Table of Content

10 January 2024, Volume 43 Issue 1

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Soil moisture affected plant community characteristics and ecosystem multifunctionality of alpine grasslands on the eastern Qinghai-Tibet Plateau.

MA Jianguo, ZHU Huaide, LI Yuman, YANG Xiaoqian, YAO Mengfan, YANG Zhenghui, WANG Xiaobo

2024, 43(1):  1-7.  doi:10.13292/j.1000-4890.202401.034

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Environment changes have a profound influence on biological diversity and ecosystem function of alpine grasslands on Qinghai-Tibet Plateau, by altering the spatial patterns of plant communities. Plant communities generally change over space with changing environment conditions. However, our understanding about what factors drive such a variation remains controversial. Here, we investigated the importance of different soil factors to plant community characteristics from west to east on the eastern Qinghai-Tibet Plateau and the sensitivity of plant communities to these factors, as well as the effects of key soil factors on ecosystem multifunctionality. The results showed that there are differences in the importance and sensitivity of soil factors to plant communities. Compared with other soil factors, soil moisture was more important in affecting all the measured plant community indices (P<0.05). Plant community indices showed a strong sensitivity to soil moisture (P<0.05). There was a significant nonlinear positive relationship between soil moisture and ecosystem multifunctionality (P<0.05). Our results indicate that soil moisture may play a pivotal role in governing spatial variation of plant communities and consequently has a large effect on grassland ecosystem functions on Qinghai-Tibet Plateau.





Responses of anatomical structures of different root orders of Kobresia humilis to habitat aridification in an alpine meadow.

HAN Yuzhen, CHEN Fenglin, YANG Chunjiao, ZHANG Dacai

2024, 43(1):  8-16.  doi:10.13292/j.1000-4890.202401.028

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Roots consist of different orders. However, it is unclear whether their anatomical structures are consistent with their response to aridification of habitat. In this study, roots of Kobresia humilis were collected from six plots along a gradient of habitat aridification in an alpine meadow of the Dongda Mountains, southeast Tibet. The paraffin method, one-way ANOVA and principal component analysis were used to examine the difference of anatomical structures and the strength of plasticity for the first and second-order roots from habitats with different moistures. There was no difference of anatomical structures between the first and second-order roots. The epidermal cells were nearly rectangular and closely arranged, and area of single cell was large (87.6-126.0 μm²). The anatomical structures of the first and second-order roots were not consistent in response to habitat aridification. Area and thickness of the epidermal cell and cortex thickness (including thick-walled tissues and parenchyma) in the first-order roots had significant negative correlation with soil moisture, while those in the second-order roots had significant positive correlation (P<0.05). The ratios of epidermis to diameter of first-order roots were significantly different along the soil moisture gradient, while other anatomical structures had no significant difference. The ratios of anatomical structures (except cortical thick-walled tissues) of second-order roots were significantly different along soil moisture gradient. In the first-order roots, the thickness of cortical parenchyma had strongest plasticity, while the thickness of cortical thick-walled tissue had weakest plasticity; for the second-order roots, the strongest was transverse section area and the weakest was vascular cylinder area. Collectively, the anatomical structure of root epidermis and cortex had strong plasticity to the changes of soil moisture. However, anatomical structure of different root orders had different response mechanisms to aridification, showing an improved potential capability to store or absorb water. Therefore, root order method provides a new idea for understanding the adaptation of roots to changing habitats.





Effects of temperature on the relationship between plant seed germination and pathogenic fungal infection in alpine grasslands on the Qinghai-Tibet Plateau. 

TIAN Zhen, ZHANG Shuqin, LI Wenjie, JIANG Feifei, CHEN Tao

2024, 43(1):  17-24. 

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Under natural conditions, pathogenic fungal infection is an important factor leading to seed mortality. However, the relationship between seed characteristics (e.g., dormancy and germination rate) and pathogenic fungal infection under climate change is poorly understood. In this study, seeds of 17 herbaceous plant species collected from an alpine meadow of the Qinghai-Tibet Plateau were used to perform a germination trail at different temperatures (10, 15, 20, and 25 ℃). We examined the effect of temperature on seed germination characteristics and fungal infection, and explored the relationship between fungal infection and seed death and seed germination rate and dormancy characteristics under different temperature conditions. There was a significant negative correlation between seed fungal infection rate and seed mortality and seed dormancy under each temperature (P<0.001), with the strongest correlation at 25 ℃. Only at 25 ℃, the fungal infection rate and mortality of seeds were significantly positively correlated with the average germination time of seeds (P<0.05). These results showed that seed dormancy can effectively resist the infection of pathogenic fungi under different temperature conditions. In addition, seeds can effectively escape the infection of pathogenic fungi through rapid germination, but their relationship with pathogenic fungi is greatly affected by temperature. This study provides a scientific basis for understanding the relationship between seed characteristics and pathogenic fungi in the context of climate change.





Effect of warming on nitrogen and phosphorus resorption of Carex muliensis in an alpine marsh on Zoigê Plateau.

CHEN Tiansong, HU Zhaoyi, SHEN Jinyang, ZHAO Li, LIU Hongqiang, XIONG Yinhong, SUN Rongqing, DONG Liqin, ZHANG Kun

2024, 43(1):  25-32.  doi:10.13292/j.1000-4890.202401.033

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Nutrient resorption is an important nutrient conservation mechanism of plants and an important component of nutrient cycling. Temperature change can affect nutrient resorption of plants. To explore the responses of nutrient resorption of Carex muliensis in an alpine marsh on Zoigê Plateau to climate warming, we measured nitrogen (N) and phosphorus (P) contents of mature and senescent leaves of C. muliensis in a field simulated warming experiment, and analyzed the difference of resorption efficiency. The results showed that the average contents of leaf N and P of C. muliensis were 11.44 and 1.19 mg·g^-1 respectively, and the average N resorption efficiency (NRE) and P resorption efficiency (PRE) were 61.8% and 69.0% respectively. Warming significantly decreased N content in mature leaves and increased P content in senescent leaves (P<0.01), but did not affect P content in mature leaves and N content in senescent leaves. Warming led to a significant decrease in N:P in mature and senescent leaves (P<0.01), NRE (P<0.05), and PRE (P<0.01). NRE and PRE of C. muliensis were significantly positively correlated with the N and P contents of mature leaves, and negatively correlated with the N and P contents of senescent leaves. Moreover, the growth of C. muliensis was limited by P, and the increase in temperature might lead to the change of nutrient limitation, indicating that the nutrient resorption of C. muliensis may also be regulated by stoichiometry. These results are helpful to understand and predict the responses of nutrient cycling in the Zoigê Plateau to future climate changes, and provide data support and experimental evidence for the prediction of NRE change of alpine marshes under climate warming.





Effects of iron addition on photodegradation of soil organic carbon under different slope aspects in a subalpine meadow.

GUO Xiaoyu, CHENG Man, XU Maohong, HE Xinhua, WEN Yongli

2024, 43(1):  33-40.  doi:10.13292/j.1000-4890.202401.030

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Increasing soil organic carbon (SOC) mineralization rate is an important ecological process that most terrestrial ecosystems are undergoing under the context of global UVB enhancement. Iron (Fe) oxides could affect the stability of SOC through adsorption or coprecipitation with carbon, and play an important role in regulating the process of soil carbon cycling. With an incubation experiment, we examined the effects of Fe addition on the photodegradation of SOC in surface soils (0-5 cm depth) from the southeast and northwest slopes of Shunwangping subalpine meadow in Lishan National Nature Reserve, Shanxi, northwest China. There were four treatments: (1) ambient light intensity under natural room light exposure (AM), (2) AM+0.1 g Fe(II) as FeCl₂/0.02 kg soil (AM+Fe), (3) minus 280-320 nm ultraviolet-B radiation with Mylar tape under no-Fe addition (-UVB), and (4) UVB + Fe addition (-UVB+Fe). The UVB radiation was 60 μW·cm^-2 at noon of 12:00 pm and no UVB radiation was detected under the -UVB treatment. Fresh soil was incubated at 25±1 oC under 50% field water-holding capacity for 1, 3, 5, 10, 15, 20, 30, and 50 days. CO₂ released from incubated soil was absorbed with 0.1 mol·L^-1 NaOH and then analyzed firstly with 1 mol·L^-1 BaCl₂ and then 0.05 mol·L^-1 HCl. Results showed that the cumulative mineralization and mineralization rate of SOC were significantly greater in the northwest slope than that in the southeast slope, mainly because the lower concentration of amorphous iron (Feo-p) in soil from the northwest slope led to a weaker SOC protection. Moreover, photodegradation of SOC occurred under UVB radiation, which promoted the mineralization of soil organic carbon. The increasing extent of mineralization amount and mineralization rate under UVB radiation, namely photo-priming, was significantly higher in the northwest slope than that in the southeast slope. The addition of exogenous Fe resulted in a significant decrease of both cumulative mineralization and mineralization efficiency of SOC, as well as a significant decrease of SOC photodegradation in both slopes. Our results demonstrated that SOC in the northwest slope has strong photodegradation potential with the continuous enhancement of UVB radiation in the future, and that exogenous Fe addition could alleviate the photodegradation of surface SOC. This study can provide theoretical basis for understanding of SOC sequestration mechanism in subalpine meadows under the background of climate change.





