Table of Content

10 November 2024, Volume 43 Issue 11

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Dynamic analysis of interspecific association in a valley monsoonal rainforest community in northern tropical region.

HE Qiaoping, LUO Yinghua, JIANG Dongdong, LING Yaming

2024, 43(11):  3233-3239.  doi:10.13292/j.1000-4890.202411.014

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The study of changes in inter-species relationships would help reveal plant community succession and provide a basis for the mechanistic understanding of the ecological stability of communities and biodiversity maintenance. In 2015, a 1 hm² forest monitoring plot was established in the core distribution area of Hopea chinensis, a key species in the northern tropical valley monsoon rainforest of Shiwandashan, Guangxi. We assessed the changes of interspecific relationships of 22 major species in the community by comparing the data in 2015 and a reassessment in 2020, using the variance ratio (VR), Pearson correlation coefficient and Spearman rank correlation analysis. Results showed that: (1) The VR value of this community was 1.09 in 2015 and 0.98 in 2020. There was a significant VR deviation from 1 (with ω=108.75 and 97.78 in 2015 and 2020, respectively), both falling within the interval of \[77.93, 124.34\]. The overall interspecific associations were not significant. (2) Pearson correlation coefficient analysis showed that there were 28 species pairs with significant positive associations and 14 species pairs with significant negative associations in 2015. There were 35 species pairs with significant positive associations and 18 species pairs with significant negative associations in 2020. Spearman rank correlation analysis showed that there were 26 species pairs with significant positive associations and 19 species pairs with significant negative associations in 2015. The species pairs with significant positive associations in 2020 increased to 31 while those with negative associations remained similar (18 species pairs). (3) The correlation between Hopea chinensis and other species became stronger, with no change in significant positive association species pairs, and decreases in significant negative association species pairs. The ecological dominance of Hopea chinensis increased. In conclusion, the significant positive associations among species were enhanced with time. The associations among major species were complicated, but the changes within the 5-year period showed stability in the positive associations among major species, indicating that the community was in a positive stage of dynamic succession.





Plant community composition and structure of the nascent wetlands of the Yellow River Estuary.

ZOU Yuhan, LI Xue, ZHANG Xin, LING Yue, YU Junbao, LI Yunzhao, WANG Xuehong, YANG Jisong, GUAN Bo, MA Yuanqing, SONG Xiukai

2024, 43(11):  3240-3245.  doi:10.13292/j.1000-4890.202411.030

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The species identity, composition, distribution, and evolution of plant community can reflect the development direction of wetland ecosystem, and affect the proper functioning of main ecological functions. To investigate plant community structure, a transect with a width of about 500 m perpendicular to the community transition zone was established in the Yellow River Estuary in 2021. The results showed that there were 15 species of higher plants which belonged to 11 families and 15 genera. The plant communities with strip distribution from the river to the sea could be divided into seven types. Spartina alterniflora dominated the vegetation. Species composition of the vegetation was relatively simple, mainly composed of herbaceous species. The Shannon diversity index increased first and then decreased along the river to the sea direction. In the past 10 years, plant community of wetlands in the Yellow River Estuary had shown dramatic changes. The species number of plant community declined, the top two species in terms of importance value changed considerably, and the established species of some communities gradually disappeared or were replaced by new species. This study highlights the rapid evolution of plant community, providing scientific reference for biodiversity conservation and ecological management of newborn wetlands in the Yellow River Estuary.





Dynamics of understory plant diversity and biomass of Pinus sylvestris var. mongolica plantations with different ages in Mu Us Sandy Land.

HU Ercha, WANG Zheng, LI Zihao, YANG Haifeng, LI Zhuofan, WANG Xiaojiang, GAO Runhong

2024, 43(11):  3246-3254.  doi:10.13292/j.1000-4890.202411.018

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Understanding the dynamics of understory plant diversity and biomass in plantations is of great significance for assessing the effectiveness of sandy vegetation restoration and plantation management. We analyzed the characteristics of understory communities in Pinus sylvestris var. mongolica plantations with different stand ages (Ⅰ: ≤10 a, Ⅱ: 10 a<age≤15 a, Ⅲ: 15 a<age≤20 a, Ⅳ: age>20 a) in Mu Us Sandy Land. The impact of stand factors on understory plant communities was analyzed using structural equation modeling path analysis. A total of 57 species from 47 genera and 20 families were recorded, including 3 shrub species. Asteraceae, Gramineae, Leguminosae and Chenopodiaceae dominated herbaceous layer, accounting for 50% of the total herbaceous species. With increasing stand age, the number of families, genera and species of herbaceous layer decreased first and then increased. With increasing stand age, the perennial herbaceous plants increased, the annual and biennial plants decreased relatively, the xerophytes decreased, and the mesophytes increased. The Shannon diversity index, Simpson dominance index and Margalef richness index of herbaceous layer decreased first and then increased with increasing stand age, and the Pielou evenness index increased with increasing stand age, but there was no significant difference among different stand age classes (P>0.05). There was a negative relationship between tree layer coverage and shrub layer coverage and biomass, and a positive relationship between tree layer coverage, shrub layer coverage and understory herb layer coverage, aboveground biomass, species richness and Shannon diversity index. There was a negative correlation between aboveground biomass of shrub layer and herb coverage, aboveground biomass, species richness and Shannon diversity index. In summary, the vegetation restoration model of Pinus sylvestris var. mongolica plantation in Mu Us Sandy Land is conducive to the restoration of understory herbaceous plants. Trees and shrubs should be rationally allocated in the future restoration of sandy vegetation to improve species diversity and community stability.





Alleviation effect of melatonin on degressive photosynthetic rate in Salix viminalis exposed to cadmium.

YIN Jiahui, LI Xia, ZOU Junzhu, JU Guansheng, NING Wei, LI Ao, WANG Yuancheng, SUN Zhenyuan

2024, 43(11):  3255-3265.  doi:10.13292/j.1000-4890.202411.034

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Salix viminalis has an outstanding capacity to accumulate cadmium (Cd), but with poor tolerance to high concentrations of Cd. Investigating the regulation function of melatonin (MT) on photosynthetic rate of S. viminalis exposed to high concentrations of Cd would help reveal the alleviation effect of MT on woody plants exposed to Cd and provide supporting measures for phytoremediation of heavy metals. Cutting seedlings of clonal S. viminalis were used as experimental material. Three treatments were set as blank (BT), Cd stress (CT), and foliar spraying MT followed by Cd stress (MCT). We examined the regulatory modes of MT on photosynthetic gas exchange parameters, chlorophyll fluorescence parameters under dynamic light, and the content of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in S. viminalis under Cd stress. The chlorophyll a (Chla) and Rubisco contents of S. viminalis exposed to Cd were decreased by 20% and 21% on the 7th day after treatment, respectively. The chlorophyll b (Chlb), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), net photosynthetic rate (P_n) of S. viminalis exposed to Cd were decreased by 32%, 35%, 23%, 21% on the 14th day after treatment. Under the treatment of spraying 50 μmol·L^-1 MT, Chl a, Chlb G_s, C_i, Rubisco content were increased by 30%, 28%, 47%, 35%, 25% respectively. P_n and photosystem Ⅱ (PSⅡ) maximum photochemical efficiency (F_v/F_m) of S. viminalis exposed to Cd stress were decreased by 36% and 16% on the 21st day after treatment. After MT spraying, P_n and F_v/F_m were increased by 39% and 13%, respectively. Photoinhibition of S. viminalis exposed to Cd was aggravated, while spraying MT alleviated its photoinhibition. Under Cd stress, MT promoted photosynthetic gas exchange of S. viminalis by increasing stomatal conductance, promoted light harvesting by maintaining chlorophyll concentration, improved photosynthetic capacity by enhancing light energy conversion efficiency and photosynthetic electron transfer rate, and promoted CO₂ assimilation by increasing Rubisco content. Moreover, MT promoted growth of S. viminalis exposed to Cd stress by increasing photosynthetic intensity.





