草-环境系统植物碳氮磷生态化学计量学及其对环境因子的响应研究进展

生态化学计量学(ecological stoichiometry)是研究生物系统能量和化学元素(主要如C、N和P等)平衡的科学,为研究元素在生物地球化学循环和生态过程中的计量关系和规律提供了一种综合方法。陆地生态系统方面的研究虽然起步较晚,但近10年来也取得了较大的发展,已涉及到天然草原、森林、湿地和农田等亚系统,研究内容除了测定生态化学计量比,还将不同系统、功能群和物种间植物的计量学特征进行比较,以及将计量学特征与环境因子偶联研究。笔者对草-环境系统植物C、N和P生态化学计量学的研究进行了综合分析,重点论述了天然草原系统植物C、N和P生态化学计量学特征及其对环境因子的响应规律。

Temporal population dynamics of dinoflagellate Prorocentrum minimum in a semi-enclosed mariculture pond and its relationship to environmental factors and protozoan grazers

The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to August,followed by a sharp increase from the middle of August,reaching a single maximum peak value of 2.2×105 cells L-1 in October.Temporal variation in abundance was positively correlated with dissolved nitrogen,but showed a significant inverse relationship to abundance of the dominant ciliates,Tintinnopsis lohmanni and Askenasia stellaris.The results provide statistical evidence that the number of P.minimum increased with increasing nitrogen,and the suppression or shortening of algal bloom may be associated with protozoan grazers,such as Tintinnopsis lohmanni,in mariculture ponds.

Vegetation-environment Relationships Between Northern Slope of Karlik Mountain and Naomaohu Basin,East Tianshan Mountains

Based on data from 22 sample plots and applying the Canonical Correspondence Analysis （CCA）, this paper discusses the vegetation-environment relationships between the northern slope of Karlik Mountain and Naomaohu Ba- sin, which is situated in the easternmost end of the Tianshan Mountains, Xinjiang Uygur Autonomous Region, China. For the zonal vegetation, community diversity of mountain vegetation is higher than that of the desert vegetation due to environmental factors. The CCA ordination diagram revealed that the composition and distribution of vegetation types are mainly determined by altitude, soil pH and soil salt content. With increasing elevation, the soil pH and total salt content decrease but the contents of soil organic matter, soil water, total nitrogen and total phosphorus increase gradu- ally. In the CCA ordination diagrams, the sample plots and main species can be divided into five types according to their adaptations to the environmental factors. Type Ⅰ is composed of desert vegetation distributed on the low moun- tains, hills, plains and deserts below an elevation of 1900 m; type Ⅱ is distributed in the mountain and desert ecotone with an elevation of 1900-2300 m, and includes steppe desert, desert steppe and wetland meadow; type Ⅲ is very sim- ply composed of only salinized meadow; type Ⅳ is distributed above an elevation of 2300 m, containing mountain steppe, meadow steppe, subalpine meadow and alpine meadow; type Ⅴ only contains salinized meadow. The results show that with increasing elevation, species combination changes from the xerophytic shrubs, semi-shrubs and herbs distributed in the low altitude zone with arid climate to the cold-tolerant perennial herbs growing in the high altitudinal zone with cold climate.

Evaluation on Coordination between Grassland Ecological Environment and Economic Development

Taking grassland resources in Nagqu District of Tibet as example,the evaluation index system of environment and economy coordination degree was set up according to coordination degree evaluation model,and environment economic system coordination degree of 11 counties in Nagqu District was analyzed by using coordination functions.

Biomass Allocation of Scirpus mariqueter Along an Elevational Gradient in a Salt Marsh of the Yangtse River Estuary

Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stress, the biomass allocations to different plant components and some related morphological parameters were examined along an elevational gradient within a salt marsh. Authors found that S. mariqueter performed best at medium elevation within the marsh, with relatively high density of shoot and individual ramet dry mass. Biomass allocation to corm was the highest at low elevations, and the least at high elevations, suggesting that a conservative strategy was adopted by the species to cope with the harsh physical conditions at the low elevation. The investment in rhizome decreased from low to high elevations, while the proportion of inflorescence mass increased, indicating that during the life history, the species shifts from predominant asexual reproduction to predominant sexual reproduction. This may be favourable for the species to colonize larger area, and to spread and persist at a meta_population level. Correlation analyses showed that sexual reproduction was inversely related to growth and asexual reproduction. However, it is difficult to determine the relationship between asexual reproduction and growth possibly because of the varied function of the corms of the species in different life history stages.

