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1.
Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in the Sanjiang Plain, China using different mesh litterbags. The results show that in each succession stage of wetland, soil fauna can obviously increase litter decomposition rates. The average contribution of whole soil fauna to litter mass loss was 35.35%. The more complex the soil fauna group, the more significant the role of soil fauna. The average loss of three types of litter in the 4mm mesh litterbags was 0.3–4.1 times that in 0.058mm ones. The decomposition function of soil fauna to litter mass changed with the wetland succession. The average contribution of soil fauna to litter loss firstly decreased from 34.96% (Carex lasiocapa) to 32.94% (Carex meyeriana), then increased to 38.16% (Calamagrostics angustifolia). The contributions of soil fauna to litter decomposition rates vary according to the litter substrata, soil fauna communities and seasons. Significant effects were respectively found in August and July on C. angustifolia and C. lasiocapa, while in June and August on C. meyeriana. Total carbon (TC), total nitrogen (TN) and total phosphorus (TP) contents and the C/N and C/P ratios of decaying litter can be influenced by soil fauna. At different wetland succession stages, the effects of soil fauna on nutrient elements also differ greatly, which shows the significant difference of influencing element types and degrees. Soil fauna communities strongly influenced the TC and TP concentrations of C. meyeriana litter, and TP content of C. lasiocapa. Our results indicate that soil fauna have important effects on litter decomposition and this influence will vary with the wetland succession and seasonal variation. Foundation item: Under the auspices of State Key Development Program for Basic Research of China (No. 2009CB421103), Key Program of National Natural Science Foundation of China (No. 40830535/D0101), Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-BR-16, KSCX2-YW-N-46-06)  相似文献   

2.
Microorganisms are nutritious resources for various soil fauna.Although soil fauna grazing affects microorganism composition and decomposition rate,the responses of soil fauna and leaf litter decomposition to added microorganism is little understood.In this study,in the coniferous and broad-leaved mixed forest of Tahe County in the northern Da Hinggan Mountains,China,three sampling sites(each has an area of 10 m2) were selected.The first two sites were sprinkled with 250 times(EM1) and 1000 times(EM2) diluted effective microorganism(EM) preparations evenly,and the third site was sprinkled with the same volume of water as a control site.The responses of soil fauna structure and leaf litter decomposition to EM treatment were conducted during three years.The results revealed that EM treatment resulted in significant increase of soil organic matter.The number of soil fauna in the EM1 and EM2 sites increased by 12.88% and 2.23% compared to the control site,and among them springtails and mites showed the highest increase.However,the groups of soil fauna in the EM1 and EM2 sites decreased by 6 and 9,respectively.And the changes in the diversity and evenness index were relatively complicated.EM treatment slowed the decomposition of broad-leaved litter,but accelerated the decomposition of coniferous litter.However,the decomposition rate of broad-leaved litter was still higher than that of coniferous litter.The results of this study suggested that the added microorganisms could help individual growth of soil fauna,and this method led to a change in the process of leaf litter decomposition.This paper did not analyze the activity of soil microorganisms,thus it is difficult to clearly explain the complex relationships among litter type,soil fauna and soil microorganisms.Further research on this subject is needed.  相似文献   

