Table of Content

25 September 1999, Volume 10 Issue 5

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Articles

Storage dynamics of fallen trees in Korean pine broad-leaved forest

Dai Limin, Xu Zhenbang, Yang Liyun, Cao Yuming

1999, 10(5):  513-517. 

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Based on the previous researches on fallen trees in forest, the storage dynamics of fallen trees in Korean pine broad-leaved forest in Changbai Mountain and its relation to the dynamic patterns of their decomposition were studied. The study revealed that the decomposition of the fallen trees was from the surface to the inside, except the heart-rot woods. Under the same ecological conditions, the decomposition rate was decided by their species, diameter and position. The storage dynamics of fallen trees in Korean pine broad-leaved forest included two aspects, i.e., the storage now available and the annual input of fallen trees. The dry existing fallen trees reduced rapidly during the first 100 years storage, and the decomposition of the basswood was faster than that of the Korean pine, the former being decomposed 91% and the latter being72%. The storage dynamics of the fallen trees was similar with their annual input decomposition, but the former increased considerably greater, because some fallen trees were not decomposed completely. After 100 years, the existing storage and decomposition tended to stabilized at 16～17 t·hm^-2 until the climax community ended.

Fractal characteristics of distribution pattern of plant species in secondary Cupressus funebris forest in the Three Gorges region

Deng Hongbing, Zhou Yongbin, Wang Qingli, Pan Wenbin

1999, 10(5):  518-520. 

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Based on the fractal geometrical theories in nonlinear science, the fractal characteristics of distribution patterns of some major plant species in the secondary Cupressus funebris forest in the Three Gorges region were studied at middle and small scales. The box dimensions of distribution patterns of some important species were calculated. For example, the dimensions of Cupressus funebris, Ficus tikoua, and Cyperus spp. were 1.588, 1.617 and 1.627, respectively. The results tallied with those coming from classic analysis, which showed that fractal dimension is a valuable measure in this research. Further analysis of the dimensions could also illustrate the influence of human activities on species distribution patterns.

Dynamics of species diversity in secondary succession series of forest communities in Jinyun Mt

Guo Quanbang, Liu Yucheng and Li Xuguang

1999, 10(5):  521-524. 

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Based on the investigations on the secondary succession series of forest communities in Jinyun Mt. in1986 and 1996, the composition index (CI) was used to process the ordination of community succession, and to study the dynamics of species diversity. The result shows that CIwould solve the problem resulted from the substitution of time with space. In the course of forest secondary succession, the species richness tended to increase at the early stage, and then to reduce; while the species evenness did not show any obvious dynamics, which was related to the intraspecific and interspecific relations. Therefore, moderate disturbance could increase species diversity in communities.

Morphological plasticity of shade tolerance of three conifers in Changbai Mountain and regulation of hormone

Zhou Yongbin, Jiang Ping, Wang Qingli

1999, 10(5):  525-528. 

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The morphological plasticity of Pinus koraiensis, Picea koraiensis and Larix olgensis to shade tolerance, and the level and distribution of their endogenetic hormones were studied in forests with different canopy density. The morphological plasticity of Pinus koraiensis to shade-tolerance promoted the growth of apical branches and increased the specific leaf area (SLA); while that of Picea koraiensis benefited the number of lateral branches and SLA. Under low light intensity, the increasing growth of apical branches and the increasing SLA of Pinus korainensis were positively correlated to the content of endogenetic hormone Zin corresponding positions. The content of endogenetic hormone Z Rin top leaves of Picea koraiensis was positively correlated with the SLA, and the number of lateral branches was negatively correlated with the content of ABAin bifurcated positions. Among the three conifers, Pinus korainensis was the most suitable to low light intensity.

Multivariate and SDA analyses of Gordonia acuminata climatic ecotype

Ke Wenshan, Zhong Zhangcheng

1999, 10(5):  529-533. 

