Arid and semi-arid ecosystem areas, which constitute an important component of the global land surface, act to regulate the long-term trend and interannual variations in global carbon and water cycles. Previous studies on the mechanisms underlying ecosystem carbon and water cycling and the development of relevant data products focus primarily on forest, grassland, and cropland ecosystems, with few research attention given to semi-arid shrublands. This research gap hinders the evaluation and projection of ecosystem functions at the regional scale. Since 2011, we used the eddy covariance technique to make continuous in situ measurements of carbon, water and heat fluxes in a shrubland ecosystem at Yanchi Research Station, the Mau Us Sandy Land. Data processing steps mainly included data collection, post-processing of raw data, quality control, gap-filling and carbon flux partitioning. We produced flux and micro-meteorological datasets at half-hourly, daily, monthly, and annual temporal resolutions for the years 2012-2016, and analyzed the overall quality of the datasets in terms of the proportion of valid data and the energy balance closure of flux measurements. Results showed: (1) After quality control, the proportion of valid data for half-hour net ecosystem CO2 exchange (NEE), latent heat flux (LE), and sensible heat flux (Hs) was 56.23%-62.19%, 79.40%-94.12%, and 77.56%-91.27%, respectively. (2) Annual and monthly energy balance ratio ranged 0.78-0.83 and 0.59-1.19, respectively. (3) The energy balance closure estimated using the “ordinary least squares” regression method showed that the interannual and seasonal variations in the slope of regression curves varied with a range of 0.73-0.79 at interannual scale and 0.73-0.92 at seasonal scale, respectively. These results indicate that our datasets have a high proportion of valid data and a reasonable energy balance closure, and thus can be used in studies related to ecosystem processes and functions at varing spatio-temporal scales.
Caryopteris mongholica is a key protected wildflower plant distributed in typical steppe, desertified steppe and desert areas. But there is a lack of research on its community characteristics and classification. This paper aims to study the distribution, characteristics and classification of C. mongholica in northern China and provide a reference for further protection and management. From 2018 to 2021, a total of 40 representative C. mongholica sites were selected in northern China, and their community characteristics were studied using the sample plot survey method. Results showed: (1) Caryopteris mongholica is concentrated in the eastern, central and western of Nei Mongol Plateau, the northern Loess Plateau, Hexi Corridor, Qilian Mountains and other northwest temperate desert or steppe areas in China, and is often the dominant or associated species in the communities. (2) According to the survey of 40 sample sites, a total of 149 species of seed plants were recorded, belonging to 107 genera of 37 families, among which 31 communities with C. mongholica as construction or dominant species and 140 species of seed plants were recorded, mainly Compositae, Leguminosae and Gramineae. Among them, 39 species were shrubs, dwarf- and semi-shrubs, 76 species were perennial herbs and 24 species were annuals and biennials. In the classification of species presence, 87.94% were occasional species with frequency distribution less than 20%. Wide-range xerophytes occupied the advantage (63.12%) in the water ecological types. Middle Asia elements (26.24%) were the major floristic geographic elements. (3) Based on the life form and dominance of species, the 31 C. mongholica communities were divided into 3 association groups, C. mongholica - herb association group, C. mongholica + shrub - herb association group and C. mongholica + shrub association group, which were further subdivided into 19 associations. (4) Longitude and annual precipitation significantly influence the distribution of C. mongholica communities and species diversity.
