Pilot investigations of surface parts of three closed landfills and factors affecting them

Aftercare of closed sanitary landfills in a major environmentalproblem. Rehabilitation of the landfill with vegetation and reducing leachate production are two issues that must be dealt.For this reason, Finnish Environment Institute has conducted several projects on closed landfills. This research aims atdetermining the physical and chemical properties of the soils atthree closed landfills in Helsinki, Finland. Research was conducted to understand the impact by studying the following properties: Chemical, nutrient metal, gamma and radon analysis of surface soils of three closed landfills in Helsinki area.     

Modeling distribution changes of vegetation in China under future climate change

Climatic change will result in great changes in vegetation. In this paper, a biogeographical model, the BIOME1, was used to predict potential vegetation distribution in China under climate change. Firstly, the BIOME1 was validated according to the climate–vegetation relationships in China. Kappa statistics showed that the validated BIOME1 was able to capture the geographical patterns of vegetation more accurately. Then, the validated BIOME1 was used to predict the distribution of vegetation of China under two climatic scenarios produced by a Regional Circulation Model, RegCM2/CN. The simulation results showed obvious northward shifts of the boreal, temperate deciduous and evergreen and tropical forests, a large expansion of tropical dry forest/savanna and reduction of tundra on the Tibetan Plateau. Three vulnerable regions sensitive to climate changes are pointed out, i.e., Northern China, the Tibetan Plateau and Southwestern China (mainly Hengduan Mountains in Yunnan Province and west of Sichuan Province). In recent decades, China has experienced dramatic industrialization and population growth, which exert strong pressure on the environment of China. The consequences of climate changes warrant more attention for maintaining a sustainable environment for China.     

利用植被改善博斯腾湖生态环境

博斯腾湖是我国最大的内陆淡水湖，具有重要的生态地位，然而受人类活动的严重干扰，已变成微咸湖，且受到一定的有机污染，其生态环境遭到严重破坏，加强对博斯腾湖的保护和综合利用，已迫在眉睫，针对博斯腾湖的现状，笔者认为必须对其进行综合治理，充分利用植被，才能确保湖区资源的持续利用。可考虑采用下列措施：（1）合理利用水资源；（2）在湖周围发展荒漠植被，乔，灌，草相结合，可选择胡杨，柽柳，沙刺，梭梭，沙棘等种类；（3）保护芦苇植被，大力发展其他水生植物，研究表明，水面上有水生植物生长时，其蒸发蒸腾量低于自由水面的蒸发理，而且降低了水体的矿化度并净化了水体，并且可为养殖业提供大量优质饲料，利用植被改善博斯腾湖的生态环境，投资少，效益明显而持久。     

炼油厂外排污水回用于绿化的研究初探

实验选用三种不同的源水,即大港地区的地下水、滦河水和炼油厂外排水,实验植物选用:一串红、藿香蓟。定期分别用三种源水浇灌植物,以考察两种植物生长情况和土壤离子浓度的变化。研究结果表明,炼油废水处理后用于绿化,在达标排放的情况下,对某些植物的生长有一定的促进作用。     

西北地区生态用水的探讨

我国西北地区多处于干旱气候带，水资源匮乏，生态环境脆弱。为实施西北地区生态恢复与重建，必须合理开发和利用该区有限的水资源，科学地确定社会用水同生态用水的比例，积极保证生态用水，合理利用生态用水，注重生态用水的多重效益。结合西北干旱区实际情况，就这一地区生态用水的开发和利用做了分析阐述。     

A Special Vegetation Index for the Weed Detection in Sensor Based Precision Agriculture

Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations. The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications. The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection on mulched croplands. Experimental investigations in weed detection on mulched areas point out that the DIRT performs better than the Normalized Difference Vegetation Index (NDVI). The result of the evaluation with four different decision criteria indicate, that the new DIRT gives the highest reliability in weed/background differentiation on mulched areas. While using the same spectral bands (infrared and red) as the NDVI, the new DIRT is more suitable for weed detection than the other vegetation indices and requires only a small amount of additional calculation power. The new vegetation index DIRT was tested on mulched areas during automatic ratings with a special weed camera system. The test results compare the new DIRT and three other decision criteria: the difference between infrared and red intensity (Diff), the soil-adjusted quotient between infrared and red intensity (Quotient) and the NDVI. The decision criteria were compared with the definition of a worse case decision quality parameter Q, suitable for mulched croplands. Although this new index DIRT needs further testing, the index seems to be a good decision criterion for the weed detection on mulched areas and should also be useful for other image processing applications in precision agriculture. The weed detection hardware and the PC program for the weed image processing were developed with funds from the German Federal Ministry of Education and Research (BMBF).     