Isoprenoid release from Castanopsis carlesii under acute O₃ stress and its effect on ozone formation potential.

LIAO Lulu, ZHANG Geye, ZHANG Junchuan, CHEN Hongmei, LI Qiang, YI Zhigang

2024, 43(11):  3266-3272.  doi:10.13292/j.1000-4890.202411.026

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Isoprenoids, mainly including isoprene and monoterpenes, are among the most important biogenic volatile organic compounds (BVOCs) from plants and play an important role in atmospheric environments. In this study, Castanopsis carlesii was treated with O₃-CK (ambient O₃ concentration), O₃-250 (O₃ concentration 250 ppb) and O₃-500 (O₃ concentration 500 ppb) for acute O₃ stress of 8 h and 16 h. We investigated the effects of acute O₃ stress on BVOc emissions from C. carlesii and the associated physiological parameters, as well as the contribution of BVOC emissions to ozone formation potential (OFP). The results showed that after 8 h acute O₃ stress, the release rate of monoterpene was higher under the treatment with O₃ stress than that of the control group, and reached a peak at O₃-250 treatment (52.72±35.72 pmol·m^-2·s^-1), while the release rate of isoprene was lower than that of the control group. At the O₃-250 treatment, it decreased to the lowest (0.70±0.27 pmol·m^-2·s^-1). The contents of γ-terpinene and limonene increased significantly, and α-pinene and limonene contributed more to OFP. After 16 h acute O₃ stress, the release rate of monoterpene under O₃ stress was higher than that of the control group, but the release rate of isoprene did not change. The content of 3-carene increased significantly, and α-pinene, limonene, 3-carene contributed more to OFP. Monoterpene synthetase and isopentadiene synthetase decreased significantly under O₃ stress. Photosynthetic rate of C. carlesii and release rate of monoterpene and isopentadiene decreased with increasing stress time. Acute O₃ stress promoted monoterpene emission and inhibited isoprene emission, with a positive effect on OFP as a whole. This study can provide theoretical basis for future studies on the response of BVOC release to O₃ under the trend of near-surface O₃ concentration increase and the mechanism of BVOCs on O₃ formation.





Latitudinal pattern and causes of leaf vein traits of Bauhinia brachycarpa in arid valley.

WU Yiling, LI Fanglan, BAO Weikai, HU Hui, YANG Tinghui, LI Xiaojuan

2024, 43(11):  3275-3282. 

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The aim of this study was to clarify the biogeographic patterns of leaf functional traits of Bauhinia brachycarpa, mainly vein density, and the influencing mechanisms. We investigated the variation characteristics of vein density in different grades and leaf morphology of Bauhinia brachycarpa, a dominant shrub along a latitude gradient (23°16′N-31°30′N, 101°28′E-103°25′E) in the arid valley of southwest China, and analyzed the relationship among leaf traits. The results showed that vein density and leaf surface area decreased with increasing latitude, and that main vein density was negatively correlated with specific leaf area. The total vein density and minor vein density were independent of leaf morphological traits, such as leaf surface area, while the main vein diameter was positively correlated with leaf morphological traits and specific leaf area. The latitudinal variation of leaf vein traits was affected by the average precipitation in dry season, soil cation exchange capacity, altitude, and annual average temperature. Our results help reveal the ecological adaptation mechanism of xerophytes in arid valleys.





Estimation and prediction of carbon stock of semiarid Pinus sylvestris var. mongolica forest employing multiple allometric growth equations.

LIN Jing, LIU Yu, SU Changhong

2024, 43(11):  3283-3290.  doi:10.13292/j.1000-4890.202411.013

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Afforestation for carbon sequestration is an effective strategy to combat global warming. Pinus sylvestris var. mongolica is one of the widely-used afforestation tree species in the semiarid region of northern China. It covers the vast semiarid area from eastern Inner Mongolia to the Loess Plateau. The assessment and prediction of carbon storage of P. sylvestris var. mongolica forests is helpful to understanding the effect of afforestation on carbon sink in semiarid regions of China. Seven allometric growth equations developed for environmental settings in  semiarid Inner Mongolia were collected. Then the vegetation carbon storage of P. sylvestris var. mongolica forests in 2022 was evaluated by combining the surveyed tree height, diameter at breast height and age of single trees. The  biomass and carbon storage of P. sylvestris var. mongolica forests in 2030, 2040, 2050 and 2060 were predicted. The results showed that height and diameter at breast height of P. sylvestris var. mongolica increased with an overall growth trend of “slow-fast-slow”, and the maximum values were predicted to reach at 18 and 16 years old, respectively. The trend of biomass of P. sylvestris var. mongolica forest was similar to that of diameter at breast height and tree height. The carbon storage of P. sylvestris var. mongolica forests in this area tended to be stable at the age of 20 years old. Carbon density of P. sylvestris var. mongolica forests was 0.23-0.87 kg·m^-2 in 2022, and will be 1.2-3.4 kg·m^-2 in 2030, with an average of 2.0 kg·m^-2. In 2040, carbon density of P. sylvestris var. mongolica forests will be 1.3-3.7 kg·m^-2, with an annual increment of 0.2-0.3 kg·m^-2 in ten years. In 2050, carbon density of forests will be 1.4-3.7 kg·m^-2, with an annual growth rate of 0.08%-0.4%. In 2060, carbon density of P. sylvestris var. mongolica forests will still be 1.4-3.7 kg·m^-2. However, there is a substantial difference in carbon storage calculated based on the seven allometric growth equations, indicating great uncertainty in estimation of forest carbon stock and the critical needs of multi-equation comparison.





Effects of nitrogen application on growth, yield, and grain quality of spring maize under drought conditions.

