模拟气候变化对３种草原植物群落混合凋落物分解的影响

 应用海拔引起的自然温度梯度作为气候变化研究的替代系统,结合网袋法,目的在于评价气候变化对草甸草原、羊草(Leymus chinensis )草原和大针茅(Stipa grandis)草原混合凋落物分解过程的可能影响。结果表明：较之当前气候,在气温升高2.7℃,降水基本保持不变的气候变化情景下,3种凋落物的分解速率分别提高了15.38％、35.83％和6.68％;而在温度升高2.2℃或更高,降水降低20％或更高的气候变化情景下,各种凋落物的分解速率将降低。此外,各种凋落物的分解动态对所模拟的气候变化情景的响应不同,但没有发现凋落物分解速率与凋落物本身C、N、C／N间的密切关系。     

Litter stoichiometric traits of plant species of high-latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition

? High-latitude ecosystems are important carbon accumulators, mainly as a result of low decomposition rates of litter and soil organic matter. We investigated whether global change impacts on litter decomposition rates are constrained by litter stoichiometry. ? Thereto, we investigated the interspecific natural variation in litter stoichiometric traits (LSTs) in high-latitude ecosystems, and compared it with climate change-induced LST variation measured in the Meeting of Litters (MOL) experiment. This experiment includes leaf litters originating from 33 circumpolar and high-altitude global change experiments. Two-year decomposition rates of litters from these experiments were measured earlier in two common litter beds in sub-Arctic Sweden. ? Response ratios of LSTs in plants of high-latitude ecosystems in the global change treatments showed a three-fold variation, and this was in the same range as the natural variation among species. However, response ratios of decomposition were about an order of magnitude lower than those of litter carbon/nitrogen ratios. ? This implies that litter stoichiometry does not constrain the response of plant litter decomposition to global change. We suggest that responsiveness is rather constrained by the less responsive traits of the Plant Economics Spectrum of litter decomposability, such as lignin and dry matter content and specific leaf area.     

全球气候变暖对凋落物分解的影响

凋落物分解作为生态系统核心过程,参与生态系统碳的周转与循环,影响生态系统碳的收支平衡,调控生态系统对全球气候变暖的反馈结果。全球气候变暖通过环境因素、凋落物数量和质量以及分解者3个方面,直接或间接地作用于凋落物分解过程,并进一步影响土壤养分周转和碳库动态。气候变暖可通过升高温度和改变实际蒸散量等环境因素直接作用于凋落物分解。气候变暖可引起植物物种短期内碳、氮和木质素等化学性质的改变以及群落中物种组成的长期变化从而改变凋落物质量。在凋落物分解过程中,土壤分解者亚系统作为主要生命组分(土壤动物和微生物)彼此相互作用、相互协调共同参与调节凋落物的分解过程。凋落物分解可以通过改变土壤微生物量、微生物活动和群落结构来加快微生物养分的固定或矿化,以形成新的养分利用模式来改变土壤有机质从而对气候变化做出响应。未来凋落物分解的研究方向应基于大尺度跨区域分解实验和长期实验,关注多个因子交互影响下,分解过程中碳、氮养分释放、地上/地下凋落物分解生物学过程与联系、分解者亚系统营养级联效应等方面。     

放牧对青藏高原东部两种典型高寒草地类型凋落物分解的影响

为认识放牧对青藏高原东部中生性的高寒草甸草地和半湿生的沼泽草地凋落物分解的影响,在这两种草地上分别设置了围栏和放牧样地,研究了其各自的混合凋落物样品和4个优势物种(发草Deschampsiacaespitos、鹅绒委陵菜Potentilla anserine、木里苔草Carexmuliensis、藏嵩草Kobresiatibetica)凋落物的分解和养分释放动态,这4个优势物种也大致代表了当地沼泽草地生态系统在放牧和气候变暖驱动下逆行演替不同阶段的优势物种类群。结果表明,各优势物种凋落物的分解速率有显著差异;放牧在总体上促进了凋落物的分解,但不同物种的响应有所不同;放牧对凋落物C的释放影响不显著或有抑制作用,但对N、P的释放具有一定促进作用。对各优势物种凋落物分解和养分释放模式的分析表明,群落逆行演替过程中,凋落物分解和C释放加速,可能促进沼泽湿地退化的正反馈效应。草甸草地的退化标志物种鹅绒委陵菜具有较高的凋落物质量和分解速度,反映了中生条件下植物应对牲畜啃食采用"逃避"而非"抵抗"策略的趋向。     

