A global 'greening' of coastal dunes: An integrated consequence of climate change?
A global 'greening' of coastal dunes: An integrated consequence of climate change?
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DOI：
10.1016/j.gloplacha.2019.103026
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发表时间：
2019-11-01
影响因子：
3.9
通讯作者：
Cooper, Andrew
中科院分区：
文献类型：
--
作者：
Jackson, Derek W. T.;Costas, Susana;Cooper, Andrew
在全球气候变化和海平面上升的背景下，沿海沙丘往往是沿海应对风暴波和风暴潮对沿海低地影响的重要因素。植被覆盖反过来又对沿海沙丘形态和风暴缓冲功能产生深远影响；它结合现有的沉积物，促进新鲜沉积物的积累，从而增加沙丘体积和沙丘顶高度，其中沉积物与植物的相互作用与植被生长试图超过垂直沉积物积累的速度有关。全球分析表明，1984年至2017年期间，各大洲多个地理分散的沿海沙丘场的植被覆盖率大幅增加。观察到的“绿化”表明沙丘稳定性和风暴缓冲效应增强，而矛盾的是，海岸因海平面上升和风暴模式变化而遭受更大的洪水和侵蚀风险。生物趋势对气候变化的因果归因很复杂，但我们认为，全球范围内沿海沙丘的“绿化”是由气候和大气成分变化共同驱动的，反映了温度、降水、营养物浓度变化和风度减少的累积效应（全球静止）。全球范围内温度、养分和降水的增加（所有这些都是植被生长的刺激物）和风的普遍减少（“静止”）（减少沉积物活动，促进植被的蔓延）与观察到的植被覆盖变化同时发生。观察到的沿海沙丘变化增强了当代和近期沿海对气候变化的适应能力，并可能代表了以前未被认识到的由气候变化介导的形态反馈。
In the context of global climate change and sea-level rise, coastal dunes are often important elements in the coastal response to storm wave and storm surge impacts on coastal lowlands. Vegetation cover, in turn, has profound impacts on coastal dune morphology and storm-buffering function; it binds existing sediment, promotes fresh sediment accumulation and thereby increases dune volume and dune crest elevation where a sediment-plant interaction plays out with vegetation growth attempting to out-pace the vertical sediment accumulation.A global analysis shows that vegetation cover has increased substantially on multiple, geographically dispersed, coastal dune fields on all continents in the period 1984-2017. The observed 'greening' points to enhanced dune stability and storm buffering effects at a time when, paradoxically, coasts are being subjected to increased flood and erosion risk from rising sea levels and changing patterns of storminess.Causal attribution of biological trends to climate change is complicated, but we contend that the global scale 'greening' of coastal dunes is driven by a combination of changes to climate and atmospheric composition and reflects the cumulative effects of changes in temperature, precipitation, nutrient concentration and reduced windiness (global stilling). Global-scale increases in temperature, nutrients and precipitation (all of which are vegetation growth stimulants) and widespread reduction in windiness ("stilling") (which reduces sediment activity, promoting the spread of vegetation) coincide in time with the observed changes in vegetation cover. The observed changes in coastal dunefields enhance contemporary and near-future coastal resilience to climate change and may represent a previously unrecognised morphological feedback mediated by climate change.