Habitats In China Research Articles

Identification and characteristic analysis of semi-natural habitats in China's economically developed areas: New insights to inform cultivated land system ecological conservation

Identifying and characterizing semi-natural habitats (SNHs) are important to the ecological conservation of cultivated land systems and implementing China's ecological civilization strategy. This study revealed the concept and characteristics of SNHs in Chinese cultivated land systems regarding human activities, resource types, and spatial landscape patterns. The resource quantity, landscape quality, and spatial distribution of SNHs in Southern Jiangsu's cultivated land system were analyzed by constructing the identification model of “land use/land cover type-cultivated land use intensity-spatial landscape pattern”. The results showed that the area of SNHs in Southern Jiangsu's cultivated land system was 25.35%, significantly influenced by cultivated land intensification and expansion. The higher the cultivated land use intensity, the lower the quantity of SNHs, and the proportion of SNHs in the intensive-use pattern was only 2.97%. 68.18% of the SNHs in Southern Jiangsu were water, and habitats for important species, such as woodland, grassland, wetlands, and bare land, were scarce. A small patch area, high landscape fragmentation, poor landscape richness and diversity, and low connectivity accompanied increased cultivated land use intensity. From the extensive to intensive utilization, the spatial spread of SNHs from low-value aggregation to high-value scatter areas, with hotspot areas of cultivated land use intensity and SNHs existing only in a small part of Nanjing and Changzhou. This study provides a scientific reference for the rehabilitation and restoration of SNHs in the context of the ecological transformation of land use. It promotes the sustainable intensification of cultivated land systems. It also provides new ideas for linking ecological and urban spaces to form a stable and systematic national ecological safety network.

Exploring the chemical composition, medicinal benefits, and antioxidant activity of Plumula nelumbinis essential oil from different habitats in China

Plumula nelumbinis, a widely used traditional Chinese medicine known for its calming and nerve-soothing properties, contains essential oil as a primary component. However, research on P. nelumbinis essential oil (PNEO) is limited. This study aimed to investigate PNEO components, network target analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and antioxidant activity of P. nelumbinis from ten different habitats. GC–MS analysis identified 14 compounds in the essential oil, with CP12 (β-Sitosterol) having the highest concentration. Five compounds were identified for the first time in P. nelumbinis, with three of them reported for the first time in the Nelumbo. Network target analysis revealed 185 potential targets for 11 compounds and GO and KEGG enrichment analyses showed that PNEO was mainly located in the plasma membrane and could regulate a variety of molecular functions. KEGG pathway enrichment analysis revealed that the essential oil was primarily enriched in pathways related to cancer and the nervous system. PNEO demonstrated strong antioxidant activity, with N8 (Fujiannanping) showing the highest ABTS scavenging capacity and N7 (Hunanxiangtan) showing the highest DPPH radical scavenging capacity. Cell experiments showed that CP4, CP5 and CP10 had protective effects against H2O2-induced oxidative damage. The study suggests that P. nelumbinis from different regions may have slightly different pharmacological effects due to the presence of unique compounds, and further research is necessary to explore the potential therapeutic benefits of PNEO.

Spatial influence of exposure to green spaces on the climate comfort of urban habitats in China

This study aimed to improve the number of days with comfortable climate by increasing urban green space exposure. Geographic information technology and a spatial econometrics model were used to analyze the spatial influence and heterogeneity of urban green spaces on the climate comfort of urban habitats in China. The model was built using urban green space data extracted from remote sensing images, and days with comfortable climatic conditions, measured through the temperature and humidity index. The results showed that exposure to green space was generally high in Northeast and Southwest China, and low in Northwest and Southeast China. The exposure to green space of high urbanization level cities is generally lower than cities with low urbanization level. The climate comfort of urban habitats in the northeast and northwest is relatively cold, whereas that of those in the south, central and east is relatively hot. Southwest China has a complex and diverse range of climates. The climate of North China experiences greatly extremes of cold and heat in a year. The significance and mechanism of the influence of exposure to urban green space on climate comfort are differences in different regions. High exposure to green space can adjust thermal comfort by means of water storage, transpiration and heat absorption, reducing the range of temperature difference between day and night, and blocking cold and warm air flow. In addition, moderate human activities and sustainable land use can improve exposure to green space to help vegetation fully contact the air, affecting climate comfort by promoting evaporation and reducing thermal radiation.

