Table of Content

10 December 1997, Volume 16 Issue 06

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Study of the Birds Community Structure in Different Succession Period of Korean Pine Forest

Chang Jiachuan, Lu Changhu, Liu Bowen, Xu Qing

1997, (6):  1-5. 

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Korean pine forest has three typical succession periods: Clearcut area (including fired area), natural second-growth forest and natural forest. Birds community structure changed with succession periods: (1) birds species are different in 3 periods, every period has typical species; (2) birds species changed with succession period of the forest; (3) birds density is different in different periods; (4) more and more parts of bird species distributed in upper level with succession period; (5) Species diversity index in the natural second-growth forest is the highest.

Studies of Ecological Effects of Sod Culture in Citrus Orchard

Li Guohuai, Zhang Wencai, Liu Jihong, Hu Dewen

1997, (6):  6-11. 

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The experiments to study the ecological effects of sod culture on satsuma (Citrus unshiu Marc.cv. Ramei) were carried out in citrus orchard in 1993-1995. White clover (Trifolium repens L.)and bahia grass (Paspal umnotatum Flugge) were planted as sods, they were cut to cover the soil in summer and used as basic manure in winter.The treatments were as follows: (1) Clean cultivation (CK), (2) White clover,(3) Mixture of white clover and bahia grass, (4) Bahia grass. The studies showed sod culture resulted in decrease of temperature of soil and air in the tree canopy and increase of soil water content and the air realtive humidity under drought conditions. After 3-year sod culture, the soil organic matter, hydrolytic N, effective P,K,Fe,Cu and Zn were increased in comparison with clean cultivation. Leaf N and Fe content of citrus trees in treatment No.2, and leaf P and K in treatment No.3, 4 were also increased . From July to October,the leaf photosynthetic rate of citrus trees in sod plot was raised. Furthermore,the sod culture was effective to increase the percentage of fruit set and yield by reducing the abnormal fruit drop during the unusual temperature and drought period.

Effects of Replant Soil on the Growth of C. lanceolata Seedlings

Ma Yueqiang, Liao Liping, Yang Yuejun, Wang Silong, Gao Hong, Chen Chuying, Lin Gengyou

1997, (6):  12-16,21. 

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Effects of water extracts of soil collected from replant woodlands of C.lanceolata (first rotation, second rotation) and mixed plantation soil of C.lanceolata and Michelia on the growth of C.lanceolata seedlings were studied. The results indicated that some allelopatic substances existed in replant soil of C.lanceolata. Extracts of replant soil significantly inhibited the growth of C.lanceolata seedlings,and reduced chlorophyll contents, length, numbers and weight per cm of new branches(p<0.05). The residues of decomposed root might be one of the possible resources of allelopatic substances in replant soil. The mixed plantation of C.lanceolata and Michelia could reduce the toxicity of allelopatic substances on the growth of the C.lanceolata seedlings.

Preliminary Studies of Carbon Cycling in Three Types of Forests in the Hilly Regions of Southern Jiangsu Province

Ruan Honghua, Jiang Zhilin, Gao Suming

1997, (6):  17-21. 

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The carbon content distribution and storage in three of types forest have been investigated in Xiashu forest farm.The results showed: (1)The carbon content varied with different tree species and different organs of the same tree species.The carbon content in the Chinese fir, Loblolly pine and Oriental oak trees were 51.0%,54.5% and 49.9% respectively.(2)The accumulation of carbon in Loblolly pine, Chinese fir, Oriental oak stands were 5.79t·ha^-1·yr^-1 ,2.46t·ha^-1·yr^-1 and 2.46t·ha^-1·yr^-1 respectively, (3) The carbon storage in the forest ecosytems (including 0～80cm soil layer) was 163.96t·ha^-1 in Loblolly pine stands, 174.62t·ha^-1 in Oriental oak stands and 117.68t·ha^-1 in Chinese fie stands.About 32.9%～43.3% of the total carbon storage was in the 0～80cm soil layer, while about 50%～60% of the carbon storage of the 0～80cm soil layer was in the 0～20cm soil layer. (4)In the three forest ecosystems, about 50% of the total carbon storage was in the stemwoods. Therefore, the carbon oxides released from the harvest of the forest would be very little if the forest regenereted in time and the fellings were not cleanly burned after the harvest.

