不同海拔缓步动物群落结构的比较

为研究海拔对缓步动物群落结构的影响,对地处秦岭北坡的南五台山缓步动物群落进行了初步调查研究.调查设置3个样区、45个样方,共采集缓步动物919个,个体密度平均816.89个·m-2,隶属缓步动物门2纲2目3科7属11种.其中Macrobiotus hufelandi和M.harmsworthi共占总采量的92.93%,为优势类群.采用Simpson指数、Shannon-Wiener信息指数、Pielou均匀度指数和修正的Hill指数来计算各生境缓步动物群落结构特点.研究表明,海拔对缓步动物群落结构有一定的影响.随着海拔的下降其物种的个体数量、群落优势类群的数量和优势物种数都呈下降趋势;物种多样性的变化趋势为中海拔地区＞低海拔地区＞高海拔地区,而群落优势度的变化趋势完全相反;不同海拔样区的群落相似性较低.     

Microbial genetic diversity and ciliate community structure along an environmental gradient in coastal soil

We investigated the microbial genetic diversity and ciliate community in coastal soil from five sites with an environmental gradient using denaturing gradient gel electrophoresis (DGGE), gene sequencing and the Ludox–QPS method. The analyses of both the 16S ribosomal RNA (rRNA) gene and 18S rRNA gene DGGE resulted in equal or even a higher number of bands found in the samples taken from the high-salinity sites IV and V than in those taken from the low-to-moderate-salinity sites I–III. Cluster analysis of both DGGE profiles classified the five sites into three main groups (sites I, II and III and IV and V), which corresponded well to the analysis of environmental factors. There were 13 species observed at site I, three species at site II and nine species at site III, while no active ciliates were observed at the high-salinity sites IV and V. By contrast, the ciliate-specific DGGE revealed a higher number of bands in the samples taken from the high-salinity soil. Furthermore, gene sequencing suggested that the ciliates in the high-salinity soil comprised forms originating not only from soil but also from marine environments. The data indicate that saline soil may maintain a high diversity of ciliates and soil salinity might be the most influential factor regulating the community structure of ciliates.     

珠穆朗玛峰不同海拔梯度上土壤细菌和真菌群落变化特征

高寒生态系统是全球变化的敏感区域,揭示高海拔地区尤其是雪线以上土壤微生物群落的演变规律,对于理解全球气候变化对高寒生态系统的影响及其响应机制具有重要意义。以采自青藏高原珠穆朗玛峰北坡低海拔地区和永久雪线以上(海拔4000—6550m)的12份土壤和砂砾样品为研究对象,运用活菌计数法(CFU)和实时定量PCR(real-time PCR)技术对土壤样品的细菌和真菌进行了定量分析,并结合磷脂脂肪酸(PLFA)分析法、变性梯度凝胶电泳技术(DGGE)和克隆测序方法研究了细菌和真菌群落随海拔梯度变化的演变特征,结果表明:土壤细菌和真菌丰度随海拔增加而降低,与海拔高度呈显著负相关;磷脂脂肪酸分析结果表明不论是细菌、真菌还是总的微生物PLFA含量均随海拔高度增加而下降,革兰氏阴性细菌和革兰氏阳性细菌的多样性也随海拔增加而降低,且代表革兰氏阳性细菌的PLFA组份在雪线(5350m)以上检测不到,而代表革兰氏阴性细菌和真菌的组份在所有海拔梯度上都有分布,表明革兰氏阳性细菌比阴性细菌和真菌对海拔及海拔相关因子变化更为敏感。DGGE图谱的UPGMA聚类分析的结果也发现在不同海拔高度样品中细菌群落组成发生明显变化,但真菌群落变化不明显。测序分析结果显示变形菌纲(Proteobacteria)是珠峰不同海拔高度土壤/砂砾样品中的优势菌群,芽单胞菌(Gemmatimonadetes)是高海拔样品中的优势菌群,而放线菌(Actinobacteria)主要分布在低海拔样品中;真菌以子囊菌门(Ascomycota)为主,而丝足虫类(Cercozoa)原生生物是高海拔冰雪覆盖样品所特有的真核生物。     

