水位与光强变化对尖叶泥炭藓孢蒴生产动态的影响

选取尖叶泥炭藓(Sphagnum capillifolium)为试验材料, 在模拟水位与光强条件下, 对人工构建的苔藓植物群落进行室内培养, 每隔1-3天观察并记录植株高度、孢蒴变化过程及变化时间, 分析了不同水位与光强条件对孢蒴生产的植物功能属性动态的影响。水位上升促进了蒴柄伸长及植株高增长, 增加了孢蒴开裂率及遮蔽率。光强增加有助于孢蒴生长, 并提高了孢蒴开裂率。在孢蒴直径以及植株高增长性状上, 水位与光强存在交互作用。水位与光强对孢蒴增长率均没有影响。此外, 水位升高与光强增加使孢蒴成熟及蒴柄伸长时间提前, 总体上使孢子释放时间分别提前了4.0 d和4.8 d, 由此可能减小了孢子体因受夏季干旱影响而败育的风险。孢子释放后, 繁殖株高增长加速, 可为未来的再次繁殖奠定基础。     

水位控制对农田泥炭藓产量的影响

为明确不同水位控制下农田土壤因子与泥炭藓产量之间的关系,解析影响泥炭藓产量的主要土壤因子,以贵州省龙里县水苔村种植年限相同的泥炭藓为研究对象,分析不同水位条件下泥炭藓生理生态指标与土壤因子的特征,并结合冗余分析,讨论水位和土壤因子的交互作用对泥炭藓生理生态指标的影响。结果表明：水苔村种植泥炭藓有1科1属5种,其中泥炭藓原亚种(Sphagnum palustre L. ssp.palustre)为优势种。泥炭藓生理生态指标均随水位升高逐渐上升,表明高水位有利于泥炭藓生长;土壤含水量(SWC, Soil Water Content)和孔隙度(STP, Soil Porosity)随水位升高逐渐增大,表明水位升高有助于增强土壤透水、透气及蓄水保墒能力;总氮(TN, Total Nitrogen)、总磷(TP, Total Phosphorus)、总钾(TK, Total Potassium)、有效磷(AP, Available Phosphorus)随水位升高逐渐降低,表明水位升高加速氮磷钾等营养元素淋失;脲酶(URE, Urease)和过氧化氢酶(CAT, Catalase)随水位升高逐渐...     

青藏高原泥炭地水位下降促进土壤碳积累的影响机制

酚类物质作为泥炭地重要的碳分解抑制剂,植被作为泥炭地关键的碳输入来源,它们在土壤碳(可溶性有机碳(DOC)等)周转过程中都发挥着重要作用。然而,目前关于植被群落结构、酚类物质以及DOC含量对水位波动的响应存在较大争议。因此,为明确泥炭地水位下降对植被群落结构、酚类物质以及DOC含量的影响并探明三者间的潜在联系,以若尔盖高原泥炭地作为研究对象,选取红原县日干乔地区3处不同地下水位泥炭地(水位由高到低依次为S1(-1.9 cm)、S2(-10 cm)、S3(-19 cm)样地),调查不同水位条件下植被群落结构特征,并探究酚类物质及土壤碳含量对水位波动的响应。结果表明:(1)从S1到S3样地水位下降促进土壤DOC显著增加(P<0.05),土壤总碳从S1到S2显著增加(P<0.05),而从S2到S3无显著差异;(2)泥炭地水位下降促使禾本科(发草Deschampsia cespitosa)、莎草科(木里薹草Carex muliensis、乌拉草Carex meyeriana)植物大量出现,植被群落高度显著增加(P<0.05)。植被群落地上生物量由153.67 g/m~2增加至...     

