Vegegraphy, a newly-created term in this paper and a compound word of prefix “vege-” of “vegetation” and suffix of “-graphy”, is a series of monographs that describe detailedly species composition, structures, functions, environmental settings, and distribution of a set of plant communities and/or their combinations for each vegetation type, using community data from vegetation survey. Its compilation is very huge, comprehensive, time-consuming research project, and great importance in the ecological research, vegetation restoration and utilization, biodiversity conservation, and environmental monitoring. This article first documents major community characteristics (i.e., species composition, structures, physiognomy, and dynamics), and historical development and current state of vegetation survey in China and worldwide, then reviews historical studies on vegetation classification systems and their revisions, and finally discusses compilation of vegetation of China and classification of vegetation types used for the compilation. For the revision of vegetation classification systems, we mainly revised high-level units of previous classification systems and the corresponding English terms. Following this revised classification system, the hierarchical level of China’s vegetation classification is expressed as high-level units (Vegetation Formation Group, Vegetation Formation, and Vegetation Subformation), medium-level units (Alliance Group, Alliance, and Suballiance), and lower-level units (Association Group and Association), respectively. In the Vegetation Formation Group unit, nine types were divided as Forest, Shrubland, Herbaceous vegetation, Desert, Swamp & Aquatic Vegetation, Alpine Tundra & Sparse Vegetation, Cultivated Vegetation, Urban Vegetation, and Non-Vegetated Area. For the compilation of vegetation of China and the classification of vegetation types, we used the high-level unit, Vegetation Formation, as the Volume of the vegegraphy, and used a specific term, “Vegetation type”, as the Issue under the Volume. The Vegetation type here is not a real vegetation classification unit but is a combination of a set of vegetation units (i.e., Vegetation Subformation and/or Alliance Group and/or Alliance) in which there exist the same or similar constructive species or the same dominant taxa (species or genus) in the communities. The determination of “Vegetation type” follows the four principles: identity of dominant taxa and life form, relative importance of habitats, difference of vegetation characteristics and application, and practicability of vegegraphy. As a result, the vegetation of China (Vegegraphy of China) completed will be composed of 48 volumes and about 110 issues.

An encyclopedia of Chinese vegetation is going to be compiled as a series of books, and comments are sought to revise the “Vegetation Classification System of China” (VCSC). These require several key decisions. First, the principle of VCSC proposed by Vegetation of China (1980) that “the higher rank of classification unit would be based on the physiognomy of vegetation, while the middle and lower rank emphasized on species composition and community structure” should be maintained because it is corresponding with the current trends of international vegetation classifications. Second, VCSC should classify Chinese vegetation to be compatible with global vegetation classification, so that the terms and concepts will be widely accepted internationally. Third, “Association”, a fundamental classification unit described by the series of books of Chinese vegetation, should be defined and used consistently, so that misunderstandings between northern and southern associations can be avoided. Fourth, the hierarchy in the classification of vegetation generally should be rigid, but different ranks remain open and flexible, i.e., upper-level units can be supplemented to meet future needs. A draft of the VCSC (from class to vegetation type) is proposed in this paper.

Aims Larch forests are important for timber harvesting and water-soil conservation in North China. To explore the distribution, community structure and species diversity of larch forests is important for the vegetation conservation and sustainable utilization in North China.
Methods We collected species composition and local environment for 215 forest plots dominated by three common larch species, namely, Larix principis-rupprechtii, L. kaempferi and L. chinensis, in North China during 2000-2017. Among these types, L. kaempferi forests are planted, while L. chinensis forests are almost natural, and most of L. principis-rupprechtii forests are natural. Based these data, we used the canonical correspondence analysis (CCA) to explore the relationship between species composition and environment. We also explored the pattern of community structure and species diversity of these three forests in relation to environmental factors.
Important findings Mean annual air temperature (MAT) was the most important factor for the distribution of these larch forests. The proportion of natural forest decreased, while that of planted forest increased, with MAT. Diameter at breast height (DBH) and height distribution of three larch forests were right-skewed, indicating that all of these larch forests are at relatively stable successional stage. Species richness differ remarkably among different larch forests, which was highest in the L. chinensis forests (39.3 ± 17.9), followed by the L. kaempferi forests (37.4 ± 22.4), and lowest in the L. principis-rupprechtii forests (planted forests 27.2 ± 17.7, natural forests 27.5 ± 13.8). Species richness, the maximum DBH and the maximum height decreased with latitudes and longitudes. Species richness, the maximum DBH and the maximum height increased with annual precipitation. However, species richness showed no significant trend, and the maximum height increased, while the maximum DBH decreased, with MAT. The patterns of species richness along geographical and climatic gradients were consistent between the planted, the natural and the overall (including both planted and natural) larch forests. However, the patterns of community structure differed remarkably among planted, natural and overall larch forests. The maximum height of planted forests increased, while that of natural forests decreased, with latitude and longitude. The maximum DBH and height of natural forests decreased, while those of planted forests increased, with MAT and annual precipitation, respectively.

