Table of Content

10 June 2022, Volume 41 Issue 6

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Effects of species interactions on tree growth and survival of mixed broadleaved Korean pine forest on Changbai Mountain.

CHU Kuo, HE Hai-yan, CHEN Qing-ying, CAI Feng-kun, SONG Guang, YE Ji

2022, 41(6):  1050-1055.  doi:10.13292/j.1000-4890.202206.025

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Elucidating species interaction is a core issue of ecological research. The interaction among different tree species is a key factor affecting forest community assembly. The neighborhood effect is a prominent manifestation of the interaction among tree species. As an quantiative index of the neighborhood effect, neighborhood density affects the growth and survival of individual trees within a certain range, and such effect varies among different tree species. In this study, based on data of two investigations in a 25hm² broadleaf Korean pine forest dynamic monitoring plot, we explored the role of tree species interaction in influencing community dynamics by analyzing its impacts on tree growth and survival. We found that the neighborhood density had a stronger effect on tree growth than tree survival in the broadleaved Korean pine forest, with primarily negative effect. There was a significant negative correlation between the growth and the neighborhood density ofAcer mandshuricum, Acer mono, Prunus padus, Corylus mandshurica,andSyringa reticulata. By dividing the neighborhood composition into conspecific and heterospecific neighbors, we found a significant correlation between tree growth and densities of both neighborhood types, and that the correlation with the heterospecific neighborhood density was mainly negative. There was a significant negative correlation between tree survival and conspecific neighborhood density, but a weak correlation between tree survival and heterospecific neighborhood density. The negative effect of the conspecific neighborhood density was mainly concentrated in Acer mono, Acer pseudo sieboldianum, Tilia amurensis, and Acer barbinerve. In conclusion, species interaction is an important factor affecting tree growth and survival in Changbai Mountain broadleaved Korean pine forest, with species-specific direction of interaction. Our results uncovered the effects of species interaction on tree growth and survival in the broadleaved Korean pine forest, which could facilitate biodiversity conservation in temperate forests.

Effects of thinning and fertilization on GHGs emissions in Chinese fir plantation soil.

DING Chi, LEI Mei, GAN Zi-ying, WANG Hao, YAN Qiang, QIU Qing-yan, HU Ya-lin

2022, 41(6):  1056-1065.  doi:10.13292/j.1000-4890.202205.002

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Understanding the effects of thinning intensity and fertilizer application on soil greenhouse gas emissions of forest plantations is important to accurate assessment of the capacity of greenhouse gas emissions from plantation soils. In this study, three levels of thinning intensity (mild, moderate, and severe) and two levels of fertilizer application (no fertilization and fertilization) were carried out in a subtropical Chinese fir (Cunninghamia lanceolata) plantation in China to investigate the effects of thinning intensity and fertilization  on soil CO₂, CH₄ and N₂O emissions and global warming potentials (GWPs). Soil physicochemical properties were measured to clarify the main factors that regulating soil greenhouse gas emissions. The results showed that mild thinning intensity significantly increased soil CO₂ emissions and CH₄ absorption compared with moderate thinning intensity. Fertilization together with mild thinning intensity significantly increased soil temperature sensitivity (Q₁₀). Fertilization combined with moderate thinning intensity significantly decreased soil N₂O emission, while fertilization combined with severe thinning intensity significantly increased soil CO₂ and N₂O emissions and CH₄ absorption. From the perspective of GWPs, the combined treatment of severe thinning intensity and fertilization had the largest GWPs, followed by mild and moderate thinning intensity. Throughout the observation period, Chinese fir plantation soil was CO₂ and N₂O source, but CH₄ sink. Soil moisture was the dominant factor regulating soil CO₂ emission and CH₄ absorption, followed by soil available N. Soil N₂O emissions were controlled by soil temperature. The results indicated that different thinning intensities and fertilization treatments had significant effects on soil greenhouse gas emissions and GWPs of Chinese fir plantations by changing soil moisture, temperature and N availability. Moderate thinning had better potential in reducing soil greenhouse gas emissions.

Effects of gap size on soil phosphorus fractions in Platycladus orientalis plantation.

PAN Yu-yang, SUN Xiao-dan, FEI Fei, ZHAO Jia-hao, WANG Ya-ru, LI Hui-zhi, SUN Liang, GUAN Qing-wei