泥炭地特征性环境因子促进泥炭藓持久孢子库的形成

研究泥炭地特征性环境因子——淹水、少氧和化感物质对泥炭藓孢子持久性的影响, 可深入理解泥炭地泥炭藓持久孢子库的形成机制, 为退化泥炭地泥炭藓地被恢复研究提供参考。该研究以藓丘种和丘间种两种泥炭藓的孢子为试验材料, 通过室内模拟控制实验的方法, 研究泥炭藓孢子在空气、超纯水、泥炭地地表水和泥炭藓沥出液中, 及3种速率充气下, 孢子萌发力持久性的变化。经充气处理后, 泥炭藓孢子持久性显著低于不充气处理。不充气时, 泥炭藓孢子在含有化感物质的泥炭地地表水和泥炭藓沥出液中保存, 持久性显著高于在超纯水中保存。通径分析结果显示, 溶解氧是影响泥炭地泥炭藓孢子持久性的主要因子和限制因子, 养分元素氮(TN)和磷(TP)的浓度为孢子持久性的负作用因子。研究结果表明, 泥炭藓孢子散布于苔藓地被基质或淹水的丘间生境中, 比暴露于空气或在无化感物质的水中, 能更好地维持萌发力。泥炭地中, 泥炭藓孢子和其他植物的繁殖体的超长寿命可能归因于少氧、养分贫乏和丰富的化感物质等泥炭地特征性环境因子。     

若尔盖退化泥炭地土壤原核微生物群落结构对水位恢复的短期响应

退化泥炭地的恢复是目前受关注的重要环境问题。若尔盖退化泥炭地原核微生物群落结构对水位恢复的早期响应可以为其生态恢复提供理论依据。为探究原核微生物群落结构对水位恢复的短期响应, 该研究以若尔盖退化泥炭地为研究对象, 设置水位恢复(10和30 cm)和对照组(-10 cm), 进行了1年野外原位水位恢复试验。采集0-15 cm土壤样品, 测定土壤有机碳(SOC)、总氮(TN)、总磷(TP)含量和pH等化学性质, 采用16S rRNA基因高通量测序技术分析微生物群落结构。结果表明: 水位恢复一定程度上能提高SOC、TN、TP含量及其化学计量比, 但与对照组差异不显著。主要优势微生物在门水平为酸杆菌(Acidobacteria)、变形菌(Proteobacteria)和疣微菌(Verrucomicrobia)。短期水位恢复(10和30 cm)对土壤原核微生物的α多样性没有显著影响, 而只是显著降低疣微菌和Spartobacteria的相对丰度, 增加了产甲烷菌种类。疣微菌和Spartobacteria相对丰度与水位和土壤pH呈显著负相关关系。退化泥炭地水位恢复过程中原核微生物群落结构对C:P、N:P和SOC含量响应较为敏感。综上, 短期水位恢复没有改变原核微生物α多样性, 而主要降低了疣微菌和Spartobacteria的相对丰度, 增加了产甲烷菌种类, 这将可能导致甲烷产生途径发生变化。土壤C:P、N:P和SOC含量控制了退化泥炭地随短期水位恢复过程中原核微生物群落结构变异。该研究在一定程度上丰富了原核微生物群落结构对短期水位响应的认识。     

长白山哈泥泥炭地丘间生境泥炭藓孢子的寿命

长寿有性繁殖体对于植物种群的长存具有重要意义,迄今,泥炭地苔藓植物孢子长寿性研究还很少。在长白山哈泥泥炭地钻取丘间表层泥炭样品,测定泥炭腐殖化度和烧失量,逐层提取和培养泥炭藓孢子,研究埋藏时间对孢子萌发的影响。结果表明,丘间泥炭藓孢子埋藏环境中,随着埋深的增加即埋藏年限的增加,泥炭腐殖化度和烧失量总体上分别呈现增加和递减的趋势,而地层泥炭藓孢子萌发率呈现直线递减的规律,但在埋藏近150余年后孢子萌发率仍可达40%。研究进一步证明泥炭藓具有长期持久孢子库,根据推算,泥炭地丘间埋藏环境中,泥炭藓孢子最大寿命可超过400a。     

