Table of Content

30 June 2011, Volume 2 Issue 2 Previous Issue    Next Issue

Articles

Ecological Remediation of Hydrocarbon Contaminated Soils with Weed Plant ZHOU Qixing, CAI Zhang, ZHANG Zhineng, LIU Weitao 2011, 2 (2):  97-105.  doi: 10.3969/j.issn.1674-764x.2011.02.001 Abstract ( )   PDF (801KB) ( )   Save Considerable efforts have been undertaken to accelerate the breakdown of existing anthropogenic petroleum hydrocarbons (PHCs) by appropriate in situ remediation technologies. In situ phytoremediation, using higher plants to remove, stabilize, degrade, and/or metabolize hazardous contaminants, has emerged as a promising green technology for cleaning up environments contaminated with PHCs. Weed plants are generally considered to have great potential for use in phytoremediation due to their extensive fibrous root systems and relatively robust characteristics, thus helping establish a strong rhizosphere through contaminated soils. In this review, some important mechanisms involved in phytoremedation of PHC contaminated soils, including phytoaccumulation, phytostabilization, phytodegradation, phytovolatilization, and rhizodegradation, were summarized and discussed. In recent years, a large number of laboratory approaches have been developed to further enhance the phytoremediation efficiency of PHC contaminated soils. The success of these laboratory studies has encouraged researchers to attempt phytoremediation of PHC contaminated soils in the field. However, many limitations still exist in order to successfully apply laboratory experiments to trials in the field. Related Articles | Metrics

Recovery of Vegetation Canopy after Severe Fire in 2000 at the Black Hills National Forest, South Dakota, USA Xiangming XIAO, Chandrashekhar BIRADAR, Audrey WANG, Sage SHELDON, Youmin CHEN 2011, 2 (2):  106-116.  doi: 10.3969/j.issn.1674-764x.2011.02.002 Abstract ( )   PDF (2110KB) ( )   Save Forest fires often result in varying degrees of canopy loss in forested landscapes. The subsequent trajectory of vegetation canopy recovery is important for ecosystem processes because the canopy controls photosynthesis and evapotranspiration. The loss and recovery of a canopy is often measured by leaf area index (LAI) and other vegetation indices that are related to canopy photosynthetic capacity. In this study we used time series imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Terra satellite over the period of 2000–2009 to track the recovery of the vegetation canopy after fire. The Black Hills National Forest, South Dakota, USA experienced an extensive wildfire starting on August 24, 2000 that burned a total area of 33 785 ha, most of which was ponderosa pine forest. The MODIS data show that canopy photosynthetic capacity, as measured by LAI, recovered within 3 years (2001-2003). This recovery was attributed to rapid emergence of understory grass species after the fire event. Satellite-based Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) at the burned sites also recovered within 3 years (2001-2003). Rapid recovery of LAI, NDVI, and EVI at the burned sites makes it difficult to use these variables for identifying and mapping burned sites several years after the fire event. However, the Land Surface Water Index (LSWI), calculated as a normalized ratio between near infrared and shortwave infrared bands (band 2 and band 6 (1628–1652 nm) in MODIS sensor), was able to identify and track the burned sites over the entire period of 2000–2009. This finding opens a window of opportunity to identify and map disturbances using imagery from those sensors with both NIR and SWIR bands, including Landsat 5 TM (dating back to 1984); furthermore, a longer record of disturbance and recovery helps to improve our understanding of disturbance regimes, simulations of forest succession, and the carbon cycle. References | Related Articles | Metrics

Agricultural Land Use Intensity and Its Determinants in Ecologically-vulnerable Areas in North China: A Case Study of Taipusi County, Inner Mongolia Autonomous Region HAO Haiguang, LI Xiubin 2011, 2 (2):  117-125.  doi: 10.3969/j.issn.1674-764x.2011.02.003 Abstract ( )   PDF (783KB) ( )   Save Based on rural household survey data in Taipusi County in Inner Mongolia Autonomous Region, this article analyzes agricultural land use intensity and its determinants. The results reveal marked differences of agricultural land use intensity among households with different ages of householders, proportion of non-farm participants, total agricultural land area, land fragmentation and land utilization capacity. (i) Households with older householders and households with a smaller proportion of non-farming laborers generally spend more time on managing their land and invest less capital and materials than other households. The proportion of non-farming laborers within younger households is relatively high, and they tend to invest more capital and materials because the income derived from non-farm employment relaxes their financial constraints. (ii) Land fragmentation is an important determinant of land use intensity. Households with a bigger land size per plot usually spend less time and invest more capital and materials on their land; (iii) Land with better quality is usually managed intensively. The results suggest that labor has become an important constraint for local agricultural production, and there is the potential to improve land management scale and increase machinery input to substitute for labor. Furthermore, the effects of non-farm employment on land use intensity indicate that the establishment of a coordination mechanism between non-farm employment and agricultural land use is an important way to solve the conflict between ecological security and agricultural production in ecologically-vulnerable areas. References | Related Articles | Metrics

