三江并流地区干旱河谷植物物种多样性海拔梯度格局比较

在滇西北三江并流地区典型干旱河谷段, 在怒江、澜沧江和金沙江的东、西坡共设置了6条海拔梯度样带, 通过标准样地的植物群落调查, 分析各条样带植物的物种丰富度、物种更替率的海拔梯度格局, 并比较了地理和植被变量对分布格局的解释。干旱河谷植被带位于海拔3,000 m以下, 以灌丛和灌草丛为主, 其在各河谷的分布上限自西向东依次升高。植物物种丰富度的分布主要与海拔、流域、经纬度和植被带有关, 沿纬度和海拔梯度升高而显著增加的格局主要表现在草本层和灌木层, 灌木物种丰富度还呈现自西向东显著增加的趋势。怒江的灌木和草本种物种丰富度显著高于金沙江和澜沧江, 三条江的乔木种丰富度差异则不显著。森林带的样方草本物种丰富度显著低于灌草丛带样方, 并且还拥有后者没有的乔木种。不同样带的植物物种更替速率呈现了不一致的海拔梯度格局, 但均在样带海拔下部的灌草丛群落与海拔上部森林群落之间的交错带出现峰值。森林-灌草丛植被交错带在怒江样带处于海拔1,900-2,100 m处, 在澜沧江河谷位于海拔2,300-2,400 m, 在金沙江河谷位于海拔2,700-2,900 m。所有海拔样带的森林段或灌草丛段相对于同一样带不同植被段之间的物种更替程度为最小, 不仅小于同一流域不同样带相同植被段之间物种更替率的均值, 更小于所有样带相同植被段之间的更替率均值。在三条河流6条海拔样带的12个植被带段之间的物种更替变化中, 空间隔离因素可以解释34.2%, 而植被类型差异仅能解释不到0.5%。本研究结果显示了环境差异对不同植被类型物种丰富度的首要影响, 和各河流之间的空间隔离对植物群落构建和物种构成的主要作用。     

Effects of deep soil desiccation on artificial forestlands in different vegetation zones on the Loess Plateau of China

Deep soil desiccations are increasingly threatening artificial forests on the Loess Plateau of China. Soil moisture in 0–1000 cm soil layers of 23 kinds of tree and shrub forestlands was measured. Average soil moisture in 0–1000 cm soil profile of the forestlands was 10.84%, obviously lower than soil moisture in local natural grasslands and soil stable moisture. Average soil desic-cation intensity reached a medium level. Maximum soil water use depth was close to or over 1000 cm, and the thickness of desic-cated soil layers in forestlands reached or passed 800 cm.     

中国大陆自然保护地概况及分类体系构想

自1956年我国建立第一个自然保护区以来, 截至2016年底, 我国已建立了约10种类型且数量庞大的自然保护地。随着我国生态文明建设的不断发展,建立以国家公园为主体的自然保护地体系不仅是国家提出的重要任务,也是我国自然保护地未来发展的必然趋势。然而, 由于我国目前各类自然保护地尚无统一的分类体系, 已有的自然保护地之间存在着概念界定不清、分类体系混乱、主导功能模糊、地理空间重叠等诸多问题。这不仅严重阻碍了我国现有自然保护地的优化整合和国家公园体制建设,而且不便于开展国际交流。因此迫切需要明确自然保护地的定义, 建立一套适用于我国且有利于国际交流的自然保护地分类体系。本文在介绍自然保护地的概念与内涵,以及我国10类自然保护地建设和分类体系现状的基础上,重点梳理了我国自然保护地的发展历程, 比较了各类自然保护地的定义、内涵以及主要分类依据,并提出了3种能够涵盖目前各类自然保护地的分类体系构想,它们分别基于IUCN保护区分类系统、保护对象自然属性和管理目标社会属性。希望这些构想能在未来自然保护地分类体系的研究中起到抛砖引玉的作用。     

Seroprevalence of Toxoplasma gondii infection in Tibetan sheep in Tibet, China

In the present investigation, the seroprevalence of Toxoplasma gondii antibodies in 455 Tibetan sheep in Tibet, China, was examined using an indirect hemagglutination test. Of these, 26 (5.7%) Tibetan sheep were seropositive at the cut-off of 1:64 serum dilution. The seroprevalence ranged from 2.2% to 8.9% among Tibetan sheep of <1-yr-old, 1-3-yr-old, and >3-yr-old, but the differences among the age groups were not significant (P > 0.05). The prevalence in male Tibetan sheep (2.8%) was lower than that in female Tibetan sheep (6.6%), but the difference was not statistically significant (P > 0.05). The results of this survey indicated the presence of T. gondii infection in Tibetan sheep, which may cause economic losses to the local livestock industry and which poses a potential threat to human health in this area.     

