Herbaceous plant is an important component of forest ecosystem. The interspecific associations of dominant herbaceous plants and the relationships between environmental factors and herbaceous plant communities were investigated in Pinus yunnanensis forest in the western suburbs of Chuxiong City, thereby providing basic information for maintaining the structure and function of forests ecosystem in the region. The relationship among 8 dominant herbaceous species was comprehensively analyzed using niche width, niche overlap, variance ratio method, Chi-square test, connection coefficient, Spearman’s rank correlation coefficient and M. Godron stability analysis. The relationships between environmental factors and dominant herbaceous species were investigated by redundancy analysis (RDA). The results showed that, (1) most of the dominant herbaceous plants had narrow niche width, and Schizachyrium brevifolium (Sw) Nees ex Buse had a wider niche breadth than other species. The niche overlap of most dominant herbaceous species were low. (2) The aggression of Schizachyrium brevifolium (Sw) Nees ex Buse was the strongest, whereas the other seven dominant species were declining populations. (3) The overall interspecific associations were significantly negative associations among all the dominant herbaceous species, and the interspecific association was not significantly correlative in most of the species pairs. The result for the community stability (47.42/52.58) was distinct to the value of 20/80. (4) By RDA analysis, soil pH, slope aspect, soil organic matter, soil electric conductivity and total phosphorus were significant factors affecting the distribution of herbaceous species. Based on the analyses mentioned above, we found that the herbaceous species were highly independent in our study area. The whole dominant herbaceous community was unstable, and the community was still in the early stage of succession. The structure of herb layer can be adjusted according to interspecific association, niche characteristics, and environmental factors in future forest management activities, in order to maintain and improve the stability of herbaceous plant community.

In order to provide a scientific basis for the conservation of Pseudotsuga sinensis community and the protection of Karst mountain biodiversity, the effects of altitude on the species diversity of P. sinensis community were studied. The species composition of different altitudinal gradients of P. sinensis community and the floristic characteristics were analyzed using the sampling survey method, to explore the altitudinal gradient pattern and maintenance mechanism of the species diversity of the P. sinensis community. There were 124 species of seed plants belonging to 95 genera, 50 families in the sample plot. The geographical composition of plant genera in the community was complex and diverse, with obvious temperate properties. The species richness index, Shannon Wiener diversity index, Simpson dominance index and Pielou evenness index of shrub layer and herb layer all showed a single peak curve. Furthermore, on the altitudinal gradient, they presented significant difference, but the Pielou evenness index of shrub layer was not significant (P<0.05). The variation trend of β diversity index between adjacent altitudes was different,with Sørenson index of the shrub layer species showed a double peak curve, whereas that of the herb layer species with a single peak curve, and the Cody index of the shrub layer and the herb layer both showed a single peak curve. With the increase of altitude difference, the Sørenson index of herbaceous layer species gradually decreased, while the other β diversity indexes of the shrub layer and the herb layer presented no obvious change rule. On the whole, the difference in water and heat conditions caused by relative altitude was the main factor affecting the vertical distribution pattern of species diversity in karst mountains areas. Among them, the species diversity under P. sinensis forests in the middle altitude zone was the highest, which was of great significance for the protection and maintenance of germplasm resources of P. sinensis, and also had important guiding significance for the management of plant communities and the maintenance of ecosystem in karst mountains areas.

With its unique geographical environment and climatic characteristics, Xinjiang has become a genetic treasure house of wild animals and plants. The complex habitat has bred many unique animal populations. So exploring the spatial differences in species richness not only enriches the methodological research of biodiversity, but also it is of practical significance to maintain the ecological stability of the region and the sustainable development of the ecological environment. Therefore, based on the 10 km×10 km species vector data of birds and mammals in Xinjiang, combined with other multi-source data, the spatial distribution of species in Xinjiang was mapped and analyzed. And the data after vector to grid were used for reclassification and spatial statistics. The spatial patterns of richness and their core areas were analyzed. Then, through spatial analysis techniques such as matrix analysis, we have deeply explored the differences in the spatial distribution between birds and mammals. The results show that, (1) The richness in northern Xinjiang is higher than that in southern Xinjiang, and the abundance of birds is higher than that of mammals. The H-H areas are mainly in the Altai Mountains and the north and south of the Tianshan, accounting for 5.46% of the entire Xinjiang region, while the L-L areas are mainly in the southwestern Pamirs, accounting for 2.85%. There is a polarization difference between the two species in the same range. The H-L and L-H areas only account for 2.99%, and they are mainly located in the central region, and the regional distribution of the remaining combination modes is relatively scattered. (2) At different altitudes, the species richness is significantly different. Due to the single ecosystem where the altitude is lower than 0 m or higher than 4000 m, the species is less. The ecosystems within the height of 1000?2500 m are the most abundant, which is the appropriate altitudes for birds and mammals to grow. At the same time, the species is not only rich and diverse, but the difference in richness between the two is also the most complicated.