2022, 41(6):  1066-1071.  doi:10.13292/j.1000-4890.202206.010

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Phosphorus is a limiting nutrient in forest ecosystems. Little attention has been paid to the effects of gap size on soil phosphorus fractions. In particular, the variation characteristics of phosphorus fractions at different positions in different size gaps are not clear. In this study, we carried out an experiment in a 50-year-old Platycladus orientalisplantation in Zhaotuan Forest Farm, Xuzhou, after opening forest gaps for four years. We examined the changes of soil phosphorus fractions in different positions (D₁ in the gap center, D₂ in the edge of the gap, D₃ in the understory, D₄ in the understory) under control, small, medium and large gaps (radius R was 4, 8 and 12 m, respectively). The results showed that: (1) The effects of different gap sizes on the concentrations of total phosphorus, NaHCO₃-Po, NaOH-Pi, NaOH-Po, HCl-Pi and Residual-P were in the order of medium gap > large and small gaps. The effects of gap size on the NaHCO₃-Pi concentration were in the order of the medium and large gaps > small gap, and the effects on the H₂O-Pi concentration were in the order of small gap > big gap > medium gap. Soil NaHCO₃-Po concentration significantly differed among positions of forest gap (P<0.05), and showed a single peak trend of “low-high-low” at different positions of small and medium gap. (2) Compared with the control, soil pH decreased and water content increased after four years of gap formation. Soil total nitrogen and organic carbon concentration increased in the small gap, but decreased in the medium and large gap. The effects of different gap sizes on microbial biomass phosphorus and alkaline phosphatase activity were in the order of medium gap > large and small gap. (3) Soil water content, organic carbon, microbial biomass phosphorus and alkaline phosphatase activity were important factors affecting soil phosphorus fractions. In conclusion, the medium gap is beneficial to improve soil phosphorus availability. Our results can provide a scientific basis for the determination of reasonable gap size of P. orientalis plantations, and for improving soil phosphorus deficiency, forest productivity, and ecosystem stability.

Suitable environmental factors for two climbing bamboo species in tropical lowland rain forest.

XU Rui-jing, LIU Guang-lu, HU Xuan, PENG Chao

2022, 41(6):  1072-1078.  doi:10.13292/j.1000-4890.202206.008

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To explore the key environmental factors suitable for the distribution of climbing bamboo in tropical lowland rain forests, we examined 32 environmental factors including soil physicochemical properties, stand structure, site conditions and the relationships between the distribution of two climbing bamboo species (Dinochloa orenuda and Bonia levigata) and dominant species in a tropical lowland rain forest of Ganshiling, Hainan Island, using the methods of plot investigation, redundancy analysis and detrended correspondence analysis. Results showed that: (1) The cluster densities of D. orenuda and B. levigata were (258.75±99.10) and (81.25±78.64) clumps·hm^-2. The average plant individuals per cluster were (19.56±8.34) and (12.00±2.65). The plant individial density were (2027.50±547.69) and (558.75±521.19) plants·hm^-2. The mean DBH were (20.45±0.55) and (6.18±0.66) mm, respectively. (2) The environmental factors influencing the distribution of the two climbing bamboo species were in the order of: slope position > litter thickness > rock bareness > soil bulk density > slope > field water-holding capacity. The cluster densities of two climbing bamboo species were positively affected by minimum soil water-holding capacity and slope. Bulk density was the limiting factor for the distribution of two climbing bamboo species. Rock bareness and litter thickness were the key factors promoting the number of bamboo clumps in D. orenuda and B. levigata, respectively. (3) D. orenuda and B. levigata had a relatively distant relationship with dominant species in the community. D. orenuda tended to distribute in the tropical rain forest with large tree species, while B. levigata tended to distribute in the rain forest with more small trees. The distribution of D. orenuda and B. levigata in Ganshiling was mainly affected by topography, soil physical properties, and litter thickness. The two climbing bamboo species tended to grow in the valley with low soil bulk density, high field water-holding capacity and steep downhill. D. orenuda preferred the area with large litter thickness, and B. levigata preferred the area with large rock bareness and low litter thickness.

The spatiotemporal variation and influencing factors of vegetation carbon and water use efficiency in the Mongolian Plateau.

YIN Chao-hua, LUO Min, MENG Fan-hao, SA Chu-la, BAO Yu-hai

2022, 41(6):  1079-1089.  doi:10.13292/j.1000-4890.202205.008

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The carbon and water use efficiency of vegetation are the important variables reflecting ecosystem carbon-water cycle. Analyzing their dynamics and driving factors is of great significance for ecosystem sustainable development in the arid and semi-arid Mongolian Plateau. Using trend analysis, partial correlation analysis, and residual analysis, we analyzed the spatiotemporal variations of vegetation carbon use efficiency (CUE) and water use efficiency (WUE) of the Mongolian Plateau from 2000 to 2019, and examined their relationships with precipitation, temperature, and human activities. The CUE of vegetation in the Mongolian Plateau showed a significant increasing trend during  2000-2019, with a rate of 0.2%·a^-1, while the WUE showed a non-significant decreasing trend. The CUE increased significantly in all ecological divisions except broad-leaved forests, mixed forests, and alpine meadows, while WUE showed an increasing trend only in coniferous forests and desert steppe. The CUE and WUE were positively correlated with precipitation and negatively correlated with temperature in most of the Mongolian Plateau (>60%). Affected by human activities, 62.9% of the plateau area suffered a significantly increased CUE residual, while only 10.6% of the study area showed a significant increasing trend in WUE residual. Our results provide vital information for understanding the impacts of climate change and human activities on carbon-water cycling in the Mongolian Plateau.

Effects of precipitation on the release of carbon, nitrogen, and phosphorus from decomposing litter of four plant species in a desert steppe.