An Investigation of Coal Demand in China Based on the Variable Weight Combination Forecasting Model ZHAO Guohao, GUO Shufen, SHENTU Jing, WANG Yongguang 2011, 2 (2):  126-131.  doi: 10.3969/j.issn.1674-764x.2011.02.004 Abstract ( )   PDF (671KB) ( )   Save Variable weight combination forecasting combines individual forecasting models after giving them proper weights at each time point. Weight is the type of function that changes with forecast time. A relatively rational description of the system can be proposed with the forecasting method, which is of higher precision and better stability. Two individual forecasting models, grey system forecasting and multiple regression forecasting, were generated based on the historical data and influencing factors of coal demand in China from 1981 to 2008. According to the theory of combination forecasting, the variable weight combination forecasting model was formulated to forecast coal demand in China for the next 12 years. References | Related Articles | Metrics

Ecosystem Regulating Services and Their Valuation of Hainan Island, China OUYANG Zhiyun, JIN Yu, ZHAO Tongqian, ZHENG Hua 2011, 2 (2):  132-140.  doi: 10.3969/j.issn.1674-764x.2011.02.005 Abstract ( )   PDF (741KB) ( )   Save Ecosystem services were defined as the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life. They include provisioning, regulating, cultural, and supporting services. These form the basis on which regional environmental reserves and development are assessed and for the valuation of ecosystem services. In this paper Hainan Island is used as an example to explore methods of regulating services based on the structure and processes of a natural ecosystem. Ecosystems were classified into 13 types: valley rain forest, mountainous rain forest, tropical monsoon forest, mountainous coppice forest, mountainous evergreen forest, tropical coniferous forest, shrubs, plantation, timber forest, windbreak forest, mangrove, savanna, and crop land. Regulating services and their economic values for Hainan Island ecosystems were assessed and evaluated in terms of water-holding, soil conservancy, nutrient cycle, C fixation and windbreak functions. The economic value of the regulating services in 2002 were estimated at 2035.88×108 to 2153.39×108 Chinese Yuan (CNY), which was eight times the value of provisioning services (wood and agricultural products), estimated at just 254.06×108 CNY. Our analyses imply that ecosystem regulating services play a very important role in the sustainable development of Hainan Island’s society and economy. References | Related Articles | Metrics

The Effects of Eco-Compensation in the Farming-Pastoral Transitional Zone of Inner Mongolia, China HAN Peng, HUANG Heqing, ZHEN Lin, LI Fen 2011, 2 (2):  141-150.  doi: 10.3969/j.issn.1674-764x.2011.02.006 Abstract ( )   PDF (864KB) ( )   Save Ecological compensation or eco-compensation has been implemented mainly through institutional arrangement in China. In the farming-pastoral transitional zone of Inner Mongolia, eco-compensation has been implemented in two modes, one for land use abandonment and the other for productionstructure adjustment. Based on a detailed field survey, this study performs a comparative analysis of the willingness of households to accept economic compensation and consequently evaluates the effects of the two eco-compensation modes. The mode of eco-compensation for land use abandonment lacks a mechanism for generating employment opportunities and so is unsustainable. In contrast, ecocompensation for production-structure adjustment makes the pastoral and farming scales of households decrease significantly and most importantly helps to generate more job opportunities. Although this mode faces households with more market risk, it provides an effective means for resolving conflicts between ecosystems restoration and regional socio-economic development. References | Related Articles | Metrics

Study on Diversity of Arthropod Community in a Rice-duck Integrated Farming System in South China QIN Zhong, ZHAO Benliang, ZHANG Jia-en, LUO Shiming 2011, 2 (2):  151-157.  doi: 10.3969/j.issn.1674-764x.2011.02.007 Abstract ( )   PDF (940KB) ( )   Save The integration of ducks into rice farming has raised concerns about possible effects on arthropod communities due to frequent predation by ducks. This paper conducted a study using three treatments, including integrated rice-duck cultivation (RD), conventional rice cultivation (CC) and a control treatment (CK), to investigate the impact of rice-duck farming on the diversity of arthropod communities in the field. The results revealed that arthropod numbers in both RD and CC treatments showed varying degrees of reduction when compared with the CK treatment. Arthropod individual numbers, Simpson (D) and Shannon’s diversity index (H' ) values in RD were higher than those in CC. Arthropod individual numbers, richness index (R), D and H' values in both tillering and booting phases of the late rice were significantly higher in RD treatment than those in CC treatment. Rice-duck integration system was favorable for the maintenance of arthropod diversity in the cropping field and may help to lessen the decline in abundance and diversity of rice farmland arthropods caused by the utilization of chemical pesticides and fertilizers. References | Related Articles | Metrics

