Two or more species can live in the same patch network without any interactions among the respective metapopulations.More interestingly,interspecific interactions might affect the rates of migration,extinction and colonization,in which case interspecific interactions modulate metapopulation dynamics of the species concerned.Related researches are mainly concerned on interspecific competition,predator-prey dynamics and the creation and maintenance of aggregated spatial distributions of species in the absence of any environmental heterogeneity.In this paper,we evaluate progresses on competition,dynamics of predator-prey systems and complex spatial dynamics at the metapopulation level.
The characteristics of population variation and species diversity in succession processes of Karst vegetation in Yangshuo in Guangxi have been studied by a spatial series representing temporal series.The results showed that,with the development of succession,shade-tolerant populations and tree populations increasedt,he replacement of dominant species took on certain continuity,the dominant species of the process have hided in the former community;in the process of succession the species richness revealed the tendency of herbosa<deciduous broad-leaved forest<brush<evergreen-deciduous broad-leaved mixed forest in every succession stages,the richness in shrub layer was highest than other layers,and the community evenness in deciduous broad-leaved forest stage was highest among four succession stages.
In order to explore the conservation strategy and resource acquisition of Epimedium brevicornum.The variations of clonal architecture and ramet population characteristics of E.brevicornum growing at the open land of forest edge,forest and forest understory were studied by field investigation and laboratory analysis.The influences of environmental factors on the clonal architecture and ramet population characteristics were analyzed.The results indicated that the branching intensity,spacer length,branching height,length of rhizome and ramet population density were different among three habitats.There were signficant regressive relationships between them and relative light intensity,soil water content of habitats.It implied that the relative light intensity and soil water content of habitats mainly influence the clonal growth of E.brevicornum.The clonal growth depended on the rhizome under ground,and has morphological plasticity.These results were discussed in the context of resource acquisition strategy by clonal plants.The response of clonal architecture and ramet population characteristics to resource heterogeneity has important ecological implication.Protect the rhizome under ground and reduce the disturbance by human being,it's an effectual way to keep the continuable utilization of E.brevicornum which lived in field.
Beilun,which is located in Ningbo Zhejiang province,contains abundant plant resources.There are 712 species or varieties vascular plants of 158 families and 454 genuses.Among these plants,276 species are medicinal plants,95 species are timber plants,87 species are ornamental plants,60 species aretextile plants and 55 species are defending plants,52 firewood plants,48 lipidic plants,42 forage plants,38 wild fruit,30 aromatic plants 25 starch plants,24 nectariferous plants and 18 potherb plants.Most of these plant species are good for exploitation.Furthermore,there are 5 species important national protected wild plants which are belong to 4 families and 5 genera,.Also,there are 17 species age-old and famous trees in Beilun which belong to 15 families and 17 genera.All of these resources are valuable to Beilun which is in the process of exploitation.So it is necessary to protect these resources in order to make them be utilized wisely.
Liuzhou is one of the serious acid rain area in China.The paper adopted contrast research method.The content of several chemical element of Pinus massoniana's tree ring in Changtang and Sanmenjiang in Liuzhou were analyzed and find out the regulation of acid rain and the growth of Pinus massonian's tree ring.The result indicates that acid rain may cause the content of N,P,K ascend and the content of Ca,Mg,Zn,Mn,Al descend in 30 years.Due to the different polluted degree of acid rain in Changtang and Sanmenjiang,,the increased content of N、P、K and the decreased content of Ca、Mg、Zn、Mn were different.
