Table of Content

10 June 2020, Volume 39 Issue 6

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Coastal wetland restoration based on mangrove Kandelia obovata substitution controllingSpartina alterniflora invasion: A case study of Aojiang Estuary in Zhejiang Province.

LIN Qiu-lian, GU Xiao-xuan, CHEN Xin-wei, GUO Xu-dong, CAI Li-zhe, LIN Li, CHEN Wan-dong, DONG Ying, FENG Hong-yu, CAI Hou-cai, ZHENG Chen-juan, CHEN Lu-zhen

2020, 39(6):  1761-1768. 

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Spartina alterniflora widely invades to the coastal wetlands in China. The ecological restoration mode of biological substitution that used mangrove to control the invasion of S. alterniflora has aroused widely concern. In this study, we evaluated the mangrove restoration of Kandelia obovata to control S.alterniflora in Aojiang Estuary of Zhejiang Province, China, by monitoring plant community structure and macrofauna diversity as well as the quality of water and sediment. The results showed that young mangrove community was simple in structure and well grown. The range of macrofauna community diversity index was 0-2.055 in mangrove site, and 1.053-2.805 in S. alterniflora site, which indicated that the environment of S. alterniflora was still well for macrofauna growth. This might be due to the young ages of K.obovata trees in this early stage of restoration. With weak purifying ability, the young forests had low ability to harbor macrofauna. This substitution could act as a typical case controlling S. alterniflora in its high latitude distribution region, which is expected to have better ecological functions after long-term management.

Geographic variations of hypocotyl and seedling growth traits for Kandelia obovata with different provenances.

YANG Sheng, LIU Xing, DENG Rui-juan, CHEN Qiu-xia, WANG Jin-wang, LU Xiang

2020, 39(6):  1769-1777. 

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Hypocotyl is a unique propagator of viviparous mangrove species such as Kandelia obovata. Understanding the geographical variations in the phenotypic traits of hypocotyls and seedlings of K. obovatawith different provenances, as well as the differences in nutrition requirements is critical for both conservation and genetic breeding of this valuable mangrove species. In this study, we collected mature hypocotyls of K. obovata of 11 provenances from five provinces in China. Based on their hypocotyl traits, we planted seedlings from 11 provenances at the Jingshanexperimental testing site in Zhejiang Province, and monitored their growth traits. Geographic variations of hypocotyls and seedlings were quantitatively analyzed through ANOVA, correlation analysis, and cluster analysis. We found that the phenotypic traits and nutrient contents of hypocotyls among the provenances were significantly different. In addition to carbon content and basal diameter, the coefficient of variations for various traits among the provenances was higher than those within the provenances, with the repeatability of the trait being higher than 85%. Hypocotyl length, height growth and biomass showed significant negative correlations with latitude and longitude, while they were positively correlated with mean annual temperature. Nitrogen and phosphorus contents showed opposite trends. There were positive correlations between: top diameter of hypocotyl and annual mean temperature, basal diameter of hypocotyl and annual mean temperature, and hypocotyl length and mean annual rainfall. Hierarchical cluster analysis further revealed that the 11 provenances could be classified into three groups: (1) HK and ZJ; (2) FD, YQ and CN; (3) BH, FCG, SZ, YX, LH and QZ. Clearly, there were large variations in phenotypic traits in K. obovata provenances, with each trait being subjected to strong genetic control. The 11 provenances of K. obovata were also clustered into three groups with distinct geographic features. The hypocotyl size and seedling growth were negatively correlated with the nitrogen and phosphorus contents of hypocotyl.

Artificial planting and natural spread of exotic mangrove species Sonneratia apetala and Laguncularia racemosa in Dongzhai Harbor, Hainan.

WANG Bing-yu, YANG Shan, LIU Qiang, ZHONG Cai-rong, Gul Juma, HE Fang-xing, YANG Yong

2020, 39(6):  1778-1786. 

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Hainan Dongzhai Harbor National Nature Reserve has a main base for introduction and domestication of exotic mangrove species in China, among which Sonneratia apetala and Laguncularia racemosa were introduced from Bangladesh in 1985 and from Mexico in 1999 respectively. After that, those species were introduced from the base to other wetlands in China. Currently, they have formed adult forests in many coastal wetlands in Hainan Island and Southern China, which caused concern about their possible adverse impacts on indigenous mangrove plant communities. In this study, we surveyed the artificial plantation and natural spread of S. apetala andL. racemosa in Dongzhai Harbor Nature Reserve in July 2019, and analyzed their spread routes and trends to offer a reference for the management of exotic species in mangrove wetlands. The results showed that artificial plantation of S. apetala was 40.56 hm², mainly distributed in the outer buffer and core zone, and the area of natural spread was 40.12 hm², most of which were scattered in the core zone and buffer zone. It is difficult to identify the spread route due to different planting times and decentralized planting sites. The artificial planting area of L. racemosawas 6.23 hm², mainly distributed in protected water and outer buffer zone, while the spread area was 0.53 hm², mainly in the buffer zone. Three main spread areas of L. racemosawere located around the relatively concentrated planting area, which could be identified that the individuals spread radially from planting areas to the areas as far as 3-5 km in straightline distance. Due to large density of seedlings in spread areas, there is an outbreak trend of L. racemosa. Those two exotic species spread into the indigenous mangrove communities and form mixed communities. Whether the exotic species will adversely affect native mangrove communities in the future remains to be clarified.

Dynamic characteristics of foliar nutrients in Kandelia obovata seedlings planted in Sporobolus alterniflorus invaded mud flat in Quanzhou Bay.

LI Yuan-yue, ZHAO Qiu-yi, CHEN Rong-bin, PAN Wen, GAO Su-rui, XIONG Zhang-jing, TANG Ye-xun, XIAO Zhen, TANG Shao-shuai

2020, 39(6):  1787-1794. 

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This study aimed to clarify the dynamic characteristics of and control factors on major nutrient element (C, N, P) contents and stoichiometric ratio in leaves of two-yearold mangroveKandelia obovata, and to understand nutrient use characteristics and nutrient limitation status of K. obovata in the second year after planting in Sporobolus alterniflorus invaded Luoyang River Estuary Wetland Reserve in Quanzhou Bay, Fujian Province. The C, N, P contents in leaves and aboveground biomass ofK. obovata during the growing season (June 2017-March 2018) in the second year after planting were measured. Results showed that total carbon content in leaves of two-year-old K. obovata ranged from 363.12 to 425.75 g·kg^-1. The range of total nitrogen content was 17.37-18.22 g·kg^-1, and the range of total phosphorus content was 1.33-4.06 g·kg^-1. The C∶N, C∶P, N∶P ratios of K. obovata leaves changed seasonally, showing a downward and then an upward trend. These results indicated high nutrient use efficiency in the two-year-oldK. obovata in coastal wetlands of Quanzhou Bay, and that nitrogen was the major limiting element of the two-year-oldK. obovata. Our results provided scientific guidance for comprehensive management of the replacement of invasive species S. alterniflorus with K. obovata, as well as the artificial planting and maintenance of mangroves.

Effects of composition and fluctuation of phytophagous insects on succession of mangrove communities.

LIU Wen-ai, XUE Yun-hong, ZHEN Wen-quan, SUN Ren-jie, FAN Hang-qing

2020, 39(6):  1795-1805. 