The effectiveness and accordance of four popular climate vegetation classification models (Penman model, Thornthwaite model, Holdridge Life Zone System and Kira model) for the geographic distribution of Chinese vegetation is compared using the KAPPA agreement statistic method. The results indicate that those four classification models work well in the first level of Chinese Vegetation Division. The KAPPA value of the Holdridge Life Zone System (0.57) is the largest among the four models. It showed that it is the best one among four models in simulating the geographical distribution of Chinese vegetation. However, regarding some specific regions, for example, the Tibetan plateau, all of the models need to be refined or to take new affecting factors into account in order to obtain a better simulation of the geographic distribution of vegetation. 1) The Penman model could simulate the geographic distribution of vegetation in temperate steppe and Tibetan plateau with a KAPPA value greater than 0.50. It is the best one for Tibetan plateau among the four models. 2) The Thornthwaite model could give the best simulation for tropical rain forests and seasonal rain forests with KAPPA value of 0.40. It might compensate for the ineffectiveness of the Holdridge Life Zone System in this area. 3) The Holdridge Life Zone System is the best one among the four models for simulating the geographical distribution of vegetation in China based on the first level of vegetation division in China, but it still fails to simulate west seasonal rain forests and rain forests (52), west temperate steppe (63), Tibetan plateau temperate desert (86) and Tibetan plateau temperate steppe (84). 4) The Kira model simulates the subtropical evergreen forest zone very well, and its KAPPA value in this zone is close to that of the Holdridge Life Zone System. Also it could simulate moderately well the geographical distribution of vegetation in low elevation and humid/semihumid area, but it was far from the ground truth when applied to the regions of temperate desert and Tibetan Plateau. This research also implies that it is urgent to develop better climate vegetati on classification model in order to provide better input to the general circulation models (GCMs) with the geographic distribution of vegetation and to accurately evaluate the possible effects of climate change on vegetation.

Vegegraphy, a compound word of prefix “vege-” of “vegetation” and suffix of “-graphy” (description), is a series of monographs that describe species composition, structures, functions, distribution and environmental settings of a set of plant communities and/or their combinations. The Vegegraphy of China, which will be composed of 48 volumes and about 110 issues, is the first version to describe the medium-level units (Alliance Group, Alliance) and the lower-level units (Association Group, Association), and summarizes the higher-level units (Vegetation Formation Group, Vegetation Formation, Vegetation Subformation) in the Chinese Vegetation Classification System. The description of the higher-level units is highly generalized, mainly based on the data and evidences from the classification and description of the medium- and the lower-level classification units of the Chinese vegetation classification system, focusing on the geographic distribution, natural environment, community physiognomy, vegetation type and diversity, dominant species, values for biodiversity conservation, and the status of current vegetation resources at the scales of both worldwide and China. It is an important revision and expansion of the relevant content of Vegetation of China (1980) and will be the most authoritative and accurate description of the basic characteristics of Chinese vegetation. Alliance Group in each issue is briefly described on geographical distribution, natural environment, vegetation types, significance and conservation etc. Alliance as a key medium- level unit is to be described on several aspects, i.e., geographical distribution, natural environment, ecological characteristics, vegetation composition, vegetation structure, vegetation types and characteristics, biological characteristics of dominant species, biomass and productivity, vegetation dynamics and succession, and significance and conservation. As a core content of the above mentioned aspects, vegetation classification and description are conducted under the guidance of the “80 scheme” of Vegetation of China, using vegetation survey data as credentials to quantitatively differentiate vegetation types accordingly. Specifically, a vegetation classification scheme is determined based on supraterraneous stratification, and a set of diagnostic species while vegetation descriptions focus on physiognomy, community structure, species composition, including quantitative features of dominant species, companion species, constant species and accidental species, as well as their environmental preferences. In this study, we first put forward a code of vegetation nomenclature for the medium-level units (Alliance Group, Alliance) and the lower-level units (Association Group, Association) in the Chinese Vegetation Classification System. According to this vegetation nomenclature, the name of a vegetation type is composed of the name of a diagnostic species (may also be a dominant species) of each layer of the vegetation type and the name of the higher-level units (Vegetation Formation or Vegetation Formation Group) to which it belongs, which guarantees both scientific soundness and practical sense of the vegetation nomenclature. Contents and protocols for the research and editing of “Vegegraphy of China”, including vegetation survey and sample collection, literature compilation, climate, soil and topography data collection and compilation, vegetation classification, vegetation nomenclature, vegetation description outlines, are elaborated or exemplified in detail.

The Song-Nen Plain is located in the northeast of China. The plain has a temperate semihumid continental climate. The summer is hot and rainy, but the winter is very cold and dry with little snow. The meadow steppe is developed as a result and has become a zonal vegetation type of the region. The combination of plants and distribution of plant communities appear to be controlled mainly by the edaphic condition.From a combination of component species and biotope, using qualitative and quantitative analysis, namely, a polythetic hierarchical agglomerative classification(MULVA-4 PROGRAM) ,the steppe vegetation on the Song-Nen Plain can be divided into different units. These units are classified as 4 orders, 12 alliances and 40 associations, depending on species composition, especially ecological groups of species, similarity coefficient and dynamic feature of communities, so that a hierarchical system for the steppe vegetation of the Song-Nen Plain is tentatively established. The system reveals the relationship between combination of plant and biotope. The similarity and difference in component species of various units demonstrate not only the whole property but also the continuity and discontinuity of the steppe vegetation. It has been found that there is correspondence between high syntaxa and site type. Based on this correlation the classification of vegetation leads to practical considerations for the management of the steppe in Song-Nen Plain.

Aims Shrub encroachment is a critical ecological problem in arid and semi-arid ecosystems worldwide. The effects of shrub encroachment on ecosystem structure and function of grasslands are complicated and need to be explored in future studies. Our objective is to examine the effects and pathways of shrub encroachment on ecosystem structure and function in a typical steppe of the Inner Mongolia grassland.
Methods Three grassland sites with different degrees of shrub encroachment (i.e. light, moderate, heavy) were selected in the Xilingol Nei Mongol, of which Caragana microphylla was the dominant shrub. Species richness and composition, aboveground net primary productivity (ANPP), soil property, and plant functional traits of dominant species were determined in this study. In addition, species diversity, functional attribute diversity, community-weighted mean traits, and vegetation leaf and soil carbon and nitrogen pools were further calculated.
Important findings 1) The species richness, functional attribute diversity and community-weighted mean traits differed significantly among three grassland sites, and species diversity and functional diversity were relatively higher in the moderate shrub-encroachment site, indicating moderate shrub-encroachment favors biodiversity maintenance. 2) The aboveground net primary productivity of heavy shrub-encroachment grassland was significantly higher than those of light and moderate shrub-encroachment grasslands, which was mainly due to a shift in functional group composition, that is, the proportion of annuals and biennials to perennial grasses and forbs increased greatly with intensifying shrub encroachment. The vegetation leaf and soil carbon and nitrogen pools differed little among three sites. 3) Shrub encroachment did not directly affect ecosystem function, including ANPP, vegetation and soil nutrient pools, but it indirectly affected them through pathways of the shift in functional group composition and changes in soil property and functional diversity. Particularly, the shift in functional group composition and intensified soil drought and basification was separately important biotic and abiotic factors for variations in ecosystem function.

