Table of Content

10 March 2005, Volume 24 Issue 03

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Function of Ficus in tropical rainforest ecosystem in Xishuangbanna

WEI Zuodong, YANG Darong, PENG Yanqiong, XU Lei

2005, (3):  233-237. 

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Figs are one of the key species in the tropical rainforest of Xishuangbanna.Through offering habitats and foods to all kinds of animals,plants and microorganisms,they help to maintain the biodiversity in the tropical rainforest ecosystem.Some species of figs are stangler plants which play important roles in the succession and renovation of forests.Some of the species are pioneers which can accelerate the progress of vegetation restoration.The protection of Ficus species in the rainforest of Xishuangbanna is a critical step in maintaining the structure and function of the rainforest ecosystem.However,the overexploitation has made the tropical rainforest fragmented and resulted in significant decrease in fig population sizes and the quantity variation in species and populations of fig wasps and frugivores which feed on figs.Only the colony of Ficus was conserved,which is one of the important measures,could the whole ecosystem of the tropical rainforest be rehabilitated.

Biomass of tropical secondary Mallotus paniculatus forest in Xishuangbanna

FENG Zhili, ZHENG Zheng, TANG Jianwei, SONG Qishi, ZHANG Jianhou

2005, (3):  238-242. 

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Employing standard tree regression analysis (for trees) and harvest method,the biomass of tropical secondary forest dominated byMallotus paniculatus in Xishuangbanna was studied. Total biomass of a 10-year-old community was 57.819 t穐m^-2,with the biomass of tree,shrub,inter-layer and herb layers 51.019 t穐m^-2 (88.24% of community biomass),5.644 t穐 m^-2 (9.76%),1.013 t穐m^-2 (1.75%) and 0.143 t穐m^-2 (0 25%),respectively. From the 5-year-old to 10-year-old plant community,biomass of tree,shrub and inter-layer layers increased by 105.04%,122.73% and 93.32%,respectively,while that of the herb layer decreased by 83.53%. The biomass was mainly concentrated in a few dominant species in the tree layer. Biomass of Mallotus paniculatus,Litsea sp. and Ficus sp. reached 26.170 t穐m^-2,accounting for 51.29% of tree layer biomass. The smaller DBH classes mainly contributed to the biomass of tree layer,and organs in the tree layer ranked in order of stem>branch>root>leaf.

Ecophysiological characteristics of three native species used in two forest reconstructing models

CAI Xi'an, PENG Shaolin, ZHAO Ping, LIU Hui, RAO Xinquan

2005, (3):  243-250. 

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It is of importance to utilize native species to reconstruct forest.Three native species of Acronychia pedunculata,Castanopsis hystrix and Michelia macclurei were respectively planted in man-made gaps and under Acacia mangium forest which was cut evenly at fifty percent.Their physiological characteristics such as chlorophyll content,net photosynthetic rate (Pn),transpiration rate (Tr),stamatal conductance (Gs),and water use efficiency (WUE) were measured.The results showed that there were higher photosynthetically active radiation (PAR) and relative humidity (RH) of air,and lower air temperature (T air) in gaps than under forest canopy layer.The leaves of 3 tree species in gaps were smaller and thicker,and the dry mass per unit area and chlorophyll content of leaves were much higher in gaps than under the canopy layer.In winter,the daily changes of Pn of A.pedunculata and C.hystrix showed single-peaked curve model in gaps and under canopy layer,while that of M.macclurei showed bimodal curve model in gaps and single-peaked curve model under canopy layer.The daily changes of Tr in leaves of the 3 species all showed single-peaked curve.Similar tendency in daily Gs of the 3 species in gaps and under canopy layer was shown,which was similar to the daily tendency of PAR and reverse to the RH.The WUE of A.pedunculata and C.hystrix were higher in gaps than those under canopy layer,while that of M.macclurei was reverse with no significant difference.In summer,all the 3 species had similar changes in Pn to that of the winter.The Tr of C.hystrix and A.pedunculata were higher in gaps than under canopy layer,while that of M.macclurei under canopy layer was higher than that in gaps.The tendency of Gs of the 3 species in summer was also similar to that of PAR,and reverse to that of RH.The WUE of A.pedunculata and M.macclurei were higher in gaps than under canopy layer,while that of C.hystrix were reverse.The WUE of M.macclurei was the highest among the 3 species in winter or summer,and that of the 3 species were all higher in winter than in summer.It could be concluded that A.pedunculata and C.hystrix grew better under the canopy layer and M.macclurei grew better in gaps.

