Table of Content

25 May 1999, Volume 10 Issue 3

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Articles

Productivity distribution patterns and modeling of Pinus tabulaeformis forest in China

Luo Tianxiang, Li Wenhua, Zhao Shidong

1999, 10(3):  257-261. 

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Based on the data from 380 plots over China, the productivity distribution patterns of Pinus tabulaeformis forest are indicated in large scale. Combined with the knowledge of leaf area index distribution and plant geography, the mathematical models for the relations of the productivity to the hydrothermal and geographical factors are established. Within the normal range of P. tabulaeformis distribution (annual mean temperature 2～14℃, annual precipitation 400/300mm～700/900mm), the leaf area index was exponentially and negatively related to the annual mean temperature, which may be a mechanism for the water stress adaptation of P. tabulaeformis forest.

Height niche of some tree species in the Korean pine broad leaved forest on Changbai Mountain

Wu Gang, Liang Xiuying, Zhang Xudong

1999, 10(3):  262-264. 

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The height niche of trees reflects the complementarity of resource utilization of different tree species in varied height grade in the forest ecosystem, and is also one of the main characteristics of forest succession and cycle. The height niche overlaps are greater between those species that have similar biological and ecological characteristics, and vice versa. In gaps, the height niche overlaps between Acer mono and A.triflorum are the biggest, and comparatively small between A. tegmentosum and Carpinus cordata, A.ukurunduense and Fraxinus mandshurica, and A.tegmentosum and Ulmus laciniata. While in non gaps, the height niche overlaps between A. tegmentosum and A.mandshurica are the biggest, and comparatively small between A.tegmentosum and U.laciniata, A.tegmentosum and C.cordata, and A. ukurunduense and F.mandshurica . The height niche overlaps between Korean pine and most broad leaved trees are comparatively small, which means that, to some extent, Korean pine and most broad leaved trees are compensatory in their utilization of space and ecological resources, which may be one of the mechanisms by which they could coexist persistently. The height niche overlaps between Korean pine and most broad leaved trees in gaps are bigger than in non gaps, showing an evident that the species competition between Korean pine and most broad leave trees are increased by gaps, and that the compensating ability of resources between them are reduced by gaps. Species competition due to the large height niche overlaps is reduced by gaps, while that due to the small height niche overlaps is increased by them.

Niche characteristics of plant populations in deciduous broad leaved forest in Baotianman

Shi Zuomin, Cheng Ruimei, Liu Shirong

1999, 10(3):  265-269. 

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The niche breadths and overlaps of 14 main tree populations and 22 main shrub populations in deciduous broad leaved forest in Baotianman, Henan Province were measured using the formulas described by Levins, Hurlbert and Pianka, and the relationships among niche breadth, niche overlap and interspecific association were discussed in this paper.The results show that the niche breadths of main dominant species were greater. The Levins and Hurlbert's niche breadths of Quercus aliena var. acuteserrata and Toxicodendron verniciflnum,the main dominant species in tree layer, were 18.527, 7.488 and 0.889, 0.680 respectively,and those of Celastrus gemmatus, Vitis amurensis and Lespedeza bicolor, the main dominant species in shrub layer, were 18.964, 14.479, 13.251 and 0.908, 0.799, 0.785 respectively. The niche overlaps among the species with the same or similar environment requirements were great, while those between the species with broad niche breadth and other species were much greater. The more intense the positive association was, the larger the value of niche overlap was, and the more intense the negative association was, the smaller the value of niche overlap was.

Distribution patterns of moss species on ground in main ecosystems in Changbai Mountains

Guo Shuiliang, Cao Tong

1999, 10(3):  270-274. 

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Based on the coverages of 86 moss species in51 sites with 3305 samples on ground in Changbai Mountains, six groups of sites including Larix gmelinii-bog, turdra, Betula ermanii forest, transitional forests in sub alpine, dark conifer forest and Pinus koraiensis broad leaved mixed forest were identified using TWINSPAN. The total moss coverage of Larix gmelinii-bog, tundra Betula ermanii forest, transitional forests in sub alpine, dark conifer forest, and Pinus koraiensis broad leaved mixed forest were 26.88%, 80.94%, 25.42%, 59.83%,44.11% and 1.67%, respectively. With the decline of pH and the increase of soil water content, the total moss coverage increased. In the forests between tundra and Pinus koraiensis broad leaved mixed forest, the total moss coverage declined with the canopy coverage. The relationship between the species number (N) and their niche breadth (B) for 86 moss species in51 sites followed the model: N=74.6475×e^-20.6705×B. It indicates that the most moss species in Changbai Mountains had very narrow niches.