Comprehensive Quality Assessment of Groundwater Environment in Typical Arid Grassland

[Objective] To comprehensively assess the groundwater quality in typical arid grassland. [Method] Based on the survey of pollution sources and analysis of onsite water quality monitoring of Darhan Muminggan United Banner （Damao County） which situated in the inland river basin at the north foot of Yinshan Mountain, the Nemero index method was used to assess the groundwater quality of this area, and the causes for the pollution were also analyzed. [Result] The groundwater quality in Damao County is between poor and very poor. [Conclusion] This study laid the foun- dation for the control of groundwater pollution in Damao County.

Tolerance of Grasses to Heavy Metals and Microbial Functional Diversity in Soils Contaminated with Copper Mine Tailings

Copper （Cu） mine tailings, because of their high content of heavy metals, are usually hostile to plant colonization. A pot experiment was conducted to determine the tolerance of four forage grasses to heavy metals in Cu mine tailings and to examine the variation in the microbial functional diversity of soils from the tailing sites in southern China. All the four grass species survived on Cu mine tailings and Cu mine tailing-soil mixture. However, on pure mine tailings, the growth was minimal, whereas the growth was maximum for the control without mine tailings. The tolerance of grasses to heavy metals followed the sequence： Paspalum notatum 〉 Festuea arundinaeea 〉 Lolium perenne 〉 Cynodon daetylon. The planting of forage grasses enhanced the soil microbial biomass. The Biolog data indicated that the soil microbial metabolic profile values （average well color development, community richness, and Shannon index） of the four forage grasses also followed the sequence： P. notatum 〉 F. arundinaeea 〉 L. perenne 〉 C. daetylon. Thus, P. notatum, under the experimental conditions of this study, may be considered as the preferred plant species for revegetation of Cu mine tailing areas.

Seed Bank of Amorpha fruticosa L. on Some Ruderal Sites in Serbia

Amorpha fruticosa L. （Fabaceae）, known as indigo bush, false indigo bush, false indigo and desert false indigo, is deciduous shrub （1-6 m tall）. The woody weed species A. fruticosa has a high environmental adaptability and is present in different environmental conditions. In Vojvodina region （Northern Serbia）, it is mostly present near irrigation channels and river banks, especially in alluvial or marshy areas. Since A. fruticosa is continually spreading near river banks, the aim of research was to determine seed bank composition near the Danube River. in 2014, soil sampling was performed at localities with high population of A. fruticosa （3-4 plants at age over two years and 10-14 plants at age 1-2 years）. Soil samples were taken from two localities （Futog and Sangaj） with alluvial sandy soil and chernozem near the Danube River. Each sample was sieved through a system of copper sieves of various diameters. After the separation of seeds from samples, they were identified. Significant presence of A. fruticosa seeds （1,914 seeds/m2） was established in a layer of 0-10 cm. In the same soil layer, the significant presence of seeds of Stellaria media （L.） Vill. and Urtica dioica L. were also established. Seeds ofA. fruticosa were not found in soil layers 10-20 cm and 20-30 cm. The invasive weed species A. fruticosa produces a large number of seeds in two cycles. The majority of the seeds stay in the upper soil layer, being dispersed by water （hydrochory）.

