首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13篇
  免费   0篇
  国内免费   1篇
综合类   4篇
基础理论   4篇
污染及防治   3篇
社会与环境   3篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2018年   1篇
  2017年   1篇
  2015年   2篇
  2014年   2篇
  2012年   1篇
  2010年   1篇
  2008年   1篇
  2007年   1篇
排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
2.
3.
Regional Environmental Change - Across the country, government agencies increasingly collaborate with non-governmental actors on environmental dilemmas to gain access to resources, expertise, and...  相似文献   
4.
PAH concentrations have been determined in 47 seasonal snowpack samples collected in the Valbelluna valley and in the Bellunesi Dolomites National Park, in the Italian North-Eastern Alps, during the winter of 2005. The ΣPAH concentration in high-altitude alpine sites (above 1700 m) was 32 ± 20 ng/kg while in valley bottom urban areas it was 165 ± 54 ng/kg with maximum values of 290 ng/kg. The GIS mapping technique was employed to produce a PAH spatial distribution. The urbanized Valbelluna valley, and in particular the SW part, had the highest accumulation of all PAH, with values an order of magnitude more than those in rural and alpine areas. This behaviour is consistent with urban air quality data, and is due to geo-morphological and meteorological factors such as the deeper shape of the valley at the position of the town of Feltre and the low altitude of the boundary layer during the winter season.  相似文献   
5.
To adequately describe seasonal rhythms in habitat utilization by fish communities, observations are needed that occur at a relatively high frequency and over large temporal windows. For the first time, images collected from a cabled video-observatory (the western Mediterranean expandable SEAfloor OBservatory; OBSEA) were utilized to examine habitat utilization by coastal fishes. Over the course of a year, hourly digital images of the water column and an artificial reef were obtained during daylight hours. For each image, the total number of species, an estimate of the abundance of individuals, and the Shannon Diversity Index were quantified. A total of 22 fish species commonly associated with nearshore western Mediterranean habitats were identified, and significant spatial (water column vs. artificial reef), seasonal (spring, summer, autumn, and winter), and daily (morning, midday, and sunset) differences in habitat utilization occurred. Four species (Diplodus vulgaris, Diplodus cervinus, Diplodus sargus, and Scorpaena porcus) were associated with the artificial reef, while one species (Pagrus pagrus) chiefly occurred in the water column. Chromis chromis and Diplodus annularis occurred at the site more frequently in the winter and autumn, respectively, while 14 other species utilized the site more frequently in either the spring (8 spp) or summer (6 spp). In addition, Dentex dentex and Spicara maena occurred more frequently at sunset, while D. cervinus displayed a crepuscular rhythm (occurring more frequently in the morning and at sunset). Species diversity was highest in the summer and lowest in the winter. If not taken into account when planning in situ sampling, such seasonal and/or diel differences may lead to spurious estimates of population sizes and biodiversity. We suggest that cabled video-observatories offer a non-invasive and reliable technology for faunistic sampling and population assessment in coastal water of the Mediterranean and likely elsewhere.  相似文献   
6.
7.
Environmental Science and Pollution Research - Male fertility and semen quality have declined over recent decades. Among other causes, exposure to environmental and occupational pollution has been...  相似文献   
8.
9.
The red fox (Vulpes vulpes) is generally considered a pest species, especially in rural habitats where it is perceived as a predator of livestock and game species. In many countries, population-control programs are carried out to prevent predation on species of human concern. However, most of these programs occur without an analysis of the real fox impact. This study analyzed the diet of red foxes inhabiting a farmland area characterized by the presence of both free-ranging livestock and game species. We analyzed a total of 147 scats belonging to 32 food samples. Invertebrates represented the main food category (recorded on 66% of food samples), followed by fruit and small mammals, both recorded on 59% of food samples. The seasonal variation of the diet matched the availability of food resources, as demonstrated by the outcome of small mammal trapping activity in the area. The livestock consumption regarded almost exclusively carrions, since only hair of adult sheep were recorded with high frequency. Wild boar hair were found in two food samples, lamb and hare hair were found in only one. Our study showed an easy protocol to assess the role of red fox as a predator of livestock and game species before planning management actions. In the analyzed farmland, for instance, a population-control program should not be justified despite the presence of lambs, piglets, hares and pheasants.  相似文献   
10.
Regional Environmental Change - This paper explores the relationship between specific household traits (region of residence, head of household occupation, financial diversity, female level of...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号