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To understand the taxonomic diversity, abundance and main characteristics of herbivorous insects in mangrove plants among different seasons, at different tidal levels and on different host plants, and their effects on mangrove canopy, and thus to assess the effects of phytophagous insects on mangrove community succession, five sections were established during the rainy (July) and dry (February) seasons. Insects were collected from different plant species in each section to estimate leaf feeding rate at high tide (H), mid-tide (M), and low tide level (L). Abundance and diversity of phytophagous insects were recorded. A total of 23 species of phytophagous insects were identified; with 13 species from Lepidoptera, 8 from Coleoptera, 1 from Orthoptera, and 1 from Acariforms. The abundant species were Ptyomaxia sp.,Lasiognatha cellifera,Chalioides kondonis,Ricaniasp., Phyllocnistis sp., Chalin larminati, and Lepidosaphes sp. The frequency of occurrence of Ricania sp. in rainy season and dry season was the highest (7.31 head·branch^-1). Leaf ingestion rate of mangrove plants in different sections was in a sequence of C5 > C2 ≥ C3 ≥ C1 in dry season and C5 > C2 ≥ C3 ≥ C4 in rainy season. In dry season, leaf feeding rate at different tidal levels followed the sequence of midtide ≥ high tide > low tide; in rainy season, it was midtide > low tide > high tide. The leaf feeding rate of different tree species during the dry season was Kandelia candel ≥Aegiceras corniculatum ≥Rhizophora stylosa ≥Avicennia marina, while in rainy season, it was K. candel > A. corniculatum>A. marina ≥R. stylosa ≥Bruguiera gymnorhiza ≥Sonneratia apetala ≥Excoecaria agallocha. Insects on the leaves of mangrove plants were generally small in stature, mainly phytophagous, and most of them have leaf-curling habits and adhesion characters. Species of natural predatory insects, such as ants, parasitoids and predatory spiders, are few. Once the abundance increases, those insects may become pests, with consequences on canopy stability. Therefore, phytophagous insects can influence the succession of mangrove communities.

Meiofauna community structure and marine nematode (a new record) in Futian mangrove wetland of Shenzhen Bay, Guangdong Province.

ZHU Hui-lan, LIU Meng-di, ZHOU Yu-hong, GUO Yu-qing

2020, 39(6):  1806-1812. 

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To clarify the composition and abundance of meiofauna, and dominant genera of freeliving marine nematodes, sediments were collected from Futian mangrove wetland in Shenzhen bay in the winter of 2018. The results showed that more than four meiofauna groups were recorded in the study area, including freeliving marine Nematode, Copepoda, Polychaeta, Oligochaeta and unidentified groups. Marine nematode was the most dominant group, accounting for 97.28% of the total abundance. The mean abundance of meiofauna was 490.73±465.09 ind·10 cm^-2. In total, 30 genera and 17 families of marine nematodes were identified from all the sampling sites. Dominant genera of marine nematode with dominance ≥5% were Paracanthonchus, Megadesmolaimus,Subsphaerolaimus, Terschellingia,Spinonema, Pseudochromadora and Pseudolella. Subsphaerolaimus major Nguyen & Gagarin, 2009, a new record of freeliving marine nematode species was measured and described. The main differences between the new record species and model species were compared.

Functional traits of macrobenthic assemblages and their influencing factors in mangrove plantations in Dianbai of Guangdong.

XIAO Hong, YIN Zhu-shi, ZHANG Min, CHEN Gui-zhu, PENG Yi-sheng

2020, 39(6):  1813-1822. 

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With more attention on ecological values of mangroves, mangrove afforestation programs have been continuously implemented globally. Previous evaluation on the effects of mangrove afforestation focused on quantitative aspects, such as afforestation area and survival rate, but few focused on its ecological functions. In this study, we analyzed the functional traits of macrobenthic assemblages and their correlation with environmental factors in mangroves of Shuidong Bay. In total, 40 species of macrobenthos from five phyla and six classes were identified in the one-year field sampling. The density, biomass and functional diversities of macrobenthic assemblages were significantly different among different dominant mangroves species and types. The ecological function of Sonneratia apetala plantation was similar to that of Avicennia marinanatural forest. Compared to the afforested Laguncularia racemosa monoculture, the mixed plantation can satisfy the habitat demand of more macrobenthic functional groups. The physicochemical properties of soil and water were significantly correlated with some macrobenthic functional traits. Environmental changes caused by mangrove colonization were mainly attributed to the diversification of macrobenthic assemblages.

Abundance and biomass of meiofauna in spring in Dongwan mangrove wetland of Fangchenggang, Guangxi.

ZOU Ming-ming, ZHU Hui-lan, GUO Yu-qing

2020, 39(6):  1823-1829. 

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In the spring of 2019, we collected sediment samples in four sections across 13 stations in the Dongwan mangrove wetland in Fangchenggang City, Guangxi, to investigate composition, abundance, and biomass of meiofauna. More than 11 meiofaunal groups were recorded,including free-living marine nematode, copepoda, polychaeta, oligochaeta, ostracoda, isopoda, bivalves, cumacea, halacaroidea, gastropods, cladocerans, and other unidentified groups. The mean abundance was (10364±8012) ind·10 cm^-2 across different sections. Nematodes were the absolutely dominant group, followed by copepods. The average abundance of nematodes was (9886±7746) ind·10 cm^-2, accounting for 95.38% of the total abundance of meiofauna, while that of copepods was (221±358) ind·10 cm^-2, accounting for 2.14% of the total. The meanbiomass of meiofauna was (10502±7894) μg·10 cm^-2 across different sections, with the descending sequence of Section 3 > Section 2 > Section 1 > Section 4.

Correlation between creek tidal distribution and vegetation coverage in the Yellow River Delta coastal wetland.

LIU Lu-yu, QU Fan-zhu, LI Yun-zhao, YU Jun-bao, YANG Ji-song, AN Cheng-bang

2020, 39(6):  1830-1837. 

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Based on Landsat TM/OLI images in 2005, 2010, and 2017, we analyzed the distribution and dynamics of tidal creek and vegetation coverage (VC) in the Yellow River Delta costal wetland by remote sensing and geographic information technologies. We conducted correlation analysis between tidal gully and VC in the study area using grid search method. The results showed that vegetation coverage of coastal wetlands in the Yellow River Delta continuously increased from 2005 to 2017. The area of low vegetation coverage decreased by 233.73 km², while that of high vegetation coverage increased by 165.85 km². From 2005 to 2017, the length and area of tidal creek in the Yellow River Delta coastal wetland continuously increased, and the frequency also increased. In 2017, the length and area of tidal gully in the southeast of the coastal wetland reached 216.13 km, and the area was 22.23 km². From 2005 to 2017, the length of tidal creek was negatively correlated with VC, and the tidal creek in 2010 and 2017 was significantly correlated with VC (P<0.05).

Fine-scale spatial pattern of Phragmites australis population in salt marshes of Yangguan, Dunhuang.

JIAO Liang, LI Fang, LIU Xue-rui, WANG Sheng-jie, ZHOU Yi

2020, 39(6):  1838-1846. 

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The spatial pattern of plant population is a key to study the relationship between plants and environment. It is a manifestation of the stability and life history strategies of plant population. To clarify finescale spatial pattern of Phragmites australis population in salt marsh of Yangguan, Dunhuang, we investigated their populations in four different sites across a gradient of wet zone, light salt zone, heavy salt zone, and desert zone. The Ripley K(d) function analysis method was used to examine the finescale spatial pattern of P. australispopulations and its ecological adaptation. The results showed that, from wetland to desert, the coverage, density, height, and above ground biomass of P. saustralisshowed a significant downward trend. The gap size significantly increased, while population density increased initially and then decreased. Across the gradient, the strategies of spatial expansion for P. australis population were changed from the clumped distribution as the main type, nonclumped distribution (random or regular distribution) as the supplement, to the random distribution as the main type and non-random distribution (clumped or regular distribution) as the supplement. Our results clarified the spatial pattern and driving factors of P. australis population in the inland riverine wetland, and served as a case study for further understanding ecological adaptation mechanism of clonal plants, and theoretical basis for scientific conservation and management of the inland riverine wetlands in the arid region.

