Alpine shrublands, as a zonal vegetation, are widely distributed on the Qingzang Plateau, and play ecological functions such as soil and water conservation, conservation of water resources, and biodiversity protection in the regional ecosystem. This study used a unified and standardized method to set up 58 quadrats to investigate the species composition, quantitative characteristics and habitat information of the main alpine shrublands of the Haizi Mountain in Batang, China. Based on “Vegegraphy of China” compilation and research standards, the alpine shrublands in this area can be divided into three vegetation types, 11 alliances, and 21 associations. This paper presents descriptions on the characteristics for each association and provides the original data from all survey plots.

Aims Subalpine dark coniferous forests are an important representative of the cold-temperate coniferous forests in China. Dark coniferous forests dominated by spruce (Piceaspp.) and fir (Abies spp.) are the main body of subalpine forests on the eastern edge of the Qingzang Plateau and an important ecological defense in the upper reaches of the Yangtze River in China. In this study, we examined the community composition and structure of such a dark coniferous forest based on the first census data of the 25.2 hm² Wanglang forest dynamics plot in western Sichuan.

Methods The plot was established following the standard protocol of Forest Global Earth Observation Network (ForestGEO) and all free-standing stems with diameter at breast height (DBH) ≥ 1 cm were tagged, mapped, measured and identified to species.

Important findings A total of 56 574 individuals belonging to 46 species, 27 genera and 15 families are tagged, including 4 coniferous species, 6 evergreen broad-leaved species and 36 deciduous broad-leaved species. There are 13 rare species (≤1 individuals per hm²), accounting for 28.26% of the total number of species and 0.16% of the total number of individuals in the plot. Abies fargesiivar. faxoniana(9 440 individuals) and P. purpurea (1 645 individuals) are the dominant and constructive species in canopy, accounting for 26.03% and 10.69% of the total importance value, and 55.22% and 24.84% of the total basal area (37.87 m²·hm^-2), respectively. The number of individuals of deciduous broad-leaved species accounted for 78.48% of the total individuals. Among them, Philadelphus purpurascens, Lonicera nervosaand Euonymus frigidusare the dominant species in shrub layer. The number of individuals of evergreen broad-leaved species is 268, and all these species belong to genus Rhododendron. The composition of the size distribution shows typical characteristics of old-growth forests. Picea purpurea is the largest tree species (max DBH = 127.07 cm) and the mean basal area (0.14 ± 0.18) m² is much higher than that of A. fargesiivar. faxoniana(0.056 ± 0.11) m². The size class distribution of all woody species shows an inverse J-shaped distribution, indicating that the community is in a stable and healthy recruitment state. Results of the point pattern analysis reveal that the five dominant tree species (important values ≥5) all show aggregated distribution patterns. However, as the spatial scale increases, all five species tend to be randomly distributed. The results of this study provide basic information for future studies on the diversity maintenance and regeneration mechanisms of subalpine dark coniferous forests in western Sichuan, and the conservation and management of this unique forest ecosystem.

Plot-based data are an important foundation for studying plant community characteristics and compiling vegetation monographs, vegetation map, and vegegraphy. It is the key data source of studies in vegetation ecology. To understand the species composition, community characteristics, and distribution pattern of special plateau vegetation on the Qingzang Plateau (QZP), this study uses the data of 338 sites including 758 plots in different regions of the QZP from 2018 to 2021 to analyze the species composition, floristic characteristics, and vegetation classification of plateau plant communities. A plot-based dataset of plant community on the QZP is then established. The 758 plots have 837 plant species belonging to 279 genera from 65 families in the alpine and temperate vegetation communities. The largest number of species are found in five families: Asteraceae (134 species), Poaceae (88 species), Fabaceae (75 species), Rosaceae (43 species), and Cyperaceae (40 species), as well as five genera: Artemisia (29 species), Pedicularis (27 species), Saussurea (25 species), Astragalus (23 species), and Poa (23 species). The floristic composition is mainly temperate (145 genera) and cosmopolitan (36 genera). The growth forms of the species are mainly herbs (83.51%) and shrubs (10.87%), and the life forms of herbs and woody plants are mainly perennial herbs (88.23%) and deciduous shrubs (83.67%), respectively. A total of 338 sites can be divided into four vegetation formation groups, 10 vegetation formations, 20 vegetation subformations, 78 alliance groups, and 117 alliances, in which 34 are steppe alliances, 33 are meadow alliances, 33 are desert alliances, 14 are shrubland alliances, and 3 are coniferous forest alliances. This dataset covers most of the alpine shrubland, meadow, steppe, desert, and temperate steppe, desert vegetation regions of the QZP. This work provides a solid foundation for exploring the vegetation characteristics and regularity of vegetation zonal differentiation and determining the impacts of climate change and human disturbances on alpine vegetation and their ecological restoration. The dataset also provides a reference for the updating of the next generation of China's vegetation map.