The principles and scheme of vegetation classification system of China (China-VCS) were first proposed by Hou in China’s Vegetation in 1960. An improved hierarchy framework and criteria of China-VCS were published in Vegetation of China in 1980. China-VCS was revised in Vegetation of China and Its Geographic Pattern — Illustration of the Vegetation Map of the People’s Republic of China (1:1 000 000) in 2007 and in Flora and Vegetation Geography of China in 2014. Song proposed a new scheme in the text book Vegetation Ecology in 2017. To facilitate Chinese vegetation study and the compilation of the book series on the vegetation of China (Vegegraphy of China), this paper provides a revised scheme of China-VCS. The scheme adopts the principles, units and hierarchy structure in the Vegetation of China that was considered as a milestone in the development of Chinese vegetation science. Based on the phytocoenological-ecological principles, plant community features and its ecological conditions are considered as the key criteria for vegetation classification. There are three levels including eight units in the hierarchy framework of China-VCS: upper level (Vegetation Formation Group, Vegetation Formation, and Vegetation Subformation), middle level (Alliance Group, Alliance, Suballiance), and lower level (Association Group, Association). Nine Vegetation Formation Groups are defined as Forest, Shrubland, Herbaceous Vegetation (Grassland), Desert, Alpine Tundra and Sparse Vegetation, Swamp and Aquatic Vegetation (Wetlands), Agricultural Vegetation, Urban Vegetation, and Non-vegetated Area. Forty-eight Vegetation Formations (30 for natural and semi-natural vegetation, 12 for agricultural vegetation, 5 for urban vegetation, and one for Non-vegetated Area) are defined, including 81 Vegetation Subformations from 23 natural and semi-natural vegetation formations. These vegetation formation groups and 30 natural and semi-natural vegetation formations were described briefly. Some issues on China-VCS, especially on the framework, criterion identifying mixed-forest, and the role of soil in vegetation classification, are discussed.

Aims As an endangered wild species with extremely small populations, Ferrocalamus strictusis narrowly distributed in South Yunnan with a small number of individuals. The survey of population structure and community characteristics of the wild population of F. strictus can facilitate understanding its endangered system and mechanisms and provide preliminary research basis for its protection.

Methods We investigated the community and population structure of F. strictus, including species composition, population density, population survivorship curve and death factors by plot surveying and sampling.

Important findings The community in which population of F. strictus is located in Mojiang has some characteristics of mountain rainforests in terms of appearance and species composition. The population density of F. strictus was 2.04 ind.·m ^-2. The survivorship curve of F. strictus was between Deevey-I and Deevey-II. The net proliferation rate (R₀) of F. strictus population was 1.10, which indicates an expanding population of F. strictus. The death of F. strictusis caused by human logging, natural death, shoot degradation and insects feeding. Among them, artificial cutting accounts for the largest proportion. Ferrocalamus strictus is a species of forest bamboos distributed in the South Asian subtropics, which is a medium-sized bamboo species. Its internode length change suddenly from the base 3-4 nodes. The longest ones exceed 1 m, which ranks at the top of all bamboo species and is closely related to its adaptation to the tropical mountain rainforest environment.

Aims Phylogenetic and functional diversity are important components of species biodiversity, and are thought to play key roles in the mechanisms of community assembly. In this study, we explore the mechanisms of community assembly in tropical cloud forest plant community in Hainan Island, in southern China, using phylogenetic and functional diversity based methods.

Methods We constructed a species pool of 186 woody plant species from three tropical cloud forest sites in Hainan Island. For these species, we measured 13 functional traits and assessed their phylogenetic signals. In addition, we measured seven environmental factors and assessed their relationships using Principal component analysis (PCA). Then we chose Rao’s quadratic entropy (RaoQ) and mean pairwise distance (MPD) indices to examine the effects of functional diversity and phylogenetic diversity on tropical cloud forest community assembly. To do this we compared these indices to expectations under null models that assume neutral community assembly. We used standard effect sizes to evaluate the influence of environmental factors on community assembly.

Important findings Canopy openness, soil total phosphorus content and slope were significant environmental predictors in tropical cloud forest. The phylogenetic signals of most functional traits were very low and not significant, indicating that the phylogenetic relationship and functional traits were not consistent with the change of historical process. The observed values of RaoQ and MPD were significantly lower than expected, and their standard effect sizes were significantly correlated with soil phosphorus content, which suggested that habitat filtering driven by soil phosphorus was the key factor driving the community assembly in tropical cloud forest.

Aims The mid-mountain moist evergreen broad-leaved forest is a montane forest vegetation type developed in the subtropical climate zones of China. However, the community structure of the forest has never been reported based on large sized plots. The present study investigated the tree species composition and community structure within a 20 hm ² plot, serving as the fundamentals for analyzing the relationships between environmental factors and spatial distribution of tree species, and a basic platform for monitoring long-term forest dynamics in the future.

Methods We established a 20 hm² plot in a forest at Xujiaba on Mts. Ailaoshan, Jingdong County, Yunnan Province in 2014. The plot was set up in accordance to the protocols of the Center for Tropical Forest Science (CTFS). All free-standing woody plants with a diameter at breast height (DBH) ≥ 1 cm were positioned, mapped, tagged, measured and identified to species in the plot.