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Quantitative classification (CA) and ordination (PCA,COA) methods were used to analyze 23 traits of seven Gordonia acuminata geographic populations, and discriminate function analysis (SDA) was used to test the results of classification and ordination. Seven geographic populations were classified into three climatic ecological types: type Ⅰ Yunnan Wenshan, typeⅡ Guangxi, and type Ⅲ Shichuan. According to the discriminate axis figures of SDA, no position points were incorrectly classified. Through comparing the contribution rate of the geo climatic factors to each ecological type, sunlight had the principal effect on the formation and differentiation of the three climatic ecotypes.

Fluxes between agroforest ecosystem and low level atmosphere

Wang Hanjie

1999, 10(5):  534-538. 

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Based on the radiosonde data in the agroforest area in Huang Huai Hai plain, a simplified one dimensional model was established to study the momentum, heat and water vapor fluxes above the agroforest ecosystems with three different structures. It was found that because of the frictional effect, the wind velocity above the vegetation canopy increased with height rapidly, which caused an insistent downward momentum flux above the canopy. During the stable clear night, the momentum flux was significant because of the strong wind shear. It becames weak around noon,as the strong turbulence made the vertical wind shear smaller. Both heat and water vapor flux went downward in the night, which caused respectively by the radiation cooling of the vegetation canopy and by the water vapor condensation in the very low level. The heat flux turned upward after sunrise because of the surface heating, which reached to the maximum at noon when the surface super adiabat formed. The water vapor flux turned upward as well, due to the high vapor content in the lowest level caused by the evaportranspiration of the vegetation canopy at day. The author also discussed the flaw of one dimensional model and revealed some important aspects of atmosphere biosphere interaction.

Analysis on phytogeographical elements of Quercus mongolica community in northeast China

Yu Shunli, Ma Keping, Chen Lingzhi

1999, 10(5):  539-541. 

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The distribution types of 192 genera of Quercus mongolica community in10 sites of northeast China and one site of Hebei Province were analyzed, and the proportion of each type to the total as well as the ratio of temperate genera to tropical genera (T/Rratio) in each site were calculated. Among the distribution types in northeast China, those of the temperate and tropical genera accounted for 72.0% and 9.7%, respectively. The latitude and altitude could affect the genera distributed in temperate zone and their T/Rratio. The T/Rratio increased with increasing latitude, while the number of tropical genera decreased if the altitudes were the same or similar. Altitude could affect T/Rratio more obviously, causing its fluctuation with latitude. The regression equation of T/Rratio with latitude and altitude was given, and the reasons producing this distribution pattern were also explained.

Environment control techniques for vegetation restoration in dry valley of upper reaches of Minjiang River

Bao Weikai, Chen Qingheng, Chen Keming

1999, 10(5):  542-544. 

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Aimed at the principal limiting factors of vegetation restoration in dry valley of upper reaches of Minjiang River, field experiments and plot fixed observations had been conducted for three years. The optimal soil environment control techniques for vegetation restoration in large area were as follows. Before rain season in first year, site preparation along horizontal trench, digging moderate holes, and then, cultivating Astragalus hungheensis were carried out. When rain season in second year coming, Pfertilizer was applied in holes, and tree seedlings were planted. Alternatively, before rain season in first year, site preparation along horizontal trench and digging moderate holes were carried out. When rain season in second year coming, Pfertilizer was applied in holes, tree seedlings were planted, and all holes were covered by stones. These techniques were easily practicable, and expended in the region.

Dynamics of population and biomass at early natural recovery stage of vegetation on abandoned quarry of Tiantong National Forest Park

Wang Xihua, Song Yongchang

1999, 10(5):  545-548. 

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The study shows that the species composition of the community on the abandoned quarry was very simple,with only two species, Schima superba and Pinus massoniana. The trends of density dynamics of the two populations were up first and then down, with the highest densities at three and four years old, respectively. The aboveground growth of P.massoniana was faster than S.superba, and its total biomass was 12 times more. The proportion of biomass in leaves and roots of S.superba was higher, while in stems was lower than P.massoniana. It is suggested that by fast growing, P.massoniana was dominant in competition at early succession stage on the abandoned quarry. The characters of communities at the early succession stage were also compared between the quarry site and the clear cutting site, and the effective recovery of vegetation was discussed in this paper.

