Both local population and metapopulation dynamics were simulated by a model.The results indicate:(1)The extinctive time of a metapopulation increases first and then decreases as the number of reserves increases.That is,an intermediate reserve number is optimal for the survival of metapopulation.(2)The optimal number of small reserves established in a certain reserve was affected by the total area.This implies nature reserves of a certain area should be established to form a network consisting of several relatively small reserves rather than a few very large ones or many very small ones.
In this paper,the allelopathy of aqueous extracts from different organs of Sonneratia apetala on the seed germination of S.caseolaris and S.apetala were studied.The following results were obtained:1)Aqueous extracts from different organs of S.apetala inhibited the germination of S.caseolaris.At high concentration,the germination of S.caseolaris was significantly inhibited;2) Aqueous extract from S.apetala roots inhibited the radicle length of S.caseolaris.At high concentration the radicle length was inhibited significantly,while with decreasing concentration,the inhibitory effects got weaker.Applied with the extracts of S.apetala branch,leaf and fruit,the radicle length of S.caseolaris was significantly inhibited at high concentration;while with decreasing concentration the inhibitory effects got weaker and even turned into stimulating effects.3)Applied with the extracts from different organs ofS.apetala,the germination orS.apetala was stimulated at low concentration and inhibited at high concentration.4)At high concentration of aqueous extract from S.apetala fruit,the radicle length of itself was inhibited significantly,while with decreasing concentration the inhibitory effects got weaker.Applied with the aqueous extracts of S.apetala branch,leaf and fruit,the radicle length of S.caseolaris was stimulated at low concentration and inhibited at high concentration;5)As to the inhibitory effects on the germination and radicle length of S.apetala and S.caseolaris,the effects of aqueous extract from Sonneratia apetala fruit were stronger compared with that of other organs.
When the thylakoid membranes of brown alga Undaria pinnatifida were solubilized with DMG and subjected to PAGE, eight pigment-protein complexes were resolved.Both CP Ⅰ a and CP Ⅰ contain a polypeptide of 66 kDa,and they have a long- wavelength fluorescence emission peak at 715 nm at 77 K,the excitation spectra shows CP Ⅰ a is fucoxanthin-chla/c-protein complex and CP Ⅰ is chla-protein complex.CPa contains 51,37,34 and 20 kDa polypeptides,its fluorescence emission maximum at 77 K is at 683 nm,the excitation spectra shows that CPa is a fucoxanthin-chla/c-protein complex.The other five complexes are related to LHC,they all present a major polypeptide component of 20 kDa,the spectra characteristics of LHC1 and LHC3 are similar,they are all fucoxanthin-chla/c-protein complexes,LHC2,LHC4 and LHC5 are chla/c-protein complexes.
Acute toxicity of DMS to fish,alga and aquatic crustaceas was studied in order to evalue the effects of DMS on marine organisms and ecosystems.Results showed that DMS was toxic to aquatic organisms.The 3h,6h,9h,12 h and 24h LC50values of DMS to Gambusia affinis were 34.1,23.4,22.4,20.2 and 19.1 mg·L-1respectively.The 6h,9h,12 h and 24h EC50values of DMS to Ceriodaphnia reticulata were 47.7,21.4,18.0 and 12.3 mg·L-1 respectively.The 96h IC50value of DMS to the growth of Platymonas elliptica was 18.3 mg·L-1.From the result,we suggest that DMS in natural level has some toxic effects on aquatic organisms,but with no significant acute toxic effects.
The trophic state and plankton distribution were investigated in Hedi reservoir in 2000.The TLI(trophic level index) showed that the reservoir was meso-eutrophic.The abundance of phytoptankton in flood season and dry season were 1 950.5～3 509.7×104 cells·L-1and 130.5～231.3×104 cells·L-1respectively,and the proportion of Microcystis sp.and Phormidium sp.(Cyanophyta) in phytoplankton abundance were over 83%.In both flood season and dry season,the phytoplankton community structure is Cyanophyta-Chlorophyta-Bacillariophyta.The dominant species are Microcystis sp.and Phormidium sp.in the two seasons.The sub-dominant species were Gloeocapsa sp.and Oscillatoria sp.(Cyanophyta),Chlamydomonas sp.(Chlorophyta),and Melosira granulata(Bacillariophyta)in the flood season.However,the sub-dominant species were Aphanizomenon flos-aquae(Cyanophyta) and Melosira granulata(Bacillariophyta)in dry season.All above these species are eutrophic indicators.The species of zooplankton in the Hedi Reservoir were rare but the abundance very high.In the flood season,the Nauplii and Copepodite of Copepoda were abundant in the reservoir.The predominated species were Keratella valga,Trichocerca elongata,Brachionus forficula(Rotifer)and Bosmina longirostris(Cladocera)in the flood season.In the dry season,however,the abundance of Nauplii were highest in zooplankton but the abundance of Copepodite descended rapidly.The predominated species were Bosmina longirostris(Cladocera),Mesocyclops leuckarti(Copepoda)in dry season.The predominated groups in the two seasons were those species with a wide-ecological spectrum and/or were all organic matter-resistant.