Responses of soil respiration and its components to nitrogen addition in an alpine meadow.

SHI Jiawei, LIAO Jiaqiang, WEI Chunxue, PENG Yifei, LI Tingting, HU Jian, WANG Jinsong, ZHOU Qingping

2024, 43(1):  41-49.  doi:10.13292/j.1000-4890.202401.035

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This study aimed to compare the changes of soil respiration rate (Rs), autotrophic respiration rate (Ra), and heterotrophic respiration rate (Rh) across a nitrogen application gradient in an alpine meadow on the Qinghai-Tibet Plateau, reveal the main influencing factors of soil respiration and its components, and provide a scientific basis for evaluating soil carbon release from alpine meadows under future nitrogen deposition. In 2014, a nitrogen addition platform was established in the alpine meadow of the Qinghai-Tibet Plateau in Hongyuan, Sichuan, following a completely randomized block experimental design with six levels of nitrogen addition, including 0 (N0, control), 2 (N2), 4 (N4), 8 (N8), 16 (N16) and 32 (N32) g N·m^-2·a^-1. Nitrogen application significantly decreased soil respiration and its components (P<0.05), and Ra decreased more than Rh, resulting in a gradual increase of Rh/Rs with the nitrogen addition gradient. There were significant exponential positive correlations between Ra and Rh and soil temperature under different nitrogen addition treatments (P<0.05). Nitrogen addition decreased the temperature sensitivity (Q₁₀) of Ra, but increased that of Rh. The relationship between the components of soil respiration and soil moisture was not significant, but the two-factor model of soil temperature and soil moisture explained Ra and Rh better than the single-factor model. Our results enhance mechanistic understanding of soil respiration and its components in response to nitrogen addition in an alpine meadow, and provide a theoretical basis for evaluating the response of alpine meadow ecosystems to atmospheric nitrogen deposition and guiding ecosystem management.





Impacts of artificial grasslands on soil organic carbon fractions in a degraded alpine meadow of the Three-River Source Region.

LI Xiaoyan, LI Yonghui, QIN Wenping, SUN Yu, MA Zhiwen, LIU Xiang

2024, 43(1):  50-56.  doi:10.13292/j.1000-4890.202401.036

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The degradation of alpine meadows in the Three-River Source Region has posed an enormous threat to regional ecological safety. Recovery of soil organic carbon pool is the key to restore degraded alpine meadows. In this study, a degraded alpine meadow (DAM), an artificial grassland established for 3 years (AG3) and an artificial grassland established for 7 years (AG7) in the Three-River Source Region were chosen to quantitatively evaluate the changes in fractions and biochemical stability of soil organic carbon after establishing artificial grasslands using acid hydrolysis approach, which divided soil organic carbon pool into labile carbon pool I, labile carbon pool II, and recalcitrant carbon pool. The results showed that the contents of soil organic carbon fractions decreased following the order: recalcitrant carbon pool > labile carbon pool I > labile carbon pool II at all study sites, suggesting that recalcitrant carbon pool was the main component of soil organic carbon pool. After establishing artificial grassland for 3 years, the contents of soil total organic carbon, labile carbon pool I, and recalcitrant carbon pool did not change, whereas the content of soil labile carbon pool II significantly decreased in the 0-30 cm soil layer (P<0.05). By contrast, establishing artificial grassland for 7 years generally increased the contents of soil total organic carbon and most fractions except for labile carbon pool II. The recalcitrant index of soil organic carbon varied in ranges of 43.7%-48.4%, 42.3%-48.9% and 42.3%-53.4% at DAM, AG3 and AG7, respectively. Although the recalcitrant index of soil organic carbon at AG7 was higher than that at the other two sites, the difference was only significant in the 10-20 cm soil layer (P<0.05). In conclusion, the findings indicate that long-term artificial vegetation restoration is an effective way to improve the content and biochemical stability of soil organic carbon in degraded alpine meadow of the Three-River Source Region, which would contribute to the recovery of carbon sink function of soil.





The effect of livestock assemblage on plant community and productivity in alpine grassland.

LIU Yuzhen, LIU Wenting, YANG Xiaoxia, FENG Bin, SUN Caicai, LI Caidi, ZHAO Xinquan, DONG Quanmin

2024, 43(1):  57-65.  doi:10.13292/j.1000-4890.202401.031

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To understand how livestock assemblage regulates aboveground net primary productivity in alpine grasslands under moderate grazing intensity and improve the management standards of alpine grasslands, we conducted an experiment with different livestock assemblages (yak and Tibetan sheep grazing alone and 1∶2 mixed grazing) under moderate grazing intensity and no grazing as the control in an alpine grassland on the eastern Qinghai-Tibet Plateau. We analyzed the changes in plant community characteristics, soil physicochemical properties and aboveground net primary productivity. The results showed that livestock assemblages did not affect species richness and diversity index, but significantly reduced the height and coverage of plant communities, and changed the proportions of importance values of different functional groups. Tibetan sheep grazing alone significantly increased soil available N and P content and soil bulk density of alpine grassland. Grazing weakened the regulation of species diversity on aboveground net primary productivity but strengthened the effect of soil environmental factors. The aboveground net primary productivity and livestock intake were the highest under the mixed grazing. To improve the management standard of alpine grasslands, it is recommended to carry out mixed grazing of yaks and Tibetan sheep in appropriate proportions based on moderate grazing intensity and to adopt coupled vegetation wivestock soil management to achieve sustainable use and maintain ecological function of alpine grasslands.





Responses of the epigeic springtails and mites to the degradations of alpine meadow.

TANG Sisi, YOU Guangnian, WEI Xue, REN Xiao, CHEN Yan, WANG Yuying, WU Pengfei

2024, 43(1):  66-74.  doi:10.13292/j.1000-4890.202401.032

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To understand the effects of alpine meadow degradation on the composition and diversity of epigeic springtail and mite communities, we investigated epigeic springtail and mite communities in swampy meadow, grassland meadow, and moderately degraded meadow of Zoigê wetland using motor-sucking in July and October 2018. A total of 13640 springtail individuals, belonging to 4 orders, 11 families and 23 genera, were collected, with Sminthurinus and Desoria being the dominant taxon. A total of 5069 mite individuals, belonging to 3 suborders, 76 families and 98 genera (taxonomic groups), were collected, with Eupodidae as the dominant group. Results of principal component analysis showed that the taxonomic composition of springtail and mite communities differed remarkably among different habitats. With increasing degradation degree, the abundance and taxonomic richness of mites increased (P<0.05), the abundance of springtails increased significantly (P<0.05). The abundance and Simpson index of springtails were significantly higher in July than those in October (P<0.05) across the three habitats, while the opposite patterns were found for the taxonomic richness and Shannon index. Regarding to epigeic mites, the abundance and taxonomic richness were significantly higher in July than those in October (P<0.05), without seasonal variation in Shannon and Simpson dominance index (P>0.05). The results of redundancy analysis and multiple regression analysis showed that the taxonomic composition, abundances and diversity index of epigeic springtails and mites were mainly influenced by the specie richness and biomass of plant communities and soil bulk density, but the effects differed between springtails and mites. Our results demonstrated that degradation and seasonal changes had significant effects on the taxonomic composition, abundance and diversity index of epigeic springtail and mite communities. The springtails responded more sensitively to seasonal changes than mites, and the mites were more significantly affected by the degradation of alpine meadows than springtails.