Effects of covering with outer shading screens during hot-dry season in tea plantation

XIAO Runlin, WANG Jiurong, TANG Yu, LIU Yongsheng, PENG Wanxia, SONG Tongqing

2005, (3):  251-255. 

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Effects of outer shading screens on tea ecology and physiology in red soil hilly region were studied.The results showed that when the tea plantation was covered with outer shading screens during the hot-dry season,the temperatures of atmosphere,tea crown,tea leaf surface,soil surface and soil at every observational time were lower apparently than those of tea plantation without screens.The soil water content,atmosphere humidity and leaf water content in tea plantation with screens were much higher; and the contents of chlorophyll,caffeine and amino acids increased significantly while the polyphenol content decreased by 11.6%.After 27～29 days of continuous hot-dry weather,the transpiration rate,stomatal conductance and net photosynthetic rate of tea with screens were obviously higher than those of tea plantation without screens.

Effects of soil moisture on growth characteristics of Leymus chinensis seedlings under different temperature conditions

XU Zhenzhu, ZHOU Guangsheng

2005, (3):  256-260. 

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The experiment was conducted to stimulate the responses of growth characteristics of L.chinensis seedlings to 5 soil moisture and 5 temperature levels in the control growth chambers.The responses of biomass to soil moisture were altered with different temperatures.The curve equations of response of plant biomass to soil moisture were cubic or quadratic at 20～26 ℃,but were exponential at 29～32 ℃.Light and moderate soil droughts slightly promoted the growth at lower or moderate temperatures,while light and moderate drought significantly limited its growth at higher temperatures,indicating the higher sensitivity of Leymus chinensis seedling to soil water stress at higher temperature.Under moderate temperature (26 ℃) condition,there was a linear relationship between the contribution or ratio of root and shoot,and soil moisture.It was suggested that elevated temperature may strengthen the effects of soil drought on the seedling growth,resulting in a decline of adaptability to soil drought for L.chinensis.

Succession and its mechanism of cotton pests in Xinjiang

LI Jinbu, LÜ Zhaozhi, WANG Dengyuan, TIAN Changyan

2005, (3):  261-264. 

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The succession and its mechanism of cotton pests in Xinjiang were summarized in this paper.From 1950s to 1960s,the main pests were yellow cutworm (Agrotis segetum),tarnished plant bug (Lygus pratensis),tobacco thrips (Thrips tabaci),and aphid (Aphis medicaginis);while from 1970s to 1980s,the main pests were cotton bollworm (Heliothis armigera),tobacco thrips (Thrips tabaci),aphid (Acyrthosiphom gossypii),and two-spotted spider mite (Tetranychus urticae);and from 1990s,the main pests were cotton bollworm (Heliothis armigera),cotton aphid (Aphis gossypii),and two-spotted spider mite (Tetranychus urticae).The main reason for this succession might be the changes in crops distribution,cultivation type,planting method,management technique and over-use of chemical pesticides and fertilizers.

Physiological and ecological responses of maize seedlings to cadmium stress

LIU Jianxin

2005, (3):  265-268. 