Effects of any two dements of S(Na2SO3),Se(Na2SeO3)and Te(Na2TeO3)in S family on the growth of Spirulina maximum and S.platensis were investigated.It was shown that Se and Te had toxicity to two species of Spirulina,and toxicity of Te was stronger than that of Se obviously.In a specific range of concentration,sulfur could detoxificate the toxicity of Se and Te to a certain degree,but in high concentration this function declined,and Se also could detoxificate the toxicity of Te.But at the higher concentration,toxicity of Se and Te cooperated with each other.S,Se and Te could bring different effect on these two species obviously.To S.maximum,as increasing of S(Ⅳ)concentration the detoxifcation function to high concentration of Se enhanced. When S(Ⅳ)concentration reached 600 mg·L-1,it detoxifcated toxicity of 600 mg·L-1Se(Ⅳ)completely.But detoxifcation function of S to Te was weak.At the anaphase of S.maximum growth,25 mg·L-1Se could detoxifcate the toxicity of Te partly.To S. platensis,detoxifcation function of 50 mg·L-1S(Ⅳ)to Se and 200 mg·L-1S(Ⅳ)to Te was maximal,but it couldn't detoxifcate toxicity of 600 mg·L-1Se 或 200 mg·L-1Te completely.The detoxifcation function of 50 mg·L-1Se to Te was maximal.But the toxicity of 200 mg·L-1Se cooperated with Te.
The experiments of Macrobrachium rosenbergii larvae of three culture populations,Guangdong(G),Shanghai(S), Jiangsu(J)populations and one wild population,Vietnam(Y)population,were carded out to study the resistance to abruptly increasing temperature.The results showed that the environmental adaptation of Guangdong and Vietnam populations were better than that of Shanghai and Jiangsu populations.
A field research was conducted at the garden of fruit institute of Maoming City,Guangdong Province in 2000 and 2001, in order to study the effects of chemical regulators,which mainly contain the potassium chiorate(KClO3),used in different seasons on flowering and fruit quality of longan(Dimocxarpous Longanna).The experiments indicted that the effect of inducing flowering(%) were significantly difference in different seasons.The effect of inducing flowering(%)of the chemical regulators in dried season were better than that in wetness season.The off-season longan fruit quality is different from the usual harvest fruit.An improvement in fruit quality was observed in fruit harvesting in later spring and early summer.Bigger fruit weight,higher ration of eatable part, less weight of seeds pit and lower acid degree were observed in later spring and early summer longan fruit.It suggest that using the chemical regulators in early autumn and harvesting fruit in later spring or early summer be suited to the off-season longan fruit production in the research region.
According to different land use systems(forest land,cropland,orchard land,rice field and bare land)and different soil types,soil samples were obtained in different regions of Guangdong Province,and amount of microbes,including bacteria,fungi and actinomyces,and soil nutrients were analyzed.The experimental data showed that there was a positive relationship between soil microbial population and soil fertility status,and the total amount of microbes was 1.0×106 ind·g-1dry soil or more in most soils of Guangdong province.Differences of soil microbial amount were found in different areas,soil microbial amount in east region(the number of Chaoshan region is 7.77×106 ind·g-1dry soil)were higher than those in west region(the number of Zhanjiang region is 1.6×106 ind.·g-1dry soil),it was lowest in Guangzhou area(the number is 1.35×106 ind.·g-1dry soil).There also was difference of soil microbial amounts among different land use systems,i.e.total microbial amounts from high to low were in forest land> vegetable planting land>rice farmland>orchard land>dry cropland>bare land.The microbial biodiversity had a decreasing trend in most soils of Guangdong province.
An investigation on aquatic birds of Futian wetlands in Shenzhen Bay was made in recent 10 years.The results show that the species of aquatic bird tend to decrease.In the winter of 1999～2000,contrasting to the records five years ago,1 Catalogue,1 Family 13 Genera,28 species have disappeared,and 1 Catalogue,4 Family 19 Genera,45 species have disappeared contrasting to the records ten years ago.However the number of individual appears to be increasing.The maximum number of aquatic birds was 1 051 in the winter of 1991～1992,but it was 20 467 in the winter of 2000～2001.The annual dynamics of total number of water birds in 1994 were consistent with that in 2000:maximal in January,tend to decreasing from October to December.By means of analysing the data,some suggestions on recovering and improving the ecological environment of the wetland was made.
The animal gut morphology is closed related to food habit,food quality and energy demand.The seasonal changes in length and weight of total digestive tract and separate parts of digestive tract in Rattus norvegicus,which lived in add environment of Xinjiang were determined.The results showed that the length of whole digestive and small intestine and large intestine had significant seasonal variations,which were higher in spring and winter than in autumn and summer.We also discovered that the length and weight of stomach of the species captured in Alashankou region had significant seasonal variations.