Spatial heterogeneity of plant community and its influencing factors in Longxiang Mountain.

QI Shang, LIU Zhanshi, DU Dan, LIN Qingwei, HUAI Zhiwen, HUANG Yongwen, ZHNAG Ganggang, MA Jianmin

2024, 43(1):  75-85.  doi:10.13292/j.1000-4890.202401.004

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To clarify the spatial distribution and interspecific relationship of plant community in Longxiang Mountain in Jiaozuo, Henan, we investigated the species composition, diversity, niche and interspecific association of plant communities by means of interspecific association analysis, regression analysis, and non-metric multidimensional analysis (NMDS). Results showed that 172 species belonging to 128 genera and 57 families were recorded. Among those species, 28 species belonged to 24 genera and 15 families in arbor layer, 25 species belonged to 22 genera and 16 families in shrub layer, and 111 species belonged to 86 genera and 33 families in herb layer. In the arbor layer, Tamarix chinensis had the highest importance value (1.523), while Cotinus coggygria had the maximum niche width (4.763). For shrub and herb layers, Gleditsia microphylla and Carex rigescens had the highest importance value (0.483 and 0.429), and their niche width ranked 2 nd and 5 th, respectively. Total coverage (83%), Simpson index (0.605) and Shannon index (1.875) in shady slope were higher than those in sunny slope, and significantly higher than those in flat slope (P<0.05). Margalef diversity index (1.315) and evenness index (1.084) were the highest at altitude of 500-600 m. Altitude had significant power exponential and quadratic polynomial relationships with Margalef diversity index and evenness, respectively (P<0.05), while slope gradient had a quadratic polynomial relationship with Margalef diversity index and Shannon index (P<0.05). The niche overlap index of dominant plant species was positively correlated with interspecific association indices (Dice index, Jiaccard index and Ochiai index) (P<0.05), indicating that the dominant plant species in Longxiang Mountain were temporally and spatially associated, and species pairs were positively correlated with each other. Results of NMDS analysis showed that plant community composition and diversity varied among different altitudes and slopes. Our results can provide reference for the utilization, protection, and management of plant resources in mountain areas of Jiaozuo.





Responses of seedlings to light temporal heterogeneity in different habitats.

WANG Deng, WANG Shu, WANG Yeshe

2024, 43(1):  86-95.  doi:10.13292/j.1000-4890.202401.040

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The influences of light spatiotemporal heterogeneity on plants have long been recognized. However, previous researches have mostly focused on responses of plants to spatially heterogeneous light conditions, little is known about how plants respond to temporally heterogeneous light conditions. Taking 1-year-old seedlings of Kmeria septentrionalis from karst habitats, Lithocarpus glaber from non-karst habitats and Celtis sinensis that occur in both habitats as objects, we compared the variations of morphological, biomass and physiological characteristics of the three species under the treatments of temporally heterogeneous light (alternating full light and heavy shading) and temporally homogeneous light (constant moderate shading and full light), to explore their responsive ability and strategies in coping with light environmental changes. Compared to moderate shading, temporal heterogeneity in light conditions increased basal diameter and decreased total biomass. Compared to the treatments of full light and moderate shading, light temporal heterogeneity treatments increased the content of osmotic substances and malondialdehyde and antioxidant enzyme activity. At the early stage, light temporal heterogeneity treatments led to an increase in the osmotic pressure of plant cells and the degree of membrane lipid peroxidation, which inhibited plant growth, but ultimately increased the daily accumulation rate of total biomass under shading. The contents of osmotic regulators and antioxidant enzyme activities of plants were reduced. The malondialdehyde content of K. septentrionalis (from karst habitat) was most stable in temporally heterogeneous light conditions, while the daily accumulation rate of total biomass was the highest at the end of treatment. In summary, the acclimation convergence of the three species in response to the same light conditions is closely related to their early experience of light availability. K. septentrionalis has evolved the corresponding responsive mechanisms in its long-term adaptation to karst habitats, it may therefore have stronger adaptability to temporally heterogeneous environments than the other two species. Such ability may be the most limited for L. glaber (from non-karst habitats).





Effects of altered seasonal precipitation distribution on root morphological traits of different function-type seedlings in a tropical secondary forest. 

HE Zhihang, LIU Yue, TAO Yuzhu, WU Miaolan, GAO Chang, WANG Yiying, YU Yaohong, ZHOU Qing, MO Qifeng

2024, 43(1):  96-105.  doi:10.13292/j.1000-4890.202401.001

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Precipitation seasonal distribution and intensity have been significantly changed according to the forecast on global precipitation pattern. To explore how the precipitation seasonal distribution affects the growth and root morphology of seedlings in a tropical secondary forest, a precipitation simulation experiment with three treatments, delay wet season (DW), wetter wet season (WW), and control (CT, ambient precipitation), was established in Dianbai District, Maoming City of Guangdong Province, to address the responses of root morphological traits of different function-type seedlings (N-fixing and non-N-fixing) to the changes in precipitation seasonal distribution. The results showed that WW treatment significantly increased fine root length, surface area, volume, biomass, and specific root length (SRL) of the seedlings of the five species. WW treatment significantly decreased fine root length and SRL, and coarse root SRL of Cinnamomum camphora. WW treatment significantly increased coarse root length, surface area, volume, and biomass of Syzygium hancei, and significantly increased coarse root volume and average diameter of Acacia auriculiformis. WW treatment significantly increased fine root length, surface area, volume, and biomass of two N-fixing tree species (Cassia siamea and A. auriculiformis), and increased fine root average diameter of C. siamea. Additionally, WW treatment significantly increased fine root length of S. hancei, coarse root volume of S. jambos, and fine root biomass of C. camphora and S. hancei. DW treatment had minor effects on root morphological traits. It significantly decreased coarse root length of C. camphora, coarse root surface area of A. auriculiformis, SRL of C. camphora fine root and S. jambos coarse root; increased the coarse root volume and average diameter of S. hancei, coarse root volume of C. siamea, and coarse average diameter of S. jambos. N-fixing species had higher root biomass and volume under DW and WW treatments than under CT. These results suggest that the roots of five species can be tolerant to drought (delayed wet season) to some extent. Fine roots are more sensitive to WW treatment than coarse roots. WW treatment has greater effects on fine root morphology of N-fixing tree species rather than non-N-fixing tree species, indicating that N-fixing tree species are more adaptable to abnormal rainfall. Root morphology of understory seedlings in tropical secondary forest can well adapt to the changes of seasonal distribution of rainfall, with consequence on community regeneration and stability.





Combined impacts of urbanization and edge effects on the phylogenetic characteristics of woody plants in urban remnant forests in Guiyang.

PAN Ying, WANG Zijin, YANG Jingyi

2024, 43(1):  106-114.  doi:10.13292/j.1000-4890.202401.012

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Urban remnant forests have a high value in biodiversity conservation. The knowledge about the relationship between urbanization and phylogenetic characteristics of woody plants can help reveal the maintenance mechanism of biodiversity in urban remnant forests. We surveyed species composition of woody plants in 72 plots of nine remnant forest patches in a southwest mountain city-Guiyang, China. We calculated the phylogenetic parameters of plant communities. We used Tukey test, paired t-test, and analysis of similarities to explore the combined impacts of urbanization and edge effects on the phylogenetic characteristics of woody plants in urban remnant forests. We found high phylogenetic diversity of shrub communities and an aggregation trend of phylogenetic structure. The edge effects at sapling/seedling layer were significant under high levels of urbanization. Urbanization level had more influence on the phylogenetic characteristics of plant communities in edge habitats than in inner habitats. The phylogenetic structure of plant communities in the edge habitats under high urbanization levels was significantly different from that in the inner habitats under low urbanization levels. Both the urbanization level and edge effects influenced the phylogenetic characteristics of plant communities in remnant forests. We recommend that urban expansion surrounding remnant patches should be strictly controlled to alleviate edge effects on the phylogeny of remnant vegetation.





