青藏高原不同海拔3种菊科植物叶片结构变化及其生态适应性

采用常规石蜡制片技术和显微观察方法,对分布于青藏高原祁连山东部山地冷龙岭3600—4400 m不同海拔高度的蒲公英(Taraxacum mongolicum Hand-Mazz)、火绒草(Leontopodium leontopodioides(Willd.)Beauv)和美丽风毛菊(Saussurea superba Anthony)的叶片形态解剖结构进行了研究,并探讨了其对海拔高度的响应及生态适应性。结果表明:随海拔高度的升高,3种植物气孔器外拱盖内缘、角质层纹饰、气孔与表皮细胞的位置关系以及上、下表皮气孔器内缘呈现不同的变化趋势;火绒草上、下表皮气孔密度随海拔升高而增加,而蒲公英和美丽风毛菊的气孔密度则降低;3种植物上、下表皮气孔指数随海拔高度的增加均未出现规律性变化;3种植物叶片厚度、上下表皮厚度、上下角质层厚度、栅栏细胞系数均随海拔升高而增加;解剖学指标之间大多呈明显的协同进化;叶片结构,尤其是气孔密度对海拔高度变化表现出较大的可塑性。研究表明3种植物采取不同的响应机制来适应海拔高度的变化,植物对高原环境变化的适应具有多样性。     

西藏列当科新记录属——豆列当属

在西藏八宿县然乌镇安久拉山垭口进行植物多样性调查时,发现一种寄生植物,经过查阅文献、核对模式标本,最终鉴定为列当科(Orobanchaceae)豆列当属(Mannagettaea)植物矮生豆列当(Mannagettaea hummelii H. Smith)。该种分布在中国及俄罗斯(萨彦岭地区),国内记载仅分布在甘肃、青海、四川;西藏为新记录属。该发现丰富了西藏的植物区系,同时将矮生豆列当分布海拔提升至4 459 m。凭证标本现存于中国科学院昆明植物研究所标本馆(KUN)。     

Length–weight and length–length relationships of four native fish species of the Qinghai‐Tibet Plateau,China

This study presents the length–weight (LWR) and length–length relationships (LLR) of four fish species (Gymnocypris namensis Wu & Ren, 1982; Herzensteinia microcephalus Herzenstein, 1891; Triplophysa stenura Herzenstein, 1888; and Triplophysa brevicauda Herzenstein, 1888) collected from the Qinghai‐Tibet Plateau, China. A total of 291 specimens was collected using electric fishing (12V), gill nets (mesh size: 2 × 2 cm, 3 × 3 cm) and cast nets (mesh size: 2 × 2 cm), in July 1998 and October 2014.     

海拔高度对青藏高原放牧牦牛肠道菌群多样性的影响

[背景]肠道菌群与宿主健康及环境适应性密切相关,牦牛为青藏高原特有的草食性反刍动物,不同海拔高度如何影响牦牛肠道菌群组成及肠道菌群在牦牛适应高海拔生境中的作用尚不清楚.[目的]探究青藏高原放牧牦牛肠道菌群多样性及其与海拔高度间的关系.[方法]采集青海省玛沁县(海拔4220 m)和乐都县(2745 m)2个海拔高度放牧牦...     