Important findings A total of 44 168 free-standing individuals with DBH ≥ 1 cm were recorded, belonging to 104 species, 63 genera and 36 families. Trees of Fagaceae, Theaceae and Lauraceae are dominant species. At the level of genus, the floristic composition was primarily represented by both tropical (46.0%) and temperate (38.1%) elements. The 22 individual species with importance value ≥ 1 contributed 84.6% to the total abundance. The three most abundant species were Camellia forrestii, Vaccinium duclouxii and Symplocos ramosissima. Four tree species (Lithocarpus hancei, L. xylocarpus, Castanopsis wattii and Schima noronhae) had the largest basal areas, and they were also the dominant canopy tree species in the plot. The DBH distribution of all individuals in the plot showed a reversed “J” pattern, indicating numerous recruiting populations. Such a pattern was applicable to C. forrestii and S. ramosissima as well. Forty-nine rare species (those with individual number fewer than 20 in the plot) accounted for 47.1% of the species total. Evergreen species dominated the life form spectrum of the plot, making up for 94.7%, 96.2% and 94.0% in terms of importance value, total abundance and total basal area, respectively.

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.

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.

Thymus mongolicus steppe was a vegetation formation dominated by typical dwarf semi-shrub of Lamiaceae. Based on the previous literatures and primary plot data sampled during the growing seasons from 2015 to 2017, the distribution, ecological features, community characteristics and classification of Thymus mongolicus steppe were summarized. (1) Thymus mongolicus steppe is mainly distributed on the loess hills of Xar Moron River Watershed, Bashang region in the northwest of Hebei Province, the hills surrounding the Yinshan Mountains, the east part of Erdos Plateau and the northern Loess Plateau. This formation occurrs mainly on the stony slopes or loess hills with severe soil erosion. (2) In total, 167 seed plant species belonging to 101 genera of 34 families were recorded in the 91 sample sites, and families of Compositae, Leguminosae and Gramineae played crucial roles in the species composition. Eight of these families were semi-shrub and dwarf semi-shrub species, and 112 were perennial forb species. Typical xerophytes (58 species) and Meso-xerophytes (45 species) account for more than half part of all species. Eight geographic elements were involved. East Palaearctic (70 species) and East Asia (46 species) were the two major floristic elements. (3) Based on life form and dominance of species in the community, the formation was classified into 6 association groups (Thymus mongolicus, dwarf shrubs/dwarf semi-shurbs association group; Thymus mongolicus association group; Thymus mongolicus, bunchgrasses association group; Thymus mongolicus, rhizomatous grasses association group; Thymus mongolicus, Carex association group; Thymus mongolicus, forbs association group), consisting of 28 associations.

Aims There are two hypotheses on the mechanism of functional diversity driving ecosystem processes: one is the mass ratio hypothesis based on dominant species, and the other is the diversity hypothesis based on ecological niche. Both hypotheses have been supported by different studies, but their applicability and universality are still controversial. Our objective was to clarify whether the explanatory ability of these two hypotheses to productivity is influenced by the existence of intensive environmental filtering, which was flooding in this study.
Methods Three meadow communities and three marsh communities were studied over two years in the Momoge National Nature Reserve in western Jilin Province. The aboveground biomass, species diversity (species richness and Shannon-Weaver index), functional diversity (community weighted mean and Rao’s quadratic entropy), and several environmental factors were compared among different communities. The functional diversity was calculated for seven plant traits. The relationship between diversity index and aboveground biomass was explored by simple linear regression analysis and multiple linear regression analysis with stepwise method.
Important findings Both Rao’s quadratic entropy and community weighted mean could explain more variation in community productivity than species diversity. Furthermore, both mass ratio hypothesis and diversity hypothesis supported the diversity-productivity relationship. However, the mass ratio hypothesis may play a relatively greater role than the diversity hypothesis, indicating that the ecosystem function mainly depended on the functional traits of dominant species. Intensive environment filtering in terms of flooding affected the diversity-productivity relationship. The mass ratio hypothesis based on community weighted mean explained more variation of the productivity in meadow communities without flooding filtering, while diversity hypothesis based on Rao’s quadratic entropy explained more variation of the productivity in marsh communities with flooding filtering.

The main vegetation types of Desert Grassland Nature Reserve in Qitai, Xinjiang were investigated in this paper. Based on the data from 65 plot samples, the characteristics of the main desert plant communities from the main vegetation types were quantitatively described. The results showed that, the vegetation in this reserve can be divided into 12 major plant community types: Haloxylon ammodendron Simi-Arbor and Shrub Desert Alliance, Ephedra przewalskii Simi-Arbor and Shrub Desert Alliance, Gymnocarpos przewalskii Simi-Arbor and Shrub Desert Alliance, Reaumuria soongarica Simi-Arbor and Shrub Desert Alliance, Iljinia regelii Semi-Shrub and Herb Desert Alliance, Anabasis brevifolia Semi-Shrub and Herb Desert Alliance, Tamarix laxa Deciduous Broadleaf Shrubland Alliance, Kalidium foliatum Semi-Shrub and Herb Desert Alliance, Ajania fruticulosa Semi-Shrub and Herb Desert Alliance, Achnatherum splendens Tussock Grassland Alliance, Leymus angustus Tussock Grassland Alliance, Phragmites australis Tussock Grassland Alliance. Finally, 15 associations were derived from these 12 major community types.

The vegetation classification in China was updated by referring to recent advances for vegetation classification worldwide and on the basis of our former paper Recognition and Proposal on the Vegetation Classification System of China (hereafter, “Recognition and Proposal”). In this revision, the criteria for vegetation classification were discussed and unified, and a quantified standard for high, medium, and low level units in a new hierarchical classification scheme was supplemented. Compared with the old classification scheme in “Recognition and Proposal”, the units at the level of vegetation type were substantially changed. Finally, in order to improve mutual communication among international peers, a comparison was carried out between the new revised scheme and each of International Classification and Mapping of Vegetation of UNESCO, The National Vegetation Classification Standard of United States, and The Braun-Blanquet Classification Scheme.