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Maize seeds were soaked in solution with different concentration of cadmium (Cd²) and cultured routinely in doors.Germination of seeds and physiological and ecological responses of seedlings were studied.The results showed that Cd² could affect germination of seeds and growth of maize seedling.Maize seed germination rate was inhibited when the concentration of Cd²was higher than 50 mg稬^-1.With Cd² concentration increase,main root length and lateral root number were decreased.Cd²could promote seedling height,dry matter weight of root and shoot when its concentration was lower than 5 mg稬^-1.However,when the concentration was higher than 5 mg稬^-1,inhibition effects could be observed,with the root activity and the content of chlorophyll reduced and malondialdehyde (MDA) content increased in root.Cd also affects the absorption of other mineral elements.For example,it could promote the absorption of Ca,Mg,Fe and Cu in root and shoot,and inhibit the absorption of K and Zn.

Effects of fairy ring growth of Armillaria luteo-virens on soil fertility and plant community

WANG Qilan, JIANG Wenbo, CHEN Bo

2005, (3):  269-272. 

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The differences of plant diversity,community composition,number of different taxonomic groups of microorganism,and water content on and outside the fairy rings of Armillaria luteo-virens were investigated in Ebao village,Qilian county,Qinghai Province,from July,1997 to August,1998.The results showed that the vegetation community on fairy ring was composed differently from that outside of it,but both of them had the same dominant species.The species number and total plant cover on fairy ring were obviously higher than that outside the ring.In surface soil layer,the water content,available P and N content on fairy ring were significantly higher than that outside the ring,while there were no obvious difference in changeable Ca² and Mg² ,organic matter content and pH.Their trend was similar in deep soil layer except for water content.The number of bacteria,actinomyces,fungi and cellulose decomposer on fairy ring was obviously higher than those outside of it in surface soil layer,respectively,while there was no significant difference between them in deep soil layer.

Topsoil microbial carbon and nitrogen and enzyme activity of different city zones in Nanjing,China

WANG Huanhua, LI Lianqing, PAN Genxing, WU Xinmin

2005, (3):  273-277. 

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Much attention has been paid to the pollution of urban soils and its impact on environmental quality and social development.But little has been known about its microbial habitat.In this paper,the Nanjing city was divided into six zones as smelter industry,inner commercial,inner residence,newly developed,urban green area and preserved scenic zones.The microbial biomass C and N,urease activity and catalase activity in these six zones were analyzed and the influencing factors on their distribution and variation were discussed.High contents of microbial biomass C (C_mic) and N (N_mic) was found in the green area and preserved scenic zones,while low contents in the newly developed and the inner commercial zones.Principal component analysis showed that urease activity,C_mic and catalase activity were the main parameters contributing dominantly to the principle factors.Compared with the results of agricultural soils reported elsewhere,the urban soils of Nanjing city had wide variation both in the ratio of C/N and in C_mic/C_org.All these results supported that the urban environment was largely disturbed by anthropogenic stress and the microbial community was greatly modified.

Dynamic characteristics of soil collembolans in the birch forest of Xiao xinganling

DONG Weihua, YIN Xiuqin

2005, (3):  278-282. 

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Dynamic characteristics of soil collembolans in the birch forest of Xiao Xing’anling were studied from 1995 to 1997.Totally 3631 soil collembolans belonging to 10 families were obtained,among which,Isotomidae,Onychiuridae and Hypogastruridae were dominant and their amount reached 90.22% of the total.The individual numbers and the family numbers of soil collembolans in 1997 were the highest.The monthly dynamics of individual numbers of soil collembolans was June<August<October,while the family number of August was the highest.The vertical distribution of soil collembolans tended to decrease with the increaseing depth.In each soil layer,the percentage of individual number increased with time.Isotomidae,which has the most individual number accorded with the law of vertical distribution and temporal dynamic especially.The changes of Shannon-Weiner diversity index,Margalef richness index and Pielou evenness index were similar,contrary to that of Simpson dominance index.The monthly dynamics of diversity was August>June>October.The values of richness and diversity index in 1997 were higher than those in 1996,and the values of the richness,diversity and evenness of August in 1997 was the highest.

Influential factors on the scatter hoarding of rodents

LU Jiqi, ZHANG Zhibin

2005, (3):  283-286. 