The status and conservation of wetland birds in Sichuan Province.

LI Yun, WEI Yi, DONG Xin, HUANG Yan, WANG Pan, LI Cheng, WANG Bin, LI Jian-guo, ZHOU Cai-quan

2020, 39(6):  1847-1857. 

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To provide scientific basis for protecting wetland habitats and biodiversity in Sichuan Province, we surveyed wetland birds and habitats in Sichuan Province during December 2014 to December 〖JP2〗2018. A total of 27 survey zones (sites) were set up in the West Sichuan Plateau Area,〖JP〗 Southwest Sichuan Mountains Area, and Sichuan Basin Area. A total of 141 species of wetland birds were recorded. With 24 species that were recorded in previous documentation but were not recorded in this study, there were a total of 165 wetland bird species in Sichuan Province. The 141 species recorded in this study belong to 23 families and 11 orders, accounting for 73.33%, 65.71%, and 43.79% of the number of order, family and species of wetland birds in China, respectively. Among these species, seven species were the first grade national protected animals in China, and nine species were the second grade national protected animals, 19 species were the provincial protected species. Three species were listed in appendix Ⅰ, and eight species were listed in appendix Ⅱ in CITES. There were 20 species of resident birds, 23 species of summer visitor birds, 41 species of winter visitor birds, 59 species of tourist birds, and one species of stray birds. Among those species, 79 species (59.57%) belonged to the Palearctic Realm component, 33 species (23.40%) to the Oriental Realm one, and other 29 species (20.57%) to the widespread one. The species number and population size were largest in the Sichuan Basin Area, followed by the West Sichuan Plateau Area. Winter birds and tourist birds were mainly found in the Sichuan Basin Area and the Southwest Sichuan Mountains Area, while summer birds were mainly found in the West Sichuan Plateau Area. Our results indicated that there were abundant species of wetland birds in Sichuan Province. However, human activities had been destroying wetlands and affected species biodiversity in wetlands. We should strengthen the protection of the habitats of wetland-birds.

Characteristics of winter waterbirds community of lakes in central Yunnan, China.

YANG Wen-un, LIU Qiang, HE Xian, LI Yan-qiong

2020, 39(6):  1858-1864. 

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Lakes in central Yunnan Province are important wintering habitats for waterbirds in the YunnanGuizhou Plateau. It is important to reveal the characteristics of wintering waterbirds 〖JP2〗community for conservation and wetland resources management. In the winter of 2017-2018 and 2018-〖JP〗2019, we examined the waterbirds community characteristics by the point sampling method in lakes of central Yunnan (Dianchi Lake, Fuxian Lake, Qilu Lake and Xingyun Lake). A total of 40 species, 7 orders and 9 families were recorded. Waterbirds communities were dominated by ducks, accounting for 30% of the total species richness. Black-headed Gull Larus ridibundus was the dominant species, occupying 91.92% of total individuals. With non-parametric species richness estimates, we found that waterbirds richness was the highest in Dianchi (37.17±1.13), followed by Qilu (33.70±1.74) and Xingyun (32.05±1.80), and was lowest in Fuxian (17.78±0.43). Evenness index (Simpson index) of waterbirds was the highest in Fuxian (0.63±0.03), followed by Xingyun (0.53±0.07) and Qilu (0.52±0.05), and the lowest in Dianchi (0.11±0.03). Species richness was negatively correlated with the average water depth of the lake (r=-0.509,P<0.05), but not with lake size (r=0.286, P>0.05). Results of cluster analysis of community composition similarity showed that community composition in Dianchi was quite different from other three lakes. The community composition in Qilu and Xingyun were similar. In conclusion, Dianchi had high species richness (80.00% of total species) and abundance (89.69% of total number), which plays a great role in the conservation of waterbird diversity.

The diversity of fish communities and the effects of tidal intensity in the near-shore lower reaches of Yangtze River.

YAN Ming-jun, HU Chun-ting, LIN Dan-qing, MA Feng-jiao, XU Pao, LIU Kai

2020, 39(6):  1865-1874. 

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To understand the diversity of near-shore fish communities in the lower reaches of Yangtze River and the effects of tides on it, we collected fish samples and tide data during four consecutive seasons in the Jingjiang station from 2016 to 2017 and in the Changshu station from 2017 to 2018. The results showed that 61 species fishes were collected from the Jingjiang station, which belongs to 9 orders, 18 families and 47 genera. The dominant species were Hypophthalmichthys molitrix,Coilia nasus, Hemiculter bleekeri, Ctenopharyngodon idellus and Aristichthys nobilis. A total of 41 species were collected from the Changshu station, which belongs to 8 orders, 14 families, 34 genera. The dominant species were Hypophthalmichthys molitrix, Lateolabrax maculatus,Aristichthys nobilis, Parabramis pekinensisand Carassius auratus. Margalefindex, Shannon index, and Simpson index of fish communities in the Jingjiang station were higher than those in the Changshu station, whereas Pielou index was lower than that in the Changshu station. Results from SIMPER analysis showed that the average similarity of community composition among four seasons of the Jingjiang station and Changshu station were  64.5% and 64.7%, respectively. The average dissimilarity between two stations were 61.1%. Correlation analysis results of fish community diversity in each tidal cycle in different seasons showed that, at the 95% confidence interval, species richness, catch weight, Shannon index of the Jingjiang station were significantly positively correlated with the maximum tidal range on the sampling day (P<0.01); the Margalef index and Simpson index were significantly positively correlated with the maximum tidal range (P<0.05), while the number of catches was not significantly correlated with the maximum tidal range. Species richness in Changshu was significantly positively correlated with the maximum tidal range (P<0.05), whereas other indicators were not correlated with the maximum tidal range. Our results provide basic data for the study of fish community diversity, and thus would contribute to the conservation and sustainable utilization of fish resources in the lower reaches of Yangtze River.

Ecosystem services valuation and its uncertainty in wetlands surrounding Chongming Island.

MA Yu-xi, LI Xiu-zhen, LIN Shi-wei, XIE Zuo-lun, XUE Li-ming, HAN Ji

2020, 39(6):  1875-1883. 

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An evaluation index system was established to evaluate ecosystem services in wetlands surrounding Chongming Island. The total value of ecosystem services was 15.18 billion CNY in 2017. Among all the examined ecosystem services, the value of cultural service was the largest, being 10.42 billion CNY. Regulating and providing services were valued at 4.672 and 0.087 billion CNY respectively. Cultural service accounted for 69% of the total value, indicating a great potential of tourism service provided by the wetlands. Due to the limiting factors including data availability and choice of assessment techniques, there were uncertainties in our assessment outputs. Spatialtemporal heterogeneity and socioeconomic preference of willingness to pay would affect the valuation. We discussed the factors that may lead to assessment uncertainties, including service supply, willingness to pay, and evaluation methods. Our results from this study would provide improvement directions for future studies.

Characteristics of modern pollen rain and its relationship to climatic factors in the Honghe region of southern Yunnan.

LI Xi-jin, MENG Hong-wei, SUN Qi-fa, ZHANG Guo-fu, HUANG Lin-pei, SHEN Cai-ming

2020, 39(6):  1884-1895. 