LI Mingyu, CHEN Nina, MI Na, ZHANG Shujie, CHEN Mingxin, SHAN Nan, ZHANG Wei

2024, 43(11):  3291-3299.  doi:10.13292/j.1000-4890.202411.010

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To clarify the effects of nitrogen application on the growth, yield, and grain quality of spring maize under drought conditions, an experiment was conducted under moderate drought stress (relative moisture 45%±5%) and four nitrogen addition levels of 0, 120, 240 and 270 kg·hm^-2 at the two key developmental stages (jointing and tasseling) of spring maize (cultivar Danyu 405). We analyzed the responses of spring maize growth, yield component and grain quality to the interaction of drought and nitrogen application. The results showed that compared with the control treatment of suitable water and no nitrogen application, nitrogen application under drought during the jointing stage increased plant height, ear length, bald tip ratio, amino acids content, and crude protein content of spring maize, while decreased leaf area index, biomass, ear diameter, 100-kernel weight, theoretical yield, grain water content, fat content, and starch content of spring maize. The effects of nitrogen application under drought during the tasseling stage were similar to that during the jointing stage, but with negative impact on ear length. Compared with the nitrogen application under drought during the jointing stage, leaf area index, bald tip ratio, grain water content, fat, starch, amino acids, and crude protein content were increased by 18.5%, 116.7%, 4.9%, 8.6%, 1.4%, 8.8%, and 28.0% during the tasseling stage, respectively, while plant height, biomass, ear length, ear diameter, 100-kernel weight, and theoretical yield were decreased by 2.9%, 2.4%, 20.1%, 7.7%, 4.3%, and 40.8%, respectively. With increasing nitrogen application levels under drought, plant height, biomass, ear length, bald tip ratio, grain water content, and starch content increased, while leaf area index, ear diameter, 100-kernel weight, theoretical yield, fat, amino acids, and crude protein content decreased. The yield components of spring maize were negatively correlated with grain quality. Nitrogen application had an inhibitory effect on maize yield under drought, but improved grain quality to a certain extent. Our results provide scientific basis for the production management and stress control of spring maize in Liaoning Province.





Impacts of ultraviolet radiation on litter decomposition rate and alterations in chemical constituents in an extremely arid region.

LI Meiqi, LI Chengdao, LI Xiangyi, WANG Peng

2024, 43(11):  3300-3308.  doi:10.13292/j.1000-4890.202411.012

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Litters are exposed to intense sunlight for an extended period due to limited precipitation and prolonged sunshine duration in extremely arid regions. The influence of solar radiation on litter mass loss is predominant in extremely arid ecosystems. The litterbag method was employed to investigate litter decomposition of three dominant plant species under natural light exposure and shading from ultraviolet radiation in Cele Oasis desert area, the  southern edge of the Taklamakan Desert. The results showed that decomposition rate of all the three types of litter was significantly higher under natural light than under UV shading. The mass remaining rate of litter at the end of decomposition under UV shading was 79.97%, 77.79%, and 82.55% higher than that under natural light for Karelinia caspica, Alhagi sparsifolia, and Populus euphratica, respectively. The Pearson correlation coefficients between organic matter loss rate and mass loss rate under natural light were 0.975, 0.982, and 0.991 for Karelinia caspica, Alhagi sparsifolia, and Populus euphratica respectively, and 0.786, 0.906, and 0.800 correspondingly under UV shading, with a stronger association under natural light compared to UV shading. Additionally, UV shading significantly mitigated the loss of soluble salt, C, and N as well as altered the C∶N ratio in all three types of litter. Findings from this study contribute to enhance our understanding of the decomposition mechanism of litter in extremely arid regions, providing a fundamental basis for future investigations on litter decomposition in arid ecosystems.





The effect of litter input changes on CH₄ uptake in forest soils.

ZHENG Xiaping, WU Fuzhong, WU Qiuxia, ZHU Jingjing, NI Xiangyin

2024, 43(11):  3309-3316.  doi:10.13292/j.1000-4890.202411.016

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Methane (CH₄) is the second important anthropogenic greenhouse gas after carbon dioxide (CO₂). Forest soils are a sink for atmospheric CH₄ and play an important role in modulating global CH₄ budget. Litter is important carbon and nutrient sources for forest soils. Litter decomposition could increase soil carbon and nutrient concentrations and reduce oxygen concentration beneath the soil surface as well as the oxidation and diffusion of soil CH₄. However, it remains unclear whether litter input changes CH₄ uptake in forest soils. In this study, a microcosm experiment was conducted in a subtropical forest, and soil CH₄ flux under the conditions with and without litter input was monitored monthly by chambers in a Chinese fir (Cunninghamia lanceolata) plantation over one year. We found that litter removal significantly increased soil CH₄ uptake in Chinese fir plantation. We further analyzed the changes in soil CH₄ flux after litter removal (leaf and root) and double litter input at six forest sites in other climatic zones. We found that litter removal significantly increased soil CH₄ uptake in broadleaved forests by 16.5%. On the contrary, double litter input decreased soil CH₄ uptake by 11.1% and 20.0% in broadleaved and coniferous forests, respectively, suggesting that the function of CH₄ sink in forest soils decreased with additional litter input. Our results suggest that litter input is an important factor affecting CH₄ flux uptake in forest soils, and that litter layers may reduce atmospheric CH₄ uptake by forest soils through reducing the oxygen concentration beneath soil surface.





The evolution characteristics of soil pH in Guangxi in 1984-2019.

LI Jinmei, HUANG Mei, KANG Jili, LIU Wenqi, HOU Xianda, WANG Shuojin, JIA Shugang, LIU Shutian, HOU Yanlin

2024, 43(11):  3317-3323.  doi:10.13292/j.1000-4890.202411.008

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Soil acidification reduces productivity. To explore the changes of soil pH in Guangxi between 1984 and 2019, geostatistics, dynamic degree and distribution index were used to analyze the sampling point data of the project and the long-term observation data from 2010 to 2019. The results showed that soil pH decreased from 1984 to 2019, and its distribution changed from uneven to relatively continuous. The area proportion of soil pH grade was as follows: grade 2 > grade 3 > grade 4 > grade 1 > grade 5 > grade 6. The soil pH was mainly composed of grade 2 and grade 3. The area of grade 2 and grade 3 accounted for 76.71% of total area in 1984 and 84.84% in 2019. In terms of change rate, grade 1 (-1.99%) and grade 5 (0.44%) showed the most rapid change. The dynamic degree was following an order of grade 1 > grade 6 > grade 5 > grade 2 > grade 3 > grade 4. The pH distribution index curve of grade 6 fluctuated significantly across different elevation regions.





The relationships between carbon, nitrogen, phosphorus in plants, soil nutrients and slope in different forest types in the Helan Mountains.

LIU Huili, MA Ruoshi, ZHAO Xiaoyu, WANG Ziyin, LIU Bingru

2024, 43(11):  3324-3332.  doi:10.13292/j.1000-4890.202411.031

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We analyzed C, N, and P concentrations in roots, stems and leaves of different plant species, as well as soil nutrients in different slope aspects in Picea crassifolia forest, Prunus mongolica shrublands, and Ulmus pumila shrublands distributed in same altitude on the shady and sunny slopes of Helan Mountains. The key factors affecting plant nutrient contents were identified, and the relationships between C, N, and P of plants and soil nutrients as well as the slope aspects of different forest types were examined. There were significant differences in soil organic C, total N, and total P contents in Ulmus pumila shrublands and Prunus mongolica shrublands, and soil organic C (37.69 g·kg^-1) and total P (0.65 g·kg^-1) contents were the highest in Picea crassifolia forest on the shady slope. On the same slope aspects, soil organic C, total N, and alkaline hydrolyzable N (AN) of Picea crassifolia forest were higher than those of other two forest types. There were no significant differences in soil C/N and C/P among different forest types and slope aspects, and the N/P was lower than the average level of soils in China, indicating that there was a serious shortage of soil N supply. Leaf C content varied significantly among different forest types, with the highest value of 483.92 g·kg^-1 in Picea crassifolia forest on a shady slope. The pattern of C, N, and P contents in roots were consistent with those in leaves. There was no significant correlation between leaf C content and soil C content, a significant negative correlation between leaf N and soil N, and a significant positive correlation between leaf P and soil available P. Nutrients in leaves and roots are sensitive to slope aspects, but the processes of C assimilation and N and P fixation were not entirely synchronized with soils. Soil N/P and AN are the key factors driving the changes of nutrient contents of roots, stems, and leaves.





