Aims The Exochorda giraldii community is a secondary shrubland developed following destruction of warm temperate and deciduous broad-leaved forests. The objective of this study was to explore the distribution and inter-relationships of dominant species in E. giraldii communities in Taiyue Mountains, Shanxi, China.

Methods Based on the vegetation survey data on a 50 m × 50 m plot, point pattern analysis (O-ring) and fractal analyses (including box-counting dimension analysis, information dimension analysis and correlation dimension analysis) were performed to determine the spatial patterns of dominant species in a E. giraldiicommunity.

Important findings In the E. giraldii community, most of the dominant species showed the characteristics of aggregated distribution at smaller scales. However, Periploca sepium and Spiraea salicifolia showed an aggregation distribution at all scales. With increases in scale, the distributions of E. giraldii and Forsythia suspensa changed from aggregation to random and to uniform. Based on the point pattern analysis, the dominant species in the E. giraldii community showed aggregation distribution characteristics at different scales. The box-counting dimension analysis indicated that the ability of dominant species to occupy the space in the E. giraldii community was in the order of E. giraldii > F. suspensa > S. salicifolia > P. sepium. The information dimension analysis indicated that the degree of changes in pattern intensity of dominant species with scale in the E. giraldii community was in the order of P. sepium > S. salicifolia > E. giraldii > F. suspensa. The correlation dimension analysis showed that the spatial correlations of dominant species in the E. giraldii community was in the order of P. sepium > E. giraldii > F. suspensa > S. salicifolia. On a smaller scale, the E. giraldii population showed aggregated distribution; the F. suspensa population and the E. giraldii population had a positive correlation; the S. salicifolia population and the E. giraldii population had a positive correlation; the P. sepium population and the E. giraldii population had a negative correlation. Point pattern analysis and fractal analyses produced consistent results, revealing the spatial distribution patterns of secondary shrubs following destruction of the warm temperate and deciduous broad-leaved forests.

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.

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.

The endangerment mechanism of rare conifer species is a very critical problem in conservation biodiversity. Thus, the studies on the protection of the rare and endangered coniferous trees have received extensive attention. The objective of this study was to understand the survival and distribution of the rare coniferous tree species in natural forests of the Poyang Lake Basin. Field investigations on plant communities were conducted in 21 plots from Oct. 2014 to Oct. 2015. These plots were distributed in the Nanling Mountains, Luoxiao Mountains, Wuyi Mountains, Huangshan Mountains, and Jiuling Mountain. The dimensions of each plot were 20 m × 20 m. Community species composition and quantitative characteristics in each plot were recorded. The importance values of trees, shrubs and herbs were computed, respectively. The community types and structural properties were analyzed. A total of 23 sets of community sampling data were obtained in details. A number of 11 species of rare conifers were found in 14 different formations. Rare conifer trees mainly occurred in the communities as co-edificatos or companion species. The formations included Form. Taxus wallichiana var. mairei, Form. Pseudotsuga sinensis, Form. Fokienia hodginsii and Form. Torreya grandis, where the dominant species was coniferous trees. In conclusion, our study provides valuable field investigation data of rare coniferous in Poyang Lake basin, which could provide insight into the protection and management of these species.

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.

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.

Aims Based on the dataset of a broad-leaved Korean pine forest in Jiaohe, Jilin Province, this research compared the influences of species diversity and community structure on productivity. We aim to explain the relationship between diversity and productivity for better forest management.
Methods We used the data of 10 973 woody-plants in a 11.76 hm² large sample plot and analyzed the correlations between 7 different indices of species diversity or community structure and productivity. Structural equation model was used to compare the effects of species diversity and community structure on productivity.
Important findings The results showed that: (1) Both species diversity and community structure had significant effects on productivity when they were considered separately in linear regression analysis, i.e. species evenness was negatively correlated with productivity, the Shannon index of community structure was positively correlated with productivity and the Gini index was negatively correlated with productivity. (2) In the structural equation model, when simultaneously considered, community structure had stronger influence on productivity than species diversity. Our research suggests that, the effects of community structure on productivity are greater than species diversity and it is important to increase community structure complexity to improve forest productivity during forest management.

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.

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.

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.

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 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.