Grassland desertification has become an urgent environmental issue, which negatively affects forage production and environmental conditions for residents living in grassland areas. Current researches on desertified grassland have been mainly focused on changes in vegetation and soil properties, while the changed relationships among species caused by desertification have been rarely investigated. Based on the classic niche theory, this study used space as a surrogate of time series to assess the changed characteristics of plant communities along the desertification gradient in alpine grasslands. The species composition, niche width, and niche overlap (O) were analyzed along the desertification gradients, as well as the resource utilization and ecological adaptability of plant populations. The research findings can provide scientific guidelines for revealing the mechanism maintaining plant diversity in alpine grasslands and for restoring desertified grassland vegetation of the Qinghai-Tibet Plateau. Along the desertification gradient, community coverage and aboveground biomass showed gradually decreasing trends. However, the highest species richness, Simpson index, and Shannon-Wiener index appeared in the light desertification gradient end, and then showed significant decreasing trends. The Pielou index did not differ significantly among the desertification gradients. The importance value showed that significant differences occurred in community structure among the desertification gradients. Correlation analysis found that species niche width along the desertification gradient displayed a saturation curve with the importance values. Along the increasing desertification, the number of plant population with high niche overlap (>0.9) and partial overlap (0.5<O≤0.9) gradually decreased, while the number of moderate overlap (≤0.5) did not change. This means that the decrease in species number caused by desertification can reduce the competition for resource utilization among plant species. Accompanied by weakened soil nutrients, resources utilization among plant populations is diversified in order to reduce competition for limited resources.

Taking ten typical urban forest communities in Guiyang as research objects, based on field sampling survey and laboratory test, the differences of plant diversity and soil physicochemical properties in different urban forest communities in Guiyang were analyzed by one-way analysis of variance. The effects of soil physicochemical properties on plant diversity and species distribution in different urban forest communities in Guiyang city were studied by using redundancy analysis and canonical correspondence analysis, aiming to provide important scientific basis and theoretical support for ecological protection and maintenance of urban forest plant diversity in Guiyang city and even Karst urban forest in southwest China. The results showed that: (1) There are 61 families, 107 genera, and 124 species of vascular plants totally. The plant species with the highest important values were different at different layers in different types of urban forests. The composition of the Mixed Plantation of Ligustrum lucidum and Betula alnoides mixed forest the most abundant, and the Pinus massoniana forest is the lowest. (2) The Shannon-Wiener index, richness index, and Pielou evenness index of various urban forest communities are the highest in Ligustrum lucidum mixed forest, and the diversity indexes of the Pinus massoniana forest is the lowest. There is a significant difference between the diversity indexes of the Pinus massoniana forest and the diversity indexes of Ligustrum lucidum mixed forest. The diversity index changes of shrub layer and community were similar, the Shannon-Wiener index and richness index of herb layer were the highest in Pinus massoniana and Pinus armandii mixed forest while the Pielou evenness index was the highest in Cinnamomum camphorum forest, and the three indexes were the lowest in Pinus massoniana forest, while the change of Simpson dominance index was opposite to the other three indexes. (3) Different urban forest communities of soil pH, total phosphorus, total potassium, available potassium, available phosphorus, bulk density has significant difference, but no significant difference of total nitrogen, available nitrogen, organic matter, among them, the soil pH on species distribution and the shrub layer has a significant influence species diversity, soil bulk density has significant effect on species distribution and herbaceous species diversity, Soil available potassium had no significant effect on species distribution, but had significant effect on community species diversity, while soil organic matter and total phosphorus, were opposite.