Aims Understanding the spatial patterns and maintenance mechanisms of biodiversity is one of the central issues in ecology and biogeography. Specifically, altitudinal patterns of biodiversity have been widely explored to represent to mimic the latitudinal patterns. However, previous studies on altitudinal patterns of plant diversity have focused mainly on the taxonomic diversity, with less attention paid to the comprehensive information of taxonomic, phylogenetic evolution and functional traits. In this study, we explored maintenance mechanisms of diversity of forest communities in Mount Guandi, by comparing the altitudinal patterns of taxonomic, phylogenetic and functional diversity, based on the systematic investigation of forest communities.
Methods 52 forest plots, each with an area of 30 m × 20 m and divided into six subplots (10 m × 10 m), were investigated along the altitudinal gradient (1 409-2 150 m) in Mount Guandi, Shanxi. Name, diameter at breast height (DBH) and height were identified and measured for each tree stem with DBH ≥3 cm at each plot; name, average height, coverage and basal diameter for each shrub species were identified and measured in two of the six subplots; name, abundance, coverage and average height for each herbaceous species were identified and measured for one quadrat of 1 m × 1 m in each subplot. The indices of taxonomic, phylogenetic and functional α and β diversity were then calculated.
Important findings Species richness (S), phylogenetic diversity (PD) and functional richness (FRic) increased along the altitudinal gradient, especially in altitudes above 1 800 m. Total β diversity (β_total) and replacement β diversity (β_repl) increased, while the richness difference (β_rich) decreased, along the altitudinal gradient. The patterns of taxonomic, phylogenetic and functional diversity were significantly different between woody and herbaceous plants. S and Shannon-Wiener diversity (H′) of herbaceous plants increased more obvious along the altitude than those of woody plants. Topographic factors regulated the pattern of the herbaceous plant richness, while historical process regulated the woody plant richness. Along the altitude, β_total increased more obvious for the woody plants than for the herbaceous plants. β_repl and β_rich of woody plant showed a unimodal pattern and U-shaped pattern, while those of herbaceous plants increased or decreased, respectively. Taxonomic, phylogenetic and functional β diversity of both woody and herbaceous plants among communities increased with the environmental and geographical distances. Environmental distance had a relatively stronger effects than geographical distance on β diversity of woody plants, while environmental distance and geographical distance jointly influenced β diversity of the herbaceous plants.

Aims Stipa tianschanicavar. gobica steppe is mainly distributed on the rocky slopes or rocky hills of desert steppe region, and can also be found in rocky hills or mountains of the typical steppe area eastwardly and some rocky slopes of the desert region westwardly. The main vegetation types of S. tianschanicavar. gobica steppe in China were investigated in this paper, and based on the 115 plot samples, the characteristics of the main desert steppe plant communities from the main vegetation types were quantitatively described. And the results showed that: according to the quadrat data, 272 seed plants belonging to 38 families and 127 genera (including the subspecies, varieties and forms) were recorded in the S. tianschanicavar. gobica steppe of China, among which there were 3 gymnosperm species belonging to 1 families and 1 genera, and 269 angiosperm species belonging to 37 families and 126 genera. The families having more than 10 species were Compositae, Poaceae, Leguminosae, Rosaceae, Liliaceae, Chenopodiaceae and Caryophyllaceae respectively. Hemicryptophyte, with a total of 178 species is the dominant life form in S. tianschanicavar. gobica steppe, which accounted for 65.44% of the total species. As for the ecological type of water, xerophytes was the dominant plants, with a total of 120 species, accounting for 44.12% of all species. East Palaeo-North element areal-type (including 82 species) and Middle Asia element (included the variants) areal-type (including 80 species) were the major floristic elements, containing 30.14% and 29.41% of the total species. The coverage of 0.1%-1% was the dominant level in the cover class distribution of the species, including 63.97% of the total species. The constancy degree of I (0-20%) was the dominant level in the constancy degree distribution of the species in S. tianschanicavar. gobica steppe, containing 94.85% of all the species. In accordance with the classification principle of community-appearance, Form. S. tianschanicavar. gobica was divided into 8 S. tianschanicavar. gobica steppe association groups, and 106 associations were divided from these 8 association groups based on community survey data.

Aims The monsoon evergreen broad-leaved forest (MEBF) is the dominant vegetation type in the subtropics of Eurasian continent. It provides vital ecosystem services and supports the socioeconomic development of the societies. Recent literature indicated that the MEBF had been greatly affected by the changing climate and other disturbances such as outbreaks of insects and, consequently, shifted its species composition and structure. In this study, we aim at the long-term changes of plant species and community structure in the MEBF.

Methods Species names, diameters at breast height (DBH), and tree heights of all trees with DBH ≥ 1.0 cm were recorded in 1992, 1994, 1999, 2004, 2008, 2010 and 2015 in a 1-hm ² monitoring plot in the Dinghushan Biosphere Reserve. We quantified the long-term changes over this 24-year study period by species composition, biological diversity, aboveground biomass, DBH frequency table, and stand density by species.

Important findings Important findings From 1992 to 2015, the stand density increased by 42.7% while the total biomass decreased by 5.1%. The β diversity based on biomass and stand density indicated that the diversity increased by 37.4% and 65.6%, respectively, from 1992 to 2015. More importantly, the number of small arbor and shrubs, and smaller trees (DBH < 15 cm) also increased sharply, with major contributions from Aidia canthioides, Macaranga sampsonii and Blastus cochinchinensis. In contrast, the change in stand biomass was more from biomass decrease of Castanopsis chinensis, Schima superba and Cryptocarya concinna, but increase of Gironniera subaequalis and Pterospermum lanceifolium. We conclude that the changes on community composition and structure in the MEBF were significant, which was resulted from a combined influence of succession, changes in climate, and insect outbreaks.

