Analysis on Landscape Pattern in the Upper and Middle Reaches of Yarlung Zangbo River:Taking Zhongba County,Angren County, Rikaze City as Example

Taking Zhongba County, Angren County, Rikaze City located at the Upper and Middle Reaches of Yarlung Zangbo River as landscape units , this paper studied the difference of the landscape pattern under various degrees of human disturbance in the three areas. The results showed that： the three areas all reflected the same characteristic of landscape pattern in Qinghai-Tibet Plateau, the natural landscapes were in the absolute dominant position. However, from Zhangba to Rikaze, with human disturbance intensity increasing, anthropogenic features of landscapes became more and more outstanding, In Zhongba, the landscape structure appeared to be simpler with coarse grains and a less rich diversity, Conversely, in Rikaze, the landscape showed a complicated shape with finer grains and a relatively richer diversity, This reflected that the impact of human activities to natural landscape behaved a gradually-growing trend from the upper reach to the middle one of Yarlung Zangbo River Basin.

Floristic Study of Vascular Plants in Typical Plant Communities in the Middle and Upper Reaches of the Yarlung Zangbo River

[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods] In the middle and upper reaches of the Yarlung Zangbo River,quadrat (line transect) method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]① There are 96 species (including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66% and 11.63%,2.02%,0.31% of total vascular plant families,genera and species in Tibet and China.② There are 24 monotypic-genus families,accounting for 68.57% of the total family number in the local area;22 monotypic-species families,accounting for 62.86% of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③ Local vascular plant genera fall into 10 areal types and 8 variations.④ Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤ There are 24 Chinese endemic species,accounting for 25% of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50% of endemic species to China,12.5% of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]① There are scarce plant groups in the local area.② Among the obvious advantages,single-genus (species) families possess the absolute advantage,and the flora has ancient origins.③ The local flora has diversified distribution types,and the complicated geographical elements.④ Temperate species possess obvious advantages,and the flora is young.⑤ Rich unique and rare species have high species diversity protection and research value.

Unsteadiness of COD in the Upper and Middle Reaches of Minjiang River

This paper explores and identifies the rules of the unsteady evolution of COD in the upper and middle reaches of Minjiang River through multi-scale analysis on the weekly COD data for the last six years provided by the Water Quality Monitoring Station,Minjiang River Bridge,Leshan City,Sichuan Province.The results of the wavelet analysis indicate that the COD index oscillates alternatively and differently at each time-scale in an oneyear cycle,and the density of COD,subjected to the runoff volume,the effects of Wenchuan Earthquake and agricultural seeding and industrial construction,etc.,is high in winter and spring,mild in summer and autumn.

The SIA method for spatial analysis of precipitation in the upper-middle reaches of the Yangtze River

Using geographic information system (GIS) techniques and the newest seasonal and annual average precipitation data of 679 meteorological stations from 1971 to 2000, the multiple regressions equations of the precipitation and topographical variables are established to extract the effect of topography on the annual and seasonal precipitation in the upper-middle reaches of the Yangtze River. Then, this paper uses a successive interpolation approach (SIA), which combines GIS techniques with the multiple regressions, to improve the accuracy of the spatial interpolation of annual and seasonal rainfall. The results are very satisfactory in the case of seasonal rainfall, with the relative error of 6.86%, the absolute error of 13.07 mm, the average coefficient of variation of 0.070, and the correlation coefficient of 0.9675; in the case of annual precipitation, with the relative error of 7.34%, the absolute error of 72.1 mm, the average coefficient of variation of 0.092, and the correlation coefficient of 0.9605. The analyses of annual mean precipitation show that the SIA calculation of 3-5 steps considerably improves the interpolation accuracy, decreasing the absolute error from 211.0 mm to 62.4 mm, the relative error from 20.74% to 5.97%, the coefficient of variation from 0.2312 to 0.0761, and increasing the correlation coefficient from 0.5467 to 0.9619. The SIA iterative results after 50 steps identically converge to the observed precipitation.