藏东南森林土壤微生物群落结构与土壤酶活性随海拔梯度的变化

【目的】针对青藏高原藏东南地区色季拉山不同海拔森林土壤,探讨微生物群落与土壤酶活性之间的联系以及受控因子。【方法】利用微生物细胞膜磷脂(PLFA)方法研究土壤微生物群落结构随海拔变化情况,分析土壤葡萄糖苷酶、酚氧化酶、蛋白酶、L-天冬酰胺酶、脲酶和酸性磷酸酶活性以及土壤理化性质随海拔的变化趋势。【结果】土壤理化性质和生化指标随海拔增高没有显著变化,如水分含量、有机碳、全氮、碳氮比、pH、无机氮和硝态氮,土壤葡萄糖苷酶、酚氧化酶、蛋白酶、L-天冬酰胺酶和酸性磷酸酶活性等;然而,微生物丰度呈现中峰优势分布规律,细菌、真菌、革兰氏阳性菌、革兰氏阴性菌和放线菌含量在海拔3 900 m和4 000 m处生物量显著高于低海拔和更高海拔。皮尔森相关性分析表明土壤pH是影响微生物群落结构的主要因子,但海拔梯度上的温度变化与微生物群落结构和酶活性不存在显著相关性;同时,有机碳、全氮、水溶性有机碳和水溶性有机氮和pH等理化指标与土壤酶活性显著相关。【结论】在藏东南色季拉山森林生态系统,海拔梯度对土壤微生物群落结构影响较大,土壤理化指标与生物特征对海拔梯度的响应较弱。     

Macrofaunal community bioturbation along an estuarine gradient

A multidisciplinary study of the impact of bioturbation on sediment dynamics has been underway for some time at the Plymouth Marine Laboratory. The current programme has been founded upon the careful selection of six sites in the River Tamar, representative of important combinations of physical and biological variables. The paper presents preliminary results illustrating the contrasting importance of the speciesNereis diversicolor andNephtys hombergi as agents of bioturbation, given their different distributions across the six sites. Thus bioirrigation byN. diversicolor increases up the estuary and is greatest in the region of high suspended bed-load due to tidal pumping, where the consequences for chemical exchange processes between sediments and the water column may be most important. The sediment mixing effects ofN. hombergi are likely to be greater towards the seaward end of the estuary but ultimately the particular sediment types and the macrofaunal communities they support dictate the level of bioturbation in ways that do not necessarily relate to simple axial gradients along the estuary.     

广西猫儿山沿海拔梯度的叶蜂多样性

在猫儿山自然保护区沿海拔梯度设置7个样地进行叶蜂调查.共采获叶蜂803头,隶属3科58属121种.统计分析表明,异鳞纹眶叶蜂(Claremontia sinobirmana Malaise)和南华平缝叶蜂(Nesoselandria southaWei)为优势种和广布种.不同海拔叶蜂群落的物种丰富度指数、Simpson多样性指数和Shannon-Wiener多样性指数均以中间海拔(1000~1500m)最高,分别为12.293、0.971和3.830;优势度指数则以高海拔最高.聚类分析显示,7个样地的叶蜂物种可以分为高海拔组(>2000m)和其它海拔组(<2000m).相关分析表明,降水量和植被种类是影响叶蜂多样性的主要因素.     

毛竹林土壤酶活性变化的海拔效应

在毛竹分布南缘的中亚热带与南亚热带气候过渡区,选择土壤类型、坡度、坡向、经营水平等一致的3个海拔高度(低海拔90～120m、中海拔360～400m、高海拔700～780m)毛竹林,对其土壤酶活性和物理、化学性质进行了测定。磷酸酶、蔗糖酶和脲酶活性分别为0.031～0.042、0.104～0.146和0.017～0.039mg·g-1.h-1,中海拔是3种酶活性显著变化的转折点。蛋白酶活性为0.248～0.259mg·g-1.h-1,随海拔的升高酶活性缓慢提高。过氧化氢酶活性为0.097～0.143mg·g-1.h-1,随海拔的升高酶活性显著上升。不同海拔高度毛竹林土壤物理性质对土壤酶活性无显著影响。土壤有机质、全氮、碱解氮含量与土壤酶活性呈显著或极显著正相关,pH值对土壤酶活性具正效应,海拔梯度上的土壤全磷、全钾、速磷、速钾含量对土壤酶活性影响不显著。不同种类土壤酶活性间呈显著或极显著相关,酶促反应具专一性和共同性特点。     