Phytomass and Net Primary Productivity of the Grassland in Hong Kong

Guan Dongsheng

1997, (6):  22-26. 

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Phytomass and net primary production (NPP) of the grassland consisting of Ischaemum spp.+ Arundinella setosa + Eulalia speciosa community have been estimated by harvest method.The results showed that:(1)Above ground phytomass including standing dead matter and litter,was 589 g穖^-2 ,of which living phytomass,standing dead matter and litter comprised 63%,26% and 11% respectively. Under ground phytomass was 475 g穖^-2 ;(2)Above-ground live phytomass showed a significant seasonal pattern.The grasses sprouted in early spring and their phytomass increased steadily until September,then the live phytomass began to decline;(3) The above-ground current phytomass was not obviously related to monthly rainfall but related to temperature,evaporation and bright sunshine in the study area with plentiful rainfall;(4)Estimated by aggregate peak phytomass(live+dead),470g穖^-2穣r^-1 was considered as the net above-ground primary production (NAPP) of the grasses. The NAPP of the grasses estimated by aggregated peak phytomass(live+dead) was 36% higher than peak phytomass (live only) and 27% higher than aggregated peak phytomass (live only).NPP of the grassland was 763g穖^-2 .

Fertility and Elements Bio-Cyclings of the Caragana Microphylla L Forestland in the Rolling Loess Region

Liu Zengwen, Li Yasu

1997, (6):  27-29,51. 

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The results of the present study showed that Caragana microphylla L. could improve the soil fertility. The element contents of N,P,K in C.microphylla forestland were 50.47%,83.48% and 103.88% respectively, which were more than those of the bare slopeland. There was no obvious difference of fertility among the forestlands with different planting time ,but with increasing of the forest age after cutting, fertility of the forestland was improved slightly. In the plant of C.microphylla, Contents of the fertility elements in living leaves were higher than in roots and branches,trunks. The dead leaves had lower content of the fertility elements than the living leaves. The growth of C.microphylla needs more N than K and than P. It needs about 18.69kg N,1.59 kg P and 6.25kg K to produce 1000 kg dry material. Absorption ratio of elements by C.microphylla from the forestland were N(0.4240%) higher than P(0.0123%) and than K(0.0065%).However, the return ratio through bio-cycling were N(0.30) lawer than P(0.39) and than K(0.48).The results indicated that the N₂-fixation of nodule was the main cause that kept the forestland without shortage of N content under great growth absorption.

Environmental Immigration of Pumping Water Irrigation Project for Poverty Reducing in Ningxia and Assessment of Its Effects

Wang Mou, Sun Libo, Ma Ke

1997, (6):  30-35. 

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Based on assessment of environmental capacity of immigration and concern for the environmental protection and sustainble development,the effects of the pumping water irrigation project for poverty reducing in Ningxia on environments were analysed.Influcnces of the project on the social economy in the future were predicted and strategy for sustainble development in the related areas was also proposed.

Potential Effects of Climate Change on Agricultural Insect Pests

Zhang Runjie, He Xinfeng

1997, (6):  36-40. 

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Climate change arisen from increasing level of atmospheric greenhouse gases would be likely to have significant effects on agricultural insect pests. It would result in changes of geographical distribution, overwintering, population growth rates, the number of generations, crop-pest synchrony,interspecific interactions and risk of invasion by migrant pests. Future situations of some important insect pests were discussed.

Plant Compensation for Animal Herbivory——Factors Affecting Plant Compensation

Yuan Baozhong, Wang Jing, Zhao Songling

1997, (6):  41-45. 

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There are various compensatory responses of plants to animal herbivory. Sometimes,plants produce more biomass and seeds,increase growth rate and enhence their fitness. The factors affecting plant compensation are both endogenous and exogenous. Endogenous factors include:photosynthetic enhancement,reallocation of available assimilates,changes in canopy architecture and leaf morphology and delay of senescence following defoliation.Exogenous factors contan: nutrient availability,intensity and timing of defoliation, distribution of animal,and other environmental stressed.Therefore, there is a limitation of plant compensation.

