Angustifolia Wetland Research Articles

Habitats and nesting habits of Streaked Weaver Ploceus manyar in select wetlands in the northern districts of Tamil Nadu, India

The habitats and nesting habits of Streaked Weaver Ploceus manyar was studied in the Narrow Leaf Cattail Typha angustifolia (Typhaceae) wetlands in Ranipet, Kancheepuram, and Viluppuram districts of northern Tamil Nadu. A total of 349 nests, in various developmental stages, in 24 colonies and of 536 adult individuals were enumerated. Of these 349 nests, 43 nests were in wad stage, 28 in ring stage, 123 in helmet stage, 55 egg-chamber-closed stage, and 100 complete nests including two abnormal nests were recorded. Streaked Weaver used fibres of T. angustifolia for building nests. Females were also observed to be engaged in nest construction, while males placed blobs of cow dung on the inner or both walls of helmet stage nests before pairing with females; 88.7% helmet stage nests had deposition of cow dung on their inner walls and the remaining 11.3% nests had no such deposits. In 59% nests the entrance tubes were found facing east. They showed communal foraging and the flock size ranged from 50─80 birds. No antagonistic interactions were observed between Streaked Weavers and other species over sharing of common perching sites and foraging grounds. Harvesting of nest-supporting reeds and sightings of avian predators, such as House Crow Corvus splendens, Large-billed Crow Corvus macrorhynchos, and Rufous Treepie Dendocitta vagabunda near nest colonies may pose threats to Streaked Weavers.

松嫩平原湿地植物群落多样性的环境梯度分布格局及控制因子

PDF HTML阅读 XML下载 导出引用 引用提醒 松嫩平原湿地植物群落多样性的环境梯度分布格局及控制因子 DOI: 10.5846/stxb202201150145 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中央高校自主科研项目计划（2572019DF07） Environmental gradient distribution patterns of wetland plant community diversity and controlling factors in Songnen Plain Author: Affiliation: Fund Project: Supported by: The Independent Research Project of the Central Universities of China (2572019DF07) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:物种丰富度格局及其决定因素是生态学核心问题，但对其形成机制仍缺乏共识。为探究松嫩平原西部半干旱区沿湖岸至高地环境梯度（局地尺度）植物群落多样性分布格局及其决定因素，以沿该梯度依次分布的7种群落（狭叶香蒲沼泽、小香蒲沼泽、芦苇沼泽、草丛沼泽、拂子茅草甸、羊草草甸和榆树疏林）为对象，采用样带网格调查法及聚类分析法划分群落类型，测定物种丰富度、α多样性和β多样性及其环境因子（水位、土壤含水率、有机质等），揭示群落多样性空间分布规律及其形成机制。结果表明，沿湖岸至高地环境梯度：（1）物种丰富度（2.00-18.00）和α多样性（Simpson指数0.12-0.90；Shannon-Wiener指数0.23-2.57和Pielou指数0.34-0.88）总体上均呈类似N字型分布（在下部深水生境狭叶香蒲沼泽最低、中下部季节性积水生境草丛沼泽最高、中上部湿润生境拂子茅草甸较低、上部沙丘干旱生境榆树疏林又较高）；（2）广义的β多样性（Jaccard指数0.56-0.96）可以分解成物种周转（丰富度没有变化的地点间的物种替代）和嵌套（物种贫乏地点是物种丰富地点子集时的物种差异）两个过程，其在该梯度上半段干旱生境和下半段浅水生境相对较高，且主要由周转过程控制。在常年积水生境上最低且仅由嵌套过程控制，而在环境梯度中间地段则由周转和嵌套过程共同控制；（3）物种丰富度和α多样性的主控因子沿该梯度发生了明显转换，在高水位区由水位、有机质和全磷共同控制；中水位区仅由速效磷控制；低水位区由pH和含水率控制。因此，松嫩平原半干旱区沿湖岸至高地环境梯度物种丰富度和α多样性存在明显的空间分布格局及具有较高的β多样性，且其主要形成机制为微地形创造局地空间环境异质性与物种库相互作用共同塑造了植物群落多样性，故在生物多样性管理实践中应对其空间分布格局完整性加以重点保护。 Abstract:Patterns and determinants of species richness are the central issues in ecology, but there is still a lack of consensus on their formation mechanisms. In order to explore the distribution patterns and determinants of community diversity along lakeshore-highland environmental gradient (local scale) in western Songnen Plain semi-arid region, species richness, α diversity, β diversity and environmental factors including water level (WL), soil water content (WC), organic matter (OM), etc. were measured by setting up sample belts and cluster analysis in seven communities (Typha angustifolia wetland, Typha minima wetland, Phragmites australis wetland, hassock wetland, Calamagrostis epigeios meadow, Leymus chinensis meadow and elm sparse forest) along this gradient, to reveal the spatial variation and formation mechanisms of community diversity. The results show that, along lakeshore-highland environmental gradient:(1) both species richness (2.00-18.00) and α diversity (Simpson index 0.12-0.90; Shannon-Wiener index 0.23-2.57 and Pielou index 0.34-0.88) showed a similar N-shaped distribution pattern (Typha angustifolia wetland was the lowest at the lower deep-water habitats, hassock wetland was the highest at the lower-middle seasonal inundated habitat, the lower at the middle-upper wet habitats of Calamagrostis epigeios meadow and the higher at the upper arid habitats of dune elm sparse forest). (2) We partitioned the generalized β diversity (Jaccard index 0.56-0.96) into two components:species turnover (species replacement among sites without changes in richness) and nestedness (species differences among sites when species-poor sites constitute subsets of those with a greater number of taxa). β diversity was relatively high at arid habitats located in upper half and shallow-water habitat located in lower half of the gradient, and it was mainly controlled by turnover processes. At the permanently inundated habitats, it was the lowest one, which is controlled only by nestedness processes. But in the middle of the environmental gradient, the turnover and nestedness processes control it togther. (3) The main controlling factors of species richness and α diversity were significantly converted along the gradient. The high water level area was jointly controlled by water level, organic matter and total phosphorus (TP), the medium water level area was controlled only by available phosphorus (AP) and the low water level area was jointly controlled by pH and water content. Therefore, there were obviously spatial distribution patterns of species richness and α diversity, and higher β diversity along lakeshore-highland environmental gradient in the Songnen Plain semi-arid region. Our results suggested that the main mechanism was the interaction between the local spatial environmental heterogeneity created by microtopography and the region species pool, which jointly shaped the plant community diversity. Thus, its spatial distribution patterns integrity should be protected in the practice of biodiversity management. 参考文献 相似文献 引证文献