Physioecological characteristics of three species of pine

Zeng Xiaoping, Zhao Ping, Peng Shaolin, Yu Zuoyue, Cai Xi'an

1999, 10(3):  275-278. 

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The photosynthetic rate, transpiration rate, daily CO₂ assimilation quantity and water use efficiency of Pinus massoniana, Pinus elliottii and Pinus caribaea in hilly regions of south subtropics of Guangdong were measured. The photosynthetic and transpiration rate of test pines displayed daily and seasonal variations,with the maximum in summer and the minimum in winter. Among the test pines, P.caribaca had the highest annual average daily CO₂ assimilation and water use efficiency,indicating that is more adaptive to the local environment,and should be widely popularized in this study area.

Relationship between soil seed bank and aboveground vegetation in tropical forest of Xishuangbanna

Tang Yong, Cao Min, Zhang Jianhou, Sheng Caiyu

1999, 10(3):  279-282. 

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The relationship between soil seed bank and aboveground vegetation in several tropical forests of Xishuangbanna was studied by experimental method. The results show that at the initial succession stage of forest, there were more species of soil seed bank common with its aboveground vegetation and their seed storage, but the proportion of seeds from exotic species was gradually increased with increased forest age. The seeds in soil seed bank at mature forest stage were mostly from pioneering species outside of the communities, which would hardly germinate under closed canopy. But, when forest gaps or opens occured after the forests disturbed, these seeds would germinate rapidly, and play an important role in vegetation restoration or succession.

Biochemical characters of forest soils at Wuyishan Mountain

Zhuang Tiecheng, Zhang Yubin, Lin Peng, Chen Renhua

1999, 10(3):  283-285. 

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Studies on the biochemical characters of forest soils in Wuyishan Mt. Natural Reserve show that the rates of soil respiration, cellular decomposition and nitrification differed obviously with habitats. Soils under broad leaved evergreen forest (Castanopsis eyrei) at Xianfengling had higher rates than those under moso bamboo forest (Phyllostachys heterocyca var. pubescens) at Dazhulan. The three rates at each habitat also significantly differed with microhabitats: for respiration rate, litter layer>humus layer>soil layer; and for nitrification rate, soil layer>litter layer>humus layer; for cellular decomposition rate, humus layer>litter layer>soil layer. Among the three rates at each hibitat, there existed a definite relationship between respiration rate and cellular decomposition rate, while the nitrification rate was independent of the other two. The activities of sucrase, celluase and proteinase varied with different habitats, which were higher at Dazhulan than at Xianfengling, and decreased with increasing soil depth. Among the three enzymes, sucrase had the highest activity at all microhabitats, and the variation of its activity was greater.

Structure optimization of Paulownia-belt in Paulownia-crop integrated system

Yang Xiu, Wu Gang, Huang Dongmei

1999, 10(3):  286-288. 

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In this article, a Paulownia-wheat intercropping system was used as an example to study the relationships of wheat yield with shelterbelt structure and its coverage. The optimized structure of Paulownia-belt was formulated through a series of mathematical models. The results show that during one rotation of Paulownia, the average of relative accumulative wheat yield reached the highest (105.4) when the average of accumulative shelterbelt coverage was 10.1～ 10.9 % which is the best one. The regression equation of the optimized distance (D) and Paulownia rotation period (T) is showed as follows: D=0.600+11.042T-0.787T²⁺0.0273T³(R²=99.9%) .

Relationship between fruit quality of Fuji apple and meteorological factors

Wei Qinping, Cheng Shuhan, Tang Fang, Li Jiarui

1999, 10(3):  289-292. 