3.
During the period of May to October in 1999, systematical studies were given to the rate of decomposition of Calamagrostis angustifolia litter, the phosphorus content and weight in decomposed residua of litter, and phosphorus content in the corresponding soil in the Sanjiang Plain. At the same time, the simulation models were listed in the paper. The results showed that the rate of weight lost of decomposition of Calamagrostis angustifolia litter is 29.80% and the maximum of daily rate of weight lost is 0.25%, which appeared in July. The change trend of phosphorus content and weight in the decomposed residua of litter is to reduce with the decomposing process, when it comes to the day of 157, the decrement amount of the both were respectively 57.69mg/kg and 1.6199mg, which were 72.80% and 76.30% of its previous amount. In addition, there is a polynomial minus correlationship of phosphorus content between the variation in corresponding soil and the decomposed residua of litter at the corresponding period. The study will be helpful to further understand the process and mechanism of biochemical cycling of nutrient elements in wetland ecosystems, in addition, it will also be helpful to the restoration and rebuilding of retrogressive wetlands and reasonable development and utilization of wetlands in the Sanjiang Plain. Foundation item: Under the auspices of the National Natural Science Fundation of China (No. 49771002), the Key B Items of Chinese Academy of Sciences (KZ951-B1-201-3) and the Innovative Project of the Chinese Academy of Sciences (KZCX2-302). Boigraphy: WANG Shi-yan (1974 -), male, a native of Jinan City, Shandong Province, Ph. D. candidate of Changchun Institute of Geography, the Chinese Academy of Sciences. His research interests include ecology of wetland environment and application of remote sensing and GIS.  相似文献   

4.
Ｅｌｅｍｅｎｔｓｃｙｃｌｉｎｇａｎｄｅｎｅｒｇｙｆｌｏｗａｒｅｔｈｅｉｍｐｏｒｔａｎｔｒｅｓｅａｒｃｈｃｏｎｔｅｎｔｓｉｎｅｃｏｓｙｓｔｅｍｆｉｅｌｄｓａｎｄｒｅｓｉｄｕａｄｅ-ｃｏｍｐｏｓｉｔｉｏｎｉｓｔｈｅｋｅｙｐｒｏｃｅｓｓｏｆｎｕｔｒｉｍｅｎｔａｌｅｌｅｍｅｎｔｓｃｉｒｃｕｌａｔｉｏｎＳＷＩＦＴｅｔａｌ．１９７９．Ｔｈｅｒｅｓｉｄｕａｄｅ-ｃｏｍｐｏｓｉｔｉｏｎｒａｔｅｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｄｅｃｉｄｉｎｇｔｈｅｐｒｏｄｕｃｔｉｖｉｔｙａｎｄｂｉｏｍａｓｓｏｆ…  相似文献   

5.
Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as collection of wood for fuel purpose and livestock grazing. Removal of vegetation of rangelands has a significant negative impact on soil organic matter(SOM). This research evaluates litter decomposition in three sites of Hazarganji Chiltan mountain with varying history of human disturbances(unprotected site, young protected site and old protected site). Twigs of Pistacia khinjuk with approximately equal weight and length were placed in litter bags of mesh size 2 mm and were buried in 0-5 cm depth in three sites in January. Half of the twigs of each site received rain simulation in April, August, October, November and January while the other half of the twigs were subjected under natural conditions for 15 months. Twigs from each plot of each treatment of each site were collected from soil after every rain simulation in the previous month of experiment and were processed for weight loss assessment. Results showed that weight loss of twigs by decomposition was significantly higher in the soil of unprotected site as compared to other two sites and there was no difference between rain simulation and control treatments except that loss of weight of twigs of unprotected site was higher under control than rain simulation condition. To confirm that SOM was the major controlling factor for the decomposition of litter decay, soils of each site were collected and burned to remove SOM;thereafter, burned soil samples were mixed with homogenous powder of oven-dried native plants, incubated for 6 months and were provided with dissolved organic matter of the soils of each site. Results showed that there was no difference in the decomposition of litter between soils under controlled laboratory condition, which confirmed that SOM was a major controlling factor for the litter decay in soil under field conditions. The pyrosequencing analysis of the DNA of soils collected from three sites revealed the presence of bacterial species Thermovum composti.  相似文献   