Variation of some characters of Songnen grassland after firing in different seasons

Zhou Daowei, Zhang Baotian, Guo Ping, Yue Xiuquan, Tian Hongyan

1999, 10(5):  549-552. 

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After firing in different season, some characters of Songnen grassland varied obviously. As compared with unfired or fired in Spring, the soil water content was lowered after fired in Autumn, but little difference was found after fired at different periods of Spring. The grass yield, population composition and species diversity after fired in Autumn were significantly lower than those after unfired or fired in Spring, but the species of annual plant increased. No significance difference was found in grass yield after fired at different periods of Spring, but top bud species decreased after fired in late Spring. Different life form species had different response on the same firing, not only in their individual growth, but also in their yields.

Preliminary studty on biomass reproductive allocation in Leymus chinensis population

Wang Renzhong, Zu Yuangang, Nie Shaoquan

1999, 10(5):  553-555. 

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The study shows that the allocation rate of the biomass in Leymus chinensis for its rhizome and vegetative growth was much higher, and that for sexual growth was less than 10%. The ratio of the biomass of rhizome and vegetative shoot was as much as 20～40% of the total, while that of seed was less that 1.5%. The low investment in sexual reproduction of L.chinensis was the main reason for its low seed production.

Electron microscopic observation on electron dense structure in cytoplasm of Ammopiptanthus mongolicus

Han Shanhua, Zhang Hong, Wang Shuang

1999, 10(5):  556-558. 

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Transmission electron microscopic observations on the mesophyll cells of Ammopiptanthus mongolicus showed that in winter time, there was a kind of electron dense structure widely distributed in cytoplasm. This kind of structure mainly located around the chloroplasts which had generally been disintegrated and had many osmiophilic globuli. Some of this structure even pasted with chloroplast envelope membranes, and few existed in well developed chloroplasts and vacuoles. The structures were different in size, usually ellipsoidal shaped or semicircular shaped. The surface of the structures did not possess a layer surround membrane and vesicular shaped structures, but a few of radiate protuberances. The structures were very dark in electron dense and their staining was quite even. The formation of a great quantity of the structures may be related with increasing coldness resistance of plants.

Ecological structure and physiological characters of tea rice intercropping system

Huang Yide, Zhang Yuping, Huang Wenjiang, Cheng Xiwu

1999, 10(5):  559-562. 

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The study on the tea rice intercropping system in west Auhui mountainous region showed that the leaf area index of this system was higher than that of the single tea garden, and the spatial distribution of its upper and lower layers was more rational. At the early growing stage of rice, the ecological boundary layer was upper tea and lower rice; while at the later stage,it was upper rice and lower tea, which was beneficial to the system to fully use light, heat, water and gas resources. Compared with single tea garden, in the intercropping system in midsummer, the relative light intensity reduced by 35.7%, the temperature after the noon decreased by 0.9～1.9℃, and the relative humidity increased by 7%. All of these provided with a suitable eco environmental condition for the growth of tea trees, and increased the growing speed rate of their new shoots. The water utilization efficiency of rice in the intercropping system was higher than that in paddy field, and the edge effect was significant. The number of effective ears per unit area and the percentage of filled spikelets were increased.

Compensation effect of millet after drought

Guo Xianshi

1999, 10(5):  563-566. 

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Studies on the physiological performance, dry matter accumulation rate, water utilization efficiency and economic coefficient of millet after drought show that millet had compensation effect after drought, which was a kind of adaptive physiological phenomenon. In the treatment that millet had been drought earlier, millet showed a tendency of extra growth, and its relative daily accumulation rate of dry matter was higher than other treatments at the same water supply level. The dry matter loss could be compensated partly or even completely through extra growth. The physiological impact of earlier drought on millet had the character of continuity. After subsequent increasing water supply, the treatment that had been drought earlier showed a higher net photosynthetic rate and a higher chlorophyll content in leaf. The compensation effect of millet also showed a higher efficiency in utilizing limited water and dry matter to produce grain. In the west semiarid area of China, autumn cropos with the character of extra growth after drought adapt the distribution of natural precipitation, comparing with summer crops.