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The fruit quality of Fuji apple in various ecological regions of China and its major affecting meteorological factors were studied by investigation, laboratory analysis and multiple statistical analysis. Fuji apple fruits in the loesss plateau of Weibei and Longdong areas of northwest China, and in the Bohai Bay of Shandong Province had a high weight per fruit, and a glossy and gaily colored fruit skin; while those in mountainous region of southwest China had a dull red skin, in the former course of Yellow River had a rough and poor colored skin and in Ningxia Province had small sizes. The major meteorological factors affecting fruit quality were selected by canonical correlation analysis. The anthocyanidin content of fruits was affected mainly by annual total precipitation, and average temperature in October, maximum average temperature in July, and minimum average temperature and sunshine hours in September.

Optimal adjustment on fruit-crop intercropping model Ⅲ maize intercropping experiment

Bao Weikai, Liu Zhaoguang, Qian Nengbin

1999, 10(3):  293-296. 

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The optimized adjustment experiment on an agroforestry model of apple trees intercropped with maize in dry valley region of upper reach of Minjiang River shows that the maize varieties characterized by early or middle maturity and short bodies were suitable for intercropping under apple trees. These varieties increased the economic output by 3.9～22.0%,while decreased the competition with apple trees. The techniques of seedling in maize cores were simple and practical. All treatments of seedling in maize core soaked with different fertilizer solutions could increase the crop yield: the treatment with 3kg CaP₂O₅/50kgH₂O had the highest increase of output,up to 36.8%; those with liquid dung, 2.5 kg urea/50kg H₂O,1.5kg urea/50kg H₂O and 5kg compound fertilizer/50kg H₂Oalso increased output by over 20%; while the treatment with 2kg CaP₂O₅/50kg H₂O increased output by 16.7%. These concentrations of different solutions were suitable for growing maize seedlings in maize cores in the test region,but the soaked time with 12～15 days was too short to decrease the seedling survival. The result from cultivation pattern experiment shows that cultivation with 45000 nests/hm²,two seedlings per nest and north south direction of leaf stretching could significantly improve output.

Rational N regulation in wheat/corn high-yield farm ecosystem—Taking winter wheat-summer corn system in Hengtai county of Shandong Province as an example

Zhang Xinming

1999, 10(3):  297-300. 

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This paper deals with the interaction between chemical Nand organic fertilizers in high-yield wheat/corn farmland ecosystem, and developed a safe and rational Napplication rate.The typical cropping system is winter wheat intercropped with summer corn. In the field experiment, four rates of urea and three levels of poultry manure were applied and split-plot experiment design was used, in which the manure treatments were placed as the main plots and the urea treatments as sub-plots. Phosphate and potassium fertilizers were same for all plots. The result shows that the interaction between chemical nitrogen fertilizer and poultry manure is significantly negative, and the safe and rational Napplication rate in high yield winter wheat summer corn system was 300kg·hm^-2yr^-1 and 150kg·hm^-2, respectively.

Nutrient balance in rice field ecosystem of northern China

Luo Liangguo, Wen Dazhong, Shen Shanmin

1999, 10(3):  301-304. 

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The nutrient balance and efficiency in five rice field ecosystems were studied at the lower reach plain of Liaohe River from 1994～1996. The results show that the Ninput and output in various patterns of rice ecosystem were basically balance, little more for Kinput than output, and Pinput as twice much as its output. With rational management measures of fertilization and water-saving, the rice yield would be increased, and the nutrient efficiency would be enhanced to some extent.

Ecophysiological effect of dry cultivated and plastic film mulched rice planting

Huang Yide, Zhang Zili, Wei Fengzhen, Li Jincai

1999, 10(3):  305-308. 

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The drought-endurance of rice was different at its tillering, jointing, earing and filling stages under dry cultivation.Mulching soil with plastic film could effectively resist ground evaporation, save water as much as 60～85%, and prolong growth period 7～9 days. The tillering ability was intensified, with more 170.1×10⁴ per hectare tillers than paddy field. The number of effective ears was increased, but the grains per ear, grain setting rate and grain weight were decreased. No significant difference of grain yield was found between dry cultivation field and paddy field. Film mulching on dry cultivation field had a strong superiority at earlier growth stage, but LAI, NAR, CGR and specific leaf weight were decreased at later growth stages, with slow filling speed and low economic coefficient.