Climate diagram can be used to reflect visually observation data of temperature and precipitation as well as information of weather stations. It is an effective tool for studying the relationship between vegetation and climate. This paper aims to provide the atlas of climate diagrams of the Qingzang Plateau, based on the 30-year averaged observational records of national surface weather stations during 1951-1980 and 1981-2010, respectively, in order to understand the plateau climate feature of every vegetation region and to further explore the vegetation- climate relationships on the plateau. The atlas of climate diagrams of 205 weather stations on the Qingzang Plateau for both the two 30-year periods were produced according to the standard of climate diagrams in Vegetation of China. Results showed that the temperature and precipitation of the Qingzang Plateau were overall low in the whole year but relatively higher in summer, and differed obviously among different vegetation regions. The mean annual temperature and annual precipitation showed an increasing trend from the first 30-year period of 1951-1980 to the later one of 1981-2010. Although the number of weather stations in the western plateau is very sparse, this climate diagram dataset covers every vegetation regions of the plateau surface. This atlas can be used effectively to study the relationships between vegetation and climate, and conveniently to display the climate environment of the plateau.

Aims Juniperus community is an important component of natural forest resources in the Three-River-Source Region, which is significant in maintaining biodiversity and ecological security on the Qingzang Plateau. Yet, the information on the characteristics of the Juniperus community is lacking due to their special geographical location and varied topography. In this study, the main vegetation types of Juniperus community were investigated, and the main characteristics of each community type were described quantitatively by analyzing data from 53 plots. Methods Based on the analysis of forest resources inventory data in the Three-River-Source Region, the representative distribution area of Juniperus was selected to set up 7 sites, a total of 53 plots. Through the investigation of field communities and plot properties, the importance of each species was quantified and calculated. The principle of life form and dominance methods in Vegetation of China were used to determine community types. Important findings (1) The Juniperus plant community in the Three-River-Source Region was divided into 6 alliances, and then further divided into 15 associations. (2) In total, 142 species of seed plants were recorded, which was belonged to 34 families and 90 genera. Among them, Compositae was the major family, accounting for 16.20% of the total species. (3) The vertical structure of the community was obvious, in which the dominant species in the tree layer was single. The dominant species in the shrub layer were Berberis diaphana, Potentilla glabra and shrubby Juniperus tibetica. The herb layer were dominated by Carex and Pedicularis. (4) Among the geographical elements of seed plant species, the Temperate distribution accounted for 52.59% of the total species, while the rest was Chinese endemic species accounting for 47.41%. Temperate Asian, East Asian and Central Asian were the dominated areal-types in the Temperate distribution. Furthermore, the floristic elements of Hengduanshan flora and Tanggut flora were mixed formed the unique characteristic areal-type in the region.

Pollen record is an essential data for reconstructing paleovegetation and paleoclimate. It is important for the studies of paleoenvironmental evolution, characteristics of paleoclimate change and simulation of paleobiogeochemical cycles from site to regional and global scales. In this paper, we collected and sorted out the pollen data records from published and unpublished Chinese literature between 1960 to 2020. The records included sample numbers, sampling locations (latitude, longitude and altitude of sampling sites), sample types, data sources, data types, surrounding vegetation, references, and pollen taxa, their compositions as well. They were filtered and standardized to integrate a pollen dataset of China. This dataset consists of 4 497 modern pollen sampling sites, including 660 published data from the Chinese Quaternary Pollen Database, 1 763 from early published data and 2 074 from recently collected data, belonging to 772 pollen taxa. The samples were mainly from surface soils (3 332 sites), and the rest were from moss plosters, surface sediments from lakes and the ocean. The sampling sites are widely scattered around China representing different geographical regions and vegetation types: 24.91%. in the temperate desert region, 24.02% in the subtropical evergreen broad-leaved forest region, followed by the temperate grassland region (16.14%) and alpine vegetation region of Qingzang Plateau (15.83%). The data can be divided into the raw data (58%) and numerical data (42%) according to their sources, and grain count (59%) and calculated pollen percentage (41%) by data type as well. The database constructed from the samples over China during the past half-century+ period is, though by far from complete, good representation of most of the areas in China, which can be effective in the reconstruction of past vegetation and climates as modern verification.