水文管理措施对长白山区恢复泥炭地土壤酶活性的影响

以长白山区天然泥炭地、不同水文管理的恢复泥炭地(高水位、高-低水位循环和低水位)及退化泥炭地(弃耕地)为研究对象,分析水文管理措施对恢复泥炭地表层土壤(0～10 cm)酶活性的影响及其驱动因素。结果表明：泥炭地土壤β-1,4-葡萄糖苷酶和β-1,4-N-乙酰葡糖氨糖苷酶活性表现为天然泥炭地>恢复泥炭地>退化泥炭地;退化泥炭地土壤酸性磷酸酶活性显著低于天然泥炭地和恢复泥炭地;多酚氧化酶活性在天然泥炭地最低。在恢复泥炭地,随着恢复区管理水位的下降,土壤β-1,4-葡萄糖苷酶、β-1,4-N-乙酰葡糖氨糖苷酶和酸性磷酸酶活性均逐渐降低,土壤多酚氧化酶活性表现为高-低水位循环恢复区最低。相关分析表明,土壤β-1,4-葡萄糖苷酶活性和β-1,4-N-乙酰葡糖氨糖苷酶活性均与土壤有机碳、含水量、水位和全氮含量呈显著正相关,与pH和全磷含量呈显著负相关;土壤酸性磷酸酶活性与水位呈显著正相关,与pH和全磷含量呈显著负相关;土壤多酚氧化酶活性与土壤有机碳、含水量和全氮含量呈显著负相关。RDA分析表明,环境因子共可解释研究区土壤酶活性变异的81.2%,水位和土壤有机碳是影响研究区土壤酶活性的主...     

养分浓度和光照强度对泥炭藓有性更新的影响

作为优势植物, 泥炭藓(Sphagnum)在泥炭沼泽中缺乏有性更新的原因尚不清楚。针对影响孢子萌发的光强和养分条件, 以泥炭藓(S. palustre)为材料, 通过室内孢子萌发实验, 研究不同光强和养分浓度对孢子萌发率、萌发势及萌发指数的影响。4 种培养基中, 养分浓度高的营养液培养基中孢子萌发率最高, 达到60%, 其次为养分浓度与营养液相近的琼脂+营养液培养基, 萌发率为48%, 再次为养分水平很低的沼泽水培养基, 萌发率约为30%, 几乎无养分的蒸馏水培养基中萌发率最低, 约为5%。萌发势和萌发指数亦呈现相同的规律。琼脂+营养液和营养液培养基较沼泽水和蒸馏水培养基孢子萌发时间提前约3 天时间。增加光强使孢子萌发率仅提高10%。研究表明, 低养分浓度和弱光照均不利于孢子萌发, 相对而言, 泥炭沼泽的贫营养特征应是限制泥炭藓有性更新的更重要因素。     

红壤侵蚀裸地植被恢复及土壤有机碳对团聚体稳定性的影响

植被恢复后土壤有机质提高 ,可能提高土壤团聚体稳定性 ,从而增强土壤抗蚀性 ,防止土壤退化。研究目的 :(1 )模拟自然条件下土壤团聚体破碎机制 ,研究不同恢复植被下团聚体稳定性的变化 ;(2 )确定不同恢复植被下土壤有机碳的积累与团聚体稳定性的关系 ,以期理解侵蚀裸地植被恢复过程及土壤有机碳对土壤结构性质的贡献。供试土壤采为侵蚀裸地、恢复 1 4 a的胡枝子和樟树林地、30～ 40 a树龄的稀疏马尾松林地以及菜园地等 5种土地利用方式。研究结果表明快速湿润是团聚体破碎的主要机制 ,其团聚体稳定性 (NMWD)次序为 :快速湿润 <湿润震荡 <慢速湿润。不同恢复植被对团聚体稳定性影响也表现不同 ,在快速湿润中 ,马尾松 >菜园地 >胡枝子 >樟树、裸地。湿润震荡处理后 ,其稳定性顺序是 :菜园地、马尾松 >裸地 >樟树 >胡枝子。而在慢速湿润中不同植被影响不明显。小团聚体的稳定性显著高于大团聚体的稳定性。快速湿润和湿润震荡下土壤团聚体稳定性与有机碳含量呈显著正相关 (r=0 .82 **,r=0 .66*) ,但慢速湿润下其相关性很低 (r=0 .2 2 )。结果还表明与活性 Al2 O3 相比 ,活性 Fe2 O3 对团聚体稳定性作用更显著。土壤团聚体湿润破碎后 ,有机碳含量和 C/N比随着破碎团聚体粒级的增大而提高。研究结果说明植被     