Soil acid buffering capacity of subtropical arbuscular and ectomycorrhizal forests  and its main influencing factors.

LI Jing, XIA Shangguang, SHI Xiaoyun, SUN Qingye, ZHAO Qiong

2024, 43(11):  3333-3340.  doi:10.13292/j.1000-4890.202411.022

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Soil acid buffering capacity plays an important role in preventing soil acidification induced by fertilization and atmospheric nitrogen deposition, and thus is critical for maintaining soil functioning. Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) plants differ greatly in functional traits, but how the differences of their impacts on soil acid buffering capacity are still poorly understood. In this study, forests with dominant tree species associated with AM and ECM fungi in subtropical China were selected, aiming to investigate soil acid buffering capacity and the relevant physicochemical properties of forest soils. The results showed that AM-dominated forest soils had significantly higher soil acid buffering capacity than ECM-dominated forest soils. In comparison, pH, exchangeable base cations, cation exchange capacity, exchangeable K⁺, Na⁺, Ca²⁺, organic matter and nitrate concentrations were significantly higher in AM-dominated forest soils, but ammonium concentrations were lower than ECM-dominated forest soils (P<0.01). Soil acid buffering capacity was positively correlated with pH, soil organic matter, exchangeable calcium, cation exchange capacity and base saturation (P<0.01), the exchangeable base cations and exchangeable magnesium (P<0.05), while it was significantly negatively correlated with the exchangeable acid content (P<0.01). In addition, 47.4% of the variation in soil acid buffer capacity could be explained by the contents of exchangeable calcium and organic matters. Therefore, AM tree species can improve soil acid buffering ability by promoting accumulation of organic matters and exchangeable base cations (mainly Ca²⁺) in soils. Moreover, AM-dominated forests could prevent soil acidification better than ECMdominated forests in subtropical regions when exposed to chronic atmospheric nitrogen deposition.





Spatial-temporal pattern of soil water content and its response to precipitation in a tropical seasonal rainforest in Xishuangbanna.

LI Jiayuan, LIU Lulu, YANG Bin, LUO Yan, BAI Linzhong, LU Huazheng, Song Liang

2024, 43(11):  3341-3349.  doi:10.13292/j.1000-4890.202411.011

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To understand the spatial-temporal dynamics of soil water content under precipitation fluctuations especially extreme precipitations in tropical seasonal rainforest, we analyzed 15 years (2006-2020) data of soil water content at different depths (up to 110 cm) and precipitations in a tropical seasonal rainforest of Xishuangbanna. We found that the annual average soil water content remained stable over the 15 years with a relatively low interannual coefficient of variation (CV). But we detected a pattern of obvious seasonal dynamic because CV of the rainy season was significantly higher than that of the dry season. In addition, soil water content generally followed a “C” shape pattern along the soil vertical profile. Specifically, soil water contents in both shallow and deep depths were significantly higher than that in middle depths. In recent years, extreme precipitation events occurred frequently in Xishuangbanna, with increasing precipitation fluctuation. However, changes of soil water content did not follow the trend of precipitation but rather remained relatively stable through the spatio-temporal dynamic balance of soil water loss and recharge across seasons and soil depths. Our results highlight that the tropical seasonal rainforest in Xishuangbanna could maintain soil water content under fluctuation of precipitations, even extreme ones. Xishuangbanna tropical seasonal rainforest shows a strong ability to regulate soil water content and therefore to conserve water resources. This study provides empirical support for understanding the important ecological functions of tropical seasonal rainforests.





Early effects of different tree species mixing on aggregate organic carbon fractions.

YE Yuqian, WANG Hui, LUAN Junwei, MA Jinhao, MING Angang, LIU Shirong

2024, 43(11):  3350-3356.  doi:10.13292/j.1000-4890.202411.007

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Plantations play an important role in carbon sequestration, with different effects of tree species mixture on soil organic carbon. In this study, we examined the effects of three typical twospecies mixed plantations, Pinus massoniana + Castanopsis hystrix (PC), Pinus massoniana + Erythrophleum fordii (PE), and Erythrophleum fordii + Mytilaria laosensis (EL), on aggregate organic carbon and its fractions in the south subtropical area, as well as the driving factors of organic carbon at different aggregate levels. The results showed that EL promoted the formation of large macroaggregates. The highest value of mean weight diameter of aggregates was observed in EL (1.71 mm), followed by PE (1.39 mm) and PC (1.26 mm). The macroaggregate organic carbon content (>2 mm) was 1.8 and 1.4 times higher in EL than those of PC and PE, respectively. EL promoted the accumulation of particulate organic carbon within aggregates, which was mainly originated from coarse and fine organic particulate carbon within large macroaggregates, and coarse particulate organic carbon within small macroaggregates. EL promoted the stability of aggregates and the accumulation of aggregate organic carbon by increasing inputs of leaf litter and roots.





Vertical distribution of soil mercury and its methylation drivers in different vegetation zones of Changbai Mountain.

SUN Fan, ZHENG Dongmei, JIANG Shan, ZHANG Zhongsheng, WU Haitao, GUAN Qiang

2024, 43(11):  3357-3364.  doi:10.13292/j.1000-4890.202411.003

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It is of great significance for understanding the mercury (Hg) biogeochemical cycle to reveal the distribution characteristics and methylation mechanism of Hg in alpine ecosystems. In this study, we analyzed the distribution characteristics of Hg and methylmercury (MeHg) in the surface soil and litter of four vegetation zones on the northern slopes of the Changbai Mountain, and elucidated the role of environmental factors on Hg methylation. The results showed that the mean concentration of total Hg in soil was 72.9±32.3 ng·g^-1. The mean concentration of MeHg was 4.5±1.7 ng·g^-1, accounting for 7.79% of total soil Hg. The mean concentration of total Hg in litter was 155.5±34.4 ng·g^-1. SUVA₂₅₄, SUVA₂₆₀ and Mn in soil had negative effects on MeHg, while total carbon concentration had a positive effect on MeHg. There were obvious altitudinal distribution patterns of Hg and MeHg in soils of Changbai Mountain, with total Hg concentrations in different vegetation zones showing the order of alpine tundra zone > Betula ermanii forest zone > coniferous forest zone > coniferous and broadleaf forest zone, and MeHg concentrations showing the order of Betula ermanii forest zone > alpine tundra zone > coniferous forest zone > coniferous and broadleaf forest zone. MeHg concentration in soil was mainly influenced by altitude, SUVA₂₅₄, Mn and total Hg concentration, and was not related to total Hg concentration in litter.





