Hydrologic, geomorphic and climatic processes controlling willow establishment in a montane ecosystem
Hydrologic, geomorphic and climatic processes controlling willow establishment in a montane ecosystem
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控制山地生态系统中柳树生长的水文、地貌和气候过程
DOI：
10.1002/hyp.5965
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发表时间：
2006
影响因子：
3.2
通讯作者：
L. Landrum
中科院分区：
文献类型：
--
作者：
D. Cooper;Joyce R. Dickens;N. Hobbs;L. Christensen;L. Landrum
杨柳群落在北美落基山脉的中海拔河岸地区占主导地位。然而，许多杨柳林分的空中覆盖率和个体植物的高度正在迅速下降。对控制杨柳建立的过程了解不多，阻碍了确定这种衰退的原因。我们分析了促进或限制杨柳建立在20世纪后半叶在科罗拉多州落基山国家公园的两个大洪泛区的过程，解决两个问题：（1）水文制度如何控制杨柳建立在不同的河流地貌？(2)气候驱动的水文状况变化可能如何影响未来的杨柳种植？我们精确地年龄柳树上的三个最常见的河流地貌，流点酒吧，排水海狸池塘，和废弃的渠道，并统计相关的成立日期的模式，每年的流峰值流量。洪峰流量对杨柳建植的作用因地形而异。杨柳的招募几乎每年都发生在点酒吧。在以前的海狸复合体，大多数柳树已建立以下大坝决口，而柳树已建立在废弃的渠道几年后，渠道撕脱。点坝和废弃河道上的设施是由2至5年重现期的峰值流量驱动的，而在废弃的海狸池塘中，大多数设施与>5年重现期的流量事件相关。气候变化模型表明，在未来几十年里，落基山脉的气温将上升，降水季节性将发生变化，导致春季径流提前，夏季和秋季流量减少，积雪减少，土壤湿度下降。这些变化可能会减少杨柳建立的机会。版权所有© 2005年约翰威利父子有限公司。
Willow communities dominate mid‐elevation riparian areas throughout the Rocky Mountains of North America. However, many willow stands are rapidly declining in aerial cover and individual plants in stature. A poor understanding of the processes that control willow establishment hinders identifying the causes of this decline. We analysed the processes that have facilitated or limited willow establishment over the last half of the 20th century on two large floodplains in Rocky Mountain National Park in Colorado by addressing two questions: (1) How does hydrologic regime control willow establishment on different fluvial landforms? (2) How might climate‐driven variations in hydrologic regime affect future willow establishment? We precisely aged willows on the three most common fluvial landforms, stream point bars, drained beaver ponds, and abandoned channels, and statistically related establishment dates to patterns of annual stream peak flow. The role of peak flow on willow establishment varied significantly by landform. Willow recruitment had occurred nearly every year on point bars. In former beaver complexes, most willows had established following dam breaches, whereas willows had established on abandoned channels for several years following channel avulsion. Establishment on point bars and abandoned channels was driven by peak flows of 2‐ to 5‐year return intervals, whereas in abandoned beaver ponds most establishment was associated with flow events of >5‐year return interval. Models of climate change suggest that temperatures will increase and precipitation seasonality will shift over the coming decades in the Rocky Mountains, leading to earlier spring runoff, lower summer and fall flows, decreased snowpack and decreased soil moisture. Such changes are likely to diminish opportunities for willow establishment. Copyright © 2005 John Wiley & Sons, Ltd.