泥炭藓: 一类具有重要生态、经济和科学价值的碳封存植物

全球气候变暖是人类面临最严峻的环境挑战。有效控制碳排放, 充分发挥生态系统的固碳能力是实现碳中和目标的重要手段。作为碳封存能力最强的一种湿地类型, 泥炭地是加快实现碳中和目标的关键陆地生态系统。作为泥炭地“有效的生态系统工程师”, 泥炭藓(Sphagnum)在泥炭地的碳汇功能、过滤淡水及保护土地免受洪水侵袭等方面具有极其重要的作用。100多年来, 泥炭藓广泛应用于医药保健、污染监测和废水处理等领域, 尤其是作为一类最值得信赖的土壤介质和保湿材料一直被广泛用于园艺产业。在全球气候变暖和“双碳”目标的大背景下, 泥炭藓已经成为生命科学和生态学研究的热点。该文主要从泥炭藓的形态、物种多样性和起源、生境与分布、繁殖和保护、培养与种植、环境指示和监测、用途和应用, 以及碳封存、储水和酸化能力等方面进行综述, 旨在为泥炭藓研究、泥炭地的保护和恢复以及泥炭藓开发利用和产业发展提供借鉴与参考。     

Effects of microtopography and water table on Sphagnum palustre L. in subtropical high mountains and implications for peatland restoration

Introduction. Human disturbance has recently led to increasingly serious destruction of Sphagnum L. wetlands in subtropical high mountains, resulting in an urgent need for wetland restoration.

Methods. Through a field experiment conducted in western Hubei Province, China, the effects of four different microtopographic types [concave surface, convex surface, concave and convex surface (CC surface), and flat surface] and water table depth (0 to ?30?cm) on three growth indicators (number of capitula, coverage and biomass) of Sphagnum palustre L. were examined. The objective was to identify the optimal hydrological conditions for S. palustre growth and thus facilitate its rapid recolonisation and restoration of these wetlands.

Key results. The results showed that different microtopographic conditions significantly influenced S. palustre growth. Among them, S. palustre in the CC surface showed the worst growth, while no significant differences existed among the other three microtopographic types. Additionally, as the water table increased, the growth of S. palustre increased, but long-term flooding impeded growth. The water table affected S. palustre growth via effects on its tissue water content.

Conclusions. Microtopographic reshaping was not essential for the success of S. palustre recolonisation, and microtopography that maintained the water table to within ?10?cm of the surface without flooding were best, independent of the microtopographic types. In addition, the growth patterns of S. palustre changed with changes in the environment, which may be related to its long-term adaptation to conditions of a lower water table.     

Effects of water level and light intensity on capsule production dynamics of Sphagnum capillifolium

 选取尖叶泥炭藓(Sphagnum capillifolium)为试验材料, 在模拟水位与光强条件下, 对人工构建的苔藓植物群落进行室内培养, 每隔1-3天观察并记录植株高度、孢蒴变化过程及变化时间, 分析了不同水位与光强条件对孢蒴生产的植物功能属性动态的影响。水位上升促进了蒴柄伸长及植株高增长, 增加了孢蒴开裂率及遮蔽率。光强增加有助于孢蒴生长, 并提高了孢蒴开裂率。在孢蒴直径以及植株高增长性状上, 水位与光强存在交互作用。水位与光强对孢蒴增长率均没有影响。此外, 水位升高与光强增加使孢蒴成熟及蒴柄伸长时间提前, 总体上使孢子释放时间分别提前了4.0 d和4.8 d, 由此可能减小了孢子体因受夏季干旱影响而败育的风险。孢子释放后, 繁殖株高增长加速, 可为未来的再次繁殖奠定基础。     