The response of Salix matsudana Koidz. to single and coexistence system of nano-titanium dioxide and cadmium in soil.

WANG Yuerui, WANG Siyuan, ZHU Jun, ZHANG Xuanyu, CHEN Chunyuan, WANG Ruoxi, SONG Jiayi, ZOU Jinhua

2024, 43(11):  3365-3375.  doi:10.13292/j.1000-4890.202411.032

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Cadmium (Cd) is a kind of highly toxic heavy metal element which exists in nature for long time. Titanium dioxide nanomaterials (TiO₂ NPs) are a new type of nanomaterial widely used in various fields due to special surface properties, which inevitably enter the environment to coexist with Cd. The coexistence of Cd and TiO₂ NPs in soil would affect plant growth. In this study, we conducted morphological, cytological, subcellular observations and physiological and biochemical measurements on Salix matsudana Koidz. seedlings under the single or combined treatments of Cd and TiO₂ NPs in soils. The results showed that Cd and TiO₂ NPs alone inhibited the growth and development of S. matsudana, produced peroxide damage, reduced photosynthesis, and altered the distribution of Cd in tissues and subcells. Low concentrations of TiO₂ NPs in coexistence with Cd reduced the biotoxicity of Cd by changing the subcellular distribution of Cd, and alleviated the peroxidative damage and photosynthesis inhibition of Cd on S. matsudana. In contrast, high concentrations of TiO₂ NPs coexisted with Cd increased the distribution of Cd in organelle fractions, aggravated Cd toxicity to plants, and inhibited plant growth. Therefore, the appropriate concentration of TiO₂ NPs can alleviate the toxic effect of environmental Cd stress on S. matsudana and improve its phytoremediation efficiency. Our findings provide theoretical basis for the application of S. matsudana in phytoremediation.





Differences of soil microbial community structure and co-occurrence network in rice field with light and moderate levels of cadmium pollution.

ZHANG Beibei, WANG Xingqi, LI Zhuoqing, DU Huihui, LIU Xiaoli, TIE Boqing, LEI Ming

2024, 43(11):  3376-3382.  doi:10.13292/j.1000-4890.202411.001

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To elucidate the impacts of cadmium pollution on soil microorganisms, soil samples were collected from lightly and moderately cadmium polluted farmlands in Zhuzhou of Hunan Province. This study analyzed the variations of bacteria, fungi and archaea communities, assessed the effects of soil physicochemical properties on soil microbial community structure, and explored the variation of soil microbial networks by network analysis. The results showed  cadmium pollution significantly altered the alpha diversity indices of bacteria and archaea, but did not significantly affect the alpha diversity indices of fungi. There were significant differences in microbial community structure between lightly and moderately cadmium polluted farmlands. Soil pH, total cadmium (Cd_T), available cadmium (Cd_A), available phosphorus (AP), and microbial biomass carbon (MBC) significantly affected bacteria and archaea, while fungi were mainly affected by pH, Cd_T, Cd_A, nitrate nitrogen (NO₃^-), and ammonium nitrogen (NH₄⁺). Co-occurrence network analysis revealed that moderate cadmium pollution reduced the number of connections, average node degree, and graph density in the microbial co-occurrence network, indicating that increased cadmium pollution affects interactions between microbes and reduces the complexity of microbial networks.





Effect of organic fertilizer replacing chemical fertilizer on wheat growth and soil nutrients.

ZHANG Dongxu, HU Danzhu, YAN Jinlong, FENG Liyun, WU Zhiyuan, LI Yanhua, YAN Haili, CHENG Yongming, ZHANG Junling

2024, 43(11):  3383-3393.  doi:10.13292/j.1000-4890.202411.004

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To explore the effects of different types and proportions of organic fertilizers instead of chemical ones on wheat yield, photosynthetic rate and soil nutrient utilization under the same contents of nitrogen, phosphorus and potassium, a field positioning experiment was conducted at the wheat experiment base of the Millet Research Institute of Shanxi Agricultural University from September 2020 to June 2022. The experiment adopted a split-plot design. The main plot was organic fertilizer type, including bio-organic fertilizer (A1) and decomposed sheep manure (A2). In the subplots, five treatments (CK, B25, B50, B75, B100) were used to replace chemical fertilizers with organic ones. The results showed that replacing chemical fertilizer by 25% and 50% of bio-organic fertilizer and decomposed sheep manure could significantly improve net photosynthetic rate, chlorophyll relative content, normalized difference vegetation index, and nutrient uptake and utilization rate of flag leaves in the middle and late stages of wheat filling compared with sole application of chemical fertilizer. The bio-organic fertilizer and decomposed sheep manure (B25, B50) instead of chemical fertilizer promoted the synergic development of panicle number and kernel number per spike per unit area and 1000-grain weight, and significantly increased yield by 5.5%-23.1%. The average yield of bioorganic fertilizer treatment was 3.4% higher than that of decomposed sheep manure. The contents of alkali-hydrolyzed nitrogen, available phosphorus and organic matter in 0-20 cm soil layer treated with organic fertilizer replacing chemical fertilizer were significantly increased by 11.3%-50.9%, and the available potassium (B75, B100) was also significantly increased by 11.9%-24.6%. Except for organic matter, the contents of other nutrients in the 20-40 cm soil layer were higher in treatments with higher the proportion of organic fertilizer replacement. In the 40-60 cm soil layer, only the content of alkali-hydrolyzed nitrogen increased significantly. The alkali-hydrolyzed nitrogen and available phosphorus contents were higher in the 0-20 cm soil layer under the treatments of bio-organic fertilizer replacing chemical fertilizer, while the organic matter contents were higher in the 0-40 cm soil layer under the treatments of decomposed sheep manure replacing chemical fertilizer. The comprehensive analysis of wheat yield, photosynthetic rate, nutrient utilization rate and soil nutrient indices of different treatments showed that the substitution of chemical fertilizer with 50% bio-organic fertilizer was the best treatment, which could be used as an important technical model for green and efficient production of wheat fields of the same type.





Characteristics and influencing factors of soil arthropod community in “Shushanggan” apricot forest in the Ili River Valley.

