量下降, 初始木质素含量、碳氮比(C/N)和木质素/N上升。经一年分解后残体分解速率因植物类群不同而不同, 桦木属(Betula)和薹草属(Carex)植物残体的干质量损失率均接近50%, 远大于泥炭藓属(Sphagnum)植物(约为10%)。3处来源地植物残体干质量损失率总体上无差异, 但比较同种植物残体发现, 来自中纬度泥炭地哈泥的中位泥炭藓(S. magellanicum)的干质量损失率(19%)远高于来自高纬度泥炭地满归的(9%)。制约残体分解的因素因植物类群不同而不同, 残体初始总酚/N是决定属间残体干质量损失率差异的重要指标。薹草属植物初始N含量和C/N与残体分解速率、泥炭藓属植物初始Klason木质素含量和总酚/N与残体分解速率均呈正相关关系。该研究一定程度上表明, 若以纬度降低指代气候变暖, 当前持续的气候变暖可能通过改变高纬度泥炭地的植物组成和植物的生物化学属性, 来改变植物残体分解速率, 进而影响泥炭地的碳汇功能。     

Effect of geographical sources and biochemical traits on plant litter decomposition in a peatland

不同地理来源的泥炭地植物残体在同一环境中的分解速率一直缺乏比较研究。该研究沿纬度梯度, 选择大九湖、哈泥和满归3处泥炭地, 以三地的10种植物为分解材料, 使用分解袋包装, 埋藏于长白山哈泥泥炭地, 开展为期1年的分解实验, 研究地理来源及生物化学属性对泥炭地植物残体分解的影响。结果表明, 如不考虑物种差异, 从总体上看, 随着纬度增加, 3处泥炭地植物残体的初始氮(N)含量下降, 初始木质素含量、碳氮比(C/N)和木质素/N上升。经一年分解后残体分解速率因植物类群不同而不同, 桦木属(Betula)和薹草属(Carex)植物残体的干质量损失率均接近50%, 远大于泥炭藓属(Sphagnum)植物(约为10%)。3处来源地植物残体干质量损失率总体上无差异, 但比较同种植物残体发现, 来自中纬度泥炭地哈泥的中位泥炭藓(S. magellanicum)的干质量损失率(19%)远高于来自高纬度泥炭地满归的(9%)。制约残体分解的因素因植物类群不同而不同, 残体初始总酚/N是决定属间残体干质量损失率差异的重要指标。薹草属植物初始N含量和C/N与残体分解速率、泥炭藓属植物初始Klason木质素含量和总酚/N与残体分解速率均呈正相关关系。该研究一定程度上表明, 若以纬度降低指代气候变暖, 当前持续的气候变暖可能通过改变高纬度泥炭地的植物组成和植物的生物化学属性, 来改变植物残体分解速率, 进而影响泥炭地的碳汇功能。     

内蒙古乌达煤田下二叠统山西组4,5号煤层底板植物群研究北大核心CSCD

基于对内蒙古乌达煤田下二叠统山西组4,5号煤层底板的野外工作,系统采集、鉴定植物化石18属26种,其中以华夏植物群的特有属种或常见分子占绝对优势。沉积环境及植物古生态学分析表明,5号煤底板植物群主要由Lepidodendron posthumii Jongm. and Goth.和Cathaysiodendron cf.incertum(Sze and Lee) Lee等组成,代表了三角洲平原上碎屑沼泽植被景观。4号煤底板植物群主要由成煤沼泽植物和碎屑沼泽植物混合而成,原位埋藏的Stigmaria ficoides(Sternb.) Brongn.为成煤沼泽植被类群,代表了上覆4号煤的成煤植物;由Tingia carbonica(Schenk) Halle和Pecopteris arborescens(Schloth.) Sternb.等组成的碎屑沼泽植被类群,代表了三角洲平原上的碎屑沼泽植被景观。综合相关研究资料和当前植物化石分析表明,煤层底板植物群主要代表了地质历史时期中的湿地植被,按照其与形成上覆煤层植物之间的关系可主要分为:上覆煤层形成初期的泥炭沼泽植物群、与成煤作用无关的碎屑沼泽植物群和两者的混合类型。底板植物群的深入研究必须要结合沉积岩石学、地层学以及埋藏学的分析。当前研究显示乌达地区早二叠世沉积时期,湿地植被组成较为稳定,其中石松类植物一直都是重要的成煤泥炭沼泽植被类型;碎屑沼泽植被与成煤沼泽植被多数情况下成分类似,仅存在种一级别的差异。     