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Few studies are available on the relationship between modern pollen rain and climatic factors in the tropical and subtropical regions of low latitude in China. In this study, surface sediments of 43 water bodies (lakes, reservoirs, and ponds) were analyzed to explore the characteristics of modern pollen rain and its relationship to climatic factors in the Honghe region of southern Yunnan. Pollen analysis of surface sediments showed that pollen spectra of surface sediments from water bodies were characterized by abundant pollen and high arboreal pollen percentages. Arboreal pollen were dominated by Pinus, Alnus, and Fagaceae, while herbaceous pollen mainly included Poaceae, Asteraceae, and Cyperaceae. Pollen spectra also contained some fern spores (such as triletes) and algae (such as Pediastrum). Meanwhile, modern meteorological data of these water bodies were obtained by linear interpolation of 1961 to 2010 (50-year) from 13 meteorological stations in the Honghe region of southern Yunnan. Redundant analysis of modern pollen and climate data was used to examine the effects of climate factors on the spatial pattern of modern pollen rain. The results of redundancy analysis showed that the six climatic factors controlling modern pollen rain are mean annual precipitation and temperature, precipitation in spring and dry season, and temperature in July and rainy season. An increase in temperature resulted in vegetation dominated by evergreen broadleaved forest, and a decrease in precipitation caused an expansion of pine forest. Our results provide theoretical support for paleoclimate reconstruction using fossil pollen record.

Environmental changes over the past 1200 years in the catchment of Yangzonghai Lake, Central Yunnan.

YU Xiao-shan, MENG Hong-wei, HUANG Lin-pei, SUN Qi-fa, WANG Min, ZHANG Hu-cai, SHEN Cai-ming

2020, 39(6):  1896-1910. 

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We carried out pollen/charcoal analyses on sediments of a 78cm core from Yangzonghai Lake to study vegetation succession, climatic change, and forest fire history over the past 1200 years in the catchment of Yangzonghai Lake, central Yunnan. The age-depth framework was established using an AMS ¹⁴C dating of plant remnants at the bottom and ²¹⁰Pb dating at the top. The results showed that: (1) There were four stages of vegetation changes in the catchment of Yangzonghai Lake over the past 1200: the first one was a warm and dry stage (780-1630 AD), when vegetation was dominated by mixed forest of pine and oak with few herbs; the second stage was a cool and wet stage (1630-1860 AD), when vegetation was still dominated the mixed forests of pine and oak, but with a decrease in the forest proportion and substantial fluctuations, and with a significant increase in herb proportion; it was followed by a cold and dry stage (1860-1950 AD) and the subsequent a warm and dry stage (after 1950 AD), when vegetation was strongly disturbed by human activities, which may have become the dominant factor driving vegetation. (2) Across the past 1200 years, a warm period (780-1630 AD) and a cold period (1630-1950 AD), corresponding to Medieval Warm Period and Little Ice Age respectively, occurred in the catchment of Yangzonghai Lake. Moreover, the hydrothermal conditions showed a pattern of warm dry and coldwet, which occurred almost synchronously in the adjacent areas such as Tiancai Lake and Erhai Lake in northwest Yunnan and eastern Qinghai Tibetan Plateau. During the whole warm period, temperature was stable with a little bit more fluctuation in the warmest stage from the middle of the 12th century to the middle of the 15th century. Climate during the Little Ice Age showed two periods, namely a cool-wet period from 1630 to 1860 AD and cold-dry period from 1860 to 1950 AD. The dominant forcing of climate change over the past 1200 years in the catchment of Yangzonghai Lake was solar forcing associated with regional and global ocean atmosphere coupling. (3) Forest fire increased gradually over the past 1200 years in the catchment of Yangzonghai Lake, a trend consistent with population growth and human activities, indicating that human activities have gradually become one of the dominant driving forces of environmental change.

Temporal dynamics of carbon isotope composition of stem respiration and its controlling factors in Pinus massoniana trees in subtropical China.

YAN Li-fei, YANG Qing-peng, GUAN Xin, HUANG Ke, ZHANG Shi-meng, ZHAO Feng-xia

2020, 39(6):  1911-1920. 

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Stem respiration plays an important role in global carbon cycle, the temporal and spatial variations of which drive the responses and feedback of global carbon pool to climate change. There is still large uncertainty, however, about the temporal variation of stem respiration, especially its stable carbon isotope composition (δ¹³C). To understand the temporal variation of stem respiration and its stable carbon isotope composition, we monitored stem respiration from six individuals of Pinus massoniana by the chamber method and the Picarro observation system based on cavity ringdown spectroscopy (CRDS) during August 2018 to October 2019. The sap flow rate and stem temperature were also measured. The results showed that: (1) there was no obvious diurnal variation of stem respiration rate and δ¹³C value, which were not significantly correlatedwith sap flow and stem temperature. (2) There was an obvious seasonal variation of stem respiration rate, ranging from 0.08 to 1.61 μmol·m^-2·s^-1. Stem temperature explained 82% of the seasonal variation of stem respiration rate. (3) δ¹³C of stem respiration increased first and then decreased. The average δ¹³C value (-23.25‰±0.91‰) of stem respiration in the non-growing season was significantly higher than that (-27.93‰±0.25‰) in the growing season. Our results suggest that stem respiration and its carbon isotope composition were different in different time scales, and that the seasonal dynamics of stable carbon isotope composition of stem respiration provides a new perspective for understanding stem respiration and possible intrinsic mechanisms.

Spatial and temporal variation of the responses to global warming hiatus in the growth period of Populus euphratica in China’s oases.

SI Wen-yang, LIU Pu-xing, ZHANG Ming-jun, ZHANG Wen-xia, QIAO Xue-mei

2020, 39(6):  1921-1928. 

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Based on data of daily average temperature from 48 meteorological stations in Populus euphratica distribution areas of Chinese oases from 1960 to 2017, we analyzed spatiotemporal responses of the start and end dates as well as the number of days of growing period of P. euphratica to global warming hiatus, with multiyear trend line, correlation analysis, and partial leastsquares regression. The results showed that the change rates of start date, end date and the number of days of growing period of P. euphratica in Chinese oases from 1998 to 2012 were -0.764, -0.328, and 0.535 d·10 a^-1, respectively. In comparison with temporal sequence between 1960 and 2017 and that between 1960 and 1998, the start date had been postponed, the end date had been advanced and the number of days of growth period had been dwindled during 1998-2012, indicating high sensitivity to the global warming hiatus and with the highest sensitivity of the end date. In accordance to spatial variation, the response to global warming hiatus decreased from the southwest to the northeast, with more than 47% of stations showing the trend of postponed start date, advanced end date, and shrinking growing period. Response of growing period of P. euphratica to global warming hiatus varied across oasis sites. P. euphratica in Hetao oases had prominent response to global warming hiatus, while the response of P. euphratica in Qaidam oases was weak. Results of causal analysis showed that Asia polar vortex area index, Qinghai-Tibet Plateau index, and Westerly Circulation index were major factors driving the responses of P. euphratica to global warming hiatus.

Effects of nitrogen addition on soil microbial community structure in a subtropical Phyllostachy pubescens forest.

CHENG Lei, ZHOU Jia-cong, LIN Kai-miao, ZHANG Qiu-fang, ZHOU Jin-rong, LIN Qiao-yu, ZHENG Wei, WANG Tao, CHEN Yue-min

2020, 39(6):  1929-1937. 

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Nitrogen deposition affects aboveground (such as plant productivity and composition) and belowground properties (such as soil nutrient cycling) in forest ecosystems, with consequences on the structure and function of soil microbial community. We simulated nitrogen deposition at three levels \[N0 (0 kg N·hm^-2·a^-1), N20 (20 kg N·hm^-2·a^-1), N80 (80 kg N·m^-2·a^-1)\] in a Phyllostachy pubescens forest in Daiyun Mountain in subtropical China for three years. We measured soil physicochemical properties, humification index, and microbial phospholipid fatty acids to clarify how nitrogen addition affects soil nutrients and microbial community structure in P. pubescens forest. The results showed that N20 treatment significantly increased soil humification index, reduced total content of alkaline cations (K⁺, Na⁺, Ca²⁺, Mg²⁺), Grampositive bacteria (G⁺), Gram-negative bacteria (G^-), total phospholipid fatty acids (total PLFAs), and the ratio of G⁺/G^-. Compared to N20 treatment, N80 treatment significantly increased the contents of soil nitrate, G⁺, G^-, total PLFAs and G⁺/G^-(P<0.05). Results of correlation analysis showed that soil humification index was negatively correlated with soil microbial biomass. Results of redundancy analysis showed that the total amount of alkaline cations and available nitrogen were important environmental factors driving the changes of microbial community structure. Our results indicated that nitrogen addition may change soil microbial nutrient requirements in the P. pubescens forest, which in turn affects soil microbial community structure.