Distribution pattern and change prediction of Phellodendron habitat in China under climate change.

Phellodendron has always been of great significance in promoting human health and ecological restoration. However, human activities and climate change have severely affected habitat, population dynamics and sustainable use of Phellodendron. Little is known about the geographical distribution pattern and their responses to climate change of Phellodendron. In order to reveal the impact of climate change on Phellodendron, we conducted a study based on natural distribution data of two species (297 occurrence points), 20 environmental factors, and an optimized MaxEnt model. Our results identified the main environmental factors influencing Phellodendron, predicted their potential geographical distribution, and assessed migration trends under climate change in China. Our analysis showed that Ph. amurense and Ph. chinense have potential suitable habitats of 62.89 × 104 and 70.71 × 104 km2, respectively. Temperature and precipitation were found to play an essential role in shaping the present geographical distribution of Phellodendron populations. Based on two future climate scenarios, we forecasted that the potential suitable habitat of Ph. amurense would decrease by 12.52% (SSP245) and increase by 25.28% (SSP585), while Ph. chinense would decline by 19.61% (SSP245) and 15.78% (SSP585) in the late-21st century. The potential suitable habitats of Ph. amurense and Ph. chinense would shift to northward and westward, respectively. Hydrothermal change was found to be the primary driver of the suitable habitat of Phellodendron populations in the future. We recommend establishing nature reserves for existing Phellodendron populations, especially Ph. chinense. Our study provided a practical framework for the impact of climate change on the suitable habitat of Phellodendron species and guided regional cultivation, long-term conservation, and sustainable use.

Taxonomy, phylogeny and evolution of freshwater Hypocreomycetidae (Sordariomycetes)

Hypocreomycetidae is a highly diverse group with species from various habitats. This subclass has been reported as pathogenic, endophytic, parasitic, saprobic, fungicolous, lichenicolous, algicolous, coprophilous and insect fungi from aquatic and terrestrial habitats. In this study, we focused on freshwater fungi of Hypocreomycetidae which resulted 41 fresh collections from China and Thailand. Based on morphological and phylogenetic analyses, we identified 26 species that belong to two orders (Hypocreales and Microascales) and six families (Bionectriaceae, Halosphaeriaceae, Microascaceae, Nectriaceae, Sarocladiaceae and Stachybotryaceae). Ten new species are introduced and 13 new habitats and geographic records are reported. Mariannaea superimposita, Stachybotrys chartarum and S. chlorohalonatus are recollected from freshwater habitats in China. Based on phylogenetic analysis of combined LSU, ITS, SSU, rpb2 and tef1-α sequences data, Emericellopsis is transferred to Hypocreales genera incertae sedis; Pseudoacremonium is transferred to Bionectriaceae; Sedecimiella is placed in Nectriaceae; Nautosphaeria and Tubakiella are excluded from Halosphaeriaceae and placed in Microascales genera incertae sedis; and Faurelina is excluded from Hypocreomycetidae. Varicosporella is placed under Atractium as a synonym of Atractium. In addition, phylogenetic analysis and divergence time estimates showed that Ascocodina, Campylospora, Cornuvesica and Xenodactylariaceae form distinct lineages in Hypocreomycetidae and they evolved in the family/order time frame. Hence, a new order (Xenodactylariales) and three new families (Ascocodinaceae, Campylosporaceae and Cornuvesicaceae) are introduced based on phylogenetic analysis, divergence time estimations and morphological characters. Ancestral character state analysis is performed for different habitats of Hypocreomycetidae including freshwater, marine and terrestrial taxa. The result indicates that marine and freshwater fungi evolved independently from terrestrial ancestors. The results further support those early diverging clades of this subclass, mostly comprising terrestrial taxa and freshwater and marine taxa have been secondarily derived, while the crown clade (Nectriaceae) is represented in all three habitats. The evolution of various morphological adaptations towards their habitual changes are also discussed.