Abstrct Single factor test was used to study the effects of four different types of phosphorus on growth of Prorocentrum donghaiense,NaNO3 was the sole nitrogen source,the initial nitrogen concentration was 40μmol·L-1,and the six original phosphorus concentrations was setup as the following:0.1μmol·L-1、0.5μmol·L-1、1.0μmol·L-1、2.0μmol·L-1、5.0μmol·L-1、10.0μmol·L-1.The four different types of phosphorus were:NaH2PO4(Sodium dihydrogen phosphate),ATP(Adenosine disodium triphosphate),G-6-P(D-glucose-6-phosphate,sodium salt) and G-P(Sodium glyceroophosphate);The results showed that all four types of phosphorus can be utilized by P.donghaiense.When using G-6-P,ATP and NaH2PO4 respectively as the phosphorus source,the maximum Specific growth rate(μmax) and the maximum biomass of P.donghaiense were similar;but when using G-P as the phosphorus source,the maximum Specific growth rate(μmax) and the maximum biomass of P.donghaiense were the lowest.The results further suggest that dissolved organic phosphorus(DOP) in the nature seawater with the similar structure as the former three organic phosphorus can act as the alterative phosphorus source of the outbreak and maintaining of the red tide of Prorocentrum donghaiense.
Huizhou West Lake is a subtropical shallow urban lake in Guangdong Province,southern China.In this study,the lake sediment characteristics were investigated to understand the impact of sediments on water quality.Six sediment cores were taken from five sub-lakes of Huizhou West Lake(Nanhu,Fenghu,Pinghu,Linhu and E-hu) in Aug.2004.The sediments was analyzed for water content,LOI,TN,TP,AAP and grain size.The results showed that the sediments from Nanhu had a several times higher contents of TP,TN,LOI and AAP,and the higher values at lower depths suggested that pollution in this area was very serious.Low variation in the vertical profiles of the sediment from other area indicated the effects of dredging on the sediments.High water turbidity was likely related to small grain size of the sediments and high turbulence caused by fish and boating activity in this lake.
In order to investigate the effect of shrimp-head extract on growth and immune factors of Litopenaeus vannamei,Six added levels of the shrimp-head extract(0,1.0%,1.5%,2.0%,2.5%,3.0%) in the raw diets were fed to the shrimps(initial weight 6.35±0.38 g) for 49 days.The growth performances had no significant differences at all added levels.Compared with the control group,ACP activity in serum of the shrimps increased significantly at 1.5%,2.0%,2.5%and 3.0% added levels;AKP activity in serum of the shrimps increased significantly at 2.0%,2.5%and 3.0% added levels;PO activity in serum of the shrimps increased significantly at all added levels.The results indicated that the shrimp-head extract could strengthen the immunological competence of L.vannamei in suitable supplementation and had potential possibility to be an effective feed additive.
In shrimp culture ponds,a total of 86 species of protozoa were observed,which included 48 species of ciliates,25 species of mastigophorans and 13 species of amoebas.The protozoa communitiy was dominated by species which move slow and feed on bacteria,detrius,and algae,such as Difflugia avellana,Cyclidium citrullus,Vaginicola crystalline,Stentor polymorphrus and Vorticella sp.The protozoa colonized procedure dynamics characteristics indicated that,compared to two control ponds,the protozoan community in sediment-restored ponds resumed growth quicker;The protozoan species number colonized on the PFU was larger,the density was higher;some ciliates which in favor of entrophic water such as Paramecium caudaium,Paruroleptus spp.appeared later.During the cultivation,compared to the control ponds,the protozoan community in experimental ponds was more steady,the protozoan species number and density had lesser variation,pH and water transparency fluctuated littler,and the water quality was better.
Geographic distribution data were collected from field investigation,literature review and museum collections.Environmental variables in the distribution area of small mammals were used for factor analysis to determine the principal factors that affect the distribution pattern of small mammals.The results showed that species richness and precipitation were positively related,whereas the relationship between species richness and average temperature in July,the annual average temperature,and Average annual evapotranspiration were negatively correlative.No significant relationship was observed between the species richness and Average annual evapotranspiration.The factor analysis on the environmental variables which affect the distribution of small mammals revealed that diversity of precipitation,average temperature in July,the annual average temperature,and Average annual evapotranspiration played a dominant role as a basic landscape factor,that total average temperature in January consisted of another principal factor.