Controls on long-term root and leaf litter decomposition in neotropical forests

Litter decomposition represents one of the largest annual fluxes of carbon (C) from terrestrial ecosystems, particularly for tropical forests, which are generally characterized by high net primary productivity and litter turnover. We used data from the Long-Term Intersite Decomposition Experiment (LIDET) to (1) determine the relative importance of climate and litter quality as predictors of decomposition rates, (2) compare patterns in root and leaf litter decomposition, (3) identify controls on net nitrogen (N) release during decay, and (4) compare LIDET rates with native species studies across five bioclimatically diverse neotropical forests. Leaf and root litter decomposed fastest in the lower montane rain and moist forests and slowest in the seasonally dry forest. The single best predictor of leaf litter decomposition was the climate decomposition index (CDI), explaining 51% of the variability across all sites. The strongest models for predicting leaf decomposition combined climate and litter chemistry, and included CDI and lignin ( R ²=0.69), or CDI, N and nonpolar extractives ( R ²=0.69). While we found no significant differences in decomposition rates between leaf and root litter, drivers of decomposition differed for the two tissue types. Initial stages of decomposition, determined as the time to 50% mass remaining, were driven primarily by precipitation for leaf litter ( R ²=0.93) and by temperature for root litter ( R ²=0.86). The rate of N release from leaf litter was positively correlated with initial N concentrations; net N immobilization increased with decreasing initial N concentrations. This study demonstrates that decomposition is sensitive to climate within and across tropical forests. Our results suggest that climate change and increasing N deposition in tropical forests are likely to result in significant changes to decomposition rates in this biome.     

Climate and litter quality differently modulate the effects of soil fauna on litter decomposition across biomes

Climate and litter quality have been identified as major drivers of litter decomposition at large spatial scales. However, the role played by soil fauna remains largely unknown, despite its importance for litter fragmentation and microbial activity. We synthesised litterbag studies to quantify the effect sizes of soil fauna on litter decomposition rates at the global and biome scales, and to assess how climate, litter quality and soil fauna interact to determine such rates. Soil fauna consistently enhanced litter decomposition at both global and biome scales (average increment ~ 27%). However, climate and litter quality differently modulated the effects of soil fauna on decomposition rates between biomes, from climate‐driven biomes to those where climate effects were mediated by changes in litter quality. Our results advocate for the inclusion of biome‐specific soil fauna effects on litter decomposition as a mean to reduce the unexplained variation in large‐scale decomposition models.     

Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes

Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide. Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.     

Litter decomposition: what controls it and how can we alter it to sequester more carbon in forest soils?

Key recent developments in litter decomposition research are reviewed. Long-term inter-site experiments indicate that temperature and moisture influence early rates of litter decomposition primarily by determining the plants present, suggesting that climate change effects will be small unless they alter the plant forms present. Thresholds may exist at which single factors control decay rate. Litter decomposes faster where the litter type naturally occurs. Elevated CO₂ concentrations have little effect on litter decomposition rates. Plant tissues are not decay-resistant; it is microbial and biochemical transformations of materials into novel recalcitrant compounds rather than selective preservation of recalcitrant compounds that creates stable organic matter. Altering single characteristics of litter will not substantially alter decomposition rates. Nitrogen addition frequently leads to greater stabilization into humus through a combination of chemical reactions and enzyme inhibition. To sequester more C in soil, we need to consider not how to slow decomposition, but rather how to divert more litter into humus through microbial and chemical reactions rather than allowing it to decompose. The optimal strategy is to have litter transformed into humic substances and then chemically or physically protected in mineral soil. Adding N through fertilization and N-fixing plants is a feasible means of stimulating humification.     

