Study on Environmental Risk and Economic Benefits of Rotation Systems in Farmland of Erhai Lake Basin

This study was designed to find out an optimised planting system of reducing non-point （source） pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.

Carnivals between Cangshan Mountain and Erhai Lake

THE Bai people are China’s 15th largest ethnic minority.They live mainly in Yunnan Province,specifically in Dali Bai Autonomous Prefecture,and some in Guizhou and Hunan provinces.Dali is where the Bai people’s ethnic roots are.From the 23rd to 25th day of the fourth lunar month every year,Bai people in Dali pray for

Seasonal dynamics of crustacean zooplankton community structure in Erhai Lake, a plateau lake, with reference to phytoplankton and environmental factors

The seasonal dynamics of a crustacean zooplankton community in Erhai Lake was investigated from May 2010 to April 2011. In total, 11 species were recorded, including six(6 genera) cladoceran and five(5 genera) copepod species. The crustacean zooplankton densities ranged from 24.3 to 155.4 ind./L. In winter and spring, the large-bodied cladoceran Daphnia galeata dominated the crustacean plankton community. In summer and autumn, when the colonial or filamentous algae dominated the phytoplankton communities, the small-bodied species(e.g. B osmina fatalis, Ceriodaphnia quadrangular, and Mesocyclops leuckarti) replaced the large-bodied ones. One-way ANOVA and redundancy analysis revealed that community structure was dependent upon total nitrogen, total phosphorus, water temperature, transparency, and the biomass of small algae. The variation in both phytoplankton structure and environmental variables were important factors in the seasonal succession of crustacean zooplankton structure in Erhai Lake.

Status and historical changes in the fish community in Erhai Lake

<Abstract>Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition,we evaluated the change in the community using historical data (1952-2010)describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected.0mnivorous and carnivorous species dominated the community. A canonical correspondence analysis (CCA) plot revealed that the distribution of fishes in the lake is influenced by aquatic plants,water temperature, pH, and season. The abundance of indigenous species hasdeclined sharply, and a majority of endemic species have been extirpated from the lake (adecrease from seven to two species). In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus,during the past20 years. Based on our results,wediscuss recommendations for the restoration and conservation of the fish resources in Erhai Lake.

RECENT SEDIMENTATION AND SUSPENDED MATTER IN ERHAI LAKE,YUNNAN PROVINCE,CHINA

Ths study on the physico-geograpical environment of Erhai Lake focused on the suspended matter and recent deposition rates, 14 C, 210 Pb and 137 Cs methods were used to determine the ageand sedimentation rate, which was found to be 0.5 t0 2.0 mm/a, average of 0.9 mm/a. The authors calculated the budget of some elements by studying the deposition, and fuUnd that about 30% of nitrogen,and most of the phosphorous, were transported into the lake by the ediments.

Ectoparasite communities on Tupaia belangeri (Scandentia:Tupaiidae) in surrounding areas of Erhai Lake in Yunnan,China

Objective:To investigate the ectoparasite communities on Tupaia belangeri (T. belangeri) in the surrounding areas of Erhai Lake and their potential importance in medical and veterinary science. Methods: Different locations in surrounding areas of Erhai Lake in Yunnan were selected as the investigation spots. T. belangeri were randomly captured with baited mouse cages and then brought to the laboratory for identification according to their body shape, size and color, and measurements such as the lengths of their body, ear and hind feet. Ectoparasites on them were collected and identified to determine the species under microscope after specimens were mounted on slides, with the clearing and drying process completed. The constituent ratio (C), prevalence (P) and average ectoparasite abundance (A) were used to test the prevalence and density of ectoparasites; Non-parametric Mann-Whitney U-tests were used to test the differences in the abundance and richness of ectoparasites between female and male hosts; Spearman correlation analysis was used to analyze the relationship between ectoparasites and the body parameters of hosts. Results: There was very high species diversity of ectoparasites found on T. belangeri and some species of ectoparasites were reported associated with human diseases. A high proportion (88%) of 107 T. belangeri was found to be infested with ectoparasites. A total of 75 species of ectoparasites on them were collected, including 58 species of chigger mite, 12 species of gamasid mite, 4 species of flea and 1 species of sucking louse. Within this ectoparasite complex, 13 species were previously reported to be vectors of human disease agents. Non-parametric Mann-Whitney U-tests showed significant differences between male and female T. belangeri in terms of the abundance and richness of total ectoparasites. However, the species richness and abundance of chigger mites, sucking lice, fleas or gamasid mites presented no significant differences between male and female hosts. Spearman correlation analysis showed that none of correlations were observed between host body parameters with abundance and richness of total ectoparasites, chigger mites, suckinglice, fleas or gamatid mites. Conclusion: The results suggest that there is very high species diversity of ectoparasites on T. belangeri, consisting mainly of communities of sucking lice, fleas, chiggers and gamasid mites.