It was the long term human activities that built the modern landscape patterns in Eastern Liaoning Mountainous Regions. In the historical period,because the human activities were limited,the original matrix was not changed,which made the original forest landscape remain.Round about liberation and during the Great Cultural Revolution,the frequent human activities changed the original forest landscape greatly and brought a series of environmental and ecological problems.Since 1990s,with the rising of ecological agriculture,a new kind of semi-natural forest landscape pattern has been in embryo,which corresponds with the sustainable economic development.It presents the expansion of the forest matrix,the sustainable increase in the steady artificial forest patches and the decrease in the unsteady farming patches.But because of the increase in human habitat patches and artificial corridors,the stability of the landscape patterns will still be threatened.
Keys are presented that incorporate all the known bolete genera of tubulate and lamellate taxa occurring in China;28 genera so far known by the authors are listed and their positions in the taxonomic system are indicated according to Kirk et al.(2001). They are offered in the hope that the information will be helpful to better understanding the Chinese bolete mycoflora and diversity, and the keys will be improved by the users of insight.
The basis,importance and urgency to establishment of Fenghuang mountain provincial nature reserve area located in the southern part of Guangdong province were discussed.The conditions of geographical region,natural environment,social economy and natural resources for establishing nature reserve area were also analyzed.Proposals for establishing the function zone and planning principles,along with suggestions for personnel organization and the policy and mode of management were put forward.Finally,the author evaluated the benefit and the budgetary estimate of the investment to establish and manage Fenghuang mountain provincial nature reserve area.
Organisms in the aeration were examined daily under the microscope during the processing of pharmaceutical waste water by SBR treatment.The reasons of unstable processing efficiency were put forward and methods to promote SBR were suggested.
The feed transforming efficiency of Monopterus albus fed with the larva of Tenebrio molitor L.was preliminarily studied.The results showed:with the same stock density 1.5 kg·m-2,the dry biomass mean transforming efficiency was 11.3% and the energy mean transforming efficiency was 7.8% under condition B(Different strains with some individuals in bad condition were cultured under temperature 24±4℃,changing water every 7 d).But under conditions A(healthy individuals were cultured under temperature 17±3℃ in quiet circumstances,changing water every 2 d or 3 d),the two indexes were 20.1% and 13.9% respectively, and the transforming efficiencies of N and P were 22.0% and 28.9% respectively.Monopterus albus had lower growth rate if it was fed with the larva for a long time.It was appropriate that Monopterus albus was fed with a vary type of lively baits or with the fodders made up of compound feeds and lively baits in practice.
Arbuscular Mycorrhizal Fungi(AMF)exist in almost all kinds of soils and form symbiosis with nearly all families of the angiosperms.Most of the crops,fruit trees,vegetables and ornamental plants can form arbuscular mycorrhizae.AMF can enhance plant growth by increasing uptake of nutrients and water,increase plant resistance to several soil-borne root pathogens and tolerance to adverse circumstances.AMF also play an important role in conservation of soil and are thus regarded as a 'biological fertilizers'. Inoculation with AMF improves the growth and primary establishment of seedlings.For the improvement of degraded ecosystem and sustainable utilization of forest and agricultural resources,AMF could be used as a biofertilizers in the future.
The recent advances in research on constructed wetlands,including the development history and present condition,the advantages and weakness,the classification and the mechanisms of wastewater treatment were reviewed.
The characteristics of exotic plant invasion and their consequences in China were reviewed.Multiple Ecosystems were more sensitive to the invasion of exotic plants.Exotic plants have invaded various areas and habitats,so they account for high proportion of flora in China.Plant invasions bring about damage not only to development of economy,but also to eco-safety and social stability.It is urgent to carry out research on invasion biology and invasion ecology systematically to investigate invasion mechanism of exotic plants,and then formulate laws and rules to prevent invasion by exotic plants.
Categories including nitrogen fixing bacteria,phosphate-solubilizing bacteria,photosynthetic anoxygenic bacteria of plant-growth-promoting bacteria,which isolated from rhizosphere of mangroves were presented,and their application prospect in restoration of mangrove ecosystem was discussed.
Ecosystem health is a new field based on the integration and infiltration of natural science,social science and health science.It deals with implementing strategies in natural resources,environmental management and the relationship between ecosystem health and human health.Ecosystem health is an important premise for human health and the sustainable development of society.As recognition about the dependence of human health and well-being on ecosystem functions and services is being strengthen, it is necessary to understand the linkages and interdependencies among biodiversity(the species that make up the structure of ecosystems)and ecosystem health(the functioning and performance of the ecosystem)and human health(the functioning and well-being of the dominant species in the current global ecosystem).Understanding these linkages is a necessary condition for achieving globar sustainability.In this paper,the origination and advancement of ecosystem health are reviewed as well as the concept and main research contents.The effect of changes in biodiversity on ecosystem health under the human alteration of global environmental change is reviewed.
In this paper,the reasons for eutrophication,the situation of algae pollution,the species,the main factors leading to the algal blooms and the negative effect of the different alga on the water treatment process were discussed.Enhancing coagulation, adsorption of activated carbon and oxidation of potassium permanganate were the three methods usually used,which inprove the removal efficiency of alga.New methods to prevent the hazards of alga are proposed based on the development of researches on water purification process.