Comparison of Vegetation and CO2 Dynamics Between a Restored Cut‐Away Peatland and a Pristine Fen: Evaluation of the Restoration Success

We studied the restoration success of a cut‐away peatland 10 years after restoration by comparing the vegetation and CO₂ dynamics with those of a pristine peatland of similar nutrition level and climate. Vegetation and CO₂ dynamics were monitored during one growing season. We used DCA (detrended correspondence analysis) and diversity indices to study the vegetation composition within and between the sites, and non‐linear regression models to estimate the seasonal CO₂ fluxes and balances of the sites. Based on both DCA and diversity indices, the study plots in the restored site differed more in the vegetation composition than the study plots in the pristine site. The variation in the CO₂ fluxes and balance was greater in the restored than in the pristine site, resulting from the heterogeneous vegetation in the restored site. The seasonal net CO₂ balance was positive (sink) at both sites, the restored site binding on average 500 ± 410 g CO₂/m² and the pristine site 390 ± 265 g CO₂/m² (statistically not different, p = 0.575). The results indicate that the restoration of the vegetation composition is still incomplete but the vegetation coverage is sufficient for the restored site to function as a sink of atmospheric CO₂.     

Sensitivity of C Sequestration in Reintroduced Sphagnum to Water-Level Variation in a Cutaway Peatland

The reintroduction of Sphagnum fragments has been found to be a promising method for restoring mire vegetation in a cutaway peatland. Although it is known that moisture controls Sphagnum photosynthesis, information concerning the sensitivity of carbon dynamics on water‐level variation is still scarce. In a 4‐year field experiment, we studied the carbon dynamics of reintroduced Sphagnum angustifolium material in a restored (rewetted) cutaway peatland. Cutaway peatland restored by Sphagnum reintroduction showed high sensitivity to variation in water level. Water level controlled both photosynthesis and respiration. Gross photosynthesis (P_G) had a unimodal response to water‐level variation with optimum level at ?12 cm. The range of water level for high P_G (above 60% of the maximum light‐saturated P_G) was between 22 and 1 cm below soil surface. Water level had a dual effect on total respiration. When the water level was below soil surface, peat respiration increased rapidly along the lowering water level until the respiration rate started to slow down at approximately ?30 cm. Contrary to peat respiration, the response of Sphagnum respiration to water‐level variation resembled that of photosynthesis with an optimum at ?12 cm. In optimal conditions, Sphagnum reintroduction turned the cutaway site from carbon source to a sink of 23 g C/m² per season (mid‐May to the end of September). In dry conditions, lowered photosynthesis together with the higher peat respiration led to a net loss of 56 g C/m². Although the water level above the optimum amplitude restricted CO₂ fixation, a decrease in peat respiration led to a positive CO₂ balance of 9 g C/m².     

Patterns in Vegetation and CO<Subscript>2</Subscript> Dynamics along a Water Level Gradient in a Lowland Blanket Bog

The surface of bogs is commonly patterned and composed of different vegetation communities, defined by water level. Carbon dioxide (CO₂) dynamics vary spatially between the vegetation communities. An understanding of the controls on the spatial variation of CO₂ dynamics is required to assess the role of bogs in the global carbon cycle. The water level gradient in a blanket bog was described and the CO₂ exchange along the gradient investigated using chamber based measurements in combination with regression modelling. The aim was to investigate the controls on gross photosynthesis (P_G), ecosystem respiration (R_E) and net ecosystem CO₂ exchange (NEE) as well as the spatial and temporal variation in these fluxes. Vegetation structure was strongly controlled by water level. The species with distinctive water level optima were separated into the opposite ends of the gradient in canonical correspondence analysis. The number of species and leaf area were highest in the intermediate water level range and these communities had the highest P_G. Photosynthesis was highest when the water level was 11 cm below the surface. Ecosystem respiration, which includes decomposition, was less dependent on vegetation structure and followed the water level gradient more directly. The annual NEE varied from −115 to 768 g CO₂ m⁻², being lowest in wet and highest in dry vegetation communities. The temporal variation was most pronounced in P_G, which decreased substantially during winter, when photosynthetic photon flux density and leaf area were lowest. Ecosystem respiration, which is dependent on temperature, was less variable and wintertime R_E fluxes constituted approximately 24% of the annual flux.     