JIANG Zhicheng, CUI Dong YANG Yancheng, YAN Jiangchao, LIU Jianghui, CAO Jing, ZHANG Minru, WANG Qiaoli

2024, 43(11):  3394-3402.  doi:10.13292/j.1000-4890.202411.033

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We investigated the characteristics and influencing factors of soil arthropod community in “Shushanggan” apricot forests in Huocheng County of the Ili River Valley with different stand ages, including 4-, 8-, 10- and 14-year-old apricot forests and with barren land as the control. Soil arthropods were sampled by the Tullgren’s funnel method. We analzed the characteristics of the soil arthropod community and their relationship with environmental factors. The results showed that dominant groups of soil arthropods increased with the stand ages, with significant changes in common and rare groups. Dominant, common, and rare groups appeared in 14-, 10-, and 4-year-old “Shushanggan” apricot forests, respectively. The highest soil arthropod density and group number appeared in 14- and 4-year-old “Shushanggan” apricot forests, respectively. The vertical distribution of soil arthropod communities showed an aggregation in surface soil layer, with both density and group number decreasing downwards. The Shannon diversity index and evenness index of soil arthropods in 10-year-old “Shushanggan” apricot forests were the highest, while the dominance index was highest in 14-year-old “Shushanggan” apricot forests. Soil arthropod abundance was positively correlated with soil organic matter and total nitrogen (P<0.001). Results of redundancy analysis showed that axes 1 and 2 together explained 86.16% of the variation in community composition. Soil total nitrogen, organic matter, and available phosphorus were the main factors affecting the distribution of soil arthropod communities in “Shushanggan” apricot forests. Overall, there were significant changes in soil arthropod community composition, especially dominant groups, after the conversion of fallow land to “Shushanggan” apricot forests and during stand development. Our results provide scientific support for the planting and management of local “Shushanggan” apricot forests and the healthy development of forest fruit industry.





Response of macroinvertebrate communities in inland shallow lakes in Yinchuan Plain to dredging projects.

XU Lei, ZHAI Hao, LU Kangle, LIU Jiamin, WU Haitao, LIU Manhong

2024, 43(11):  3403-3411.  doi:10.13292/j.1000-4890.202411.005

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Shahu Lake, Mingcui Lake, and Liuxi Lake, which are typical inland shallow lakes in the Yinchuan Plain, are polluted by endogenous contaminants. Since 2015, dredging projects have been implemented to manage endogenous pollution, which has improved the ecological health of the lakes. To investigate the response of macroinvertebrates in inland lakes in Yinchuan Plain to the dredging project, a total of 16 sampling sites were set up for field surveys in 2015 (before dredging) and 2020 (after dredging) in the three lakes. The results showed that the average density and biomass of macroinvertebrates in Shahu Lake were lower after dredging than those before dredging, while the average density and biomass in Mingcui Lake and Liuxi Lake were higher after dredging than those before dredging. The dominant species and feeding functional groups of macroinvertebrates changed greatly after dredging. Non-metric multidimensional scaling (nMDS) results showed significant differences in macroinvertebrate community structure before and after dredging. The indicator species analysis showed structural changes in the macroinvertebrate community before and after dredging. Results of beta diversity partitioning showed that the beta diversity of macroinvertebrates was largely contributed by species turnover both before and after dredging. The dredging projects increased beta diversity and the contribution rate of species turnover to the beta diversity. Our results clarified the characteristics of the macroinvertebrate community of inland lakes in response to dredging, and provided a basis for ecological management and biodiversity conservation of urban shallow lakes.





Assessing the spatial distribution and driving factors of desert cyanobacteria by different species annotation methods.

2024, 43(11):  3412-3422.  doi:10.13292/j.1000-4890.202411.025

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Cyanobacteria, an important component of biological soil crusts in desert, exhibit low representation if studied using 16S rRNA amplicons with bacterial universal primers. The effectiveness of cyanobacteria 16S rRNA-specific primers has been verified by clone library studies, but appropriate species annotation methods for the study of amplicon by using this special primer are lacking. We conducted amplification comparison between the two primers, and compared cyanobacteria species annotation in different databases to establish species annotation and analysis process of desert cyanobacteria 16S rRNA amplicons. Combined with soil physicochemical properties, the diversity, community structure and environmental driving factors of cyanobacteria in algal crust soils in three regions of Gurbantunggut Desert were studied. The results showed that the cyanobacteria-specific primers could amplify desert cyanobacteria specifically, and that the cyanobacteria sequence accounted for 90.54%. The representative sequences of Operational Taxonomic Units (OTUs) obtained by the amplification had the optimal annotation effect when compared with Kraken2 standard library. The results showed that 4 orders, 13 families and 19 genera of cyanobacteria were obtained, and the dominant genera were Oscillatoria and Microcoleus. There was no significant difference in the α and β diversity, as well as abundance, of cyanobacterial communities in soil crust across different regions. The community structure was uniform, without obvious differentiation. Soil physicochemical factors, such as total nitrogen, ammonium nitrogen and nitrate nitrogen of algal crust, were significantly different in different regions of the desert (P<0.05). Results of Mantel test and correlation analysis showed that ammonium nitrogen content in crust soil was significantly correlated with the community structure of cyanobacteria (P<0.01). There was a significant positive correlation between Oscillatoria and microbial nitrogen, and a significant negative correlation between Microcoleus and nitrate nitrogen. These results could provide a better annotation and analysis process for the study of 16S rRNA amplicon of desert cyanobacteria, and provide a scientific basis for examining the community structure, species diversity and environmental driving factors of cyanobacteria.





Ecological water replenishment effect in Hutuo River and driving factors.

LI Yamin, ZHENG Lizhi, LI Jun, ZHANG Bing

2024, 43(11):  3423-3432.  doi:10.13292/j.1000-4890.202411.021

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Based on the experimental ecological water replenishment in the plain section of Hutuo River in 2018, we analyzed the water replenishment effect from three aspects: water level fluctuation, influence range, and groundwater storage variable. The influencing factors of groundwater depth change in Hutuo River plain were quantitatively analyzed by correlation analysis and principal component regression analysis to establish the corresponding mathematical model. The results showed that water replenishment had a significant effect on water level rise near Zhengding County, and that the area with water level rise accounted for 33.2% of the total area of the study region. The closer to the river, the faster the groundwater response and the greater the water level rise. Water replenishment effect in the middle and lower reaches were not significant. The results of principal component analysis showed that rainfall infiltration coefficient had the greatest influence on the change of groundwater depth, with a contribution rate of 24%. The contribution rates of upstream cumulative inflow and groundwater exploitation intensity to the change of groundwater depth were 20.26% and -19.72%, respectively, which were less important than the rainfall infiltration coefficient. The multivariate linear regression model established in the lower reaches of the Hutuo River had higher prediction accuracy. Taking the water supplement data of river section 1 as a reference, when the upstream water volume of river section 2 and river section 3 reached 4.78×10⁸ and 5.22×10⁸ m³ respectively, the downward trend of groundwater level in the corresponding river section could be reversed, while water replenishment of river section 4 was difficult and groundwater exploitation should be restricted. This study is of great significance for reasonable regulation of water diversion and sustainable development of regional water resources.





Spatial-temporal variations of carbon dynamics and their responses to climate change in Jiangsu coastal salt marshes.