6.
The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area.The authors collected the samples of forest litter (Tilia amurensis,Fraxinus mandshurica,Pinus koraiensis,Acer mono,Betula costata,and mixed litter),soil in humus horizon (0-5cm) and soil horizon (5-20cm),and soil macrofauna (Oligochaeta,Geophiloporpha and Juliformia) from 2001 to 2002.The role of soil macrofauna in the material cycle was analyzed through comparing the macro-element contents among various parts of the subsystems and using enrichment index (EI).The results indicate that dynamic changes of various litters are very complicated.The contents of Fe in each kind of litter increase firstly,and then decrease in the study period.The changes of macro-element contents are greater in the broad-leaf litter than in the coniferous litter,and the mixed litter is in the middle level,but the differences among them are not significant.The contents of Mg and Fe in humus are higher than those in soil,but the contents of Ca in soil are higher than that in humus.The dynamic changes of macro-element contents in soil and soil fauna are not consistent with those in litter.The diplopod presented obvious enrichment of Ca and Mg (EI>1),but it does not significantly enrich Fe.Earthworm has a stronger enrichment ability of Fe than diplopod and scolopendra,but EI<1.Soil fauna can make great influences on the material cycle of the subsystems.  相似文献   

7.
Broad leaved pine forests are the typical zonal vegetation and its central distribution zone is in the Changbai Mountains in northeast China. However, because of man's disturbance and destruction, primitive broad leaved pine forests exist now only in a few areas such as the Changbai Mountains of Jilin Province and Wuying, Liangshui Natural Reserves of Heilongjiang Province, and the forests in other places are substituted by natural secondary forests (WANG, 1994). Broad leaved pine …  相似文献   

8.
The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter （Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, Betula costata, and mixed litter）, soil in humus horizon （0--5cm） and soil horizon （5-20cm）, and soil macrofauna （Oligochaeta, Geophiloporpha and Juliformia） from 2001 to 2002. The role of soil macrofauna in the material cycle was analyzed through comparing the macro-element contents among various parts of the subsystems and using enrichment index （El）. The results indicate that dynamic changes of various litters are very complicated. The contents of Fe in each kind of litter increase firstly, and then decrease in the study period. The changes of macro-element contents are greater in the broad-leaf litter than in the coniferous litter, and the mixed litter is in the middle level, but the differences among them are not significant. The contents of Mg and Fe in humus are higher than those in soil, but the contents of Ca in soil are higher than that in humus. The dynamic changes of macro-element contents in soil and soil fauna are not consistent with those in litter. The diplopod presented obvious enrichment of Ca and Mg （E1〉1）, but it does not significantly enrich Fe. Earthworm has a stronger enrichment ability of Fe than diplopod and scolopendra, but E1〈1. Soil fauna can make great influences on the material cycle of the subsystems.  相似文献   

9.
The raising concentration of atmospheric CO_2 resulted in global warming. The forest ecosystem in Tibet played an irreplaceable role in maintaining global carbon balance and mitigating climate change for its abundant original forest resources with powerful action of carbon sink. In the present study, the samples of soil and vegetation were collected at a total of 137 sites from 2001 to 2018 in Tibet. Based on the field survey of Tibet's forest resources and 8~(th) forest inventory data, we estimated the carbon storage and carbon density of forest vegetation(tree layer, shrub, grass, litter and dead wood) and soil(0-50 cm) in Tibet. Geostatistical methods combined with Kriging spatial interpolation and Moran's I were applied to reveal their spatial distribution patterns and variation characteristics. The carbon density of forest vegetation and soil in Tibet were 74.57 t ha~(-1) and 96.24 t ha~(-1), respectively. The carbon storage of forest vegetation and soil in Tibet were 344.35 Tg C and 440.53 Tg C, respectively. Carbon density of fir(Abies forest) was 144.80 t ha~(-1) with the highest value among all the forest types. Carbon storage of spruce(Picea forest) was the highest with 99.09 Tg C compared with other forest types. The carbon density of fir forest and spruce forest both increased with the rising temperature and precipitation. Temperature was the main influential factor. The spatial distribution of carbon density of forest vegetation, soil, and ecosystem in Tibet generally showed declining trends from western Tibet to eastern Tibet. Our results facilitated the understanding of the carbon sequestration role of forest ecosystem in the Tibet. It also implied that as the carbon storage potential of Tibet's forests are expected to increase, these forests are likely to serve as huge carbon sinks in the current era of global warming and climate change.  相似文献   