Restoration of Sphagnum and restiad peatlands in Australia and New Zealand reveals similar approaches

Peatlands in Australia and New Zealand are composed mainly of Restionaceous and Cyperaceous peats, although Sphagnum peat is common in wetter climates (Mean Annual Precipitation > 1,000 mm) and at higher altitudes (>1,000 m). Experimental trials in two contrasting peatland types—fire‐damaged Sphagnum peatlands in the Australian Alps and cutover restiad bogs in lowland New Zealand—revealed similar approaches to peatland restoration. Hydrological restoration and rehydration of drying peats involved blocking drainage ditches to raise water tables or, additionally in burnt Sphagnum peatlands, peat‐trenching, and the use of sterilized straw bales to form semipermanent “dam walls” and barriers to spread and slow surface water movement. Recovery to the predisturbance vegetation community was most successful once protective microclimates had been established, either artificially or naturally. Specifically, horizontally laid shadecloth resulted in Sphagnum cristatum regeneration rates and biomass production 3–4 times that of unshaded vegetation (Australia), and early successional nurse shrubs facilitated establishment of Sporadanthus ferrugineus (New Zealand) within 2–3 years. On severely burnt or cutover sites, a patch dynamic approach using transplants of Sphagnum or creation of restiad peat “islands” markedly improved vegetation recovery. In New Zealand, this approach has been scaled up to whole mine‐site restoration, in which the newly vegetated islands provide habitat and seed sources for plants and invertebrates to spread onto surrounding areas. Although a vegetation cover can be established relatively rapidly in both peatland types, restoration of invertebrate communities, ecosystem processes, and peat hydrological function and accumulation may take many decades.     

Restoration Potential of Sedge Meadows in Hand‐Cultivated Soybean Fields in Northeastern China

Sedge meadows can be difficult to restore from farmed fields if key structural dominants are missing from propagule banks. In hand‐cultivated soybean fields in northeastern China, we asked if tussock‐forming Carex and other wetland species were present as seed or asexual propagules. In the Sanjiang Plain, China, we compared the seed banks, vegetative propagules (below‐ground) and standing vegetation of natural and restored sedge meadows, and hand‐cultivated soybean fields in drained and flooded conditions. We found that important wetland species survived cultivation as seeds for some time (e.g. Calamogrostis angustifolia and Potamogeton crispus) and as field weeds (e.g. C. angustifolia and Phragmites australis). Key structural species were missing in these fields, for example, Carex meyeriana. We also observed that sedge meadows restored without planting or seeding lacked tussock‐forming sedges. The structure of the seed bank was related to experimental water regime, and field environments of tussock height, thatch depth, and presence of burning as based on Nonmetric Multidimensional Scaling analysis. To re‐establish the structure imposed by tussock sedges, specific technologies might be developed to encourage the development of tussocks in restored sedge meadows.     

Vegetation Restoration and Its Effects on Carbon Balance in Guangdong Province, China

The significance of the regional carbon (C) balance of vegetation restoration to global change was studied in Guangdong Province, one of the most populated provinces in China. The percentage of the province in forestland cover increased steadily from 26.23% in 1979 to 50.11% in 1998 owing to restoration of forests. During this period, the area increase in the conifer forest was 424.83 × 10⁴ ha, whereas the area in broad-leaved, mixed, and other forests increased by 68.82 × 10⁴, 18.94 × 10⁴, and 60.46 × 10⁴ ha, respectively. C sequestration by forest soils from 1979 to 1998 was 389.36 Mt, equivalent to 1.43 Pg fixed carbon dioxide (CO₂). The total annual CO₂ sequestration by forests and the soils was 118.05 Mt, which was about half of the annual CO₂ emission in Guangdong. The role of forest management and restoration in improving the carbon balance is discussed.