Grasslands can be the important Riparian buffer strips to play a significant role in ameliorating rivers' water quality and ecological functions. Selecting Festuca arundinacea,Trifolium repens and Cynodon Dactylon L.Pers as experimental plants,This study tested the soil physical and chemical indices,plant root-system indices as well as soil fauna indices in each sample plot to analyze the impacts by different grasslands on such ecological functions of riparian buffer strips for water and soil conservation and biodiversity maintenance. Results showed that the grassland of three types could all improve the soil quality and biodiversity maintenance compared to the vegetable field and wasteland nearby. Festuca arundinacea excelled in soil conservation and,Trifolium repens had advantages in diversity maintenance of soil fauna,while Cynodon Dactylon L.Pers had obvious abilities to adjust soil's physical and chemical quality.
Changes in the activity of antioxidant enzymes including peroxidases (POD) and superoxide dismutases (SOD) and in the contents of chlorophyll (CHL),malondialdehyde (MDA),and soluble proteins (SP) in wheat (Triticum aestivum L) under the stress of Pb in soil were examined. The results showed a decrease of chlorophyll content in the leaves,and the concentrations of MDA and SOD level were not significantly increased. The POD activity could be induced to increase under the stress of Pb. The inhibition of protein biosynthesis by Pb was one of the toxic mechanisms involved. The activity of POD and SOD,contents of MDA and CHL could not be considered as biomarkers of stress by Pb in soil. While the contents of SP could be considered as biomarkers of stress by Pb in soil.
The formation and evolution of vegetation sowed by airplane in the Alxa Desert is closely related to the amount and distribution of rainfall in growing season. The results in this study showed that the percentages of callogonum mongolicu,Psammochloa mogolica and Artemisia sphaerocephala in this area were higher than other species when the monthly rainfall is more than 65 mm during planting period. Furthermore,the important values were 64.5%、61.59% and 23.67% respectively and the biomass was 2038.20 kg/hm2. The percentages of Artemisia aphaeocephala and Peganum nigellastrum in this area were higher than other species when the monthly rainfall is less than 40mm during planting period. Their important value were 65.51% to 66.58% and 35.71% to 46.11% respectively and the biomass was 1827.30 to 1834.65 kg/hm2. In additionally,species richness also varied with different seasons in this area. The important value and the biomass of A. sphaerocephala increased,but the percentages of A. sphaerocephala were stable,which indiacted that A. sphaerocephala were adaptable during growing season,from June to September. For Calligonum mongolicum,the important value and biomass increased from June to August,but decreased in September. However,it is relatively stable among all species. The biomass and the important value of P. mogolica decreased with seasons,which indicated the degradation of P. mogolica. Above results showed that planting Artemisia sphaerocephala and calligonum mogolica is an effective measure for controlling degradation in the Alxa Desert.
The Isochrysis zhangjiangensis were treated with 7 different of organic compounds,which were glucose,sodium acetate,galactose,glycerin,ethanol,sodium citrate and glycin. The results showed that growth of algae cells was significantly improved by glycin,but not by ethanol. Others organic compounds also could improve cell growth different extent. Different organic compounds had different effects on accumulations of proteins and fatty acids in the cells. The accumulations of proteins and fatty acids were improved when algae cells were treated with 0～10g·L-1concentrations of glucose or sodium acetate,but not improved when treated by glycerin or galactose. Only in a certain concentration range could ethanol,sodium citrate or glycin improve the cell accumulations of proteins and fatty acids.
In this paper,effect of acetanilide herbicides butachlor on Phsiological and Biochemical Characteristics of Microalgae Dunaliella salina was studied in the laboratory. The results showed that the growth of Dunaliella salina was stimulated under low concentration of butachlor culture medium and significantly inhibited under high concentration of butachlor culture medium. Butachor also had effects on the activities of photosynthetic pigment,protein content,superoxide dismutase (SOD) and peroxidase (POD) of Dunaliella salina.