Influence of litter layer on ecological environment in northeastern leymus chinensis grassland of China

In this paper, we adopted simulation method to discuss influences of litter layer on plants habitat in grassland. Results indicated that ground surface evaporation, soil moisture, surface temperature, soil pH, soil bulk density and soil porosity were all strongly related to the litter quantity. Potassium （K） and organic materials in the soil covered by litter layer were higher than those in the soil uncovered by litter layer. With 100 g.ln-z increase of litter, the percentage of organic materials increased by 17.9%, nitrogen （N） increased by 7.6%, phosphor （P） increased by 26.4%, and K increased by 3.8%. With the litter accumulation amounting up to 600 g-m-2, the percentage of organic materials increased by 1.8 times, N increased by 81.5%, P increased by 1.8 times and K increased by 26.4%. According to the expected coefficient method of optimization, a mathematical model was established about the optimal accumulation quantity of litter.

Land Use/Cover Changes and Environmental Consequences in Songnen Plain,Northeast China

The Songnen Plain in Northeast China,one of the key national bases of agricultural production,went through remarkable land use/cover changes in recent years.This study aimed to explore the long-term land use/cover changes and the effects of these changes on the environment.The Landsat-based analysis showed that,during 1986-2000,cropland,built-up land and barren land had increased,among which cropland had the largest increase of 9,198km2 with an increase rate of 7.5%.Woodland,grassland,water body and swampland had decreased correspondingly,among which grassland had the most dramatic decrease of 6,127km2 with a decrease rate of 25.6%.The transition matrix results revealed that grassland,woodland and swampland were the three main land use types converted to cropland.Climate warming created the potential environment for the conversion of grassland and swampland into cropland.Land resources policy made by central and provincial governments of China affected the pattern and intensity of land use.Land use/cover changes accompanied by climatic variation brought out a series of environmental consequences,such as sand desertification of land,land salinization and alkalinization,grassland degradation,and more frequent floods.Under this circumstance,optimized land use structure and restoration measures are needed.

Efficiency and mechanism of degradation of alachlor in water by O_3/H_2O_2 catalyst system

Alachlor is used widely as a herbicide,but is an environmental endocrine disruptor. O 3/H 2O 2 system is used as catalyst to delve on the degradation efficiency of alachlor. The amount of the catalyst H 2O 2,the pH value of the soluble, the temperature and quality of water sample are changed to investigate the effect of these factors on the degradation of alachlor. The degradation of alachlor is qualitatively analyzed through their GS MS spectra and the possible mechanism of the degradation of alachlor is discussed as well.

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

Among fertilizer ingredients nitrogen is the one noted for biggest losses because its susceptibility to volatilize to the atmosphere and to be leached away from the soil. These losses depend on the level and mode of fertilization. It appears that every year in Poland river waters transport to the Baltic Sea from the whole area about 180 thousand tons of the nutrient. The largest portion of this load is ascribed to agriculture. This study focused on the highland areas, which are commonly seen as a water supplying region owing to the fact that they cover about 35% of water need in the authors＇ country. Specificity of grassland fertilization in these lands is high contribution of natural fertilizers including dunging with fresh manure left by penned animals, particularly by sheep. Authors decided to assess the influence of dunging by folded sheep on meadow nitrogen balance and on its concentration in percolating water. It was demonstrated that a nitrogen balance was highly negative for each object, so the grassland plants supplied their needs in large part with nitrogen from mineralization of soil organic matter. Relatively high loads of nitrogen leached out of the folded objects indicate that nitrogen from mineral fertilizers is better utilized by grassland herbage and thus is much safer for soil and water environment.

Review on Chlorobenzoic Acids Biodegradation and Their Environmental Impacts

Chlorobenzoic Acids are toxic organic compounds largely distributed in soils and sediments. They can be degraded to various products by microorgans. This paper is a review of the literature on biodegradability of the chlorobenzoic acids. The degradation pathways, degradation genes, role of transposable elements, and construction of strains are discussed. A brief introduction is given on the environmental impacts and the pollution control.

