Historical changes in the distribution and functions of large wood in Puget Lowland rivers
Historical changes in the distribution and functions of large wood in Puget Lowland rivers
复制标题
普吉特低地河流中大型木材分布和功能的历史变化
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
A. Haas
中科院分区：
文献类型：
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作者：
B. Collins;D. Montgomery;A. Haas
我们研究了从过去150年的土地利用的木材丰度和功能的变化，在普吉特低地河流从一个11公里长的保护范围内的Nisqually河与Snohomish和Stillaguamish河的实地数据和档案数据从几个普吉特低地河流的比较实地数据。目前的木材丰度比欧洲人在斯诺霍米什和斯蒂尔瓜米什盆地定居之前少了一到两个数量级。最重要的是，木材堵塞现在很少见，因为缺乏非常大的木材，可以作为关键件和木材补充率低。木材丰度和大小的这些变化似乎已经从根本上改变了形态，动态，和栖息地的丰富性和特点的低地河流跨越尺度从通道单元到谷底。根据我们的实地研究，历史上河流有更多更深的水池。档案数据和实地研究表明，木堵塞是不可或缺的创造和维持一个动态的，不断变化的河流格局与众多的洪泛平原渠道和丰富的边缘栖息地和路由洪水和沉积物到洪泛平原。建立欧洲人定居前的河流景观条件，为评估当代条件和制定恢复目标提供了参考。
We examined changes in wood abundance and functions in Puget Lowland rivers from the last ~150 years of land use by comparing field data from an 11-km-long protected reach of the Nisqually River with field data from the Snohomish and Stillaguamish rivers and with archival data from several Puget Lowland rivers. Current wood abundance is one to two orders of magnitude less than before European settlement in the Snohomish and Stillaguamish basins. Most importantly, wood jams are now rare because of a lack of very large wood that can function as key pieces and low rates of wood recruitment. These changes in wood abundance and size appear to have fundamentally changed the morphology, dynamics, and habitat abundance and characteristics of lowland rivers across scales from channel unit to valley bottom. Based on our field studies, rivers had substantially more and deeper pools historically. Archival data and field studies indicate that wood jams were integral to creating and maintaining a dynamic, anastomosing river pattern with numerous floodplain channels and abundant edge habitat and routed floodwaters and sediment onto floodplains. Establishing the condition of the riverine landscape before European settlement sets a reference against which to evaluate contemporary conditions and develop restoration objectives.