Effect of nitrogen addition on the carbon metabolism of soil microorganisms in a Calamagrostis angustifolia wetland of the Sanjiang Plain, northeastern China

PurposeSoil microorganisms are important mediators of land ecosystem functions and stability. However, carbon sources in different amounts of nitrogen addition are known to affect the function of soil microbial communities. Thus, this study sought to evaluate the effects of nitrogen addition on the carbon utilization capacity of soil microorganisms in the Sanjiang Plain wetland, northeastern China.MethodsThree nitrogen treatments (CK, 0 kg N ha−1 a−1; N40, 40 kg N ha−1 a−1; and N80 kg N ha−1 a−1) were evaluated in the Honghe National Nature Reserve of the Sanjiang Plain. The carbon metabolism capacity of soil microorganisms in the C. angustifolia wetland was investigated after five consecutive year’s nitrogen addition treatment using the Bio-Eco technique.ResultsDifferent amounts of nitrogen addition conditions resulted in significant differences in pH, ammonium nitrogen (NH4+), dissolved organic carbon (DOC), and soil microbial alpha diversity. The average well-color development (AWCD) in the Bio-Eco Plate assay increased gradually with incubation time, and different nitrogen levels significantly affected these AWCD values (P < 0.05), with the N40 treatment exhibiting the highest value. Furthermore, the N80 treatment had significantly lower Shannon and Pielou diversity indices (P < 0.05). N40 significantly promoted carbohydrate, amino acid, and ester utilization rates by soil microorganisms, whereas N80 significantly inhibited carbohydrate, amino acid, alcohol, amine, and organic acids utilization. Redundancy analysis (RDA) showed that the three treatments had remarkable differences in soil microbial community metabolism, and the cumulative variance contribution was 72.86%. In addition, RDA revealed that the N80 treatment was positively correlated with the TN, SMC, DON, and TOC but negatively correlated with DOC, NH4+, pH, and NO3−.ConclusionLong-term nitrogen addition leads to changes in soil microbial community structure and significantly alters the ability of soil microorganisms to utilize carbon sources in the Calamagrostis angustifolia wetland.

Effects of simulated nitrogen deposition on the soil microbial community diversity of a Deyeuxia angustifolia wetland in the Sanjiang Plain, Northeastern China

PurposeThe soil microbial community is an important bioactive component of terrestrial ecosystems. Its structural and functional diversity directly affects carbon and nitrogen processes. This study aimed to investigate the variations in the diversity and composition of soil bacterial communities in a wetland with different nitrogen deposition conditions.MethodsA long-term simulated nitrogen deposition experiment was conducted in the Ecological Locating Research Station of the Institute of Nature and Ecology of Heilongjiang Academy of Sciences. Three different treatments were evaluated, including low nitrogen (LK; 40 kg N·hm-2·a-1), high nitrogen (HN; 80 kg N·hm-2·a-1), and control (CK; 0 kg N·hm-2·a-1). Bacterial 16S rDNA was then sequenced and analyzed using the next-generation sequencing technology.ResultHigher levels of N deposition resulted in an α-diversity increase followed by a decrease, with significant reductions in the HN treatment. Simulated nitrogen deposition resulted in changes in the structure and abundance of bacterial communities in wetland soils. The dominant phyla in all three plots were Proteobacteria and Acidobacteria. Compared with CK, the relative abundance of Chloroflexi increased significantly under the HN treatment (P < 0.05), whereas the relative abundance of Firmicutes and Bacteroidetes decreased significantly (P < 0.05). Nitrogen input changed the composition and relative abundance of the bacterial community, which was possibly due to N-induced soil acidification.ConclusionThis study thus provides a theoretical basis for predicting the effects of atmospheric nitrogen deposition on soil microorganisms, as well as changes in the wetland ecosystem in Sanjiang Plain.

