Seawall as salmon habitat: Eco-engineering improves the distribution and foraging of juvenile Pacific salmon
Seawall as salmon habitat: Eco-engineering improves the distribution and foraging of juvenile Pacific salmon
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海堤作为鲑鱼栖息地：生态工程改善了幼年太平洋鲑鱼的分布和觅食
DOI：
10.1016/j.ecoleng.2020.105856
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发表时间：
2020
影响因子：
3.8
通讯作者：
Jeffery R. Cordell
中科院分区：
文献类型：
--
作者：
Alexandra C. Sawyer;J. Toft;Jeffery R. Cordell
城市近岸生态系统是一种建筑环境，其结构和功能与它们所取代的自然生态系统不同。生态工程提供了通过减少海岸线改造的影响来加强这些生态系统的能力。最近的研究表明，海岸线铠装和码头阴影修改海岸线的共同特点，以降低觅食率，改变分布模式，并增加捕食风险的少年鲑鱼。2017年，美国华盛顿州西雅图埃利奥特湾海堤的更换采用了新颖的生态工程设计元素，包括水上结构中的玻璃透光表面（LPS）、高架海底和海堤表面的纹理基材，以改善幼太平洋鲑鱼（Oncorhynchusspp.）的近岸栖息地。从出生河流迁移到海洋。为了研究海堤生态工程的有效性，我们使用通气管调查，以评估幼鲑的空间分布和觅食模式的变化，在高峰期（3月至8月），并测量环境光穿透之前和之后的海堤更换。总的来说，我们发现，幼鲑分布更均匀的空间马赛克的栖息地生态工程后。LPS增强了环境光穿透在近岸码头下的栖息地，幼鲑利用这些栖息地同时增加。码头下的鲑鱼密度往往是最大的低潮，表明光的可用性可能介导的选择性栖息地的使用。喂食率在紧邻海堤的网站增加之间和码头下的栖息地改善。我们的研究结果表明，由LPS促进的光照水平升高，与提供更复杂的浅水栖息地的物理增强相一致，缓和了码头阴影和海岸线铠装对幼鲑的负面影响。
Urban nearshore ecosystems are built environments that differ structurally and functionally from the natural ecosystems they replace. Eco-engineering offers the ability to enhance these ecosystems by reducing the impacts of shoreline modification. Recent studies have linked shoreline armoring and pier shade—common features of modified shorelines—to lower foraging rates, altered distribution patterns, and increased predation risk for juvenile salmon. The 2017 replacement of the Elliott Bay seawall in Seattle, WA, USA incorporated novel eco-engineering design elements, including glass light penetrating surfaces (LPS) in overwater structures, an elevated seafloor, and textured substrates in the seawall face to enhance nearshore habitat for juvenile Pacific salmon (Oncorhynchusspp.) migrating from natal streams to the ocean. To examine the effectiveness of seawall eco-engineering, we used snorkel surveys to assess changes in juvenile salmon spatial distribution and foraging patterns during peak outmigration (March–August), and measured ambient light penetration before and after seawall replacement. Overall, we found that juvenile salmon were distributed more evenly across a spatial mosaic of habitats following eco-engineering. LPS enhanced ambient light penetration in nearshore under-pier habitats, and juvenile salmon use of these habitats increased concurrently. Salmon densities under piers tended to be greatest at low tides, indicating that light availability may mediate selective habitat use. Feeding rates at sites immediately adjacent to the seawall increased both between and under piers following habitat enhancement. Our findings suggest that the elevated light levels facilitated by LPS, in concert with physical enhancements that provided more complex shallow water habitat, temper the negative effects of pier shade and shoreline armoring on juvenile salmon.