10.
Soil respiration from decomposing aboveground litter is a major component of the terrestrial carbon cycle. However, variations in the contribution of aboveground litter to the total soil respiration for stands of varying ages are poorly understood. To assess soil respiration induced by aboveground litter, treatments of litter and no litter were applied to 5-, 10-, and 20-year-old stands of Populus davidiana Dode in the sandstorm source area of Beijing-Tianjin, China. Optimal nonlinear equations were applied to model the combined effects of soil temperature and soil water content on soil respiration. Results showed that the monthly average contribution of aboveground litter to total soil respiration were 18.46% ± 4.63%, 16.64% ± 9.31%, and 22.37% ± 8.17% for 5-, 10-, and 20-year-old stands, respectively. The relatively high contribution in 5- and 20-year-old stands could be attributed to easily decomposition products and high accumulated litter, respectively. Also, it fluctuated monthly for all stand ages due to substrate availability caused by phenology and environmental factors. Litter removal significantly decreased soil respiration and soil water content for all stand ages (p < 0.05) but not soil temperature (p > 0.05). Variations of soil respiration could be explained by soil temperature at 5-cm depth using an exponential equation and by soil water content at 10-cm depth using a quadratic equation, whereas soil respiration was better modeled using the combined parameters of soil temperature and soil water content than with either soil temperature or soil water content alone. Temperature sensitivity (Q 10) increased with stand age in both the litter and the no litter treatments. Considering the effects of aboveground litter, this study provides insights for predicting future soil carbon fluxes and for accurately assessing soil carbon budgets.  相似文献   

11.
This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling (SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance (harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.  相似文献   

12.
1INTRODUCTIONForestbiodiversityprovidesawiderangeofindirectbenefitstohumanbeing.Whiletheremaybelittlecon-sensusonwhetherthevariouselementsofforestbiodi-versitycanbevaluedineconomicterms, itisincreas-inglyrecognizedthatthesevaluesandtheroleofbio-diversityinmaintainingecologicalservicesareessen-tialtothehumankind.Thenotionofindirectusevalueofbiodiversityhasbeenassociatedwithaminimumlevelofecosysteminfrastructure, withoutwhichtherewouldnotbethegoodsandservicesprovidedbyit(FARNWORTHetal.,1…  相似文献   

13.
From 2007 to 2009, large-scale blooms of green algae (the so-called “green tides”) occurred every summer in the Yellow Sea, China. In June 2008, huge amounts of floating green algae accumulated along the coast of Qingdao and led to mass mortality of cultured abalone and sea cucumber. However, the mechanism for the mass mortality of cultured animals remains undetermined. This study examined the toxic effects of Ulva (Enteromorpha) prolifera, the causative species of green tides in the Yellow Sea during the last three years. The acute toxicity of fresh culture medium and decomposing algal effluent of U. prolifera to the cultured abalone Haliotis discus hannai were tested. It was found that both fresh culture medium and decomposing algal effluent had toxic effects to abalone, and decomposing algal effluent was more toxic than fresh culture medium. The acute toxicity of decomposing algal effluent could be attributed to the ammonia and sulfide presented in the effluent, as well as the hypoxia caused by the decomposition process.  相似文献   