Increased methane concentration alters soil prokaryotic community structure along an artificial pH gradient

Global climate change may have a large impact on increased emission rates of carbon dioxide and methane to total greenhouse gas emissions from terrestrial wetlands. Methane consumption by soil microbiota in alpine wet meadows serves as a biofilter for the methane produced in the waterlogged soil below. Altered pH regimes change microbial community composition and structure by exerting selection pressure on soil microorganisms with different ecological strategies and thus affect greenhouse gas emissions resulting from the metabolic activity of soil microorganisms. However, responses of prokaryotic communities to artificial pH shift under elevated methane concentration remain unclear. In this study, we assessed diversity and relative abundance of soil prokaryotes in an alpine meadow under elevated methane concentration along an artificial pH gradient using laboratory incubation experiments. We established an incubation experiment treated with artificial pH gradient (pH 4.5–8.5). After 3 months of incubation, 300 ml of methane at a concentration of 20,000 ppm was added to stimulate potential methanothrophs in topsoil. Sequencing of 16S rRNA gene indicated increasing of relative abundances of Crenarchaeota, Chloroflexi, Bacteroidetes, and Planctomycetes in soil after addition of methane, while the relative abundances of Actinobacteria and Gemmatimonadetes did not significant change before and after methane treatment. Results of phylogenetic relatedness of soil prokaryotes showed that microbial community is mostly shaped by deterministic factors. Species indicator analysis revealed distinct OTUs among various pH and methane treatments. Network analysis revealed distinct co-occurrence patterns of soil prokaryotic community before and after methane addition, and different correlation patterns among various prokaryotic taxa. Linear regression model revealed significant decrease of methane oxidation along elevated pH gradient. Soil pH constituted a strong environmental filter in species assembly of soil prokaryotic community. Methane oxidation rates decreased significantly with elevated pH. The interactive effects of elevated methane concentration and pH are therefore promising topic for future research.     

Microbial community structures in anoxic freshwater lake sediment along a metal contamination gradient

Contamination, such as by heavy metals, has frequently been implicated in altering microbial community structure. However, this association has not been extensively studied for anaerobic communities, or in freshwater lake sediments. We investigated microbial community structure in the metal-contaminated anoxic sediments of a eutrophic lake that were impacted over the course of 80 years by nearby zinc-smelting activities. Microbial community structure was inferred for bacterial, archaeal and eukaryotic populations by evaluating terminal restriction fragment length polymorphism (TRFLP) patterns in near-surface sediments collected in triplicate from five areas of the lake that had differing levels of metal contamination. The majority of the fragments in the bacterial and eukaryotic profiles showed no evidence of variation in association with metal contamination levels, and diversity revealed by these profiles remained consistent even as metal concentrations varied from 3000 to 27 000 mg kg⁻¹ total Zn, 0.125 to 11.2 μ pore water Zn and 0.023 to 5.40 μ pore water As. Although most archaeal fragments also showed no evidence of variation, the prevalence of a fragment associated with mesophilic Crenarchaeota showed significant positive correlation with total Zn concentrations. This Crenarchaeota fragment dominated the archaeal TRFLP profiles, representing between 35% and 79% of the total measured peak areas. Lake DePue 16S rRNA gene sequences corresponding to this TRFLP fragment clustered with anaerobic and soil mesophilic Crenarchaeota sequences. Although Crenarchaeota have been associated with metal-contaminated groundwater and soils, this is a first report (to our knowledge) documenting potential increased prevalence of Crenarchaeota associated with elevated levels of metal contamination.     