Climate Characters of Summer Drought in Mountain City and the Effect on Flowers and Trees

[Objective] The aim was to provide references for development of industries engaging in flowers and trees in Beipei area in Chongqing. [Method] The occurring trend, intensity trend of summer drought, relationship of intensity with rainfall and extremely highest temperature, occurring trend during initial period of summer drought and the effects in mountain cities were analyzed, based on information on lasting period, rainfall, average temperature, extremely highest temperature of sum- mer drought in Beipei area in mountain cities during 1981-2010 and, growth condi- tion and phenological phenomena of Michelia champaca during 2005-2007. [Result] The occurring probability of summer drought in mountain cities was 57% and the probabilities of light, moderate, heavy and extreme drought were 30%, 10%, 7% and 10%; intensity of summer drought was none of linear relation with rainfall and ex- tremely highest temperature. In summer drought, daily average rainfall was less than 0.9 ram; extremely highest temperature was 35.0-45.0 ℃ with probability at 30%; initial period of summer drought was from later June to middle August and of extreme drought was later June-later July; the ending period was early September. During drought, when the extremely highest temperature （〉35.0 ℃） occurred in three days within a Hou, flowers and trees were affected by the hot drought and when the extreme temperature （〉40.0 ℃） occurred in three days within a Hou, the plants were seriously affected. [Conclusion] Based on characters of summer drought, pre- cautions can be taken to reduce effects of summer drought on flowers and trees with the help of weather forecast.

Higher Education on Building Energy and Sustainability in North Dakota

Located in the cold and very cold semiarid steppe climate zone, North Dakota boasts not only long cold winters but also hot summers, which significantly increases the energy consumption of buildings. In fact, North Dakota has the highest energy consumption per capita in residential buildings （101 MM Btu in 2013）, and its energy consumption per capita in commercial buildings ranks the second （l 18 MM Btu in 2013） in the nation. When humans spend a long time indoors to escape the inclement weather, their health will be more susceptible to the indoor environment. In addition, North Dakota has the 3rd least number of green buildings certified by LEED （Leadership in Energy and Environmental Design） in the nation. This paper aims to investigate the status quo of buildings with respect to energy, health and sustainability in North Dakota, and attempts to propose strategies regarding research and higher education to rectify the current issues. These strategies include but not limited to forming the architectural engineering program, a comprehensive and interdisciplinary program in buildings.

Aquatic Toxicities of Three Aryloxyphenoxypropanoic Acid Herbicides on Cyanobacterium Microcystis aeruginosa

Pesticides will be released into aquatic systems after application in agriculture or industry. AOPPs （aryloxyphenoxypropanoic acids） herbicides, including fenoxaprop, quizalofop-P-ethyl and haloxyfop-methyl, can pose aquatic toxicity on cyanobacterium M. aeruginosa （Microcystis aeruginosa）. The inhibition percentages of the biomass of M. aeruginosa exposure to 10 mg＇L-I fenoxaprop, quizalofop-P-ethyl and haloxyfop-methyl on day 7 were 23.13%, 7.55%, and 7.56%, respectively. Protein content was also inhibited by the three AOPPs to fenoxaprop is the most toxic, followed by quizalofop-P-ethyl varying degrees. The growth and protein content results showed that and haloxyfop-methyl. It indicates that both the biomass and the protein content can be served as an indicator for evaluating the toxicity of the three chemicals. Growth rates of M. aeruginosa exposure to fenoxaprop are also the most significantly different compared to the control, which means that fenoxaprop is the most toxic among the three compounds. Results from this study may provide insights for evaluation of environmental risks of AOPPs. In addition, such insights will be helpful for guiding the application of AOPPs in agriculture.

Technical, Economic and Environmental Evaluation on Mechanical Rice Straw Gathering Method

Rice straw is a rice by-product, which is currently mostly wasted in Vietnam, in particular in the Mekong delta. At present, the cost of straw gathering is increasing because of the increased use of combine harvesters. High labor cost and lack of labor makes manual collection unfeasible. Farmers therefore often just burn it, which causes pollution, increased greenhouse gas emissions and loss of opportunities to value add. An economic and environmental evaluation and technical field testing of a straw baler with 4 ha/day capacity was therefore conducted in Long An province. During the field testing data on the gathering capacity, fuel consumption, labor requirement and other cost items were collected. The test results showed that the baling cost is US$19.0 per ton of rice straw, the pay-back period of 2. 1 years and the internal rate of return of 38%. In addition to the baling cost, the transportation cost varies from US$24 for a distance of 100 km to US$32 for 150 km. The benefits of the machine are not only economical but also include the reduction of field burning.