青藏高原植被生态系统垂直分布变化的情景模拟

如何模拟和揭示青藏高原植被生态系统垂直分布在全球气候变化驱动下的时空变化情景,对定量解析青藏高原陆地生态系统对气候变化响应效应具有重要意义。该论文基于Holdridge life zone （HLZ）模型,结合数字高程模型（DEM）数据,改变模型输入参数模式,发展了改进型HLZ生态系统模型。结合1981-2010（T0）时段的气候观测数据和IPCC CMIP5 RCP2.6、RCP4.5、RCP8.5三种情景2011-2040（T1）、2041-2070（T2）、2071-2100（T3）三个时段气候情景数据,实现了青藏高原植被生态系统垂直分布的时空变化情景模拟。引入生态系统平均中心时空偏移趋势模型和生态多样性指数模型,定量揭示了青藏高原植被生态系统在不同垂直带上的时空变化情景。结果显示：青藏高原共有16种植被生态系统类型;冰雪/冰原、高山潮湿苔原和亚高山湿润森林为青藏高原主要的植被生态系统类型,其面积之和占到了青藏高原总面积的56.26%;高山干苔原、亚高山潮湿森林、山地灌丛、山地湿润森林和荒漠等对气候变化的敏感性总体上高于其它类型;在T0-T3期间,青藏高原的高山湿润苔原、高山干苔原、荒漠呈持续减少趋势,平均每10年将分别减少1.96×10⁴km²、0.15×10⁴km²和1.58×10⁴km²;亚高山潮湿森林、山地湿润森林和山地灌丛呈持续增加趋势,平均每10年将分别增加3.42×10⁴km²、2.98×10⁴km²和1.19×10⁴km²;RCP8.5情景下青藏高原的植被生态系统平均中心的偏移幅度最大,RCP4.5情景下的偏移幅度次之,而RCP2.6情景下的偏移幅度最小。另外,在三种气候变化情景驱动下,青藏高原植被生态系统的生态多样性呈减少趋势。总之,未来不同情景的气候变化将直接影响青藏高原植被生态系统的时空分布格局及其生态多样性,气候变化强度越高,影响就越大,而且气候变化对青藏高原植被生态系统的影响呈现出从低海拔到高海拔递增的影响效应。     

Length‐weight relationships for nine fishes in the Nujiang River,Southwest of China

Length‐weight relationships (LWRs) were determined for nine fish species occurring in the Nujiang River. Fish were collected using gill nets, including two nets of 1.0 m depth (100 m long; mesh size 0.5 cm), two nets of 1.0 m depth (150 m long; mesh size 2.0 cm) and two nets reaching 1.5 m depth (mesh size 6.0 cm). Gill nets were set over night including different habitats (riffles and pools, vegetated and non vegetated zones) from four sections in July of the following 2 years: 2004 and 2008. The LWRs presented here include for all nine studied species (Pseudexostoma brachysoma Chu, 1979, Creteuchiloglanis gongshanensis [Chu, 1981], Glyptothorax zanaensis Wu, He & Chu, 1981, Glyptothorax dorsalis Vinciguerra, 1890, and Glyptothorax trilineatus Blyth, 1860, Schizothorax gongshanensis Tsao, 1964, Schizothorax meridionalis Tsao, 1964, Placocheilus cryptonemus Cui & Li, 1984, and Schistura longa [Zhu, 1982]), and new maximum standard length of four species not yet reported in the literature.     

Variation in seed germination between populations of five sub-alpine woody species from eastern Qinghai-Tibet Plateau following dry storage at low temperatures

Effects of cold-dry storage on dormancy break and viability were determined for seeds of the five sub-alpine woody species Philadelphus incanus, Berberis vernae, Berberis dubia, Betula utilis, and Picea purpurea collected along an altitudinal gradient on the eastern part of the Qinghai-Tibet Plateau in China. Germination tests were conducted at 20/5°C for seeds stored dry at ambient room temperature for 4 weeks and then at 3–4°C for 0, 6, 12, and 24 weeks. Dormancy break during dry storage, i.e., afterripening, was indicated by an increase in germination percentages and rates. Duration of cold-dry storage and altitude of seed collection had significant effects on germination. With an increase in duration of storage, germination percentages and rates of P. incanus and B. vernae increased with a decrease in altitude of seed collection, while they increased with an increase in altitude for seeds of B. utilis and P. purpurea. Seeds of B. dubia did not exhibit changes in germination percentages and rates with altitude because a high number of seeds remained dormant during storage. Seed viability after 24 weeks of storage ranged from high (88, 93.3, 92.7%) for B. utilis to low (15% for high altitude) for P. incanus. The potential for dormancy break to occur during cold-dry storage should be considered when studies on basic seed dormancy are conducted or when seeds from various locations are stored prior to propagating plants from them.     

