Interactions between river flows and colonizing vegetation on a braided river: exploring spatial and temporal dynamics in riparian vegetation cover using satellite data
Interactions between river flows and colonizing vegetation on a braided river: exploring spatial and temporal dynamics in riparian vegetation cover using satellite data
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DOI：
10.1002/esp.2166
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发表时间：
2011-09-01
影响因子：
3.3
通讯作者：
Gurnell, A. M.
中科院分区：
文献类型：
--
作者：
Bertoldi, W.;Drake, N. A.;Gurnell, A. M.
现场，实验室和数值模拟研究越来越多地表明河岸树木的殖民化和增长的潜力，影响河流动力学和河流地貌的演变。本文联合分析了多时相，多光谱ASTER数据，连续河流水位和流量数据，以及沿着21 km的Taguzzento河，意大利河段的主要河岸树种（黑杨）的生长速率的实地观测。研究的重点是2004-2009年期间，在此期间，2004年10月24日发生了一次平滩洪水，随后两年水位较低，近两年只有适度的流量脉冲，然后是2008年8月15日的最后一个时期，其中包括几次中间到平滩流量事件。这一研究期间，增加流量扰动允许在不断变化的流量条件下，河流的活动走廊内的植被动态的探索。分析表明，利用ASTER数据调查植被动态沿着大河流廊道，并揭示了空间和时间的变化，在研究范围内的扩展，合并，和侵蚀的植被斑块。植被覆盖区的范围及其动态变化沿着研究河段。在河岸树木生长旺盛的子河段，植被面积在没有河道整形流量的时间段内迅速扩大，随后能够抵抗河岸洪水的侵蚀。相反，在树木生长不太旺盛的子河段，植被面积以较慢的速度扩大，更容易被漫滩洪水事件重置。这表明，河岸树木的生长速度是至关重要的，他们的能力，积极促进河流走廊动态。版权所有（c）2011约翰威利父子有限公司
Field, laboratory, and numerical modelling research are increasingly demonstrating the potential of riparian tree colonization and growth to influence fluvial dynamics and the evolution of fluvial landforms. This paper jointly analyses multi-temporal, multispectral ASTER data, continuous river stage and discharge data, and field observations of the growth rates of the dominant riparian tree species (Populus nigra) along a 21 km reach of the Tagliamento River, Italy. Research focuses on the period 2004-2009, during which there was a bankfull flood on 24 October 2004, followed by 2 years with low water levels, nearly 2 years with only modest flow pulses, and then a final period from 15 August 2008 that included several intermediate to bankfull flow events. This study period of increasing flow disturbance allows the exploration of vegetation dynamics within the river's active corridor under changing flow conditions. The analysis demonstrates the utility of ASTER data for investigating vegetation dynamics along large fluvial corridors and reveals both spatial and temporal variations in the expansion, coalescence, and erosion of vegetated patches within the study reach. Changes in the extent of the vegetated area and its dynamics vary along the study reach. In sub-reaches where riparian tree growth is vigorous, the vegetated area expands rapidly during time periods without channel-shaping flows, and is subsequently able to resist erosion by bankfull floods. In contrast, in sub-reaches where tree growth is less vigorous, the vegetated area expands at a slower rate and is more readily re-set by bankfull flood events. This illustrates that the rate of growth of riparian trees is crucial to their ability to contribute actively to river corridor dynamics. Copyright (c) 2011 John Wiley & Sons, Ltd.