Spatial patterns along an elevation gradient in high altitude grasslands,Brazil

The Brazilian high altitude grasslands are important biodiversity centers that contribute to human well‐being far outside their boundaries. They host many vulnerable species that may go locally extinct as a result of small changes in the environment. Performing studies on local species distribution is important to guide biodiversity conservation in these areas. This study aimed to characterize a high altitude grassland plant community along an elevation gradient in southeastern Brazil. Simple logistic regression, chi‐squared tests and indicator species analysis were performed to investigate respectively whether: 1) the occurrence of botanical families was related to the altitude; 2) the richness and abundance of life forms varied along the gradient and 3) there were populations associated with specific altitudinal belts. Rubiaceae and Polygalaceae had higher occurrence probability at higher altitudes. Hemicryptophytes and chamaephytes seem to be the most favored life forms under local extreme conditions such as low temperatures and drought. The vegetation spectra varied significantly along the gradient, highlighting the major role of the turnover of habitats on a local scale for the underlying patterns of species distribution. Upper elevations encompassed a high number of indicator species, and further analyses of indicator species of high altitude grasslands will provide clues about adaptability of local species, important to consider in ecosystem management and conservation.     

Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge

To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37°17'N, 32°16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36°13'N, 33°54.1'W, depth 2270-2330 m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.     

Scavenger community structure along an environmental gradient from boreal forest to alpine tundra in Scandinavia

Scavengers can have strong impacts on food webs, and awareness of their role in ecosystems has increased during the last decades. In our study, we used baited camera traps to quantify the structure of the winter scavenger community in central Scandinavia across a forest–alpine continuum and assess how climatic conditions affected spatial patterns of species occurrences at baits. Canonical correspondence analysis revealed that the main habitat type (forest or alpine tundra) and snow depth was main determinants of the community structure. According to a joint species distribution model within the HMSC framework, species richness tended to be higher in forest than in alpine tundra habitat, but was only weakly associated with temperature and snow depth. However, we observed stronger and more diverse impacts of these covariates on individual species. Occurrence at baits by habitat generalists (red fox, golden eagle, and common raven) typically increased at low temperatures and high snow depth, probably due to increased energetic demands and lower abundance of natural prey in harsh winter conditions. On the contrary, occurrence at baits by forest specialists (e.g., Eurasian jay) tended to decrease in deep snow, which is possibly a consequence of reduced bait detectability and accessibility. In general, the influence of environmental covariates on species richness and occurrence at baits was lower in alpine tundra than in forests, and habitat generalists dominated the scavenger communities in both forest and alpine tundra. Following forecasted climate change, altered environmental conditions are likely to cause range expansion of boreal species and range contraction of typical alpine species such as the arctic fox. Our results suggest that altered snow conditions will possibly be a main driver of changes in species community structure.     

Bacterial diversity,community structure and potential growth rates along an estuarine salinity gradient

Very little is known about growth rates of individual bacterial taxa and how they respond to environmental flux. Here, we characterized bacterial community diversity, structure and the relative abundance of 16S rRNA and 16S rRNA genes (rDNA) using pyrosequencing along the salinity gradient in the Delaware Bay. Indices of diversity, evenness, structure and growth rates of the surface bacterial community significantly varied along the transect, reflecting active mixing between the freshwater and marine ends of the estuary. There was no positive correlation between relative abundances of 16S rRNA and rDNA for the entire bacterial community, suggesting that abundance of bacteria does not necessarily reflect potential growth rate or activity. However, for almost half of the individual taxa, 16S rRNA positively correlated with rDNA, suggesting that activity did follow abundance in these cases. The positive relationship between 16S rRNA and rDNA was less in the whole water community than for free-living taxa, indicating that the two communities differed in activity. The 16S rRNA:rDNA ratios of some typically marine taxa reflected differences in light, nutrient concentrations and other environmental factors along the estuarine gradient. The ratios of individual freshwater taxa declined as salinity increased, whereas the 16S rRNA:rDNA ratios of only some typical marine bacteria increased as salinity increased. These data suggest that physical and other bottom-up factors differentially affect growth rates, but not necessarily abundance of individual taxa in this highly variable environment.     