Plot-based data are an important foundation for studying plant community characteristics and compiling vegetation monographs, vegetation map, and vegegraphy. It is the key data source of studies in vegetation ecology. To understand the species composition, community characteristics, and distribution pattern of special plateau vegetation on the Qingzang Plateau (QZP), this study uses the data of 338 sites including 758 plots in different regions of the QZP from 2018 to 2021 to analyze the species composition, floristic characteristics, and vegetation classification of plateau plant communities. A plot-based dataset of plant community on the QZP is then established. The 758 plots have 837 plant species belonging to 279 genera from 65 families in the alpine and temperate vegetation communities. The largest number of species are found in five families: Asteraceae (134 species), Poaceae (88 species), Fabaceae (75 species), Rosaceae (43 species), and Cyperaceae (40 species), as well as five genera: Artemisia (29 species), Pedicularis (27 species), Saussurea (25 species), Astragalus (23 species), and Poa (23 species). The floristic composition is mainly temperate (145 genera) and cosmopolitan (36 genera). The growth forms of the species are mainly herbs (83.51%) and shrubs (10.87%), and the life forms of herbs and woody plants are mainly perennial herbs (88.23%) and deciduous shrubs (83.67%), respectively. A total of 338 sites can be divided into four vegetation formation groups, 10 vegetation formations, 20 vegetation subformations, 78 alliance groups, and 117 alliances, in which 34 are steppe alliances, 33 are meadow alliances, 33 are desert alliances, 14 are shrubland alliances, and 3 are coniferous forest alliances. This dataset covers most of the alpine shrubland, meadow, steppe, desert, and temperate steppe, desert vegetation regions of the QZP. This work provides a solid foundation for exploring the vegetation characteristics and regularity of vegetation zonal differentiation and determining the impacts of climate change and human disturbances on alpine vegetation and their ecological restoration. The dataset also provides a reference for the updating of the next generation of China's vegetation map.
Climate diagram can be used to reflect visually observation data of temperature and precipitation as well as information of weather stations. It is an effective tool for studying the relationship between vegetation and climate. This paper aims to provide the atlas of climate diagrams of the Qingzang Plateau, based on the 30-year averaged observational records of national surface weather stations during 1951-1980 and 1981-2010, respectively, in order to understand the plateau climate feature of every vegetation region and to further explore the vegetation- climate relationships on the plateau. The atlas of climate diagrams of 205 weather stations on the Qingzang Plateau for both the two 30-year periods were produced according to the standard of climate diagrams in Vegetation of China. Results showed that the temperature and precipitation of the Qingzang Plateau were overall low in the whole year but relatively higher in summer, and differed obviously among different vegetation regions. The mean annual temperature and annual precipitation showed an increasing trend from the first 30-year period of 1951-1980 to the later one of 1981-2010. Although the number of weather stations in the western plateau is very sparse, this climate diagram dataset covers every vegetation regions of the plateau surface. This atlas can be used effectively to study the relationships between vegetation and climate, and conveniently to display the climate environment of the plateau.
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.
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.
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.
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.
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.
Pollen record is an essential data for reconstructing paleovegetation and paleoclimate. It is important for the studies of paleoenvironmental evolution, characteristics of paleoclimate change and simulation of paleobiogeochemical cycles from site to regional and global scales. In this paper, we collected and sorted out the pollen data records from published and unpublished Chinese literature between 1960 to 2020. The records included sample numbers, sampling locations (latitude, longitude and altitude of sampling sites), sample types, data sources, data types, surrounding vegetation, references, and pollen taxa, their compositions as well. They were filtered and standardized to integrate a pollen dataset of China. This dataset consists of 4 497 modern pollen sampling sites, including 660 published data from the Chinese Quaternary Pollen Database, 1 763 from early published data and 2 074 from recently collected data, belonging to 772 pollen taxa. The samples were mainly from surface soils (3 332 sites), and the rest were from moss plosters, surface sediments from lakes and the ocean. The sampling sites are widely scattered around China representing different geographical regions and vegetation types: 24.91%. in the temperate desert region, 24.02% in the subtropical evergreen broad-leaved forest region, followed by the temperate grassland region (16.14%) and alpine vegetation region of Qingzang Plateau (15.83%). The data can be divided into the raw data (58%) and numerical data (42%) according to their sources, and grain count (59%) and calculated pollen percentage (41%) by data type as well. The database constructed from the samples over China during the past half-century+ period is, though by far from complete, good representation of most of the areas in China, which can be effective in the reconstruction of past vegetation and climates as modern verification.
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.
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.
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.
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 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.
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).
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.
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 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.
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.
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