ANALYSIS OF THE MICROPHYSICAL STRUCTURE OF RADIATION FOG IN XUANEN MOUNTAINOUS REGION OF HUBEI,CHINA

Based on data of radiation fog events in Xuanen, Hubei province, 2010, this paper analyzes the microphysical process and evolution characteristics of radiation fogs with complicated substrate in the upper and middle reaches of the Yangtze River, and compares them with findings in other areas. Results are as follows: radiation fog in Xuanen is evidently weaker in droplet number concentration and liquid water content than land fogs in other areas. Its liquid water content fluctuates obviously, 0.01g/m3 with visibility of 1,000 meters, which is quite different from that in urban areas, but similar to the Nanling Mountains. Bi-modal droplet distribution is likely to occur in Xuanen mountain radiation fog(MRF) events. Statistical analysis shows that the observed droplet size distribution can be piecewise described well by the Gamma distribution. There is a positive correlation between liquid water content, fog droplet concentration and mean radius, especially in the development and dissipation stage. Condensation growth and droplet evaporation are major processes of Xuanen MRF. The dissipation time coincided with the time when the grass temperature reached the peak value, which indicated that dew evaporation is a key role in maintaining Xuanen MRF. In the early stage of dense fog's growth, droplets with diameter of over 20 micrometers can be observed with visibility of800-1,000 m, which might be caused by the transportation of low cloud droplets to earth's surface by turbulence. Big droplets in the initial stage correspond to higher water content, leading to the higher observed value of water content of Xuanen MRF.

长江中上游重要渔业水域环境质量评估

为准确评估长江中上游重要渔业水域水环境质量现状及变化趋势,提高水质评价效率,本研究基于11个水质参数,采用水质指数法(water quality index,WQI)对2006-2021年长江中上游三个重要渔业水域水质进行了综合评价,建立WQI min综合评价模型。结果显示:(1)长江中上游重要渔业水域的水温和高锰酸盐指数呈上升趋势;基于地表水环境质量标准(GB38338-2002),单因素水质评价结果表明监测水域内整体水质处于地表水Ⅴ类水标准,部分年份达劣Ⅴ类,主要污染指标为总氮。(2)通过综合评价方法分析,长江中上游重要渔业水域整体为“良”;2006~2021年长江中上游重要渔业水域水质质量呈逐年改善的趋势,且上游保护区的改善较大。(3)基于WQI方法,确定了长江中上游重要渔业水域的关键水质参数为:总氮、高锰酸盐指数、汞、溶解氧、氨氮、悬浮物以及水温,分别构建了上游保护区、中华鲟保护区以及四大家鱼保护区的WQI_(min)模型;考虑权重和不考虑权重的WQI min模型对比分析表明,考虑权重的WQI min模型的水质评价结果更加准确,该方法可有效评估长江中上游重要渔业水域的水质变化特征并可扩展用于其他水域。

雅鲁藏布江中游异齿裂腹鱼耳石日轮特征及繁殖期推算

研究以人工孵化的异齿裂腹鱼(Schizothorax o’connori)仔稚鱼为材料,验证了异齿裂腹鱼耳石轮纹沉积规律和第一日轮形成时间,建立了耳石轮纹数与日龄的关系,基于此对采集自雅鲁藏布江干流中游桑日县-加查县段的野生异齿裂腹鱼仔稚鱼的出膜时间进行了推算,并结合胚胎发育积温推算了亲鱼产卵时间。结果表明:人工养殖实验确定了异齿裂腹鱼孵化有效积温为2062.67℃·h,生物学零度为6.31℃;在水温6.8—8.8℃条件下,50%样本耳石第一轮纹在出膜后第1天形成(理论值为出膜后8.94h,n=439);微耳石和矢耳石轮纹数均与日龄呈线性相关,方程斜率均与1差异不显著(P>0.05),表明两对耳石的轮纹沉积均为日周期性,即仔稚鱼的日轮数为日龄。对野生异齿裂腹鱼仔稚鱼生长过程中耳石形态发育观察发现,微耳石的形态稳定,轮纹清晰,更适宜作为日轮计数材料。依据野生仔稚鱼样本微耳石日轮数,结合采样时间及耳石轮纹沉积规律等,推算出2022年野生仔稚鱼样本的孵化时间为3月11日至5月2日,结合孵化积温与实测平均水温,推算出其产卵时间为2月8日至4月23日。文章为研究异齿裂腹鱼自然种群资源保护与流域水电站生态调度等提供了科学依据。

