Riparian vegetation loss, stream channelization, and web-weaving spiders in northern Japan
Riparian vegetation loss, stream channelization, and web-weaving spiders in northern Japan
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DOI：
10.1007/s11284-005-0084-3
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发表时间：
2005-11-01
影响因子：
2
通讯作者：
Fausch, KD
中科院分区：
文献类型：
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作者：
Laeser, SR;Baxter, CV;Fausch, KD
河岸植被的移除和河道的矫直（河道化）是河流及其河岸地带最普遍的生境退化形式。两者都对栖息地的生物产生直接影响，但也有可能通过中断两个相邻生态系统之间无脊椎动物猎物的流动而造成间接影响。我们在日本北海道的四种河流中测量了造网的河岸蜘蛛的丰度：相对未受干扰的河流，河岸植被被移除的河流，河岸重新生长的河道，以及既被河道化又被植被移除的河流。单生境干扰或双生境干扰均使蜘蛛丰度降低70%以上，蜘蛛科数量减少。蛛科的蜘蛛专门捕捉从溪流中爬出来的成虫，它们的数量由于栖息地的退化或两者的共同作用而大大减少。相比之下，在其他既捕获陆生也捕获水生猎物的蛛科中，植被的减少比渠道化更严重。这些结果表明，河岸植被的丧失通过减少蜘蛛的栖息地而对蜘蛛产生了强烈的直接影响。他们还认为，河道化可能通过减少从溪流到河岸地带的成年水生昆虫的流量，对河岸专家四鳃蜘蛛产生强烈的间接影响。
Removal of riparian vegetation and straightening of stream channels (channelization) are the most prevalent forms of habitat degradation in streams and their riparian zones. Both have direct effects on organisms in the habitats where they occur, but also have potential to cause indirect effects by interrupting the flux of invertebrate prey between the two adjacent ecosystems. We measured abundance of web-building riparian spiders along four types of streams in Hokkaido, Japan: relatively undisturbed streams, streams where riparian vegetation had been removed, previously channelized streams where the banks had revegetated, and streams that had been both channelized and had the vegetation removed. Spider abundance was reduced by 70% or more by either habitat disturbance alone, or both combined, and the number of spider families was also reduced. Spiders of the family Tetragnathidae, which specialize in capturing adult insects emerging from streams, were strongly reduced by either form of habitat degradation alone, or in combination. In contrast, abundance of spiders in other families that capture prey from both terrestrial and aquatic sources was reduced more strongly by vegetation loss than channelization. These results indicate that riparian vegetation loss has strong direct effects on spiders by reducing habitat for web sites. They also suggest that channelization can have strong indirect effects on riparian-specialist tetragnathid spiders, probably by reducing the flux of adult aquatic insects from the stream to the riparian zone.