Genotypic trait variation modifies effects of climate warming and nitrogen deposition on litter mass loss and microbial respiration

Intraspecific variation in genotypically determined traits can influence ecosystem processes. Therefore, the impact of climate change on ecosystems may depend, in part, on the distribution of plant genotypes. Here we experimentally assess effects of climate warming and excess nitrogen supply on litter decomposition using 12 genotypes of a cosmopolitan foundation species collected across a 2100 km latitudinal gradient and grown in a common garden. Genotypically determined litter‐chemistry traits varied substantially within and among geographic regions, which strongly affected decomposition and the magnitude of warming effects, as warming accelerated litter mass loss of high‐nutrient, but not low‐nutrient, genotypes. Although increased nitrogen supply alone had no effect on decomposition, it strongly accelerated litter mass loss of all genotypes when combined with warming. Rates of microbial respiration associated with the leaf litter showed nearly identical responses as litter mass loss. These results highlight the importance of interactive effects of environmental factors and suggest that loss or gain of genetic variation associated with key phenotypic traits can buffer, or exacerbate, the impact of global change on ecosystem process rates in the future.     

Regional patterns and controls of leaf decomposition in Australian tropical rainforests

Future climates have the potential to alter decomposition rates in tropical forest with implications for carbon emissions, nutrient cycling and retention of standing litter. However, our ability to predict impacts, particularly for seasonally wet forests in the old world, is limited by a paucity of data, a limited understanding of the relative importance of different aspects of climate and the extent to which decomposition rates are constrained by factors other than climate (e.g. soil, vegetation composition). We used the litterbag method to determine leaf litter decay rates at 18 sites distributed throughout the Australian wet tropics bioregion over a 14‐month period. Specifically, we investigated regional controls on litter decay including climate, soil and litter chemical quality. We used both in situ litter collected from litterfall on site and a standardized control leaf litter substrate. The control litter removed the effect of litter chemical quality and the in situ study quantified decomposition specific to the site. Decomposition was generally slower than for other tropical rainforests globally except in our wet and nutrient‐richer sites. This is most likely attributable to the higher latitude, often highly seasonal rainfall and very poor soils in our system. Decomposition rates were best explained by a combination of climate, soil and litter quality. For in situ litter (native to the site) this included: average leaf wetness in the dry season (LWDS; i.e. moisture condensation) and the initial P content of the leaves, or LWDS and initial C. For control litter (no litter quality effect) this included: rainfall seasonality (% dry season days with 0‐mm rainfall), soil P and mean annual temperature. These results suggest that the impact of climate change on decomposition rates within Australian tropical rainforests will be critically dependent on the trajectory of dry season moisture inputs over the coming decades.     

Effects of environmental warming and drought on size‐structured soil food webs

Soil systems maintain important ecosystem processes crucial for plant life and food production. Especially agricultural systems are strongly affected by climate change due to low vegetation cover associated with high temperatures and drought. Nevertheless, the response of soil systems to climate change is little explored. We used microcosms with a simplified soil community to address effects of climate change using independent temperature and dryness gradients and addressed their effects on top–down control and litter decomposition. The community consisted of maize litter as a basal resource, fungi, springtails and as top predators mites and centipedes. As the body‐size structure is of high importance for communities, we included differently‐sized springtails and predator species. After seven weeks, the experiment was terminated, and the impact of climate change on direct feeding interactions and indirect effects across trophic levels was analysed. With increasing temperature and dryness, consumption rates increased, thereby amplifying the negative influence of consumer populations on their resources. Hence, these climate‐change variables increased the top–down control of 1) predators (mainly mites) on springtails and 2) fungi on litter decomposition. In addition, we found that the climate‐change variables strengthened trophic cascades from predators on fungi whose density was thus increasingly decoupled from top–down control by their springtail consumers. Their increased decomposition rates are of high importance for carbon cycling and may result in accelerated nutrient turnover. In conclusion, our results suggest that climate change may strongly influence the structure and functioning of soil systems by strengthening consumption rates and trophic cascades, which will have far reaching consequences for the nutrient turnover and productivity of agricultural ecosystems.     

