Sedimentary record of polycyclic aromatic hydrocarbons in Lake Erhai,Southwest China

The temporal distribution of polycyclic aromatic hydrocarbons （PAHs） was investigated in a sediment core from Lake Erhai in Southwest China using gas-chromatography/mass spectrometry （GC/MS） method. The total organic carbon （TOC） normalized total PAHs concentrations （sum of US Environmental Protection Agency proposed 16 priority PAHs） ranged from 31.9 to 269 ixg/g dry weight （dw）, and were characterized by a slowly increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments. The PAHs in the sediments were dominated by low molecular weight （LMW） PAHs, suggesting that the primary source of PAHs was low- and moderate temperature combustion processes. However, both the significant increase in high molecular weight （HMW） PAHs in the upper sediments and the vertical profile of diagnostic ratios pointed out a change in the sources of PAHs from low-temperature combustion to high-temperature combustion. The ecotoxicological assessment based on consensus-based sediment quality guidelines implied that potential adverse biological impacts were possible for benzo（ghi）perylenelene and most LMW PAHs. In addition, the total BaP equivalent quotient of seven carcinogenic polycyclic aromatic hydrocarbons （BaA, CHr, BbF, BkF, BaP, DBA and INP） was 106.1 rig/g, according to the toxic equivalency factors. Although there was no great biological impact associated with the HMW PAils, great attention should be paid to these PAH components based on their rapid increase in the upper sediments.

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.

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.

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.

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.

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.

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.

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

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。

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。

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。

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。

苍山洱海国家级自然保护区自然地理

苍山洱海国家级自然保护区管理局于2020年依托大理大学,对云南苍山洱海国家级自然保护区(以下简称“保护区”)开展为期2年半(2020年7月—2022年12月)的综合科学考察。其中,自然地理状况是科学考察的先导和基础。项目组采用文献资料收集整理、实地调查和“3S”技术等方法,梳理、分析了保护区的自然地理状况。项目成果为全面了解保护区的自然地理状况,合理保护和有效管理保护区的自然资源提供参考依据。

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。

洱海鱼类多样性

通过查阅20世纪50年代以来洱海鱼类相关文献资料,结合2022年洱海鱼类实地采样和走访调查,对洱海鱼类历史区系变化及现状进行分析。截至2022年,洱海共记录鱼类54种,分属于7目14科31属,其中土著种20种,特有土著种9种,国家二级保护动物1种:大理裂腹鱼Schizothorax taliensis。2022年洱海鱼类调查共发现鱼类23种,分属于4目9科,其中鲤科鱼类占鱼类物种总数的60.87%,其他鱼类占39.13%,包括鳅科、塘鳢科、鰕虎鱼科、鳢科、银鱼科、胡瓜鱼科、鲿科及鲇科,优势种为子陵吻鰕虎鱼Rhinogobius giurinus、■Hemiculter leucisculus、黄颡鱼Pelteobagrus fulvidraco和西太公鱼Hypomesus nipponensis;调查发现草金鱼Carassius auratus red var为洱海新记录物种。洱海鱼类群落组成表现为土著种种群数量减少,外来种逐渐增多,经济型鱼类和小型鱼类为当前优势种。

洱海流域典型农灌区地下水水文地球化学特征

洱海流域位于澜沧江、金沙江和元江三大水系分水岭地带,属澜沧江—湄公河水系。近年来,流域快速城镇化、农村生活方式改变、高强度种植业增加、环湖旅游业“井喷式”无序发展等因素导致洱海流域污染负荷快速增加(张浩霞,2020)。洱海流域污染主要来源于工业、城镇生活、农村生活、养殖业、农业面源、服务业、水土流失、干湿沉降等(张浩霞,2020)。

苍山洱海地区蚱总科昆虫(直翅目:蝗亚目)多样性

通过2020年9月—2023年9月对云南苍山洱海国家级自然保护区蚱总科昆虫进行调查,共获得蚱类昆虫3科12属24种。结合以往有关记录,目前已知云南苍山洱海国家级自然保护区蚱总科昆虫共计4科16属39种。

洱海水鸟多样性及种群时空格局

为了全面掌握洱海水鸟资源现状,2021年3月—2022年2月开展洱海水鸟调查。共记录到9目13科67种,其中古北种40种,广布种17种,东洋种10种;冬候鸟占比59.70%,留鸟占比13.43%,过境鸟占比13.43%,夏候鸟占比11.94%,迷鸟占比1.50%。2021年12月全湖最高记录到86000多只水鸟,其中骨顶鸡约64000只。洱海南部、西部和北部水鸟种类和数量居多,东部相对较少。全年记录到国家Ⅰ类保护水鸟3种,国家Ⅱ类保护水鸟7种,洱海水鸟多样性稳定向好转变。