Effects of waterlogging on the photosynthetic characteristics of Phyllostachys heteroclada.

LUO Huiying, SU Wenhui, LIN Xiaoyun, CHU Haoyu, JIN Yi, JING Xiong, SUN Yutong, LONG Yongmei

2024, 43(1):  115-121.  doi:10.13292/j.1000-4890.202401.013

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To explore the photosynthetic physiological responses of Phyllostachys heteroclada, a waterlogging-tolerant and fast-growing bamboo species, to different degrees of waterlogging stress, we measured the photosynthetic gas exchange parameters, photosynthetic pigments and leaf resource use efficiency of one-year-old P. heteroclada to the degree of waterlogging stress and duration of waterlogging under three treatments: normal watering (as control), half flooding, and full flooding. After waterlogging for three days, net photosynthetic rate, light saturation point and transpiration rate of P. heteroclada under half flooding increased significantly compared with the control, but there was no change under full flooding. With the extension of stress duration, all the variables decreased, with the decreasing range being positively correlated with the degree of stress. After waterlogging for six days, stomatal conductance of P. heteroclada leaves was significantly higher than that of the control, and then showed a downward trend. The intercellular CO₂ concentration showed a trend of decreasing first and then increasing, and the difference with the control was not significant by day 9. The recovery time was positively correlated with the degree of stress. Dark respiration rate and light compensation point increased with increasing stress duration. The content of total photosynthetic pigments showed a trend of decreasing first and then increasing with the duration of stress. The ratio of chlorophyll to carotenoid remained at 3∶1, while the ratio of chlorophyll a to chlorophyll b decreased from 3∶1 to 2∶1. Leaf water  use efficiency showed a trend of decreasing and then increasing. Both the apparent energy utilization rate and apparent CO₂ utilization rate showed a decreasing trend, and their decreasing rate gradually decreased with the extension of waterlogging duration. Our results indicated that photosynthesis of bamboo showed certain promoted effects under half flooding stress. With the extension of stress duration, the photosynthetic parameters gradually decreased to stable levels, and bamboo showed certain waterlogging tolerance by adjusting the ratio of photosynthetic pigments and improving water use efficiency. After adapting to the flooded environment, photosynthetic pigments began to recover.





Effects of rainfall reduction on stem sap flow of Robinia pseudoacacia.

GUO Haining, LIU Meijun, DU Sheng

2024, 43(1):  122-130.  doi:10.13292/j.1000-4890.202401.020

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Under the background of global climate change, regional precipitation pattern is changing, with consequences on forest ecosystem productivity and hydrological processes. To investigate the effects of rainfall reduction on the characteristics of transpiration water use and their responses to environmental factors in trees, we applied rainfall reduction treatment to a plantation of black locust (Robinia pseudoacacia), a major afforestation species, in a sub-humid region of Loess Plateau. Transparent waterproof panels were laid out in the inter-rows of the rainfall reduction plot to reduce the rainfall input by 47%. Stem sap flow was measured by Granier’s thermal dissipation probes. Environmental factors including solar radiation, air temperature, relative humidity, rainfall events and soil moisture were monitored simultaneously. The response characteristics of stem sap flow to rainfall reduction and seasonal soil moisture changes were analyzed. The results showed that rain reduction significantly reduced the norma-lized sap flux density of black locust trees. After three years of treatment, normalized sap flux density in the rain reduction treatment was significantly lower than that in the control. The diurnal peak time of the normalized sap flux density in the rain reduction plots was earlier than that in the control, indicating that stomatal adjustment occurred earlier and that the time lag between sap flow and meteorological factors was changed. The fitting equation parameters of normalized sap flux density response to transpiration driving factors were significantly different between both treatments, indicating that the sensitivity of black locust response to meteorological factors in the treatment of rain reduction was weakened. These results suggest that precipitation changes not only affect forest soil water availability, but also affect the transpiration characteristics of black locust trees and their responses to environmental factors.





Responses of leaf functional traits in typical shrubs to environmental factors in the Daxing’an Mountains, Northeast China.

BAI Yansong, ZHANG Yujian, QIN Qianqian, SUN Xingyue, LIU Yanhong

2024, 43(1):  131-139.  doi:10.13292/j.1000-4890.202401.025

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Nine leaf functional traits of four shrub species (Rhododendron dauricum, Ledum palustre, Vaccinium vitis-idaea, Spiraea salicifolia) in Daxing’an Mountains were measured to explore the relationships between leaf functional traits and environmental factors and reveal ecological adaptation strategies of shrubs. Leaf functional traits were significantly different among species (P<0.05). L. palustre and V. vitis-idaea had larger leaf thickness (0.279, 0.305 mm, respectively), smaller specific leaf area (220.95, 211.90 cm²·g^-1, respectively), and higher leaf dry matter content (0.463, 0.384 g·g^-1, respectively) than the other two species, which indicated that they have relatively high resource use rate and strong adaptability to the environment. In contrast, R. dauricum and S. salicifolia maintained their ability to synthesize organic matter by reducing leaf thickness and increasing specific leaf area. Specific leaf area of the four species was significantly negatively correlated with leaf thickness and leaf tissue density. In addition, the specific leaf area of R. dauricum, L. palustre and S. salicifolia was significantly negatively correlated with leaf dry matter content. Leaf functional traits of R. dauricum, L. palustre, V. vitis-idaea were mainly affected by topographic factors, whereas those of S. salicifolia were mainly affected by soil factors. Elevation was the key factor affecting leaf functional traits of R. dauricum and V. vitis-idaea (with an explanation rate of 26.5%), soil water content was the key factor affecting that of L. palustre (with an explanation rate of 14.3%), and soil bulk density and soil total N were the key factors affecting that of S. salicifolia (with an explanation rate of 15.6%). Although the interspecific differences are significant in leaf functional traits of the typical shrubs in Daxing’an Mountains, they can well adapt to the environment by forming a suite of traits and interacting with environmental factors.





Effects of drought and shading on instantaneous water use efficiency and δ¹³C of Pinus massoniana seedlings.

DENG Xiuxiu, SHI Zheng, ZENG Lixiong, LEI Lei, PEI Shunxiang, WU Sha, XIAO Wenfa

2024, 43(1):  140-145.  doi:10.13292/j.1000-4890.202401.027

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Water use is a key process of photosynthetic carbon sequestration in plants. δ¹³C is a key indicator for long-term water use efficiency (WUE), reflecting the adaptive ability of plants to stressful environments. It is thus of great significance to reveal the long-term relationship between plants and environment. In this study, we examined the effects of drought and shading on instantaneous WUE and δ¹³C in Pinus massoniana seedlings under four treatments, including drought (30% saturated water content of soil moisture), shading (30% of full light intensity), drought + shading (30% saturated water content of soil moisture and 30% of full light intensity), and CK (70% saturated water content of soil moisture and full light intensity). The instantaneous WUE in the current-year needles significantly increased by 67.96% and 60.78% under drought and combined stress, respectively. δ¹³C significantly increased by 14.35% under drought, but did not significantly change under shading and combined stress. However, the δ¹³C values did not significantly change in the 1-year-old needles under three treatments. This indicated that the changes of instantaneous and long-term water use efficiency were not synchronized in P. massoniana, with WUE responded earlier to drought. The δ¹³C value in sink organs was higher than that in the source needles under all treatments. Moreover, δ¹³C in stems and roots had significant correlation with that in needles, which was significantly positively correlated with that in 1-year-old needles. The δ¹³C value in sink organs was also mainly influenced by the supply of source needles. These results implied that the changes in WUE caused by changing environments could further affect δ¹³C in each sink organ, which would provide a reference for the understanding the mechanism underlying the responses of P. massoniana seedlings to climate change.





The differentiation process of flower bud and the changes of endogenous hormones in Syringa microphylla.