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Scatter hoarding,employed by a variety of rodents,can play a positive role in seedling recruitment,plant regeneration,succession of communities and the maintenance of ecosystem.In order to maximize the benefit from food-hoarding,rodents will manage their caches through various ways,e.g.,optimal transporting distances,distributing their caches in wide space in an optimal density,and minimizing the loss of hoarded food.Many factors potentially influence the management of scatter-hoarded food of rodents,which can be classified into internal and external factors.The internal factors refer to sex,age and social relationship,while the external factors may include food characteristics,competition and pilferage,environmental conditions,and so on.These factors are correlated functionally rather than independently.Protocols of experiments within enclosures or arena can affect not only the food-hoarding and management of rodents but also the results of studies.Some important factors,such as predation risk,age and sex of animal,should be considered in the future studies.The more we learn about the management of scatter hoarding,the better understanding we will have on the interaction between rodents and various plants.

Environmental problems and ecological countermeasures of coal-mining areas in the old industrial base,Northeastern China

ZHOU Qixing, ZHANG Qianru

2005, (3):  287-290. 

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On the basis of analyzing main environmental problems in coal-mining areas of the old industrial base,Northeastern China,some ecological solutions were tentatively suggested.These ecological countermeasures included an emphasis on ecological sustainability in coal-mining areas,a valuable reference using the experience of best practices from Australia,and pushing ecological multi-purpose mode of land restoration and remediation integration as an important direction of environmental protection in the area.

Spatial-temporal changes and optimal regulation of cultivated land in wetland nature reserves—A case study in Tongjiang City of Sanjiang Plain.

HOU Wei, ZHANG Shuwen, KUANG Wenhui

2005, (3):  291-295. 

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Taking Tongjiang City of Sanjiang Plain as an example,spatial and temporal changes of cultivated land in typical wetland natural reserves were studied quantitatively,with driving forces analyzed and optimal regulation measures were put forward.The results indicated that the area of cultivated land has increased by 299,2258 hm² from 1954 to 2000,and the proportion increased from 1.37% to 49.58%.Landscape diversity increased from 0.4723 to 0.7436.Cultivated land has become the main land use type in this region.The decrease of wetland area led to the declination of ecological function,which has become the most important factor threatening the grain safety.Cultivated lands should be protected and optimally regulated.

Advances in terrestrial net primary productivity (NPP) estimation models

ZHU Wenquan, CHEN Yunhao, XU Dan, LI Jing

2005, (3):  296-300. 

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Net primary productivity (NPP) estimation is an important study field of global change and terrestrial ecosystems (GCTE).Climate-productivity relationship models,eco-physiological processing models and light utilization efficiency models are the three main kinds of models for terrestrial NPP estimation.The achievements and problems of these models were reviewed comprehensively and systematically,and a strong development trend of NPP estimation was presented in this paper.Present research on the terrestrial NPP estimation mainly focus on the eco-physiological process models,and the regional scaling is the key problem of their application.Light utilization efficiency models based on remote sensing are an absolutely new method for NPP estimation in recent years.Remote sensing information can be used in a relatively simple modeling framework to estimate global NPP of terrestrial vegetation from direct satellite observations.However,their fundamental understanding of ecological process is not clear.Substantial studies showed that remote sensing applications,coupled with the eco-physiological process models,would be a major developing field in the estimation of terrestrial NPP.It can enhance our ability to model the spatial pattern and dynamics of NPP at both regional and global scales.

Research advances in the relationship between alpine timberline and climate change

WANG Xiaochun, ZHOU Xiaofeng, SUN Zhihu

2005, (3):  301-305. 

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There is little doubt that the global climate is experiencing exceptional changes.The rate of warming during the 20 th century was the greatest in the last 1000 years,with the 1990s being the warmest decade.As the boundary zones between major ecosystems,ecotones are important sites for monitoring the effects of global change.The forest-tundra ecotone,formed by alpine timberline,may be especially sensitive to climate change.Research advances in the relationship between alpine timberline and climate change were briefly summarized from the relationship between single tree and weather conditions,the regeneration of trees under climate change,the pattern of alpine timberline,and the methods adopted in the research on the relationship between alpine timberline and climate change.At last,the problem in the research on alpine timberline was listed,and the research trends in the future were also prospected.