Field Surveys of Ozone Symptoms on Spontaneous Vegetation. Limitations and Potentialities of the European Programme

Within the European intensive forest monitoring programme, the native vegetation on permanent Level II plots has been monitored for visible ozone injuries. The main purpose of the programme is to assess the potential risks for the forest vegetation and the natural ecosystems at the intensive monitoring plots. During the first years of the programme the surveys were qualitative, reporting only the number and the name of the symptomatic species in selected Light Exposed Sampling Site. In 2003 a new plot design was tested, based on the distribution of a number of miniplots along the edge of the forest, so as to obtain quantitative findings about the occurrence and distribution of the symptoms. The problems that still persist are related to: (i) the forest edge assessed for ozone symptoms may have a different floristic composition from the Level II plot itself; (ii) the anthropic pressure and the disturbances affecting the forest edge alters the floristic composition; (iii) the variability of the plant composition in the forest edge, which makes comparability difficult between different sites; and (iv) the evaluation of symptoms in several species that have not yet been experimentally tested. Further difficulties are due to the fact that symptoms observed in the field are often aspecific and cannot, therefore, be attributed solely to the phytotoxic action of ozone. To improve the effectiveness of the European programme, it is necessary: (i) to individualise and select common sensitive plant species for homogeneous ecological regions; (ii) to enhance experimental activities to test the sensitivity of a large number of plant species.     

Assessment Of Trampling Simulation Impacts On Native Vegetation In Mediterranean Sclerophyllous Forest

This study examines the effects of visitors on vegetation of natural semi-arid areas of Mediterranean basin using controlled experimental trampling. Impacts were assessed on days 1, 5, 15 and 30 examining presence of plant species, their cover and height in linear transects suffering a constant trampling intensity (25, 75, 100 and 200 passes/day). In addition, the study included the analysis of factors such as plant species, trampling intensity, the cumulative impact (day effect) and the type of footwear on plant variables. The results showed a decrease on plant cover and height influenced by cumulative (day) effect, an effect of trampling intensity and a different effect for each species. In contrast, shoe type affected only slightly the decrease in plant height. The evolution of plant cover revealed which species were most resistant to trampling. The disappearance of plant individuals during trampling appeared to be an impact index better than plant cover, because cover increased in some species when they were trampled thus introducing a bias.     

Macrobenthic Monitoring in the Lower St. Johns River, Florida

The macrobenthos in the oligohaline 132 km reach of the Lower St. Johns River, Florida, is an unusual blend of freshwater and marine organisms within the annelid, mollusk, aquatic insect, and crustacean groups. During 1993–1994, the community composition was freshwater-oriented in the 47 km (seg I) and estuarine-dominated in the lower 85 km (seg II). Of the total 146 taxa collected, 89% were euryecious 'eutrophic' and 'pollution-tolerant' organisms. Densities ranged between 5000 and 20 000 individuals/m² ann av and maximum densities (85 000 individuals/m²) occurred in the muck substrate at the confluence of major tributaries and embayments. Throughout the lake-like seg II, benthic hypoxia existed during much of summer through fall. Biotic index values for grab, artificial substrate, and sled trawl samples reflected greatest stresses to the macrobenthos then. Both low taxonomic diversity and densities of organisms at the most downriver stations nearest the port of Jacksonville indicated that toxic substances also adversely affected the macrobenthos. Maintenance of the narrow band of littoral submerged aquatic vegetation (SAV) and adjacent shoreline riparian vegetation is important to sustain macrobenthic communities and other kinds of aquatic life in the river.     

The Natural Vegetation Responses to the Groundwater Change Resulting from Ecological Water Conveyances to the Lower Tarim River

This paper takes the ecological water conveyance project (EWCP) that transfers water from the Bosten Lake, to Daxihaizi Reservoir, and finally to the Taitema Lake as a case study to analyze the dynamic change of the groundwater depth, the vegetation responses to the elevation of the groundwater depth as well as the relationship between the groundwater depth and the natural vegetation. The results from many years’ monitoring in field indicate: (1) the groundwater depth has been elevating gradually with the increase in the times of watering and the elevation range has been expanding continuously in the lower reaches of Tarim River. Correspondingly, the natural vegetation has a favorable response to the elevation of the groundwater depth. The change of the natural vegetation has accordance with that of the groundwater depth. Such facts not only show that groundwater is a key factor to the growth of the native vegetation but also prove it is feasible that the degraded ecosystem can be restored and protected by the EWCP; (2) the results of analysis of the spatial-temporal response of the natural vegetation to watering reveals that the beneficial influence of the EWCP on the ecosystem in the lower Tarim River is a long-term process; (3) in terms of the function and structure of ecosystem after watering in the lower reaches of Tarim River, the EWCP does not still reach the goal of ecological restoration at a large spatial scale at present. Based on such monitoring results, some countermeasures and suggestions for the future restoration strategy are proposed so as to provide a theoretical basis for restoring and protecting the ecosystem in Tarim River, and meanwhile it can also provide some scientific references for implementing the similar ecological projects in other areas.