Effect of water and fertilizer on economic properties of winter wheat in Loess Plateau galley regions

Li Xiangmin, Xu Chunxia, Li Kaiyuan

1999, 10(3):  309-311. 

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Field experiment shows that in Loess Plateau galley regions, the most important limiting factor for wheat growth was fertilizer instead of water. With irrigation, fertilization had a significant positive effect on the economic properties of winter wheat, while irrigation could have a positive effect only when the fertilizer was applied.

Phosphorus and nitrogen transfers and runoff losses from rice field wetlands of Chaohu Lake

Yan Weijin, Yin Chengqing, Sun Pu, Han Xiaoyong, Xia Shouxian

1999, 10(3):  312-316. 

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Rice field wetland system is the main land use type in the high product agricultural watersheds of Southerneast China. Field experiments show that rice fields, ditches and multipond systems can effectively retain nonpoint phosphorus(P) and nitrogen (N) pollution from different land uses in a subwatershed of Chaohu Lake. The mechanisms of Pand Ntransfers and runoff losses from rice fields are mainly studied. By the analysis of Pand Ndynamics in rice fields, it was found that Pand Nloads in runoff were depended on field water level, applied fertilizer amount, precipitation, rice growth process, and height of field overflow mouth. Asimple model was built to calculate the quantity of Pand Nloads in runoff from rice fields. It shows that the total loads can reach 0.69 and 11.2kg·hm^-2 for Pand Nrespectively under the condition of applying fertilizers, which is the potential effect on Chaohu Lake eutrophication.

Changes of soil chemical properties after transferring acid sulfate paddy soil to upland soil

Li Huaxing, Zhang Xinming, Lu Weisheng, Liu Yuanjin, Li Changhong

1999, 10(3):  317-320. 

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This paper dealt with the changes of the soil chemical properties after transferring acid sulfate paddy soil to upland soil, and compared the economic profits among different land use patterns. The results show that transferring planting rice to planting sweet corns and vegetables significantly reduced soil acidity and the contents of hydrolytic sulfate, active aluminum and active iron in arable layer, and greatly increased economic profits. It was suggested that the environmental effects caused by transferring acid sulfate paddy soil to upland soil should be further studied and monitored in situ, so that, this special soil resource could be more rationally used.

Analysis on landscape elements and fragmentation of Yellow River delta

Bu Rencang, Wang Xianli, Xiao Duning

1999, 10(3):  321-324. 

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Based on the TM5 satellite images and other relevant maps, e.g., the landform, soil and vegetation maps by GIS (PC ARC/INFO3.4D), the landscape of Yellow River delta was classified into 8 types and 30 subtypes. Accordingly, with the ratio of patch perimeter to area as well as the relative area and the spatial relations of landscape types as the indexes of identifying matrix, the landscape of Tamarix chinensis-Phragmites communis saline fluvo aquic soil inclined flat was discriminated as matrix in the landscapes of Yellow River delta. The corridors were discriminated by statistics of the ratio of patch perimeter to area step by step. The analyses on landscape fragmentation at Yellow River delta by patch density show that the patch density was bigger in ecotones, and the landscape fragmentation nearby old river courses was serious.

Bryophyte community diversity in heterogeneous urban landscapes

Lin Juan, Li Huimin, Chen Chiyu, Lu Fan, Tang Lijun, Wu Qianhong, Zheng Shizhang

1999, 10(3):  325-328. 

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Bryophyte is a kind of sensitive plant that indicates the quality of environment. Based on the sampling of the bryophyte communities of five heterogeneous landscapes in Shanghai city and its suburbs, the analysis on α and β diversity related with richness, evenness and similarity shows that the diversity index of bryophyte communities in five habitats obviously appeared gradient change, which well indicated the landscape heterogeneity. the mean height of bryophytes and the ratio of large ones varied regularly with different landscapes.

Relationship between soil denitrifying enzyme activities and N₂O emission

Shi Yi, Huang Guohong

1999, 10(3):  329-331. 