雅鲁藏布江上游干、支流沉积物总有机碳分布特征初探

为探究雅鲁藏布江(雅江)上游干、支流沉积物总有机碳(TOC)含量分布特征及其影响因素,研究了雅鲁藏布江上游干、支流沉积物TOC含量对粒度的响应,并基于随机森林分析(RFA)解释了流域内土地利用类型对沉积物TOC含量空间变化趋势的影响。结果表明,雅江上游沉积物TOC含量均值[(6.56±6.37)g·kg^(-1)]低于其他地区大中型河流[范围为5.95~49.06 g·kg^(-1),均值为(19.77±14.05)g·kg^(-1)]。其中,河源段沉积物TOC含量均值最低[(2.57±0.97)g·kg^(-1)],所有采样点沉积物TOC含量与黏土含量占比呈极显著正相关(r=0.64,P<0.01)。根据统计结果,包括雅江上游在内,河流沉积物TOC含量与粒径小于63μm颗粒含量具有极显著指数相关关系(r=0.77,P<0.01)。随机森林分析进一步表明,雅江上游沉积物TOC陆源贡献率中草地贡献率最大(48.12%),且受土地利用方式从以低覆盖度草地、裸土地为主导(上游头段)逐渐过渡到以中、高覆盖度草地和农、牧、一类工业用地(M1类)等为主(上游中、末段)的影响,沉积物TOC含量在空间上表现为随流向逐渐增加的趋势。总体上,人为干扰因素少及河流沉积物以砂质为主体是雅江上游沉积物TOC含量较低的重要原因。本研究深化了对雅鲁藏布江上游沉积物总有机碳含量分布特征及其影响因素的理解,可为进一步探究高原河流碳循环、生态环境保护以及区域可持续发展提供科学依据。

雅鲁藏布江中游拉萨裸裂尻鱼环境DNA检测及生物量评估

建立快速和准确的环境DNA(eDNA)检测方法,可为鱼类的长期监测提供便利,为鱼类资源保护和管理提供技术支撑。2019年在雅鲁藏布江中游干流及拉鲁湿地和茶巴朗湿地采集了20种鱼和水样,针对拉萨裸裂尻鱼(Schizopygopsis younghusbandi younghusbandi)设计Cytb基因的特异性引物和探针,利用微滴式数字PCR(ddPCR)检测水样中e DNA拷贝数,并分析其与生物量和丰度之间的相关性。结果显示,正反向引物及探针序列与其他19种鱼之间的平均错配碱基数分别为6.8、6.9和3.6,且对其基因组DNA进行ddPCR扩增没有荧光信号。通过对比ddPCR和网捕2种方法,70%样点中检测结果相同,剩余30%样点都是网捕未捕获但ddPCR检出的情况。在拉鲁湿地和雅鲁藏布江干流的样点中,水样eDNA拷贝数与拉萨裸裂尻鱼生物量和丰度之间均具有显著的相关性,拉鲁湿地水样e DNA与二者的相关系数分别为0.987和0.647,雅鲁藏布江水样eDNA与二者的相关系数分别为0.786和0.756,表明eDNA技术是鱼类分布和生物量监测的有效方法。eDNA检测易受到近缘物种和水体理化性质的影响。

1951—2020年黄河上中游径流变化特征及归因分析

【目的】河川径流是地表重要的水资源,对其变化特征和原因进行解析,是流域水资源科学管理规划的前提。【方法】本文采用Mann-Kendall趋势检验、Pettitt突变检验、Budyko弹性系数法等方法分析了黄河上游和中游近70年(1951—2020年)径流变化的趋势和成因。【结果】(1)1951—2020年黄河上游年降水量呈不显著增加趋势(4.04 mm/(10 a),P> 0.05),中游呈不显著减少趋势(4.90 mm/(10 a),P> 0.05);上游、中游年潜在蒸散发均呈不显著增加趋势(1.77、2.23 mm/(10 a),P> 0.05);(2)黄河上游和中游1980—2020年土地利用/覆盖变化明显,主要表现在林草面积的增加,上游、中游年NDVI分别以0.025/(10 a)、0.042/(10 a)的速率显著增加(P <0.01);(3)1951—2020年,上游和中游年径流量分别以3.46、7.46 mm/(10 a)的速率显著减少(P <0.01),并分别在1986年、1990年发生突变;(4)上游和中游径流对降水变化最为敏感,其次是土地利用/覆盖变化、潜在蒸散发变化,且径流对各影响因子的敏感性逐年增强,即气候和土地利用/覆盖的变化将更容易引起径流的变化;(5)土地利用/覆盖变化是导致黄河上游和中游径流减少的主要原因,其次是降水和潜在蒸散,但各影响因子对径流变化的影响性质和程度在上游和中游不同区间存在一定的差异。其中,上游地区降水、潜在蒸散发、土地利用/覆盖变化对径流的影响性质和程度分别为-14.04%、1.30%、112.73%;中游地区分别为21.54%、3.63%、74.83%。【结论】1951—2020年黄河上游和中游径流变化是气候变化和土地利用/覆盖变化共同作用的结果,但主要影响因素为人类活动主导的土地利用/覆盖变化,且各因子对径流的影响在不同区间存在一定的差异。本研究结果可为黄河上游和中游不同区间的水资源管理和综合治理提供理论支持。