Root rot seriously restricts the development of Lycium barbarum industry. The changes of soil microbial diversity and species composition are closely related to the occurrence of plant root rot. It is essential to know the relationship between the occurrence of root rot of Lycium barbarum with the microbial composition in rhizoplane, rhizosphere and root zone soil. The 16S rDNA “V3+V4” region and ITS1 fragment of the total soil DNA from the rhizoplane, rhizosphere and root zone of the diseased and healthy plants were sequenced using Illumina MiSeq high-throughput sequencing technology. Then the sequencing results were quality controlled and aligned with the relevant databases for annotation and analysis. The dominant phylum and genus in the fungal community were Ascomycota and Fusarium, respectively. The dominant phyla in the bacterial community were Actinobacteria, Proteobacteria and Chloroflexi. Arthrobacter was the dominant genus, and its abundance in rhizoplane was significantly higher than that in the rhizosphere and root zone soil. The composition or proportion of dominant species in rhizoplane, rhizosphere and root zone were quite different. The fungal communities richness, diversity and evenness in the rhizoplane of healthy plants were higher than that in the diseased plants (P<0.05), and there was no significant difference in α diversity index between the healthy and diseased plants. Functional prediction showed that there was little difference between the healthy and diseased plants in the bacterial community. The functional abundance of Fusarium was higher in the rhizoplane and rhizosphere of the diseased plants than that in the healthy plants. In all, there was great difference of fungal community diversity between the healthy and diseased plants, which has the most significant effect on rhizoplane fungi. Fusarium, the most dominant taxon in the rhizoplane and rhizosphere soils of the diseased plants, had the highest functional abundance. This study mainly discussed the differences of soil microbial community and function between the healthy and the diseased Lycium barbarum of Ningqi-1, which was of great significance to understand the root rot of Lycium barbarum in Ningxia.

The diversity of understory plants is important for the sustainable management of Pinus massoniana plantation. Forest age, as an important structure-factor of the forest, reflects the resistance, integrity and succession of the forest community. Seeds in the forest soil are closely related to the above-ground vegetation. Understanding the understory vegetation is important for restoring plant diversity, improving vegetation structure, and maintaining ecosystem stability of the P. massoniana plantation. Through a combination of typical plot surveys and germination experiments, P. massoniana plantations of four different ages in Shilong Forest Farm of Taizishan, Hubei Province were used as the research objects. The four age-class plantations used in the study were young forests (9 a), middle-aged forests (15 a), mature forest (30 a), and over mature forest (50 a). For the better management of the multi-purpose and sustainable development of P. massoniana plantation, we compared and analyzed the species diversity of its understory vegetation and soil seed bank. The results showed that: (1) There were 69 species of undergrowth herbs and shrubs belonging to 61 genera and 42 families in the four age-classes of the plantation; Photophilous plants dominated in the young forest, while shade-tolerant plants dominated forests of the other three classes; (2) The Margalef (M) index of herbage, shrub and total shrub (herbage and shrub) showed similar trend between the four age-classes. As the forest age increased, M index first increased, then decreased, and finally slightly increased. The M value of the middle-aged forest was the highest; (3) The Shannon Wiener (H), Simpson (D), pieolou (J_SW) and Alatalo (A) indexes of herbage, shrub and total shrub showed different extent of variation but similar trend between different age-classes: increased first and then decreased; The H, D, J_SW and A for herbage and for the total shrub were the highest in the middle-aged forest, indicating diversity of understory plants was the highest in the middle-aged forest; The H, D, J_SW and A for the young forest were the lowest, and were significantly lower than that of the other age-class forests (P<0.05); For the shrub layer, J_SW and A evenness indexes showed similar trend across the four age-classes: Highest in the mature forest, lowest in the over mature forest, but the differences between the age-classes were not statistically significant (P>0.05); (4) The M, H and D indexes of soil seed bank first increased and then decreased as forest age increased, and reached the maximum in mature forest. This trend was similar to that of the plant richness and diversity of understory vegetation. The Jaccard (C_J) and Soresen (C_S) similarity coefficients between the total shrub layer and the soil seed bank of the four age-classes were as follows: 15 a>30 a>50 a>9 a. In summary, the understory plants of middle-aged forest (15 a) are relatively rich, which can maintain the diversity of understory plants of the P. massoniana plantation.