In this study,sulfur content of the leaves and chlorophyll fluorescence of 9 garden plant species from Shenzhen were measured in November 2005 to evaluate effect of atmospheric SO2 in order to select bio-indicators for atmospheric SO2 monitoring. These plant species include Excoccaria cochinchinensis,Sanchezia nobilis,Codiaeum variegatum,Saruma henryi,aryota mitis,Ficus microcarpa var.pusillifolia,Ficus altissima,Pittosporum tobira and Duranta repens cv.\'Dwarf Yellow\'. Leaves from the 9 plant species were treated with distilled water and NaHSO3,their sulfur contents and chlorophyll fluorescence were measured under light or dark conditions at temperature of 25℃. In the natural condition,the sulfur content in leaves of Sanchezia nobilis was the highest,and that for Codiaeum variegatum was the lowest. The sulfur contents of leaves treated with distilled water from the 9 species showed small change. When treated with NaHSO3,the sulfur contents in sevenof the 9species increased,especially in the leaves of C.variegatum. The same 9 species were collected from two gardens where the atmospheric SO2 concentration is different: Small Nan Hills with high air SO2 and World Exhibition Park with low air SO2. Except for P.tobira,the other 8 species had higher sulfur contents and lower Fv/Fm in Small Nan Hills than in the World exhibition Park. This result demonstrates that Fv/Fm of the 9 plant species is a suitable parameter to indicate pollution from atmospheric SO2.
The litter breakdown in lake and wetland is poor known in tropical and subtropical regions. To investigate the decomposition of leaf litter in lentic environment of subtropical region,breakdown rates of ear-leaved acacia (Acacia auriculaeformis) and sapodilla (Manilkara zapoto) leaves were measured over a 130-day period using coarse-mesh bags in an oligotrophic pond at the Changgangshan Nature Reserve,Guangzhou. The results showed that the decomposition rates of these two leaf species were quite slow. After 130 days,ear-leaved acacia leaves and sapodilla leaves lost 25.7% and 22.5% of their initial mass only. The daily breakdown coefficients (k) of A. auriculaeformis and M. zapoto were respectively 0.00145 d-1 and 0.00105 d-1 which fitted well by an exponential decay model. The macroinvertebrates colonized on two leaf species were only five species,of which Chironomus sp. and Gammarus sp. were dominant benthos. The results suggest that the scarcity of shredders is one of main factors which make the breakdown rates of these two species much slower.
Landscape pattern is a main content of landscape ecology which plays an important role in biodiversity conservation. In this paper,the landscape diversity,mean patch fractal dimension and landscape evenness were calculated to analyze the spatial structure and dynamic character of landscape pattern in Qingxiushan mountain area in Nanning city. The result indicated that human activities were the determining factors of landscape pattern. Through comparing natural features and features of human activity with the landscape indices,we found that the determining factors in different of landscape districts are not the same. Landscape diversity and evenness of Qingxiushan Mountain increased with time. The phenomenon which one of the landscape type occupied a dominant position has not been found. Except the Conifer and Broadleaf mixture forest,the number of patch of each landscape increased with time. The shape of patch was more complex in 1985,since then,it became more regular with time. So the forest in Qingxiushan mountain was disturbed intensively by human activities.
Planktonic algae of some small eutrophic and adlittoral artificial Lake in the city zone of Guangzhou and their water quality were studied in July 2005 to February 2006. Fifty-four species in seven phylums of planktonic algae was indentified,which mainly consisted of Chlorophyceae,Cyanobacteria,acillariophyta and Euglenophyta.The dominant species was Chlorococcale,which consisted 26 phylums,62 species,and 45.6 percent of total algae species. Overall,the mean total cell number in the lake was high. In February 2005,it reached to 10.8×106 cell·mL-1; Base on the Kolkwitz water quality system,the species of planktonic algae which belong to α、β-middle pollution zone are the most. And water quality is evaluated by Margalef index standard and TSI which bases on amended Carlsoon Index. The result indicated that the water was eutrophic with Mid-High Pollution. The level of water be polluted which changed with season was evident: Winter>Autumn>Summer.
