As wildlife habitat is in constant evolution, periodic monitoring is essential to assess its quality. In this study, the change to the red-crowned crane habitat in the Yellow River Delta Nature Reserve was detected from multi-temporal remote sensing data from 1992 to 2008 in a geographic information system. Habitat fragmentation was derived from both physical constraints and human disturbance. The changing habitat quality was assessed against five landscape indices. The results obtained from Landsat TM images indicate that potential habitat shrank 37.9 % during 1992–2001, but recovered 99.4 % by 2008. Suitable habitat shrank by 4,329 ha to a level below that of 1992 despite an increase of 4,747 ha in potential habitat due to an increase of 9,075 ha in fragmented areas. Both landscape indices and the red-crowned crane population reveal that suitable habitat was the most fragmented in 2001, but the least fragmented in 1992. Therefore, it is inadequate to just restore wetland through artificial diversion of channel flow to the Reserve to preserve the crane habitat. Commensurate efforts should also be directed at improving habitat quality by minimizing human activities and spatially juxtaposing water and reed marshes harmoniously inside the Reserve. 相似文献
The suitable spectral mode in remote sensing is often desirable to facilitate the inversion of ecological environment and landscape. This paper put forward an optimizing model based on variable precision rough sets (VPRS) for the land cover discrimination in wetland inventory. In the case study of Lake Baiyangdian which has important ecological functions to the northern China, this model is established successfully according to the domain-experts knowledge. The procedure is as follows. First step is data collection, including remote-sensing data (e.g., Landsat-5 TM bands), the digitized relief maps, and statistical yearbooks. Second, the remote sensing imagery (RSI) and relief maps are co-registered into the same resolution. Third, a condition set, including various attributes is derived from spectral bands, band math or ratio indices based on previous studies, at the same time, the decision set is derived from true land types after investigation and validation. Then, the remote sensing decision table (RSDT) is constructed by linking condition set with decision set according to the sequential pixels in RSI. Fourth, we create one forward greedy searching algorithm based on VPRS to handle this RSDT. After adjusting parameters such as β and knowledge granularity diameter (KGD), we obtain the stable optimized results. Comparative experiments and evaluation show that the discrimination or retrieval accuracy of VPRS model is satisfying (overall accuracy: 87.32% and KHAT: 0.84) and better than original data. Moreover, data dimension has been decreased dramatically (from 12 to 3) and key attributes found by the model may be useful for specific retrieval in wetland inventories. 相似文献
Surface water, suspended particulate matter, pore water, and sediment samples were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) in Yongding New River, South Drainage Canal and North Drainage Canal, which receive most of wastewater from industrial city of Tianjin. PAH concentrations in effluent samples of wastewater treatment plants (WTP) discharging into the South Drainage Canal and North Drainage Canal were quantified for the first time. The results showed that the discharge of the WTPs recently only contributed to the PAH contamination in the canals near the outlets of the WTPs. PAH levels in sediments of the streams were greatly higher than those in soils by riverbank probably due to receiving large amounts of untreated wastewater. Unusually high benz[a] anthracene concentration strongly influenced the seasonal and spatial variation of total PAH concentrations in South Drainage Canal. Paired samples t test of ??Nap, Fl, Phe, Fluo and ??Nap, Phe, Fluo, Chry concentrations, which were dominant components in the air samples from non-heating and heating season, respectively, in the suspended particulate matters from the streams showed that PAH source from air deposition was more important for Yongding New River than that for South Drainage Canal and North Drainage Canal. Source apportionment based on PAH profiles indicated that coal combustion was the major PAH contamination source, and coke oven sources and wood combustion also contributed to the PAH contamination of the streams. This was further indicated by organic petrography analysis. 相似文献
Polycyclic aromatic hydrocarbons(PAHs) and their nitrated derivatives(NPAHs) attract continuous attention due to their outstanding carcinogenicity and mutagenicity. In order to investigate the diurnal variations, sources, formation mechanism, and health risk assessment of them in heating season, particulate matter(PM) were collected in Beijing urban area from December 26, 2017 to January 17, 2018. PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS). ... 相似文献
Herein, Na+ and Ca2+ are introduced to MnO2 through cation-exchange method. The presence of Na+ and Ca2+ significantly enhance the catalytic activity of MnO2 in toluene oxidation. Among them, the Ca-MnO2 catalyst exhibits the best catalytic activity (T50 = 194°C, T90 = 215°C, Ea = 57.2 kJ/mol, reaction rate 8.40 × 10?10 mol/(sec?m2) at 210°C. T50 and T90: the temperature of 50% and 90% toluene conversion; Ea: apparent activation energy) and possess high tolerance against 2.0 vol.% water vapor. Results reveal that the increased acidic sites of the MnO2 sample can enhance the adsorption of gaseous toluene, and the mobility of oxygen species and the content of reactive oxygen species in the catalyst are significantly improved due to the formed oxygen vacancy. Thus these two factors result in excellent catalytic performance for toluene oxidation combining with the weak CO2 adsorption ability. 相似文献
Environmental Science and Pollution Research - Alkyl polyglycosides (APG), a biodegradable biosurfactant, have been widely used in environmental pollution control. However, the application of APG... 相似文献
As the digital economy develops rapidly and the network information technology advances, new development models represented by the network economy have emerged, which have a crucial impact on green economic growth. However, the relevant previous studies lacked the role of analyzing the direct and indirect effects of internet development on green economic growth at the prefecture-level city level. For this purpose, this paper aims to examine the intrinsic mechanism of the impact of internet development on green economic growth and provide empirical support for cities and regions in China to increase internet construction. Furthermore, the mixed model (EBM), which includes both radial and non-radial distance functions, is applied to calculate the green economic growth index. Fixed effect model and mediation effect model are also employed to test influence mechanisms of the internet development on green economic growth using panel data of 269 prefecture-level cities in China from 2004 to 2019. The statistical results reveal that internet development has contributed significantly to green economic growth. When the internet development level increases by 1 unit, the green economic growth level increases by an average of 5.0372 units. However, regional heterogeneity is evident between internet development and green economic growth, that is, the promoting effect of internet development on green economic growth is gradually enhanced from the eastern region to the western region. We also find that internet development guides industrial structure upgrading improves environmental quality and accelerates enterprise innovation, which indirectly contributes to green economic growth. And internet development mainly achieves green economic growth through enterprise innovation. Based on the above findings, we concluded that policymakers should not only strengthen the guiding role of social actors to promote the stable development of the internet industry, but also foster the construction of the three models of “internet+industry integration,” “internet+environmental governance,” and “internet+enterprise innovation” to promote green economic growth.