Characteristics of plastid genomes in the genus Ceratostigma inhabiting arid habitats in China and their phylogenomic implications

BackgroundCeratostigma, a genus in the Plumbaginaceae, is an ecologically dominant group of shrubs, subshrub and herb mainly distributed in Qinghai-Tibet Plateau and North China. Ceratostigma has been the focal group in several studies, owing to their importance in economic and ecological value and unique breeding styles. Despite this, the genome information is limited and interspecific relationships within the genus Cerotastigma remains unexplored. Here we sequenced, assembled and characterized the 14 plastomes of five species, and conducted phylogenetic analyses of Cerotastigma using plastomes and nuclear ribosomal DNA (nrDNA) data.ResultsFourteen Cerotastigma plastomes possess typical quadripartite structures with lengths from 164,076 to 168,355 bp that consist of a large single copy, a small single copy and a pair of inverted repeats, and contain 127–128 genes, including 82–83 protein coding genes, 37 transfer RNAs and eight ribosomal RNAs. All plastomes are highly conservative and similar in gene order, simple sequence repeats (SSRs), long repeat repeats and codon usage patterns, but some structural variations in the border of single copy and inverted repeats. Mutation hotspots in coding (Pi values > 0.01: matK, ycf3, rps11, rps3, rpl22 and ndhF) and non-coding regions (Pi values > 0.02: trnH-psbA, rps16-trnQ, ndhF-rpl32 and rpl32-trnL) were identified among plastid genomes that could be served as potential molecular markers for species delimitation and genetic variation studies in Cerotastigma. Gene selective pressure analysis showed that most protein-coding genes have been under purifying selection except two genes. Phylogenetic analyses based on whole plastomes and nrDNA strongly support that the five species formed a monophyletic clade. Moreover, interspecific delimitation was well resolved except C. minus, individuals of which clustered into two main clades corresponding to their geographic distributions. The topology inferred from the nrDNA dataset was not congruent with the tree derived from the analyses of the plastid dataset.ConclusionThese findings represent the first important step in elucidating plastome evolution in this widespread distribution genus Cerotastigma in the Qinghai-Tibet Plateau. The detailed information could provide a valuable resource for understanding the molecular dynamics and phylogenetic relationship in the family Plumbaginaceae. Lineage genetic divergence within C. minus was perhaps promoted by geographic barriers in the Himalaya and Hengduan Mountains region, but introgression or hybridization could not be completely excluded.

Changes in the landscape patterns of Black-necked Crane habitat and its correlation with their individual population numbers during the past 40 years in China.

The landscape pattern of the Black-necked Crane (Grus nigricollis) habitat in China changed at different spatial scales and long-term periods due to natural factors and human activities, and habitat reduction and fragmentation threatened the survival of Black-necked Cranes. The factors driving the habitat landscape pattern and individual population changes of Black-necked Cranes remain to be studied. In this paper, based on remote sensing data of land use from 1980 to 2020, the changes in landscape pattern and fragmentation of the Black-necked Crane habitat in China over 40 years were analyzed from two different spatial scales using the land cover transfer matrix and landscape index. The correlation between landscape and Black-necked Crane individual population was analyzed. The most obvious observations were as follows: (1) Although transformation between landscapes occurred to varying degrees, the area of wetlands and arable land in the breeding and the wintering areas (net) increased significantly from 1980 to 2020. (2) Habitat fragmentation existed in the breeding and the wintering area and was more obvious in the wintering area. (3) The number of individuals of Black-necked Cranes increased period by period, and habitat fragmentation did not inhibit their population growth. (4) The number of individuals of Black-necked Crane was closely related to the wetland and arable land. The increasing area of wetlands and arable and the increasing landscape shape complexity all contributed to the growth of the individual population. The results also suggested that the number of individuals of Black-necked Crane was not threatened by the expanding arable land in China, and they might benefit from arable landscapes. The conservation of Black-necked Cranes should focus on the relationship between individual Black-necked Cranes and arable landscapes, and the conservation of other waterbirds should also focus on the relationship between individual waterbirds and other landscapes.