Litter quality in a north European transect versus carbon storage potential

Newly shed foliar plant litter often has a decomposition rate of ca 0.1–0.2% day^–1, which decreases greatly with time and may reach 0.0001 to 0.00001% day^–1 or lower in litter material in the last stages of decay. The decrease in decomposability (substrate quality) varies among species and is complex, involving both direct chemical changes in the substrate itself and the succession in microorganisms able to compete for substrate with a given chemical composition. In late stages, the decomposition appears very little affected by climate, suggesting that climate change will have little effect on late-stages decomposition rates. Here, we apply a model for the late stages of litter decomposition to address the question of climate-change effects on soil-C storage. Decomposition of litter turning into soil organic matter (SOM) is determined by the degradation rate of lignin. In the last phases of decay, raised N concentrations have a rate-retarding effect on lignin degradation and thus on the decomposition of far-decomposed litter and litter in near-humus stages. The retardation of the decomposition rate in late stages may be so strong that decomposition reaches a limit value at which total mass losses virtually stop. At such a stage the remaining litter would be close to that of stabilized SOM. The estimated limit values for different species range from about 45 to 100% decomposition indicating that between 0 and 55% should either be stabilized or decompose extremely slowly. For no less than 106 long-term studies on litter decomposition, encompassing 21 litter types, limit values were significantly and negatively related to N concentration, meaning that the higher the N concentration in the newly shed litter (the lower the C/N ratio) the more litter was left when it reached its limit value. Trees growing under warmer and wetter climates (higher actual evapotranspiration, AET) tend to shed foliar litter more rich in N than those growing under colder and drier climates. A change in climate resulting in higher AET would thus mean that within species, e.g., Scots pine, a higher N level in the foliar litter may result. Further, within the boreal system deciduous species appear to have foliar litter richer in N than have conifers and within the conifers group, Norway spruce has needle litter more rich in N than, e.g., Scots pine. Thus, a change of species (e.g., by planting) from pine to spruce or from spruce to a deciduous species such as birch may result in a higher N level in the litter fall at a given site. In both cases the result would be a lower limit value for decomposition. The paper presents an hypothesis, largely based on available data that a change in climate of 4° higher annual average temperature and 40% higher precipitation in the Baltic basin would result in higher N levels in litter, lower decomposition and thus a considerable increase in humus accumulation.     

地上枯落物的累积、分解及其在陆地生态系统中的作用

了解陆地生态系统地上枯落物的累积和分解过程对认识它的生态作用、通过管理地上枯落物调控陆地生态系统功能和服务有重要意义。综述了陆地生态系统地上枯落物的积累和分解过程及其影响因素,然后概括了通过这些过程地上枯落物所发挥的生态作用,最后,在全球变化背景下,基于当前研究进展提出陆地生态系统地上枯落物研究的前景。地上枯落物累积在时间尺度上一般遵循植物的生命周期,同时也受环境因子的调控。大的空间尺度上,枯落物累积主要受水热因子控制,伴随植被类型的变化,表现随纬度升高而减少的趋势。然而,在局域尺度内,枯落物累积除受水、热因子限制,还被群落结构、土壤条件、植食动物等因素影响,表现较大变异性。当前,人类干扰作为一个不可忽视的因素,正在强烈甚至不可逆转的改变地表植被覆盖和枯落物累积。地上枯落物的分解过程包括淋溶、光降解、土壤动物和微生物分解,这些过程同时进行并相互影响。尽管目前还不清楚,但区分这些分解过程和分解产物的去向对了解陆地生态系统物质循环有重要意义。枯落物分解首先被自身类型、化学组成、物种多样性决定,同时也受分解者群体、非生物环境影响。其中,枯落物分解与其化学特性、物种多样性及土壤养分状况的关系是研究的热点,也是广泛争议的焦点。通过累积和分解,地上枯落物对陆地生态系统有物理、化学、生物作用。目前,枯落物的物理和化学作用研究较为透彻,而由于受枯落物数量、环境条件、响应植物特征或一些有待挖掘的未知因素的共同限制,地上枯落物的生物作用,尤其对植物的作用在不同研究中仍没有达成普遍的共识。全球变化可能影响地上枯落物累积、分解和生态作用。在全球变化的背景,研究地上枯落物产量和性状变化、阐明枯落物分解的分室模型、继续分析枯落物性状和分解关系、深入揭示枯落物的生态作用及其制约因素,理解和预测地上枯落物数量和质量变化对陆地生态系统功能和服务的影响是必要的。     