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Studies of the activities of soil nitrate reductase, nitrite reductase and hydroxylamine reductase in maize growing season and their relationship with soil water content, NO₃^--N content and N₂O emission under fertilization showed that these three denitrifying enzymes had a significant seasonal variation and were influenced by soil water content and fertilization. The relationship between soil denitrifying enzymes, soil water content and N₂O emission were further investigated, which indicated that the activities of soil denitrifying emzymes could be an index to distinguish the ways of N₂O Oproductions in upland field.

Influence of temperature on functional response of Cotesia plutellae

Shi Zuhua, Liu Shusheng

1999, 10(3):  332-334. 

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The functional response of Cotesia plutellae to the increase of larval density of diamondback moth(Plutella xylostella) was examined at indoor temperatures 15℃,20℃,25℃,30℃ and 32.5℃. The results showed that the functional response could be described very well by Holling's disc equation at all test temperatures, but the parameters of the functional response differed significantly. The rates of successful attack at 25℃, 30℃ and 32.5℃ were significantly higher than those at 15℃ and 20℃, and the handling time decreased with increase temperature. After exposed to various densities of DBM 3rd instar larvae for 5 hrs, some females failed to produce eggs to parasitize any larva. The percentage of females which have parasitized at least one DBM larva increased with the increases of both temperature and host density.

Effect of different combinations of temperature and humidity on the development and fecundity of Spodoptera exigua

Xu Jinhan, Guan Xiong, Huang Zhipeng, Yu Zhaoqin

1999, 10(3):  335-337. 

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Different combinations of temperature and relative humidity(RH) significantly affected the development and the fecundity of beet armyworm (Spodoptera exigua). The combination of 26℃ and RH 80% or 94% was optimal for the development of beet armyworm. Under this combination, the hatchability of egg, the survival rate of 1～5 instar larvae, the rates of emergence, female, and female ovipositing, and the mean quantity of oviposition were 82.63～83.70%, 81.90 ～82.47%,88.00～88.03%, 90.40～91.00%, 93.36～94.17%, 95.97～96.26%, 92.77～94.16%, 0.42 ～0.43, 0.98 and 605～606 eggs/female respectively, which were all significantly higher than those of other combinations. Under combination of 32℃ and RH94%, the population's innate capacity of increase was the highest (0.225).

Utilization of carbon and nitrogen nutrients by mycorrhizal fungi in oak forest

Han Guiyun, Zhao Shuqing, He Xingyuan, Tian Chunjie

1999, 10(3):  338-340. 

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The results showed that the test fungi strains could utilize a broad kind of carbon sources, and glucose and fructose were the optimal. With Cnutrition, the average growth of fungi was 4.4 times higher than the control. Organic nitrogen was more efficient than inorganic one, with an average growth of 1.6 times higher than the latter. With inorganic Nsources, the strains grew faster on nitrate, with an average growth of 2.5 times higher than that of control, and utilized ammonium slightly poor only with an average growth of 2.2 times higher.

Fishery ecology of jellyfish at Minjiang River estuary

Lu Zhenbin, Yan Youming, Dai Quanshui

1999, 10(3):  341-344. 

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The fishery ecology of jellyfish at Minjiang River estuary was studied from May to September 1993. The peaks of density and biomass of the jellyfish appeared in June 20 and July 10, respectively. The diameter of the umbrella part ranged from 18 mm to 546 mm, averaging328.8mm. The body weight ranged from 0.5g to 9540g, averaging2877.4 g. The sexual reproduction capability of individuals with the diameter of umbrella part ranged 345～485mm was 1120.6×10⁴～3754.8×10⁴ eggs, averaging 2444.7×10⁴ eggs, and the period of sexual reproduction continued from the beginning of August to November. The diameter growth of the umbrella part and the body weight of the jellyfish could be calculated respectively by the power equation and power exponential equation: Φ_t=12.1337 + 17.7048t + 3.1385 t²-0.2049t³+0.00302t⁴, log_eW_t=-0.5749+1.4818t-0.0771t²+0.00129t³. From the standpoint of biology and economics, the optimum date for starting fishing may be in July 20, with the optimum diameter of the umbrella part by 465.8mm. The optimum date and size of actual beginning fishing were also discussed, which would be important for the conservation and exploitation of the resources of jellyfish, and for the increasing economic effect.