Authentication, chemical profiles analysis, and quality evaluation of corn silk via DNA barcoding and UPLC-LTQ/Orbitrap MS chemical profiling

Corn silk is commonly consumed in teas, food ingredients, and herbal medicines. Several varieties of corn silk are grown in different habitats in China. However, as information regarding their phytochemistry and genetic diversity is limited, their medicinal potential has not been utilized thoroughly. Thus, we aimed to use a combination of DNA barcoding based on specific primer ITSC sequences and ultra-performance liquid chromatography coupled with linear trap quadrupole-Orbitrap mass spectrometry (UPLC-LTQ/Orbitrap MS) approach for identifying and evaluating corn silk. ITSC barcoding helped us to identify that 52 samples could be classified into 7 groups of corn silk varieties, but the widely used nrITS and psbA-trnH barcodes failed to identify these varieties. UPLC-LTQ/Orbitrap MS was used to study the components in alcohol extracts derived from different corn silk varieties, and the detected chemical components were analyzed via bioinformatics techniques. We proposed 199 components using untargeted UPLC-LTQ/Orbitrap MS-based metabolomics analysis and identified 67 components. PCA and OPLS-DA analysis revealed two distinct chemotypes by selecting 27 components that could act as difference indicators. KEGG analysis showed that the 199 components were enriched in 12 metabolic pathways. The results showed that corn silk is rich in many types of chemicals and DNA barcoding is better than UPLC-LTQ/Orbitrap MS in distinguishing the differences between different varieties of corn silk. Our findings provide new insights into the chemical and molecular characteristics of different varieties of corn silk, which play a crucial role in the utilization of corn silk resources.

Coordinated development of rural habitat in China: A study of measurement, spatio-temporal evolution and convergence

Rural revitalization is inseparable from the construction of human habitat, the coordinated development of rural culture and physical environment profoundly affects the quality of the habitat environment, and the improvement of the habitat environment requires a “soft and hard balance”. Previous studies have focused more on the overall quality of rural habitat and neglected the coordination of habitat construction. The contribution of our study is the construction of an evaluation index system for the China Rural Habitat Coordinated Degree (CRHCD). The main research results show that the level of soft and hard environment of China's rural habitat is growing, but the construction of soft environment is a shortcoming. CRHCD leaps from nearly dysfunctional (0.440) to barely coordinated (0.538), and is in a transitional stage with stable spatial structure, showing the trend of “from point to line, from line to surface”, and gradually developing from coastal to inland. Spatial convergence analysis shows that CRHCD converges fastest in the eastern region, while the northeastern region shows dispersion characteristics. Our results provide a theoretical basis and policy recommendations for the systematic coordination and regional balanced development of rural habitat in China.

Sound environment in an urban apartment building during and after the COVID-19 lockdown.

Quiet areas, such as quiet communities, are encouraged to maintain a harmonious and peaceful urban living environment, and the design approach has drawn increasing attention in recent years. Related residential standards define the thresholds of quietness concerning noise pollution problems. However, the variations in height across floors of high-rise buildings and time in sound environments have not been detailed. The city of Shanghai experienced a citywide lockdown to contain the spread of COVID-19 showing the evidence of quietness with marked reductions in anthropogenic noise. Here, we conducted noise monitoring in a 14-story apartment building surrounded and shielded by other buildings in a typical urban community during and after lockdown. The mean value of the equivalent continuous A-weighted sound pressure level (L Aeq ) of all 14 floors after lockdown was higher than that during lockdown, and the differences were 3.6 and 3.1 dB during the daytime and night-time periods, respectively. The L Aeq values at low heights were slightly lower than those at high heights during and after lockdown. The variations due to the different heights were not great. However, the change tendency from the ground to the top floors was similar and correlated during and after lockdown. The difference between the maximum and minimum values of the floors was 3 dB during the daytime period and 4.5 to 5.1 dB during the night-time period. The day equivalent continuous A-weighted sound pressure level (L day ) and night equivalent continuous A-weighted sound pressure level (L night ) at the middle building height increased 4.0 and 1.3 dB, respectively, after lockdown. The L Aeq change tendency during a daily cycle during and after lockdown was similar and highly correlated. The differences in the frequency characteristics of noise level were larger within the 63 to 2,000 Hz range. We suggest that the building represents a typical quiet living condition in high-density habitats in China. Notably, the difference is approximately 3 to 4 dB, and the patterns of variation in height and time are similar between the absence and limited presence of anthropogenic noise. In practice, it would be useful to consider specific floor level or time of day.