With the help of GIS,and based on RS image MSS of 1979,TM of 1990 and ETM of 2000,and by using the indices of the landscape pattern,this paper studied the landscape change from 1979 to 2000 in Huadu Section of Guangzhou city. The results show that: (1) In Huadu Section,there were rapid increases in the patch number and area variety. (2) The residential area and construction area in this section increased. (3) The woodland and farmland were mainly transformed to construction area and residential area. (4) The landscape change was accelerating in the study area.
Phosphorus release character from the sediment of Dajingshan Reservoir during the transition from anoxic to aerobic condition was studied by simulation experiments. Phosphorus was released from the two types of sediments collected from the dam area and the centre of the Dajinshan reservoir during the period of the study. Phosphorus release rate at the dam area is faster than that of the centre of the reservoir. Release rates for both the total phosphorus and the total dissolved phosphorus increased at first and then decreased slowly then get to the peak two weeks later. Release rate of the dam area for both total phosphorus and total dissolved phosphorus reached the maximum of 6.64 mg·m-2·d-1 and 1.37 mg·m-2·d-1,respectively. And for the sediment from the center of the reservoir were 3.24 mg·m-2·d-1 and 0.62 mg·m-2·d-1,respectively. The redox potential and pH for the overlying water in the simulation experiments showed a decreasing trend,which are two important factors affecting phosphorus release rate.
Our survey was conducted between Mar. 2004 to Mar. 2005 in the area the area of 22°33′to 22°41′N,113°37′to 113°42′E. The results showed that densities of Skeletonema costatum were higher at the outer estuary than those at the inner estuary and one high density peak was observed in the typical annual monitoring. The relationship between densities of Skeletonema costatum and its environmental factors was studied by correlation analysis. There was a notably negative correlation between the densities of Skeletonema costatum and phosphate,and was a notably positive correlation between the densities of Skeletonema costatum and silicate; no obvious relation was not found for environmental factors. Phosphate and silicate are likely to be the limit factors for Skeletonema costatum in Guangzhou sea area.
The toxic effects of Butylated hydroxyanisole (BHA) and Norfloxacin (NFLX) to Scenedesmus obliquus and Daphnia magna was studied through acute toxicity test index. The results showed that BHA and NFLX remarkably restrained the mobilization of D. magna,even causing them death in the given concentration. LC50 value of BHA and NFLX for D. magna at 48h were 3.15mg L-1 and 194.98mg L-1,respectively. BHA and NFLX also had the toxicity effect on S. obliquus and 96h EC50 value were 6.19mg L-1 and 50.18mg L-1,respectively. Based on the EC50 and LC50 values,BHA and NFLX belonged to mid-toxic and low-toxic to Aquatic Organisms. Compared with D. magna,S. obliquus showed more sensitive to NFLX. While D. magna showed more sensitive than S.obliquu to BHA.
The effects of humidity and temperature on the survival period of time and energy-consuming of juvenile Bufo melanostictus Schneider was investigated with 9 different humidity and temperature conditions. Results showed that the optimal humidity and temperature for their surviving is 24℃ in shallow water in which they can survive as long as 22 days while 32℃ high temperature with dry ambient is not suitable for their surviving. The results of their physical energy-consuming changes in different humidity and temperature also showed that the key factor that affects their survival time is not the food shortage but humidity and temperature.
In this paper,the habitat dynamics characteristics of red deer Tarim subspecies were analyzed by using geographical information system (GIS) to assess the factors that mainly impact the red deer habitats in populus natural reservation area in Xinjiang,China based on the spot investigation and historical data from 1973 to 2003. The results showed that from 1973 to 2003,in the natural reservation area the habitat types suitable for the red deer Tarim subspecies distribution have decreased. Among them (1) Water resource and area were diminishing heavily,though state has strengthened management of water resource,the effect is not so obvious. (2) The surface of the desertification area and the vegetation of low coverage have been decreased slowly,but the vegetation has highly coverage have been decreased rapidly,at the same time the surface of the cultivated lands have been rapidly increased,desertification is in process. The mainly reason make change the habitat pattern are different human activities.