Physiological mechanism of highly efficiency use of limited water supply by winter wheat

Shangguan Zhouping

1999, 10(5):  567-569. 

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By determining the CO₂/H₂O gas exchange in winter wheat leaves during its earring to flowering stages under different water supply, this paper dealt with the relationships of water use efficiency (WUE) with photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs), intercellular CO₂ concentration(Ci) and leaf temperature(Tl). The WUE presented a quadratic relation with Pn. It increased to a certain degree with increasing Tr, and then decreased when Tr was higher than a certain value. It decreased remarkably with increasing Ci. The increase of Tl promoted the photosynthesis and transpiration, but when T1 was up to a certain degree, it showed an inhibitory effect on WUE, indicating that in a certain range, the increase of T1 is not beneficial to WUE. With the increase of Gs, WUEreached to a certain high level and then fall down.

Analysis and application of unbalanced data from crop culture experiment

Jiang Zhixun, Li Yisong, Huang Zhongqing

1999, 10(5):  570-572. 

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With mixed linear model and MINQUE(1) method, the unbalanced data from crop culture experiment were analyzed, and the effect of ecological environment and its mutual effect with treatment combination on yield and other objective traits were revealed. The long term perplexed problem in analyzing unbalanced data from crop culture experiment was solved, and a new approach for estimating the stochastic effect of ecological environment was developed.

Difference in P uptake from low grade rock phosphate by radish and wheat on acid soil

Zhao Bing, Zhang Fusuo, Mao Daru

1999, 10(5):  573-575. 

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Based on the simulating cultivation experiments with three and two seperated compartments, the uptake effect of low grade rock phosphate by radish (Raphanus sativus) and wheat (Triticum aestivum) was analyzed. The Puptake by radish was restricted by the range of its root action. Radish could efficiently utilize rock phosphate in root compartment, and its dry weight was increased by 23.3%. Whether the rock phosphate was applied in root compartment or not, radish could only slightly utilize the rock phosphate applied in outer compartment, suggesting that it was activated by the small amount of organic acids infiltrating into outer compartment. This small part of phosphate utilized by radish could not obviously increase its dry weight. Wheat could not efficiently utilize low grade rock phosphate, whether it was applied to root compartment or outer compartment.

Transformation mechanism and availability of mutrients in albic soil plant system Ⅴ Effect of organic material on phosphorus availability in soil wheat rhizosphere system

Wu Longhua, Gao Ziqin

1999, 10(5):  576-578. 

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Rhizo box experiment showed that soil available Pwas significantly increased when decayed alfalfa was added, and soil Al Pand Fe Pwere also enhanced strikingly. The effects were enlarged when time extending. Pconcentration in wheat plants was increased significantly, and clearly related to the change of soil Al Pand Fe Pin non rhizosphere.

Transformation mechanism and availability of nutrients in albic soil-plant system Ⅳ Effect of environmental factors on phosphorus availability in albic soil

Li Fayun, Gao Ziqin

1999, 10(5):  579-582. 

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Rhizospheric experiment shows that the contents of soil moisture and organic matter and soil pHare the important factors affecting phosphorus availability in albic soil. Regulating soil moisture content could increase the solubility of iron and aluminum phosphates, and accelerate the diffusion of phosphatic ions from rhizospheric to non rhizospheric soil. High content of organic matter could decrease the free energy of phosphorus adsorption by soil, inducing an increase of Olsen Pcontent. Asuitable liming application could adjust the soil pHand enhance the solubility of iron and aluminum phosphates, due to the effect of chemical solution, and improve the biological availability of soil phosphorus.

Characteristics of sulfur forms content distribution and its acidification of acid sulfate soils

Wang Jianwu, Luo Shiming

1999, 10(5):  583-588. 

