Vegetation cover dynamics along two Himalayan rivers: Drivers and implications of change.
Vegetation cover dynamics along two Himalayan rivers: Drivers and implications of change.
复制标题
两条喜马拉雅河流域的植被覆盖动态：变化的驱动因素和影响。
DOI：
10.1016/j.scitotenv.2022.157826
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Beale J
中科院分区：
文献类型：
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作者：
Beale J
河流是动态的景观特征，通过水文、地貌和生态过程响应自然和人为因素而变化。在过去的一个世纪里，人类对河流系统和河岸植被的影响的严重程度和程度急剧增加，这是由于跨越山谷的水坝的激增、农业的集约化、城市化和更广泛的渠道工程。本研究旨在确定这些人为改变所引起的地貌形态和动态变化与下游比斯河和萨特莱吉河河道和河岸植被的变化之间的关系。这些河流是印度河的支流，流经西喜马拉雅山脉，但近几十年来地貌变化的类型和程度不同。对30多年来的冬季植被进行了分析，揭示了两条河流流域植被覆盖的增加趋势，与大规模变化驱动因素相一致。活跃河道内更大的趋势表明，上游驱动因素正在影响河流流量、地貌、植被生长和人类开发。不同河流之间植被变化的空间格局不同，强调了上游人类活动（水坝和抽象）如何在河流景观背景下控制地貌和植被群落的响应。植被面积的增加强化了河面从宽辫状徘徊到单线徘徊的局部演化轨迹。活跃渠道的缩小正在改变资源供应和人们面临的风险之间的平衡。正在开发用于农业的新地区面临着河流侵蚀、洪水和沉积物沉积的更大风险。此外，从辫状地到蜿蜒地的变化集中了河岸的侵蚀，使社区和基础设施处于危险之中。通过量化和评估这些河流周围植被覆盖的空间变化，我们可以更好地了解植被和地貌的相互作用，以及人类活动和气候变化对这些河流以及许多类似的大型系统的影响，从而为可持续发展提供信息。
Rivers are dynamic landscape features that change in response to natural and anthropogenic factors through hydrological, geomorphic and ecological processes. The severity and magnitude of human impacts on river system and riparian vegetation has dramatically increased over the last century with the proliferation of valley-spanning dams, intensification of agriculture, urbanization, and more widespread channel engineering. This study aims to determine how changes in geomorphic form and dynamics caused by these human alterations relate to changes in channels and riparian vegetation in the lower Beas and Sutlej Rivers. These rivers are tributaries of the Indus that drain the Western Himalayas but differ in the type and magnitude of geomorphic change in recent decades. Winter season vegetation was analysed over 30 years, revealing increasing trends in vegetated land cover in the valleys of both rivers, consistent with large-scale drivers of change. Greater trends within the active channels indicate upstream drivers are influencing river flow and geomorphology, vegetation growth and human exploitation. The spatial patterns of vegetation change differ between the rivers, emphasizing how upstream human activities (dams and abstraction) control geomorphic and vegetation community response within the landscape context of the river. The increasing area of vegetated land is reinforcing the local evolutionary trajectory of the river planform from wide-braided wandering to single thread meandering. Narrowing of the active channels is altering the balance of resource provision and risk exposure to people. New areas being exploited for agriculture are exposed to greater risk from river erosion, inundation, and sediment deposition. Moreover, the change from braided to meandering planform has concentrated erosion on riverbanks, placing communities and infrastructure at risk. By quantifying and evaluating the spatial variations in vegetation cover around these rivers, we can better understand the interaction of vegetation and geomorphology alongside the impacts of human activity and climate change in these, and many similar, large systems, which can inform sustainable development.