Very fine roots contribute to improved soil water storage capacity in semi-arid wetlands in Northeast China

Wetland soil water storage affects the water cycle and maintains the stability of wetland ecosystems. Plant roots link soil and vegetation and play an important role in soil structure and function. However, our understanding of how roots control soil water storage in wetland ecosystems is relatively poor. This study compared and analyzed root traits and soil properties between different wetlands (Carex appendiculata, Calamagrostis angustifolia, and Phragmites australis) and bare land in the western Songnen Plain, Northeast China. We then comprehensively evaluated the soil water storage capacity under different vegetation types and identified the main root traits affecting soil water storage capacity. The results showed that different vegetation types presented different root distribution characteristics. Approximately 89.44%, 67.62%, and 82.67% of root biomass was distributed in the 0–20 cm soil layer in C. appendiculata, C. angustifolia, and P. australis wetlands, respectively. P. australis wetlands exhibited the lowest clay and silt contents, whereas the 0–40 cm soil layer exhibited the highest very fine sand, fine sand, and medium sand contents. C. angustifolia wetland showed the best soil water storage capacity, followed by C. appendiculata wetland, P. australis wetland, and bare land. Principal component analysis showed that the void ratio, bulk density, capillary porosity, organic matter content, medium sand content, silt content, very coarse sand content, and non-capillary porosity are major indicators for evaluating soil water storage capacity. Redundancy analysis showed that the volume of very fine roots is the most important root trait that affects the soil water storage capacity. This study provides practical guidelines for evaluating wetland ecosystem services and a theoretical basis for the restoration and reconstruction of degraded wetlands in semi-arid regions.

Response of Calamagrostis angustifolia to burn frequency and seasonality in the Sanjiang Plain wetlands (Northeast China)

Fire is an important disturbance in many wetlands, which are key carbon reservoirs at both regional and global scales. However, the effects of fire on wetland vegetation biomass and plant carbon dynamics are poorly understood. We carried out a burn experiment in a Calamagrostis angustifolia wetland in Sanjiang Plain (Northeast China), which is widespread wetland type in China and frequently exposed to fire. Using a series of replicated experimental annual burns over a three-year period (spring and autumn burns carried out one, two or three times over three consecutive years), together with a control unburned treatment, we assessed the effect of burn seasonality and frequency on aboveground biomass, stem density, and carbon content of aboveground plant parts and ground litter. We found that burning promoted plant growth and hence plant biomass in burned sites compared to the unburned control, with this effect being greatest after three consecutive burn years. Autumn burns promoted higher stem density and more total aboveground biomass than spring burns after three consecutive burn years. Burning increased stem density significantly, especially in twice and thrice burned plots, with stem densities in September over 2000 N/m2, which was much higher than in the control plots (987 ± 190 N/m2). Autumn burns had a larger effect than spring burns on total plant biomass and litter accumulated (e.g. 1236 ± 295 g/m2 after thrice autumn burns compared 796.2 ± 66.6 g/m2 after thrice spring burns), except after two burn treatments. With time since burning, total biomass loads increased in spring-burned plots, while autumn-burned plots showed the opposite trend, declining towards values found at unburned plots in year three. Our results suggest that, at short fire return intervals, autumn burns lead to a more pronounced increase in aboveground biomass and carbon accumulation than spring burns; however, the effects of spring burns on biomass and carbon accumulation are longer lasting than those observed for autumn burns.

Short-term effects of nitrogen deposition on nitrogen spatial and temporal distributions in a Calamagrostis angustifolia wetland of the Sanjiang Plain.

Nitrogen (N) availability is an important factor regulating the feedback mechanisms of global change. This research uses a small Calamagrostis angustifolia wetland i = on the Sanjiang Plain of Northeast China as the research object and 15N tracer technology to study the effects of different nitrogen deposition levels (0 gN/m2, 4 gN/m2, and 8 gN/m2) through in situ controlled field experiments. Temporal and spatial distribution patterns of nitrogen in plants and soils and their short-term effects on nitrous oxide emissions fluxes were studied. The results showed that 1) the nitrogen content in the stems, leaves and roots of C. angustifolia decreased slowly with the growing season. Nitrogen application significantly increased the absorption of tracer nitrogen in the aboveground and underground plant parts (P<0.01), and the more nitrogen applied, the larger the absorption amount was (P<0.01). The absorbed amount accounted for 52%-86% of the total tracer nitrogen. 2) The tracer nitrogen in the soil did not show a significant change; the more nitrogen that was applied, the more nitrogen that was retained in the soil, and the tracer nitrogen adsorbed by the soil was mainly ammonium nitrogen. 3) The variation in the 15N-labeled nitric oxide emissions flux under different nitrogen treatments was consistent; nitrogen application increased the 15N-labeled nitric oxide emissions flux, but the difference between the low-nitrogen and high-nitrogen treatments was not significant (P>0.05).

Short-term response of carbon emission to snow cover change in Calamagrostis angustifolia wetlands of Sanjiang Plain, Northeast China

To understand the response of Calamagrostis angustifolia wetland of the Sanjiang Plain to changes in snow cover, we examined the greenhouse gases emission flux of the removed snow treatment (0 cm, RS), the added snow treatment (50 cm, AS) and the control (20 cm, CK) of a C. angustifolia wetland, and their relations with environmental factors with the method of the static chamber-gas chromatography. The results showed that soil temperature, soil water content, and carbon emissions were lowest during the snow-covering period under all treatments, and gradually increased with time. With the increases of time and snow thickness, soil temperature was rised and the difference of three treatments gradually was decreased. Soil water content of RS was always lower than that of CK and AS. AS and CK could promote soil CO2 emission compared with RS during and after snowmelt. The soil cumulative CH4 emissions differed little among the treatments. There was significant correlation between soil temperature and cumulative CO2 and CH4 emissions. With the increases of soil temperature, soil cumulative CO2 emission continued to increase and soil cumulative CH4 emission decreased firstly and then increased rapidly. Soil water content was significantly correlated with cumulative CO2 and CH4 emissions. As the soil moisture increased, the cumulative soil CO2 emission gradually increased, reaching a certain threshold and then flattening, while soil cumulative CH4 emission continuously increased.

Effects of conversion from boreal natural wetlands to rice paddy fields on the dynamics of total dissolved iron during extreme precipitation events.