Analysis of Spatial-Temporal Changes in the Landscape Structure of Yushu Prefecture in Qinghai Province GUO Luo, XUE Dayuan, DU Shihong, HUANG Qi, CAI Liang 2011, 2 (2):  158-161.  doi: 10.3969/j.issn.1674-764x.2011.02.008 Abstract ( )   PDF (1012KB) ( )   Save Yushu Tibetan Autonomous Prefecture, an area located in the Qinghai-Tibet Plateau, is an area very sensitive to global climate change. Due to impacts from climate change and human disturbances, grassland vegetation in the area has been degraded and desertification has been expanding. Ecosystems in the area are very sensitive and fragile and ecological problems have become increasingly serious in the area, resulting in an adverse effect on the local socio-economic development and environment of Qinghai province. Using data gathered from Landsat TM/ETM images for 1987, 1997 and 2007, we analyzed landscape patterns across Yushu Prefecture. Spatial structure indices indicated that: (i) the area of grassland has significantly decreased in the form of degradation and conversion from grassland into bare land and farmland; (ii) grassy vegetation patches changed into fragmented and isolated patches; (iii) the main landscapes in Yushu Prefecture are grasslands, forests and rivers; (iv) patches of grass have relatively high connectivity; and (v) landscape change is significantly correlated with human activities and climate change. This study provides a strong theoretical and technical basis for policy-making regarding environmental protection of and management in Yushu Prefecture of Qinghai Province. References | Related Articles | Metrics

Diversity Centers of Rice Cultivar in Yunnan and Their Correlation with Ecological and Cultural Factors FENG Jianmeng, HE Hanming, GAO Dong, LI Chengyun 2011, 2 (2):  162-167.  doi: 10.3969/j.issn.1674-764x.2011.02.009 Abstract ( )   PDF (1191KB) ( )   Save Ecological and cultural factors have strong impacts on the distribution and cultivation of agricultural cultivar., In this paper, the correlation between diversity centers of rice cultivar and ecological, cultural factors was probed, based on datasets of rice cultivar in Yunnan, Southwest China. The results showed that diversity centers of rice cultivar were observed in Southwest Yunnan, South Yunnan and Southeast Yunnan, which may be related to the local culture of rice production and warm, humid climate. For the diversity center in South Yunnan, culture of rice production of Dai and Hani people may play important roles. The diversity center in Southwest Yunnan may relate to the culture of rice production of Dai, Jingpo and Lahu people, and for the diversity center in Southeast Yunnan, Miao, Yao and Zhuang people’s culture in rice production can not be underestimated. Traditional culture promoted the cultivation of rice cultivars, and high diversity of rice cultivars facilitate the preservation and continuation of the traditional culture as well. References | Related Articles | Metrics

Modeling the Effects of Climate Change and Elevated CO2 on Soil Organic Carbon in an Alpine Steppe LI Xiaojia, ZHANG Xianzhou, ZHANG Yangjian 2011, 2 (2):  168-174.  doi: 10.3969/j.issn.1674-764x.2011.02.010 Abstract ( )   PDF (661KB) ( )   Save The objective of this study was to analyze the effects of climate change and doubled atmospheric CO2 concentrations, as well as the combined effects of climate change and doubling atmospheric CO2 concentrations on soil organic carbon (SOC) in the alpine steppe of the northern Tibetan Plateau using the CENTURY model. The results indicate that SOC loss in climate change scenarios varied from 49.77– 52.36% in the top 20 cm. The simulation results obtained for a P1T0 scenario (increased precipitation and unchanged temperature), P0T1 scenario (unchanged precipitation and increased temperature), and P1T1 scenario (increased precipitation and increased temperature) were similar. The alpine steppe in the P1T1 scenarios lost the greatest amount of SOC (844.40 g C m-2, representing the least amount of SOC) by the end of the simulation. The simulation for P0T1 scenarios resulted in a 49.77% loss of SOC. However, SOC increased 12.87% under the CO2 doubling scenario, compared with the unchanged CO2 scenario. CO2 enhancement effects on SOC were greater than the climate change effects on SOC alone. The simulation of combined climate change and doubling atmospheric CO2 led to a decrease in SOC. This result indicated a decrease of 52.39% in SOC for the P1T1 + 2 × CO2 scenario, 49.81% for the P0T1 + 2 × CO2 scenario, and 52.30% for the P1T0 + 2 × CO2 scenario over the next 50 years. Therefore, SOC content in the alpine steppe will change because of changes in precipitation, temperature and atmospheric CO2 concentrations. References | Related Articles | Metrics