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Characteristics of sulfur forms, content, distribution and its acidification of Acid Sulfate Soils (ASS) in the southern coastal regions of Taishan city, Guangdong, are studied. The results show that the sulfur content of ASSis very high, 2 to 6 times than coastal saline soil, 3 to 9 times than paddy soil. The sulfate of ASSis mainly in inorganic forms, it covers 82.3% to 90.4% of the total sulfur in the soil. Among them, pyrite is the highest form; it covers 30.3% to 46.2% of the total sulfur in the soil. The distribution of pyrite in profile is corresponding with the total sulfur. The difference of sulfur content in the profile and between the soils is significant. The sulfur is very high in the place where near the hill. This means the suitable sulfur accumulation place is near the hill. Acidity of ASS is come from pyrite oxidation. The acidification cause pHvalue drops to 5.5, even to 2.83. The potential acidity of ASS is 2 to 3 time high than the actual acidity, the potential environmental risk of ASSis great.

Effect of calcium and silicon on growth of and nutrient uptake by wheat exposed to simulated acid rain

Liang Yongchao, Shen Qirong, Zhang Aiguo, Shen Zhenguo

1999, 10(5):  589-592. 

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Pot experiments were conducted to study the effect of calcium carbonate and sodium silicate on the acidification of red soil, and on the growth of and nutrient uptake by wheat (Tritum aestivum cv. Yangmai No.5) exposed to simulated acid rain. The result indicated that the deposition of simulated pH 3.0 acid rain onto the foliage of wheat decreased soil pHto some degree, which had no inhibitory, but promotion effect on wheat growth, due to its contained N, S, and Kelements. Applying calcium carbonate and sodium silicate to the soil before exposure, inhibited soil acidification and aluminum activation. However, the application rate of carbonate should be no more than 2.0g·kg^-1, otherwise, it would considerably decrease the bio availability of soil phosphorus, and inhibited plant growth. In contrast, adding silicate significantly increased soil available phosphorus content, and enhanced the uptake of phosphorus as well as nitrogen and potassium by wheat. Additionally, the Si fed wheat plants were found to be more resistant to wheat aphid.

Accumulation,distribution and interaction of phosphorus and zinc in wheat cells

Yang Zhimin, Zheng Shaojian, Hu Aitang, Zhao Xiulan

1999, 10(5):  593-595. 

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This paper studied the accumulation,distribution and interaction of phosphorus and zinc in the asexual cells of wheat cultured in MS solution with three levels of phosphorus(0.5,1.5,3.5 mmol·L^-1) and two levels of zinc(0,60 μmol·L^-1).An application of 60μmol·L^-1 Zn and 0.5～1.5mmol·L^-1 P increased the reproduction and the dry matter yield of wheat cells,while the supply with no Zn or high P(3.5 mmol·L^-1) showed an inhibited effect.The accumulation of P and Zn in cells increased with increasing P and Zn supply. In comparison with Zn-deficiency,an application of 60μmol·L^-1 Zn reduced the P content in cells cultured for 7 days. 0.5～1.5 mmol·L^-1 P enhanced Zn accumulation in cells, but decreased it under 3.5 mmol·L^-1 P. As much as 83.9%～88.3% of the total P was associated with thecell walls, and the more the P supply,the greater the P content in them.The results also showed more than half of Zn (52.0～60.5％)in cells was examined in cell walls.In contrast to the cell walls,the contents of P and Zn in vacuoles were much lower,with 2.3～3.8% and 10.6～30% respectively.

Correlation analysis between UDS and MCN in Vicia faba treated with Cd²⁺ and Al³⁺ and UDS technique in higher plants

Chang Xuexiu, Wen Chuanhao, Wang Huanxiao

1999, 10(5):  596-598. 

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With the method of inserting3H TdRinto DNA, this paper studied the inductive effect of Cd²⁺ and Al³⁺ on unscheduled DNA synthesis (UDS) and micronucleus (MCN) in Vicia faba, the correlation between UDS and MCN, and the feasibility of using higher plant UDStest as the indicator to detect environmental mutagens. The results indicated that both Cd²⁺ and Al³⁺ could induce UDS and MCN in Vicia faba. There was a negative relationship between UDS and MCN, but it was not significant. The relationship between UDS and MCN was similar under the treatments of Cd²⁺ and Al³⁺ respectively. It was reliable using higher plant UDS test as the indicator to detect environmental mutagens within certain dosage range.

