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Mining activities produced a lot of abandoned mine land. This paper introduced the theoretical and technical progress of ecological restoration of surface coal mines, mining subsidence land and coal waste piles in China and discussed some key problems for research in the future. Ecological restoration of abandoned mine land was related to many disciplines, and multi—disciplinary theories might make great contributes to it. Some practical techniques of ecological restoration of abandoned mine land and their demonstration bases in China were introduced. Ecosystem succession process and mechanism, structure optimization of land use and new technologies of ecological restoration of abandoned mine land should be focused on in research activities.
An ecotone is a transition area between two biomes or two different ecosystems and are often fragile, sensitive and variable. Since the 1970s, the study of the ecotone has increasingly gained notoriety as an important facet of ecological research. China, with a vast complex geology, climate and vegetation, is home to a variety of ecotones. This variety is witnessed in breeds, scales and sizes. This vast array has not only laid a solid foundation for scientific research but also enhanced China's economic development, social development and cultural diversity conservation. According to the geographical distribution and ecological features of China's large scale ecotone, “The trinity index system” has been established including land use types, natural climate characteristics and agricultural economic development to classify and define the spatial distribution of typical ecotones in China. Based on this classification, the natural environmental characteristics, environmental fragility and the existing problems of five kinds of typical ecotones have been studied. This study will lead to a comprehensive understanding of the evolutionary patterns of ecotones.
We examined stable isotope signals of precipitation, soil water, and xylem water and ran the multi-source linear mixing model (IsoSource) to determine water uptake depths and estimate proportional contribution of possible water pools to the water use of Mongolian pine (Pinus sylvestris var. mongolica) plantation in southeast Horqin Sandy Land. We also examined variations of the water use by Mongolian pine trees before and after a heavy precipitation event. The closeness of isotopic composition between xylem water and potential water pools presented that most of water uptake by the trees occurred in the depth of below 20 cm soil (up to 80 cm in this study). Estimate from the IsoSource model agrees well with observation, and the model yielded that over 60% of the water was derived from 20–80 cm soil layer under relatively higher soil moisture conditions, contribution from much deeper soil depth may increase when the soil in this layer became dry. The contribution from the groundwater was very low since water table was much deeper than rooting depth of the trees. Isotopic signals of xylem water of Mongolian pine trees before and after a heavy precipitation of 14.4 mm on July 13 in 2009 exhibited that the trees could sense and use recent rain-charged soil water at the upper 20 cm soil layer 36 hours after the rain, and this contribution decreased rapidly in the following 24 hours. The ability of accessing different water pools of Mongolian pine trees under various soil moisture conditions is likely a good indicator of their adaptability to dry habitats in sandy lands.
Wuliangsuhai wetland is one of the representative wetlands in arid—semiarid region. It is also a key breeding site as well as a stepping site for both East Asia—Australasia Flyway and Central Asia Flyway. From 2009 to 2012, surveys on migratory water birds and their habitat were carried out by using transects census and spot count methods. The surveys recorded more than 100 000 water birds, and 98 species were identified, which belong to 6 orders and 14 families. Among the 98 species, 55 are summer residents (breeding here) and 39 are travelers (only stay here shortly), which account for 56.12% and 39.80% of the total recorded bird species respectively. Further analysis on their migration pattern shows that spring migration is mainly from early March to mid May, which is shorter than autumn migration season (from early August to mid November). Most of the summer residents breed from early April to late May. High concentration of key protected species were observed from early April to early May and from early September to early November. The bird community structure is relatively stable in summer, but much more dynamic during the migration seasons (spring and autumn). Based on the study, recommendation to nominate Wuliangsuhai wetlands as Ramsar site, and flyway network site were put forward. Habitat management that address to the environmental determinants on bird distribution was also discussed.