C4 Plants in the Vegetation of Tibet,China: Their Natural Occurrence and Altitude Distribution Pattern

Floristic composition, life forms for C₄ species, and the pattern of altitude distribution were studied on Tibetan Plateau. 79 species, in 7 families and 46 genera, were identified with C₄ photosynthesis. 95 % of these C₄ species belong to Gramineae (51 species), Cyperaceae (14 species), and Chenopodiaceae (10 species), indicating that C₄ plants mainly occur in very few families (7 of 204) on the Tibetan Plateau. High altitude distribution for all the Chenopodiaceae C₄ species (> 3 000 m above sea level) suggests that plants of this kind have large tolerance to cold, dryness, and strong ultraviolet radiation. Most Gramineae and Cyperaceae C₄ species occurrences are consistent with extensive distribution of steppes and meadows in the vast flat of the central Plateau (1 000–3 000 m a.s.l.). Relatively high amount of hemicryptophyte form plants (44 %) in the region indicates that the vegetation, especially grassland, meadows, and steppe, are in good condition. There is a strong relationship between numbers of C₄ species and altitude in the Tibetan Plateau. Occurrence of C₄ species is significantly less in both high and low altitude plateaux in Tibet. Altitude distribution pattern for C₄ species in the region is not only consistent with the altitude and climate, but also with the vegetation types in altitude gradient.     

Origins of the Greenland shark (Somniosus microcephalus): Impacts of ice‐olation and introgression

Herein, we use genetic data from 277 sleeper sharks to perform coalescent‐based modeling to test the hypothesis of early Quaternary emergence of the Greenland shark (Somniosus microcephalus) from ancestral sleeper sharks in the Canadian Arctic‐Subarctic region. Our results show that morphologically cryptic somniosids S. microcephalus and Somniosus pacificus can be genetically distinguished using combined mitochondrial and nuclear DNA markers. Our data confirm the presence of genetically admixed individuals in the Canadian Arctic and sub‐Arctic, and temperate Eastern Atlantic regions, suggesting introgressive hybridization upon secondary contact following the initial species divergence. Conservative substitution rates fitted to an Isolation with Migration (IM) model indicate a likely species divergence time of 2.34 Ma, using the mitochondrial sequence DNA, which in conjunction with the geographic distribution of admixtures and Pacific signatures likely indicates speciation associated with processes other than the closing of the Isthmus of Panama. This time span coincides with further planetary cooling in the early Quaternary period followed by the onset of oscillating glacial‐interglacial cycles. We propose that the initial S. microcephalus–S. pacificus split, and subsequent hybridization events, were likely associated with the onset of Pleistocene glacial oscillations, whereby fluctuating sea levels constrained connectivity among Arctic oceanic basins, Arctic marginal seas, and the North Atlantic Ocean. Our data demonstrates support for the evolutionary consequences of oscillatory vicariance via transient oceanic isolation with subsequent secondary contact associated with fluctuating sea levels throughout the Quaternary period—which may serve as a model for the origins of Arctic marine fauna on a broad taxonomic scale.     

青藏高原土地利用变化对生态系统服务价值影响的多情景模拟

青藏高原具有突出的生态服务价值,但气候多变、环境脆弱的基底,使其易受人类活动的干扰。本文基于土地利用数据和改进当量因子法,定量分析1992—2015年青藏高原土地利用变化对生态系统服务价值时空分布影响,并结合CA-Markov模型模拟探讨自然发展和生态保护情景下土地利用与生态系统服务价值的相互关系。结果表明:1992—2015年青藏高原土地利用结构稳定,以草地为主,林地、裸地为辅,生态系统服务价值总体呈增长趋势,草地、水体和林地是青藏高原生态价值的稳定供应者;青藏高原生态系统服务价值的空间分布极不均衡,不同气候区分布具有空间异质性,冷点区集中分布在青藏高原西北部干旱气候区和东南部湿润气候区,热点区集中于中部湿润和半湿润气候区;6000 m海拔是青藏高原生态系统服务价值的趋势变化节点;生态保护情景下的土地利用变化比自然发展情景下的更加均衡,生态系统服务价值总体增加,生态环境向优发展。     

Characterisation of high-altitude Artemia populations from the Qinghai-Tibet Plateau,PR China

