长江经济带林地和其他生物质碳储量及碳汇量研究

以全国林业应对气候变化碳汇计量监测体系建设结果数据为基础,应用森林碳库专项调查建立的碳计量模型和参数,结合历次森林资源清查成果等数据,估算了2020年长江经济带林地和其他生物质碳储量和碳汇量。研究表明：（1）2020年长江经济带林地碳储量24543.58 Tg C （其中森林植被碳储量为4372.85Tg C）,散生木和四旁树等其他生物质碳储量329.59 Tg C。2020年长江经济带林地碳汇量81.81 Tg C/a （300.26Tg CO₂/a）、散生木和四旁树等其他生物质碳汇量6.60 Tg C/a （24.21 Tg CO₂/a）。无论是林地和其他生物质碳储量、碳汇量、还是森林植被碳储量,乔木林地所占比例最大（69%-85%）;长江经济带11个省市中,云南省最大,上海市最小;林地碳储量中土壤有机质碳库贡献最大（81.46%）,林地碳汇量中生物量碳库贡献最大（90.99%）;林地碳汇量中"一直为林地的土地"产生碳汇量贡献最大（71.74%）,其中一直为乔木林的土地产生的碳汇量占69.89%;（2）阐述了长江防护林工程、天然林资源保护工程、珠江防护林工程和沿海防护林工程4大重点生态工程对长江经济带碳储量和碳汇量的贡献,长江防护林工程贡献率最大（81%-83%）,其次是天然林资源保护工程（32%-38%）,珠江防护林工程和沿海防护林工程影响较小。分析了人工造林、中幼林抚育、次生林和低效林改造、退化林修复等生态保护修复措施对长江经济带碳储量和碳汇量的贡献,并提出了碳中和愿景下森林固碳增汇的有效途径。     

长江江豚和瓶鼻海豚的血清转铁蛋白

血清转铁蛋白(Serum transferrin,Tf)是广泛存在于血清中的β球蛋白,其主要功能是将铁离子以安全的形式(Fe3 )在机体的吸收、储存和利用部位之间进行传递,为细胞生长提供铁(Fe3 )(Welch,1990);同时具有保护细胞、促进细胞分化和生长、抑菌和杀菌的作用(Paezetal.,2002;Liuet al     

江豚表皮超微结构的研究

本文用透射电镜和扫描电镜对捕自莱州湾的两头江豚表皮的超微结构作了观察。见其表皮中MCG的板层结构与海豚的有所不同,MCG内容物排出到细胞间隙形成表皮屏障。其黑素颗粒可能通过黑素细胞的突起与角蛋白细胞相接触处胞膜的消失出现缺口的方式输入角蛋白细胞。并对江豚表皮的不全角化现象等问题进行了讨论。     

江豚的小肾结构指数和尿浓缩能力

对江豚的六项小肾结构指数的测定发现,黄海沿岸江豚的小肾结构指数明显高于长江江豚的。提示前者具有较高的尿浓缩能力。对尿的分析所获结论相同,反映出二者对所栖水域的不同渗透浓度的适应。     

Yangtze Dams Increasingly Threaten the Survival of the Chinese Sturgeon

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长江和畅洲江段大型船舶的噪声特征及其对长江江豚的潜在影响

长江航运业的快速发展导致长江中船舶数量激增,相应的水体噪声污染可能对同水域的长江江豚（Neophocaena asiaeorientalis asiaeorientalis）产生一定的负面影响,本研究采用宽频录音设备对长江和畅洲北汊非正式通航江段的各类常见大型船舶（长>15m且宽>5m）的航行噪声进行了记录,并分析其峰值-峰值声压级强度（SPLp-p）和功率谱密度（PSD）等。结果表明,大型船舶的航行噪声能量分布频率范围较广（>100kHz）,但主要集中于中低频（<10kHz）部分,各频率（20Hz~144kHz）处的均方根声压级（SPLrms）对环境背景噪声在该频率处的噪声增量范围为3.7~66.5dB。接收到的1/3倍频程声压级（TOL）在各频率处都大于70dB,在8~140kHz频段内都高于长江江豚的听觉阈值。说明大型船舶的航行噪声可能会对长江江豚个体间的声通讯及听觉带来不利影响,如听觉掩盖。     

扬子地台中部兰维恩至兰代洛世几丁虫生物地层

本文系统介绍了湖北宜昌普溪河、黔北遵义和四川酉阳丁市兰维恩世至兰代洛世地层中几丁虫的分布发育规律,指出扬子地台中部兰维恩世至兰代洛世的几丁虫自下而上可划分为Ｃｙａｔｈｏｃｈｉｔｉｎａｊｅｎｋｉｎｓｉ,Ｃｏｎｏｃｈｉｔｉｎａｃｏｎｕｌｕｓ,Ｅｉｓｅｎａｃｋｉｔｉｎａｕｔｅｒ和Ｌａｇｅｎｏｃｈｉｔｉｎａｄｅｕｎｆｆｉ等４个生物带,讨论了各几丁虫生物带的时代意义,此外还对几丁虫化石进行了图示和描述。     