In this article, we calculate mainland China's CO2 emission of fossil fuel consumption from 1991 to 2010 following the apparent consumption method recommend by IPCC: (i) the scale of CO2 emissions has increased nearly to 4 times as that in 1991; (ii) coal consumption constitutes the highest proportion due to the richness of coal resources in China; (iii) per capita CO2 emission has increased from 1.98 to 5.57 t CO2; (iv) carbon emission intensity declined significantly from 6.66 to 1.07 kg CO2 USD-1, but recently it tends to be stable; and (v) regional develop gaps remain in mainland China, for according to the provincial data, in many developing regions economic increase over-reliance on fossil fuel consumption. China has made the promises and already taken actions to deal with the high carbon emission. Comprehensively considering the sustainability of development and the uncertainties remaining in global climate change, healthier structures of industry, intensive usage of fossil fuel, and a more balanced development pattern among the southern, central and western China should be put more emphasis.
Mulberry is a perennial and broadleaf woody plant. Mulberry trees have long been cultivated for silkworm rearing. In recent years, the roles of mulberry trees in the prevention and control of desertification, water and soil conservation, saline—land management and returning the grain plots to forestry have been identified. Meanwhile, multi usage of mulberry as forage for livestock, for fruit and tea preparation has been gradually explored. Therefore, an innovation occurred in the mulberry industry. This article introduces the ecological and economic values of mulberry trees, the applications of mulberry, and the development of mulberry industry.
This paper analyzed time-series variation and spatial distribution characteristics of wind resources at the eastern edge of Qaidam Basin based on the wind resources gradient automatic observation system. Wind resources are relatively abundant in the study area, the cumulative number of hours of wind speed between 3–25 m s-1 are more than 6600, equal to 275 days, exceeding 75% of total annual hours. Advantage wind velocity spectrum was in the scope of 3–9 m s-1 at all gradients and the peak value of wind speed was 4–6 m s-1. Differences in the wind speed frequency distribution at other gradients were not apparent except for the 10 m gradient. Compared with other layers, the occurrence frequency of small wind at the level of 10 m was higher, while the occurrence frequency of wind speed between 6 and 12 m s-1 was higher at other layers. The advantage wind direction in this area was northwest and the wind speed difference was not obvious. Wind speed and wind power density gradually increased with the increasing height, and differences among sites were apparent. The average wind turbulence intensity was 0.199 at each layer and the average shear index was 0.075; turbulence intensity and shear index gradually reduced from over a 10–70 m gradient. Turbulence intensity had the same variation tendency as local temperature, whereby a high temperature corresponded to high turbulence and low temperature to low turbulence. The variation tendency of shear index was opposite to that for turbulence intensity; turbulence intensity gradually decreased from lower layers to top layers and shear index was most obvious between 10–30 m. Turbulence intensity at each site at each level was between 0.10–0.25, and of medium intensity. These data will provide a technical gist for the layout of wind farms and the utilization of wind power resource at ground level throughout the study region.
In many regions both urban expansion and rural development take place simultaneously, and for the purpose of understanding the dynamic process of land use/cover change (LUCC) in such large areas, this study develops a multi—agent based land use model. Taking the Poyang Lake area of China as a typical case, this study applies the mechanism of diffusion—limited aggregation to simulate the behavior of urban agents, while rural land use is illustrated with a bottom—up based model consisting of agent and environment layers. In the agent layer, each household agent makes its own decisions on land use, and at each time interval a government agent takes control of land use by implementing policies. According to incomes and the rate of migrant workers, household agents are divided into six categories, among which different decision rules are followed. For complex LUCC in the Poyang Lake area of China from 1985 to 2005, the artificial society model developed in this study yields results highly consistent with observations. Importantly, it is shown that governmental policies can impose significant effects on the decisions of individual household agents on land use and the multi—agent—based land use model developed in this study provides a robust means for assessing the effectiveness of governmental policies.