Influence of environmental conditions on growth of Hydrodictyon reticulatum

Wang Zhaohui, Luo Yumin, Jiang Tianjiu, Lin Qiuqi, Qi Sang

1999, 10(3):  345-349. 

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Studies on the relationship of Hydrodictyon reticulatum growth with temperature, light intensity and nutrient concentrations showed that H.reticulatum could tolerate a wide range of temperature (10～35℃), light intensity (300～5300Lx), and nitrogen and phosphorus concentrations (1.0～84.0mg N·L^-1 and 0.05～3.72mg P·L^-1 respectively). Its optimal growth was at 25℃,≥1300Lx, 16.8～50.4mg N·L^-1, and 0.744～2.23mg P·L^-1. Low temperature was beneficial to H.reticulatum to tolerate low irradance and low nitrogen and phosphorus concentrations.

Suspending particular matters of shrimp culture in enclosure ecosystems

Liu Guocai, Li Deshang, Lu Jing, Chen Zhaobo, Dong Shuanglin

1999, 10(3):  350-352. 

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Studies on the suspending particular matters of shrimp culture in five enclosure ecosystems show that the concentration of total suspending particular matter varied from²0.83 to 172.50mg·L^-1,with an average of 72.26±39.87mg·L^-1, among which, the organic particular matter accounted for 62%, while the inorganic particular matter was 38%. In the organic particular matter, both particular detritus and bacteria accounted for 98%, while plankton was 2% (Phytoplankton biomass was 4.50 times higher than that of zooplankton). There existed a significant correlation between the concentration of total particular matter and water transparency depth.

Soil sampling error in agricultural environment

He Liyuan

1999, 10(3):  353-356. 

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Acomprehensive study on soil sampling error was conducted based on39 sampling plots of 8 different land use types with 25 soil physical and chemical parameters. The accumulative sampling error of different land use types was in order of pond sludge>plot margin>home garden>wood land>commercial vegetable plot>upland field>paddy field>beach plot.Among all test parameters, Cl^- was of the biggest smpling error, with a mean error of more than70%. The next one was available P, with a sampling error over 30%. The sampling errors for available Kand total Swere also above 20%. The parameters with the smallest sampling error were related with soil parent materials, which included various heavy metal elements, total P, total K, total Mg, pHand sand, and their sampling errors were less than10%. There were 11 parameters with 10～20% of sampling errors, such as water content of two granule soils, CaCO3, silt, clay, organic C, total N, total Na, total Ca, total B, and total As. The test parameters could be classified into 3 types by cluster analysis, which objectively reflected the impact of human's activities on the distributtion consistency of soil physical and chemical characteristics.

Humidity control in biological experiments: modified device and methodology

Feng Mingguang, Xu Qian, Xu Junhuan

1999, 10(3):  357-361. 

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Relative humidity is an environment factor that significantly affects biological experiments, but is difficult to precisely control. Amodified device for easy control of the humidity in regular thermal and light growth chamber was described in this paper. The device included three parts: 1) air pump; 2) three pipe collected containers of salt solution for producing expected humidity; and 3) a perspex chamber, in which, experimental materials can be placed. The modified device worked well for humidity control with an error of only 1%, while a digital data logger was used to monitor the relative humidity controlled by saturated solution of sodium tartrate every three minutes for 6 h at 20℃, which was supposed to yield a 92% r.h. at that temperature. Varying concentrations of sulfate acid were tested as humidity control agents at 5～35℃, with each yielding a stable humidity in the perspex chamber regardless of temperature. The stability of the humidity control system was also discussed when the solutions of sulfate acid were used as humidity control agents.

Pb concentration and distribution in main tree species on both sides of highway in suburbs of Nanjing City

Ruan Honghua, Jiang Zhilin

1999, 10(3):  362-364. 