The integrated rice and duck farming system,as a comprehensive environmental-friendly planting-breeding technique,is developed from Chinese traditional farming-raising ducks in paddy fields.There exists a mutualism relationship between rice and duck when they grow together in paddy fields.Ducks can take controls on some harmful organisms in the fields.This paper reviewed the effects of rice-duck farming system on rice diseases,pests,weeds and beneficial insects.Based on the study in China,the results showed that the integrated rice-duck farming system can effectively control most weeds,some species of insect pests,and several kinds of diseases of rice.However,it can also take some effects on population of beneficial insects in paddy fields.It also suggested that further studies on the effects and mechanics of raising ducks to control the pests,diseases,weeds and beneficial insects are needed.
Based on the ecological system and sustainable development theory.he indicator system and model for evaluation of ecological community were designed by using principal component analysis method and Remote Sensing/Geographical Information System technology.The evaluating computation was applied in the case study area-within outer ring road of Shanghai City.The results show that:(1) there are disparities of communities within outer ring road of Shanghai City.The score of components spread unevenly within one community or between different communities.(2) In the central area of Puxi,the commonality serving establishments of most communities are perfect,but the housing condition and ecological environment of some communities need further improvements.(3) Although it shows high ecological index and ecological environment quality at some communities in Pudong area,due to the imperfect commonality serving establishments,public traffic system still need to be ameliorated.
In this paper the bio-treatment of sewage containing polyacrylamide(PAM) was studied preliminary.The sewage containing PAM is difficult to be treated,and the increasing sewage quantity in recent years will have a negative impact on the environments.The results of this study indicated that when the 7 PAM degrading bacteria that were separated from the sewage of oilfield cooperated with each other in the optimum medium they can biodegrade the sewage containing PAM effectively.After 3 days the COD of the sewage with additional phosphorus and nitrogen was deceased of 87.7%,after 18 days the COD was deceased from 13499 mg·L-1 to 283 mg·L-1 So the 7 PAM degrading PAM bacteria are very effective in PAM biodegradation and sewage treatment in oilfield.
The diameters、perimeters and areas of normal cell nucleus and cell nucleus infected with Penaeus monodon baculovirus(MBV) in hepatopancreas epithelial cells of Penaeus monodon were studied by micro-imaging analytical technique.The results show that the mean diameter is 3.47±0.30 μm,the mean perimeter is 13.03±1.36 μm and the mean area is 10.87±1.78 μm2 in normal cell nucleus,while the mean diameter is 3.81±0.79 μm,the mean perimeter is 14.00±2.87 μm and the mean area is 13.52±5.37 μm2 in the cell nucleus infected with MBV.There was significant difference between them(P<0.01).Three type occlusion bodies(OB) were measured.The biggest OB is type I and the smallest OB is type III.The most common OB is type I.
A field supervised experiment was conducted to reveal dynamics of cypermethrin in soil and litchi fruit,respectively.The residues of cypermethrin in soil and litchi were determined by gas chromatography.The results of two years' study showed that cypermethrin residues in both soil and litchi fruit disappeared rapidly under field conditions.Its half-lives in soil and litchi were from 8.6 to 9.6 days and from 10.4 to 16.4days,respectively.The final residues of the cypermethrin in soil and litchi at 7th or 10th day after last application ranged from 0.003 to 0.06 mg·kg-1 and 0.0044 to 0.0165 mg·kg-1(litchi pulp) which were less than 0.5 mg·kg-1.