Natural wetlands play a critical role in increasing the total dissolved Fe (TDFe) concentration in boreal fluvial systems. In the Sanjiang Plain, which is the largest concentrated distribution area of natural wetlands in China, over 80% of the natural wetlands have been converted to rice paddy fields (RPFs) during the last six decades; the altered hydrological processes are hypothesized to influence the dynamics of TDFe, particularly during extreme precipitation events (EPEs). In the current study, the TDFe dynamics in typical natural freshwater wetlands in the Sanjiang Plain were elucidated. The TDFe species including Fe(II), Fe(III) and colloidal Fe, were monitored in a Deyeucia angustifolia wetland (DAW), Carex lasiocarpa wetland (CLW), and RPF during the rainy season from 2012 to 2014. Compared to normal precipitation days, the average TDFe concentration increased significantlys in all wetlands during the EPEs, among which the fluctuation of TDFe during the EPEs was more largely in the RPF than in the natural wetlands. The dynamics of the TDFe speciation in the different wetlands also showed different patterns; moreover, TDFe and its species showed a significantly positive relationship with dissolved organic matter. With an increasing frequency of EPEs anticipated by climate change models, our results suggest higher levels of TDFe will be transported to the Amur River and Okhotsk Sea, which may potentially affect TDFe cycling, water quality and ecosystem dynamics.

Response of soil C:N:P stoichiometry, organic carbon stock, and release to wetland grasslandification in Mu Us Desert

Wetlands in Mu Us Desert have severely been threatened by grasslandification over the past decades. Therefore, we studied the impacts of grasslandification on soil carbon (C):nitrogen (N):phosphorus (P) stoichiometry, soil organic carbon (SOC) stock, and release in wetland-grassland transitional zone in Mu Us Desert. From wetland to grassland, the transition zone was divided into five different successional stages according to plant communities and soil water conditions. At every stage, soil physical and chemical properties were determined and C:N:P ratios were calculated. SOC stock and soil respirations were also determined to assess soil carbon storage and release. After grasslandification, SOC contents of top soils (0–10 cm) decreased from 100.2 to 31.79 g kg−1 in June and from 103.7 to 32.5 g kg−1 in October; total nitrogen (TN) contents of top soils (0–10 cm) decreased from 3.65 to 1.85 g kg−1 in June and from 6.43 to 3.36 g kg−1 in October; and total phosphorus (TP) contents of top soils (0–10 cm) decreased from 179.4 to 117.4 mg kg−1 in June and from 368.6 to 227.8 mg kg−1 in October. From stages Typha angustifolia wetland (TAW) to Phalaris arundinacea L. (PAL), in the top soil (0–10 cm), C:N ratios decreased from 32.2 to 16.9 in June and from 19.0 to 11.8 in October; C:P ratios decreased from 1519.2 to 580.5 in June and from 19.0 to 11.8 in October; and N:P ratios decreased from 46.9 to 34.8 in June and changed from 34.9 to 34.0 in October. SOC stock decreased and soil respiration increased with grasslandification. The decrease of SOC, TN, and TP contents was attributed to the reduction of aboveground biomass and mineralization of SOM, and the decrease of soil C:N, C:P, and N:P ratios was mainly attributed to the faster decreasing speeds of SOC than TN and TP. The reduction of aboveground biomass and increased SOC release led by enhanced soil respiration were the main reasons of SOC stock decrease. Grasslandification led to lowers levels of SOC, TN, TP, and soil C:N, C:P, and N:P ratios. Grasslandification also led to higher SOC loss, and increased soil respiration was the main reason. Since it is difficult to restore grassland to original wetland, efficient practices should be conducted to reduce water drainage from wetland to prevent grasslandification.

Plant Diversity Performance After Natural Restoration in Reclaimed Deyeuxia angustifolia Wetland

Deyeuxia angustifolia wetlands were widely distributed in the Sanjiang Plain in Northeast China. Due to strong demand for food production, large-area wetlands were reclaimed to farmlands, which threatened regional ecological security greatly. Since the 21th century, returning farmlands to wetlands was widely adopted for natural restoration in the Sangjiang Plain. As the first reflection of wetland restoration, vegetation succession of restored D. angustifolia wetlands should be fully assessed. In this study, vegetation investigation was carried out in three restored D. angustifolia wetlands with 5, 8 and 12 yr restoration, respectively. Meanwhile, a natural D. angustifolia wetland was selected as reference wetland. Results showed that community composition changed greatly and there was visible community succession. Community dominant species changed from composite to gramineae as restoration time increasing. At first, weeds community appeared in the restored wetlands, especially the xerophytes developed to the pioneer species rapidly. And then, mesophytes and wetland species became the dominant species in the restored wetlands. Finally, wetland species, especially D. angustifolia, occupied the dominant position of restored community. Shannon-wiener index (H) and Simpson index (D) both decreased to close to natural D. angustifolia wetlands. Compared with natural D. angustifolia wetland, species composition and diversity in restored wetlands were more complex and higher. As restoration time increasing, there were not significant differences between community characteristics of restored wetlands and natural wetland. All these suggested that vegetation in reclaimed D. angustifolia wetland could be restored naturally, but its restored period is 10 yr at least. From another angle, it is important to protect current natural wetlands.