Test and improvement of model reliability for predicting insecticide residue

Wang Yujie, Zhang Dake

1999, 10(5):  599-602. 

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According to the theory of condition number of matrix, this paper provided a method for testing the reliability of predicting model,and on the basis of ridge regression theory,the method for improving unreliable predicting model was built, which was tested by predicting the residue dynamics of fenvalerate in cabbages.The results showed the precision of predicting model was increased by a big range.

Genetic diversity of chinese pig breed in different ecological environment

Chen Hongquan, Jiang Moyou

1999, 10(5):  603-605. 

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The relationships between gene frequency of the serum protein loci Tf, Am, Pa and Cp of some local pig breeds in china and ecological environment, and their variation patterns were studied by least square analysis. There were 3 alleles at Tf, Am, and Cp loci, respectively, and 2 alleles at Pa locus. The gene frequencies among6 geographical pig types and among8 ecological areas varied significantly (p<0.05), indicating that the effects of geographical type and ecological environment on the gene frequency and heterozygosity were obvious. Dongting Hong Lake area, Xianjiang River Poyang Lake area, and Taihu Lake area could be regarded as the starting point of up and downward frequency in chinese pig breeds.

Dispersal behavior of alfalfa leafcutter bees of pollination and its effect of increasing alfalfa seed production

Zhang Qingwen, Zhang Weiwei, Cai Qingnian, Chen Heming

1999, 10(5):  606-608. 

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Field investigation show that the alfalfa leafcutter bees dispersed around their beehives. The dispersal and pollination effect decreased with the distance, and differed with direction. High, middle and low effective areas were defined with seed yields of ≥50, 50～30, 30～15g·m^-2, respectively. In high and middle effective areas, the dispersal distances in northeast direction were the longest, with 50 and 60 m respectively, and next by east and north directions. In low effective area, the dispersal distances in north direction was the longest, with 100m, next by northeast, northwest, west, south, southwest and southeast directions. Based on the above results, a map with high, middle and low effective areas of alfalfa leafcutter bees pollination were drawn, from which, the ranges of these three areas could be directly seen.

Diversity of soil animals in Confucian graveyard of Qufu

Liu Hong, Yuan Xingzhong

1999, 10(5):  609-611. 

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In this paper, the soil animals in Confucian graveyard of Qufu were investigated. 5456 specimens were collected, which belonged to 5 phylums, 11 classes and 24 orders. The dominant groups were 3 sorts, and the common groups were 8 sorts, accounting for 95.12% of the total. The composition of soil animals in4 habitats was extremely similar, and most of them concentrated in the surface horizon. The diversity and evenness indexes in different habitats were in order of mixed forest> Platycladus forest> Quercus acutissima forest>grassland. In the whole Confucian graveyard, the diversity and evenness indexes of soil macro animals were greatly higher than those of mid small animals.

Influence of drug form and host state on germination and infection of Beauveria bassiana

Lin Huafeng, Li Zengzhi, Hu Cui

1999, 10(5):  612-614. 

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Under appropriate temperature condition, the infection process of Beauveria bassiana and the host death rate of host were faster in liquid treatment than in powder treatment, which was due to their different humidity. The conidia could not germinate and infect host at low atmospheric temperature (0～10℃). The development of B.bassiana in dead hosts was faster than that in living hosts. Both the hosts after low temperature treatment and the fresh hosts had the same resistance to infection. Therefore, it is unsuitable to control Dendrolimus punctatus in forests through releasing fungus in winter.

Phosphorus transfer via mycorrhizal hyphal links from red clover to rye grass

Ai Weidang, Zhang Junling, Li Long, Li Xiaolin, Feng Gu

1999, 10(5):  615-618. 

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Afive compartments system was used to examine ³²P transfer via vesicular arbuscular mycorrhizal hyphal links from red clover to rye grass. The results show that after mycorrhizal fungus were inoculated in the root compartment for donor plant, hypha out of the donor's roots penetrated the central compartment, and reached the root compartment for receiver plant and inoculated its roots. Therefore, hyphal links were formed between roots of donor red clover and receiver rye grass, and could transfer ³²P from red colver to rye grass. The amount of ³²P transfer was decreased as Psupplied to the receiver plant increased.