The brine shrimp Artemia was discovered in a number of saline lakes on the Qinghai-Tibet Plateau, widely diverging in chemical composition. Several lakes were athalassohaline, with relatively high amounts of trace elements. Common environmental factors are their high altitude (exceeding 4500 m) and the low average annual temperatures. A number of Artemia populations in this area were analysed to assess their preference for low temperatures and an athalassohaline medium. Furthermore, their characteristics were compared with Artemia tibetiana, the species recently described for one lake in this area. All samples contained a variable mixture of parthenogenetic and bisexual individuals. A cross-breeding test of the sample from Jingyu Lake showed cross-fertility both with A. tibetiana and A. sinica. All populations showed similarities to A. tibetiana: a large cyst diameter and naupliar length, high HUFA content and a high tolerance to low temperatures, as compared to the control A. franciscana samples. These can thus be considered as recurrent characteristics of the populations from the high-altitude low-temperature environment on the Qinghai-Tibet Plateau, although further research is needed to identify their exact species status.     

Diversity of terrestrial isopod species in the Chambi National Park (Kasserine,Tunisia)

Diversity of terrestrial isopods across habitats and altitude was studied in the National Park of Chambi (central Tunisia). Samples were collected over five years in seven sites (S1–S7), within an altitudinal range from 750 to 1,500 m a.s.l. Twelve species belonging to five families were identified, with one endemic species (Porcellio djahizi) to this area, and three species were present in all sites (P. djahizi, Leptotrichus panzerii and Armadillidium tunisiense). Agnaridae represented by Hemilepistus reaumurii species was the most abundant family (58.77%) and found in only one site. Our results showed differences in species richness between sites. Indeed, S2 and S3 (900 and 1,050 m) showed the highest species richness with 11 species each. This result validates the hypothesis of mid‐elevational richness peak and contradicts the theory of large sampling regimes in determining the relationship between species richness and elevation. Terrestrial isopod species richness in the Chambi Mountain tends to decrease with altitude: 11 species in S2 and S3 to four species in S7. The highest Shannon–Wiener diversity index value was observed in S2 (H′ = 3.21 bits). Canonical correspondence analysis revealed that H. reaumurii was positively correlated with temperature whereas A. tunisiense and P. djahizi were the only species positively correlated with altitude.     

Chironomidae (Diptera) larvae assemblages differ along an altitudinal gradient and temporal periods in a subtropical montane stream in Northwest Argentina

The objective of this study was to analyze the spatial and temporal dynamics of Chironomidae larvae assemblages in a subtropical mountain river basin of northwestern Argentina. We hypothesized that they would respond to (1) environmental changes along the altitudinal gradient in the Yungas forests; (2) environmental changes caused by spates (e.g., increased discharge or sediment transportation). We sampled five sites along an altitudinal gradient of ca. 1,500 m (from 680 to 2,170 m) during low-water and high-water period for 2 years. The Chironomidae larvae assemblages varied along the altitudinal gradient and between sampling periods based on an indicator species analyses and an ordination analyses (NMDS). The best indicator for high altitude sites was “Genus X” followed by Onconeura sp.2, “Genus 9”, “Genus 10”, and Rheotanytarsus sp.2; while Rheotanytarsus lamellatus, Oliveiriella sanjavieri, and Thienemanniella sp. were good indicators for low altitude sites. O. sanjavieri and R. lamellatus were the best indicators for high-water period. The most relevant environmental variables influencing their spatial and temporal distribution were altitude, water temperature, conductivity, and pH. This study is the first to analyze and describe in detail the spatial and temporal distribution of Chironomidae larvae assemblages in northwestern Argentina, and most of the taxa reported here are new records for the region.     