Application of stable isotopic approach in ecology: A review

YI Xianfeng, ZHANG Xiaoai

2005, (3):  306-314. 

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Great progress has been made in stable isotope approach to diet composition,migration and trophic position relationships as well as food webs in ecosystems in the last century.However,fewer domestic reports touched on this subject.It is necessary to mention isotopic effect and measurement of isotopes and to explain how to apply this technique to diet information,migration and trophic position relationships and food web analyses of ecosystems.

Research advances in response of seed plants to enhanced ultraviolet-B radiation

REN Jian, LI Chunyang

2005, (3):  315-320. 

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Depletion of ozone leads to the increase of Ultraviolet-B radiation on the surface of the Earth.Enhanced UV-B would affect the growth of plants at different extent.This review summarized the research advances in response of seed plants to enhanced Ultraviolet-B radiation in recent years.According to previous studies,higher plants sensitive to UV-B decreased in plant height,leaf area and stem length,with the integrity of chloroplast structure damaged.Photosynthetic organs,genetic material,and proteins etc.are the main targets of UV-B.In order to alleviate the harmful effects of UV-B,plants developed a range of protective mechanisms,including the dispersion and reflectance of UV-B by epicuticular structure and leaf thickening,accumulation of UV-absorbing compounds,reparation of DNA damage and elimination of active radicals.In addition,UV-B significantly interacted with drought and elevated CO₂.Research on response of woody plant and ecosystem to enhanced UV-B radiation should be emphasized in the future.

Secondary metabolites of Phaeocystis:A review

PENG Xichun, YANG Weidong, LIU Jiesheng, PENG Zhiying

2005, (3):  321-326. 

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Phaeocystis,belonging to the marine microalga genus (Prymnesiophyceae),is a eurythermy and euryhalinity species which has a worldwide distribution.As one of the primary producers of marine environment, Phaeocystis produces alarge amount of organic secondary metabolites such as carbohydrates,dimethylsulphoniopropionate (DMSP)/dimethylsuphoni-opropionate (DMS),carbon disulphide and toxins that have significant effects on the marine and air environment.The complicated factors and mechanism of the synthesis of these productions are still being argued.This paper summarized the advances of relative studies.

Analysis of Boron background concentration and pollution status of water in Kuandian County

WEI Chun, XING Xiaoru, ZHANG Haibo, WU Guoping, WEI Fusheng

2005, (3):  327-329. 

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water samples of Kuandian County, Liaoning Province, were collected and B concentrations in these samples were analyzed with ICP-MS. The results showed that the background B concentration of water in Kuandian County was equivalent to the level of the world, but the B concentrations of surface water and underground water in polluted areas were 23.1 and 495.6 times of that in background areas, respectively. Mining and processing B had resulted in serious B pollution to surface and underground water.

Analysis methods of phytochelatins

ZHAO Di, XIA Lijiang, ZHU Yongguan

2005, (3):  330-334. 

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Phytochelatins is a kind of peptides rich in cysteine,which can bind the ion of heavy metals.Phytochelatins has a common structure: [γ-Glu-Cys ]_nGly (n=2～11),and it is one of the key factors of plant heavy metal tolerance mechanism.Its analysis methods can be applied to study plant heavy metal tolerance mechanism.The article introduced the basic theory of phytochelatins analysis,and analysis methods including Spectrophotometer,HPLC and CE,among which the HPLC was presented in detail.

Dynamic simulation of phosphorus nutrient in crop-soil system

ZHUANG Hengyang, CAO Weixing, LIU Chuansong

2005, (3):  335-338. 