Proteomic characterization and comparison of milk fat globule membrane proteins of Saanen goat milk from 3 habitats in China using SWATH-MS technique

Saanen goats are among the major dairy goats in China. In present study, variation of milk fat globule membrane proteins profile of Saanen goat milk caused by geographic location was investigated using sequential window acquisition of all theoretical fragment ions data-independent acquisition mass spectrometry based proteomic approach. A total of 1,001 proteins were quantified in goat milk collected from 3 habitats of China [Guangdong (GD); Inner Mongolia (IM); Shannxi (SX)]. Most of the proteins were found to act cellular process of biological process, cell of cellular component, binding of molecular function after Gene Ontology annotation and metabolic of pathway indicated by Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Differentially expressed proteins (DEP) for GD versus IM, GD versus SX, IM versus SX were identified to be 81, 91, and 44, respectively. Gene Ontology enrichment analysis showed that the greatest DEP for 3 groups (GD vs. IM, GD vs. SX, IM vs. SX) were cellular process, cellular process and organonitrogen compound biosynthetic process/immune system process for biological process. For cellular component, the largest number of DEP for 3 comparison groups were organelle, organelle and organelle/intracellular. For molecular function, DEP of the 3 comparison groups were expressed most in structural molecule activity, binding and anion binding, respectively. Pathways with the majority of DEP were ribosome, systemic lupus erythematosus and primary immunodeficiency/systemic lupus erythematosus/amoebiasis/PI3K-Akt signaling pathway for GD versus IM, GD versus SX and IM versus SX, severally. Protein-protein interaction network analysis showed that DEP interacted most were 40S ribosomal protein S5, fibronectin and Cytochrome b-c1 complex subunit 2, mitochondrial for GD versus IM, GD versus SX and IM versus SX, separately. Data may give useful information for goat milk selection and milk authenticity in China.

The correlation between pharmacological activity and contents of eight constituents of Glycyrrhiza uralensis Fisch

Licorice (Glycyrrhiza uralensis Fisch. (GUF), Leguminosae) has been extensively applied in traditional Chinese medicine (TCM) to treat diseases, exactly, in almost half of Chinese herbal prescription. However, the relationship between chemical contents and efficacy has not been established, which could evaluate GUF quality. To create a simple and effective quality-evaluation method, 33 batches of GUF from different habitats in China were collected. The correlation between eight constituents (liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, licochalcone A, glabridin and glycyrrhetinic acid) and pharmacological activities (anti-inflammatory, antioxidant and immunoregulatory) was analyzed per the partial least squares regression method. Results showed that eight constituents correlated significantly with the pharmacological activity. The correlation equation modes between pharmacological activity and contents of eight constituents were constructed and verified to be reliable. In GUF extract, the main constituents liquiritin, isoliquiritin and glycyrrhizic acid exhibited positive influence on anti-inflammatory and antioxidant effect with different potent, while the metabolites liquiritigenin and isoliquiritigenin exhibited positive effect on the immunoregulatory activity and glycyrrhetinic acid exhibited positive effect on all the tested activities. Thus, our chemical-efficacy correlation method is reliable and feasible to predict the pharmacological activity based on its eight constituents. It could be powerful in quality control of GUF and provides a useful way for quality evaluation of other medicinal herbs.

Invasive Spartina alterniflora habitat forms high energy fluxes but low food web stability compared to adjacent native vegetated habitats

Invasive Spartina spp. mostly colonizes a bare tidal flat and then establishes a new vegetated habitat, where it promotes the productivity of local ecosystems. However, it was unclear whether the invasive habitat could well exhibit ecosystem functioning, e.g. how its high productivity propagates throughout the food web and whether it thereby develops a high food web stability relative to native vegetated habitats. By developing quantitative food webs for a long-established invasive Spartina alterniflora habitat and adjacent native salt marsh (Suaeda salsa) and seagrass (Zostera japonica) habitats in China's Yellow River Delta, we investigated the distributions of energy fluxes, assessed the stability of food webs, and investigated the net trophic effects between trophic groups by combining all direct and indirect trophic interactions. Results showed that the total energy flux in the invasive S. alterniflora habitat was comparable to that in the Z. japonica habitat, whereas 4.5 times higher than that in the S. salsa habitat. While, the invasive habitat had the lowest trophic transfer efficiencies. Food web stability in the invasive habitat was about 3 and 40 times lower than that in the S. salsa and Z. japonica habitats, respectively. Additionally, there were strong net effects caused by intermediate invertebrate species in the invasive habitat rather than by fish species in both native habitats. This study revealed the contradiction between the promotion of energy fluxes and the decrease of food web stability resulting from the invasion of S. alterniflora, which provides new insights into the community-based management of plant invasions.

