Habitat factors affecting the distribution and abundance of spinous loach, Cobitis shikokuensis, in southwestern Japan
Habitat factors affecting the distribution and abundance of spinous loach, Cobitis shikokuensis, in southwestern Japan
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影响日本西南部刺泥鳅分布和丰度的生境因素
DOI：
10.1007/s10228-011-0208-4
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发表时间：
2011
影响因子：
1.2
通讯作者：
Shimizu T.
中科院分区：
文献类型：
--
作者：
Kawanishi R.;Inoue M.;Takagi M.;Miyake Y.;Shimizu T.
我们研究了日本西南部重信川水系中与刺泥鳅（Cobitis shikokuensis）（一种濒临灭绝的底栖鱼类）的分布和丰度相关的栖息地因素。在研究河流中，刺泥鳅沿着主干分布广泛，从源头到河口附近，而在支流中很少发现。分类树分析表明，刺泥鳅的存在/不存在可以通过卵石百分比和人工屏障之间河流碎片的长度来解释。在卵石丰富的地区，刺泥鳅发病率较高（>27.7%），但在河段短（≤0.97 km）的地区，即使卵石丰富，发病率也较低。泥鳅密度的回归树模型仅保留卵石百分比作为单个最佳预测因子，卵石百分比较高（> 40.4％）的地点具有较高的密度。这些结果表明，基质条件是决定刺泥鳅分布和丰度的重要因素，而且人工屏障造成的生境破碎化对该河中的刺泥鳅种群具有巨大的威胁潜力。考虑到研究河流高度分散的情况以及通过障碍阻止上游迁移，我们得出结论，维持上游适宜的栖息地对于刺泥鳅的保护具有高度优先权。
We examined habitat factors related to the distribution and abundance of the spinous loachCobitis shikokuensis, an endangered benthic fish, in the Shigenobu River system, southwestern Japan. In the study river, the spinous loach was distributed widely along the main stem, from headwater to near the mouth, whereas it was rarely found in tributary streams. Classification tree analysis showed that the presence/absence of spinous loach was explained by a combination of percent pebble and length of river fragment between artificial barriers. Spinous loach incidence was high in sites with abundant pebble (>27.7%), but low in sites with short river fragment (≤0.97 km) even if pebbles were abundant. A regression tree model for loach density retained only percent pebble as a single best predictor, with sites with higher percent pebble (>40.4%) having higher density. These results suggest that substrate condition is an important factor determining the distribution and abundance of spinous loach and also that habitat fragmentation by artificial barriers has great potential to threaten the spinous loach population in this river. Considering the highly fragmented situation of the study river and prevention of upstream migration by barriers, we conclude that maintenance of suitable habitats in upper reaches has high priority for conservation of the spinous loach.