Georges Anita, Fouillet Philippe, Pétillon Julien
U.M.R. 6553 - ''Ecosystèmes, Biodiversité, Evolution'', Université de Rennes 1, 263 Avenue du Gal Leclerc, CS74205, 35042 Rennes Cedex, France.
Zookeys. 2011(100):407-19. doi: 10.3897/zookeys.100.1537. Epub 2011 May 20.
As a result of an invasion by the native grass Elymus athericus (Link) Kerguélen (Poaceae) in the last 10 years, a major change in vegetation cover has occurred in salt marshes of the Mont Saint-Michel bay, Western France. The impact of such an invasion on carabid assemblages, a dominant group of terrestrial arthropods in these habitats and containing several stenotopic species, is investigated here. In our study site, carabid data are available from 1983 and 1984, allowing a comparison of species distribution ranges in salt marshes before (1983-1984) and after (2002) the Elymus athericus invasion. A total of 16,867 adults belonging to 40 species were caught. By considering the presence-absence of species shared between studies, we show that the invasion by Elymus athericus promoted the progression of non-coastal species (mainly Pterostichus s.l. spp.). This did however not interfere with resident species distributions, finally resulting in higher carabid species richness in the entire area. The species composition and abundances of carabid assemblages were also compared between natural and invaded stations in 2002. The main result is that abundances of some halophilic species decreased in one invaded plot (in case of Pogonus chalceus (Marsham 1802)) whereas the opposite pattern was observed for other species (e.g., Bembidion minimum (Fabricius 1792)). Invaded habitats were characterized by lower percentages of halophilic species and higher total species richness.
在过去十年中，由于当地禾本科植物滨麦（Elymus athericus (Link) Kerguélen）的入侵，法国西部圣米歇尔湾盐沼的植被覆盖发生了重大变化。本文研究了这种入侵对步甲类群（这些栖息地中陆地节肢动物的优势类群，包含多个狭域物种）的影响。在我们的研究地点，有1983年和1984年的步甲数据，这使得我们能够比较滨麦入侵之前（1983 - 1984年）和之后（2002年）盐沼中物种分布范围。总共捕获了属于40个物种的16,867只成虫。通过考虑不同研究中共享物种的存在与否，我们发现滨麦的入侵促进了非沿海物种（主要是广肩步甲属（Pterostichus s.l.）的物种）的扩散。然而，这并未干扰本地物种的分布，最终导致整个区域的步甲物种丰富度更高。2002年，我们还比较了自然站点和入侵站点的步甲类群的物种组成和丰度。主要结果是，在一个入侵地块中，一些嗜盐物种的丰度下降（例如铜绿广肩步甲（Pogonus chalceus (Marsham 1802)）），而其他物种（如微小斑步甲（Bembidion minimum (Fabricius 1792)））则呈现相反的模式。入侵栖息地的特征是嗜盐物种的比例较低，而总物种丰富度较高。