There are three national reserves in Shaoguan,which has the richest nature resource in Guangdong province.Since ecotourism is important for the sustainable development of national reserve,it is necessary to make a quantitative analysis and evaluation of the ecotourism resource for these three national reserves.The traditional evaluation methods are incorporated with fuzzy mathematics to set up evaluation index system.After the comparsionof the nature landscape resource among the three national reserves,which are Chebaling,Nanling,and Danxiashan,an conclusion was drew based on three computing methods.The result shows that the evaluation of resource for Danxiashan is relatively low,Chebaling is better,and Nanling national reserve is the best.Some suggestions of sustainable development,such as constructing ecological networks,enhancing the construction of environment,and the participation of communities,are proposed on the result of evaluation.
In this paper,three Landsat TM images(respectively obtained in1986,1993 and 2003) were interpreted as basic information sources.And the basic data of coastal wetland were obtained with the application of GIS-tech supported by ArcGIS.By calculation and analysis of the landscape pattern index(LPI),the change characteristics of LPI of coastal wetland over the past 17 years were studied.The study shows that there is a decrease in wetland area,from the 419.764 km2 in 1986 to the 394.237 km2 in 2003,with an increase in wetland patcheness,from 810 of 1986 to 1092 of 2003,the landscape fragmentation index of wetland is continuously rising,while the diversity and evenness are decreasing.
The microchemistry of many living matters is often related to reactive oxygen species(RO·).This paper described the sources,species and measurement of RO·.RO· are very strong reactivity groups including 1O2(single oxygen),O2-.(superoxide radical)/HO2·(hydroperoxide radical),·OH(hydroxyl radical),H2O2,RO·(alkylperoxide radical),ROOH(hydroperoxides),etc.ROS could be produced in radiolysis,thermolysis,and redox process.At the present time,their measurements include probe methods,collection of illustrative plates methods,and enzyme methods.
Microsatellite DNA has been shown to be highly polymorphic and co dominant and therefore quite useful as a good genetic marker.However,the wide utilization of microsatellite marker is hindered by the difficulty of obtaining microsatellite loci from interesting species.Recently,many methods have been developed for the isolation of microsatellite loci.Among these methods,database searching is the most convenient method for obtaining new microsatellite loci,such as acquiring primers from published literatures.In recent years,with the increase of EST database,SSRs explored from dbEST have been used in many species.In addition,the conservation of repeat sequence and flanking regions across taxa makes it possible that microsatellite primers from one species can be used to detect polymorphism at homologous sites in related species.The last method is to exploit microsatellite loci from genomic DNA,including the traditional method of genomic library and the novel approach of enriched library such as magnetic bead hybridization and nylon membrane hybridization.
Huizhou West Lake,a famous 4 A scenery in Guangdong province,is a subtropical shallow urban lake.Based on the survey data and the assumption that Huizhou West Lake is a well-mixed lake,a zero-dimension total phosphorus equilibrium model of Huizhou West Lake was established in this paper.The model was used to simulate the concentration of Total Phosphorus in Huizhou West Lake,from Oct.2003 to Sep.2004.The result showed that the model is applicable and feasible in the water quality study of Huizhou West Lake.The error was within the range of allowed.Moreover,an advanced model was developed based on the sediment phosphorus releasing rate.This advanced model can simulate the tendency of total phosphorus concentration of Huizhou West Lake more precisely.
This paper is based on the investigation on soil erosion situation of Nandu River,which the main water supply source in Leizhou.The results indicated that the soil erosion area of Nandu River basin covered mainly the middle and upper stream,that is,the six towns of Yangjia,Baisha,Kelu,Tangjia,Jijia and Songau.The total soil erosion area is 61.23 sq.km.,in which surface erosion is 23.5 sq.km.,ditch erosion is 12.6 sq.km.,landslip erosion is 25.15 sq.km..The soil erosion has been the priority for water resources conservation of Nandu River System.The transformation projects of Nandu River will take effective measures to protect the environment of Nandu River and improve the current situation of soil erosion in Nandu River after investigation and understanding of the current situation of soil erosion in Nandu River.Also,corresponding construction plans for water and soil conservation of Nandu River will be brought up according to its soil erosion situation.