雅鲁藏布江河岸植物物种丰富度分布格局及其环境解释

沿环境梯度物种多样性的分布格局及其环境影响因子的研究是生态学研究的重点内容之一。雅鲁藏布江是我国海拔最高的大河, 目前还没有针对其流域的河岸植物群落物种丰富度分布格局的系统研究。作者沿海拔梯度从雅鲁藏布江上游源头区至下游共设置了15个海拔样带, 在每个海拔样带随机取6个5 m×5 m样方, 共对90个样方的河岸植物群落物种组成和植被类型进行了调查, 共记录到238种维管束植物。DCA排序结果表明物种组成变化主要受海拔和经度控制。CCA排序区分出5种大的植被类型, 即高寒草甸或高寒草原、高山草原、两种亚高山灌丛草原和林缘灌丛植被。各植被类型的分布和变化主要受海拔和经度影响。雅鲁藏布江河岸植物物种丰富度沿海拔和经度梯度呈浅“U”形分布格局, 物种丰富度与年均降水量和植被盖度成显著正相关。     

大川河虎嘉鱼产卵场条件及其产卵习性的初步研究

虎嘉鱼(Hucho bleekeri Kimura)又名布氏哲罗鲑,系产于长江上游的稀有鱼类,分布极为狭窄,目前已确知的产卵场仅见于四川省芦山县大川河上游段。作者对其产卵场条件及产卵习性作了初步研究,目的为其增殖提供依据。       

地域环境对青藏高原特有植物藏川杨生物学特性的影响

通过对西藏中、南部16个藏川杨种源地环境特征、植株和枝叶形态特征、生长习性等生物学特性的观测比较,发现藏川杨为高大、长寿乔木,株龄逾千年、株高达45 m、冠幅22 m,分布海拔高度2000～4500 m、分布区域跨越湿润、半湿润、半干旱和干旱区,随着分布区环境变化,不同种源藏川杨的树皮、枝条、芽、叶等形态特征呈现规律性变化,空气湿度增加、树干颜色变深、枝条被毛加重、顶生冬芽变窄、叶片长/宽比增加;半湿润区和灌溉区植株的叶面积、枝条长度增加,湿润区、阴湿地或环境条件恶劣地区植株叶片和枝条生长不佳,枝条干湿比相对较小。结果表明:藏川杨具有很强的环境适应能力和可塑性,耐旱,喜光、抗强光辐射,耐贫瘠、喜中性或弱碱性土壤,具有很高的生态和经济价值。     

Phylogeography and allopatric divergence of cypress species (<Emphasis Type="Italic">Cupressus</Emphasis> L.) in the Qinghai-Tibetan Plateau and adjacent regions

Background  

Although allopatric speciation is viewed as the most common way in which species originate, allopatric divergence among a group of closely related species has rarely been examined at the population level through phylogeographic analysis. Here we report such a case study on eight putative cypress (Cupressus) species, which each have a mainly allopatric distribution in the Qinghai-Tibetan Plateau (QTP) and adjacent regions. The analysis involved sequencing three plastid DNA fragments (trnD-trnT, trnS-trnG and trnL-trnF) in 371 individuals sampled from populations at 66 localities.     

The urgent need to develop a new grassland map in China: based on the consistency and accuracy of ten land cover products

Grasslands are the most dominant terrestrial ecosystem in China, but few national grassland maps have been generated. The grassland resource map produced in the 1980s is widely used as background data, but it has not been updated for almost 40 years. Therefore, a reliable map depicting the current spatial distribution of grasslands across the country is urgently needed. In this study, we evaluated the grassland consistency and accuracy of ten land cover datasets (GLC2000, GlobCover, CCI-LC, MCD12Q1, CLUD, GlobeLand30, GLC-FCS30, CGLS-LC100, CLCD, and FROM-GLC) for 2000, 2010, and 2020 based on extensive fieldwork. We concluded that the area of these ten grassland products ranges from 107.80×10⁴ to 332.46×10⁴ km², with CLCD and MCD12Q1 having the highest area consistency. The spatial and sample consistency is highest in the regions of east-central Inner Mongolia, the Qinghai-Tibet Plateau and northern Xinjiang, while the distribution of southern grasslands is scattered and differs considerably among the ten products. MCD12Q1 is significantly more accurate than the other nine products, with an overall accuracy (OA) reaching 77.51% and a kappa coefficient of 0.51; CLCD is slightly less accurate than MCD12Q1 (OA=73.02%, kappa coefficient=0.45) and is more conducive to the fine monitoring and management of grassland because of its 30-meter resolution. The highest accuracy of grassland was found in the Inner Mongolia-Ningxia region and Qinghai-Tibet Plateau, while the accuracy was worst in the southeastern region. In the future grassland mapping, cartographers should improve the accuracy of the grassland distribution in South China and regions where grassland is confused with forest, cropland and bare land. We specify the availability of valuable data in existing land cover datasets for China’s grasslands and call for researchers and the government to actively produce a new generation of grassland maps.

     

大川河鱼类区系及其群落生态结构的研究

鱼类区系及其群落生态结构,在理论和实践上都有十分重要的意义。但是,关于鱼类区系的生态结构问题,还未见详细报道。本文通过对大川河鱼类区系及其群落生态结构的分析,探讨鱼类区系及其群落生态结构的规律。