XU Xin, LIU Jiaqi, WANG Yuhan, SONG Lu, LIANG Yan

2024, 43(1):  146-152.  doi:10.13292/j.1000-4890.202401.037

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Observing the process of flower bud differentiation, clarifying the correlation between morphology and anatomical structure of flower buds, and analyzing the dynamic changes of endogenous hormones can provide scientific basis for flowering regulation and cultivation management of Syringa microphylla. In this study, we examined flower bud differentiation and flowering characteristics of S. microphylla by external morphological observation and paraffin section technology, and measured the contents of endogenous hormones by enzyme-linked immunization (ELISA). According to the observation results of anatomical structure, flower bud differentiation of flowered S. microphylla in spring began in late May and ended in early October. The flower bud differentiation process could be divided into seven stages: undifferentiated stage, spathe primordium differentiation stage, inflorescence primordium and small floral primordium differentiation stage, sepal primordium differentiation stage, petal primordium differentiation stage, stamen primordium differentiation stage, and pistil primordium differentiation stage. There were overlaps across different differentiation stages. Indole acetic acid (IAA), abscisic acid (ABA) and zeatin riboside (ZR) changed greatly and showed a variation pattern of “down-up-down”, “up-down-up-down” and “up-down”, respectively. The content of gibberellin (GA₃) remained stable at a low level with little variation  throughout the whole process. The highest value of ABA/GA₃ appeared in the differentiation stages of spathe primordium, sepal primordium, and petal primordium. The highest value of IAA/GA₃ appeared in the undifferentiated stage, the inflorescence primordium and small floral primordium differentiation stage, and the petal primordium differentiation stage. The highest value of ABA/IAA appeared in the sepal primordium differentiation stage, while the highest values of ZR/GA₃ and ZR/IAA appeared in the differentiation stages of sepal primordium and petal primordium. The internal anatomical structure of flower bud differentiation was closely related to the external morphology. High levels of IAA, ABA, ABA/GA₃ and IAA/GA₃ were beneficial to the initiation of flower bud differentiation and the differentiation of early flower organ primordium, while the differentiation of sepal primordium and petal primordium required the accumulation of ZR, IAA, and ABA. The initiation stage of flower bud differentiation and the differentiation of sepal primordium and petal primordium may be the key periods of flower bud differentiation of S. microphylla, with an important role of the content of endogenous hormones and the balance between hormones.





Ion balance of Populus euphratica under different habitats and its relationship with soil factors.

WANG Jie, HEI Yulong, HUANG Wenjuan, WANG Xin, LI Pengfei, YAO Shiyu, PENG Chengzhi

2024, 43(1):  153-161.  doi:10.13292/j.1000-4890.202401.038

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The purpose of this study was to explore the ion distribution in organs of Populus euphratica adapting to saline environment and to reveal the physiological mechanism of salt-tolerance of P. euphratica. We measured the contents of Na⁺, K⁺, Ca²⁺, and Cl^- in root, trunk, old branch, young branch, and leaf of P. euphratica in high and low-salt habitats, and analyzed the differences in absorption, transport and distribution characteristics of various ions and their relationships with soil factors. The results showed that: (1) Foliar Na⁺ and Cl^- contents in high-salt environment were significantly lower than those in low-salt environment, while foliar K⁺ content was significantly higher than that of low-salt environment. However, no significant differences in contents of the ions in other organs were observed between those two habitats. The K⁺/Na⁺ of old branches, young branches, and leaves of P. euphratica in high-salt environment was significantly higher than that in low-salt environment, but the difference of Ca²⁺/Na⁺ was not significant. While the ability of roots to selectively absorb K⁺ in high-salt environment was significantly weaker than that in the low-salt environment, the ability to absorb Ca²⁺ was stronger, and the ability of other organs to selectively transport Ca²⁺ and K⁺ upward was also stronger in high-salt environment. (2) In low-salt environment, Na⁺, K⁺, and Cl^- were mainly distributed in leaves, and Ca²⁺ was mainly distributed in roots. The ability of trunk to selectively transport K⁺ and Ca²⁺ to young and old branches was stronger in low-salt environment than that in high-salt environment. In high-salt environment, Na⁺ and Ca²⁺ were mainly distributed in roots, and K⁺ and Cl^- were mainly distributed in roots and leaves. Roots had stronger ability to transport K⁺ and Ca²⁺ to old branches and young branches. (3) Na⁺ content in the roots and K⁺ content in aboveground organs of P. euphratica were significantly positively correlated with most soil factors. Root K⁺ content was negatively correlated with Na⁺ content in aboveground parts and most soil factors. The content of Ca²⁺ in trunk was negatively correlated with soil total salt content, electrical conductivity, and Na⁺ content. The content of Cl^- in young branches and trunks was significantly correlated with soil HCO₃^- and SO₄^2- contents. Soil water content was positively correlated with root Na⁺ content, and negatively correlated with root K⁺ content. Our results suggested that P. euphratica adapted to different saline environments mainly by regulating the allocation of salt ions in different organs, the separation and restriction of roots and leaves, and the ions regulation by branches, thus ensuring the ion balance and normal physiological metabolism in P. euphratica.





Changes in C, N, and P stoichiometry of soil and plant of poplar plantations in Horqin Sandy Land.

WANG Kai, XING Shiqi, ZHANG Risheng, LYU Linyou, LIU Chang

2024, 43(1):  162-169.  doi:10.13292/j.1000-4890.202401.023

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To understand the variations of carbon (C), nitrogen (N), and phosphorus (P) stoichiometry in poplar plantation and the effects of stand development on the element cycle between plant and soil, we measured C, N, and P concentrations and their ratios in different organs (leaf, stem, and root), leaf litter and soil in young and mature poplar plantations. N and P resorption efficiencies were calculated, and the correlations of C, N, and P between plant and soil were explored. The results showed that N and P concentrations decreased in the order of leaf>root>branch for young trees, whereas they were higher in leaves and branches than roots in mature trees. C∶N, C∶P, and N∶P in leaves and branches, and N and P concentrations in roots were higher, but N concentrations in branches, P concentrations in leaves and branches, and C∶N and C∶P in roots were lower in young trees than in mature trees. Leaf litter N and P concentrations of young trees were lower than those of mature trees, while C∶N and C∶P of young trees were higher than those of mature trees. N resorption efficiency was higher but P resorption efficiency was lower in young trees than in mature trees. Soil C and N concentrations increased but soil P concentrations decreased at 0-40 cm layer after poplar afforestation. N and P concentration in both branch and root was positively correlated with soil N and P concentration, respectively. These results indicated that young poplar trees tended to supply more N and P to roots, and decrease the loss of N and P in leaf litter, which would contribute to rapid growth. However, mature trees allocated more N and P to leaves and branches, and increased the return of N and P from leaf litter to soil, so as to promote the nutrient cycle between trees and soil. The growth of young poplar trees was mainly restricted by N, while that of mature trees was mainly restricted by P in Horqin Sandy Land.





C, N, and P stoichiometric characteristics of fine root and soil in different stand types on the north slope of Changbai Mountain.

ZOU Jiahe, WANG Haiyan, LI Chengming, CUI Xue, ZHAO Han, CHEN Yue, DONG Qiqi, HOU Wenning

2024, 43(1):  170-177.  doi:10.13292/j.1000-4890.202401.039

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Fine roots are the main organ for plants to absorb nutrients and water, and their decomposition  is an important pathway for soil nutrient return. Studying the stoichiometric characteristics of fine roots is of great significance for understanding plant-soil nutrient cycle in forest ecosystems. This study focused on the middle-aged natural Mongolian oak forest, natural broad-leaved mixed forest and larch plantation in Bajiazi Forestry Bureau, Jilin Province. Based on the stand survey data of 15 plots of 30 m × 30 m, the C, N, P stoichiometric characteristics of fine roots and soils (0-20 cm) in different stand types and their relationships were analyzed. The results showed that fine-root and soil C, N, P stoichiometric characteristics differed across different stands (P<0.05). Fine roots of all the three stand types were limited by N. Soil nutrients were rich in the natural broad-leaved mixed forest, but soil P of the natural Mongolian oak forest were relatively poor. The correlations between fine-root and soil C-N-P stoichiometric characteristics were significantly higher in larch plantation and natural broad-leaved mixed forest than that in the natural Mongolian oak forest. As for the three stand types, fine-root C∶N, C∶P, and C were more affected by soil C-N-P stoichiometric characteristics with soil C∶P as the major affecting factor. Our results provide a certain theoretical basis for soil nutrient management and sustainable forest management of natural Mongolian oak forest, natural broad-leaved mixed forest and larch plantation in Changbai Mountain forested area.