The status and protection of the ecological environment in Heihe River water source district

This article discusses the status of the ecological environment in Heihe River water source district, and points out that the decline of the forest coverage, the degradation of the pasture and the shrinking back of the glacier, the increased soil erosion and other phenomena are the main ecological and environmental problems in this area. The main reason is the natural and man-made results. This article proposes the specific measures to protect the ecological environment in Heihe River water source district.

Vegetation Pattern in Northern Tibet in Relation to Environmental and Geo-spatial Factors

Environmental and Geo-spatial factors have long been considered as crucial determinants of species composition and distributions. However,quantifying the relative contributions of these factors for the alpine ecosystems is lacking. The Tibetan Plateau has a unique ecological environment and vegetation types. Our objectives are to quantify the spatial distributions of plant communities on the Northern Tibetan Alpine grasslands and to explore the relationships between vegetation composition,Geo-spatial factors and environmental factors. We established 63 field plots along a 1200-km gradient on the Northern Tibetan Plateau Alpine Grassland and employed the two-way indicator species analysis（TWINSPAN） and the detrended canonical correspondence analysis（DCCA）. Fourteen communities of alpine grassland were identifiable along the transect and consisted of three vegetation types： Alpine meadow,Alpine steppe,and desert steppe. Vegetation composition and spatial distribution appeared to be largely determined by mean annual precipitation and less influenced by temperature. A large fraction（73.5%） of the variation in vegetation distribution was explained by environmental variables along this transect,somewhat less by Geo-spatial factors（56.3%）. The environmental and Geo-spatial factors explained 29.6% and 12.3% of the total variation,respectively,while their interaction explained 43.9%. Our findings provide strong empirical evidence for explaining biological and environmental synergetic relationships in Northern Tibet.

Environment-ecosystem dynamic processes of Spartina alterniflora salt-marshes along the eastern China coastlines

Spartina alterniflora is ecologically important in its original habitat; however, it has caused controversy since it was introduction into China(now it has been spreading rapidly on the Jiangsu, Shanghai, Zhejiang and Fujian coasts). The purpose of the present contribution is, on the basis of an analysis and synthesis of existing data sets, to evaluate the environmental-ecological effects of S. alterniflora, and to identify the relevant scientific problems that require further research in the future. Investigations have shown that, by reducing the near-bed shear stress associated with tidal currents, S. alterniflora can enhance the settling flux of suspended sediment and deposition rate on the tidal flats over the region. Further, field survey and analysis indicate that the S. alterniflora salt-marsh has a high primary production and provides a new type of habitat for the native benthic fauna. Some macro-, meio- and micro-fauna that used to live in the native salt-marshes have adapted to the S. alterniflora salt-marsh, forming a new ecosystem. Under the influences of a number of background factors, such as latitude variations and the coastal type, the environmental-ecological changes induced by Spartine have regional differentiations. To the north of Hangzhou Bay, with a high position of the pre-Holocene stratum base, a large width of the tidal flats, and a gentle bed slope, only a small part of the intertidal zone is occupied by the S. alterniflora salt-marsh. Here, the S. alterniflora salt-marshes mainly play a positive role in coastal protection and ecosystem functioning. In contrary, to the South of Hangzhou Bay, The pre-Holocene deposits are situated in relatively deeo waters, and the width of the tidal flats formed within coastal embayments is relatively narrow. As such, the expansion of S. alterniflora has squeezed the living space of other intertidal organisms, thus has a negative ecological effect. Therefore, the regional differentiation of the Spartina effects should be sufficiently considered in coastal development and management. Furthermore, in order to predict the future evolution of the S. alterniflora wetlands over the region, in addition to in situ monitoring and measurements, an ecosystem dynamic model should be established, taking into account the coupling of the rerrestrial and marine environmental-ecological processes.