Wetland is a unique natural complex formed by interaction of land and water, which is an important habitat for perching and breeding to wild birds. Moreover, it plays an overwhelmingly crucial function for birds’ migration. However, due to the irrational exploitation under background of urbanization, the loss and degradation of wetland area are fast. Therefore, the investigation of bird diversity has great significance for scientific preservation of birds in Yundonghai National Wetland Park, especially for migratory birds and their rest, breeding and food. The avian diversity in different habitats, namely villages and fish ponds, paddy fields, tidal flat wetlands and lake island, reeds area were monthly investigated from January 2020 to December 2020 by line transects. The dynamics of bird community structure and diversity were also analyzed. The findings are as the followings: (1) A list of 72 bird species containing 12 orders, 32 families and 56 orders of the wetland park was made. Among these,1 species of national class I and 7 species of class II in the List of Key Protected Wild Animals in China, respectively. One critically endangered species (CR) belongs to the IUCN and 5 species were in the Appendices II. Among the 72 bird species, 2 species and 19 species were the dominant and common species, respectively. Most birds belong to Passeriformes, resident birds and insectivorous birds, with 42, 39 and 45 species, respectively. (2) There were significant differences among bird species, quantity, and biomass in different habitats. The bird species was shown in tidal flat wetlands and lake island>paddy>villages and fish ponds>reeds (P<0.01). The bird population was presented in the order of paddy>tidal flat wetlands and lake island>villages and fish ponds>reeds (P<0.05). However, the biomass of birds was demonstrated in tidal flat wetlands and lake island>paddy>villages and fish ponds> reeds (P< 0.01). (3) There were significant differences in bird species, quantity and biomass among different seasons. The declining trends of bird species, quantity and biomass were in the orders of winter>fall>spring>summer, spring>winter>fall>summer, and spring>fall>summer>winter, respectively. (4) The Shannon Wiener index, Pielou evenness index and Simpson index were higher in the tidal flat wetlands than the other habitats, but the lowest in the paddy. The Margalef index was the highest in the tidal flat wetlands and lake island, and the lowest in the Villages and fish ponds. The Shannon Wiener index and Margalef index were the highest in the winter, and the lowest in the summer. However, the Pielou evenness index was the highest in the spring, and the lowest in the winter. The results manifested that Yundonghai National Wetland Park was rich in bird resources and played an important role in the ecological protection of migratory birds and the maintenance of bird diversity.

Soil animals are very sensitive to soil physical and chemical environmental changes, and the community structure and diversity of soil animals can be used to indicate the degree of soil heavy metal pollution in the tungsten tailings area. This paper selected the tea garden habitats with different pollution levels in the lower reaches of the tungsten mining area as the research object, using sample methods to systematically investigate the community structure and diversity of soil animals. In the same time, we also collected soil samples in order to determine soil physical and chemical environmental factors. The difference of soil animal community in three tea gardens was calculated by using NMDS, ANOSIM. Moreover, the relationship of soil animal community with soil environmental factors and heavy metal pollution index was analyzed using RDA and correlation analysis. The results showed that the number of individuals, taxa groups, species richness, and diversity index of soil animals in unpolluted tea gardens were significantly higher than those of contaminated tea gardens I and II, while the number of individuals, group numbers, and species richness of soil animals in polluted tea garden II were also significantly higher than that in the polluted tea garden I. Evenness index of soil animal community in the unpolluted tea garden was significantly higher than that in the polluted tea garden II. Soil organic matter was the main environmental factor affecting the distribution of soil animals (51.42%), followed by total nitrogen (9.08%), total phosphorus (11.21%), available phosphorus and total potassium (9.61%). It positively correlated with the number of individual and groups of soil animals. Further analysis found that heavy metals such as Ni, Cd, As, and Cu were the main pollution factors in tea gardens, which significantly reduced the soil organic matter (63.8% and 58.5%), total nitrogen (61.7% and 65%) and available phosphorous (55.9% and 8.8%) content in the tea gardens I and II. Ni, Cd and As were the main toxic factors that limited the distribution of soil animal communities in tea gardens, which explained 46.55%, 14.14%, and 9.83% of the variation of soil animals, respectively. Heavy metal pollution reduced the availability of soil nutrients in tea gardens, and the heavy metal pollution index limited the growth of the number of individuals and groups of soil animals. The richness index, diversity index and dominance index of the soil animal community decreased as the increaseing degree of heavy metal pollution.