多指标记录的1962—2008年长白山园池泥炭地地表湿度变化

使用AMS ¹⁴C和¹³⁷Cs方法建立年代序列,通过植物残体、有壳变形虫和腐殖化度3个指标的综合分析,重建了长白山园池泥炭地地表的湿度变化,并探讨其对气候的响应。结果表明: 园池泥炭地地表50 cm泥炭植物残体以藓类为主,利用去趋势对应分析(DCA)发现,第一轴得分代表沼泽表面湿度变化,将植物残体揭示的1962—2008 A.D.间泥炭地地表湿度与有壳变形虫-水位间转换函数得到的水位埋深以及腐殖化度进行对比,发现植物残体、有壳变形虫和腐殖化度揭示的沼泽表面湿度变化总体趋势一致,即40～50 cm层(1962—1975 A.D.)湿度较大;27～40 cm层(1975—1987 A.D.)湿度变小,处于干湿交替期;0～27 cm层(1987—2008 A.D.)湿度较小。将3种指标重建的地表湿度与二道气象站数据对比发现,气候代用指标揭示的沼泽地表湿度变化与温度的变化趋势基本吻合,沼泽地地表湿度降低发生在夏季温度和年均温偏高的年份。由此推测,近46年来沼泽地地表湿度变化主要是对温度升高引起的有效降水减弱的响应。     

泥炭植物残体的研究方法

泥炭是一种宝贵的自然资源,主要由植物残体、腐殖质、矿物质和大量水分组成,以矿体的形式分布世界各地。我国泥炭资源丰富,面积估计约为415.9万公顷,占世界第七位;泥炭总储量估算为     

小兴安岭兴安落叶松泥炭藓沼泽植物的主要微量元素

小兴安岭兴安落叶松、泥炭藓沼泽是我国典型贫营养型沼泽。沼泽中树木生长发育不良,泥炭藓和常绿小灌木发育十分良好。这与沼泽水文状况和泥炭中营养元素和微量元素有关。各种植物的主要微量元素硼、铜、钴、锰、锌等含量不同,植物的不同器官中的含量亦不同,而且随季节而变化。狭叶杜香和甸杜的主要微量元素含量特点及其季节变化规律基本相似,两种泥炭藓相似,都与兴安落叶松有明显的区别。 本文重点探讨植物体内主要微量元素及其含量变化规律,为揭示贫营养型森林沼泽生态、为合理利用与改造沼泽提供依据。     

东北哈泥泥炭地不同泥炭藓属植物高光谱特征

泥炭藓是北方泥炭地的优势植物,其高光谱特征研究很少。本研究采用高光谱遥感技术,对不同水位埋深条件下(藓丘及丘间)生长的相同种类泥炭藓植物,及同一水位埋深条件下的不同种类泥炭藓植物的光谱特征进行研究。结果表明,不同种类泥炭藓属植物的光谱反射特征具有明显种间差异,主要反映在绿峰、红边的差异上。由于水分条件差异,生长在高丘和低丘的锈色泥炭藓、泥炭藓及中位泥炭藓在可见光和近红外波段的光谱反射率均具有显著差异,高丘的泥炭藓属植物的反射率均高于低丘的泥炭藓属植物。本研究所获得的东北地区哈泥泥炭地几种泥炭藓属植物的详细光谱信息,可以为高分辨率航空影像和卫片解译泥炭藓湿地提供地面基础。     

基于MODIS数据的神农架大九湖泥炭藓沼泽植被指数变化研究

泥炭藓是陆地生态系统中最重要的固碳植物之一,固碳量约占全球土壤碳的15%。近几十年来,由全球气候变暖导致的泥炭藓沼泽水热状况变化对泥炭藓的固碳量和速率产生影响。选取我国最重要的亚高山泥炭沼泽——神农架大九湖泥炭藓沼泽为试验区,以分析中纬度地区泥炭藓沼泽植被生长状况受气候变化的影响。研究以2000—2017年MODIS植被指数NDVI和EVI为数据源,通过对比Logistic模型订正后的NDVI和EVI时间序列在泥炭藓沼泽植被生长状况监测中的优劣,选出最佳指标以获得18年来泥炭藓沼泽植被生长状况的变化趋势。研究结果表明:1)Logistic模型能够很好的消除泥炭藓沼泽植被指数时间序列的噪声;2)在季节和年际两个时间尺度上,EVI对泥炭藓沼泽植被生长状况的监测效果均优于NDVI。在季节周期上,虽然EVI和NDVI均得到泥炭藓沼泽植被生长周期规律,但EVI更灵敏。在年际分析中,EVI有更大的值域响应空间,以准确反映泥炭藓沼泽植被的年际变化规律;3)由EVI获得18年来泥炭藓沼泽植被变化趋势指出,泥炭藓沼泽植被呈显著微弱增长,年均EVI增长率为3.8‰(R~2=0.45,P0.01)。相比于EVI年均值,EVI年内最大值(R~2=0.47,P0.01)更敏锐的反映泥炭藓沼泽植被生长状况的动态变化。     