Effect of Freezing–Thawing Cycle on Soil Active Organic Carbon Fractions and Enzyme Activities in the Wetland of Sanjiang Plain, Northeast China

To determine the response of soil active organic carbon fractions and enzyme activities to freezing-thawing cycles (FTCs), an FTC simulation experiment of Deyeuxia angustifolia wetland soil samples collected from Sanjiang Plain, Northeast China, were examined. The results showed that the water-extracted organic carbon (WEOC), microbial biomass carbon (MBC) concentration and three enzyme activities were affected by FTCs. FTCs increased WEOC concentration, and the small amplitude (0 °C ± 5 °C) and the low water content interaction had the maximum impact, which was nearly 9.0–70.4%, while the large amplitude and the low water content interaction had the minimum impact, which was about 3.6–50.7%. FTCs significantly decreased MBC concentration, amylase, invertase and catalase activities. During the large amplitude (0 °C ± 10 °C) and high water content interaction impacted heavily on MBC, which was approximately 4.2–41.45%. As the number of FTC increased, WEOC concentration increased followed by a gradually decline in contrast that MBC concentration and three enzyme activities showed an opposite tendency. There was a significant correlation between soil active organic carbon fractions and enzyme activities. In addition, negative correlation was observed between WEOC and MBC. This may suggested that increased WEOC by FTCs plays an important role in soil microbes.

冻融作用对三江平原湿地土壤活性有机碳及酶活性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 冻融作用对三江平原湿地土壤活性有机碳及酶活性的影响 DOI: 10.5846/stxb201809121962 作者: 作者单位: 黑龙江省地理环境监测和寒区空间信息服务重点实验室,黑龙江省地理环境监测和寒区空间信息服务重点实验室,黑龙江省科学院自然与生态研究所;黑龙江省科学院自然与生态研究所,黑龙江省地理环境监测和寒区空间信息服务重点实验室,黑龙江省科学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技重大专项（2012ZX07201003-003）；"十三五"国家重点研发计划子课题（2016YFC0500405-03） Effects of freezing and thawing on soil active organic carbon and enzyme activity in the Sanjiang Plain wetlands Author: Affiliation: Key Laboratory of Remote Sensing Monitoring of Geographic Environment, College of Heilongjiang Province,,,,Heilongjiang Academy of Sciences Fund Project: National science and technology major project(No. 2012ZX07201003-003);The 13th five-year national key research and development planning projects (No. 2016YFC0500405-03) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了研究冻融作用对不同类型土壤活性有机碳组分及酶活性的影响，选取三江平原未受干扰小叶章湿地（UDAW），干扰小叶章湿地（DDAW）和水稻田（RP）土壤（0-10 cm，10-20 cm和20-30 cm）进行室内冻融模拟实验。实验设置（-10-10℃）和（-5-5℃）两个冻融幅度。将经过3次、6次、10次和15次冻融循环处理后的土壤活性有机碳和酶活性分别与未经过冻融处理的FTC（0）对比。结果表明：冻融循环增加了3种湿地土壤可溶性有机碳（Dissolved Organic Carbon，DOC）浓度。随着活动层深度的增加，同一类型土壤DOC增量降低，不同类型土壤DOC增量为UDAW最高，其次是DDAW，RP增量最低。与此相反，冻融循环均降低了土壤微生物量碳（Microbial Biomass Carbon，MBC）浓度和纤维素酶、蔗糖酶和淀粉酶的活性。随着土壤深度的增加，冻融循环对MBC和3种酶活性的影响逐渐减弱，不同类型间MBC浓度和3种酶活性降低幅度为UDAW高于DDAW，RP降低幅度最小。冻融幅度对DOC浓度的影响为-5-5℃大于-10-10℃，而对MBC浓度和3种酶活性的影响则是-10-10℃大于-5-5℃。冻融次数显著影响土壤活性有机碳组分（DOC与MBC）及3种酶活性（P < 0.05）。随着冻融次数的增加，DOC浓度先升高后降低，MBC浓度和3种酶活性则先降低后升高。此外，UDAW和DDAW土壤活性有机碳组分和土壤酶活性显著正相关（P < 0.01），暗示DOC浓度的增加，MBC起着重要作用。而在RP土壤中，二者的相关性降低，或许与人类的强烈干扰有关。 Abstract:The aim of this study was to analyze the influence of freezing-thawing cycles (FTCs) on soil active organic carbon fractions and soil enzyme activity in different types of soils. To this end, a laboratory freezing-thawing simulation test was carried out using soil samples from undisturbed Deyeuxia angustifolia wetlands (UDAW), disturbed Deyeuxia angustifolia wetlands (DDAW), and rice paddy fields (RP) in Sanjiang Plain. Soil samples were taken from different layers of each soil type (0-10 cm, 10-20 cm, and 20-30 cm). Two FTC amplitudes, namely, (-10-10℃) and (-5-5℃), were tested. Soil samples were then processed during the 3rd, 6th, 10th, and 15th FTCs, and dissolved organic carbon (DOC), microbial biomass carbon (MBC) and enzyme activity was compared in relation to FTCs (0). The results demonstrated that, in the three wetland soils, the dissolved DOC concentration increased after freezing-thawing cycles. The DOC concentration in each type of soil decreased with soil depth. DOC concentration increased the most in UDAW, followed by DDAW, and then RP. In contrast, MBC concentration and cellulase, sucrose and amylase activity in the soils decreased after freezing-thawing cycles. The effects of FTCs on MBC and the aforementioned activity of the three enzymes gradually weakened with increases in soil depth. MBC concentration and the three enzymes activities presented the greatest reduction in UDAW, followed by DDAW, and then RP. The effects of FTCs on DOC concentration in soils under a FTC amplitude of -5-5℃ were greater than that under a FTC amplitude of -10-10℃, but the opposite phenomenon was observed with respect to the effects of FTCs on MBC concentration and the three enzymes. The number of FTCs had a significant influence on the active organic carbon fractions (DOC and MBC) and the three enzymes activities (P < 0.05). With an increasing number of FTCs, the DOC concentration was first observed to increase and then decrease, whereas the MBC concentration and the activity of the three enzymes first decreased and then increased. In addition, soil active organic carbon fractions in UDAW and DDAW were significantly and positively correlated with soil enzyme activity (P < 0.01), which suggests that MBC contributes to the increased DOC concentration in soils. This correlation was weak in RP soils, which might be related to greater human disturbance in these types of soils. 参考文献 相似文献 引证文献

Responses of greenhouse gas emission to simulated nitrogen deposition in Calamagrostis angustifolia wetlands of Sanjiang Plain, China.

