Newt decline in Western Europe: highlights from relative distribution changes within guilds
Newt decline in Western Europe: highlights from relative distribution changes within guilds
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DOI：
10.1007/s10531-012-0343-x
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发表时间：
2012-10-01
影响因子：
3.4
通讯作者：
Denoel, Mathieu
中科院分区：
文献类型：
--
作者：
Denoel, Mathieu
最近监测方案数量的增加为高质量的分布地图集奠定了基础。这为估计跨区域和国家边界的全球和具体下降模式提供了机会。在此框架下，本研究重点研究了西欧六个地理区域（五个国家）的四种同域蝾螈，包括大冠蝾螈（Triturus cristatus），一种附件2欧洲栖息地指令物种。这里使用的是跨时间的分布图的相对比较，它基于超过12000个已占用的网格单元。它受益于群落的定义，因为这些物种在湿地中可以同时检测到。在粗粒和细粒分辨率下，冠状蝾螈和高山蝾螈分别是受威胁最大和最小的蝾螈种，而掌状蝾螈和光滑蝾螈在粗粒和细粒分辨率下均有中等程度的下降。然而，欧洲各地的地区差异和规模效应也被发现。一方面，这些结果表明，在西欧，冠状瓢虫不仅受到区域威胁，而且受到全球衰退的影响。另一方面，研究结果表明，在欧洲，物种数量下降的模式并不统一，通常被认为是常见的、没有受到威胁的物种实际上比其他物种下降得更多。最后，提议的方法，即使用行会来评估相对下降，将有助于补充其他标准化方法，为保护管理人员和政策制定者提供正确的建议，特别是对那些下降幅度较小的物种。
The recent increase in the number of monitoring schemes has formed the basis for high quality distribution atlases. This provides the opportunity of estimating global and specific decline patterns across regional and national borders. In this framework, this study focused on four sympatric newt species-including the great crested newt (Triturus cristatus), an Annex 2 European Habitats Directive species, over six geographic areas (five countries) in Western Europe. A relative comparison of distribution maps across time is used here and is based on more than twelve thousands occupied grid cells. It benefits from the definition of a guild, as these species are simultaneously detectable in wetlands. T. cristatus and the alpine newt (Mesotriton alpestris) were the most and the least threatened newt species, respectively, whereas the palmate (Lissotriton helveticus) and smooth newt (Lissotriton vulgaris) had an intermediate decline level at both coarse and fine grain resolutions. However, regional variations across Europe and scale effects were also found. On one hand, these results show that T. cristatus is not only regionally threatened but suffers from a global decline in Western Europe. On another hand, the results indicate that patterns of decline are not uniform within Europe and that species often considered as common and not threatened are, in fact, declining more than others. Finally, the proposed methodology, i.e. using guilds to assess relative decline, would be useful as a complement to other standardized methods in correctly advising conservation managers and policy makers, particularly for species with more subtle declines.