The Stipa bungeana alliance is one of the main steppe types in Eurasian. Endemic to China, the alliance is mainly found in the Loess Plateau and the adjacent areas, but its range of distribution has been noted to decline and become highly fragmented due to conversion to cropland or at unstable successional stages. In this study, we described and analyzed the eco-geographical distribution, community characteristics, and vegetation classification of S. bugneana alliance based on data from 108 plots surveyed during 2013-2019. Results show that S. bungeana alliance is currently distributed in northern Shaanxi, southern Ningxia, eastern and central Gansu, northern Shanxi, the loess hills in the south of Yinshan Mountains and the Erdos Plateau. This alliance occurs mainly on loess soils or kastanozems, along elevation ranging from (1) 631 to 3 174 (4 098) m. Two hundred and fourteen plant species from 37 families and 109 genera were recorded across the 108 plots, with most of them being rare species in the alliance. There are more hemicryptophytes and perennial forbs than other life forms. Xerophytes, especially meso-xerophytes and typical xerophytes, have higher representation in species richness than mesophytes. Among the 10 geographical floristic elements, the East Asia element, the East Palearctic element and the central Asia element were the three dominants. The height, cover, biomass and species richness vary greatly across the plots because those variables are highly related to the moisture and disturbance intensity of the habitats. Based on China Vegetation Classification System, S. bugneana alliance could be classified into seven association groups and 37 associations.

Aims Shrublands are widely distributed in the North China. Understanding species composition and community assembly of the shrublands has important implications for promoting vegetation restoration in this area. Community phylogenetic structure can reflect community assembly process. In the present study, we explored the distribution patterns, species composition and phylogenetic structure of major shrubland types from North China, and then analyzed the effects of temperature and precipitation on these patterns with the help of the WorldClim dataset.
Methods A total 2 331 plots were setup to survey species composition and phylogenetic structure of major shrubland types in North China. A multiple stepwise regression was used to determine the effects of climatic factors on community phylogenetic structure, and a generalize linear model was used to test the interaction of environmental factors and formation types or vegetation types.
Important findings A total of 570 woody species belonging to 207 genera from 75 families, together with 1 221 herb species belonging to 491 genera from 99 families were recorded during the investigation. Five vegetation types and 195 formation types were identified, and the major formation types were Ostryopsis davidiana formation, Vitex negundo var. heterophylla, Vitex negundo var. heterophylla + Hippophae rhamnoides and Hippophae rhamnoides formation. The species richness of herb layer was higher than that of shrub layer. The phylogenetic structure was over-dispersed for herb layer and was convergent for shrub layer. The phylogenetic structure differed remarkable among different vegetation types. The phylogenetic structures of both shrub and herb layers were significantly correlated with climatic factors, and the interaction of climate factors and vegetation types or formation types as well. Our results indicates that large scale variation of climatic factors regulate community phylogenetic structure of different layers in shrub community, and the effects depend on vegetation types and formation types.

Aims Helianthemum songaricum is an ancient Mediterranean remnant plant species endemic to central Asia, and it is a dominant species of a unique desert community in west Erdos, Nei Mongol, China. We studied the distributions, classification and characteristics of the H. songaricum communities.
Methods We collected species composition for 18 plots from literatures and field investigation during the growing seasons of 2016 and 2017. We then applied TWINSPAN to classify community types.
Important findings (1) The H. songaricum communities were primarily distributed in the north and south of the Arbas Mountains and Qianli Ravine in west Erdos, with some in the southern and northern Helan Mountain. (2) In total, 58 seed plant species belonging to 39 genera from 17 families were recorded, including 18 shrub and subshrub, 27 perennial and 13 annual herbaceous species. Super-xerophytes and xerophytes were the two major ecological types, accounting for 26% and 50%, respectively. The Central Asia-Eastern Asia was the major floristic elements, followed by the Palaeo-Mediterranean and the Gobi elements. (3) Based on the life forms and species composition, the H. songaricum communities was divided into three major association groups, i.e., H. songaricum-herbs desert group, H. songaricum-shrubs-herbs desert group and H. songaricum-subshrub desert group, which were further divided into 10 associations.

The Beishan Mountain of Jinhua is located in the northern part of the mid-subtropical region. In vegetation division, this region belongs to the northern sub-zone of mid-subtropical evergreen broad-leaved forest vegetation belt. The vegetation in this mountain is a secondary forest restored from a severe deforestation. It is currently in a rapid process of positive succession. Thus, this region is suitable for studying the dynamics and succession mechanisms of plant communities and the restoration of degraded ecosystems. To further understand the community characteristics of the main vegetation types in Beishan Mountain, we surveyed the main plant communities on its southern slope with a fixed plot method (the plot area is 30 m × 30 m for forests and 20 m × 10 m, 30 m × 10 m for shrubs) based on the internationally accepted forest survey approach used in the survey of dynamic forest plots. The species composition, quantitative characteristics and habitat information of all plant communities were investigated and recorded. The importance values of trees and shrubs were calculated. The community types and their characteristics were analyzed. The spatial distribution maps of the major trees and shrubs in each plot were also drawn. In the present study, detailed community data for 24 sampled plots representing 11 formations were presented (consisting of 21 forest plots and 3 shrub plots).

Three 1-hm² permanent plots were established in the Yaoluoping National Nature Reserve in Anqing of Anhui Province. All trees with diameter at breast height (DBH) ≥ 2 cm were mapped, tagged with aluminum plates of unique numbers, and identified by species. On the basis of the importance value of the canopy and shrub layer, the three plots in Yaoluoping, Diaoguanjing and Anjiping were classified as Castanea seguinii + Lindera glauca deciduous broad-leaf forest community, Platycarya strobilacea + Lindera glauca deciduous broad-leaf forest community, and Platycarya strobilacea + Lindera chienii deciduous broad-leaf forest community, respectively. The three plots were all dominated by deciduous trees with evergreen trees only found in the Diaoguanjing plot. The Diaoguanjing plot was most abundant in species (81), followed by the Anjiping plot (76) and the Diaoguanjing plot (62). The local plant communites are stable and the vegetation is well restored.