Stipa sareptana var. krylovii alliance is one of the typical steppes endemic to Central Asia. The eastern border of its distribution is adjacent to the meadow steppes on the Hulunbeir Plateau, the western border extends to the desert steppes on the Ulanqabu Plateau and Tianshan Mountains, and the southern border lies among the warm temperate steppes on the Loess Plateau. The distribution of this alliance also spreads into the alpine steppes on the eastern margin of the Qinghai-Xizang Plateau. The broad its distribution suggests that S. sareptana var. krylovii alliance has wide ecological adaptability. In this study, we described and analyzed the eco-geographical distribution, community characteristics and classification of S. sareptana var. krylovii alliance based on data from 117 plots. The results showed that there are 336 seed plants belonging to 36 families and 131 genera in these plots. The families with more than 15 species are Gramineae, Compositae, Leguminosae, Rosaceae, Chenopodiaceae and Liliaceae. Among all species in these plots, 91.67% are rare species with occurrence frequency smaller than 20%. Besides S. sareptana var. krylovii, the most common species in this alliance include Cleistogenes squarrosa, Heteropappus altaicus, Agropyron cristatum, Koeleria cristata, Potentilla bifurca, Salsola collina, Allium tenuissimum and Leymus chinensis. In addition, hemicryptophytes are the most common life form within the surveyed plots, accounting for 66.37% of all species. Xerophytes are the most common water ecological type, accounting for 61.19% of all species. East Palearctic element was the major floristic geographical element, accounting for 33.33% of all species. Based on the China Vegetation Classification System, S. sareptana var. krylovii alliance could be classified into 6 association groups and further into 45 associations.

Aims Fagus L. has a disjunct distribution in the northern temperate zone, and there is a rich collection of Tertiary fossils from East Asia, Europe and North America. A panbiogeographical analysis of Fagus was undertaken to analyze the distribution pattern and evolution of the genus.
Methods Distribution data of 581 records of 10 species were obtained from herbaria and monographs. Track analysis of panbiogeography and software MartiTrack were used for data analysis.
Important findings Results indicated that there was no generalized track linking the distributions among China, Japan, Europe and North America or even between China and Japan, two adjacent areas in East Asia. Two regional generalized tracks were only found within China and Japan. These facts imply that the Fagus distribution cannot be explained by dispersal. Dispersal probably only occurred in limited and/or local regions and not as dispersal across the northern temperate zone in the Tertiary. The disjunction most likely resulted from (1) geological historical events such as Tethys westward movement, Qinghai-Tibet Plateau uplift, and Asian monsoon action, (2) climate change since the Tertiary, especially climate fluctuation during Quaternary glaciation, and (3) Fagus biological characteristics with regard to humid and temperate climate and annual rainfall.

Pollen data are the foundation of reconstructing past vegetation patterns and of studying past climate changes and interactions among atmosphere, biosphere and human activities. We searched for pollen-related literature published and reported from the 1960s to 2008 and collected late Quaternary pollen sampling information for China. We focused on the past 20 000 years before present (aBP), especially the Holocene. Information includes site name, detailed location in text and in latitude, longitude and elevation, sample type, sediment depth, number of pollen samples, radiocarbon dating, time period, and reference. There are 2 324 surface pollen samples from soils and lakes and 987 cores/profiles of sediment fossil records. Among them there are 714 fossil pollen sampling sites with high quality data of pollen and radiocarbon dating. Despite research has been performed by domestic and international paleo-scientists in collecting pollen samples and in Quaternary studies in China, geographical gaps exist due to the limitation of financial support and poor topographical conditions. These include the northern and northwestern desert areas, non-settlement area of the Tibetan Plateau, mountainous areas of middle-southern China and highly disturbed areas of eastern China. More pollen sampling records are needed to update and complete the information database. Such information will greatly benefit the Quaternary Chinese Pollen Database. Furthermore, scientific questions can be addressed based on the databases, such as what the geographical patterns of paleovegetation in China were during the late Quaternary, what were the key times of vegetation shifts (abrupt changes), what were the driving factors of vegetation changes, climate change or human disturbances, and how have vegetation changes influenced local and regional climates?