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.

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 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 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.

Aims Many competing theories seek to identify the mechanisms behind the community assembly. Niche theory and neutral theory are among the two most competing mechanisms. Exploring factors controlling the patterns of β-diversity is an approach to reveal the underlying mechanisms of community assembly. In this paper, we aim to reveal the β-diversity pattern of understory in planted forests of the central Loess Plateau and to evaluate the relative influences of deterministic (environmental filtering) and stochastic (dispersal limitation) processes on the community assembly.
Methods We sampled in total 107 sites of planted forests spatially spreading over the central Loess Plateau. In each site, three plots (10 m × 10 m) were randomly designed each at a distance of about 50 m. The floristic composition, community structure, and environmental conditions were investigated in each plot. We calculated the dissimilarity (β_sim) of species composition, geographic distance and environmental divergence for each of the 5 671 site pairs. We used random forest (RF) to quantify the influence of the selected factors on species composition, and distance-based multivariate regression method (MRM) to fit the relationship between dissimilarity, geographic distance and environmental divergence. To quantify how and in what extent the environmental filtering and the dispersal limitation influence the species composition among sites, we performed the principle coordinates of neighbor matrices (PCNM) and distance-based RDA (db-RDA) to select the pronounced independent variables. We then partitioned the variance into three parts, namely, 1) independent contributions of geographic distance; 2) independent contributions of environmental divergence; and 3) the joint contribution of both.
Important findings The community similarity declined with increasing geographical distance and environmental divergence. Geographical distance and environmental divergence together explained 47.8% of variance in the dissimilarity in species composition. The spatial variables accounted for 14.1%, while the environmental variables accounted for another 9.8% of the variance in dissimilarity of species composition. Annual precipitation and basal area of trees are the two most important environmental factors influencing the pattern of dissimilarity of species composition. These results implied that both environmental filtering and the dispersal limitation play important roles in shaping the community assembly of the herbaceous layers of planted forests in the central Loess Plateau.

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.

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 community assembly mechanisms are among the focal topics in ecological studies. In Changbai Mountains Nature Reserve, there is an intact primary broadleaved-Korean pine forest ecosystem. With increasing loss of species diversity in recent years, study that explores the community assembly mechanisms in this region is particularly important.

Methods This study was conducted in three large permanent plots, each of the size 5.2 hm ², along suessional stages (secondary poplar and birch mixed forest, PBF; secondary mixed conifer and broad-leaved forest, CBF; and primary Tilia amurensis-Pinus koraiensis mixed forest, TKF) in Changbai Mountains. Six functional traits of major tree species were measured, including leaf area, specific leaf area, leaf thickness, leaf nitrogen content, leaf phosphorus content, and maximum tree height. Changes in the spatial values of community traints were analyzed at different spatial scales (5 m × 5 m, 10 m × 10 m, 20 m × 20 m, 30 m × 30 m, 40 m × 40 m, 50 m × 50 m and 60 m × 60 m). By comparing the observed values with expected values of null models, the community assembly mechanisms in temperate forests of Changbai Mountains were explored.

Important findings Results show that the size of species pool has an important impact on the outcome; in a larger species pool, the environmental filtration has a significant impact. At the plot level and for early and intermediate stages of succession, the observed spatial values of community traits do not significantly differ from the expected values. At the late successional stage, the observed spatial values of community traits were greater than the expected values. The analysis of multiple community functional diversity indices shows that the combined processes of habitat filtring and competitive exclusion are the main determinants of the species composition of the climax community in this region. In the early successional stage, large numbers of species are immigrated, and there are strong resource competitions among the species within a community. With progressing succession, some species are excluded, species maintained in the community show significant niche differentiations, and competition is the main mechanism species coexistence.

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).

