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首页> 外文会议>AWRA's 2000 Summer Specialty Conference on Riparian Ecology and Management in Multi-Land USE Watersheds Aug 28-31, 2000 Portland, Oregon >SPAWNING GRAVEL FINE SEDIMENT LEVELS BETWEEN SEASONS AND LAND TYPE ASSOCIATIONS
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SPAWNING GRAVEL FINE SEDIMENT LEVELS BETWEEN SEASONS AND LAND TYPE ASSOCIATIONS

机译：季节和土地类型协会之间的粗碎细沙沉积水平

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摘要

Eighty-two stream reaches were sampled throughout the Monongahela National Forest during the summer 1996 and winter of 1996-1997 to quantify fine sediment levels (< 4 mm diameter material) in trout spawning gravels, examine seasonal differences in fine sediment, and determine if fine sediment levels differ among land type association (LTA), streambed slope classes and soil erosion potentials. Six shovel samples per stream reach were collected. Summer fine sediment levels (x =15.8%) were significantly greater than winter levels (x = 13.3%), meaning summer values cannot be used directly as measures of winter conditions. However, the lower winter values indicate conditions during spawning and egg development were actually better than summer data would have suggested. Fine sediment did not vary significantly among slope or erosion potential classes, but it did vary significantly among LTAs. Groupings of LTAs were identified which had low-, mid- and high-range fine sediment levels. Two of the three LTAs with highest sediment levels are high elevation areas with red spruce (Picea rubens) that have recovered poorly since 1890-1920 logging and/or subsequent heavy fires. Many streams in these two LTAs are acidic and have low nutrients, which also limit spawning and general fisheries success. Geology, specifically resistant sandstone, is believed to be a dominant factor in limiting sediment availability in LTAs with the lowest fine sediment levels.
机译：在1996年夏季和1996-1997年冬季，在整个Monongahela国家森林中采样了82条河流，以量化鳟鱼产卵砾石中的细沙水平（直径小于4毫米的物质），检查细沙的季节性差异，并确定是否细密。土地类型协会（LTA），河床边坡类别和土壤侵蚀潜力之间的沉积物含量有所不同。每个溪流采集六个铲子样品。夏季的细沙水平（x = 15.8％）大大高于冬季的水平（x = 13.3％），这意味着夏季值不能直接用作冬季条件的度量。但是，较低的冬季值表明产卵期间的条件和卵的发育实际上比夏季的数据要好。精细沉积物在坡度或侵蚀潜力类别之间变化不大，但在长期协议之间却存在显着变化。确定了具有低，中和高范围精细沉积物水平的长期协议的分组。沉积物含量最高的三个LTA中有两个是高海拔地区，带有红色云杉（Picea rubens），自1890-1920年伐木和/或随后发生大火以来恢复不佳。这两个长期协议中的许多溪流都是酸性的，营养成分低，这也限制了产卵和一般渔业的成功。人们认为，地质（特别是耐砂岩）是限制最低沉积物中最低沉积物含量的长期协议中沉积物可利用性的主要因素。

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