Comprehensive evaluation of drought tolerance of different cultivars (lines) of potatoes and screening of the indicators.

XING Yuan, LI Kaifeng, ZHOU Jinhua, GUO Huachun, LI Jun

2024, 43(1):  178-187.  doi:10.13292/j.1000-4890.202401.007

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In this study, four potato cultivars (lines) were treated with two simulated drought conditions, namely, artificial water control in pot culture and PEG6000 stress in tissue culture. The differences of their drought tolerance were evaluated by morphological and physiological indices, aiming to provide the basis for potato resistant cultivation and breeding of drought-tolerant cultivars. Normal irrigation (CK) and two drought stress treatments were set up in potted planting including moderate drought (T1, relative soil moisture index 45%±5%) and mild drought (T2, relative soil moisture index 55%±5%). Four PEG-6000 levels (5%, 10%, 15%, 20%) were set up for the tissue culture seedlings. We measured the average yield per plant, nine morphological indicators, and six physiological indicators of the potted planting potatoes. Three methods were used to analyze the experimental data. The drought tolerance of the tested materials was preliminarily evaluated and verified by tissue culture seedlings. The results showed that the drought-tolerant germplasms screened by two different simulated drought treatments were consistent. Drought-tolerant cultivars (lines) were the advanced strain D1520 and “Dianshu 97”, and drought-sensitive cultivars were “Qingshu 9” and “Dianshu 1418”. Seven indicators that were more sensitive to drought stress were identified from fifteen indicators, including abscisic acid content, peroxidase activity, number of leaves, plant height, number of nodes, number of branches, and leaf angle. Among them, number of leaves of each cultivar (line) could be used as an important index for drought-tolerant evaluation after being verified by the tissue culture experiment.





Spatiotemporal variations and driving forces of soil pH in peanut planting area in southern Henan Province.

SUO Yanyan, ZHANG Xiang, WU Shiwen, SI Xianzong, LI Liang, XU Fengdan, CHENG Peijun, LI Qian

2024, 43(1):  188-196.  doi:10.13292/j.1000-4890.202401.002

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Exploration of the characteristics and driving factors of soil acidification in peanut planting areas is of great significance in providing theoretical basis for the improvement of peanut planting soil acidification. Soil pH and its driving factors in Zhengyang County, a typical peanut planting area in southern Henan were obtained through data collection and field sampling methods. The temporal and spatial variations of soil pH were analyzed using GIS technology. Their key influencing factors were identified by the boosted regression tree (BRT) model. The results showed that soil pH of peanut planting area in Zhengyang County generally showed a decreasing trend. Soil pH declined from 7.06 in 1980 to 5.15 in 2020. The area of weakly alkaline and neutral soil decreased significantly, while the area of acidic soil increased. From 1980 to 2020, the variation range of soil pH with the largest change in area was -2.0 to -1.5, accounting for 51.9% of the whole county’s area. The most serious soil acidification occurred in lime concretion black soil, while soil pH decreased to a lesser extent in paddy soil and fluvoaquic soil. The BRT analysis showed that cation exchange capacity (CEC) was the most important factor affecting the spatial variation of soil pH in 2020, with a contribution rate of 26.2%, followed by available potassium content (AK), annual mean precipitation (AMP), soil organic matter content (SOM) and total nitrogen content (TN), with contribution rates of 11.0%, 7.7%, 7.2%, and 6.9%, respectively. Soil pH increased with increasing soil CEC, AMP, AK and SOM, but decreased with increasing soil TN. In conclusion, soil acidification of summer peanut planting in Zhengyang County is serious, especially in lime concretion black soil region, and with the characteristics of universality and local severity. Among all the factors examined, CEC is the most important driving factor for the spatial variation of soil pH. In the future, water and fertilizer management should be optimized to improve soil organic matter and nitrogen use efficiency by maintaining the balance of base ion pool in soil, so as to effectively inhibit soil acidification in peanut planting areas.





Change and potentiality prediction of forest carbon sink and its economic value in Heilongjiang Province.

XU Siruo, CHENG Zhiying, NA Xueying, ZHANG Xujia, MA Dalong, ZHANG Peng

2024, 43(1):  197-205.  doi:10.13292/j.1000-4890.202401.008

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In the vision of carbon neutrality, quantifying forest carbon sinks helps to make forest carbon strategies as well as carbon trading mechanisms, and enhance resistance to climate change, which plays a key role in safeguarding national ecological safety, achieving the goal of carbon neutrality, and slowing down global warming. Based on data collected from national forest inventory, we analyzed the trends of forest carbon stocks and carbon sinks in Heilongjiang Province from 1999 to 2018, using the continuous function of biomass conversion factors and the carbon tax method. Further, prediction for the carbon stocks of arbor forests was made using GM (1,1) model in order to obtain the predicted carbon sinks and their economic value in the year achieving the target of carbon peak. The results showed that forest carbon stocks of Heilongjiang increased from 696 billion kg in 1999-2003 to 914 billion kg in 2014-2018, with arbor forests accounting for 99.51%-99.65% of the total forest carbon stocks. Overall, the carbon sink of arbor forests in Heilongjiang Province presents an upward trend from 1999 to 2018, increasing from 16.8 billion kg·a^-1 in 2004-2008 to 17.6 billion kg·a^-1 in 2014-2018. The economic value of carbon sink shows a downward trend from 2.06 billion yuan·a^-1 in 2004-2008 to 1.66 billion yuan·a^-1 in 2014-2018 due to the variation of exchange rate. During the study period, the average carbon sink of mature forest is the largest among various age groups, and the broadleaved mixed forest is the major contributor to the forest carbon sink, accounting for 93.93% of the total carbon sink of arbor forest. With the enhancement of the afforestation, the proportion of carbon sink of the plantation forest will increase. The carbon sinks of arbor forests and their economic value in Heilongjiang by 2030 are predicted to be 18 billion kg·a^-1 and 1.89 billion yuan·a^-1, respectively.





Effects of land use/cover change on land surface temperature in new mountainous city: A case study of Yuelai New City, Chongqing.

ZHANG Qin, ZHANG Shouping, YANG Qingwei

2024, 43(1):  206-215.  doi:10.13292/j.1000-4890.202401.010

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To understand the impacts of land use/cover change on land surface temperature during the urbanization of new development zones in mountainous cities, we analyzed the spatial distribution of land use type, normalized difference vegetation index (NDVI) and land surface temperature (LST) of Yuelai New City in Chongqing before, during and after urbanization, by interpreting the historical images with remote sensing. Further, the effects of land use type change and NDVI change on LST were analyzed. The residential combined land expanded greatly during urbanization, mainly occupying farmland, followed by forest land. Overall, vegetation grew better after urbanization than before urbanization. The coverage of farmland and forest land increased, while that of residential combined land decreased significantly. LST had obvious heterogeneity in different land use types and regions, and was sensitive to urbanization process, which was more obvious in summer and winter. There was a significant linear correlation between LST and land use area. There was no significant relationship between LST and NDVI, but the shapes of their spatial relationships were triangular in the three periods. Vegetation cover could mitigate the heat island effect. The results could provide theoretical basis for ecological planning and the mitigation of heat island effect during urbanization in new development zones in mountainous cities.





Assessment of the impact of grassland quality on herdsmen livelihood vulnerability in Inner Mongolia.

GE Rileqimuge, WU Lantuya, SI Qinchaoketu, BAO Musu

2024, 43(1):  216-223.  doi:10.13292/j.1000-4890.202401.018

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Grassland is an important terrestrial ecosystem and a major resource for livestock husbandry. Increasing degradation has damaged the ecological environment of grasslands, seriously affecting their sustainability. This puts enormous pressure on the livelihoods of herders. A systematic analysis of the impacts of grassland quality on the livelihood of herders’ households is important for formulating effective policies for grassland rehabilitation, enhancing the adaptability of pastoral households to grassland degradation, and reducing the livelihood vulnerability of the poor in pastoral areas. In typical grassland areas in Inner Mongolia, field sampling data in 2017 and 2019 and herding household interview data in 2021 were used to construct an index system for evaluating the livelihood vulnerability of herding households based on the impact of grassland quality. The index was used to analyze the key factors affecting the livelihood vulnerability of herding households. Pure herding, herding combined, and non-herding households in typical grassland areas of Inner Mongolia did not differ significantly in pasture area and per-capita income. Labor force of pure herding and herding combined households was richer than that of non-herding households. The livelihood vulnerability of pure herding and non-herding households was higher than that of herding combined households. Grassland quality was a key factor affecting the livelihood vulnerability of pure herding households. Restoration of the grassland’s ecological environment could reduce the livelihood vulnerability of herders. Developing diversified livelihoods based on herding and improving the health level and credit capital of households would be conducive to reducing the livelihood vulnerability of herding households.