A long-term simulated nitrogen deposition experiment was carried out in Ecological Locating Research Station of the Institute of Nature and Ecology of Heilongjiang Academy of Sciences, with three different treatments including low nitrogen treatment (40 kg N·hm-2·a-1), high nitrogen treatment (80 kg N·hm-2·a-1) and the control (0 kg N·hm-2·a-1). The greenhouse gas emission fluxes were measured using a static box-gas chromatography method, with environmental factors being simultaneously investigated to understand the responses of greenhouse gas emission to the nitrogen deposition in the Calamagrostis angustifolia wetland. The results showed that low and high nitrogen treatments significantly increased the greenhouse gas emission fluxes. The CO2 emission flux increased by 47.5% and 47.9%, the CH4 emission fluxes increased by 76.8% and 110.1%, and the N2O emission fluxes increased by 42.4% and 10.6% in low nitrogen treatment and high nitrogen treatment, respectively. Low nitrogen input changed the seasonal dynamics of N2O emission fluxes but had no significant effect on that of CO2 and CH4 emissions. High nitrogen treatment did not affect the seasonal dynamics of greenhouse gas emissions. Soil temperature significantly positively correlated with CO2 and CH4 emission fluxes. There was no correlation between soil temperature and N2O emission flux because the factors affecting N2O emission were complex.

Variations in vegetative characteristics of Deyeuxia angustifolia wetlands following natural restoration in the Sanjiang Plain, China

Deyeuxia angustifolia wetlands widely distribute in the Sanjiang Plain in the northeastern China. Owing to land reclamation, these D. angustifolia wetland ecosystems are rapidly shrinking on the landscape, threatening ecosystem functioning and regional ecological security. Converting farmlands to wetlands serves as an ecological engineering widely used for natural restoration in Sangjiang Plain. Vegetation restoration process of restored D. angustifolia wetlands needs to be fully assessed. However, limited information is available for uncovering the impact of restoration time on ecological vegetative characteristics under natural succession. In this study, vegetation survey and sampling were carried out in six restored D. angustifolia wetlands with a chronosequence (2-, 4-, 8-, 13-, 16-, 20-year restoration), as well as the undisturbed D. angustifolia wetland. Plant community composition changed greatly during the past two decades. In the 2-year and 4-year restored wetlands, farmland weeds Artemisia argyi and Calamagrostis brachytricha were the dominant species. Plant communities were gradually dominated by D. angustifolia and Carex spp. with the increase of restoration time. Species diversity in restored wetlands was higher than that in undisturbed wetland and decreased with restoration time increasing. Plant height and coverage increased with the increase of the restoration time, whereas the plant density generally decreased. The plant communities in restored wetlands were increasingly close to that in the undisturbed wetland. The forb, sedge and grass plants accumulated more biomass in 2-year, 8-year and 20-year restored wetlands, respectively. Regression between the grass biomass and species diversity is significantly negative (p ≤ 0.05). Results in this study suggest that the vegetation of cultivated D. angustifolia wetland could be restored effectively through natural succession, although there were some functional differences between restored and undisturbed D. angustifolia wetlands. Community composition variance and functional traits based on vital attributes can be used to reliably predict changes in diversity of species in response to natural restoration.

Occurrence and distribution of phthalate esters (PAEs) in wetland sediments

This study investigated the occurrence and distribution of 15 phthalate esters (PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to 502.79 μg kg−1, with the mean value of 284.61 μg kg−1. PAEs significantly differed among wetland types; the average PAEs concentration of surface sediments were as follows: Phragmites australis wetland (PAW, 419.87 ± 73.61 μg kg−1) > Carex lasiocarpa wetland (CLW, 304.18 ± 56.47 μg kg−1) > Deyeuxia angustifolia wetland (DAW, 129.78 ± 18.24 μg kg−1). Dimethyl phthalate (DMP), diisobutyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate (DEHP) were found in all sediments, DEHP was the most abundant PAEs congeners with concentrations varying from 37.62 to 294.9 μg kg−1. DMP and DEHP exhibited relatively higher concentrations in CLW and PAW wetlands than in DAW, indicating that the different deoxidization and biodegradation conditions could have important implications for the distribution patterns of PAEs in wetland sediments. The variation of PAEs concentrations in horizontal and vertical sediments with wetland types could be attributed to the migration of contaminants by surface water, groundwater and atmospheric deposition. The occurrence and distribution of PAEs in wetlands also suggests that contamination in natural ecosystems should not be overlooked.