HAN Cui, KANG Yang-mei, YU Hai-long, LI Chun-huan, HUANG Ju-ying

2022, 41(6):  1090-1100.  doi:10.13292/j.1000-4890.202206.021

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 Exploring the impacts of precipitation on litter decomposition of plant species will help to deeply understand the biogeochemical cycle of grassland ecosystems under global changes. We carried out a 480-day decomposition experiment based on a field experiment of precipitation change in a desert steppe of Ningxia conducted in 2014. The element release and ecological stoichiometry of four plant species litters were examined, and their relationships with soil element supply level were analyzed. The results showed that the C release from the litters of the four species was slow. Except Artemisia scoparia, the C release rates even did not reach 50% after 360 days of decomposition in most cases. The release of N and P from litters of the four species was faster in the early stage than that in the late stage. The release rates of N and P exceeded 50% after 180 days of decomposition in most cases. The 50% reduction in precipitation significantly decreased the cumulative release of the three elements in the litters of A. scoparia and the cumulative release of P in the litters of Pennisetum centrasiaticum (P<0.05). The increasing precipitation showed opposite effects, but the 50% increase in precipitation significantly reduced the cumulative release of C and N in the litters of A. scoparia (P<0.05). Compared with the 30% reduction in precipitation, the 50% reduction, 30% increase, and 50% increase in precipitation changed litter C∶N∶P ecological stoichiometry of the four species.  However, their impacts were speciesspecific and without clear trends. The cumulative release of P in the litters of A. scoparia and Astragalus melilotoides were significantly positively correlated with soil total P concentration (P<0.05), indicating that the P release from the litters of A. melilotoides and A. scoparia is helpful for soil P accumulation.

Effects of no-tillage, mulching, and organic fertilizer application on the diversity of arbuscular mycorrhizal fungi in winter wheat field.

LIU Wen-juan, MA Kun, WANG Bing-bing, HE Ya-ling, JIANG Qin-fang, MI Yang

2022, 41(6):  1101-1108.  doi:10.13292/j.1000-4890.202206.024

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Our objective was to investigate the effects of agricultural management on the structure and diversity of soil arbuscular mycorrhizal fungi (AMF) communities. An experiment was conducted in a mountainous area of south Ningxia with four treatments: no-tillage mulching without organic fertilizer application (NC), no-tillage mulching with organic fertilizer application (NF), conventional tillage without organic fertilizer application (TC), and conventional tillage with organic fertilizer application (TF). Illumina MiSeq sequencing technology was used to analyze the impacts of conservation tillage measures on the structure and diversity of soil AMF communities. The results showed that: (1) Tillage significantly affected soil available N and available K contents. Compared with no fertilization, organic fertilizer application significantly altered soil pH, available P, available K and organic matter. Soil available K and organic matter contents of NF treatment were significantly increased. (2) In all the 16 soil samples, 1 phylum, 3 classes, 4 orders, 5 families, 7 genera of AMF were identified. The dominant genera wereGlomus, Claroideoglomus, andParaglomus. Organic fertilizer application decreased the relative abundance of dominant genera. (3) Both tillage and organic fertilizer application did not affect the species richness of soil AMF. Tillage significantly affected evenness (Pielou_e) and diversity (Shannon and Simpson indices) of soil AMF. Notillage mulching without organic fertilizer application (NC) increased evenness (Pielou_e) and diversity index (Shannon index) of soil AMF. Both fertilization and tillage affected the composition of soil AMF community, with the effect of tillage on the diversity of soil AMF community being more obvious. (4) The results of nonmetric multidimensional scaling and redundancy analysis showed that total nitrogen and pH were the dominant variables affecting AMF community composition, but were not the key environmental variable driving AMF community change. Therefore, conservation agricultural management practices of no-tillage mulching and organic fertilizer application could improve soil physicochemical properties and increase soil AMF community diversity in the mountainous area of south Ningxia.

Effects of water level change and normal moisture after waterlogging on the growth and physiology of Artemisia selengensis.