The birds at airports are threatening the flight safety for their special living place. Different birds have different risk values because of their features. the objective for this paper is to identify a simple and useful method to evaluate the risk of birds based on some useful mathematic methods. A case study shows how to calculate the risk. The results showed: among the 70 species of the birds we observed in the research region,species of highest risk is 24.29%,of high risk,30.00%,of average risk,30.00% and of lowest risk,15.71%. The first two kinds are those species needing meliorating at first. The risks of every bird risk index are also calculated. The results can be used as a quantitative basis in evaluation birds and resolving the bird strikes at airports.
In order to understand the distribution of microorganisms in fluidized-pellet-bed (FPB) bioreactor,bacteria enumeration in different heights (10cm,60cm and 110cm) of FPB was conducted respectively regarding total heterotrophic bacteria,denitrifying bacteria and sulfate-reducing bacteria. Microscopic,scanning electron microscopic (SEM),microbe fixation and embedding techniques were also applied. It was found that aerobic bacteria were dominant in both the bulk solution and pellets along the bed height,and the aerobic bacteria was about 1.6×108 CFU·g-1 sludge at 10cm height,It can be concluded that aerobic bacteria are playing the leading role of biological degradation in the FPB bioreactor. However,certain amount of anaerobic bacteria were found in the bioreactor and there was a tendency of increase of anaerobic bacteria in the upward direction,It was related to the rapid decreasing of dissolved oxygen (DO) along the bed height. As DO supply was enhanced by increasing the recycling flow ratio,the amount of the aerobic bacteria apparently increased while the amount of the anaerobic bacteria decreased. With single pellet particles,differences were noticed between the outer surface layer and inner cores in number of microbes.
Ecological Sensitive Factors (ESF) and Ecological Sensitive Area (ESA) are significant to regional ecology. They are the important bases in regional planning and mass cities planning. This paper divides Ecological Sensitive Area into five types,from the vision of atmosphere,water,propagation,land,geology,and constructs an indicator system for Ecological Sensitive Area Division. Case study in Beibu Gulf (Guangxi) Economic Zone shows the division method used in mass cities area,which provides a standard method for Ecological Sensitive Area Division. The result of the case study analyzes some ecology problems in this area and provides ecology reference for later mass cities planning.
Trophic dynamic aspect of ecology by Raymond Lindeman provided a novel conceptual model for studying energy flow in aquatic ecosystems. Lindeman's Ecology manuscript is now considered foundational work in the histories of ecology and limnology and seminal work in ecosystem ecology. This work was one of the first papers to implement Arthur Tansley's newly proposed ecosystem concept in a quantitative manner and was groundbreaking in several ways. The work's most enduring contribution is that it provided a common currency (organic matter or energy flow) for studying interactions among trophic levels and for comparing disparate aquatic ecosystems,thus establishing a theoretical orientation in ecology. Today,Lindeman's model is still instrumental in ecological research.
Dissolved organic matter (DOM) is an important component in soil solution,it have vital function on soil chemical and biological process. Although DOM is just a little portion in the natural organic material,it connects mineral with organic material and controls the transference,transform and end-result of environmental pollutants. As a result,scholars round the world pay a lot of attention to the influence of organic material on soil pollutant's environmental action. This paper gives a review about the classify and separate technology of dissolved organic matter (DOM),with the information on the structure and the taken method of DOM,the surface reactivity of DOM and it's effect on the adsorption and transference of organic contamination and heavy metal in the soil. And some aspects for further research are also proposed.
Eco-tourism in Nature reserve can not only improve the public environment awareness and increase the reserve income but also impact on the eco-equilibrium and the fauna and flora resources. How to treat the relationship between the natural conservation and the eco-tourism has already attracted ever-greater concern from more and more people. The authors have surveyed and analyzed the eco-tourism in both national and international nature reserves. The conclusion is that when the reserve carries out eco-tourism the effective management,the measurement should be taken with a scientific plan. A perfect management and monitoring system should be taken as well in order to prevent the nature resources and the eco-environment.