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This paper studied the Pb concentration and distribution in main tree species on the both sides of National Highway 312 in suburbs of Nanjing City. The result shows that the Pb concentration differed with same organs of different tree species and different organs of same species. The Pb content in loblolly pine was comparatively higher than that in Chinese fir and oak. The range of Pb pollution from tail gases emitted by automobiles was distributed within 100m apart from the highway, mainly within 40m. The Pb concentration in forest soils, especially in 0～20cm soil layer, was decreased significantly because of the soils covered by forest vegetation, indicating that the forest stands effectively decreased the Pb pollution in soils. The Pb adsorption rates by different organs ranged from 18.0% to 28.1%, with the highest by leaves. Comparing to other trees, loblolly pine had the highest adsorption rate.

Ecosystem services and corresponding protective strategies

Sun Gang, Sheng Lianxi, Zhou Daowei

1999, 10(3):  365-368. 

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This paper expounded the definition,meaning,and research status of ecosystem services, compared the services of natural and artificial ecosystem, and put forward the protective strategies and approaches of ecosystem services. Ecosystem services are those ecosystem products and functions that contribute to human survival and its life quality. The opening of ecosystem is the basis and premise of ecosystem services.There are many obstacles,such as limitation of knowledge scale and lower living standard,in the protection of ecosystem services.Distinct differences exist between natural and artificial systems,the latter having no buffers and insurance.Non governmental behavior,governmental behavior,and economic instruments are the strategies and approaches to protect ecosystem services.Ecosystem services which must be protected strictly are vital to the sustainable utilization of the earth and the sustainable development of human society.

On village ecology

Zhou Daowei, Sheng Lianxi, Wu Zhengfang, Sun Gang, Gao Wei

1999, 10(3):  369-372. 

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Urban ecology has gradually developed to a commonly confirmed branch of ecology, but the conceptual framework of village ecology has not be constructed. In this paper, village ecology is defined as a branch of ecology which studies the formation, structure and behavior of village as well as the objective entity of it and its environmental background. Village is a space settlement unit of human with the features of definite age structure and population, household as its composition unit, land as management object, and corresponding living things (livestock and crop) as main valued resources. Apart from spacial and biological meaning, village relates directly to landscape elements and resource indexes such as geological locality, topography, climate, soil and vegetation. Meanwhile, village is connected with many other complicated factors,e.g., historical tradition, social custom, and so on. The significance of village ecology is to reveal the relationship between village and all its related factors,and to guide the rural construction.

Landscape planning: concept, origin and development

Zhang Huiyuan

1999, 10(3):  373-378. 

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The various understandings of the concept of landscape referred in the fields of geography and landscape ecology are analyzed and summarized in this paper. The differences between landscape and land, environment and scenery are also distinguished. Based on the studies above, this paper discussed the implication of landscape planning and the concept of landscape which it is based on. Moreover, this paper suggests that the emerging and developing of landscape planning should be divided into three periods, which are the periods of originating in the mid late 1800s to early 1900s, shaping in1950s 60s and developing accompanying with landscape ecology since 1970s, respectively.

Role of root exuded organic acids in mobilization of soil phosphorus and micronutrients

Lu Wenlong, Cao Yiping, Zhang Fusuo

1999, 10(3):  379-382. 

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As a kind of adaptive mechanism, many plants can increase organic acid exudation in response to nutrient stress, especially Pdeficiency. This paper discussed the root exuded organic acids of different ecotype plants under nutrient stress. The kinds and amounts of root exuded organic acids under Pdeficiency were highly related to surrounding soil environment. The organic acids exuded by root under nutrient stress were able to mobilize soil phosphorus and micronutrients, and to relieve aluminum toxicity. The paper also discussed the possible mechanism of soil nutrient mobilization and aluminum detoxification.

Evaluation on methods in quantitatively sampling and counting crustacean zooplankton

Gu Xiaohong

1999, 10(3):  383-384. 

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Indoor and field experiments show that there existed a significant difference between the counting results of conventional and filtering sieve methods for sampling and analyzing crustacean zooplankton. The amount of crustacean zooplankton by conventional method was lower than that by filtering sieve counting. Statistical analysis shows that the difference was significantly notable. This paper discussed the possibility for causing the difference. The conventional method should be improved, otherwise, it would lower the accuracy of water quality evaluating based on quantitative index of crustacean zooplankton.