雅鲁藏布江中游不同生境大型土壤动物群落特征

为了解雅鲁藏布江中游地区不同生境的大型土壤动物群落特征,于2022年6月和9月进行了2次调查。选择农田、灌木丛、草地、人工林和天然林5种生境,并在每个生境中选择3个采样点作为重复。使用梅花五点法采集土样;采用手捡法和吸虫管法收集土壤表层的大型土壤动物样本,共捕获1 716只大型土壤动物,隶属于3门7纲22目48科。其中,蚁科(Formicidae)是优势类群,占总捕获量的15.97%。非参数检验(Kruskal-Wallis检验)结果显示,5个生境之间的多样性指数差异不显著(P>0.05)。Jaccard相似性系数(J)在0.35~0.73,表示5种不同生境的大型土壤动物群落在相似性程度上介于中等不相似到中等相似之间。置换多元方差分析(PERMANOVA)显示,5个生境群落结构之间存在显著差异(P<0.05)。在雅鲁藏布江中游地区的大型土壤动物功能类群中,以捕食性大型土壤动物为主,占总捕获量的43.13%。相关性分析显示,土壤pH值和全氮(TN)、有效磷(AP)及速效钾(RAK)含量是影响雅鲁藏布江中游大型土壤动物群落分布和多样性的重要因素(P<0.05)。

晚清长江中上游民船运输状况——以《长江三峡及重庆游记》为中心的考察

1883年英国商人立德乐通过实勘实测的方法记录了其在长江中上游流域乘坐民船的航行情况,并留下数万字的旅行记录——《长江三峡及重庆游记》,生动再现了晚清我国长江中上游流域传统民船的运输状况。通过对行记的考察可以厘清我国民船的运输情形,自从清代前期长江流域全面贯通以来,逐渐积累了成熟的造船技术、完善的民船运营结构、丰富的行船经验等,都促进了长江民船运输专业化,高效率水运系统的形成。与近代轮船运输相比,传统民船在运输价格、航行范围、运营的灵活性上都具有优势,即使在晚清长江中上游开通轮船运输后,民船运输仍在持续发展。

基于文献计量分析的长江中上游鱼类资源研究综述

针对长江中上游鱼类资源领域研究,以主题“长江上游”“长江中游”“金沙江下游”“鱼类资源”“鱼类早期资源”为检索条件,筛选了2023年7月前中国知网及Web of Science核心合集数据库收录的503篇文献,利用CiteSpace进行文献计量分析并绘制科学知识图谱,在此基础上从文献数量分布、研究机构及代表作者分布、研究主题内容、研究热点及演变趋势方面对长江中上游鱼类资源领域研究进行了综述。结果表明:中国科学院和中国水产科学研究院等是该领域的领军机构;从发展趋势上看,该领域已形成了鱼类资源现状及变化趋势、鱼类资源的影响机制以及鱼类资源的保护对策3个重要的研究热点和方向。后面需进一步完善江段鱼类资源的长期动态监测方法、梯级开发背景下鱼类资源的变动情况以及鱼类资源的协同保护方法等方面的研究。

韩江中上游地区的崩岗分布特征

选取韩江中上游地区2016—2022年的Sentinel-1/2卫星星座遥感影像和其他辅助数据,基于机器学习方法进行区域尺度的崩岗识别和崩岗影响因子测度。结果表明:1)分类模型的总体精度达到84%,Kappa系数为0.8。其中,崩岗识别的用户精度和生产者精度都超过95%,且其FScore为0.97。2)截至2022年,韩江中上游地区的崩岗侵蚀面积共有435.5 km^(2),各县(市、区)崩岗侵蚀面积差异明显,年变化趋势不一。其中,五华县崩岗侵蚀面积最多(199.2 km^(2)),其年平均变化率为16.29 km^(2)/a。梅江区崩岗侵蚀面积最少(1.6 km^(2)),其年平均变化率为0.18 km^(2)/a。3)韩江中上游地区崩岗发生概率与高程、坡度、植被覆盖、地质类型、人口密度、大气压、降雨量、经向风速、纬向风速和风速等10个因素存在显著相关性(P<0.001)。在一定的变化范围内,高程、坡度、地质类型、大气压、经向风速、纬向风速和风速对研究区崩岗发生为正向影响,植被覆盖、人口密度和降雨量对崩岗发生为负向影响。