Virioplankton community structure along a salinity gradient in a solar saltern

The virioplankton community structure along a salinity gradient from near seawater (40 per thousand ) to saturated sodium chloride brine (370 per thousand ) in a solar saltern was investigated by pulsed-field gel electrophoresis. Viral populations with genome sizes varying from 10 kb to 533 kb were detected. The viral community structure changed along the salinity gradient. Cluster analysis of the viral genome-banding pattern resulted in two main clusters. The virioplankton diversity within the samples with salinity from 40 per thousand to 150 per thousand was on the same cluster of a cladogram. The other group consisted of virioplankton from samples with salinity above 220 per thousand. The virioplankton diversity in the different samples was calculated using the Shannon index. The diversity index demonstrated an increase in diversity in the samples along the gradient from 40 per thousand to 150 per thousand salinity, followed by a decrease in the diversity index along the rest of the salinity gradient. These results demonstrate how viral diversity changes from habitats that are considered one of the most common (seawater) to habitats that are extreme in salt concentrations (saturated sodium brine). The diversity index was highest in the environments that lie in between the most extreme and the most common.     

Changes in riverine benthic diatom community structure along a chloride gradient

The application of salt is the primary means of deicing roads and highways in colder regions of north-eastern North America. This has increased the chloride concentrations of many lake and stream ecosystems. While this salinization has been documented, less is known about how increased salinity alters benthic communities in downstream ecosystems. Natural thresholds, at which there are large scale changes in community composition, have not yet been established for many types of contaminants, including chloride. The diatom community, which is sensitive to small changes in the ambient environment, has the potential to be a strong indicator of salinization effects on stream ecosystems. In this study, we sampled diatom communities in 41 streams across a salinity gradient throughout south central Ontario, Canada. We sampled benthic diatom assemblages in early May following complete snowmelt, when stream water chloride concentrations ranged from 5 to 502 mg/L. Based on redundancy analysis, we confirmed a strong association between the species composition of the diatom community and water conductivity, a commonly used index of stream salinity. Taxa indicator threshold analyses (TITAN) indicated the community changed substantially at chloride concentrations greater than 35 mg/L. We also found that, an indicator taxa, Meridion circulare, was extremely sensitive to high concentrations of salt and negatively correlated with chloride. In a wide synoptic survey of streams of our region, we found that streams in most developed watersheds exceed tolerance thresholds for benthic diatom communities. This work suggests that current chloride concentrations in urban watersheds are greatly exceeding the benthic community thresholds, for which improved management and regulatory practices are needed. Salinization thus appears to be an important feature of urban streams and needs to be considered as an important ecological driver in future studies.     

Differences in hyporheic-zone microbial community structure along a heavy-metal contamination gradient

The hyporheic zone of a river is nonphotic, has steep chemical and redox gradients, and has a heterotrophic food web based on the consumption of organic carbon entrained from downwelling surface water or from upwelling groundwater. The microbial communities in the hyporheic zone are an important component of these heterotrophic food webs and perform essential functions in lotic ecosystems. Using a suite of methods (denaturing gradient gel electrophoresis, 16S rRNA phylogeny, phospholipid fatty acid analysis, direct microscopic enumeration, and quantitative PCR), we compared the microbial communities inhabiting the hyporheic zone of six different river sites that encompass a wide range of sediment metal loads resulting from large base-metal mining activity in the region. There was no correlation between sediment metal content and the total hyporheic microbial biomass present within each site. However, microbial community structure showed a significant linear relationship with the sediment metal loads. The abundances of four phylogenetic groups (groups I, II, III, and IV) most closely related to alpha-, beta-, and gamma-proteobacteria and the cyanobacteria, respectively, were determined. The sediment metal content gradient was positively correlated with group III abundance and negatively correlated with group II abundance. No correlation was apparent with regard to group I or IV abundance. This is the first documentation of a relationship between fluvially deposited heavy-metal contamination and hyporheic microbial community structure. The information presented here may be useful in predicting long-term effects of heavy-metal contamination in streams and provides a basis for further studies of metal effects on hyporheic microbial communities.     

