Vascular Plants and Biocrusts Modulate How Abiotic Factors Affect Wetting and Drying Events in Drylands
Vascular Plants and Biocrusts Modulate How Abiotic Factors Affect Wetting and Drying Events in Drylands
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DOI：
10.1007/s10021-014-9790-4
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发表时间：
2014-11-01
期刊：
影响因子：
3.7
通讯作者：
Maestre, Fernando T.
中科院分区：
文献类型：
--
作者：
Berdugo, Miguel;Soliveres, Santiago;Maestre, Fernando T.
了解生物体如何控制土壤水动态是旱地生态学的一个主要研究目标。尽管以前的研究主要集中在维管束植物对旱地水文循环的作用，但最近的研究强调了由地衣、苔藓和蓝藻（生物结皮）形成的生物土壤结皮作为该循环中主要参与者的重要性。我们使用了一项为期 6.5 年的研究数据来评估多种非生物（降雨特征、温度和初始土壤湿度）和生物（维管植物和生物结皮）因素如何相互作用，从而确定西班牙中部半干旱草原的湿润和干燥过程。我们发现，与裸地区域 (BSCl) 相比，中等覆盖 (25-75%) 的灌木 Retama sphaerocarpa 和生物结皮增强了水分增益并减缓了干燥。发育良好的生物结皮（> 75% 覆盖率）获得了更多的水分，但比 BSCl 微站点失去的速度更快。与 BSCl 微站点相比，草针茅因降雨拦截而减少了水增益，但增加了土壤保水性。水动力学的生物调节是不同机制协同作用且通常方向相反的结果。例如，生物结皮在干燥曲线的第一阶段促进了指数行为，但降低了加剧干燥速率的土壤特征的重要性。以生物结皮为主的微场所获得的水量与维管植物相似，尽管它们在干旱时期比维管植物失去水分更快。我们的结果强调了生物结皮对于旱地水动力学的重要性，并说明了其影响背后的潜在机制。它们将有助于进一步推进有关旱地水文及其对持续气候变化的响应的理论和建模工作。
Understanding how organisms control soil water dynamics is a major research goal in dryland ecology. Although previous studies have mostly focused on the role of vascular plants on the hydrological cycle of drylands, recent studies highlight the importance of biological soil crusts formed by lichens, mosses, and cyanobacteria (biocrusts) as a major player in this cycle. Weused data froma 6.5-year study to evaluate how multiple abiotic (rainfall characteristics, temperature, and initial soil moisture) and biotic (vascular plants and biocrusts) factors interact to determine wetting and drying processes in a semi-arid grassland from Central Spain. We found that the shrub Retama sphaerocarpa and biocrusts with medium cover (25-75%) enhanced water gain and slowed drying comparedwith bare ground areas (BSCl). Well-developed biocrusts (> 75% cover) gained more water, but lost it faster than BSCl microsites. The grass Stipa tenacissima reduced water gain due to rainfall interception, but increased soil moisture retention compared to BSCl microsites. Biotic modulation of water dynamics was the result of different mechanisms acting in tandem and often in opposite directions. For instance, biocrusts promoted an exponential behavior during the first stage of the drying curve, but reduced the importance of soil characteristics that accentuate drying rates. Biocrust-dominated microsites gained a similar amount of water than vascular plants, although they lost it faster than vascular plants during dry periods. Our results emphasize the importance of biocrusts for water dynamics in drylands, and illustrate the potential mechanisms behind their effects. They will help to further advance theoretical and modeling efforts on the hydrology of drylands and their response to ongoing climate change.