Fungal Community Structure of Different Degeneration Deyeuxia angustifolia Wetlands in Sanjiang Plain

To understand the wetland soil fungal community structure and diversity in different degeneration Deyeuxia angustifolia wetlands, the topsoil (0-20) of three different degeneration D. angustifolia wetlands were collected in the Sanjiang Plain field experiment station of the Institute of Nature and Ecology, Heilongjiang Academy of Sciences. The distribution and variation of soil fungal diversity were assessed by high-throughput sequencing method. The results showed that Shannon-Wiener index increased from marsh Deyeuxia angustifolia wetland marsh meadow Deyeuxia angustifolia wetland meadow Deyeuxia angustifolia wetland. Sequence blast showed that the fungal taxonomy belonged to Ascomycota, Basidiomycota, Chytridiomycota, Fungi_unclassified, Zygomycota, which dominant fungi were Fungi_unclassified (75.12%),Ascomycetes (56. 56%), Basidiomycetes (72.65%) in the three degeneration wetlands, respectively. The fungal structure compositions and diversities of marsh meadow Deyeuxia angustifolia wetland and meadow Deyeuxia angustifolia wetland were similar according to Heatmap analysis. The fungal community structure was influenced by soil nutrients (explained 88.62%) and plant composition (explained 9.85%) through the Variation partition analysis (VPA). In conclusion, the fungal community structure was significantly different, which was influenced by soil water content, in different degeneration Deyeuxia angustifolia wetlands in Sanjiang plain. The results may supply scientific basis for studying fungal diversity and spatial heterogeneity in degeneration wetlands.

Changes of soil labile organic carbon fractions and their relation to soil microbial characteristics in four typical wetlands of Sanjiang Plain, Northeast China

Soil labile organic carbon (LOC) fractions can response rapidly to environmental change and are essential to soil C cycling. There has been very little evaluation about the distribution differentiation of soil LOC factions in high-altitude wetlands. In this study, four typical wetland types were investigated in Sanjiang Plain of northeast China, including: (1) a mixed Calamagrostis angustifolia and Salix brachypoda (CSW), (2) Calamagrostis angustifolia wetland (CAW), (3) Carex lasiocarpa wetland (CLW) and (4) Phragmites australis wetland (PAW). The variation in soil LOC fractions of these wetland soils and their relationship with microbial characteristics were studied by analyzing the changes of dissolved organic carbon (DOC), microbial biomass carbon (MBC), easily oxidation carbon (EOC), soil microorganisms (bacteria, fungi, and actinomyces) and enzyme activities (invertase, cellulase and catalase). The results indicated that the contents of soil LOC fractions declined with increasing of soil depth in each wetland. At 0–30cm depth, the highest mean DOC content in seasonal flooded CAW, while the greatest average content of both MBC and EOC was in the drained CSW. The proportions of soil DOC, MBC and EOC to SOC account for 0.27–0.63%, 1.27–5.94% and 19.63–41.25%, respectively. Compared with two long-term flooded CLW and PAW, CAW and CSW showed higher soil LOC concentrations and proportions. In terms of soil microbial flora, bacteria number was the most, followed by actinomycetes and fungi number was the least in each wetland. The three microbial species populations decreased with soil depth in the four wetlands. The average microbial total amount was ranked in the order of CAW>PAW>CSW>CLW at 0–30cm depth. The higher soil activities of invertase, cellulase and catalase were observed in the surface soil layer for all wetlands. The three enzyme activities in CSW and CAW were significantly higher than that in CLW and PAW at 0–30cm depth. Soil LOC fractions were significantly related to SOC in the four wetlands (p<0.01), and positive correlation with microbial total number, bacteria, fungus and actinomyces in CSW and CAW (p<0.01). Whereas no significantly correlated were observed between LOC fractions and fungus or actinomyces in CLW and PAW. Except for catalase activity of CAW, soil LOC fractions had significantly correlation with three enzyme activities in the four wetlands (p<0.05). The results have important implications that microorganism and enzyme activities are good indicators for predicting minor changes of soil LOC fractions, especially in no-flooding CSW and CAW.

