Long-term persistence of freshwater mussel beds in labile river channels
Long-term persistence of freshwater mussel beds in labile river channels
复制标题
不稳定河道中淡水贻贝床的长期存在
DOI：
10.1111/fwb.13175
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发表时间：
2018
影响因子：
2.7
通讯作者：
Vaughn, Caryn C.
中科院分区：
文献类型：
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作者：
Sansom, Brandon J.;Bennett, Sean J.;Atkinson, Joseph F.;Vaughn, Caryn C.
淡水贻贝是世界上最濒危的物种之一，人们花费了大量的努力来了解它们的急剧下降。目前的模式是，几十年来相对的河床稳定性对于维持给定河段的贻贝床位至关重要。然而，这些信息与对自然形成的河流的基本认识形成了鲜明的对比。在这里，我们研究了聚集淡水贻贝群落(贻贝床)的长期出现与它们所在的动态河流的关系。我们调查了两条河流中有历史记录的贻贝组合，以证明它们的长期持久性，并用二维水流和泥沙输送模型模拟了河床移动，以估计河道形成过程中的推移。我们发现，有证据表明，在这两条河流中，贻贝床在时间和种类上长期存在，并且贻贝床内显著的床面移动每隔1-2年发生一次。对于河床不稳定的自形成河流来说，这一点是可以预期的。我们的结果表明，贻贝已经适应了在河床上的繁殖，但还需要进一步的研究来理解贻贝群落长期存在的生物物理机制。
Freshwater mussels are among the world’s most imperilled species, and much effort has been expended to understand their precipitous decline. The current paradigm is that relative river bed stability over decades is critical to maintaining mussel beds at a given river reach. Such information, however, is in stark contrast to the fundamental understanding of self‐formed rivers.Here, we examine the relationship between long‐term occurrence of aggregated freshwater mussel communities (mussel beds) and the dynamic rivers in which they live.We surveyed mussel assemblages in two streams with historical records to document their long‐term persistence, and we simulated bed mobility with a two‐dimensional flow and sediment transport model to estimate bedload transport during channel‐forming discharges.We found evidence of long‐term mussel bed persistence, in time and in kind, within these two streams and that significant bed mobility within mussel beds occurs every 1–2 years, as to be expected for self‐formed rivers with labile beds. Flow refugia, or bed immobility, thus cannot completely explain the persistence of these mussel beds.Our results suggest that mussels have adapted to proliferate in river channels that often experience significant bed mobility, but further studies are needed to understand the biophysical mechanisms enabling the long‐term persistence of mussel communities.