Insights into taxonomy and phylogenetic relationships of eleven Aristolochia species based on chloroplast genome.

The Aristolochia, as an important genus comprised of over 400 species, has attracted much interest because of its unique chemical and pharmacological properties. However, the intrageneric taxonomy and species identification within Aristolochia have long been difficult because of the complexity of their morphological variations and lack of high-resolution molecular markers. In this study, we sampled 11 species of Aristolochia collected from distinct habitats in China, and sequenced their complete chloroplast (cp) genomes. The 11 cp genomes of Aristolochia ranged in size from 159,375bp (A. tagala) to 160,626 bp (A. tubiflora), each containing a large single-copy (LSC) region (88,914-90,251 bp), a small single-copy (SSC) region (19,311-19,917 bp), and a pair of inverted repeats (IR) (25,175-25,698 bp). These cp genomes contained 130-131 genes each, including 85 protein-coding genes (CDS), 8 ribosomal RNA genes, and 37-38 transfer RNA genes. In addition, the four types of repeats (forward, palindromic, reverse, and complement repeats) were examined in Aristolochia species. A. littoralis had the highest number of repeats (168), while A. tagala had the lowest number (42). The total number of simple sequence repeats (SSRs) is at least 99 in A. kwangsiensis, and, at most, 161 in A. gigantea. Interestingly, we detected eleven highly mutational hotspot regions, including six gene regions (clpP, matK, ndhF, psbT, rps16, trnK-UUU) and five intergenic spacer regions (ccsA-ndhD, psbZ-trnG-GCC, rpl33-rps18, rps16-trnQ-UUG, trnS-GCU-trnG-UCC). The phylogenetic analysis based on the 72 protein-coding genes showed that 11 Aristolochia species were divided into two clades which strongly supported the generic segregates of the subgenus Aristolochia and Siphisia. This research will provide the basis for the classification, identification, and phylogeny of medicinal plants of Aristolochiaceae.

Fungal diversities and community assembly processes show different biogeographical patterns in forest and grassland soil ecosystems.

Soil fungal community has been largely explored by comparing their natural diversity. However, there is a relatively small body of literature concerned with fungal community assembly processes and their co-occurrence network correlations carried out across large spatial-temporal scales with complex environmental gradients in natural ecosystems and different habitats in China. Thus, soil fungal community assembly processes were assessed to predict changes in soil function in 98 different forest and grassland sites from the Sichuan, Hubei, and Hebei Provinces of China using high-throughput sequencing of nuclear ribosomal internal transcribed spacer 2 (ITS-2). The 10 most abundant fungal phyla results showed that Ascomycota was the most abundant phylum in forests from Sichuan province (64.42%) and grassland habitats from Hebei province (53.46%). Moreover, core fungal taxa (487 OTUs) represented 0.35% of total fungal OTUs. We observed higher fungal Shannon diversity and richness (the Chao1 index) from diverse mixed forests of the Sichuan and Hubei Provinces than the mono-cultured forest and grassland habitats in Hebei Province. Although fungal alpha and beta diversities exhibited different biogeographical patterns, the fungal assembly pattern was mostly driven by dispersal limitation than selection in different habitats. Fungal co-occurrence analyses showed that the network was more intense at Saihanba National Forest Park (SNFP, Hebei). In contrast, the co-occurrence network was more complex at boundaries between forests and grasslands at SNFP. Additionally, the highest number of positive (co-presence or co-operative) correlations of fungal genera were inferred from grassland habitat, which led fungal communities to form commensalism relationships compared to forest areas with having higher negative correlations (mutual exclusion or competitive). The generalized additive model (GAM) analysis showed that the association of fungal Shannon diversity and richness indices with geographical coordinates did not follow a general pattern; instead, the fluctuation of these indices was restricted to local geographical coordinates at each sampling location. These results indicated the existence of a site effect on the diversity of fungal communities across our sampling sites. Our observation suggested that higher fungal diversity and richness of fungal taxa in a particular habitat are not necessarily associated with more complex networks.

