Overlap in spawning habitat characteristics between two salmonids in relation to stream size: redd superimposition hypothesis on longitudinal species replacement
Overlap in spawning habitat characteristics between two salmonids in relation to stream size: redd superimposition hypothesis on longitudinal species replacement
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DOI：
10.1139/cjfas-2022-0237
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发表时间：
2023-02-15
影响因子：
2.4
通讯作者：
Inoue，Mikio
中科院分区：
文献类型：
--
作者：
Togaki，Daisuke;Sunohara，Ayaka;Inoue，Mikio
Redd的叠加，产卵前产卵的redd后产卵，减少了前产卵的繁殖成功。因此，在redd叠加频繁发生的溪流中，晚产卵的物种比早产卵的物种具有竞争优势。我们假设，较小的渠道上游将有更高的潜力redd叠加由于较低的可用性产卵栖息地，从而提供了一个竞争优势，晚产卵的物种，以解释位移的本地masu鲑鱼（Oncorhynchus masou ishikawae）的非本地的白斑红点鲑（Salvelinus leucomaenis）（晚产卵）特定的小上游在日本的河流。我们研究了（1）产卵栖息地的可用性和（2）产卵栖息地的重叠特征之间的两个物种在不同的通道大小的流。结果表明：（1）随着河道面积的减小，上游的栖息地可利用性降低;（2）在小河道中，两种鱼类的产卵栖息地特征高度重叠，而在大河道中，两种鱼类的产卵栖息地特征差异显著，支持了我们的假设。我们的研究结果提供了一个新的视角在鲑鱼的竞争优势的纵向变化。
Redd superimposition, spawning on a previous spawner's redd by a later spawner, reduces reproductive success of the previous spawner. Therefore, in streams where redd superimposition frequently occurs, late-spawning species have a competitive advantage over early-spawning species. We hypothesised that smaller channels of upper reaches would have higher potential of redd superimposition owing to lower availability of spawning habitat, thereby providing a competitive advantage to late-spawning species, to explain a displacement of native masu salmon (Oncorhynchus masou ishikawae) by non-native white-spotted char (Salvelinus leucomaenis) (late spawner) specific to small upper reaches in a Japanese river. We examined (1) the availability of spawning habitat and (2) overlap in spawning habitat characteristics between the two species in streams with different channel size. The results showed that (1) the habitat availability decreased upstream as channel size decreased, and (2) characteristics of spawning habitat highly overlapped between the two species in small channels, whereas those differed significantly between the two species in larger channels, supporting our hypothesis. Our results provide a new perspective on longitudinal changes in competitive advantages in salmonids.