Estimating carbon storage in terrestrial ecosystems has been a central focus of research over the past two decades because of its importance to terrestrial carbon cycles and ecosystem processes. As one of the most widespread ecosystem types, China’s grasslands play an important role in global change research. The grasslands in China, which are distributed primarily throughout the temperate regions and on the Tibetan Plateau, were classified into 17 community types. In the present study, a statistical model was established to estimate grassland biomass and its geographical distribution in China based on a grassland inventory data set and remote sensing data (Normalized Difference Vegetation Index) using GIS and RS techniques. We found that there was a significant correlation between aboveground biomass density and the maximum annual NDVI when expressed as a power function (R2=0.71, p<0.001). The aboveground biomass was estimated to be 146.16 TgC (1Tg=1012 g) and belowground biomass was estimated as 898.60 TgC (6.15 times of the above biomass) for a total biomass of 1 044.76 TgC. This value accounts for about 2.1%-3.7% of the world’s grassland biomass. The grassland biomass is distributed primarily in the arid and semiarid regions of Northern China and the Qinghai-Xizang Plateau. The average biomass density of China’s grasslands was 315.24 gC·m-2, smaller than the world average. The aboveground biomass density decreases from southeastern China toward the northwest corresponding with changes in precipitation and temperature. Furthermore, aboveground biomass density reached the lowest levels at 1 350 m elevation and peak levels at 3 750 m above sea level which most likely is related to China’s three-step topographical background. The ratio of total biomass of grassland to forest biomass in China is 1/4, much higher than that of the world, suggesting a greater contribution of grasslands to China’s carbon pool.

This paper deals with some ecophysiological characteristies of plant growth, parameters of physiology, material accumulation and community composition in apline bushland. The results are as follows:

1 Leaf area index and average rate of growth of some species of Gramineae, Cyperaceae m Dasiphora fruticosa alpine shrub are increased with decreaded grazing intensity. The height and coverage of the community were negatively correlated with grazing intensity (P<0.001).

2. Changes of the aralytical growth parameters: LAR, SLA, LWR and LAI were negatively correlated with grazing intensity. Leaf area index was positively correlated with biomass (P>0.005); Aboveground biomass was negatively correlated with grazing intensity (P<0.001).

3. The species numbers of Gramineae, Cyperaceae in Dasiphora fruticosa shrub community were decreased in heavily grazed area and increased in lightly grazed area. But the proportion of Forb was increased with heavy grazing and decreased with light grazing. Thus light grzaing in alpine scrub showed profitable for plant growth and regeneration.

Qinghai Lake is the largest inland one in China. It is situated in the northeastern part of Qinghai-Xizant (Tibetan) Plateau. The area of Qinghai Lake region is 29661km2. The lake area is 4304.5km2 measured in 1986.

The vegetation types distributed in Qinghai Lake region mainly include desert vegetation, temperate steppe, alpine shrub, alpine meadow, alpine steppe and alpine subnival vegetation. In this region, the dominant vegetation types are of alpine ones, and the temperate types are only distributed in the area near the lake.

Based on our investigation and analysis, some characteristics of vegetation succession in this area are showed as follows:

(1) The forest is a stage of regression. Only two tree species(Sabina przewalskii and Picea crassifolia)are distributed as relic species in this area.

(2) The alpine vegetation types are relatively developing, but the temperate vegetation are not.

(3) The vegetation around Qinghai Lake has its individual characteristics and special successional trend, In general, vegetational landscape in Qinghai Lake region has been tending to become one which has a strong adaptation to extremely high and harsh habitats.

According to the study on succession of aquatic environment and palaeoclimatology and ancient sporopollen analysis. The climate of this area tended to become colder and drier although the fluctuation did exist during the process of change. Under the increasing pressure caused by this climatic change, the plant species which adapted the change got developed, and the development of individual species which did not adapt to this change was suppressed and inhibited, This is the reason why vegetation around Qinghai Lake tended to success towards the type adapting extremely high and harsh habitats.

It may be made such ecological analysis for flora formation, the correlation between plant species the distribution patterns in ecological series and 2 and 3 dimensional ordinations of subalpine forest vegetations in western Sichuan as follows:

(1) The flora of subalpine forest in this region has been formed by three process--the convergence of external flora components; the vertical differentiation during the orogenic movement; the internal differentiation within the mountain region accompanying with ecological isolation in south-western China.

(2) As result of a plexus or semi-matrix diagram of species based on correlation analysis for 6 major subalpine forest associations in western Sichuan, the shrub and herb species could be divided clearly into 2 close linkage natural groups-the sciohydrophytic one in higher elevation and the semixerophytic one in lower elevation, and a losse mesophytic group. The mosses could be divided into a close semixerophytic and a close thermophytic group in lower elevation, and a losse scio-hydrophytic group in higher elevation.

(3) Plant species distributing along ecological series are in 4 patterns: 1. narrow in elevation in synusia form on the whole; 2. narrow in elevation in scattered form on the whole; 3. broad in elevation, but narrow distribut in elevation only in synusia form; 4. broad in elevation. The last one has less indicative significance.

( 4) In 2 and 3 dimensional ordination, the samples of 6 major forest associations may be plotted according to the axes related to the elevation, moisture and soil fertility gradients in ordination fields. The positions on each axis and distance values between associations can quantitatively reflect the difference between associations.