贵州麻若平台泥炭藓沼泽中泥炭藓持水特性及其与土壤营养元素关系研究

泥炭藓属(Sphagnum)植物的持水特性在泥炭湿地形成过程中起着重要作用,研究其与土壤营养元素之间的关系有助于地区湿地保护和退化湿地的修复。以贵州麻若平台分布的泥炭沼泽为对象,采用方差分析、相关性分析和冗余分析等方法对沼泽内泥炭藓的生物量、蓄水量、吸水率和土壤营养元素含量等进行研究。结果显示,该区域泥炭藓物种组成主要包括狭叶泥炭藓(Sphagnum cuspidatum Ehrh.)、多纹泥炭藓(Sphagnum multifibrosum X. J. LiM. Zang)和卵叶泥炭藓(Sphagnum ovatum Hampe.) 3种,狭叶泥炭藓为优势种,占泥炭藓总盖度的87.2%。沼泽中泥炭藓的生物量为(0.62±0.01) kg/m~2,自然蓄水量为(9.42±0.45) kg/m~2,饱和吸水率达1827.41%±34.56%,说明泥炭藓具有很强的持水能力。RDA分析表明,泥炭藓的生物量、饱和吸水量和饱和吸水率主要受沼泽土壤总钾、总磷、有效磷、有效氮、有效钾的影响,泥炭藓的鲜重、自然蓄水量和自然吸水率受土壤pH和水位的影响较大。泥炭藓的生物量、饱和蓄水量、饱和吸水率与土壤总钾含量呈正相关,与土壤总磷、有效磷、总钾、有效氮、总氮、有机质含量呈负相关,说明土壤总磷、有效磷、有效钾、有效氮、总氮、有机质对沼泽中泥炭藓的持水能力具有抑制作用。     

Headwater Mires Constitute a Major Source of Nitrogen (N) to Surface Waters in the Boreal Landscape

Nutrient exports from soils have important implications for long-term patterns of nutrient limitation on land and resource delivery to aquatic environments. While plant–soil systems are notably efficient at retaining limiting nutrients, spatial and temporal mismatches in resource supply and demand may create opportunities for hydrologic losses to occur. Spatial mismatches may be particularly important in peat-forming landscapes, where the development of a two-layer vertical structure can isolate plant communities on the surface from resource pools that accumulate at depth. Our objectives were to test this idea in northern Sweden, where nitrogen (N) limitation of terrestrial plants is widespread, and where peat-forming, mire ecosystems are dominant features of the landscape. We quantified vertical patterns of N chemistry in a minerogenic mire, estimated the seasonal and annual hydrologic export of organic and inorganic N from this system, and evaluated the broader influence of mire cover on N chemistry across a stream network. Relatively high concentrations of ammonium (up to 2 mg l^?1) were observed in groundwater several meters below the peat surface, and N was routed to the outlet stream along deep, preferential flowpaths. Areal estimates of inorganic N export from the mire were several times greater than from an adjacent, forested catchment, with markedly higher loss rates during the growing season, when plant N demand is ostensibly greatest. At broader scales, mire cover was positively correlated with long-term concentrations of inorganic and organic N in streams across the drainage network. This study provides an example of how mire formation and peat accumulation can create broad-scale heterogeneity in nutrient supply and demand across boreal landscapes. This mismatch allows for hydrologic losses of reactive N that are independent of annual plant demand and potentially important to receiving lakes and streams.     

Change of peat mass during decomposition in mires of Poland and West Siberia

The paper presents the results of field experiment on peat decomposition in peat deposits of mires in West Siberia and Poland. Two principal factors determining the dynamics of peat mass are revealed: position in relief and contribution from the below ground organs of herbaceous plants. In a raised bog, an upland microlandscape, maximum values of peat mass loss were obtained in the upper layer of peat and minimum values in the lower layer. In all poor fen ecosystems which are lowland microlandscapes, similar values of peat mass losses at different depths were obtained. In mire ecosystems with a considerable proportion of grasses in the phytocenosis, the supply of peat in the upper half-meter layer is replenished by dead below ground organs of plants.     

