排序方式: 共有4条查询结果,搜索用时 15 毫秒
1
1.
LI Xiaolin ZHANG Yuanxun TAN Mingguang LIU Jiangfeng BAO Liangman ZHANG Guilin LI Yan IIDA Atsuo 《环境科学学报(英文版)》2009,21(8):1118-1124
The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites (6 traffic, 5 industrial, and 6 residential sites), and 3 suburban sites to assess the lead pollution in fine particulate matter (PM2.5) after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range (213–176 ng/m3) in PM2.5 in winter. Significant spati... 相似文献
2.
对比研究了隧道和大气环境中不同粒径细颗粒物 (切割粒径分别为0.03,0.06,0.108,0.17,0.26,0.40,0.65,1.0,1.6和2.5 μm) 中S,K,Ca,Ti,Mn,Fe,Zn,Pb,Al,Si,Cu和V等12种痕量元素的浓度. 结果表明:隧道中不同粒径细颗粒物的数浓度和质量浓度在上下班高峰时段出现明显峰值,且隧道细颗粒物在0.108 μm粒径处的数浓度和在2.5 μm粒径处的质量浓度分别是大气环境对照值的15.2和40.0倍;在隧道传输过程中质量浓度增加的痕量元素有 Si,Ca,Fe,Al,Ti,Zn,Mn,Cu和V,减小的有S,Pb,Zn和K;地壳元素(Si,Ca,Fe,Al和Ti)的质量浓度总和占隧道细颗粒物中痕量元素质量浓度总和的87%,表明土壤扬尘仍是隧道大气细颗粒物的主要来源. 相似文献
3.
YUICHI YAMAURA TAKAYUKI KAWAHARA SHIGEO IIDA KENICHI OZAKI 《Conservation biology》2008,22(6):1513-1522
Abstract: Although enhancing reserve shape has been suggested as an alternative to enlarging nature reserves, the importance of reserve shape relative to reserve area remains unclear. Here we examined the relative importance of area and shape of forest patches to species richness, species composition, and species abundance (abundance of each species) for 3 taxa (33 birds, 41 butterflies, and 91 forest‐floor plants) in a fragmented landscape in central Hokkaido, northern Japan. We grouped the species according to their potential edge responses (interior‐, neutral‐, and edge‐species groups for birds and forest‐floor plants, woodland‐ and open‐land‐species groups for butterflies) and analyzed them separately. We used a shape index that was independent of area as an index of shape circularization. Hierarchical partitioning and variation partitioning revealed that patch area was generally more important than patch shape for species richness and species composition of birds and butterflies. For forest‐floor plants, effects of patch area and shape were small, whereas effects of local forest structure were large. Patch area and circularization generally increased abundances of interior species of birds and forest‐floor plants and woodland species of butterflies. Nevertheless, only patch circularization increased abundances of 1 woodland species of butterfly and 2 and 6 interior species of birds and forest‐floor plants, respectively. We did not find any significant interaction effects between patch area and shape. Our results suggest that although reserves generally should be large and circular, there is a trade‐off between patch area and shape, which should be taken into consideration when managing reserves. 相似文献
4.
KENICHI OZAKI† MASAHIRO ISONO† TAKAYUKI KAWAHARA† SHIGEO IIDA† TAKUMA KUDO† KENJI FUKUYAMA† 《Conservation biology》2006,20(5):1507-1515
Abstract: Although species with large area requirements are sometimes used as umbrella species, their general utility as conservation tools is uncertain. We surveyed the species diversity of birds, butterflies, carabids, and forest-floor plants in forest sites across an area (1600 km2 ) in which we delineated large breeding home ranges of Northern Goshawk ( Accipiter gentilis ). We tested whether protection of the home ranges could serve as an effective umbrella to protect sympatric species of the four taxa. We also used an empirical habitat model of occupancy of home range to examine mechanisms by which the Northern Goshawk acts as an umbrella species. Among species richness, abundance, and species composition of the four taxa, only abundance and species composition of birds differed between sites located inside and outside home ranges, which was due to greater abundance of bird species that were prey of Northern Goshawks inside the home ranges. Thus, although home range indicated areas with high abundance of certain bird prey species, it was not effective as an indicator of the species diversity of all four taxa. We also did not find any difference in species richness, abundance, and species composition between sites predicted as occupied and unoccupied using the habitat model. In contrast, when we selected sites on the basis of each habitat variable in the model, habitat variables that selected sites either in agricultural or forested landscapes encompassed sites with high species richness or particular species composition. This result suggests that the low performance of the Northern Goshawk as an umbrella species is due to this species' preference for habitat in both agricultural and forested landscapes. Species that can adjust to changes in habitat conditions may not act as effective umbrella species despite having large home ranges. 相似文献
1