Evaluation for ecological services of macroalgae in the seaweed beds of the eastern coastal waters of Shenzhen, China.

HU Shanshan, ZOU Dinghui, ZHOU Kai, WANG Zhiyu

2024, 43(1):  224-233.  doi:10.13292/j.1000-4890.202401.005

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Seaweed beds play an important role in marine ecosystem, with unique ecosystem services value. We evaluated the importance of specific indices of ecological services of macroalgae in the seaweed beds of the eastern coastal waters of Shenzhen, China. Based on the previous survey of seaweed bed resources, their ecological values were evaluated using the market valuation method, alternative cost method, and contingent value method. The results showed that the importance of the specific indices of ecological services of macroalgae in the seaweed beds of four eastern coastal waters of Shenzhen was in an order of carbon sequestration and oxygen release > biodiversity maintenance > removal of N and P > material production > absorption of heavy metals > scientific research. The mean annual biomass of macroalgae was 10427.42 g·m^-2, the area of seaweed beds was 14.55 hm², and the total resource of macroalgae was 3983.90 t·a^-1. The total value of ecological services was 2.49 billion yuan·a^-1, with a per unit area value of 117 million yuan·hm^-2·a^-1. The ecological services value of macroalgae in the seaweed beds was 714, 587, 553, and 637 million yuan·a^-1 for Xiaomeisha, Qixing Bay, Yangmeikeng-Luzui, and Dongchong-Xichong, respectively, and accounted for 28.67%, 23.58%, 22.19%, and 25.56%. The quantification of the ecological values of macroalgae in the seaweed beds is helpful for protecting seaweed beds, which provides data support for the construction of marine pastures and related economic strategic decisions. Meanwhile, our evaluation method can provide reference for the formulation of the evaluation standard of ecosystem services of seaweed beds in China.





Comparative analysis of gut microbiome diversity and functional characteristics of four desert jerboas in Xinjiang.

TUOLIU Dilala, CHENG Jilong, XIA Lin, YANG Weikang, YANG Qisen

2024, 43(1):  234-243.  doi:10.13292/j.1000-4890.202401.014

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Gut microbiome is an important integral for maintaining body health. Clarifying the diversity of animal gut microbiome is helpful to understanding the ecological adaptation of animals. It has been reported that gut microbiomes of desert gerbils contribute to their adaptation to the desert environment. However, the structure, diversity, and function of gut microbial community of jerboas, which are widely distributed in the desert environment, are still unclear. In this study, we used 16S rRNA high-throughput sequencing technology to compare the gut microbiome composition and function of Northern three-toed jerboa (Dipus sagitta), Siberian jerboa (Orientallactage sibirica), long-eared jerboa (Euchoreutes naso), and Kozlov’s pygmy jerboa (Salpingotus kozlovi), which represent the four subfamilies in Dipodidae living in desert areas of Xinjiang. A total of 1557065 valid sequences were obtained, and 2708 ASV were identified, belonging to 20 phyla, 50 classes, 71 orders, 142 families, and 336 genera. Among the alpha diversity indices, ACE index, and Chao1 index of Dipus sagitta and Salpingotus kozlovi were significantly lower than those of the other two species, while Shannon index and Simpson index were similar in four species. The results of principal coordinate analysis (PCoA) showed that the gut microbiome structure of the four jerboa species was significantly different. LEfSe analysis showed that there were 10 significantly different bacterial genera in the gut microbiome of the four jerboa species, most of which belonged to Bacteroides. Results of PICRUSt analysis showed that the gut microbiomes of four jerboa species had similar functions and mainly participated in the metabolic process of the host. Our results uncovered the gut microbiome characteristics of four species of jerboa in desert areas, providing basic data for further study on the formation of gut microbiome structure and physiological and ecological adaptation of desert jerboas.





Research progress on the valuation of forest ecosystem services in China during 2010 to 2021.

YANG Haijiang, GOU Xiaohua, TANG Chengrui, XUE Bing

2024, 43(1):  244-253.  doi:10.13292/j.1000-4890.202401.026

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Evaluating the service functions of forest ecosystems is conducive to realizing the capitalization of forest resources and optimizing the protection and management of forest resources. In this study, we reviewed the research progress on the evaluation of the service function value of forest ecosystems in China during 2010 to 2021. There were significant differences in the value of various service functions of forest ecosystems in China. Among them, the largest was water conservation, followed by soil conservation, carbon sequestration and oxygen release, biodiversity conservation, air purification, forest recreation, forest product supply, forest protection, and nutrient retention. The service functions of mountain and urban forest ecosystems were highly heterogeneous. The main contributions of mountain forests were water conservation (36.94%), soil conservation (18.68%), biodiversity conservation (17.67%), and carbon sequestration and oxygen release (12.44%), while the main contributions of urban forests were carbon sequestration and oxygen release (29.37%), water conservation (22.49%), air purification (16.93%), and soil conservation (11.68%). Broadleaved evergreen forests had the highest values of ecosystem services, followed by deciduous broadleaved forests, mixed coniferous forests, and coniferous forests. In the past decade, although the evaluation method of forest ecosystem service value had been greatly enriched, there was still much room for improvement, especially in establishing indicator system. To provide a scientific foundation for the sustainable development of ecosystems and ecological environment construction, we must further optimize measurement methods and technical means, improve data acquisition capability, and strengthen the integrity and scientific nature of ecosystem service function assessment, which lays a foundation for the research on the realization path of ecosystem service value.





Review of the effects of atmospheric particulate matter on plants.

TANG Jingchao, HUANG Yu, SUN Baodi, SONG Zhiwen, XU Ailing

2024, 43(1):  254-263.  doi:10.13292/j.1000-4890.202401.009

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Atmospheric particulate matter (APM) is a general term for a complex mixture of solids and aerosols in the atmosphere, comprised of small droplets of liquid, dry solid fragments, and solid cores with liquid coatings. A large amount of APM can significantly affect climate, air visibility, and public health. Growing suitable plants can reduce the damage associated with particulate matter, although APM can affect plants to varying degrees through deposition or foliar uptake. Here, we systematically synthesize and review the causes and composition of APM and its effects on plant growth and development, physiology and biochemistry, resistance to disease and insects, productivity, and yield. Methods to reduce the harmful effects are discussed, and future research focusing on how APM affects plants is proposed. The effects of APM on plants are extensive, complex, and dependent on environmental conditions, the concentration and composition of particulate matter, plant species, and study scale. Avoiding or reducing the negative effects of APM can be achieved by predicting changes in the concentration of APM, providing adequate nutrition and hydration, washing the leaves, providing light, and choosing suitable plants. In the future, studies of landscapes and afforestation plants, large-scale vegetation physiology and ecology under the influence of APM, and the effects of various compounds and microbial particulate matter on plants need to be increased. Those researches can focus on plant ecophysiology, leaf nitrogen allocation, mesophyll cell conductivity, and plant genetics and breeding.





Influencing factors of soil organic carbon in mixed spruc-efir-broadleaved forest based on structural equation.

