The pervasive and multifaceted influence of biocrusts on water in the world's drylands
The pervasive and multifaceted influence of biocrusts on water in the world's drylands
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DOI：
10.1111/gcb.15232
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发表时间：
2020-07-30
影响因子：
11.6
通讯作者：
Zhao, Yunge
中科院分区：
文献类型：
--
作者：
Eldridge, David J.;Reed, Sasha;Zhao, Yunge
水的捕获和利用在旱地至关重要，旱地共同构成了地球上最大的生物群。随着下个世纪气候条件的变化，旱地可能会经历更少、更不可靠的降雨量。旱地土壤支持着丰富的微生物群落(生物壳)，这是至关重要的，因为它们调节着水分的输送和保持。然而，尽管它们具有重要的水文学意义，但缺乏它们对水文学影响的全球综合。我们综合了来自109个出版物的2,997个观察结果，以探索生物结壳如何影响五个水文过程(蓄水和径流的时间，进入土壤的水的早期[吸附]和最后[渗透]阶段，以及径流的速度或体积)和两个水文结果(水分储存和泥沙产生)。我们发现，增加生物灰土盖度减少了水在地表池塘的时间(-40%)和开始径流的时间(-33%)，减少了入渗(-34%)和产沙量(-68%)。较大的生物量覆盖对土壤吸水率和径流速率/流量没有显著影响，但增加了贮水量(+14%)。细尺度土壤入渗量下降最多(-56%)，大尺度土壤贮水量最大(+36%)。生物尘埃类型(蓝藻、地衣、苔藓、混合)、土壤质地(沙、壤土、粘土)和气候带(干旱、半干旱、干燥亚湿润)的影响有细微差别。我们的合成为旱地生物灰尘效应的大小、过程和背景提供了新的见解。随着地球变得越来越热和越来越干燥，这些信息对于提高我们管理日益减少的旱地水资源供应的能力至关重要。
The capture and use of water are critically important in drylands, which collectively constitute Earth's largest biome. Drylands will likely experience lower and more unreliable rainfall as climatic conditions change over the next century. Dryland soils support a rich community of microphytic organisms (biocrusts), which are critically important because they regulate the delivery and retention of water. Yet despite their hydrological significance, a global synthesis of their effects on hydrology is lacking. We synthesized 2,997 observations from 109 publications to explore how biocrusts affected five hydrological processes (times to ponding and runoff, early [sorptivity] and final [infiltration] stages of water flow into soil, and the rate or volume of runoff) and two hydrological outcomes (moisture storage, sediment production). We found that increasing biocrust cover reduced the time for water to pond on the surface (-40%) and commence runoff (-33%), and reduced infiltration (-34%) and sediment production (-68%). Greater biocrust cover had no significant effect on sorptivity or runoff rate/amount, but increased moisture storage (+14%). Infiltration declined most (-56%) at fine scales, and moisture storage was greatest (+36%) at large scales. Effects of biocrust type (cyanobacteria, lichen, moss, mixed), soil texture (sand, loam, clay), and climatic zone (arid, semiarid, dry subhumid) were nuanced. Our synthesis provides novel insights into the magnitude, processes, and contexts of biocrust effects in drylands. This information is critical to improve our capacity to manage dwindling dryland water supplies as Earth becomes hotter and drier.