Content analysis and quality evaluation of main active components and mineral elements of Cynomorium songaricum in different habitats

To clarify the content characteristics of the main active components and mineral elements of Cynomorium songaricum under different habitat conditions, and further explore the relationship between the quality of C. songaricum and habitats, this study took C. songaricum from 25 different habitats in China as the research object, and measured the contents of 8 main active components and 12 mineral elements separately. Diversity analysis, correlation analysis, principal component analysis and cluster analysis were carried out. The results showed that the genetic diversity of total flavonoids, ursolic acid, ether extract, potassium(K), phosphorus(P) and zinc(Zn) in C. songaricum was high. The coefficient of variation of crude polysaccharide, ether extract, gallic acid, protocatechuic aldehyde, catechin, epicatechin, calcium(Ca), sodium(Na), magnesium(Mg), sulfur(S), iron(Fe), manganese(Mn), selenium(Se) and nickel(Ni) were all over 36%, indicating that the quality of C. songaricum was significantly affected by habitats. There were strong synergistic and weak antagonistic effects among the contents of the 8 active components, and complex antagonistic and synergistic effects among the contents of the 12 mineral elements. Principal component analysis revealed that crude polysaccharide, ursolic acid, catechin, epicatechin and total flavonoids could be used as the characteristic components to evaluate the quality of C. songaricum, and Na, copper(Cu), Mn and Ni were the characteristic elements to evaluate the quality of C. songaricum. In cluster ana-lysis, the second group with the main active components as cluster center had better quality in terms of the content of active substances, and the second group with the mineral elements as cluster center had higher utilization potential in the exploitation of mineral elements. This study could provide a basis for resource evaluation and breeding of excellent varieties of C. songaricum in different habitats, and provide a reference for cultivation and identification of C. songaricum.

Modeling habitat suitability of Hippophae rhamnoides L. using MaxEnt under climate change in China: A case study of H. r. sinensis and H. r. turkestanica

Hippophae rhamnoides is widely known for its important ecological, economic, and social benefits. It is known as the pioneer plant of soil and water conservation, with homology in food and medicine. With the climate warming in recent years, the numbers of this species and countries with this plant have decreased steadily. H. r. sinensis and H. r. turkestanica have the widest distribution area in China, which account for more than 90% of the total national Hippophae rhamnoides resources. We firstly screened the presence data and downscale the environment variables (climate and soil) by correlation analysis. Secondly, based on the 232 occurrence data of H. r. sinensis and 10 environmental variables, the 73 occurrence data of H. r. turkestanica and 11 environmental variables, we simulated and predicted their suitable habitats in China, both at the current time and in the 2050S (2041–2060), and analyzed the dominant factors effecting its distribution by using MaxEnt. Finally, we studied the habitat variations and centroid migrations of these subspecies under future climate scenarios using the spatial analysis function of ArcGIS. The results indicated that the area of suitable habitat for H. r. sinensis is much larger than that of H. r. trkestanica in China. The suitable habitat of H. r. sinensis is concentrated in the middle and upper reaches of the Yellow River, mainly distributed in Shaanxi, Shanxi, Sichuan, Qinghai, Gansu, Ningxia, Tibet, and Inner Mongolia, and that of H. r. trkestanica is mainly distributed in Xinjiang and Tibet. The former is mainly affected by bio13 (precipitation of the wettest month), bio11 (mean temperature of the coldest quarte) and bio3 (Isothermality), and the latter is mainly affected by bio13 (precipitation of the wettest month), bio2 (mean diurnal range) and bio15 (precipitation seasonality), and the former is also more stable in the face of future climate change. They are more susceptible to climate than soil in their survival. Although, the two subspecies tend to expand and migrate toward lower latitude under future climate scenarios, there are some differences. H. r. sinensis will migrate westward, while H. r. trkestanica will migrate eastward as a whole. They have a high stability of suitable habitat and are not at risk of extinction in the future. The study’s findings help to clarify the resource reserve of Hippophae rhamnoides L. in China, which will help to guide the protection of wild resources and to popularize artificial planting in suitable areas, and provides scientific basis for the protection of ecological environment.