Scrubland is the most important vegetation component in Helan Mountains, Nei Mongol, but remians very poorly studied. In order to understand the distribution and growth status of the scrubland resources in this area, the shrub communities in the National Nature Reserve of Helan Mountains were sampled. Using the community data, the characteristics of the community structure were quantitatively analyzed. The results show that the shrub communities along an altitudinal gradient in the National Nature Reserve of Helan Mountains include the following formations: Form. Cotoneaster soongoricus, Form. Syringa oblata, Form. Potentilla parvifolia, Form. Ostryopsis davidiana, Form. Lonicera microphylla, Form. Potentilla glabra, Form. Salix oritrepha and Form. Caragana jubata. Furthermore, we also provide the data on species composition and structures of these montane shrub communities, which could provide insight for the conservation and management of these valuable communities.

Stipa tianschanica var. klemenzii steppe is the most typical formation of desert steppe in China. Based on the primary plots data obtained from fieldworks during the growing seasons from 2010 to 2016 as well as some earlier records, we studied the Stipa tianschanica var. klemenzii steppe across China systematically, including the eco-geographical distributions, community characteristics and classifications. The results showed that S. tianschanica var. klemenzii steppe distributed mainly on the Ulan Qab Plateau and western Xilin Gol Plateau. Due to the arid biotope of S. tianschanica var. klemenzii steppe, quantitative characteristics of the assemblage including height, coverage, biomass and species richness were normally lower than that of most Stipa formations in Eurasian steppe region. Moreover, 165 seed plants belonging to 85 genera and 29 families were recorded in the 80 study sites, in which rare species (occurrence frequency <20%) made up 87% of the total plants while common species and constant species could only be found occasionally. Species with the occurrence frequency exceeding 50% included S. tianschanica var. klemenzii, Convolvulus ammannii, Cleistogenes songorica, Allium tenuissimum. In addition, Hemicryptophyte and therophyte were the two dominant life forms, covering 55% and 20% of the species, respectively. As for the ecological type of water, typical xerophytes accounted for 47% of all species which is followed by super-xerophytes and meso-xerophytes. Middle Asian areal-type and east Palaeo-North areal-type were the two major floristic elements, containing 37% and 26% of the species, respectively. Based on the life forms and dominances of the species within the community, S. tianschanica var. klemenzii steppe in China could be classified into 6 association groups, 29 associations.

Aims The study of the pattern of biomass variations and their drivers along environmental gradients commonly contributes to the understanding of plant’s adaptability to environmental changes, further explains the spatial differences in vegetation and ecosystem processes. We investigated the biomass latitudinal patterns of plant communities and its components and revealed the quantitative relationships of biomass with climatic, soil and community structure as well as species diversity.

Methods In order to analyze the variation patterns of biomass along the latitude gradient and the drivers, we set up a total of 101 plots (4 m × 6 m) across nine region along latitude in the arid valley of southwest China (23.23°-32.26° N), to investigate biomass and species composition of plant communities and its components.

Important findings In the arid valley, the average biomass of community was (17.05 ± 1.09) t·hm^-2, of which the average biomass of shrub, herb and litter were (11.51 ± 1.03), (2.11 ± 0.21) and (3.41 ± 0.34) t·hm^-2, respectively, with each of them accounting for 60.2%, 15.6%, and 24.1% of the community biomass. With the increase of latitude, community biomass increased significantly. Shrub biomass and their proportion also increased significantly, herb biomass and their proportion remained consistent, whereas litter biomass decreased significantly. The changes of shrub dominance and abundance were the main internal factor for vegetation biomass variation along the latitude gradient. Additionally, compared with soil factors, climatic factors had a more significant impact on the biomass changes of communities and its components.

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.

Aims The ecological mechanisms underlying species compositional differences among communities are crucial to understanding and predicting biodiversity changes. One of such mechanisms is the spatial structure independent of ground-level habitat (e.g., soil nutrients and topographic parameters). However, the primary drivers of this spatial structure are still unclear. Forest canopy structure can alter understory microclimates, which in turn influences the spatial structure and species compositional differences. We know little so far about such influence of the forest canopy structure. This gap has hindered our understanding of the ecological mechanisms underlying species compositional difference.

Methods The study was conducted in a 20 hm² evergreen broadleaf forest plot in the Tiantong region, Zhejiang Province, Eastern China. UVA-based LiDAR was used to estimate the high-precision forest canopy structure of the Tiantong plot. The redundancy analysis and the variance decomposition method were used to explore the relative importance of forest canopy structure and other potential factors on community species composition.

Important findings Our research showed that: (1) In the case of excluding the effect of canopy structure, the spatial structure independent of the ground-level habitat was one of the main contributors to the species compositional differences in the Tiantong plot. It explained 25.2%, 28.1%, and 8.0% of the variation in species composition at the scales of 100 m²,and 8.0% of the variation in species composition at the scales of 100 m² Our research showed that: (1) In the case of excluding the effect of canopy structure, the spatial structure independent of the ground-level habitat was one of the main contributors to the species compositional differences in the Tiantong plot. It explained 25.2%, 28.1%, and 8.0% of the variation in species composition at the scales of 100 m², 400 m²,400 m² 400 m², and 2 500 m²,and 2 500 m² and 2 500 m², respectively. (2) Including the effect of forest canopy structure significantly reduced the explanation power of the spatial structure by about 1/3 (26.2%-36.0%). (3) Among canopy structure factors, canopy height had the most significant influence on species composition, followed by internal canopy structure. With the increase of the plot scale, the effects of canopy height decreased while the impacts of internal canopy structure increased. In conclusion, our study demonstrated that canopy structure is one of the main drivers of spatial structure independent of ground-level habitat. Our results also clarify the relative importance of canopy height and internal canopy structure on species composition and provide new perspectives to understand the ecological mechanisms underlying species compositional differences among forest plant communities.