Reports

Causes of Lake Area Changes in Poland Adam CHOINSKI, Agnieszka LAWNICZAK, Mariusz PTAK, Leszek SOBKOWIAK 2011, 2 (2):  175-180.  doi: 10.3969/j.issn.1674-764x.2011.02.011 Abstract ( )   PDF (1174KB) ( )   Save The northern part of Poland is occupied by numerous lakes formed during the last glaciation as a result of the Scandinavian ice sheet. Studies carried out in the lake district areas show progressive reduction of the surface area of the lakes, which leads to their eventual disappearance. The paper discusses the degree of the observed changes and points out main natural and anthropogenic factors influencing changes of lake area in Poland, including climate change, depth of lake basins, biomass growth, deforestation, hydrotechnical works, use of fertilizers and discharge of wastewater. References | Related Articles | Metrics

Geographic Distribution of Avirulence Genes in Rice Blast Fungus in Yunnan Province, China LI Jinbin, YANG Jing, LIU Lin, HE Hanming, HE Xiahong, ZHU Youyong, LI Cheng-yun 2011, 2 (2):  181-185.  doi: 10.3969/j.issn.1674-764x.2011.02.012 Abstract ( )   PDF (687KB) ( )   Save Knowledge of the geographic distribution and frequency of avirulence genes will contribute to the development of strategies to effectively use rice varieties that carry various resistances genes, including combinations of varieties in mixture cropping systems. Here, we analyzed the geographic distribution and frequencies of avirulence genes in rice blast fungus using samples collected from 11 prefectures across Yunnan province, China. A total of 467 single spore isolates were assayed for pathotypes based on their reaction to 20 rice blast resistance monogenic lines. The results revealed that frequencies of avirulence genes among 10 prefectures showed insignificant difference, but frequencies of avirulence genes in Xishuangbanna showed significant differences compared to the remaining 10 prefectures. The avirulence genes Avr-Pi9, Avr-Piz and Avr-Pizt were observed at the highest frequency in blast isolates from the 11 prefectures; their average frequency was greater than 80%. Our results imply that the composition and distribution of rice genetic diversity are more important than climate and other environment conditions for formation and maintenance of rice blast fungus genetic diversity. Using average frequencies, the avirulence genes can be categorized into 4 groups. There were significant differences of frequencies of avirulence genes among different groups, while insignificant differences observed within any group. These results will provide useful information for evaluation of resistance genes and effective management of rice blast disease. References | Related Articles | Metrics

Identifying Alpine Wetlands in the Damqu River Basin in the Source Area of the Yangtze River Using Object-based Classification Method ZHANG Jiping, ZHANG Yili, LIU Linshan, DING Mingjun, ZHANG Xueru 2011, 2 (2):  186-192.  doi: 10.3969/j.issn.1674-764x.2011.02.013 Abstract ( )   PDF (1035KB) ( )   Save Alpine wetlands are very sensitive to global change, have great impacts on the hydrological condition of rivers, and are closely related to peoples’ living in lower reaches. It is essential to monitor alpine wetland changes to appropriately manage and protect wetland resources; however, it is quite difficult to accurately extract such information from remote sensing images due to spectral confusion and arduous field verification. In this study, we identified different wetland types in the Damqu River Basin located in the Yangze River source region from Landsat remote sensing data using the object-based method. In order to ensure the interpretation accuracy of wetland, a digital elevation model (DEM) and its derived data (slope, aspect), Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Kauth-Thomas transformation were considered as the components of the spectral characteristics of wetland types. The spectral characteristics, texture features and spatial structure characteristics of each wetland type were comprehensively analyzed based on the success of image segmentation. The extraction rules for each wetland type were established by determining the thresholds of the spatial, texture and spectral attributes of typical parameter layers according to their histogram statistics. The classification accuracy was assessed using error matrixes and field survey verification data. According to the accuracy assessment, the total accuracy of image classification was 89%. References | Related Articles | Metrics