This study evaluated Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) product i.e. TRMM 3B42 data, using data from 52 rain gauge stations around the Meichuan watershed, which is a representative watershed of Poyang Lake basin in China. Both the latest Version 7 (V7) and previous Version 6 (V6) of TRMM 3B42 data were compared and evaluated for a 9-year period covering 2001–2005 and 2007–2010. The evaluations were conducted at different spatial (grid and watershed) and temporal (daily, monthly and annual) scales. For evaluation at grid scale, the Thiessen polygon method was used to transform pointed-based rain gauge data to areal precipitation at the same grid scale (0.25°) as TRMM 3B42 data. The results showed that there was little difference in performances of V6 and V7 TRMM 3B42 products. Overall, both V6 and V7 products slightly overestimated precipitation with a bias of 0.04. At daily scale, both V6 and V7 data were considered to be unreliable with large relative RMSE (135%–199%) at the two spatial scales, and they were deficient in capturing large storms. These results suggest that local calibration with rain gauge data should be conducted before V6 and V7 TRMM 3B42 data are used at daily scale. At monthly and annual scales, V6 and V7 TRMM 3B42 data match the rain gauge data well (R2 = 0.91–0.99, relative RMSE = 4%–23%) at both grid and watershed scale and thus have good potential for hydrological applications.
In this paper, ecological footprint methods were used to calculate the ecological footprint of six cities (Nanchang, Jingdezhen, Jiujiang, Xinyu, Yingtan and Fuzhou) in the Poyang Lake Area, Jiangxi, China from 1991 to 2010. Ecological footprint was the input factor for ecological resources and the contribution of this and other factors such as labor and capital to economic growth were analyzed. The results showed that, from 1991 to 2010, ecological footprints in the six cities increased year by year. The amount of land for fossil energy, under cultivation and grassland influenced total ecological footprint in each city. The contribution of ecological resources, labor factors and capital factors to economic growth showed regional differences. Nanchang, Jiujiang, Xinyu, and Yingtan are capital—orientated and capital factor had a great influence on the economic growth rates, whereas, Jingdezhen and Fuzhou were labor—orientated. The contribution of ecological resources to economic growth in the six cities was the lowest of all three factors, meaning that efficiency of ecological resource utilization is low. Total productivity plays a key role in economic development; however, the overall level of total factor productivity for the six cities was low and indicates that the technological content of Poyang Lake Area's economic growth is low and the utilization of input factors extensive. In summary, we suggest changing the mode of economic growth and developing tertiary industry in the region.
How to best use farmland contaminated with low to moderate levels of heavy metals remains a challenge in many parts of the world. Here, we screened sugar cane varieties to identify those with a low ability to accumulate heavy metals and with high tolerance. These trials were conducted in arsenic (As), lead (Pb) and Cadmium (Cd) contaminated farmland in IIuanjiang County, Guangxi Zhuang Autonomous Region, China. We tested seven varieties and found that cultivar Guiyin9 had the highest cane stem yield (187.5 t ha-1) and sugar content (27 t ha-1). The concentrations of As, Pb and Cd in the cane juice of Guiyin9 were all below the maximum limit for contaminants in food. Because Guiyin9 showed low accumulation of the heavy metals tested here and produced a high cane stem yield, this cultivar could be planted as a valuable crop in large areas of southern China contaminated with low to moderate levels of heavy metals.
Understanding the amount of instantaneous peak flow in watersheds is one of the most important factors that plays important role in planning and designing of projects related to water and river engineering. The purpose of this study is to compare the efficiency of artificial neural network and empirical methods for estimating instantaneous peak flow in Kharestan Watershed located northwest of Fars Province, Iran. For this purpose, 25 years of daily peak and instantaneous peak flow of Jamal Beig Hydrometrie Station was considered. Then the estimation was done based on empirical methods including Fuller, Sangal and Fill—Steiner and artificial neural network and were compared based on RMSE and R2 . Results showed that estimation of artificial neural network is more accurate than empirical methods with RMSE = 13.710 and R2 = 0.942 which indicated the lower errors of artificial neural network method compared with empirical methods.
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