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   51篇
  免费   1篇
大气科学   1篇
地球物理   6篇
地质学   6篇
海洋学   10篇
天文学   29篇
  2021年   1篇
  2018年   1篇
  2016年   4篇
  2015年   1篇
  2014年   2篇
  2013年   4篇
  2011年   1篇
  2009年   5篇
  2008年   3篇
  2007年   7篇
  2006年   2篇
  2005年   3篇
  2003年   2篇
  2002年   4篇
  2000年   1篇
  1998年   3篇
  1997年   2篇
  1996年   1篇
  1991年   1篇
  1987年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有52条查询结果,搜索用时 0 毫秒
51.
52.
Cuvier's beaked whale (Ziphius cavirostris, G. Cuvier 1823) is a poorly known species and many international agreements have asked for a better understanding of its biology for conservation purposes. In the present study, systematic cetacean surveys were carried out from ferries along a trans‐regional fixed transect in the Central Tyrrhenian Sea (Civitavecchia, Latium – Golfo Aranci, Sardinia), just outside the southeastern border of the Pelagos Sanctuary. This research provided long‐term, consistent data on Cuvier's beaked whale during two research periods (1990–1992 and 2007–2011). The objective of the research was to compare the presence, distribution and habitat use of Cuvier's beaked whale between the two investigated periods. Summer data (June–September) from the two periods were compared in terms of frequency of sightings, group size and spatial distribution related to the main ecogeographical features. A presence‐absence model (generalized additive modelling) was performed to predict habitat suitability in the two study periods. The results highlight long‐term site fidelity of Cuvier's beaked whale in the Central Tyrrhenian Sea with encounter rates comparable to the ones reported for other key areas. Separate suitability models based on 1990s and 2000s data appeared to work for each individual time period but differences were evident between the two periods, indicating changes in habitat selection over time. Our findings of the study appear to expand the definition of suitable beaked whale habitat and underline how the temporal scale of the analysis can affect the results in habitat studies. Moreover, this research highlights the importance of the Central Tyrrhenian Sea marine region for Cuvier's beaked whale and the ability of continuous monitoring to identify changes in cetacean frequency and distribution, necessary for adaptive conservation management approaches.  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