LI Xiao, CAO Yun, XIE Qin-zhao, YAO Xiao-chen, TANG Si-wen, FENG Kai-pin

2022, 41(6):  1109-1120.  doi:10.13292/j.1000-4890.202206.003

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Plant survival in cyclically changing water levels and the recovery after water recession reflect their adaptability to flooding. To better understand the tolerance to flooding stress of Artemisia selengensis, a typical wetland plant in Poyang Lake, we examined the morphological and physiological responses of A. selengensis to three kinds of water environment and after water withdrawal and recovery. The double-pot method was adopted, with three water levels (rising, falling and stabilizing) being set up. In the rising water level group, six water levels were set up, which all initially increased from 0 cm, with an increasing intensity of 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 cm·d^-1, respectively, with final water levels being 5, 10, 15, 20, 25, and 30 cm respectively after 50 days. In the descending water level group, six water levels were set up, the water levels were decreased from 5, 10, 15, 20, 25 and 30 cm, with a decreasing intensity of 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 cm·d^-1 respectively, and all the final water levels were 0 cm after 50 days. In the stable water level group, six water levels were set up, which were 5, 10, 15, 20, 25 and 30 cm respectively, and the water levels remained constant. A control group with the water level of 0 cm was set up (the water level in the pot just submerged the soil surface). The treatment time of water level fluctuation was 50 days and the normal moisture after waterlogging time was 10 days, resulting in a total of 60 days. Results showed that: (1) In the three water level environment types, when water level was lower than 15 cm, the increases of plant height and the number of leaves showed a gradual upward trend. However, when the water level was higher than 15 cm, the growth rate of plant height and the number of leaves decreased. In the rising water level group, plant height and the number of leaves with the treatment intensity of 0.1-0.3 cm·d^-1 were significantly higher than the control group. (2) In the rising water level, the treatment intensity of 0.3 cm·d^-1 was within the tolerance range of A. selengensis to waterlogging. When the treatment intensity was less than 0.3 cm·d^-1, the change of antioxidant enzyme activity was obviously different from that of more than 0.3 cm·d^-1. Affected by the initial water level, the activities of superoxide dismutase and catalase of A. selengensis in the falling water level reached the maximum at 10-20 days. In the stable water level, when the waterlogging depth was 10 and 15 cm, the antioxidant enzyme activity increased continuously. The activities of superoxide dismutase and catalase decreased with increasing waterlogging time and stress intensity, whereas peroxidase activity showed an increasing trend. (3) Among the three types of water level environment, the superoxide anion production rates and malondialdehyde content did not differ from that in the control group under low intensity stress (P>0.05), which were correlated to the antioxidant enzyme activity in the early stage of the experiment. The superoxide anion production rates and malondialdehyde content in high intensity treatment group increased with increasing waterlogging depth and duration, and were significantly higher than those in control group. (4) In normal moisture condition after waterlogging, all indices of low-intensity treatment group recovered quickly and had no significant difference with that of the control group (P>0.05). The indices of high intensity treatment group recovered slowly or not completely. Therefore, A. selengensis is suitable for ecological restoration and reconstruction in the short-term and in a low-intensity-alteration water environment.

Effects of multiple abiotic factors on sexual recruitment of Typha orientalis population in the riparian zone of Three Gorges Reservoir.

HU Ke, YAN Guang-rong, TANG An-jun

2022, 41(6):  1121-1127.  doi:10.13292/j.1000-4890.202205.003

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The timing, duration and frequency of inundation greatly affect ecological conditions, wetland plant regeneration and biodiversity in the water-level-fluctuating zone. Based on the spatiotemporal variation of hydrology in the water-level-fluctuating zone of the Three Gorges Reservoir, we analyzed the effects of multiple abiotic factors such as inundation, temperature, light, and germination substrate on the population sexual recruitment of Typha orientalisto reveal the effects of abiotic factors on sexual recruitment. The results showed that freshly-collected ripe seeds of T. orientalisis were light-required, with obvious preference for temperature and substrate. In the lake water, seed germination rate decreased with increasing water depth. When water depth was 2 m, germination rate decreased to 4.5%. In the simulated flooding trail, seedling survival rates were 21% and zero after 56 and 60 days in full flooding, respectively. However, the seedlings grew well under non-flooded and semi-flooded conditions. It is concluded that severe flooding stress is the direct cause of germination inhibition and seedling death of Typha orientalis. The seeds would germinate well under appropriate combination of light, temperature and germination substrate. The failure of sexual regeneration of T. orientalisis population is driven by a variety of abiotic factors in the water-level fluctuating zone of the Three Gorges Reservoir.

Effect of iron-rich farmland drainage on phosphorus adsorption and release in sediments of Xiaoxingkai Lake.

JIA Xue-ying, TIAN Zhi-jie, ZHANG Dong-jie, JIANG Ming, WANG Li-hong

2022, 41(6):  1128-1134.  doi:10.13292/j.1000-4890.202206.023

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To explore the impacts of ironrich farmland drainage on the eutrophication of lakes in Sanjiang Plain, we analyzed the forms, contents, adsorption and release parameters of phosphorus in sediments and the role of main environmental factors in Xiaoxingkai Lake. Affected by farmland drainage, the eutrophication of Xiaoxingkai Lake was at moderate level. The Dongbeipaozi, which had poor water conservancy connectivity and surrounded by rice fields, was heavily polluted. The phosphorus adsorption capacity (Q_max) of sediments ranged from 29.41 to 125.00 mg·kg^-1. Phosphorus in overlying water could be easily adsorbed by sediments, and the average release rate was only 11.73%. The phosphorus adsorption was affected by environmental factors and physicochemical characteristics of sediments. Among the environmental factors, Fe/P and temperature had a significant promotion effect on phosphorus adsorption, and pH in the range of 5-9 had limited effect on phosphorus adsorption of sediments. The particle size composition and Fe-P content in inorganic phosphorus had significant effects on the phosphorus adsorption of sediments. Our results provide basic data for revealing the degree of lake eutrophication and the risk of endogenous phosphorus release under the influence of iron-rich farmland drainage.

 

Characteristics of aquatic macroinvertebrate assemblages in abandoned fishponds.