ZHAO Han, WANG Haiyan, HU Xingguo, LEI Xiangdong, DU Xue, ZOU Jiahe, CUI Xue

2024, 43(1):  264-272.  doi:10.13292/j.1000-4890.202401.011

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Vegetation, litter, topography, and soil attributes are driving factors of soil organic carbon (SOC) variations. However, few studies have examined those multiple driving factors simultaneously. The mixed spruce-fir-broad-leaved forest was selected  with 200 groups of data, including soil data of different soil layers, vegetation data, and data of different litter decomposition layers. Topographic data were obtained with remote sensing technology. To quantify the effects of each driving factor, correlation analysis and structural equation model were used to establish the relationship between observation variables and latent variables. According to the results of correlation analysis, five latent variables including vegetation, topography, litter return characteristics, soil properties, SOC content and SOC density (SOCD) were constructed, and 15 observation variables were selected. The test coefficients of the structural equation model basically passed with a multivariate square coefficient of 0.94, indicating that the equation construction was reasonable and that the convergence validity of the model met the standard. The four predicted latent variables had significant positive effects on SOC content and SOCD. The total effects were in order of soil attribute (0.938)> topography (0.383)> vegetation (0.131)> litter return characteristics (0.099). The contributions of interpretable partial effects were 60.5%, 24.7%, 8.4%, and 6.4%, respectively, with elevation, soil total phosphorus at depth of 20-40 cm, soil total nitrogen at 20-40 cm, soil total nitrogen at 0-20 cm and soil moisture content at 20-40 cm as the top five contributors to SOC content and SOCD. Topography (elevation and aspect) and vegetation (Shannon diversity index, number of species, canopy density) had indirect positive effects on SOC content and SOCD. Topography reached a very significant level through two paths: soil attribute and litter return characteristics (P<0.001), while vegetation only reached a significant level of 0.1 through soil attribute path. The relationship among driving factors was very complex. Vegetation affects SOC by affecting soil nitrogen, phosphorus, and soil properties of deep layers, litter has a positive effect on SOC through direct input, and topography indirectly affects SOC by affecting other soil properties through water and heat allocation. The structural equation established in this study expounds the action relationships of various driving factors in mixed spruce-fir-broadleaved forest, which provides a theoretical basis for SOC protection and soil nutrient management for natural forests.





Temporal and spatial variations and driving force analysis of NDVI in Henan Province based on Geodetector.

NIE Tong, DONG Guotao, JIANG Xiaohui, LEI Yuxin, GAO Siqi, HE Jiayin

2024, 43(1):  273-281.  doi:10.13292/j.1000-4890.202401.003

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As the main body of the terrestrial ecosystem, vegetation cover can effectively reflect the ecological and environmental change at global or regional scale. It is of great significance to analyze the spatiotemporal variations and driving factors of vegetation cover for regional ecosystem sustainable development. We used the normalized vegetation index (NDVI) to explore the temporal and spatial variations of vegetation in Henan Province from 2000 to 2019. The spatial differentiation characteristics and driving force of vegetation in Henan Province were analyzed by Geodetector model, and the future trend of vegetation was explained by Hurst index. The overall vegetation index in Henan Province showed a fluctuating upward trend from 2000 to 2019, with a growth rate of 0.016  10 a-1. The growth rate during 2009-2019 showed a decreasing trend. Soil type, land use type, GDP and population density greatly affected the spatial distribution of NDVI. The interaction of any two factors exceeded the influence of a single factor, and the interaction of natural and human factors had a significant impact on the spatial distribution of NDVI. Based on the analysis of Hurst index, we found that the future NDVI changes in Henan Province showed anti sustainability characteristics, the area with Hurst index <0.5 accounted for 58.3% of the vegetation coverage in the whole study area, and the whole study area mainly would show a decreasing trend in the future.





Driving factors and prediction model of forest fire in Guizhou Province.

ZHANG Yunlin, TIAN Lingling, DING Bo, ZHANG Yanwei, LIU Xun, WU Yan

2024, 43(1):  282-289.  doi:10.13292/j.1000-4890.202401.017

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The forest area of southwest China has complex fire sources and human interference, most of which are karst landform and in the ecotone of agriculture and forestry, leading to the most serious forest fire disaster area in China. The area has high mountains and steep slopes, making it extremely difficult to extinguish a fire once it occurs. It is of great significance to analyze the driving factors of forest fire in this region and to carry out fire risk zoning for rational forest fire management. Based on the forest fire point data, geospatial data, meteorological data, vegetation data and human activity data from 2011 to 2020, the spatiotemporal pattern of forest fire distribution in Guizhou in the past decade was analyzed, and the driving factors and probability prediction model of forest fire occurrence were obtained. The forest fire occurrence probability and forest fire risk zoning map of Guizhou in different seasons were analyzed. The results showed that in the past 10 years, the number of fire points in Guizhou showed a downward trend year by year. Fire points were mainly concentrated from January to March, accounting for 61% of the total number of fire points in a whole year. Distance from residential areas, distance from railways, population density, monthly average air temperature, monthly average relative humidity and monthly cumulative rainfall had significant effects on the probability of forest fire in Guizhou. A Logistic regression model was established. The prediction accuracy of the model was 81.9%, and the area under the curve was 0.904. The occurrence probability of forest fire in spring was higher than that in other seasons. The high-risk areas of forest fires in spring, autumn, and winter was mainly concentrated in western Guizhou, while the high-risk areas in summer were mainly distributed in eastern Guizhou. Research on the driving factors of forest fire occurrence and fire risk zoning maps based on the seasons is of great significance to the scientific management of forest fires in Guizhou. Forest fires in western Guizhou mainly occur in remote areas with a high probability of fire occurrence. Observation towers and video surveillance equipment should be added, patrol should be strengthened, and monitoring scope and timeliness should be improved. Fire prevention publicity and the control of human activities should be strengthened in eastern Guizhou in summer to reduce the probability of fire occurrence.





Dynamic evaluation of ecological environment quality in the Yellow River source region based on GEE platform.

ZHAO Kaixin, LI Xuemei, WANG Guigang, SUN Xuwei

2024, 43(1):  290-298.  doi:10.13292/j.1000-4890.202401.022

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The source region of the Yellow River is one of the ecologically fragile regions in China. In recent years, its ecological environment problems have attracted much attention. Based on the Google Earth Engine (GEE) platform and combined with the remote sensing images of Landsat in the source region from 1990 to 2021, we synthesized six indicators (heat, dryness, air quality, greenness, humidity, and leaf area index) to construct a remote sensing ecological index, which were used to evaluate the dynamics of ecological environment quality in this region. The heat, dryness, and air quality had a negative feedback effect on the ecological environment quality in the source region, while greenness, humidity, and leaf area index had a positive effect, of which greenness was the most critical influencing factor. The area with ecological environment quality improvement accounted for 74.51% of total area of the source region, with an overall spatial pattern of “southern superiority and northern inferiority”. The overall quality of the ecological environment improved during 1990-2021. Over the past 30 years, the ecological environment quality of 89.75% of total area of the source region experienced relatively small changes and maintained good stability. Hurst index analysis showed that the ecological environment quality of 66.36% of total area of the source region had medium and strong sustainability, and that the ecological environment quality in the source region will be better in the future.





Assessment of habitat suitability in autumn for wild alpine musk deer in Xinglongshan National Nature Reserve with MaxEnt model.

LIN Hongdong, ZHENG Qize, SHEN Liquan, WANG Gong, LIU Rui, ZHANG Xueyan, QI Jun, ZHANG Aiping, MENG Xiuxiang

2024, 43(1):  299-304.  doi:10.13292/j.1000-4890.202401.021

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Habitat suitability assessment is of great significance for wildlife conservation and nature reserve management. To understand the habitat condition of wild alpine musk deer (Moschus chrysogaster) in Xinglongshan National Nature Reserve, infrared cameras were utilized to collect the distribution data of wild alpine musk deer from September to November in 2021. With the topography, NDVI, distance from rivers and distance from roads as environmental variables, we evaluated the habitat suitability of wild alpine musk deer in autumn by MaxEnt model. The results showed that NDVI, distance from roads, distance from rivers, and elevation were the main factors influencing the suitability of autumn habitat of wild alpine musk deer in the reserve, with the contributions of 33.20%, 22.70%, 16.70% and 14.60%, respectively. The area of potential autumn suitability of wild alpine musk deer in the reserve was 75.22 km², accounting for 26.13% of the reserve area. The highly suitable area was mainly distributed in the northwestern and southeastern areas of the reserve, accounting for 3.26% of the reserve area. This study quantified the distribution of suitable habitats in autumn and key environmental impact factors of wild alpine musk deer in the reserve, which can benefit the conservation and habitat management of the wild alpine musk deer.