Aims The study of species diversity patterns is useful in understanding community structure and resource allocation patterns in the succession process in alpine meadows. The present study aims to explore: 1) the changes in community species-abundance relationships in alpine meadows of the Qinghai-Xizang Plateau with mountain slopes; and 2) the difference between the abundances of common and rare species, and their roles in the ecological mechanisms. Methods Field investigation was carried out in alpine meadows of the Qinghai-Xizang Plateau followed by lab analyses in Lanzhou. RAD was used to analyze the difference in environmental factors and plant communities among different slope aspects. Important findings Soil water content increased gradually from the south to north slopes (from 0.18 g·g ^-1 on the south slope to 0.31 g·g ^-1 on the north slope), while soil temperature and light intensity showed the opposite trends (from 22.33 ℃ and 744.15 lx on the south slope to 18.13 ℃ and 681.93 lx on the north slope, respectively). The species abundance and species diversity increased, while the slope of species abundance curves decreased from the south to north slopes. Among the six species abundance fitting models, the ecological niche model best explained the species abundance curves followed by the random distribution model. Further analysis showed that the overall resource allocation pattern of species was mainly fixed distribution. In addition, the resource allocation pattern of the rare species was mainly random, while that of the common species was mainly deterministic.

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.

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 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.

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.

The ecological “green-core” area of Changzhutan urban cluster is located in the center of red soil hilly region of Southern China, and the northern vegetation sub-zone of mid-subtropical evergreen broad-leaved forests. In this area, the vegetation is dominated by secondary forests, and the vegetation types are diverse. It is representative of the current vegetation in red soil hilly region of South China, and hance can provide a good platform for the research of regional vegetation succession dynamics and vegetation restoration. We set up 50 plots with a unified and standardized method, and then the species composition, quantitative characteristics, and habitat information of the main vegetation types in the area were investigated. The importance values of species in the tree layer, shrub layer and herb layer were calculated, and the vegetation type of each community were identified and named according to the compilation and research standard of Vegegraphy of China. The community species composition and characteristics were described, and the original data of 50 plots divided into 10 vegetation formations, 22 alliances and 33 associations were provided, including 43 forest plots, 5 shrub plots, 1 grassland plot and 1 swamp plot.

Dashiwei Tiankeng group is rich in plant diversity resources. In order to further understand the plant community characteristics of the Dashiwei Tiankeng group, a total of 25 sample plots were set up in different positions (mouth pit, waist pit, bottom pit) and outside the pit in the Dashiwei Tiankeng group. 269 species of vascular plants belonging to 176 genera and 89 families were investigated by the sampling method, and Lauraceae, Rosaceae, Urticaceae and so on are the most abundant families in the community. The stratification is obvious and the distribution of dominant species was more uniform in each layer of the community. Among them,Manglietia aromatica, Choerospondias axillaris, Handeliodendron bodinieri were dominant species in the tree layer; Metapanax davidii, Itea yunnanensi were dominant species in the shrub layer, and the dominant herb layer is Elatostema. The seasonal phase is obvious of the community. It is mainly evergreen and deciduous broad-leaved mixed forest, with the evergreen broad-leaved forest at the bottom pit and the deciduous broad-leaved forest at the edge of mouth pit. The life form spectrum of the community is 55.76% for phanerophytes, 29.74% for aboveground plants, 6.69% for aboveground plants, 5.21% for cryptophytes and 2.60% for annual plants. The characteristics of the community types, composition and structure of Tiankeng were analyzed in this paper, which provided basic information for studies of plant communities in Dashiwei.

Aims Understanding the population quantity and distribution of a drought-resistant plant, Keteleeria davidiana, can assist the protection of this rare and endangered species.
Methods The K. davidiana forest communities were investigated in dry land of 6 townships in Xinping County, Yunnan Province, in three 20 m × 20 m plots for each township, and analyzed for structural characteristics in consideration of species composition and life-forms.
Important findings We found 163 vascular plants belonging to 131 genera and 58 families in the plots with a total area of 7 200 m². The communities are classified into 12 zonal types containing predominantly tropical and endemic species to China, dominated by the tropical components. Trees and shrubs (accounted for 62.58%) are dominant life-forms, followed by perennial herb. Based on the foundation species and life-form, the data of 18 vegetation plots were classified into 3 formations and 17 community types. The analysis of stumpage structure showed that the population structure of K. davidiana tended to recess, and the natural populations are small. If lacks sufficient regeneration seedlings, the K. davidiana trees would decline and diminish from the communities.