WAN Anna, HAN Qifei, LI Chaofan, WANG Wenbiao, CUI Zhengnan

2024, 43(11):  3433-3442.  doi:10.13292/j.1000-4890.202411.006

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Coastal salt marshes are important blue carbon sink, which are sensitive to climate change. Assessing the carbon sink capacity of coastal salt marshes and their response to climate change is of great significance for China to achieving the carbon peaking and carbon neutrality goals. In this study, the DNDC (Denitrification-Decomposition) model was utilized to simulate the temporal and spatial variations of carbon sink in coastal salt marshes in different regions of Jiangsu Province, and to explore the responses of three typical salt marshes dominated by Phragmites australis, Suaeda salsa and Spartina alterniflora to long-term climate change. From 1981 to 2020, the total carbon sink of Jiangsu coastal salt marshes was 9.70 Tg C, and the total global warming potential (GWP) was -19.24 Tg CO₂-eq, with the largest total carbon sink and the negative effect on warming of Sheyang. Spatially, the carbon sink capacity and GWP in southern Jiangsu were greater than those in the north, and varied among the three types of salt marshes. The carbon sink capacity was in a descending order of Spartina alterniflora, Phragmites australis, and Suaeda salsa, while GWP followed an order of Phragmites australis < Spartina alterniflora < Suaeda salsa. In terms of interannual variation, net primary productivity (NPP) and GWP of the three salt marshes in various sites showed an increasing trend from 1981 to 2020. The carbon sink capacity varied greatly across different years, but the changing trend was not obvious on the whole. With the increase of temperature, NPP of Suaeda salsa and Spartina alterniflora increased, while that of Phragmites australis decreased. The changes in CH₄ and N₂O emissions were significantly greater than those of NPP. CH₄ and N₂O emissions increased significantly except for the different trends of N₂O emissions in Phragmites australis in different regions. Rainfall was positively correlated with NPP and CH₄ emissions in Phragmites australis and Spartina alterniflora, while Suaeda salsa showed an opposite pattern. Rainfall was positively correlated with N₂O emissions in three salt marshes.





Analysis and evaluation of changes in ecological health status in Fujian Province from 2001 to 2021.

CHEN Jianhui, WANG Xiaoqin, LIN Mengjin, SUN Weijing

2024, 43(11):  3443-3455. 

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Evaluating the ecological health of Fujian Province, the first pilot demonstration zone and experimental area for ecological civilization in China, would contribute to the advancement of the ecological civilization process. The critical challenges in ecological health assessment are how to construct a rational indicator system and objectively select crucial evaluation indicators that align with the research area. Grounded in the pressure-stateresponse (PSR) framework and ecological hierarchical network (EHN) framework, coupled with a quantitative screening model of network indicator system based on goal optimization theory, we calculated the ecological health composite index (EHCI) for Fujian Province from 2001 to 2021, and analyzed its spatial and temporal dynamics. The results showed that: (1) The final indicators obtained through the indicator system and screening model effectively captured ecosystem characteristics of the study area. The spatial variation of calculated ecological health status aligned with existing literature and realworld conditions, affirming the rationality of the constructed indicator system and screening model for the effective construction of the indicator system and objective selection of key indicators. (2) Over the two decades, Fujian Province had maintained a favorable ecological health status, with over 82% of the area being classified as excellent. The overall spatial distribution of ecological health status exhibited a characteristic pattern of high values in inland and low values in coastal areas, showing significant correlations with both human and natural factors. (3) During the 21 years of implementing the ecological province construction in Fujian, the overall ecological health had been improved. The area of ecological improvement surpassed degraded areas, with Zhangzhou, Longyan, and Quanzhou exhibiting the most significant improvements. Ecological improvement was primarily attributed to the effectiveness of soil erosion control and the progress of policies and projects related to the ecological environment.





Impacts of anthropogenic disturbance and green investment on organic carbon in the Yangtze River mainstream from 1980 to 2019.

XIE Ying, ZHANG Jun, WANG Ziteng, GUO Qingjun

2024, 43(11):  3456-3469.  doi:10.13292/j.1000-4890.202411.024

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To understand the impacts of human activities on organic carbon content in the Yangtze River mainstream, we analyzed the spatial and temporal variations of organic carbon content in the Yangtze River mainstream by collecting data from 1980 to 2019. Nonparametric analysis, variation partitioning analysis, and hierarchical partitioning were used to investigate the effects of anthropogenic disturbance and green investment. The results showed an increasing trend of dissolved organic carbon (DOC) concentration in the Yangtze River mainstream over the past 40 years, but a decreasing and then increasing trend of particulate organic carbon (POC) content. The spatial variations of DOC and POC contents over the river were significant during the Three Gorges Dam impoundment and operation periods, while the spatial variations were not significant during pre-Three Gorges Dam impoundment period. DOC transport fluxes generally increased from 2003 to 2019, while POC showed a fluctuating downward trend. The average total organic carbon flux from 2003 to 2019 was 3.66 Tg C·a^-1. Human activities and green investments contributed more organic carbon content during the wet season, which accounted for 66.33% and 44.00% of the variations in DOC and POC, respectively. Investment in industrial and domestic wastewater treatments had a greater effect on DOC and POC in the river during the dry season, whereas forestry investment contributed more on DOC in the wet season.





Spatial and temporal distribution of emission inventory of air pollutants from biomass burning sources in Hainan Province.

GUO Zhaowei, WANG Ping, LU Fang, ZHAO Youzhi, DING Wenci, HUANG Ding, DU Jiaxin

2024, 43(11):  3470-3477.  doi:10.13292/j.1000-4890.202411.029

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To clarify the pollution situation of biomass combustion sources in Hainan Province, we investigated the activity level data of biomass combustion sources in Hainan Province in 2019, established the emission inventory of seven pollutants from biomass combustion using the emission factor method, and analyzed spatiotemporal distribution and uncertainty of the emission inventory. The results showed that the emissions of CO, CO₂, SO₂, NO_X, NH₃, CH₄ and PM_2.5 from biomass combustion sources in Hainan Province in 2019 were 17779.77, 587732.18, 340.87, 1208.31, 308.69, 5674.55, and 4946.24 t, respectively. Open burning of rice straw had the highest contribution rate to CO, CO₂, SO₂, NO_X, NH₃, CH₄ and PM_2.5 emissions, while open burning of peanut and sugarcane straw had the highest contribution rate to CH₄ emissions. The distribution of air pollutant emissions from biomass combustion sources in Hainan Province was uneven. Haikou was the main emission area of pollution. The emission of air pollutants from biomass combustion sources in Hainan Province was uneven at the temporal perspective, and most of the emissions were concentrated in March, April, July and October, and mostly concentrated in the daily period of 3:00-6:00, 11:00-15:00 and 17:00-19:00. The uncertainty of CO₂ and NH₃ emissions from forest fires was the highest, being -29.5% to 28.5% and -27.7% to 29.6%, respectively. The uncertainty of CH₄ emission from open burning of straw was the lowest, being -15.5% to 12.5%.





A review on water conservation function of forests in Qinling region, Shaanxi.

MA Mengliang, LI Qiang, WANG Yaping, ZHANG Mingfang, LIU Shirong

2024, 43(11):  3478-3486.  doi:10.13292/j.1000-4890.202411.017

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Water shortage is becoming a global concern with climate change and socioeconomic development. Water conservation function of forests plays a key role in stabilizing regional water supply since forests can redistribute precipitation by interception, throughfall, stemflow, and soil water storage, with great implications for social-ecological system sustainable development. Because of high forest coverage, Qinling region is an important ecological security barrier and a significant water conservation area in China. However, few studies have been conducted to explore the water conservation function of forests in the Qinling region, leading to a vague understanding of its water conservation capacity. We summarized the concepts of water conservation and the evaluation methods of water conservation capacity. We then quantified land use and land cover changes in the Qinling region based on multi-source remotely-sensed data. Next, we introduced the performance of water conservation from three aspects: water regulation, water purification, and soil conservation. Based on literature, we revealed large temporal and spatial variations of water conservation capacity in Qinling region. We also synthesized the development of quantitative water conservation capacity in the Qinling region. The multi-scale, dynamic, and systematic research on forest water conservation function in the Qinling region should be strengthened.