The biogeography and phylogeny of schizothoracine fishes (Schizopygopsis) in the Qinghai‐Tibetan Plateau

Freshwater fish belonging to the genus Schizopygopsis are widespread in drainages throughout the Qinghai‐Tibetan Plateau and, thus, a model group with which to investigate how paleo‐drainage changes linked to historical uplifting within the Qinghai‐Tibetan Plateau influence speciation. To date, the phylogenetic and taxonomic relationships within Schizopygopsis remain controversial. In this study, we constructed a comprehensive molecular phylogeny of Schizopygopsis based on six mitochondrial gene sequences. We compared the taxonomic relationships revealed by this phylogeny with those obtained from morphological data. We also used this phylogeny to assess the extent to which the evolution of Schizopygopsis has been driven by paleo‐drainage changes linked to uplifting of the Qinghai‐Tibetan Plateau. Results indicated that all Schizopygopsis taxa formed a monophyletic group comprising five major clades, which were inconsistent with the taxonomic relationships based on morphology for this group. Our results also strongly supported the validity of S. anteroventris and S. microcephalus as distinct species within Schizopygopsis. Molecular calibrations showed that species within the middle Yangtze species diverged earlier (~4.5 Mya) than species within the Indus River (~3.0 Mya), the Mekong River (~2.8 Mya) and the Tsangpo + Salween rivers (~2.5 Mya). The most recent evolutionary splits occurred among species from the upper and lower Yangtze River, the Yellow River and the Qiadam Basin at about 1.8 to 0.3 Mya. Our molecular evidence and use of the molecular clock calibration have allowed us to associate speciation events within the genus Schizopygopsis to the formation and separation of paleo‐drainage connections caused by tectonic events during the uplifting of the Qinghai‐Tibetan Plateau (~4.5 Mya). This work underlines the dominant role of vicariance in shaping the evolutionary history of the genus Schizopygopsis. Further research using multiple loci and more extensive sampling will reveal a more complete picture of the phylogenetic relationships and biogeography of Schizopygopsis fishes.     

Review of sea snakes of the genus <Emphasis Type="Italic">Hydrophis</Emphasis> sensu stricto (Serpentes: Hydrophiidae)

The results of the genus Hydrophis revision s. str. are presented. The genus is divided into three subgenera, including Mediohydrophis subgen. nov. The validity of Hydrophis atriceps and H. (Microcephalophis) gracilis microcephalus is confirmed. New data on the distribution of H. klossi is given.Original Russian Text Copyright © 2004 by Biologiya Morya, Kharin.     

中国种子植物新资料

【目的】青藏高原因其特殊的地理位置、丰富的植被类型及复杂多变的气候条件,使其拥有独特而宝贵的植物资源。明确该地区植物本底资料及地理分布对本区域植物区系研究有着十分重要的意义。【方法和结果】文章以西藏自治区定日县嘎玛沟区域高山植物多样性及区系调查为基础,发现3个中国新记录种,即盔角马先蒿(Pedicularis cornigera T.Yamaz.)、细齿滇藁本[Hymenidium dentatum(DC.) Pimenov&Kljuykov]、噶穆兔耳草(Lagotis kunawurensis Rupr.)。【结论】文章对以上3个中国新记录种进行报道,对于研究该地区植物组成具有一定参考价值,同时为青藏高原植物多样性保护及植物系统分类补充新资料。     

Chromosome‐level genome assembly of Triplophysa tibetana,a fish adapted to the harsh high‐altitude environment of the Tibetan Plateau

Triplophysa is an endemic fish genus of the Tibetan Plateau in China. Triplophysa tibetana, which lives at a recorded altitude of ~4,000 m and plays an important role in the highland aquatic ecosystem, serves as an excellent model for investigating high‐altitude environmental adaptation. However, evolutionary and conservation studies of T. tibetana have been limited by scarce genomic resources for the genus Triplophysa. In the present study, we applied PacBio sequencing and the Hi‐C technique to assemble the T. tibetana genome. A 652‐Mb genome with 1,325 contigs with an N50 length of 3.1 Mb was obtained. The 1,137 contigs were further assembled into 25 chromosomes, representing 98.7% and 80.47% of all contigs at the base and sequence number level, respectively. Approximately 260 Mb of sequence, accounting for ~39.8% of the genome, was identified as repetitive elements. DNA transposons (16.3%), long interspersed nuclear elements (12.4%) and long terminal repeats (11.0%) were the most repetitive types. In total, 24,372 protein‐coding genes were predicted in the genome, and ~95% of the genes were functionally annotated via a search in public databases. Using whole genome sequence information, we found that T. tibetana diverged from its common ancestor with Danio rerio ~121.4 million years ago. The high‐quality genome assembled in this work not only provides a valuable genomic resource for future population and conservation studies of T. tibetana, but it also lays a solid foundation for further investigation into the mechanisms of environmental adaptation of endemic fishes in the Tibetan Plateau.     