A comprehensive evaluation method for plateau freshwater lakes:a case in the Erhai Lake

The study first systematically assessed the ecosystem health status of the plateau freshwater lake of Erhai Lake in Yunnan Province of China,using the revised Freshwater Health Indicator methodology,which comprised three components,i.e.,“Ecosystem Vitality,”“Ecosystem Services,”and“Governance and Stakeholders.”To better reflect the real health status of the basin,the cask short board effect was considered during aggregation of the indicators.In addition,analysis of the coupling coordination relationship among the three components was conducted to study the mutual influences among them as well as the comprehensive development level of the studied area.Basically,the ecosystem of the Erhai Lake basin remained healthy during the studied period according to the research due to specific measures and actions taken to manage the environmental problems caused by a former local economic development and urbanization process.However,there were still aspects to improve for more sustainable ecosystem management and utilization in the basin.The“short boards”of the Erhai Lake basin show room for improvement in local freshwater ecosystem management and underline governance problems that need to be addressed.Suggestions are provided for the local stakeholders consequently for the more sustainable development of the studied basin.

Eddy covariance measurements of water vapor and CO_2 fluxes above the Erhai Lake

Measurement of turbulence fluxes were performed over the Erhai Lake using eddy covariance(EC) method.Basic physical parameters in the lake-air interaction processes,such as surface albedo of the lake,aerodynamic roughness length,bulk transfer coefficients,etc.,were investigated using the EC data in 2012.The characteristics of turbulence fluxes over the lake including momentum flux,sensible heat flux,latent heat flux,and CO2 flux,and their controlling factors were analyzed.The total annual evaporation of the lake was also estimated based on the artificial neural network(ANN) gap-filling technique.Results showed that the total annual evaporation in 2012 was 1165 ± 15 mm,which was larger than the annual precipitation(818 mm).Local circulation between the lake and the surrounding land was found to be significant throughout the year due to the land-lake breeze or the mountain-valley breeze in this area.The prevailing winds of southeasterly and northwesterly were observed throughout the year.The sensible heat flux over this plateau lake usually had a few tens of W m-2,and generally became negative in the afternoon,indicating that heat was transferred from the lake to the atmosphere.The sensible heat flux was governed by the lake-air temperature difference and had its maximum in the early morning.The diurnal variation of the latent heat flux was controlled by vapor pressure deficit with a peak in the afternoon.The latent heat flux was dominant in the partition of available energy in daytime over this lake.The lake acted as a weak CO2 source to the atmosphere except for the midday of summer.Seasonal variations of surface albedo over the lake were related to the solar elevation angle and opacity of the water.Furthermore,compared with the observation data,the surface albedo estimated by CLM4-LISSS model was underestimated in winter and overestimated in summer.

Environmental evolution and southwest monsoon changes in mid-Holocene recorded by lake sediments in Erhai Lake

IN recent years, much progress has been made in the research of the temporal and spatial changes of East Asian monsoon. To research the environmental evolution and monsoon variations in Holocene in the region of Southwest China, a 310-cm continuous lake sediments core in Erhai Lake, Yunnan Province was sampled with Livingston sampler on July 6, 1996. The lake sediments were separated at 2-cm intervals and the core samples were analyzed with chronology, stable isotope ratios of organic carbon and diatoms determination. Three 14C ages are （4 473±40）a B.P. （98—102 cm）, （5 825±85） a B. P. （144—148 cm） and （7 754±45） a B.P. （198—202 cm）. By 137Cs dating, the sedimentation rate is about 0.3 mm/a and this result is close to the 14C dating results. The average sedimentation rates