The purpose of this paper is to improve management and ecological services of natural forests by exploring the community characteristics and their correlation relationship. In this study, the diameter breast height (DBH), diameter ground height (DGH), canopy diameter (CD), fraction cover (FC) of trees, shrub and herb were investigated for three typical communities i.e. pure larch forest (Larix gmelinii), birch secondary forest (Betula platyphylla), mixed larch-birch forest, located in Zhalantun in Daxinganling Mountains. The community characteristics including richness index, diversity index and evenness index were calculated and analyzed by PCA method. The results showed that (1) height and DBH of tree, DBG and FC of shrub layer in pure larch forest were largest. The herb characteristics of among three natural forests were not significantly different (P>0.05). (2) Corylus heterophylla and Spiraea pubescens were more important than the other shrub species in pure larch forest and mixed larch-birch forest. There was only one shrub species i.e. Salix hsinganica in birch secondary forest. Carex chinganensis was the dominant species among three natural forest. (3) The richness index, Simpson index and Shannon-Wiener index of tree and shrub were: mixed larch-birch forest>larch forest>birch secondary forest. The richness index of herb was largest for larch forest, while Simpson index and Shannon-Wiener index of herb were largest for birch secondary forest. Meantime, the Pielou index of tree, shrub and herb was the largest for mixed larch-birch forest. (4) PCA result showed that the diversity index and evenness of shrub increased and the herb diversity decreased when the canopy closure, height, DBH of trees and FC, height and DGH of shrub increased. We conclude that tree canopy density and shrub coverage, height and DGH are the main affecting factors of plant diversity. There is the correlation relationship between community characteristics and plant diversity.

Populus euphratica Oliv. is a beneficial species in desert riparian forests, and it plays an important role in maintaining the stability of desert riparian ecosystems and inhibiting desertification. To understand the variation patterns in Populus euphratica community structure and diversity characteristics along riverbanks in an extremely arid desert riparian area, the natural distribution of the Populus euphratica forest in the downstream desert riparian area of the Heihe River was selected as the observation sampling site, and 9 sites were vertically set along the riverbank to analyse the species composition, structure, flora and diversity characteristics of the Populus euphratica community along the river gradient. The results showed that the species diversity of the Populus euphratica community was low, with 9 species belonging to 7 families and 9 genera. Populus euphratica was the absolute dominant species in the community (the importance value was 0.61-0.90) and the dominant beneficial species. Plant flora was minimal, with a high proportion of single species families and genera, obvious temperate attributes, and a close geographical connection with ancient Mediterranean components. With increasing distance along the riverbank, the plant community structure transitioned from tree-shrub-grass to tree-grass. The coverage of the plant community increased and then decreased significantly, reaching a maximum of 74.33% 650 m away from the riverbank, and shrub layer coverage was generally lower than tree layer and herb layer coverage. The diversity indices of the Populus euphratica community were low, and the maximum values of the Patrick index, Simpson index, Shannon-Wiener index and Pielou index were 7, 0.66, 1.31 and 0.81, respectively. α diversity indices increased and then decreased along the river gradient, reaching a peak between 650-800 m away from the river, and the Pielou index did not change significantly. The Cody index peaked at 650-800 m and 800-950 m from the riverbank, while the Sørensen index was low. These results indicated that in this region, the β diversity of the Populus euphratica community was the highest, and the heterogeneity of the Populus euphratica community was high. In the downstream desert riparian area of the Heihe River, the variations in the soil water and salt limit and regulate the growth and distribution of herbaceous plants, which have an important influence on the community diversity of Populus euphratica forests. These results are helpful for understanding the community structure and diversity pattern of Populus euphratica along the Heihe river at the local scale and provide a scientific reference for the management and restoration of plant resources in the desert riparian Populus euphratica forest.

We conducted an experiment to study the effects of different grazing intensities on the community plant composition and interspecific relationships in the Stipa breviflora desert steppe, providing a reasonable and scientific theoretical basis. In this study, we took enclosure (CK) as control and set different grazing treatments (light grazing (LG), moderate grazing (MG) and heavy grazing (HG)) to analyze the plant community, variance ration (VR) and inter-species association coefficient, and the results showed that, species number in the CK, LG, MG, and HG treatments were 39, 34, 32, and 25, respectively, indicating that plant species number decreased with the increase of grazing intensity. Besides, variance ration in CK and LG was less than 1, while it was more than 1 in MG and HG. Further, the whole plant community was negatively correlated in CK and LG, showing a competitive relationship, while the whole plant community was positively correlated in MG and HG, showing an affinity relationship. Importantly, there had a positive association between Stipa breviflora and Cleistogenes songorica and between Artemisia frigida and Convolvulus ammannii in CK, but showed a negative correlation in MG. Likewise, there had a negative correlation between Cleistogenes songorica and Kochia prostrata in CK, but had a positive association in MG and HG. However, it had a positive association between Stipa breviflora and Kochia prostrata and between Cleistogenes songorica and Convolvulus ammannii in MG, indicating that moderate grazing could change the inter-species relationship from negative to positive association, and the opposite as the same. Finally, this study could provide important reference for the study of interspecific competition, community stability and ecological niche in the Stipa breviflora desert steppe.