Phytolith-occluded organic carbon sequestration of typical communities in Songnen grassland.

ZHONG Li-xiang, JIE Dong-mei, LI De-hui, CHEN Jie, CHEN Yu-fen, CHEN Nian-kang, BAHAYILA Halian, WANG Fang

2020, 39(6):  1938-1945. 

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Phytolith-occluded organic carbon (PhytOC) sink is an important component of grassland carbon sink. In this study, we extract phytoliths by Walkley-Black type, from Poaceae community, Asreraceae community and Cyperaceae community in Songnen grassland. PhytOC was measured by alkali dissolution spectrophotometry. PhytOC content of phytoliths, PhytOC content of biomass and phytolith content were calculated. We estimated the rate of PhytOC sequestration based on the amount of PhytOC in Songnen grassland and analyzed the differences in capacity of PhytOC sequestration among those three communities. The results showed that the average rate of PhytOC sequestration in Songnen grassland was 1.67 t CO₂·hm^-2·a^-1. There was a significant negative correlation between phytolith content and PhytOC content of phytoliths (P<0.05, R²=0.94). The capacity of PhytOC sequestration varied among different communities, with 2.151 kg CO₂·hm^-2·a^-1 for Cyperaceae community, 1.716 kg CO₂·hm^-2·a^-1 for Poaceae community, and 1.218 kg CO₂·hm^-2·a^-1 for Asreraceae community. PhytOC sequestration was affected by community composition, aboveground net primary productivity, and the formation processes of phytoliths. Our results could enrich the basis for studying grassland carbon cycling.

Responses of ecological stoichiometric characteristics and functional traits of Heteropappus hispidus to slope aspect.

NIU Ya-lin, LI Kong-ming, WANG Xue-yan, WEI Chen, WANG Wei-xuan, SU Hao-hai, ZHANG Xiao-fang, CAO Jian-jun

2020, 39(6):  1946-1955. 

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Slope aspect has important effects on leaf ecological stoichiometric characteristics and functional traits. Uncovering ecological stoichiometric characteristics and leaf functional traits of plants under different slope aspects can enhance our understanding of the responses and adaptation strategies of plants to environmental change. We examined the changes in ecological stoichiometric characteristics and functional traits of leaves of Heteropappus hispidus from Lanzhou with slope aspect changing from sunny slope to shady slope. Leaf C content, leaf C∶P, and leaf N∶P were greater under the sunny slope (408.12 g·kg^-1, 348.61, 29.71, respectively) than that under the shady slope (400.75 g·kg^-1, 196.69, 16.60, respectively). Leaf N content and leaf C∶N were similar but leaf P content was significantly lower under the former (34.81 g·kg^-1, 11.72, and 1.67 g·kg^-1, respectively) than under the latter (34.07 g·kg^-1, 12.24, and 2.56 g·kg^-1, respectively). Specific leaf area and leaf water content had no difference between sunny slope (10.55 cm²·g^-1 and 59.06%, respectively) and shady slope (9.70 cm²·g^-1 and 60.65%, respectively), while leaf dry matter content and leaf area were significantly lower under the sunny slope (0.14 g·g^-1 and 0.31 cm², respectively) than under the shady slope (0.15 g·g^-1 and 0.41 cm², respectively). The growth of H. hispidus in this area was mainly restricted by phosphorus availability. On the sunny slope, specific leaf area, leaf water content, and leaf area were the dominant factors affecting leaf C content, leaf P content, and leaf C∶N, respectively. On the shady slope, leaf dry matter content was the dominant factor affecting both leaf C content and leaf P content, and all four indicators of leaf functional traits had an effect on leaf N content and leaf C∶N, with leaf area being the first important factor, followed by specific leaf area. Our results indicated that slope aspect influenced the ecological stoichiometric characteristics and functional traits of leaves of H. hispidus. Thus, studies combining ecological stoichiometric characteristics and plant functional traits will be conducive to our comprehensive understanding of plant adaptation strategies.

Effects of biodegradable plastic film mulching on soil moisture, temperature, salinity and yield of cotton field.

DENG Fang-ning, LIN Tao, HE Wen-qing, XIA Wen, ZHANG Hao, ER Chen, CHEN Chun-fan, TANG Qiu-xiang

2020, 39(6):  1956-1965. 

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To examine the effects of biodegradable film mulching on soil moisture, temperature, salinity and yield of cotton fields, four kinds of biodegradable mulch films (T1, T2, JF, BSF) and ordinary PE mulch film (control) were applied in the oasis cotton filed of southern Xinjiang. We analyzed the roles of different biodegradable mulch films in preserving soil moisture, rising soil temperature, restraining soil salinity, and their effects on yield of cotton fields. The results showed that watersaving capability of BSF treatment was comparable to that of PE film, while that of T1, T2 and JF treatment was not comparable with PE film. The effect of restraining soil salinity of JF and BSF treatments was better than that of PE film, with mean salt content of 0-60 cm soil layer of JF and BSF treatments being 0.3 and 0.4 g·kg^-1 lower than that of PE film, respectively. The effect of restraining salinity of other treatments was lower than that of PE film treatment. Soil temperature in JF and BSF treatments was 0.3 and 1.6 ℃ higher than that of PE film treatment respectively, while that of other treatments was lower than that of PE mulch. Different biodegradable mulch films did not differ in their effects on ET_a, but significantly varied in their effects on the number of bolls per plant and water use efficiency. The earlier the mulch films degraded, the less number of bolls per plant, the lower water use efficiency. Seed cotton yield under BSF treatment was higher than that of other treatments, but was 20.2% lower than that of PE film treatment. Our results provide scientific support for the screening and safety evaluation of biodegradable mulch films in the study region.

Effects of regulated deficit irrigation and biochar application on growth, yield and water use efficiency of soybean.

LI Ming-yang, WANG Li-xue, JIANG Zhan-bo, JIANG Xi, MENG Wei-zhong

2020, 39(6):  1966-1973. 

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To clarify the effects of biochar application and regulated deficit irrigation on soybean, a pot experiment was conducted with randomized block design and using soybean Kaiyu 12 as experimental material. We examined the effects of different biochar application rates \[B₀ (0 t·hm^-2), B₁ (6 t·hm^-2), B₂ (12 t·hm^-2)\] and different degrees of regulated deficit irrigation \[W₁ (full irrigation, 70% field capacity), W₂ (mild regulated deficit irrigation, 55%-60% field capacity), W₃ (severe regulated deficit irrigation, 45%-50% field capacity)\] on the growth, yield, and water use of soybean. The results showed that leaf area index and underground dry matter accumulation of soybean were not affected by the mild regulated deficit irrigation, but increased with the increasing biochar application rates. The aboveground dry matter accumulation decreased with the aggravation of the regulated deficit degree, but increased when 12 t·hm^-2 biachar was applied. Both regulated deficit irrigation and biochar could affect water consumption of soybean. Water consumption decreased with the aggravation of the regulated deficit degree. Biochar application with a rate of 6 t·hm^-2 had the highest water consumption, but was conductive to the formation of yield. Compared with full irrigation without biochar (W₁B₀), mild regulated deficit irrigation with applying 6 t·hm^-2 biochar (W₂B₁) increased yield by 16% and water use efficiency by 21.4%. Therefore, mild regulated deficit irrigation with 6 t·hm^-2 biochar application (W₂B₁) could effectively improve yield and water use efficiency of soybean.