ZHANG Dan, ZHANG Guan-xiong, WANG Ke-hong, WANG Fang, LIU Shuang-shuang, PAN Yuan-zhen, YUAN Xing-zhong

2022, 41(6):  1135-1142.  doi:10.13292/j.1000-4890.202205.005

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With the development of agricultural activities, some fishponds once used for agriculture have been abandoned, which are habitats suitable for aquatic organisms. We investigated habitat structure, water quality and aquatic macroinvertebrate community of four abandoned ponds and four fishponds (control groups) in Liangping District of Chongqing, to understand the characteristics of the special habitat and community structure of the assemblages. The results showed that the aquaculture of the fishponds was higher in water nutrient concentration and lower in the coverage of aquatic macrophytes, thus reducing species richness and density of macroinvertebrates. The abandoned ponds were characterized by lower nutrient concentration, less predation and competition pressure, more abundant aquatic macrophytes, supporting more species richness and density of aquatic macroinvertebrates. Thirty-nine species of aquatic macroinvertebrates were recorded in this study, including 33 species in the abandoned ponds and 19 species in the fishponds. The assemblages were dominated by aquatic insects, followed by Gastropoda. Among the aquatic macroinvertebrates, Gastropoda and Odonata had a positive correlation with the coverage of macrophytes but a negative correlation with nutrient concentration. The results can provide scientific basis for assessing regional biodiversity.

Seasonal variation in microhabitat selection of Buff-throated Partridge (Tetraophasiszechenyii).

WANG Bin, ZHU Bo-wei, XU Yu, YANG Nan, ZHAO Cheng, DOU Liang, RAN Jiang-hong

2022, 41(6):  1143-1148.  doi:10.13292/j.1000-4890.202205.022

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Habitat selection is essential for the survival and reproduction of animals. Studying species habitat selection in different seasons not only benefits thorough understanding of its ecological habits and resource requirements, but also provides fundamental information for conservation. Buff-throated Partridge (Tetraophasis szechenyii) is a typical alpine bird species endemic to China and a firstclass national protected wildlife species. Yet, variation in microhabitat selection of Buff-throated Partridge has been poorly understood. During 2014 and 2015, we investigated its microhabitat selection in breeding season (April-July) and nonbreeding season (August-March) in Gexigou National Nature Reserve, Sichuan Province. The results showed that the species preferred microhabitat with low tree coverage and high grass height during breeding season, but selected microhabitat with high proportion of bare soil and low tree coverage during non-breeding season. They select microhabitat that simultaneously meet the demands of food resource and conditions for rearing chicken during breeding season, and use microhabitat with high food accessibility and concealment to overcome food shortage, reduce predation risk, and preserve body heat during non-breeding season. The seasonal variation in microhabitat selection of Buffthroated Partridge is related to resource requirements in different periods of life history, indicating its adaption to environmental change. For effective species conservation, we recommend restriction of free-ranging yak grazing in the habitat of Buff-throated Partridge.

The distribution of high temperature and high humidity disasters for facility tomato in Fujian Province.

YANG Liu, ZHANG Qi, YANG Zai-qiang, CHEN Jia-jin, HUANG Chuan-rong

2022, 41(6):  1149-1155.  doi:10.13292/j.1000-4890.202206.022

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Based on the meteorological data of Fuqing Station in Fujian Province and the microclimate data of the facility greenhouses from 2017 to 2019, we used multiple linear regression, BP neural network and extreme learning machine (ELM) to construct the simulation models of the facility microclimate. The indoor microclimate data were retrieved from the meteorological data of 18 meteorological stations from 1990 to 2019. Combined with the high temperature and high humidity grade index of facility tomato, we examined the spatial and temporal pattern of high temperature and high humidity of facility tomato in Fujian Province. The results showed that the maximum and minimum indoor air temperatures were best simulated by multiple linear regression model, with RMSE being 2.19 and 1.20 ℃, and R² being 0.87 and 0.96, respectively. BP neural network method was the best one to simulate the maximum relative humidity, with RMSE being 3.77% and R² being 0.65. Combined with facility crop disaster indicators, the frequency of level-2 high temperature and high humidity disasters in the northern and central regions of Fujian Province significantly increased year by year, while the frequency of level-3 disasters in the central region decreased year by year. The probability of level-2 disasters was high across all regions, the probability of level-1 disasters was small in the north and central regions, and the probability of level-3 disasters was small in the south. The meteorological disaster level of facility tomato was high during May to July, and distributed in the northwest of Fujian. The disaster level was the lowest from August to October, with level 2 in most of the whole province and level- 1 only in some coastal areas. The results provide scientific basis for meteorological layout and environmental regulation of facility tomato.

Impact of land use change on carbon storage in the Dongting Lake Eco-economic Zone.