GIS based ecotope types and their relationship with survival of Bos gaurus readei

Zhang Hongliang, Wang Renchao, Li Zhixi

1999, 10(5):  619-622. 

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With the support of ARC/INFOand ARC/VIEW, the graphic data on the basic elements of ecotopes were overlapped and analyzed, and the ecotope patterns in Nabanhe Nature Reserve of Xishuangbanna were identified. Based on these, the relationship between the ecotope types and the habitas of Bos gaurus readei was analyzed with the applications of Bayes decision and subordination degree of fuzzy mathematics. The result shows that the probability of the suitability for Bos gaurus readei was 0.292 in the tropical seasonal rainforest habitat type, 0.600 in the subtropical monsoon evergreen broad leaved forest, and 0.108 in subtropical bryo evergreen broad leaved forest, which suggests that the damage of tropical forest had threatened the habitat of Bos gaurus readei.

Ecological stress and environmental construction in mountain resorts: A case study in Taishan Mountain resort

Cui Fengjun

1999, 10(5):  623-626. 

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By the methods and principles of tourism ecology, 8 first level and 6 second level indicators with their computing models were designed to measure the integrated ecological stress in mountain resorts. Taking Taishan Mountain resort as a case, its 13 functional zones were divided into 3 grades according to the intensity of ecological stress. Some effective ways of ecological compensation were also put forward to eliminate the ecological stress and to maintain sustainable development, which could be used to coordinate the relationship between physical environment and tourism activities in mountain resorts.

Growth and ecological conversion efficiency of black snapper and their main affecting factors

Sun Yao, Zhang Bo, Guo Xuewu, Wang Jun, Tang Qisheng

1999, 10(5):  627-629. 

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Running water simulating experiment shows that specific growth rate (SGR) of black snapper (Sabastodes fuscescens) increased deceleratedly with increasing ration, and after increasing to a peak value,the SGRor ecological conversion efficiency (Eg) gradually decreased with increasing temperature and ration.Under experimental condition,the maximal and optimal growth temperature was 16.3℃ and 15.8℃,and the maintenance and optimal ration was 0.79% and 4.10 % of black snapper's weight,respectively.Both SGRand Eg decreased with the increment of body weights.Feeding on small sized fish was beneficial to the growth of black snapper,but did not significantly affect its ecological conversion efficiency.

Biological nitrification denitrification and nitrogen loss in rice field ecosystem

Yu Shen, Li Zhengao

1999, 10(5):  630-634. 

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From the viewpoint of soil microbial physiology and biochemistry, this paper reviewed the advances on the research of biological nitrification denitrification and nitrogen loss in rice field ecosystems. The position and significance of biological nitrification denitrification in the gaseous nitrogen losses of rice field ecosystems were also discussed. In addition, the measuring methods for the biological nitrification denitrification were compared in the paper.

Ecosystem services and their economic valuation

Ouyang Zhiyun, Wang Rusong, Zhao Jingzhu

1999, 10(5):  635-640. 

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Ecosystem services imply the natural environmental conditions and their effectiveness formed and sustained by ecosystems and ecological processes, on which, human life relies for existence. They not only supply human with the production of ecosystem goods, such as food, forage, timber, fuel, natural fiber and pharmaceuticals, but also perform fundamental life support services, which include the purification of air and water, detoxification and decomposition of wastes, regulation of climate, regeneration of soil fertility, production and maintenance of biodiversity, and mitigation of floods, droughts, and wind and water erosions. It is recognized that ecosystem services are essential to civilization. In recent years, people pay more and more attentions on the research of ecosystem services, and ecologists and economists discuss in succession the connotations and the valuation methods of ecosystem services, which have become the frontier's topics in ecology and ecological economics. In this paper, the research advances and tendencies in ecosystem services, their economic valuation and their relations to sustainable development are literaturally surveyed and discussed.