Zooplankton community structure along a trophic gradient in a canyon-shaped dam reservoir

The zooplankton community was surveyed along the longitudinalaxis of Rimov Reservoir (Czech Republic) on seven occasionsduring the vegetative season of 1996. The dimictic Rimov Reservoirhas a pronounced trophic gradient along its axis. In nearlyall samples, rotifers were dominant by numbers and formed onaverage 60–95% of the total zooplankton (including copepodnauplii). There was a consistent pattern of increasing relativeabundance of rotifers in the upper regions of the reservoircompared with the downstream parts. Very large rotifer populationscould develop in the upper regions, often associated with floodevents, but also coinciding with reduced abundance of crustaceansassociated with stronger wash-out effects and the advent ofturbid conditions. There was a greater similarity between twoadjacent sites in the proportions of crustacean species thanof rotifer species. This is partially due to the greater speciesdiversity of rotifers than of crustaceans. The timing of theseasonal succession of zooplankton species showed a coherentpattern along the whole longitudinal profile. The site-specificzooplankton patchiness seems to be reduced as there was no sitedependence if average data on zooplankton composition from downstreamlacustrine sites were compared.     

Population abundance gradient of Inurois punctigera along altitude

A winter geometrid moth, Inurois punctigera, shows sympatric and genetically isolated seasonal populations (i.e. early‐ and late‐winter populations) in the cold regions of Japan, whereas it shows only mid‐winter populations in the warm regions. Variation in adult flight phenology on a large geographic scale along latitudinal environmental gradients has been described, but the phenological variation on a more local scale along altitudinal environmental gradients has not yet been characterized. In the present study, we assessed the flight phenology at high‐ and low‐elevation areas in Mt. Rokko, Hyogo, Japan. First, we revealed that flight period was not disrupted in mid‐winter, even at high‐elevation areas (>660 m) but the population abundance was much lower in high‐elevation areas than in low‐elevation areas. Then, in the following two seasons, we investigated I. punctigera abundance, winter harshness (i.e. winter temperature) and their host plant abundance in nine closely located stations in Mt. Rokko. A generalized linear mixed model analysis indicated a greater effect of winter temperature on I. punctigera abundance compared to available food resources, suggesting that differences in winter harshness among elevation shapes the gradient of I. punctigera abundance along altitude. Our findings suggest that harsh conditions during winter function as selective agents on mid‐winter types of I. punctigera, and this could be involved in the divergence between sympatric early‐ and late‐winter populations of I. punctigera.     

Predictable changes in trophic community structure along a spatial disturbance gradient in streams

1. We assessed insect and resource standing stocks along a spatial gradient of flood disturbance in 19 sub-alpine Swedish streams to test the prediction that change in trophic structure arises from the joint action of disturbance, which affect basal resources, and resource-control, which ties the response of the consumers to the response of the resources.
2. Trophic structure, quantified as scores of non-metric multidimensional scaling based on the biomass of insect trophic groups, changed predictably along the disturbance gradient. In early summer, predators and algae feeders decreased relative to suspension feeders with increasing disturbance; in autumn, algae feeders decreased relative to leaf feeders with increasing disturbance.
3. Across the disturbance gradient, the biomass of algae-, deposit- and leaf-feeders was principally controlled by the availability of the respective resource (algae, fine detritus and coarse detritus), while disturbance only had subsidiary effects on algae feeders in early summer.
4. Overall, patterns in trophic-group biomass along the disturbance gradient were more likely to reflect indirect effects of disturbance via impact on the resources, which reverberated to the consumers because of resource-control, rather than direct effects. In contrast with the view that stream communities are the result of stochastic colonization following disturbance events, in the study streams the trophic structure of insect assemblages is predictable and partly organized by resource-control across a broad range of disturbance conditions.     

武夷山不同海拔高度土壤活性有机碳变化

采用连续熏蒸 培养法,测定了福建武夷山自然保护区不同海拔高度具有代表性的中亚热带常绿阔叶林、针叶林、亚高山矮林以及高山草甸土壤中有效碳含量,分析了土壤有效碳（LOC）与微生物量碳（MBC）、土壤总有机碳（TOC）、细根生物量（FRB）和土壤全氮（TN）之间的关系.结果表明：土壤有效碳占总有机碳的3.40%～7.46%;微生物量碳只是土壤有效碳中的一部分,占土壤有效碳26.87%～80.38%; 不同林分土壤有效碳含量随海拔增高而显著增大,随土层深度的增加而降低;土壤有效碳与微生物量碳、土壤总有机碳、细根生物量、土壤全氮之间呈极显著的相关关系.高海拔土壤有效碳含量显著高于低海拔土壤.