LI Jiao, WANG Jie, LI Lang, ZHOU Cui-yan, NIU Qian, ZHANG Can-ming

2022, 41(6):  1156-1165.  doi:10.13292/j.1000-4890.202206.026

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Carbon sink in terrestrial ecosystem plays an important role in global carbon cycle and climate change, while land is an important factor affecting the carbon storage of terrestrial ecosystems. In this study, using the ArcGIS software and InVEST model, we analyzed land use changes in the Dongting Lake Eco-economic Zoneand the impact of such changes on carbon storage based on the data in 2005, 2010, and 2015. The results showed that during the period 2005-2015, the land use of the study area had changed greatly. The areas of other woodland, reservoir/pond, urban land, other construction land and bare land increased, while those of paddy field, dry land, forest land, spinney, open woodland and lake decreased. Driven by the land use change, carbon storage of the Dongting Lake Eco-economic Zone showed an general downward trend from 2005 to 2015, from 11.67×10⁸ t in 2005 to 11.52×10⁸ t in 2015, with a reduction of 1.28%. According to the analysis of carbon stock transfer matrix, the main reasons for the reduction of regional carbon storage were the decrease of farmland and forest land as well as the increase of construction land.

Effects of land use conversion around a lead-zinc slag heap on soil extracellular enzyme activities.

WANG Guang-hao, KONG Xing-jie, SUN Cai-li, WU Pan

2022, 41(6):  1166-1172.  doi:10.13292/j.1000-4890.202206.028

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In this study, seven typical land use types around a historical lead-zinc slag heap were selected as the research objects, including sloped farmland, terraced corn field, terraced radish field, terraced buckwheat field, Yunnan pine forest, Cryptomeria fortunei forest, and secondary forest. The soil contents of nutrients and heavy metals and the activities of six extracellular enzymes (β-1,4-glucosidase, cellobiohydrolase, β-1,4-xylosidase, β-1,4-N acetylglucosaminidase, L-leucine aminopeptidase, and acid phosphatase) were examined using space fortime substitution. We analyzed the relationship between environmental factors and extracellular enzyme activities. Theresults showed that soil nutrients (organic carbon, total nitrogen, nitrate nitrogen, ammonium nitrogen) increased after sloped farmland was converted to other land use types. The activities of six extracellular enzymes exhibited a similar pattern, which were higher in secondary forest, Yunnan pine land, and C. fortunei forest than those in terraced radish field and lowest in sloped farmland. The conversion of sloped farmland to secondary forest, terraced radish field or terraced corn field could reduce soil Zn content. Soil Cu content significantly decreased when sloped farmland was converted to other land use types, except for the terraced corn land and Yunnan pine forest. Compared with heavy metal pollution, soil nutrient (organic carbon, total nitrogen, and ammonium nitrogen) contents showed a greater influence on soil extracellular enzyme activities, being the major factors driving changes in enzyme activities during land use conversion.

Characteristics of blue-green infrastructure and its relationship with thermal environment in blocks based on morphological spatial pattern analysis (MSPA).

SU Wang-xin, ZHANG Liu-kuan, CHANG Qing

2022, 41(6):  1173-1181.  doi:10.13292/j.1000-4890.202205.015

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Urban green-blue infrastructure (GBI) in blocks plays an important role in adapting to climate change by solving urban thermal environment and improving thermal comfort. Based on high resolution images of Three Hills and Five Gardens Area in Beijing, morphological spatial pattern analysis (MSPA) was used to quantify the pattern of urban GBI. GBI types included branch, bridge, core, edge, islet, loop, and perforation. We analyzed the correlation between GBI’s composition and structure and land surface temperature, and GBI’s thermal mitigation ability and its influencing factors. In Three Hills and Five Gardens Area, the area ratio of GBI was 60.61%, while the correlation between mean surface temperature (T_m) and GBI’s area ratio was significantly negative. The correlation between T_m and ratio of trees was greater than that with water body or grassland. The relevance was higher between T_m and the ratio of core area than with perforation area, edge area, loop area, bridge area and branch area in turn. Thermal mitigation of GBI was significantly affected by its spatial pattern. In the blocks with core area ratio of GBI over 10%, T_m was negatively correlated with the proportion of core area and perforation area, but not with that of tree, grassland, and water. In the blocks with core area ratio of GBI between 1% and 10%, T_m was negatively correlated with trees occupying area, loop area, bridge area and branch area. In the blocks with core area ratio of less than 1%, T_m was negatively correlated with edge area. In addition to taking green space cover types into consideration, the planning and design of GBI in future blocks should be closely combined with the characteristics of GBI layout, which can be implemented by the following measures: enlarging the scale (increasing the width of peripheral edge area around existing GBI patches), enhancing connectivity (connecting existing GBI patches to construct blue-green corridor), optimizing the configuration of activity fields (appropriately increasing activity fields within the core area), in order to form the nature-based thermal mitigation solutions for blocks. The results can enhance the understanding of relationships between GBI pattern and thermal mitigation characteristics in urban blocks, and provide reference for the mitigation of heat island effect and thermal comfort improvement at urban block scale.

Factors influencing wildlife conservation awareness of indigenous people in Leigongshan National Nature Reserve, Guizhou Province.