Biotic and Abiotic Drivers of Peatland Growth and Microtopography: A Model Demonstration

Peatlands are important carbon reserves in terrestrial ecosystems. The microtopography of a peatland area has a strong influence on its carbon balance, determining carbon fluxes at a range of spatial scales. These patterned surfaces are very sensitive to changing climatic conditions. There are open research questions concerning the stability, behaviour and transformation of these microstructures, and the implications of these changes for the long-term accumulation of organic matter in peatlands. A simple two-dimensional peat microtopographical model was developed, which accounts for the effects of microtopographical variations and a dynamic water table on competitive interactions between peat-forming plants. In a case study of a subarctic mire in northern Sweden, we examined the consequences of such interactions on peat accumulation patterns and the transformation of microtopographical structure. The simulations demonstrate plausible interactions between peatland growth, water table position and microtopography, consistent with many observational studies, including an observed peat age profile from the study area. Our model also suggests that peatlands could exhibit alternative compositional and structural dynamics depending on the initial topographical and climatic conditions, and plant characteristics. Our model approach represents a step towards improved representation of peatland vegetation dynamics and net carbon balance in Earth system models, allowing their potentially important implications for regional and global carbon balances and biogeochemical and biophysical feedbacks to the atmosphere to be explored and quantified.     

Recognition of peat-forming plant communities from their peat deposits in two south Swedish bog complexes

Peat samples, 3 015 from 103 boring points, on two mires (Åkhult mire, Store Mosse mire) south Sweden, have been subjected to macrofossil analysis. Based on plant remains, 9 peat groups were distinguished in the field. A further classification using phytosociological methods revealed 29 peat types. The affinities between the peat types were determined from TABORD classification and a Reciprocal Averaging ordination. The primary floristic differentiation is correlated with a gradient from treeless-to wooded stands, which coincides largely with the mire expanse-mire margin gradient. The poor-rich gradient seems to parallel the treeless-wooded gradient as well and may reflect the natural conditions in this mire before it was affected by man. The hummock-mud-bottom gradient is easy to distinguish in peat, formed by bog communities, but is not distinct in peat formed by fen communities and impossible to detect in peat dominated by wood remains. The amount of identifiable remains depends on the decomposition, which is determined by (1) the period of time the plant litter stays in the acrotelm, and (2) the nutrient status. The decomposition is greatest in fen-peat with abundant wood remains. This probably depends on a good supply of oxygen caused by greater horizontal water movements and better nutrient status.     

An inventory of the mires of Hokkaido,Japan—their development,classification, decline,and conservation

Hokkaido Island is located in the cool temperate zone, and its climate conditions facilitated the formation of a variety of wetland types, the majority of them peat-forming mires. Most of these remained in a natural state until the early 20th century. However, drainage and subsequent conversion mostly to agricultural land have since destroyed more than 70% of the original wetland ecosystems. This paper (1) provides an overview of mire types, (2) reviews the development process of mires in Hokkaido during the Holocene, (3) analyzes the causes of losses of wetland areas, and (4) gives a summary of the current conservation and management status. Basic mire types that have been described in other parts of the northern hemisphere can also be recognized in Hokkaido, although there are floristic differences, and the frequency and intensity of volcanic impact and tsunamis is higher than in most other regions with abundant mire formation. Mire formation started at various points during the postglacial period; a few mountain mires in southwest Hokkaido date back to the Lateglacial, but most mountain mires formed during the mid to late Holocene. Most lowland mires developed at altitudes below 20 m and were influenced by the Jomon transgression that peaked ca. 6,000 years BP. The largest lowland mires started forming after the sea retreated, and many are not older than ca. 3,000 years. In 1996, the total number of wetlands (including peat-forming mires, freshwater marshes, and saltmarshes) greater than 1 ha was 150, with a total area of 59,881 ha. In 1928, when many wetlands were yet undeveloped, their total area was 200,642 ha. Most losses occurred between the 1950s and 1970s, when post-war development economics promoted agriculture and large-scale reclamation projects. Currently, 90.7% of mountain wetlands are public land, while 81.3% of the lowland wetlands are private or in mixed ownership. The ownership condition affects the possibilities for the protection of complete mire complexes especially in the lowlands. For effective conservation of wetland ecosystems it is necessary to include the catchment area in the planning of protected areas.     

A reappraisal of the mechanisms leading to ombrotrophy in British raised mires

Previous theories of raised mire initiation stress the role of autogenic processes aided by climatic forcing towards increased oceanicity. Recent evidence from stratigraphic surveys in Great Britain and Ireland, however, suggests that raised mire initiation can occur under conditions of falling or fluctuating water tables. Macrofossil assemblages from the lowermost raised peat strata can indicate repeated aeration of the newly formed peat surface. A previously unexplored mechanism for the fen-bog transition is discussed. New research is needed to assess its importance since a sound understanding of the way in which raised mires first formed is important for mire rehabilitation and conservation.     