Changes of endogenous hormone contents during seed germination of Anemone rivularis var. floreminore and germination mechanisms.

GE Wen-jing, BU Hai-yan, WANG Xue-jing, XIA Yu-bin, DU Guo-zhen

2020, 39(6):  1974-1982. 

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Seed germination and dormancy are regulated by endogenous hormones. In this study, we investigated whether endogenous hormone levels are associated with seed germination ofAnemone rivularisvar.floreminore in 12 h/12 h light/dark and 24 h dark. The endogenous hormone contents of abscisic acid (ABA), gibberellins (GAs), transzeatin (ZT), and indole-3-acetic acid (IAA) were detected in dry, imbibed and germinated (emerged radicle) seeds using reversed phase highperformance liquid chromatography (RP-HPLC) with ultraviolet detection. Our results showed that light stimulated ZT and suppressed ABA accumulation before seedling emergence, and promoted the release of ZT to ABA inhibition during seed germination. The ratios of ABA/ZT, ABA/GAs and (ABA+IAA)/(GAs+ZT) in germinated seeds were higher in the dark than in the light. These results were consistent with the fact that A. rivularis var. floreminore seeds germinated more efficiently in the light than in the dark. Compared to that in dry seeds, IAA content rapidly declined in early imbibition in both light and dark periods, (ABA+IAA)/(GAs+ZT) ratio decreased significantly and ABA/GAs ratio increased. The effects of light on hormone levels were weakened when the first seed started to germinate. The ninth day was the key time point for the changes in hormone level during A. rivularis var. floreminore seed germination. In brief, seed germination was not always associated with an increase in GA content or a decrease in ABA content. Abundant sunlight and strong solar radiation in the alpine meadows contribute to the dormancy release during the germination of A. rivularis var. floreminore seeds by, at least partly, affecting hormone levels.

Effects of exogenous ATP on the growth of Brassica campestris seedlings under salt stress.

LAI Jing, LI Qiao-li, ZHANG Xiao-hua, LIANG Juan-hong, ZHANG Teng-guo

2020, 39(6):  1983-1993. 

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We examined the effects of exogenous ATP treatment on the growth of Brassica campestris seedlings under salt stress, and clarified the roles of signal molecules, hydrogen peroxide (H₂O₂) and calcium ion (Ca²⁺) in the ATP regulation of salt tolerance. The results showed that, compared with the single NaCl treatment, ATP+NaCl treatment decreased the number of dead cells, ROS (O₂^-_· and H₂O₂) content, ion (Ca²⁺, Na⁺, Cl^-) content, MDA content, Na⁺/K⁺ ratio, and relative electrical conductivity. The chlorophyll, proline, soluble sugar content, antioxidant enzyme (SOD, POD, CAT, APX) activity, transcriptional regulation of antioxidant enzyme genes (CAT, SOD, APX, GR), NADPH oxidase genes (RBOHD, RBOHF), P5CS1 gene, MAPK kinase genes (MAPK3, MAPK6), and salt tolerance genes (NHX1, SOS1) were all elevated. Compared with ATP+NaCl treatment, the relative electrical conductivity, MDA, chlorophyll, proline, soluble sugar, the activities of antioxidant enzymes (SOD, POD, CAT, APX), and the expression of the above genes were decreased when treated with ATP+NaCl+inhibitors (DPI, DMTU and EGTA). These results indicated that exogenous ATP application could increase cell activity, ROS content, ion content, chlorophyll content, osmotic regulator, antioxidant enzyme activity and related gene expression in B. campestris under salt stress. In addition, signal molecules of H₂O₂ and Ca²⁺ were involved in the ATP regulation of enhancing salt tolerance in B. campestris.

Carbon, nitrogen, and phosphorus stoichiometry and nutrition strategy of invasive species Mikania micrantha with three invasive degrees and native species Siegesbeckia orientalis.

WANG Ju-hong, CHEN Wen, ZHANG Yan-fang, LI Yun, SHI Shen-jing, ZHENG Jia-yu, CHEN Yan-xia

2020, 39(6):  1994-2003. 

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Biological invasion is one of the most important threats to global biodiversity and ecosystem functioning. In this study, we measured carbon, nitrogen, and phosphorus content and their ratios in alien species Mikania micrantha with three invasive degrees and native species Siegesbeckia orientalis to explore the nutritional strategy of M. micrantha. The results showed that for M. micrantha, soil N and P contents in the three habitats were high. The contents of soil C, N, AN, and AP with mild invasion were higher than that in the other two habitats, showing that soil nutrients reduced with the increasing invasion. Leaf N content in M. micrantha under three invasive degrees were significantly greater than that of root and stem. Under severe and median invasion degrees, stem P content was significantly higher than root P and leaf P, indicating that more P was allocated to stem with increasing invasion. In contrast, more N was allocated to leaf. N∶P in root and stem of the three invasion degrees were lower than that in leaf. In particular, stem N∶P of mildly invasive M. micrantha was significantly lower than that of the other two invasion degrees, suggesting that the greatest relative growth may occur in stem and root during invasion. Ratios of N∶P and C∶P in root and stem of M. micrantha were significantly lower than that of native species S. orientalis, implying that M. micrantha may grow faster than native species with a “growth competition strategy”. Significant negative correlations were found between C∶N and N∶P in both root and stem for M. micrantha, showing a tradeoff between growth and storage. There was a significant positive correlation between stem P of M. micrantha and soil C and N (0-10 cm), and between root P and soil AP (10-20 cm), indicating that M. micrantha may increase the absorption and utilization of P with increasing soil nutrition. Growth and nutrient strategies varied under different resource conditions (e.g., growth competitive strategy), as well as fundamental tradeoffs between growth and storage, which all contribute to the successful invasion of M. micrantha.

Effects of soil thickness on soil microbial community function of green roof.

YU Wei, JIN Xue-mei, JIANG Zhen-yang, YUAN Zai-xiang, GUAN Qing-wei

2020, 39(6):  2004-2013. 

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We examined the relationship between soil microbial community function and soil  thickness in green roof under three soil  thicknesses (40, 70, and 100 cm), by using a control simulation test method. Our aim was to reveal the role of soil layer thickness in improving the overall ecological function of green roof from a perspective of soil biology. The results showed that the overall metabolic activity (AWCD) of soil microbial community, the metabolism of carbon sources CI, AI and MI, and the McIntosh U index under the 100 cm soil layer  were significantly larger than those under the other two thicknesses (P<0.05), while most of these indicators did not differ between 70 cm and 40 cm soil layer  (P>0.05). Results from PCA ordination plot displayed that carbon source metabolic ability of soil microbial community in 100 cm soil layer was the strongest, while that in 70 cm and 40 cm soil layer was generally similar. Soil thickness significantly affected the annual growth rate (AGR) of diameter at breast height of Ligustrum lucidumAit. AGR increased by 11% from 40 cm to 70 cm, and by 15% from 70 cm to 100 cm. The effects of soil thickness in green roof on soil microbial community function and plant growth rate had a good consistency. Reasonable soil thickness can provide suitable growing environment for roofing organisms and promote the maximization of their ecological benefits.

Characteristics of avian diversity and birdstrike prevention and control at Taiyuan Wusu International Airport.

CHENG Lei, WANG Xiao-bin, XU Yan-zhao, CAI Xiu-min, XUE Wei-wei, WAN Xia

2020, 39(6):  2014-2023. 