A review of recent researches on wood-fall ecosystem in deep sea.

BAO Zeming, YU Kefu, CHEN Biao , WEI Yuxin

2024, 43(11):  3487-3501.  doi:10.13292/j.1000-4890.202411.023

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Wood-fall is an important organic matter and energy source in oligotrophic deep-sea environment, which has important impacts on biodiversity, species evolution and biogeochemical cycle. We reviewed recent research advances of deep sea wood-fall ecosystem from the following aspects: (1) The source, formation and ecological characteristics of deep sea wood-fall ecosystem; (2) The biodiversity, community composition and driving factors of deep sea wood-fall; (3) Ecological functions of deep sea wood-fall. In general, wood-fall ecosystem is a highly fragmented island-like ecosystem, which creates biodiversity hotspots in the oligotrophic seafloor by attracting specific benthic organisms and chemosynthetic microorganisms in deep sea. The unique three-dimensional structure of wood-fall can provide habitat and shelter for deep sea organisms, and promote the evolution of new species. The wood-fall is also a “stepping stone” for the migration and dispersal of species in the chemosynthetic ecosystem. The diversity and community structure of benthic organisms and microorganisms in deep sea wood-fall are influenced by environmental factors and ecosystem carriers. Moreover, chemosynthetic microorganisms in the wood-fall ecosystem can participate in the deep-sea biogeochemical cycling, especially the carbon cycle and sulfur cycle, through diverse pathways. Herein, we suggest to further study the deep-sea wood-fall ecosystem from the following aspects: (1) The community structure and ecological succession of deep sea wood-fall ecosystem; (2) The novel microorganisms and related functional genes related to cellulose degradation in the deep sea wood-fall ecosystem; (3) The driving mechanism of deep sea wood-fall microbiome on biogeochemical cycles.





Linear habitats in rural landscapes: characteristics, functions, and design strategies.

LI Peiwu, YUAN Xingzhong

2024, 43(11):  3502-3515.  doi:10.13292/j.1000-4890.202411.009

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Linear habitats refer to various types of linear landscape structures in rural landscapes that provide living environments for wildlife. They are widely distributed in rural areas, forming an essential basis for rural biodiversity. In the context of intensified agricultural development, the lack of awareness about the role of linear habitats has led to the degradation and even loss of rural ditches, rivers, streams, hedgerows, and other linear habitats, which urgently need to be protected. The research and restoration practices concerning linear habitats need to be further explored and expanded. We reviewed the current state of domestic and international research on rural linear habitats, explained the concepts and classifications of linear habitats, and discussed their biodiversity characteristics, including the symbiotic coexistence of native species, the coexistence of specialist and generalist species, and species migration with island-like features. We also summarized the functions of linear habitats as corridors, regulators, barriers, and carbon sinks. Based on this, strategies for the conservation and restoration of rural linear habitats were proposed from three aspects: habitat structure restoration, biological species recovery, and habitat network reshaping. Finally, based on the problems and challenges of existing research, we proposed suggestions for future research directions in rural linear habitats.





Evaluation of the dynamics of farmland shelterbelt network structure based on remote sensing.

ZHANG Xing, LI Jieling, LI Ying, DENG Rongxin, YANG Gao, TANG Jing

2024, 43(11):  3516-3525.  doi:10.13292/j.1000-4890.202411.019

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Farmland shelterbelts are an important part of the Three-North Shelterbelt Project. Detecting changes in the network structure of farmland shelterbelts is crucial for assessing the project’s construction and shelter effects. We proposed revised landscape index that considered the characteristics of farmland shelterbelts and remote sensing data to analyze the spatiotemporal variations in their network structure. Our evaluation method was applied to a typical area of shelterbelt construction in the north of Changchun. The results showed that the revised landscape index calculation was simpler and more suitable for medium and low-resolution remote sensing data. By dividing the research area and calculating the difference in landscape index between real and ideal conditions, the spatiotemporal variations in the farmland shelterbelt network structure could be effectively evaluated from three aspects, including the number of shelterbelts, their development status, and distribution. From 1985 to 2020, the structure of the shelterbelt network in the selected areas tended to be optimized, although closed-formed shelterbelt networks were less frequent and only about 14% of the shelterbelt networks graded as excellent in circularity degree. Our method provides a novel approach for evaluating the dynamics of shelterbelt network structure and can serve as a reference for the sustainable management of shelterbelts at the regional scale.





Prediction of suitable area of Camellia reticulata under climate change based on the Biomod2 ensemble model.

GAO Can, FAN Zhifeng, MA Changle, YANG Jianxin, GUO Shuailong

2024, 43(11):  3526-3536.  doi:10.13292/j.1000-4890.202411.020

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Camellia reticulata, a valuable wild winter flower plant species in Yunnan, has been listed as class Ⅱ national key protected wild species in China. C. reticulata has not been fully utilized in landscape applications due to its strict requirements for natural habitats. Climate change affects the distribution of plant species. Understanding the response of C. reticulata to climate change is the basis for its conservation, development and utilization. The distribution dynamics of C. reticulata from the Last Glacial Maximum to the end of this century was simulated with an optimal ensemble model (EM) in the Biomod2 package, based on climatic, topographic, soil and vegetational factors. The results showed that the optimal EM which composed of Generalized Boosted Models, Flexible Discriminant Analysis, Random Forest and optimized Maximum Entropy Models had better accuracy and performance compared to the single models, and being more simpler than the EM integrating by all model algorithms. Among the 31 environmental factors, temperature annual range was the main factors affecting the suitable habitat distribution of C. reticulata. Under the current climate scenario, C. reticulata is mainly distributed in the southwest China, south China and Taiwan, of which the highly suitable distribution region including most areas of Yunnan, southwestern Guizhou and northwestern Guangxi. Southern Cuona of Xizang, southeastern Fujian and southwestern Hainan also have scattered distribution of C. reticulata. Central region of Yunnan might be refugia site for C. reticulata in glacial age. With the warming climate, the suitable habitat of C. reticulata continues to spread to the surrounding four provinces. Future climate change would not cause large-scale migration or extinction of C. reticulata. Yunnan and its bordering provinces Xizang, Sichuan, Guizhou and Guangxi have always been stable and suitable areas for C. reticulata. The results indicated that global warming is conducive to the survival and reproduction of C. reticulata, and the suitable areas will spread northward. In the future, regions that are mainly considered suitable for introduction, domestication and gardening applications of C. reticulata would include northern Yunnan, southern Cuona city, southern Sichuan, southern Guizhou and coastal areas of Fujian.