淮河中上游地区新石器时代中期文化影响研究

淮河中、上游地区处于我国地理单元上的过渡中心,也是史前文化交流碰撞的“漩涡地带”。新石器时代中期两区域以淮河及其支流为纽带开启了文化上的互动交流,并逐步增强。两者之间的文化交流互动直接促进了淮系文化的形成与发展,并对淮河上游所在中原地区文化传播与扩散及早期中国各地考古学文化由分散、孤立走向交流、融合形成相对的文化共同体产生了积极的影响。

雅江中游河谷典型山水林田湖草沙生态修复工程技术实践

通过对雅鲁藏布江中游河谷典型山水林田湖草沙生态修复工程实施效果调查,针对露天采矿、灌草地退化、土壤沙化等突出生态环境问题,基于自然的解决方案,系统梳理并形成了地形地貌重塑、土壤基质重构、防沙治沙、植被恢复四大工程技术措施,对西藏山水林田湖草沙生态修复相关工程的实施具有一定借鉴和指导意义。

雅鲁藏布江上游径流变化及影响因素分析

雅鲁藏布江流域蕴藏着丰富的水资源,在气候变化背景下,近年来其上游(奴下水文站以上流域)的径流发生了显著变化。本文基于耦合冰冻圈过程的生态水文模型GBEHM,构建了雅鲁藏布江上游的分布式水文模型,对其水文过程进行模拟,计算得到上游水文要素的变化过程,并定量分析了气候变化对径流的影响。结果显示,1981—2010年雅江上游的年径流量和蒸散发量均呈显著增加趋势,降水增加是径流增加的主要因素;冰川和冻土发生显著退化,多年冻土面积占上游面积的比例减少约7%,多年冻土活动层厚度增加速率约30.6 cm/10a,季节性冻土的年最大冻结深度减少速率约7.3 cm/10a;流域冰储量以10亿m^(3)/a的速率显著下降,而冰川融化径流以2.7 mm/a的速率增加。

生态环境保护与农业经济高质量发展的协调性--以黄河中上游四省(区)为例

在构建生态环境保护与农业经济高质量发展评价指标的基础上,利用熵权法与耦合协调测度模型,考察黄河流域中上游四省(区)生态环境保护与农业经济高质量发展的协调性。研究结果表明,2010—2020年青海的协调性最高,其次是陕西,甘肃、宁夏分别处在该流域的第三、第四位,显然两个因素之间的协调性在黄河流域四省(区)从上游到中游在空间上呈现典型的“V”形分布。鉴于该流域各省(区)在生态环境保护与农业经济高质量发展之间的耦合度、协调度以及相对发展程度上存在明显差异,需要各地政府继续加大生态环境保护工程建设,加强农业绿色发展投资,从农业科技、环境监管、生态补偿等多方面加强区域协调发展,以期为该流域生态环境建设、农业经济高质量发展提供制度保障。

黄河上中游地区水‒粮食‒能源协同发展战略研究

黄河上中游地区是我国水资源、粮食、能源矛盾最为突出的区域之一,系统识别水‒粮食‒能源安全形势并提出应对措施,是该地区实现高质量发展的重要保障。本文在科学认识水‒粮食‒能源纽带关系基本内涵的基础上,研判了地区水资源、粮食、能源发展的新形势,剖析了水‒粮食‒能源协同发展面临的机遇和挑战,针对黄河流域生态保护和高质量发展目标,提出了新发展理念下水‒粮食‒能源协同安全的“四化一创”保障战略框架。研究建议,重视水资源在纽带关系中的核心作用,实现水资源支撑作用最大化;将能源作为区域高质量发展的战略性支柱产业,实现能源对经济社会发展带动作用最大化;强化农业用水支撑,实现粮食安全保障作用最大化;加强水资源保护,实现粮食、能源对水资源与生态环境干扰的最小化;加强基础科技研究,发展水‒粮食‒能源安全保障技术。