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Avian activities in areas around the airport are potential risks to flight safety. It is of great significance to understand the characteristics of avian diversity at the airport for birdstrike prevention and control. From October 2018 to August 2019, we investigated avian diversity in the internal and external areas of Taiyuan Wusu International Airport using the method of line sampling and net catching. A total of 75 species, belonging to 31 families of 13 orders, were recorded, with the proportion of breeding and non-breeding birds being 60% and 40%, respectively. Using the software of EstimateS to estimate species richness of birds in the survey area, ACE value was 81 species and ICE value was 98 species, indicating that the survey covers 76.53%-92.59% of the total bird species, with a good survey effect. To clarify the impacts of surveyed birds on bird strike prevention and control, we calculated the hazard index with the importance values (IV) and risk factor of the species. The results showed that there were 10 very dangerous bird species at the airport in the whole year, including Anas zonorhyncha, Hirundo rustica,Anas platyrhynchos, Pica pica, Phasianus colchicus, Columba domestica, and Streptopelia chinensis. The results of clustering analysis of avian diversity in six different habitats showed that habitats with strong human disturbance, including residential areas and road greenbelts, had lower species diversity (H=1.35±0.08). Other four habitats, including airport lawn, pond-tideland, farmland, and artificial forest land, were less disturbed by human activities and had higher species diversity (H=1.66±0.04). Therefore, in the bird strike prevention work of airport, it is necessary to carry out targeted management of the ecological environment around the airport anddevelop targeted prevention and control strategies to cope with the activities of dangerous birds.

Using stable isotopes to assess food source and trophic level of terrestrial animals in Mawan cave of Fenggang in Guizhou.

XU Cheng-xiang, DU Wei-feng, ZHANG Si-qiang, ZHANG Yan, YANG Rui-quan, LIU Xi-zhu

2020, 39(6):  2024-2032. 

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We measured the isotope ratios of δ¹³C and δ¹⁵N in cave animals and their organic carbon sources in Mawan cave of Fenggang, Guizhou, and further analyzed trophic level relationship and food sources of the cave ecosystem. The results showed that the values of plant δ¹³C in the cave ranged from -41.78‰ to -38.80‰, which is lower than that of plants out the cave. The δ¹⁵N of plants in the cave ranged from -1.31‰ to 1.23‰, which is within the range of terrestrial organic matter. The δ¹³C of soil organic matter in the cave ranged from -31.09‰ to -24.95‰, while the δ¹⁵N of soil organic matter in the cave ranged from -1.08‰ to 7.72‰. The δ¹³C of cave animals ranged from -30.41‰ to -12.02‰, while their δ¹⁵N ranged from 2.07‰ to 8.94‰. The contribution rate of cave soil organic matter to animals was more than 72%, being higher than that of plants, indicating that soil organic matter was the main food source for cave animals. There were four trophic levels in the food web. Plants were the first trophic level. Tipula sp., Gastropoda, and Diolopoda were the second trophic level. Distrammena sp., Mecistocephalus sp. were the third trophic level. Most of Araneae groups were the third or fourth trophic level. Our results indicate that the trophic levels of most animals were relatively stable in the cave. A few animals from same species have different trophic levels in different light zones, whereas different species belonging to the same group would be at different trophic levels in the same light zone.

Effects of two kinds of pesticides on activities of antioxidant enzymes and the expression of bcl6bgene in Oryzias latipes.

TIAN Shu-xin, YANG Shu-yu, ZHAO Wen-ge, YU Dong

2020, 39(6):  2033-2041. 

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To clarify the effects of atrazine and chlorpyrifos on the activities of antioxidant enzyme and the gene expression of B cell CLL/lymphoma 6B (bcl6b) in muscle of Oryzias latipes, we measured superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-PX) activity, and bcl6b mRNA expression withOryzias latipes being treated by exposure to different concentrations of atrazine and chlorpyrifos alone or together at different periods. The results showed that activities of antioxidant enzyme (SOD, GSH-PX) in muscle of Oryzias latipes significantly decreased with increasing pesticide concentration, while the relative expression of bcl6b mRNA significantly increased. After recovered for 30 days, the activities of both antioxidant enzymes (SOD, GSH-PX) were significantly increased as compared to their counterparts at the end of recovery in the moderate concentration or high concentration group, while the expression of bcl6b mRNA was significantly decreased after recovery. These results suggest that the exposure of Oryzias latip es to single or combined atrazine and chlorpyrifos had toxic effect, causing significant changes in the activities of antioxidant enzyme (SOD, GSH-PX) and the expression of bcl6b mRNA. The expression ofbcl6b mRNA was contrary to the change trend of antioxidant enzyme levels. After the environmental conditions being improved, the activities of those two enzymes and the expression of bcl6b mRNA could be effectively recovered.

Dynamic monitoring of ecological environment quality in Kunming based on RSEI model.

NONG Lan-ping, WANG Jin-liang

2020, 39(6):  2042-2050. 

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Using remote sensing technology to monitor ecological environment is a good way to quickly acquire the changes of ecological environment. Based on the data of Landsat TM and OLI images, we constructed a model of Remote Sensing Ecological Index (RSEI) with four indicators (greenness, humidity, dryness and heat) by using principal component analysis. This model was used to evaluate the ecological environment quality of Kunming during 2000-2018. The results showed that RSEI can well indicate the quality of regional ecological environment. RSEI was mainly affected by dryness, followed by humidity and greenness, with heat having the least influence. From 2000 to 2018, the five-year average of RSEI in Kunming was 0.51, and the ecological environment quality was in a general state (0.4-0.6). The quality of ecological environment showed a fluctuating trend of “rise-down-rise-down” over time. The quality of ecological environment was better in the western Kunming than in the eastern part, with the best in the southwest corner of Kunming.

Analysis of tourism carbon equilibrium in Taiyuan City from a low-carbon perspective.

CHENG Zhan-hong, WANG Zheng, MA Zi-xing

2020, 39(6):  2051-2060. 

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Low-carbon tourism is an important way to solve the contradiction between tourism development and environmental protection. Carbon equilibrium analysis is an exploratory work in the low-carbon transformation of tourism in the new era, as it has broken through the predicament of previous research, which cannot clearly quantify the pressure of carbon emission reduction. Consequently, carbon equilibrium analysis has become a new academic hotspot. In this study, combined with regional tourism income and GDP, we established models of carbon emission and ecosystem carbon sequestration to estimate the mean annual carbon deficit of tourism in Taiyuan City. From 2010 to 2016, carbon emission of tourism increased from 48.85×10⁷ kg to 66.84×10⁷ kg. Transport, accommodation, shopping, and catering sectors were the main carbon sources. The proportion of tourism transportation and accommodation sectors to carbon emission generally-reduced in the selected period of time, while the proportion of other sectors increased annually, implying the change of tourism consumption structure to some extent. Mean annual carbon sequestration of terrestrial ecosystems in Taiyuan was 122.98×10⁷kg. Forest and farmland were major carbon sink, while grassland and aquatic systems were relatively weak in sequestering carbon. The estimated mean annual carbon deficit of tourism was 34.30×10⁷ kg, with a serious carbon imbalance. Therefore, tourism is a significant carbon source in Taiyuan. Energy saving, emission reduction, and ecological enhancement of carbon sink should be effective ways for future development.

Evaluation of land eco-security in Fenhe River Basin based on matter-element model.

GUO Li-gang, FENG Zhen-zhen, LIU Geng, SHI Ying, WANG Jie, LIN Fei, MA Xiao-hong

2020, 39(6):  2061-2069. 