长江上游干流及赤水河蛇鮈遗传多样性与种群历史分析

通过分析76尾来自长江上游干流宜宾(14尾)、合江(30尾)及支流赤水河(32尾)蛇(鮈)(Saurogobio dabryi)种群的线粒体细胞色素b(Cyt b)基因序列,研究蛇(鮈)3个地理种群的遗传多样性及种群历史.用于分析的Cyt b序列长1 097 bp,含变异位点28个,其中简约信息位点18个.76尾个体共检测到26个单倍型,整体呈现较高的单倍型多样性(Had=0.872)和较低的核苷酸多样性(Pi=0.004 0).三个种群共享较多的单倍型.基于单倍型构建的系统发育树及NETWORK网络关系图显示:所有来自长江上游干流和赤水河的单倍型不能按照地理分布各自聚类,而是相互混杂聚在一起;网络关系图呈星状分布,未检测到原始单倍型和进化中心.此外,基于单倍型频率分析得到的三个种群间的遗传分化指数FST值较低(分别为-0.0293、0.0280和0.0258).分子方差分析(AMOVA)显示,整体上长江上游干流及赤水河蛇(鮈)种群变异主要来源于种群内,种群内的变异占总变异的80.00％,表明长江上游干流及赤水河蛇(鮈)种群属于同一种群,蛇(鮈)各地理种群间基因交流频繁.中性检验、错配分析及BSP(Bayesian skyline plot)分析显示,整体上长江干流及赤水河蛇(鮈)种群在距今0～ 0.025 Ma(百万年)期间发生过种群扩张现象.     

Genetic variation and bidirectional gene flow in the riparian plant Miscanthus lutarioriparius,across its endemic range: implications for adaptive potential

Miscanthus lutarioriparius is an endemic species that grows along the middle and lower reaches of the Yangtze River and is a valuable source of germplasm for the development of second‐generation energy crops. The plant that propagates via seeds, stem nodes, and rhizomes shows high phenotypic variation and strong local adaptation. Here, we examined the magnitude and spatial distribution of genetic variation in M. lutarioriparius across its entire distributional range and tested underlying factors that shaped its genetic variation. Population genetic analyses were conducted on 644 individuals from 25 populations using 16 microsatellite markers. M. lutarioriparius exhibited a high level of genetic variation (H_E = 0.682–0.786; A_r = 4.74–8.06) and a low differentiation (F_ST = 0.063; D_est = 0.153). Of the total genetic variation, 10% was attributed to the differences among populations (df = 24, P < 0.0001), whereas 90% was attributed to the differences among individuals (df = 619, P ≤ 0.0001). Genetic diversity did not differ significantly across longitudes and did not increase in the populations growing downstream of the Yangtze River. However, significant associations were found between genetic differentiation and spatial distance. Six genetic discontinuities were identified, which mostly distributed among downstream populations. We conclude that anthropogenic factors and landscape features both contributed to shaping the pattern of gene flow in M. lutarioriparius, including long‐distance bidirectional dispersal. Our results explain the genetic basis of the high degree of adaptability in M. lutarioriparius and identify potential sources of new germplasm for the domestication of this potential second‐generation energy crop.     

Environmental flow assessment in estuaries taking into consideration species dispersal in fragmented potential habitats

Here, we propose an approach to environmental flow assessment that pays attention to species dispersal among fragmented potential habitat patches affected by river inflow and tidal currents in estuaries. The approach consists of three steps. In step one, potential suitable habitats were mapped and the Habitat Aggregation Index (HAI) was determined to understand the fragmentation of potential suitable habitats by integrating the requirements for critical environmental factors that have temporal and spatial variability. In the second step, an individual-based model was developed to simulate the dispersal of target species among potential habitat patches. The model provided the species distributions for altered hydrological processes. In the third step, environmental flows were defined by comparing the occupancy of suitable habitat patches by individual organisms and habitat aggregation for varying freshwater inflows. This approach was tested using a case study in the Yangtze River Estuary. We stressed the ecological importance of flood pulse, rather than average discharge, and recommend a Gaussian-type flood pulse, as provides a win–win point for both the numbers of individuals that could occupy suitable habitat and the HAI. We also demonstrated the importance of the peak flow and flood pulse duration in terms of affecting species distribution. Based on the results presented here, the proposed approach offers a flexible assessment of environmental flow for aquatic ecosystems.