Geochemical records of carbon in recent sediments of Erhai Lake, China: Implication of effects of the Himalayas uplift on global environmental changes

THE formation and uplift of the Himalayas and the Tibetan Plateau may have been responsible for the past150 Ma global environmental changes, resulting in the development of a three-tiered landform in southernChina. The Yunnan-Guizhou Plateau, as the middle tier in eastern slope of the Himalayas, has beencomplex environmental unit with great altitude gradients and plateau landform characters. Both monsoonsfrom the Pacific and the Indian resulting in apparent environmental changes on variable time scales influence it. Environmental geochemical effect of low latitude-high altitude could be yielded, and well recorded in the geological bodies in this region. To build and verify a quantitative model of environmental evolution it is necessary to obtain high-resolution data of elemental cycles and mass equilibrium.

Sediment Particle Size Distribution and Its Environmental Significance in Lake Erhai, Yunnan Province

A closed or semi\|closed plateau lake, whose sediment records can provide us with plenty of fine and high resolution information, is a sensitive indicator of climatic and environmental changes. During the reconstruction of various short\|time\|scale climatic and environmental changes, the geochemical records in plateau\|lake sediments are superior to other natural files. Based on fine dissection of the vertical profile of sediment particle sizes, this paper reveals the quasi\|periodical changes of sediment particle sizes, which indicates the quasi\|periodical fluctuations of the regional climate. A synthetic analysis of multiple indexes shows that sediment particle size is a more sensitive and more effective index of climatic and environmental changes than other geochemical indexes. High content of >20 μm sediment particles and low content of 2-10 μm sediment particles indicate a warm\|dry climate and conversely a cold\|humid climate, and their ratio can be used as an effective index of climatic changes. The basic climate succession in the region of Lake Erhai is characterized as being alternatively warm\|dry and cold\|humid and it has been developing into a warm\|dry climate as a whole. There exist at least 2 time\|scale quasi\|periodical fluctuations of the regional climate in Lake Erhai. At present, the region of Lake Erhai is at the end of the warm\|dry period and at the beginning of a cold\|humid period, so the temperature will go down and the water level will rise.

Climatic variations recorded by the sediments from Erhai Lake,Yunnan Province,southwest China during the past 8000 a

Erhai Lake is a large lake with important climatic significance in Yunnan Province, southwest China. The multi-proxy sedimentary records from Erhai Lake indicate the 9 stages of climatic changes with the alternation of warm-dry and cool-wet during the past 8000 a. The variations of Asian monsoon systems were the main cause for the climatic changes in southwest China. The warm-dry period was coincident with the intensification of India monsoon and Northwest Pacific Sub-tropical High Pressure, and the cool-wet corresponding to weak of India monsoon and its main rain belt moving back to southwest China.

High resolution environmental records in recent sediments of Erhai Lake, Yunnan Province

IN the past half a century, the global paleoclimate has been successfully reconstructed by natural recordssuch as ice core, loess and deep-sea sediments. However, these works mostly focused on long-timescale climatic changes. Along with the appearance of modern environmental problems including globalwarming, people are increasingly concerned about short-term climatic variations (annual to century scale)within the historical period. Therefore, it is an urgent and significant task for scientists to obtain continuous and high resolution natural records so as to reconstruct recent climatic changes truly and predict theclimate in the near future. As a main lodging of surface substances, the plateau-lake sediment continuously records the information of regional climate and environment with annual to decade resolution. Undoubtedly it is one

南诏国的两个地震神话

南诏国(738—902)有两个地震神话传世:一为观音大士镇伏巨鳌,令其长眠不醒,但允其七十至九十春可醒片时。巨鳌醒时眨眼,仍会地动山摇,以致每七十余年地震一次,每四百年大震一次。因此,在望海台树立地震碑,告诫后人要警惕震害。二为洱海河神段赤诚预报地震:今夜亥时,地将大动,十室九倒。为保民平安,遂与两位山神、河东渔夫分工合作:两山神分别变化为鸡与犬,狂鸣、惊跳,以警醒万民;河东渔夫向洱海东部村民报告,洱海河神变化为老叟向西部村民报告。十有九成的村民离开房舍,避于平坦之地,人畜皆安;不相信预报的百余人,皆遭震害。

