Holocene and Recent Geomorphic Processes, Land Use, and Salmonid Habitat in two North Puget Sound River Basins
Holocene and Recent Geomorphic Processes, Land Use, and Salmonid Habitat in two North Puget Sound River Basins
复制标题
两个北普吉特海湾盆地的全新世和近期地貌过程、土地利用和鲑鱼栖息地
DOI：
10.1029/ws004p0037
复制
发表时间：
2013
期刊：
影响因子：
3.9
通讯作者：
G. Pess
中科院分区：
文献类型：
--
作者：
T. Beechie;B. Collins;G. Pess
在过去的16,000年里，随着冰川后景观的演变和火山活动，以及最近的土地利用历史（约150年），斯卡吉特河和斯蒂尔瓜米什河流域鲑鱼栖息地的数量、质量和分布发生了巨大变化。大约16，000年前，科迪勒拉冰盖消退后，溪流迅速切入山谷填充冰川沉积物，降低谷底并形成阶地。主干和漫滩泥沼谷底提供了大部分的栖息地，但中度梯度的支流梯田提供了额外的栖息地，一些鲑鱼。基岩地形中的水道过于陡峭，无法支持溯河产卵的鲑鱼，直到今天仍然如此。大约5,500年前，冰川峰的大量泥流在斯卡吉特河上形成了一个广泛的低梯度三角洲，然后在湿地和分流河道中形成了丰富的栖息地。由于非美洲原住民定居者在19世纪中期到达，河狸池塘的拆除，堤防，沟渠和河漫滩和三角洲上的溪流疏浚已经隔离或消灭了两个盆地中大约50%的银鲑冬季饲养栖息地。这些损失主要与农业实践有关，农业实践占据了与大多数历史上的银鲑栖息地相同的地貌。林业活动集中在冰川沉积物和基岩地形的陡坡上，增加了沉积物供应，减少了木材丰富度，从而造成生境丧失。了解全新世景观演变，地貌过程，土地利用和鲑鱼栖息地的相互作用提供了一个背景下，制定栖息地恢复计划。
The quantity, quality, and distribution of salmonid habitats in the Skagit and Stillaguamish River basins have changed dramatically in response to post-glacial landscape evolution and volcanism over the last 16,000 years, and the more recent history of land use (approximately 150 years). After retreat of the Cordilleran ice sheet about 16,000 years ago, streams incised rapidly into valley-filling glacial sediments, lowering valley floors and creating terraces. Mainstems and floodplain sloughs on valley floors provided the majority of habitat, but moderate-gradient tributaries on terraces provided additional habitat for some salmonids. Channels in bedrock terrain were too steep to support anadromous salmonids and remain so today. Voluminous lahars from Glacier Peak approximately 5,500 years before present created an extensive low-gradient delta on the Skagit River, which then developed abundant habitats in wetlands and distributary channels. Since non-Native American settlers arrived in the mid-1800s, removal of beaver ponds, diking, ditching, and dredging of streams on the floodplains and deltas has isolated or obliterated approximately 50% of the coho salmon winter rearing habitat in both basins. These losses are associated mainly with agricultural practices, which occupy the same landforms as the majority of historical coho salmon habitat. Forestry activities are concentrated on the steeper slopes of the glacial sediments and bedrock terrain, and contribute to habitat losses by increasing sediment supplies and reducing wood abundance. Understanding the interplay of Holocene landscape evolution, geomorphic processes, land use, and salmonid habitat provides a context for developing habitat restoration programs.