湿地枯落物分解及其对全球变化的响应

综述了当前湿地枯落物分解及其对全球变化响应的研究动态。湿地枯落物分解研究已随研究方法的改进而不断深化;当前湿地枯落物分解过程研究主要集中在有机质组分和元素含量变化特征的探讨上;湿地枯落物分解同时受生物因素（即枯落物性质以及参与分解的异养微生物和土壤动物的种类、数量和活性等）和非生物因素（即枯落物分解过程的外部环境条件,包括气候条件、水分条件、酸碱度与盐分条件以及湿地沉积的行为与特征等）的制约;模型已成为湿地枯落物分解研究的重要手段,对其研究也在不断深化。还讨论了湿地枯落物分解对于全球变化的响应,指出全球变暖、大气CO2浓度上升、干湿沉降及其化学组成改变可能对枯落物分解产生的直接、间接和综合影响。最后,指出了当前该领域研究尚存在的问题以及今后亟需加强的几个研究方面。     

森林凋落物分解及其对全球气候变化的响应

凋落物分解是重要的森林生态系统过程之一,受到气候、凋落物质量、土壤生物群落等生物和非生物因素的综合调控．迄今,有关不同森林生态系统和不同树种地上部分的凋落物动态、凋落物分解过程中的养分释放动态、生物和非生物因素对凋落物分解的影响等研究报道较多,但对地下凋落物的分解研究相对较少．近年来,森林凋落物分解对以大气CO2浓度增加和温度升高为主要特征的全球变化的响应逐步受到重视,但其研究结果仍具有很多不确定性．因此,未来凋落物生态研究的重点应是凋落物分解对土壤有机碳固定的贡献、地上／地下凋落物的物理、化学和生物学过程及其对各种生态因子（例如冻融、干湿交替）及交互作用的响应、凋落物特别是地下凋落物分解对全球气候变化的响应机制等方面．     

Inundation,Vegetation, and Sediment Effects on Litter Decomposition in Pacific Coast Tidal Marshes

The cycling and sequestration of carbon are important ecosystem functions of estuarine wetlands that may be affected by climate change. We conducted experiments across a latitudinal and climate gradient of tidal marshes in the northeast Pacific to evaluate the effects of climate- and vegetation-related factors on litter decomposition. We manipulated tidal exposure and litter type in experimental mesocosms at two sites and used variation across marsh landscapes at seven sites to test for relationships between decomposition and marsh elevation, soil temperature, vegetation composition, litter quality, and sediment organic content. A greater than tenfold increase in manipulated tidal inundation resulted in small increases in decomposition of roots and rhizomes of two species, but no significant change in decay rates of shoots of three other species. In contrast, across the latitudinal gradient, decomposition rates of Salicornia pacifica litter were greater in high marsh than in low marsh. Rates were not correlated with sediment temperature or organic content, but were associated with plant assemblage structure including above-ground cover, species composition, and species richness. Decomposition rates also varied by litter type; at two sites in the Pacific Northwest, the grasses Deschampsia cespitosa and Distichlis spicata decomposed more slowly than the forb S. pacifica. Our data suggest that elevation gradients and vegetation structure in tidal marshes both affect rates of litter decay, potentially leading to complex spatial patterns in sediment carbon dynamics. Climate change may thus have direct effects on rates of decomposition through increased inundation from sea-level rise and indirect effects through changing plant community composition.     

天童国家森林公园常见植物凋落叶分解的研究

 选择天童地区常绿阔叶林及其退化群落常见植物种为对象,着重探讨分解速率和基质营养含量以及比表面积(Specific Leaf Area, SLA)的关系,并试图通过单独分解试验和混合分解试验的比较,从物种、功能群角度探讨凋落叶多样性和分解这一生态系统过程的关系,为深入研究常绿阔叶林常见植物种的营养策略、群落养分循环等奠定基础,也为植被恢复、森林生态系统管理提供理论依据。结果表明：所有凋落叶随时间进程失重率增大,但失重率并不与时间呈线性相关;凋落叶分解后N、P均发生了变化,大多数凋落叶在分解初期N、P均发生了积累,营养元素的释放和富集与凋落叶初始营养状况无明显的相关性。凋落叶的年分解系数与凋落叶中的初始N含量有较高的相关性,而与初始P含量则无显著的相关性;凋落叶的分解速率与成熟叶的面积无相关性,而与其SLA有很强的相关性。通过模型分析,天童地区大多数常见树种凋落叶分解95%需1～4年,平均是2.54年;分解率最高的物种为山鸡椒(Litsea cubeba),其值为6.280,最低的为黄丹木姜子(Litsea elongata),其值为0.558。凋落物混合对分解有很大的影响,虽在初期对分解有阻碍作用,但长期是促进的。若不考虑功能群差异,则可得出多样性的增加有利于分解的结论。功能群数目的增加在凋落物分解前期对分解起促进作用,但这种作用随分解的进展逐渐减小。混合物种的特性往往是决定分解过程的最重要的因素。     