Potential Global Distribution of the Habitat of Endangered Gentiana rhodantha Franch: Predictions Based on MaxEnt Ecological Niche Modeling

Continued global climate and environmental changes have led to habitat narrowing or migration of medicinal plants. Gentiana rhodantha Franch. ex Hemsl. is a medicinal plant for ethnic minorities in China, and it has a remarkable curative effect in the treatment of lung-heat cough. However, its habitat is gradually decreasing, and the species has been listed as an endangered ethnic medicine due to excessive harvesting. Here, based on CMIP6 bioclimatic data and 117 species occurrence records, the maximum entropy model (MaxEnt), combined with ArcGIS technology, was applied to predict the potentially suitable habitats for G. rhodantha under different climate scenarios. The results showed that the most critical bioclimatic variables affecting G. rhodantha are the precipitation of the warmest quarter (Bio18) and the mean temperature of the coldest quarter (Bio11). The highly suitable habitats of G. rhodantha are mainly concentrated in Belt and Road (“B&R”) countries, including China, Bhutan, and Vietnam. However, under different climate change scenarios, the fragmentation extent of suitable habitats in China will generally increase, the suitable area will show a decreasing trend as a whole, the distribution center will shift to the northeast, and the distance will increase with time. Notably, the shrinkage of the high suitability area was the most obvious for the 2081–2100 SSP585 scenario, with a total of 358,385.2 km2. These findings contribute to the understanding of the geo-ecological characteristics of this species, and provide guidelines for the conservation, management, monitoring, and cultivation of G. rhodantha.

Is the Lesser Khingan Suitable for the Amur Tiger Restoration? Perspectives with the Current State of the Habitat and Prey Base

The Amur tiger (Panthera tigris) has a status of being endangered on the world's IUCN red list. The northwestern part of its range is situated in Russia and China, where tigers were exterminated by humans in the 1950-1970s. To restore tiger population within a historical range, an estimation of the habitat suitability is firstly needed. The Lesser Khingan mountains (Heilongjiang) was analyzed. Habitat types were mapped by satellite images analysis and field proven. The potential habitats of the main tiger's prey species (wild boar (Sus scrofa), roe deer (Capreolus pygargus), and red deer (Cervus elaphus xanthopygus) were also assessed. Maximum entropy and linear discriminant analysis methods were applied and compared for species distribution modeling (SDM). Species distribution maps were used to design an ecological network. The fragmentation of habitat patches was evaluated by spatial ecological metrics. The habitat patches with the best metrics were assigned as cores for the ecological network, which were connected by calculated corridors. The least cost distance method (based on distance to roads and settlements) was used. The recovery of the Amur tiger in habitats of China's Lesser Khingan is shown to be possible. Types of habitats were calculated as natural corridors for moving tigers. They are mainly located at the forests' edges and characterized with various canopy structures and high variability in the tree species composition. Three potential transboundary corridors are described: (a) foothills and low mountains of the northern Lesser Khingan; (b) connection between the southeast Lesser Khingan and the western part of the Wandashan mountain system; and (c) corridor within foothills and low mountains of the eastern part of Lesser Khingan. It is recommended to establish protected areas for the important tiger core habitats, and the main optimal ways for their migrations are described during the current investigation. Moreover, it is necessary to implement habitat recovery activities for key areas.

Diverse Response Pattern to Anoxia in Three Freshwater Turtle Species.

With increasing water eutrophication and global warming, anoxia and hypoxia are becoming more and more common in water environments. Most vertebrates have a limited tolerance to anoxia of only a few minutes, but some species, such as turtles, can survive for months being exposed to anoxia. Antioxidant defense systems may have a potential role in resisting anoxia stress in freshwater turtles. The three-keeled pond turtle Chinemys reevesii, the snapping turtle Chelydra serpentina and the soft-shelled turtle Pelodiscus sinensis are three popular aquaculture species and share similar habitats in China. While C. reevesii and C. serpentina are hard-shelled turtles with poor skin permeability, P. sinensis is soft-shelled turtle whose skin permeability is good. We examined the antioxidant defense responses in different tissues of the three turtle species under acute anoxia stress for 10 h and subsequently recovered for 24 h in order to reveal the response patterns of the antioxidant defense system of the three turtle species that differed in morphological structure and life history strategy. We found that the antioxidant response patterns to acute anoxia stress were tissue- and species-specific. The soft-shelled turtle was more sensitive to anoxia than the hard-shelled turtles. Under anoxia stress, the three species kept the activities of most antioxidant enzymes stable. C. reevesii and P. sinensis were highly dependent on vitamin C in antioxidant defense, while high activities of structural antioxidant enzymes were found in the tissues of C. serpentina. The above diverse patterns may be related with adaptive evolution of morphological structure and physiological functions of the three turtle species.