14.
The effects of reforestation on carbon(C) sequestration in China′s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees(Robinia pseudoacacia L.) are valued for their important use in reforestation and water and soil conservation efforts. This forest type is widespread across the Loess Plateau, and must be an essential component of any planning for C sequestration efforts in this fragile ecological region. The long-term effects of stand age on C accumulation and allocation after reforestation remains uncertain. We examined an age-sequence of black locust forest(5, 9, 20, 30, 38, and 56 yr since planting) on the Loess Plateau to evaluate C accumulation and allocation in plants(trees, shrubs, herbages, and leaf litter) and soil(0–100 cm). Allometric equations were developed for estimating the biomass of tree components(leaf, branch, stem without bark, bark and root) with a destructive sampling method. Our results demonstrated that black locust forest ecosystem accumulated C constantly, from 31.42 Mg C/ ha(1 Mg = 10~6 g) at 5 yr to 79.44 Mg C/ha at 38 yr. At the ′old forest′ stage(38 to 56 yr), the amount of C in plant biomass significantly decreased(from 45.32 to 34.52 Mg C/ha) due to the high mortality of trees. However, old forest was able to accumulate C continuously in soil(from 33.66 to 41.00 Mg C/ha). The C in shrub biomass increased with stand age, while the C stock in the herbage layer and leaf litter was age-independent. Reforestation resulted in C re-allocation in the forest soil. The topsoil(0–20 cm) C stock increased constantly with stand age. However, C storage in sub-top soil, in the 20–30, 30–50, 50–100, and 20–100 cm layers, was age-independent. These results suggest that succession, as a temporal factor, plays a key role in C accumulation and re-allocation in black locust forests and also in regional C dynamics in vegetation.  相似文献   

15.
Mountainous areas exhibit highly variable decomposition rates as a result of strong local differences in climate and vegetation type. This paper describes the effect of these factors on two major determinants of the local carbon cycle: litter decomposition and carbon stabilization. In order to adequately reflect local heterogeneity, we have sampled 12 typical plant communities of the Russian Caucasus. In order to minimize confounding effects and encourage comparative studies, we have adapted the widely used tea bag index (TBI) that is typically used in areas with low decomposition. By incubating standardized tea litter for a year, we investigated whether (1) initial litter decomposition rate (k) is negatively correlated with litter stabilization (S) and (2) whether k or S exhibit correlations with altitude and other environmental conditions. Our results show that S and k are not correlated. Altitude, pH, and water content significantly influenced the stabilization factor S, while soil-freezing had no influence. In contrast, none of these factors predicted the decomposition rate k. Based on our data, we argue that collection of decomposition rates alone, as is now common practice, is not sufficient to understand carbon input to soils and can potentially lead to misleading results. Our data on community-specific decomposition and stabilization rates further constrain estimates of litter accumulation in subalpine communities and the potential effects of climate change.  相似文献   

16.
浙江省森林生态服务价值估算及其逐月变异分析   总被引：1，自引：0，他引：1  
森林生态服务价值的研究对构建绿色GDP核算体系、制定生态补偿标准、提高人类环境保护意识等有十分重要的意义。本文首先以卫星影像、地理空间数据、站点记录等资料,结合GIS、RS技术,估算了浙江省森林生态系统2010年的NPP、蒸散量、土壤保持量等;然后,采用能量替代法、机会成本法、影子工程法等估算了浙江省森林2010年的固碳释氧价值、有机物生产价值、水源涵养价值、营养物循环价值、水土保持价值;最后,对各种生态服务价值的逐月变异规律进行分析。结果表明：浙江省森林2010年的5种生态服务价值呈现明显的逐月变异规律;固碳释氧价值、有机物生产价值、营养物质循环价值、水土保持价值的逐月变异规律,均可用开口向下抛物线拟合;水源涵养价值的逐月变异规律,可用开口向上抛物线拟合。  相似文献   

17.
The effects of acid deposition on pine forest ecosystems in Longli of Guizhou Province, southwestern China are studied using indoor experiments and model simulations. Indoor experiments are designed to explore the aluminum toxicity on pine seedlings, and the long-term soil acidification model（LTSAM） and a terrestrial biogeochemistry model（CENTURY） are used to simulate the influences of acid deposition on pine forest ecosystems. The indoor experiment results of aluminum toxicity show that aluminum ions in solution limit plant growth and acid deposition enhances this effect by facilitating the release of aluminum ions from the soil. Pine seedling biomass and root elongation decrease as the aluminum concentration increases. The results of model simulations show that the soil chemistry varies significantly with different changes in acid deposition. When the acid deposition increases, the pH value in the soil solution decreases and the soil Al3+ concentration increases. The increased acid deposition also has negative impacts on the forest ecosystem, i.e., decreases plant biomass, net primary productivity（NPP） and net CO2 uptake. As a result, the soil organic carbon（SOC） decreases because of the limited supply of decomposition material. Thus acid deposition need be reduced to help protect the forest ecosystems.  相似文献   