SHENG Shang, ZHU Yun, ZHENG Jin-feng, LIU Yu, YU Yong-fu, LI Yang, ZHANG Kai, XU Yu

2022, 41(6):  1182-1187.  doi:10.13292/j.1000-4890.202205.011

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Traditional indigenous culture has important contributions to biodiversity conservation. To explore the factors affecting wildlife conservation awareness of the indigenous people, we used a semi-structured interview method to investigate age, education level, income level, traditional cultural belief, and conservation awareness (including conservation knowledge, and conservation attitude and behavior) of indigenous people in seven communities living in Leigongshan National Nature Reserve in Guizhou Province, China, between 2018 and 2019. We collected a total of 72 valid questionnaires. The results showed that conservation knowledge of indigenous people mainly depended on their education level. There were no significant relationships of conservation knowledge with age, income level, and traditional cultural belief. Conservation attitude and behavior of indigenous people was not significantly affected by their ages, traditional cultural belief or conservation knowledge, but income level could partly predict the variation in conservation attitude and behavior. The results suggested that education level and income level were the most important factors affecting the conservation awareness of indigenous people. However, the conservation knowledge of indigenous people would not be well transformed into conservation behavior. To promote the effectiveness of nature reserve management, we recommend that managers should promote the cultural and educational level of indigenous people, carry out various propaganda campaigns, encourage the inheritance and innovation of excellent traditional culture, and support sustainable economic development, to mobilize indigenous people to engage in conservation.

Analysis on the ecological security of the typical area in the eastern Qinghai-Tibet Plateau based on landscape pattern.

FENG Zhao-hui, LI Xuan-jin, HU Jian, WANG Ling-qing

2022, 41(6):  1188-1196.  doi:10.13292/j.1000-4890.202206.002

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The eastern Qinghai-Tibet Plateau is an ecologically fragile region. Studies on the ecological security of landscape pattern in this region are helpful for promoting the sustainable development of the ecosystems and improving the stability of the Qinghai-Tibet Plateau ecosystem. In this study, the land use data of 2000, 2005, 2010, and 2015 in eastern Qinghai-Tibet Plateau were used to analyze the ecological security change based on landscape pattern. The remote sensing images were interpreted and classified by means of remote sensing technology, and the land use change was analyzed. Furthermore, the spatiotemporal variations of landscape pattern were analyzed by constructing landscape disturbance index and landscape security index. The results showed that: (1) Water body, grassland, urban and rural area, industrial and mining area, and residential area in research region showed an increasing trend, while woodland, cropland and unused land showed a decreasing trend. (2) Grassland and woodland were the dominant landscape, while urban and rural area, industrial and mining area, and residential area had higher interference, fragmentation and separation degrees. The ecological security of unused land, cropland and woodland decreased, while that of urban and rural area, industrial and mining area, residential area and waterbody increased. (3) Cropland, grassland, waterbody, urban and rural area, industrial and mining area, residential area, and unused land had always stayed in the heavy warning level, while woodland was at a relatively safe level. The overall ecological security in eastern QinghaiTibet Plateau rose first and then fell slightly, indicating that the ecological environment in this region was gradually improved and then slightly disturbed. Measures improving the ecological environment should be taken to further enhance the ecological security.

An assessment on the coordinated development of ecology, economy and society in Gansu section of Qilian Mountain National Park.

GAO Yan, FENG Qi, LI Zong-xing

2022, 41(6):  1197-1204.  doi:10.13292/j.1000-4890.202206.018

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Based on the coupling coordination model, we constructed an evaluation index system of three subsystems including ecology, economy, and society in the Gansu section of Qilian Mountain National Park. The evaluation indices were selected according to the respective development characteristics of the three subsystems, and the statistical data from 2011 to 2020 were analyzed. The entropy method was used to calculate those indices. The coupling coordination degrees were calculated to analyze the development of the three subsystems. The results showed that the ecological, economic and social subsystems affected each other, were highly correlated, and had a high degree of coupling. They were basically at a high-level coupling state. According to the calculations of comprehensive evaluation value, the development of the ecological subsystem declined first and then rose, while the economic and social subsystems showed a steady rising trend. Gradual improvement of the ecological subsystem was closely related to the implementation of national park policy. The coordination degrees of the three subsystems have been improved steadily, and experienced four stages, including the verge of maladjustment and decline, primary coordinated development, intermediate coordinated development, and good coordinated development. Therefore, the national park plays an important role in protecting the local ecological environment and promoting economic and social development.

Progress and perspectives in the research of wetland ecosystem services.

XIAO Tao, SHI Qiang-sheng, WEN Yi, SONG Sheng-bang, WANG Zhi-qiang, ZENG Ming

2022, 41(6):  1205-1212.  doi:10.13292/j.1000-4890.202205.013

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Wetland is a type of ecosystem located in the transitional zone between land and water body. Based on its unique ecosystem structure, process and function, wetland provides various services to human society, which are of great significance for maintaining regional and national ecological security and sustainable development. Based on the basic concepts and implications of wetland and its ecosystem services, we discussed the main contents of current wetland ecosystem service researches from the following aspects: (1) the evaluation of service value; (2) trade offs and synergies among services; (3) biodiversity and wetland ecosystem services; (4) impacts of climate change; (5) impacts of land use change. Future works should strengthen the monitoring scope and intensity of basic parameters of wetland ecosystem services and the research of the relationship between ecosystem services and human well-being, and focus on wetland ecosystem disservices and ecosystem services of small wetlands.