Aims Explore the distribution pattern and the processes controlling the assembly of the Juglans mandshurica dominated forests in North China.
Methods We investigated 84 plots, each with an area of 20 m × 30 m, for the J. mandshurica forests in the North China. We analyzed demography of the J. mandshurica based on its diameters, and applied canonical correspondence analysis (CCA) to explore the relationship between environment and species composition of different formations of the J. mandshurica forests. We then calculated phylogenetic index, i.e., net relatedness index (NRI) and nearest taxonomic index (NTI) and Gaussian Kernel Density Estimation (Gaussian KDE), for each plot to explore the rules controlling community assembly of these forests.
Important findings The population of J. mandshurica is relatively young in the Northern China, with a mean diameters at breast height (DBH) of 5.36 cm. Distribution of J. mandshurica in North China varied significantly with altitude, slope, slope position and human disturbance. Most of the J. mandshurica located at the low part of the massif with lower altitude and less human disturbance. In North China, niche related processes regulated species coexistence of Form. J. mandshurica, with competition controlled the community assembly in Hebei, Shaanxi and Tianjin, while environment filtering dominated in Beijing and Shanxi.

Aims Livestock grazing is one of the most important factors affecting grassland plant diversity. However, the information on the effects of different livestock types and their grazing behaviors on grassland plant diversity and community composition are less available. A better understanding of the changes in plant diversity and community composition in response to the grazing of various livestock types is essential to the management and preservation of grassland biodiversity.

Methods We conducted a grazing experiment in a typical steppe of Nei Mongol to examine the effects of different livestock species (cattle, goat, sheep) and their behaviors (forage selection and grazing aggregation) on plant diversity (i.e., α, β and γ diversity) and community composition.

Important findings Our results showed that: (1) cattle, goat, and sheep grazing all increased plant α, β, and γ diversity at moderate grazing intensity, and the increase was the largest and significant under cattle grazing. (2) Three livestock species all changed community structure; sheep grazing reduced the relative abundance of dominant short grass Cleistogenes squarrosa, which is in contrary to the changes in community structure induced by cattle and goat grazing. (3) Cattle and goat grazing significantly reduced the aboveground biomass of dominant species, including tall grasses Leymus chinensis and Stipa grandis and short grass C. squarrosa, while sheep grazing only decreased that of short grass C. squarrosa. Cattle grazing also had a lower spatial aggregation than that of goat and sheep. (4) Plant diversity decreased with the increase of the aboveground biomass of either tall or short dominant species, indicating that livestock grazing promoted plant species diversity by reducing plant aboveground biomass of dominant species. (5) Plant diversity decreased with the increase in spatial aggregation of livestock grazing, indicating a lower aggregation benefiting plant diversity maintenance. Overall, our study suggests that grazing animal types should be considered along with grazing intensity in the development of grazing management regime for better conservation and sustainable use of the grassland resources.

The main vegetation types of Kalamaili Nature Reserve in east Junggar Basin were investigated in this paper, and based on the data from 54 plot samples, the characteristics of the main desert plant communities from the main vegetation types were quantitatively described. And the results showed that, the vegetation in this reserve can be divided in to 9 major desert plant community types were recognized: Form. Haloxylon ammodendron, Form. Krascheninnikovia ceratoides, Form. Atraphaxis spinosa, Form. Reaumuria songarica, Form. Artemisia songarica, Form. Convolvulus tragacanthoides, Form. Anabasis salsa, Form. Stipa glareosa and Form. Seriphidium terrae-albae, and then, 16 associations were divided from these 9 major community types.

Aims Enclosure is one of the important measures for vegetation restoration of degraded sandy land. Understanding the plant community change of different initial types in long-term state of enclosing is vital for us to understand the vegetation restoration process or re-vegetation in sandy land. This paper aims to analyze the changes of plant communities and its comparative responses to long-term enclosure (2005-2017) of mobile dunes (enclosed in 2005), fixed dunes (enclosed in 1985) and sandy grassland (enclosed in 1997), in relation to soil seed bank, soil nutrient and precipitation and air temperature.
Methods The species composition, height, coverage and above-ground biomass were measured by quadrats in every year during 2005-2017. The soil organic carbon, soil nutrient and soil seed bank were measured by soil cores from the above quadrats in 2008 and 2017. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to explore the relationship between plant community species composition and soil seed bank soil nutrients and soil moisture.
Important findings The results showed that the vegetation coverage and community species richness of mobile dune was significantly increased, but the community biomass had no obvious trend. The biomass of fixed dune community, shrubs, semi-shrubs and the perennial legume functional group dominances decreased significantly, but the dominance of the annual and perennial forbs increased significantly. The annual forbs were the dominant functional group, and community species richness and perennial grass dominances decreased significantly. The soil seed bank had no remarkable change in the three enclosed sandy land communities during 2008-2017, while the seed richness significantly increased in mobile dunes, and that of the fixed dunes and grassland presented downward trends. The soil available nitrogen and available phosphorus were increased significantly. Regression analysis showed the annual variation of plant community biomass was significantly affected by air temperature and precipitation, but there was a little effect on the inter-annual variation of plant community biomass and species richness. Detrended correspondence analysis (DCA) displayed that there was a high similarity between soil seed bank and plant community, and typical correlation analysis (CCA) results showed that grassland community species composition was closely related to soil nutrients. However, fixed dune community species composition was mainly related to soil moisture. In summary, the fixed dune plant community enclosed for 33 years and the sandy grassland plant community enclosed for 21 years present degraded trends, while the mobile dune plant community enclosed for 11 years is slowly recovering, thus, long-term enclosure is not always conducive to the restoration of degraded sandy land vegetation. We suggested that the influence of degradation degree of vegetation, soil nutrients and moisture, soil seed bank and precipitation should be synthetically considered when we set the duration of enclosure for restoration.