18.
遥感地表能量信息通过空间分布及变化趋势体现生态系统要素的格局、状态、质量,客观反映城市生态系统的状态,是度量区域生态系统要素生态过程的重要内容。本文以三亚市热带雨林植被环境的地表能量综合响应特征和作用、影响关系特征为基础,采用植被指数分级、地表能量分级和植被-能量关系等指标,结合雨林垂直分带和植被分布信息,探讨近30年（1987-2016年）不同时期热带雨林环境的水平地带性、垂直地带性及其时空变化特征。结果表明：①近30年三亚市域植被覆盖比例维持在90%左右,植被指数分级构成以高、中数值分布为主,并呈现整体趋高态势。②各级地表能量分布比例的波动幅度在10%之内,中等地表能量级别范围呈现向低地表能量区域扩展趋势。③随着海拔高度的提升,植被指数高数值的热带雨林分布比例增加,地表能量值降低。④热带雨林的地表能量和植被指数的时空分布稳定性均高于人工植被。本文基于遥感地表能量综合响应特征和作用、影响关系特征建立的指标评价体系,可以为热带雨林生态系统的量化评价提供支持。  相似文献   

19.
以流域作为山-水-林-田-湖-草生命共同体的研究尺度和载体,流域生态学在国家生态文明建设中所发挥的学科支撑作用日益重要。“流域生态系统结构-过程-功能-机制-调控”是流域生态学的研究范式,其中空间结构量化及其指标体系构建是流域生态学开展定量研究的一个关键途径。尽管流域生态系统空间结构量化的指标体系涉及到淡水生态学、陆地生态系统生态学、水土保持学、农业环境学和水利工程学等多个学科,但仍未在流域尺度上形成生态系统空间结构整合量化框架体系。基于此,总结了多个关联学科在流域生态系统空间结构量化的研究方法和成果,着重分析了流域生态学在流域尺度上量化生态系统空间结构的难点,并重点以等级结构和集合生态系统理论为基础构建了流域生态系统空间结构量化指标体系,包括流域整体指标、各结构成分指标和结构成分间关系指标,为量化流域生态系统空间结构和结构成分之间关系提供了新方法,对尝试推动流域生态学在山-水-林-田-湖-草生命共同体的耦合定量研究及评估应用具有重要的科学价值。  相似文献   

20.
Ecosystem service is an emerging concept that grows to be a hot research area in ecology. Spatially explicit ecosystem service values are important for ecosystem service management. However, it is difficult to quantify ecosystem services. Remote sensing provides images covering Earth surface, which by nature are spatially explicit. Thus, remote sensing can be useful for quantitative assessment of ecosystem services. This paper reviews spatially explicit ecosystem service studies conducted in ecology and remote sensing in order to find out how remote sensing can be used for ecosystem service assessment. Several important areas considered include land cover, biodiversity, and carbon, water and soil related ecosystem services. We found that remote sensing can be used for ecosystem service assessment in three different ways: direct monitoring, indirect monitoring, and combined use with ecosystem models. Some plant and water related ecosystem services can be directly monitored by remote sensing. Most commonly, remote sensing can provide surrogate information on plant and soil characteristics in an ecosystem. For ecosystem process related ecosystem services, remote sensing can help measure spatially explicit parameters. We conclude that acquiring good in-situ measurements and selecting appropriate remote sensor data in terms of resolution are critical for accurate assessment of ecosystem services.  相似文献   

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