基于流式细胞特性的LNA和HNA细菌相关性研究

采用流式细胞技术分析了7种不同陆地环境介质中LNA和HNA细菌的浓度变化及流式细胞特性特征.结果显示,在水体和土壤等环境中都存在LNA和HNA细菌的分类,其中,土壤环境中LNA细菌浓度(10⁷~10⁸cells/g数量级)高于水环境中浓度(10⁵~10⁶cells/mL数量级),但其相对比重(29.80%~33.94%)低于水环境(除地下水外,21.60%)中LNA细菌(42.25%~65.92%),主成分分析(PCA)显示水体和土壤环境介质中LNA和HNA流式细胞参数具有明显差异;相关分析表明,LNA与HNA细菌的流式细胞参数(绿色荧光信号FL1和侧向散色信号SSC)之间具有显著相关性(FL1:R²=0.711, P<0.01, SSC:R²=0.762, P<0.01),在不同生态系统中SSC变异大于FL1变异.结果表明,LNA和HNA细菌之间既不是各自对应的某一特殊生理阶段细菌,也不是两个完全相互独立的细菌群体,而是具有特殊共变关系的细菌.     

ANADROMOUS SALMONID RECOVERY IN THE UMATILLA RWER BASIN,OREGON: A CASE STUDY1

ABSTRACT: The Umatilla River Basin Fisheries Restoration Plan was initiated in the early 1980s to mitigate salmonid losses caused by hydroelectric development and habitat degradation. The objectives are to enhance the abundance of endemic steelhead and reintroduce extirpated chinook and coho salmon. The project prompted collaborative effort among federal, state, and tribal agencies, and local water users. It has incorporated habitat restoration, flow enhancement, fish passage improvements, and population supplementation through artificial production. Water exchanges have successfully increased minimum flows during spring and fall migration. While flows remain depressed compared to historic conditions, there is potential for improved habitat, passage, and homing. The mean adult‐to‐adult return rate of hatchery‐reared steelhead exceeded replacement and that of the naturally‐spawning population. Although the smolt‐to‐adult survival rates of hatchery‐reared fish fluctuate, salmonid escapement has increased in recent years, permitting steelhead and spring chinook harvest. Enumeration of potential spawners and observed redds reveals an increase in natural production of all supplemented species. Comparison of hatchery‐reared and naturally‐spawning steelhead populations revealed differences in life history characteristics (in age composition and sex ratios) though run timing and genetic stock compositions of the two components of the populations have not differed. Sustained monitoring is needed to determine benefits of integrating habitat restoration and artificial production in restoring salmonid populations.     

GRASS VERSUS TREES: MANAGING RIPARIAN AREAS TO BENEFIT STREAMS OF CENTRAL NORTH AMERICA1

ABSTRACT: Forestation of riparian areas has long been promoted to restore stream ecosystems degraded by agriculture in central North America. Although trees and shrubs in the riparian zone can provide many benefits to streams, grassy or herbaceous riparian vegetation can also provide benefits and may be more appropriate in some situations. Here we review some of the positive and negative implications of grassy versus wooded riparian zones and discuss potential management outcomes. Compared to wooded areas, grassy riparian areas result in stream reaches with different patterns of bank stability, erosion, channel morphology, cover for fish, terrestrial runoff, hydrology, water temperature, organic matter inputs, primary production, aquatic macroinvertebrates, and fish. Of particular relevance in agricultural regions, grassy riparian areas may be more effective in reducing bank erosion and trapping suspended sediments than wooded areas. Maintenance of grassy riparian vegetation usually requires active management (e.g., mowing, burning, herbicide treatments, and grazing), as successional processes will tend ultimately to favor woody vegetation. Riparian agricultural practices that promote a dense, healthy, grassy turf, such as certain types of intensively managed livestock grazing, have potential to restore degraded stream ecosystems.     

Impact of Native Plants on Bird and Butterfly Biodiversity in Suburban Landscapes

Abstract:  Managed landscapes in which non-native ornamental plants are favored over native vegetation now dominate the United States, particularly east of the Mississippi River. We measured how landscaping with native plants affects the avian and lepidopteran communities on 6 pairs of suburban properties in southeastern Pennsylvania. One property in each pair was landscaped entirely with native plants and the other exhibited a more conventional suburban mixture of plants—a native canopy with non-native groundcover and shrubs. Vegetation sampling confirmed that total plant cover and plant diversity did not differ between treatments, but non-native plant cover was greater on the conventional sites and native plant cover was greater on the native sites. Several avian (abundance, species richness, biomass, and breeding-bird abundance) and larval lepidopteran (abundance and species richness) community parameters were measured from June 2006 to August 2006. Native properties supported significantly more caterpillars and caterpillar species and significantly greater bird abundance, diversity, species richness, biomass, and breeding pairs of native species. Of particular importance is that bird species of regional conservation concern were 8 times more abundant and significantly more diverse on native properties. In our study area, native landscaping positively influenced the avian and lepidopteran carrying capacity of suburbia and provided a mechanism for reducing biodiversity losses in human-dominated landscapes.     

基于主体建模的废物交换模型与仿真分析

作为产业共生中一种重要的关系,废物交换不仅能解决废物处置的难题,还可以降低原料供给的成本与风险. 企业进行废物交换的动力主要来源于经济利益的驱动. 从交换的市场机制出发,运用基于主体建模的方法构建了废物交换的模型框架,并且基于Swarm平台进行了仿真分析. 结果表明:系统的废物交换价格指数在仿真开始后10个周期内迅速降至4左右,并在之后的周期内缓慢下降;系统中单个废物的价格波动较大,但这种波动并未反映到整体的价格指数中;系统中的废物交换量和参与交换的企业数量均呈上升的趋势,但废物交换量的增长呈先慢后快的态势,在第200个周期时达到25×104 t. 而参与交换企业数量的增长呈先快后慢态势并逐渐稳定在100家左右. 示范企业的选取对于系统的废物交换量有一定的影响,选取规模较大的企业作为示范企业比随机选取更能促进系统中的废物交换,在第200个周期时比随机选择下的交换量高出约50%.      