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Land ecological security, the core of sustainable utilization of land resource, is relevant to human well-being. The study of land ecological security is of great significance to reveal the characteristics of land use security and promote the coordinated regional development of population, resources and environment. Using the “PressureState-Response (PSR)” model, we constructed an evaluation index system of land ecological security in Fenhe River Basin. The index weight was determined by AHP and entropy method, while the matter-element model was used to evaluate land ecological security. In 2006, the land ecological security of Fenhe River Basin was at the state of “transforming to safe status”. In 2012 and 2017, it was at the state of “transforming to moderately safe status”, with overall situation being stable. From 2006 to 2017, landscape fragmentation, per capita water resource and river network density were the main factors restricting land ecological security. In 2017, 15% of the counties (cities/districts) were at the “safe” state, with most of which being concentrated in the upstream area. Land ecological security in the upstream area was generally higher than that in the middle and downstream areas.

A review on the prevalence and features of toxic benthic cyanobacteria in freshwater.

TIAN Xiao-meng, PEI Hai-yan, XU Hang-zhou, ZHANG Yan-fang, WEI Jie-lin

2020, 39(6):  2070-2085. 

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Benthic cyanobacteria are globally distributed in various forms of aquatic systems,including river, lake, wetland, and spring. Due to their concealment and the difficulty of sampling, they have received less attention than their planktonic counterparts. Recently, excessive proliferation of toxic benthic cyanobacteria is increasing. We carried out a literature review on species composition, main factors affecting growth, harmful secondary metabolites, and methods of analysis and risk assessment of toxic benthic cyanobacteria. We reviewed the relationships of main environmental factors (light, temperature, nutrient, substrate, and flow disturbance) during the accumulation of toxic benthic cyanobacteria, and highlighted the importance of the interaction between toxic benthic cyanobacteria and microbial communities within mat habitats. We analyzed the categories of metabolites produced by different toxic species and the influencing factors of their production. Furthermore, we compared current methods for qualitative and quantitative analysis of toxic benthic cyanobacteria and their limitations, and recommended future directions to optimize the prediction and detection of highly concentrated toxic ones. This review provides reference for studies on excessive proliferation mechanisms and effective control methods for toxic benthic cyanobacteria.

A review on the assessment methods of supply and demand of ecosystem services.

GUO Chao-qiong, XU Xi-bao, SHU Qiang

2020, 39(6):  2086-2096. 

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The assessment of supply and demand of ecosystem services can help identify regional equilibrium, ecological trade-off, management, and compensation. It is one of the key issues in ecosystem service studies. We collected literature on the assessment methods of ecosystem services. Based on the existing studies, the assessment methods were classified into four categories: ecological model, value assessment method, participation method, and empirical statistical model. These four types of methods are mainly used to assess service supply, but seldom be used in studies on demand assessment. Ecological model and value assessment method are applicable to a wide range of scales, from the local scale to global scale, while the participation method and empirical statistical model are usually used at small and medium scales. Compared with the other three types of methods, ecological model requires more types of data, higher requirements ofinput data, with higher evaluation accuracy. Ecological model has more advantages in spatial scale, data acquisition, and applications. Finally, we suggested that three aspects deserved more attentions in the future, including: building a diverse and standard supply-demand indicator system, strengthening the accuracy of ecosystem service assessment, and strengthening the integration and development of different models.

Life cycle carbon emissions and cost assessment of CO₂ mineralization and utilization technology by means of blast furnace slag.

MA Ming-jing, XI Feng-ming, WANG Jiao-yue, YIN Yan, CHANG Sha-sha

2020, 39(6):  2097-2105. 

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The mineralization and utilization technology of CO₂ by means of blast furnace slag (BFS) is a route of CO₂ capture, utilization and storage (CCUS) with both environmental and economic benefits, which can reduce CO₂ emissions and realize the utilization for solid waste. This technology can achieve the “controlling waste by waste” purpose. Here, life cycle assessment method was used to simulate four CCUS scenarios by combining different CO₂ capture technologies (post-combustion capture system and oxy-combustion capture system) with two novel CO₂ mineralization processes, with the consumption of 1 t BFS as a research unit. Carbon emissions and cost under four CCUS scenarios from CO₂ capture, transportation and storage to product production were systematically calculated. The results showed that three scenarios can meet the requirements of CO₂ emissions reduction, including co-production of aluminum-rich products by mineralization under postcombustion capture system,  co-production of ammonium aluminum by mineralization under oxy-combustion capture system, and  co-production of aluminum-rich products by mineralization under oxy-combustion capture system. Their carbon storage efficiency was 29%, 32.7%, and 76.2%, respectively. Furthermore, the life cycle cost of those three scenarios was 544, 1384, and 530 CNY, respectively. Among them, scenario of co-production of ammonium aluminum by mineralization under oxycombustion capture system can store a large amount of CO₂ and obtain the largest profit (about 297 CNY), with a broad prospect of industrial application.

Redevelopment mode and strategy of mining wasteland in an ecosystem service perspective.

DAI Pei-chao, ZHANG Shao-liang, GONG Yun-long, HOU Hu-ping

2020, 39(6):  2106-2114. 

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The redevelopment of mining wasteland, as one of the effective ways to exploit stocking land, is important to the improvement of mining environment and the economic transformation of mining area. Given the destroyed nature of mining wasteland, the choice of redevelopment mode is crucial to ecological changes in the mining area. To ensure the redevelopment of mining wasteland, and realize the vision of ecological restoration, optimized layout of land use, and harmonious coexistence between human and nature, we constructed a theoretical framework for the redevelopment of mining wasteland with an ecosystem service perspective. Under this framework, the redevelopment target, model, and strategy were addressed by the methods of literature analysis, theoretical analysis, and case study. We concluded that: (1) The ultimate goal of mining wasteland’s redevelopment should be the improvement of socialecosystem resilience; (2) Five redevelopment modes, including supplyservice-oriented mode and support service-priority mode, are proposed following the theory of ecosystem services, with the multi-service synergy mode as the ideal one for redevelopment; (3) The direction of the redevelopment of mining wasteland depends on the trade-off and synergy among ecosystem services. In conclusion, from the perspective of ecosystem services, the redevelopment of mining wasteland should take a comprehensive measure for remediation and choose appropriate development mode suitable for specific site, with the goal of increasing total value of ecosystem services, improving social-ecosystem resilience, and promoting regional coordination and sustainable development.

Analysis of suitable distribution areas of Fargesia denudata in Baishuijiang National Nature Reserve using MaxEnt model and ArcGIS.

HU Shu-ping, HE Li-wen

2020, 39(6):  2115-2122. 

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Fargesia denudata is one of the primary edible bamboo species for giant panda and the most widely distributed species of genus Fargesia in Baishuijiang National Nature Reserve, Gansu Province. Understanding the geographical distribution of F. denudata will facilitate the conservation of wild giant panda. Through field investigation and data sorting, 73 effective distribution recordsofF. denudata were obtained. A total of 45 environmental variables with respect to climate, soil, topography, and evapotranspiration were analyzed by multicollinearity. After eliminating environmental factors with low contribution rates, seven climate variables, three soil variables, two topography variables, and two evapotranspiration variables were chosen as model inputs. MaxEnt was used to simulate geographical distribution of F. denudata and the contributions of different variables. Finally, ArcGIS was used to classify the grades of suitable distribution and extract environmental characteristics. The AUC value of ROC curve was 0.932, suggesting high reliability and accuracy of the simulation. Results of Jackknife test showed that minimum temperature of coldest month, altitude, standard deviation of seasonal variation of temperature, precipitation of wettest month, and temperature annual range affected the distribution of F. denudata. Distribution of suitable area of F. denudata was concentrated in the western part of the reserve. The suitable area was 584.76 km², accounting for 31.13% of the total area of the reserve. The most suitable area was 103.15 km², with minimum temperature of coldest month from -15 ℃ to -9 ℃ and altitude range of 2148-3468 m. The MaxEnt can well simulate the geographical distribution of F. denudata and evaluate the importance of environmental variables. Our results could provide reference for F. denudataprotection of wild giant panda’s main food resources in the reserve.