减雨对南亚热带马尾松人工林凋落物分解的影响

为探究气候变化背景下降雨格局改变对马尾松人工林凋落物分解及养分释放过程的影响,以南亚热带马尾松(Pinus massoniana)人工林为研究对象,设置穿透雨减少50%和不减雨(对照)处理,开展连续观测野外降水控制实验。采用凋落物分解袋法,研究了减雨处理对南亚热带马尾松人工林凋落叶分解速率及养分释放的影响,以及凋落叶分解速率的影响因素。结果表明:凋落叶分解2年后,减雨处理和对照林凋落叶残留率分别为38.09%和38.06%;凋落叶分解过程中碳元素表现为淋溶-富集-释放,而氮元素表现为富集,减雨50%在一定程度上促进了氮的富集,但未达到显著水平。相关分析表明,凋落叶的残留率与氮浓度和月积温呈显著负相关,与碳/氮呈显著正相关。本研究发现,减雨50%并未改变马尾松凋落叶分解速率和养分释放模式,凋落叶的残留率与氮浓度、碳/氮及月积温密切相关。     

季节性雪被变化对森林凋落物分解及土壤氮动态的影响

全球气候变化引发的雪被格局变化将深刻影响植被的凋落物分解、陆地生态系统的土壤养分循环等过程.森林是陆地生态系统的主体,在全球生物地球化学循环中起着不可替代的作用.本研究综述了季节性雪被变化对森林凋落物分解及土壤氮动态的影响.全球气候变化情景下季节性雪被表现出因地域而异的增加或减少的变化格局,一方面通过改变环境温湿度、凋落物质量、分解者动态等直接影响分解过程,另一方面通过改变森林群落结构、植被物候、土壤养分等间接地作用于凋落物分解.同时,季节性雪被通过影响氮富集作用、雪被下土壤温湿度、冻融循环、森林群落、雪下动物和微生物等相关因子而改变森林土壤氮循环.本领域未来应开展的研究是: 1) 全面考虑全球气候变化情景下季节性雪被格局的变异性,开展不同季节性雪被格局变化的模拟研究;2) 开展季节性雪被融雪水淋溶作用对森林凋落物分解和土壤氮动态的影响研究;3) 阐明不同生态系统和气候带中季节性雪被格局变化对森林凋落物分解过程和土壤氮动态的驱动机制研究;4) 量化季节性雪被变化对森林凋落物分解和土壤氮动态在雪被覆盖期的瞬时影响和无雪期的延续影响,为阐明和模型预测陆地生态系统生物地球化学循环对全球气候变化的响应提供理论基础和数据支持.     

An integrated assessment of ecosystem carbon pools and fluxes across an oceanic alpine toposequence

Alpine ecosystems are predicted to be severely affected by climate change. Cold, wet oceanic-alpine environments may also accumulate large total ecosystem carbon (C) pools, but have rarely been investigated. We assessed C pools and fluxes on a toposequence of oceanic-alpine habitats from blanket mire and boreal Calluna heath to Racomitrium heath, Nardus snowbed and alpine Calluna heath. We quantified C pools in vegetation and soils for each habitat and compared these with C inputs from net primary production (NPP) and outputs via decomposition, measured in a 3-year litter bag experiment. We also investigated principle drivers (temperature, moisture, community composition) of C pool and flux differences between habitats. Total ecosystem C pools were large; 11–26 kg C m^?2 in alpine habitats and 50 kg C m^?2 in blanket mire. Within the alpine zone C storage was greatest in the snowbed. Litter decomposition was slow in all habitats (k?=?0.09–0.29 y^?1) while NPP was within the range reported for continental alpine systems. C pool sizes and C fluxes did not vary consistently with altitude but reflected topographic gradients of temperature and moisture within the alpine zone. Oceanic-alpine ecosystems contain large stores of C which may be vulnerable to the effects of climate change.