Ecosystem Services as a Common Language for Coastal Ecosystem-Based Management

Abstract:  Ecosystem-based management is logistically and politically challenging because ecosystems are inherently complex and management decisions affect a multitude of groups. Coastal ecosystems, which lie at the interface between marine and terrestrial ecosystems and provide an array of ecosystem services to different groups, aptly illustrate these challenges. Successful ecosystem-based management of coastal ecosystems requires incorporating scientific information and the knowledge and views of interested parties into the decision-making process. Estimating the provision of ecosystem services under alternative management schemes offers a systematic way to incorporate biogeophysical and socioeconomic information and the views of individuals and groups in the policy and management process. Employing ecosystem services as a common language to improve the process of ecosystem-based management presents both benefits and difficulties. Benefits include a transparent method for assessing trade-offs associated with management alternatives, a common set of facts and common currency on which to base negotiations, and improved communication among groups with competing interests or differing worldviews. Yet challenges to this approach remain, including predicting how human interventions will affect ecosystems, how such changes will affect the provision of ecosystem services, and how changes in service provision will affect the welfare of different groups in society. In a case study from Puget Sound, Washington, we illustrate the potential of applying ecosystem services as a common language for ecosystem-based management.     

Basic principles and ecological consequences of changing water regimes on nitrogen cycling in fluvial systems

Understanding the environmental consequences of changing water regimes is a daunting challenge for both resource managers and ecologists. Balancing human demands for fresh water with the needs of the environment for water in appropriate amounts and at the appropriate times are shaping the ways by which this natural resource will be used in the future. Based on past decisions that have rendered many freshwater resources unsuitable for use, we argue that river systems have a fundamental need for appropriate amounts and timing of water to maintain their biophysical integrity. Biophysical integrity is fundamental for the formulation of future sustainable management strategies. This article addresses three basic ecological principles driving the biogeochemical cycle of nitrogen in river systems. These are (1) how the mode of nitrogen delivery affects river ecosystem functioning, (2) how increasing contact between water and soil or sediment increases nitrogen retention and processing, and (3) the role of floods and droughts as important natural events that strongly influence pathways of nitrogen cycling in fluvial systems. New challenges related to the cumulative impact of water regime change, the scale of appraisal of these impacts, and the determination of the impacts due to natural and human changes are discussed. It is suggested that cost of long-term and long-distance cumulative impacts of hydrological changes should be evaluated against short-term economic benefits to determine the real environmental costs.     

Structural Changes in the Carabid Fauna of Forest Ecosystems under a Toxic Impact

Changes in the abundance, species composition, and biomorphological structure of the carabid fauna were studied in birch and fir–spruce forests growing in a zone exposed to emissions from a copper-smelting plant in the Middle Urals. The dynamic density of carabids decreased and their species composition and the ratio of life forms changed along the pollution gradient, but the principle of organization of carabidocenoses and the structure of dominance in them remained undisturbed.     

WATER CONSTRAINTS ON ENERGY DEVELOPMENT: A FRAMEWORK FOR ANALYSIS1

ABSTRACT: The pressure on water resources from energy resource development and transformation is likely to be greater in the future than it has been in the past. A rational resolution of the political problems that this situation will generate requires that: 1) planning based on predictions of future energy supply and demand be replaced by scenario, or “what if?” analysis; 2) full attention be paid to the uncertainties in per-unit-energy water requirements; 3) suitable stochastic measures of water availability be used to compare water supply with water demand; 4) realistic ecological criteria, and other alternative use criteria, be developed for estimating impacts of water withdrawn or consurned for energy development; 5) human consequences of ecological impaccts are described in a manner that will allow the political process to intervene in an optimum manner to allocate water resources.     

Aggregated Estimation of the Basic Parameters of Biological Production and the Carbon Budget of Russian Terrestrial Ecosystems: 1. Stocks of Plant Organic Mass

The data presented were obtained at the first stage (1993–1999) of studies on evaluating the basic parameters of biological production in Russian terrestrial ecosystems in order to provide information for assessing and modeling the carbon budget of the entire terrestrial biota of the country. Stocks of phytomass (by fractions), coarse woody debris, and dead roots (underground necromass) were calculated by two independent methods, which yielded close results. The total amount of phytomass in Russian terrestrial ecosystems was estimated at 81800 Tg (=10¹² g = million t) dry matter, or 39989 Tg carbon. Forest ecosystems comprise a greater part (82.1%) of live plant organic matter (here and below, comparisons are made with respect to the carbon content); natural grasslands and brushwoods account for 8.8%; the phytomass of wetlands (bogs and swamps), for 6.6%; and the phytomass of farmlands, for only 2.5%. Aboveground wood contains approximately two-thirds of the plant carbon (63.8%), and green parts contain 9.9%. For all classes of ecosystems, the proportion of underground phytomass averages 26.7% of the total amount, varying from 22.0% in forests to 57.1% in grasslands and brushwoods. The average phytomass density on lands covered with vegetation (1629.9 million hectares in Russia) is 5.02 kg/m² dry matter, or 2.45 kg C/m². The total amount of carbon in coarse woody debris is 4955 Tg C, and 9180 Tg C are in the underground necromass. In total, the vegetation of Russian terrestrial ecosystems (without litter) contains 54124 Tg carbon.