The central Guizhou Plateau is located in the center of the karst region of southwestern China. The typical vegetation type is karst mixed evergreen and deciduous broad-leaved forests on this distinct landform. Due to human disturbances, the main existing vegetation is secondary vegetation in this region. Based on the primary plot-level data obtained from fieldwork during the growing season from 2007-2020, we systematically studied the community characteristics and the classification of these karst forests. The results showed that the typical karst forests are co-dominated by evergreen trees (e.g., Cyclobalanopsis, Itea, Lithocarpus, Machilus and Cinnamomum species) and deciduous trees (e.g., Platycarya, Carpinus, Celtis and Quercus species). Moreover, 585 vascular plants belonging to 318 genera and 124 families were recorded in the 86 forest plots, among which there were 65 ferns species belonging to 27 genera and 11 families, and 520 angiosperm species belonging to 291 genera and 113 families. The karst forests show high diversities of species composition and community type. Based on the dominance principle, these karst forests were classified into 11 alliance groups, 44 alliances and 83 associations.

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 karst forests of Junzi Mountain are within the territory of Shizong County in east Yunnan Province, belonging to the vegetation zoning of semi-humid evergreen broadleaf forests and Pinus yunnanensis forests of the mid- and eastern Yunnan Plateaus. These forests are predominantly secondary and typical representatives of the forest remnants in the eastern edge of the zonal vegetation. In order to determine the vegetation types and community characteristics of the karst forests in Junzi Mountain, systematic plot surveys were carried out for species composition, quantitative characteristics and habitat information of all plant communities. Based on analysis of the survey data from 29 plots and the revised vegetation classification system of China, these karst forests could be categorized into 4 vegetation formations, 16 alliances and 27 associations. This paper presents descriptions on the characteristics for each association and provides the original data from all survey plots.

Amygdalus mongolica is a kind of rare and endangered plant in China, which has high academic value and diagnostic significance for the evolution of the flora and the biodiversity and stability of the ecosystem. The 14 Amygdalus mongolica sites were set up to investigate its community composition in Ningxia. The results showed that the 74 plant species in Amygdalus mongolica sites in Ningxia belong to 53 genera from 28 families were recorded, including 2 trees, 21 shrubs, 11 subshrubs, 36 perennial herbs and 4 annual herbs. TWINSPAN divides 14 Amygdalus mongolica sites into Amygdalus mongolica - Herbs Desert, Amygdalus mongolica - Subshrubs Desert Associations Group and Amygdalus mongolica - Stipa tianschanica var. gobica, Amygdalus mongolica - Oxytropis aciphylla, Amygdalus mongolica - Stipa breviflora, Amygdalus mongolica - Ajania achilleoides, Amygdalus mongolica - Elymus alashanicus, Amygdalus mongolica - Ajania achilleoides + Stipa breviflora 6 Associations. Our study will provide basic data for the protection, utilization and compilation of vegetation of Amygdalus mongolica.

Ephedra rhytidosperma is an endemic and endangered plant in East Alxa, and its community is one of the unique desert plant communities in the Helan Mountain. In this paper, we investigated 16 plots of the E. rhytidosperma community in 2019 and analyzed its flora characteristics, applied TWINSPAN to classify community types. Results showed that: 1) The species composition of E. rhytidosperma community was dominated by Gramineae, Compositae, Leguminosae and Zygophyllaceae, belonging to 13 families, 24 genera and 27 species. 2) The main life forms of E. rhytidosperma community were perennial herbs (44.44%) and shrubs (29.63%); the main floristic geographic elements were Palaeo-Mediterranean element (44.44%) and East Asia element (33.33%); the main ecological types of water were xerophyes (40.74%) and super-xerophytes (37.04%). 3) Based on the life forms and species composition, the E. rhytidosperma communities were divided into two major Association Groups. Ephedra rhytidosperma - Semi-Shrub Desert and Ephedra rhytidosperma - Herb Desert, which were further divided into 3 Associations: Ephedra rhytidosperma - Convolvulus tragacanthoides - Lespedeza davurica Semi-Shrub and Herb Desert, Ephedra rhytidosperma - Convolvulus tragacanthoides - Ptilagrostis pelliotii Semi-Shrub and Herb Desert and Ephedra rhytidosperma - Ptilagrostis pelliotii Semi-Shrub and Herb Desert.

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.