Dynamic patch mosaics and channel movement in an unconfined river valley of the Olympic Mountains
Dynamic patch mosaics and channel movement in an unconfined river valley of the Olympic Mountains
复制标题
奥林匹克山无限制河谷中的动态斑块马赛克和河道运动
DOI：
10.1111/j.1365-2427.2006.01513.x
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发表时间：
2006
影响因子：
2.7
通讯作者：
R. Naiman
中科院分区：
文献类型：
--
作者：
J. Latterell;J. Bechtold;T. C. O'Keefe;R. Pelt;R. Naiman
总结1。河谷就像动态的马赛克，由一块块自然的、短暂的陆地表面特征组成，这些特征是由河流的共同作用和多年到几个世纪的连续过程产生的。它们同时调节和反映河流能量的分布以及河岸和水生环境之间沉积物、木材和颗粒有机质的交换。2. 研究了美国华盛顿州奥林匹克山脉温带沿海森林中Queets河谷7种斑块类型的结构、组成、动态和起源。补丁类型包括：(1)主通道和(2)次通道；(3)先锋沙洲；（四）发展中的洪泛平原；（五）已形成的洪泛平原；(6)过渡型和(7)成熟型河流阶地。3. 横向通道运动强烈地塑造了斑块的分布、结构和动力学。从1939年到2002年，主要通道平均横向移动1300万年1，但在地点和时间上变化很大。整个流域的平均横向移动速率为1 ~ 59 m（年）1，移动平均（2 km）为3 ~ 28 m（年）1。4. 每个斑块类型都表现出特有的植被、土壤和大木材的积累。先锋棒材包含峰值茎密度（69 778茎公顷）1)和大木材体积（289米3公顷）1)。成熟河流阶地的平均茎干（1739 m 3 ha）和冠层体积（158 587 m 3 ha）最高。这些斑块还含有最多的土壤氮（537 kg hm2）和碳（5972 kg hm2）。5. 在森林斑块类型中，斑块半衰期（现有斑块一半被侵蚀所需的时间）从21年到401年不等。侵蚀率最高的是开拓沙洲（每年2.3%）和发展中的洪泛平原（每年3.3%），而成熟河流阶地的侵蚀率仅为每年0.17%。新的森林不断形成，作为先驱的植被在18年内占领了50%的水道系统，但往往不成功。6. 在Queets河中，斑块状河岸森林的结构、组成和动态取决于河道运动和大型木材、活植被和地貌过程之间的生物物理反馈之间的相互作用。斑块发展的循环使河谷内不断变化的栖息地马赛克得以延续，这些栖息地能够支持不同的生物组合。
SUMMARY 1. River valleys resemble dynamic mosaics, composed of patches which are natural, transient features of the land surface produced by the joint action of a river and successional processes over years to centuries. They simultaneously regulate and reflect the distribution of stream energy and exchanges of sediment, wood and particulate organic matter between riparian and aquatic environments. 2. We determined the structure, composition, dynamics and origin of seven patch types at the reach scale in the Queets River valley in the temperate coastal forests of the Olympic Mountains, Washington (U.S.A.). Patch types included: (1) primary and (2) secondary channels; (3) pioneer bars; (4) developing and (5) established floodplains; and (6) transitional and (7) mature fluvial terraces. 3. Lateral channel movements strongly shape patch distribution, structure and dynamics. The primary channel moved laterally 13 m year )1 , on average from 1939 to 2002, but was highly variable among locations and over time. Mean lateral movement rates ranged from 1 to 59 m year )1 and moving averages (2 km) ranged from 3 to 28 m year )1 throughout the valley. 4. Each patch type exhibited characteristic vegetation, soil and accumulations of large wood. Pioneer bars contained peak stem density (69 778 stems ha )1 ) and volume of large wood (289 m 3 ha )1 ). Mature fluvial terraces contained the highest mean stem (1739 m 3 ha )1 ) and canopy volume (158 587 m 3 ha )1 ). These patches also contained the most soil nitrogen (537 kg ha )1 ) and carbon (5972 kg ha )1 ). 5. Patch half-life (the time required for half of the existing patches to be eroded) ranged from 21 to 401 years among forested patch types. Erosion rates were highest in pioneer bars (2.3% year )1 ) and developing floodplains (3.3% year )1 ), compared with only 0.17% year )1 in mature fluvial terraces. New forests formed continually, as pioneering vegetation colonised 50% of the channel system within 18 years, often unsuccessfully. 6. In the Queets River, the structure, composition, and dynamics of the patchy riparian forest depends on the interplay between channel movements and biophysical feedbacks between large wood, living vegetation and geomorphic processes. The cycle of patch development perpetuates a shifting-mosaic of habitats within the river valley capable of supporting diverse biotic assemblages.