Research progress in the regulation of genes involved in alleviating plant aluminum toxicity.

YANG Hui-qin, HE Si, ZHANG Jin-biao

2022, 41(6):  1213-1220.  doi:10.13292/j.1000-4890.202206.001

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Aluminum is one of the most important factors that lead to soil acidification and inhibition of plant growth. It has negative effects with different magnitudes on plant growth, physiological and biochemical process, as well as processes at cell level and gene level. How to improve the aluminum tolerance of plants and alleviate the toxicity to plants has been a concern for many years. Here, we gave a review on the research progress of gene regulation related to alleviating aluminum toxicity in plants from the aspects of organic acids, active oxygen metabolism, plant hormones, and mineral nutrients. It is well known that organic acids play an important role in mitigating aluminum toxicity in plants. This is the most important progress in this field, which were mainly introduced in this review. We suggested that more attention should be paid to the research of organic acids in alleviating aluminum toxicity, and that the research on genes, transcription factors and their mechanisms closely related to alleviating aluminum toxicity in trees should be strengthened.

Research progress on strategies of seed defense from predators.

CHEN Ying-zhuo, HUANG Zhi-huan

2022, 41(6):  1221-1230.  doi:10.13292/j.1000-4890.202206.007

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Seed is the main reproductive form of seed plants. The appearance of seeds enables plants to have high tolerance to various environments during the seedling stage. Furthermore, seeds can be easily spread in various forms, which is one of the important factors accounting for the dominance of seed plants in nature. Most seeds contain essential nutrients for the next generation, making them a good food source consumed by seed predators. In this review, we classified seed defense strategies into three main types including direct, indirect, and space-time defense, and other complex forms. Some hot questions in the research area of adaptive strategies of seed defense are briefly mentioned. We propose that future studies of the evolution and maintenance of seed defense strategies would provide a more general understanding of seed defense in diverse plant species.

The second-order forward selection sampling optimization method for monitoring soil quality of urban green space: A case study of Shanghai City.

ZHANG Wei-wei, HAN Ji-gang, QIU Yue, ZUO Shu-di, Abiot MOLLA, REN Yin

2022, 41(6):  1231-1239.  doi:10.13292/j.1000-4890.202206.019

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In the processes of designing urban green land soil monitoring system, there is a technical problem with respect to optimize the existing monitoring sites through an easy to operate, low-cost and representative optimization method which considers multiple soil quality indices. Aiming at the optimization of soil quality monitoring of urban green space in Shanghai, we proposed a technical framework for the optimization of the secondorder forward sampling. The Sandwich spatial sampling model and Kriging interpolation method were used to evaluate the accuracy of existing point positions. Spatial simulated annealing was used to add extra points on the existing sampling system, considering the spatial characteristics of spatial autocorrelation and heterogeneity of various soil indicators. Then, the final scheme was used to test whether the optimal design number could meet the minimum number requirement of the stratified sampling method. The results showed that the sampling variance of the existing monitoring sites was lower than 10% of the mean values of nutrients and heavy metals concentrations in Shanghai green space soils. However, the representativeness of certain elements in Pudong, Jing’an, Hongkou and Xuhui Districts needed to be improved. The mean Kriging variance could be reduced by 64.5% by adding 350 monitoring sites. This multiobjective optimization method balances the equity between the accuracy and the cost, and helps city managers to build a reasonable monitoring program for urban green space.

Landscape connectivity evaluation and temporal-spatial characteristics of Guiyang City from 2008 to 2017 based on MSPA and MCR models.

LI Yi-xin, LI Jing, CHEN Hui, WANG Zhi-jie

2022, 41(6):  1240-1248.  doi:10.13292/j.1000-4890.202206.020

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Due to the coupling interaction of rapid urbanization and ecological civilization construction, the ecology and environment of karst cities are becoming more and more fragile and vulnerable, with consequences on ecological security and landscape sustainability. Taking Guiyang, a typical city with karst landscape in Guizhou Province, as an example, we applied Morphological Spatial Pattern Analysis (MSPA) method to identify ecological sources, used the minimum cumulative resistance model to evaluate the landscape connectivity of Guiyang in 2008, 2013, and 2017, and analyzed the temporalspatial change features of landscape connectivity. The results showed that from 2008 to 2017, the landscape types of Guiyang were characterized by enhancement of area of forests, construction lands and unused lands, but reduction in the area of cultivated lands. Within the study period, the core area of Guiyang landscape pattern continued to increase, the landscape connectivity increased slightly, the isolated island area increased significantly, and the degree of landscape fragmentation was serious. The overall connectivity of Guiyang landscape was good, with more than 74% of the study area being middle or high connectivity. Within the 10 years from 2008 to 2017, the level of landscape connectivity in Guiyang showed a trend of weakening first and then strengthening in the central city, and gradually strengthening in the surrounding area. The length and the number of landscape ecological corridors in Guiyang first decreased but then increased. Our results can provide reference to further optimizing the spatial pattern of karst mountain cities and constructing ecological security network.