青藏高原草地地上生物量估算

及时准确评估草地产草量对草地资源的科学管理和可持续发展具有重要意义。青藏高原自然环境特殊,气候差异显著,地形复杂,仅依靠遥感信息准确监测草地地上生物量(Aboveground Biomass,AGB)变化有较大限制。基于青藏高原草地AGB野外实测数据与Landsat遥感影像,探索了植被指数表征草地AGB信息的有效性,评估了气象和地形信息对准确估算草地AGB的影响,综合利用气象、地形和遥感信息,在新一代地球科学数据和分析应用平台(Google Earth Engine)上构建了梯度增强回归树草地AGB估算模型,绘制了青藏高原多年草地AGB空间分布图。结果表明:(1)基于单因素遥感因子的线性回归模型仅能解释8%-40%的草地AGB变化情况,其中绿色归一化植被指数(Green Normalized Difference Vegetation Index, GNDVI)对草地AGB解释能力较强(40%)。(2)基于遥感因子构建的梯度增强回归树模型测试集R²为0.57。分别添加气象、地形信息,模型对草地AGB的估测准确性有所提升,测试R²为0.62和0.63。(3)基于气象、地形和遥感因子的多因素估测模型能够提高草地AGB估测精度,经递归特征消除法优选后,基于13个特征变量的梯度增强回归树模型拟合效果最好(训练数据集R²=0.79,RMSE=43.42 g/m²,P<0.01;测试数据集R²=0.66,RMSE=53.64 g/m²,P<0.01),可以解释66%草地AGB变化情况。(4)2010年青藏高原平均AGB为94.58 g/m²,2015年93.63 g/m²,2020年100.78 g/m²。青藏高原西北部草地AGB较低,东南部草地AGB较高,整体呈现自西北向东南逐渐增加的分布格局。研究结果为准确估算青藏高原草地产草量和碳储量等研究提供重要参考。     

滇西北高山冰缘带植物新记录

高山冰缘带是陆地上海拔最高的植被带,自然条件恶劣,难以到达。滇西北高山冰缘带植物区系具有丰富的物种多样性,特有性高。该文对滇西北高山冰缘带进行植物多样性调查,通过采集标本、查阅植物志及模式标本等参考资料进行了形态特征研究。结果表明:发现云南新记录属1个,即囊种草属(Thylacospermum Fenzl); 新记录种5个,即囊种草 [Thylacospermum caespitosum(Camb.)Schischk]、红萼蝇子草 [Silene rubricalyx (Marq.)Bocquet]、狭叶丛菔(Solms-laubachia angustifolia J. P. Yue, Al-Shehbaz & H. Sun)、圆齿鸦跖花 [Oxygraphis endlicheri (Walp.)Bennet & S. Chandra]、密垫火绒草 [Leontopodium haastioides (Hand.-Mazz.)Hand.-Mazz.]。这些新发现一方面丰富了滇西北高山冰缘带的植物区系资料,另一方面说明了高山冰缘带的植物多样性调查仍然存在不足。针对青藏高原高山冰缘带特别是植物多样性调查薄弱及空白地区,细致和深入的调查工作亟待开展和完善。     

Length‐weight relationships of three fishes from the Nujiang River,China

The length‐weight relationships (LWR) for three fish species collected from the Nujiang River, China, were determined. Fishes were caught quarterly by drift gill net (stretched mesh size: 4 cm, depth: 2–4 m) and cast net (mesh size 1 cm; depth: 1–2 m) from May 2016 to July 2017. The values of parameter b in the LWR equations were estimated as 2.69 for Balitora nujiangensis Zhang & Zheng, 1983, 2.80 for Glyptothorax deqinensis Mo & Chu, 1986 and 2.94 for Pseudexostoma brachysoma Chu, 1979, respectively.