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The dynamic simulation models of phosphorus nutrient in crop-soil system were developed in this paper.In the models of phosphorus dynamics,maximum phosphorus absorption capacities were estimated with the concentrations of metal oxides in acid soils and with the clay percentages in other types of soils.The relationship between total available phosphorus and the equilibrium solution phosphorus concentrations in soil was described with the Langmuir function.The functional relations of above-ground critical phosphorus concentrations to PDT were established.The models were tested by phosphorus concentrations in wheat plants,indicating satisfactory agreements to the experimental data.

Climatic diagnosis of brown planthopper occurrence degree in single late rice

LI Jun, JIANG Yaopei, YANG Qiuzhen, WANG Zhixiong

2005, (3):  339-342. 

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By mathematic statistics,the paper analyzed the relations between the occurrence degree,early dates of brown planthopper and climatic-biological factors in single late rice in Shanghai.The results showed that the occurrence of early dates significantly correlated with rainfall days from April 16 to 30 and average ridge position of sub-tropical high-pressure on 500 hPa layer from 110? to 150癊 of the last October,and their coefficients were -0 6307 and 0.4781,respectively.The occurrence degree related to mean minimum temperature from January 1 to February 10 and rainfall amount in July,and their coefficients were -0.5218 and 0.5203,respectively; while the coefficient for average ridge position of sub-tropical high-pressure on 500 hPa layer from 110? to 150癊 of last December was -0.5374.When El Nino appears strong in spring,brown planthopper occurrence in Shanghai single late rice will be serious during that exact year.When El Nino appears medium or plus in autumn,the occurrence situation will be serious during the following year.The analysis also showed that La Nina had no obvious relations with the occurrence degree.

Synthetic assessment on pollution level and potential ecological risk of heavy metals in Kaozhou Bay.

CAI Wengui, LIN Qin, JAI Xiaoping, WANG Zenghuan, LI Chunhou, YANG Meilan

2005, (3):  343-347. 

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Based on integrative model and supported by Geographic Information System (GIS),the pollution level and potential ecological risk of heavy metals in surface water and surface sediment in Kaozhou Bay were assessed synthetically with chemical and ecological methods,and the results of different methods were compared.The pollution indexes of heavy metals in the water of the whole bay were lower than 0.5 in dry season and even lower than 0.2 in flooding season,which indicated that the contents of heavy metals were low and insufficient to affect the ecological system in the bay.In dry season,the potential ecological risk indexes of heavy metals in the surface sediment of most part of the bay varied from 20 to 70 with the dense area occurring in the west and northwestern part,with sediments slightly affected by heavy metals.While in flooding season,the risk indexes in the whole bay were lower than 20 and would not affect the ecological system.As for ecological assessment,food organism level in dry season in most part of the bay ranged from grade 2 to grade 3 with the dense area occurring in the northwestern part,the mouth of the bay and the estuary of Jilong River,whose levels reaching grade 4,indicating rich food organisms in these parts.In flooding season,the dense area was distributed in the middle part of the bay and the coastal area along Wangjingzhou with the level of grade 4～5,and followed by the mouth of the bay with the level of grade 4,while in the west and northwest of the bay the levels were the lowest with grade 1～2.Because of the low level of heavy metal pollution,the environmental factors,such as water temperature,salinity and nutrients,had turned into the major factors which affected the ecological system in the bay.Comparing for the various assessment methods,synthetic assessment was an effective approach to describe the pollution of heavy metals and forecast the impact on the ecological system.

Analysis on unqualified ecotourism practice: From the point of view of stakeholders

LIU Xuemei, BAO Jigang

2005, (3):  348-353. 

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Despite the considerable literature defining what ecotourism is or should be,`Ecotourism' is experiencing various practices with different features.Now the term `Ecotourism’ is almost applied to all tourism activities that are based on nature.Faced to the flooding of those unqualified ecotourism,it is of great necessity to put forward professional claim.The writer holds that the key to the realization of rigorous ecotourism chiefly lies in the relationships among the different interest groups involved.So the focus of this paper is to give a special analysis to the interest relations among those stakeholders,which include local government,tour operators,local residents and ecotourists,and thus help to find out what’s wrong with those unqualified ecotourism and the roots of those problems.