三江平原不同湿地类型土壤活性有机碳组分及含量差异

PDF HTML阅读 XML下载 导出引用 引用提醒 三江平原不同湿地类型土壤活性有机碳组分及含量差异 DOI: 10.5846/stxb201405060894 作者: 作者单位: 中国科学院东北地理与农业生态研究所,河南南阳师范学院生命科学与技术学院,中国科学院东北地理与农业生态研究所,中国科学院东北地理与农业生态研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院战略性先导科技专项课题(XDA05050508);国家自然科学基金项目(31100320,41171047)联合资助 Compositions and contents of active organic carbon in different wetland soils in Sanjiang Plain, Northeast China Author: Affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences,Department of Life Science and Technology, Nanyang Normal University, Henan province,Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences,Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤活性有机碳对土壤干扰的反应较快,是土壤有机碳早期变化的敏感性指标。近50年来,三江平原湿地土壤有机碳库受农事活动影响较大。为了探讨不同湿地类型土壤活性有机碳主要组分土壤可溶性有机碳(Dissolved organic carbon, DOC)、微生物量碳(Microbial biomass carbon, MBC)和易氧化有机碳(Easily oxidized organic carbon, EOC)的分布差异及主要影响因子,选择了三江平原洪河自然保护区4种典型的湿地类型(小叶章+沼柳湿地、小叶章湿地、毛苔草湿地和芦苇湿地)为研究对象。分析了不同湿地类型土壤可溶性有机碳,微生物量碳和易氧化有机碳在0-30 cm土层内的分布特征和分配比例及其与有机碳、土壤养分和酶活性指标(蔗糖酶、纤维素酶和过氧化氢酶)之间的相关关系。结果表明:(1) 4种湿地类型土壤DOC、MBC和EOC含量均随土层深度的增加而减少。不同湿地类型之间土壤活性有机碳含量在0-30 cm土层内存在显著性差异(P < 0.05),相对于长期淹水的毛苔草湿地和芦苇湿地而言,未淹水的小叶章+沼柳湿地和小叶章湿地具有较高的DOC,MBC和EOC含量。(2) 土壤DOC、MBC和EOC占有机碳比例分别为0.27%-0.63%,1.27%-5.94%和19.63%-41.25%。土壤DOC所占比例呈先增后减的变化趋势,最大的比例均出现在10-20 cm。MBC所占比例在土壤剖面上则未表现出一致的变化规律,而EOC所占比例则随土层深度的增加而逐渐减少。(3) 土壤DOC占SOC比例以小叶章湿地最高,MBC和EOC占SOC的比例则以小叶章+沼柳湿地最高。而长期淹水的毛苔草湿地和芦苇湿地则具有更低的DOC,MBC和EOC比例。(4) 综合分析表明,4种湿地类型土壤DOC, MBC 和EOC两两之间存在极显著相关性关系,它们除了与碳氮比相关性不显著外,与土壤有机碳,全氮,全磷养分和酶活性指标间相关性均达到极显著水平,尤其是与有机碳和全氮的相关性系数更高,此外DOC与纤维素酶,MBC与过氧化氢酶相关性更大。由此可见,土壤碳氮磷养分和酶活性是影响土壤活性有机碳组分分布的重要因素。 Abstract:Soil active organic carbon (AOC) fractions are good indicators of soil carbon stock change because of their rapid response to soil disturbances in natural ecosystems. Agricultural activities in the last 50 years have greatly influenced the soil organic carbon (SOC) of natural wetlands on Sanjiang Plain, China. The main objective of this study was to assess differences in the distribution of soil AOC fractions, including dissolved organic carbon (DOC), microbial biomass carbon (MBC), and easily oxidized organic carbon (EOC), and the main influencing factors in four different types of wetlands in the Honghe National Natural Reserve of Sanjiang Plain. The contents and allocation ratios of soil DOC, MBC, and EOC were investigated at three soil depths (0-10, 10-20, and 20-30 cm) in four types of wetlands: (1) a mixed Calamagrostis angustifolia and Salix brachypoda wetland (CSW), (2) a C. angustifolia wetland (CAW), (3) a Carex lasiocarpa wetland (CLW), and (4) a Phragmites australis wetland (PAW). The relationships among the three soil AOC fractions and soil nutrient contents (SOC, total nitrogen [TN], total phosphorus [TP]) and enzyme activity (sucrase, cellulase, and catalase) were also analyzed. The results showed that DOC, MBC, and EOC content gradually decreased with increasing soil depth in the 0-30 cm soil layer of all four wetlands. However, significant differences (P < 0.05) were noted for the soil AOC fractions among the four wetlands. The DOC, MBC, and EOC content was significantly higher in non-flooding CSW and CAW compared to long-term flooding CLW and PAW. In the four wetlands, the ratios of soil DOC, MBC, and EOC to SOC content at the three soil depths ranged from 0.27% to 0.63%, 1.27% to 5.94%, and 19.63% to 41.25%, respectively. In addition, the trend in the changes of soil DOC to SOC ratios initially increased, followed by a decrease along the soil profiles, with peak values being documented for the 10-20 cm soil layer. No specific trend was noted for MBC to SOC ratios, but EOC to SOC ratios decreased with soil depth. The highest DOC to SOC ratio was obtained for CAW, whereas the highest MBC and EOC to SOC ratios were obtained for CSW. In contrast, lower DOC, MBC, and EOC to SOC ratios were observed in the long-term flooding CLW and PAW. Furthermore, positive correlations were observed among DOC, MBC, and EOC in all four wetlands. Our results showed that DOC, MBC, and EOC content was strongly correlated with SOC, TN, and TP content as well as with the enzyme activity indicators in the four wetland soils, but no significant correlation was noted for the C/N ratio. A higher correlation coefficient was observed between these three AOC fractions with SOC and TN content. Furthermore, highly significant relationships were observed between DOC content and cellulase activity, as well as between MBC content and catalase activity. In conclusion, the soil AOC fractions were mainly influenced by soil nutrient content (SOC, TN, and TP) and enzyme activity, which are associated with the C cycle. 参考文献 相似文献 引证文献

Mercury distribution and accumulation in typical wetland ecosystems of Sanjiang Plain, Northeast China

Total mercury in soil, water, plant, insects, fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain, Northeast China. Results show that total mercury concentrations in soils of Deyeuxia angustifolia wetland and Carex lascarpa wetland are 0.046 mg/kg and 0.063 mg/kg, respectively. Total mercury concentration in water bodies is 0.053 μg/L on average. Of four plants studied, total mercury in moss is the highest with the mean of 0.132 mg/kg. Of 10 terrestrial insect species studied, total mercury in centipede (Scolopendra spp.) is the highest with the mean of 0.515 mg/kg while total mercury in grasshopper (Oxya spp.) bodies is the lowest. Total mercury concentrations in the herbivorous, omnivorous and predatory insects are 10.18 ng/g, 16.47 ng/g and 213.35 ng/g on average, respectively. Total mercury concentrations of the adult feather (549.88 ± 63.04 ng/g), nestling feather (55.15 ± 23.53 ng/g), and eggshell (22.05 ± 5.96 ng/g) of the Grey heron (Ardea cinerea) are higher than those of the Great egret (Egretta alba) (adult feather: 446.57 ± 90.89 ng/g; nestling feather: 32.99 ± 17.15 ng/g; eggshell: 21.02 ± 3.17 ng/g) in the wetlands of the Sanjiang Plain. The bioconcentration factors decrease in the order of piscivorous fish muscle > omnivorous fish muscle > herbivorous fish > insect.