Developement of Niche Concept and Its Perspectives : A Review

Zhang Guangming, Xie Shouchang

1997, (6):  46-51. 

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Niche theory is important both in theoretical and applied ecology,but a generally-accepted definition has not been established yet. During the past century, three ecologists have made great contribution to development of the niche concept. Grinnell's (1917,1924, 1928) “spatial niche”, Elton's (1927) “functional niche” and Hutchinson's(1957)“n-dimentional hypervolume niche” have been the major categories of the definition of niche. The present paper reviewed the development of niche concept and analysed the problems that have confused and bothered ecologists for almost 100 years.Finally, a new definition of the niche concept was proposed. Niche can be described as the functional role that a particular species plays in all or a special stage of a given species' invasion, colonization, propagation, development, decline, and extinction process'. Niche theory can be applied to the conservation of endangered,threatened and declining species in the 21st century.

Ecotones and Ecological Flows

Wang Qingsuo, Feng Zongwei, Luo Juchun

1997, (6):  52-58,66. 

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ne of ecotonal functions is its influence on ecological flows, which are the flows of materials, energy and organisms across landscapes. The theoretical foundations for understanding the ecotones and ecological flows include cellular membrance theory, percolation theory, spiralling concept and factor analysis. Many results of the studies showed the relationships between the ecotones and ecological flows. Hunan activities were main factor influencing changes of the ecotones and ecological flows.

Effect of Rare Earth La on the Wintersweet Harmed by Simulated Acid Rain

Zhou Qing, Huang Xiaohua, Wang Dongyan, Shao Aihua, Wu Bo

1997, (6):  59-61. 

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When 15mg稬^-1 LaCl₃ was used to spray wintersweet three times ,it reduced the damage effect of simulated acid rain at pH 2.5. It was considered that the effect of LaCl₃ on the wintersweet was realted to following factors.(1)Raising photosynthetic rate and chlorophyll content;(2)increasing catalase activity;(3)decreasing malondialdehyde content; (4)reducing cell membrane permeability and (5)keeping stability of pH value of cell juice.

The Models of Relationship between Height Growth of Picea mongolica and Site Conditions

Zheng Yuanrun, Xu Wenduo

1997, (6):  62-66. 

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Stepwise regression analysis and multiple numeric theory were used to analysis the relationship between height growth of Picea mongolica and the site conditions, and the multiple models of spruce growth are: y=8.0031+0.2087p 5+0.1286p 6, y=7.7836-7.9944s+0.6686a. The results showed that seedling tree height growth of the spruce on sandy land was closely related to the precipitation in May and June, however the relation to the temperature in June was not so significant. Precipitation, temperature and their combined conditions in main growth seasons were closely related to growth of the spruce. The results of multiple numeric theory analysis indicated that the position of slope and age of plants were also main factors to effect the growth of the spruce. Site conditions, age of plants and precipitation in May and June, temperature in June should be paid special attention to in management and introduction of the spruce to other area on sandy land.

Discussion on Ecological Control of Soil Salinization

Wang Chunyu

1997, (6):  67-71. 

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Owing to large areas and continuous spreading of salinized soil in the world and difficulties in amelioration of the salinized soil, control of salinization of the soil became an ecological challenge that perplexed the mankind.The basic way to prevent and control soil salinization is comprehensive ecological amendment, including harnessing a valley effectively,washing soil salt,fertizing soil with organic matter and planting rice etc.Therefore, the salinization geochemistry is an inportant aspect in the ecological control study.

Ecological Problems of Sustainable Development in Yunnan Province

Wu Yushu

1997, (6):  72-76. 

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The ecological problems that effect on sustainable development in Yunnan province,especially the problems of natural resources and the Dianchi Lake pollution were discussed in the paper.Three aspects were included: (1) Forest sustainability and biological diversity protection;(2) Sustainable utilization of resources and sustainable development;(3)Environment protection and sustainable development.