Vegetation characteristics and eco-hydrological processes in a pristine mire in the Ob River valley (Western Siberia)

Relations between vegetation characteristics and eco-hydrological processes were assessed in a pristine mire in the valley of the Ob River (Western Siberia). Along a transect from the terrace scarp to the river, field data were collected on vegetation composition, peat stratigraphy, peat chemistry, hydrology and hydrochemistry. Based on floristic composition, eight vegetation communities were distinguished. Hydraulic head measurements were used to obtain an indication of groundwater flow directions. The water balance of the mire was calculated with a two-dimensional steady-state numerical groundwater model. Water types were defined based on cluster analysis of hydrochemical data. The results revealed that the dominant hydrological factor in the Ob mire is the discharge of groundwater, which supplies about threefold more water than net precipitation. Although the discharge flux decreases with increasing distance from the terrace scarp, high water levels and a “groundwater-like” mire water composition were observed in the major part of the study site. Precipitation and river water play only a minor role. Despite dilution of discharging groundwater with rainwater, spatial differences in pH and solute concentrations of the surficial mire water are small and not reflected in the vegetation composition. Although small amounts of silt and clay were found in the peat in the proximity of the river, indicating the occurrence of river floods in former times, no river-flood zone could be recognized based on hydrochemical characteristics or vegetation composition. A comparison of the Ob mire with well-studied and near-natural mires in the Biebrza River valley (Poland) revealed substantial differences in both vegetation characteristics and the intensity and spatial pattern of eco-hydrological processes. Differences in the origin and ratios of water fluxes as well as a dissimilar land use history would seem to be key factors explaining the differences observed.     

Geographical variation in Fennoscandian and Estonian Schoenus wetlands

Using TABORD five Schoenus ferrugineus associations have been distinguished from the literature. They are well distinguished by differential-species combinations and most of them are described earlier under identical names, e.g., the Primula-, Oxycoccus-, Myrica-, and Trichophorum-Schoenus ferrugineus ass. The Thalictrum-Schoenus ferrugineus ass. is a new syntaxon. They are further characterized by different floristic elements according to their geographical distribution. The Primula-Schoenus ferrugineus ass. is related to Central Europe, the Primulo-Schoenetum ferruginei from Oberd. (1957) 1962. All other associations discussed have no counterparts elsewhere in Europe. The shortcoming of this classification and the impossibility of a syntaxonomical ranking are emphasized. The variation in species composition and site conditions is elucidated by RA ordination. A complex soil moisture gradient is related to the differences in species composition between the Primula-, Oxycoccus-, and Myrica-Schoenus ferrugineus ass. Wet topogenous mire sites with peat formation and a rather low pH is typical of the Myrica-Schoenus ferrugineus ass., while the Primula-Schoenus ferrugineus ass. occurs either in moist soligenous mire sites or in to pogenous sites with strongly shifting water tables and with muck (Anmoor) instead of peat. The site conditions of the Oxycoccus-Schoenus ferrugineus ass. are most similar to those of the Myrica-Schoenus ferrugineus ass. The Trichophorum- and Thalictrum-Schoenus ferrugineus ass. occur on soligenous mire sites.     

Ecology of Racomitrium lanuginosum in British blanket mire - evidence from the palaeoecological record

Abstract

The moss Racomitrium lanuginosum (Hedw.) Brid. is widely distributed in the cool-oceanic north and west of the British Isles, where it is an important element in the vegetation of blanket mire. It has been described as occurring on the present-day surface of British blanket mire in two situations (i.e. where the local mire water table may be lowered, despite high atmospheric humidity), on the tops of tall hummocks and adjacent to areas of peat erosion, where it may be dominant in the vegetation. Accordingly, the occurrence of R. lanuginosum is widely perceived as indicative of drier mire conditions and/or mire degradation. In contrast, recent palaeoecological studies have documented the recurrence of R. lanuginosum in the absence of either hummock upgrowth or peat erosion. Such studies suggest that R. lanuginosum may also occur on blanket mire as a component of climatically-mediated mire development. This paper presents critical new data to document the decomposition of R. lanuginosum and describes the results of recent palaeoecological studies that have negated the exclusive role of R. lanuginosum in mire drying/degradation. We present evidence for the active role of R. lanuginosum in persistent blanket mire development, suggesting the moss may occur during periods of climate change towards increased wetness, after a sustained period of drier conditions. The results are of wider relevance in evidencing the sensitivity of oceanic blanket mire to past climate change.