降雨事件下洱海北部主要入湖河流污染物特征分析

通过研究2019年雨季(7—9月)洱海最主要的入湖河流污染物特征,对流域内6场次降雨下的污染物浓度与负荷进行监测,阐述6种污染物特征,计算入湖负荷,并评估对洱海的水质影响。结果表明:弥苴河是北三江流域径流与污染物入湖的主要贡献来源,径流量占北三江流域入湖总径流量的47%,氨氮、硝态氮、可溶性总氮(TDN)、正磷酸盐、可溶性总磷(TDP)和化学需氧量(COD)入湖负荷分别占总负荷的40.5%、65.0%、55.0%、55.0%、54.1%、57.1%;TDN、TDP、氨氮、COD污染负荷之间都存在着不同程度的相关性,降雨是影响氮磷等典型污染物负荷入湖的主要因素。雨季径流携带大量养分入湖使水体养分浓度升高,导致水体环境质量下降。因此在雨季控制径流携带污染物入湖,对防控洱海水质持续下降具有重要意义。

基于安德森模型的洱海流域小农户养老方式选择偏好及影响因素研究

为探索洱海流域小农户养老方式的选择偏好及影响因素,采用多阶段随机抽样方法抽取洱海流域40岁以上的村民290位,进行问卷调查获取数据;基于286份有效问卷运用卡方检验和二元Logistic回归,从40岁以上人员对养老相关问题的看法,分析小农户养老方式选择偏好的差异;以安德森行为模型为理论框架,探究倾向性因素、使能因素、需求性因素对洱海流域小农户养老方式选择偏好的影响。结果显示:洱海流域小农户目前以家庭养老作为主要的养老方式,倾向性因素是养老方式选择偏好最主要的影响因素,需求性因素次之。建议多方主体积极引导当地农户转变传统的养老观念,积极探索适合当地小农户的多元的养老方式,加大养老工作方面资金的投入力度。

洱海螺蛳(Margarya)历史演替及保护现状研究

螺蛳是中国特有种,曾经是云南高原湖泊的优势种群,由于人类活动、湖泊污染和过度捕捞等原因,目前仅在滇池、洱海、海西海、泸沽湖等湖泊分布。目前有三个属:螺蛳属(Margarya)、玺螺蛳属(Tchangmargarya)和环螺蛳属(Anularya)。文章详细介绍了螺蛳的分类、生活习性、食性、繁殖方式等基本生物特性,深入探讨了螺蛳在洱海的历史演替、增殖放流情况、保护现状及濒危原因,并据此提出了针对性的保育措施,包括建立高原湖泊软体动物人工繁育基地,进行珍稀濒危物种拯救行动计划,以及恢复野外种群,旨在为洱海本土螺蛳恢复提供科学依据,促进螺蛳及其他本土特有珍稀软体动物的保护和恢复。

典型挺水植物应用于湿地生态修复工程污染净化效应差异性研究

以洱海流域北部上游东湖片区库塘湿地中水生植物为研究对象,选取5种主要水生植物,寻求净化湿地水质的最佳植物组合。结果表明:东湖片区库塘湿地水体总磷、总氮、氨氮、化学需氧量分别为0.09~0.23、0.80~3.28、0.18~0.89、12.00~37.00 mg/L,总体符合《地表水环境质量标准》(GB 3838—2002)中Ⅳ类要求;综合比较发现,植物组合群落生物量和碳氮磷累积效应优于单一植物;植物组合对水体碳氮磷具有一定的吸收净化作用。

洱海流域土壤侵蚀强度时空变化及景观格局分析

采用改进的土壤流失方程(RUSLE)及热点分析研究了洱海流域2000—2020年的土壤侵蚀强度时空变化,并应用Fragstats软件从类型水平与景观水平分析土壤侵蚀影响下的景观格局变化趋势。结果表明:(1)20年间,年平均土壤侵蚀模数持续下降,微度侵蚀类型面积增加,而更强侵蚀类型的面积减少,说明洱海流域土壤侵蚀状况得到改善。(2)随着坡度增大,洱海流域年平均土壤侵蚀模数先增大后减小,在坡度为15°~25°时达到最大。(3)2000—2020年,洱海流域的景观格局也得到了优化。