The negative effect of biocrusts upon annual-plant growth on sand dunes during extreme droughts
The negative effect of biocrusts upon annual-plant growth on sand dunes during extreme droughts
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DOI：
10.1016/j.jhydrol.2013.10.045
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发表时间：
2014-01
影响因子：
6.4
通讯作者：
G. Kidron
中科院分区：
文献类型：
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作者：
G. Kidron
最近的研究结果表明，生物结皮（也被称为生物土壤结皮），提高了下伏土壤的蒸发在沙丘领域内盖夫沙漠（P= 95毫米），试图评估生物结皮植物发芽和生长在干旱年份的影响。在2010/11年和2011/12年期间（极端干旱年份，分别为30.4和35.2毫米），在以前定义的生物结壳类型的5个生境和4个非结壳生境进行了30厘米上层的定期（主要是每周）水分测量。在每个生长季节结束时，测量一年生植物的物种组成、覆盖度和生物量。虽然只有有限的发芽和一年生植物的成熟发生在结壳的栖息地在2011/12年，没有发芽记录在结壳的栖息地在2010/11年，解释了由于生物结壳的蒸发量较低，蒸发增强。相反，一年生植物的发芽和成熟发生在非结壳的栖息地在这两年。与普遍认为沙丘对植物生长是贫瘠和有害的，同时强调生物结皮对植物的积极作用相反，目前的研究结果表明，就年植物生产力而言，在极端干旱年份，无结皮沙丘可能是一年生植物的肥力带。
Following recent findings that biocrusts (known also as biological soil crusts) enhance the evaporation of the underlying soil in the dune field in the Negev Desert (P= 95 mm), an attempt is made to evaluate the effect of biocrust on plant germination and growth during drought years. Periodical (mainly weekly) moisture measurements of the upper 30 cm layer were conducted at 5 habitats of formerly defined biocrust types and at 4 non-crusted habitats during 2010/11 and 2011/12 (extreme drought years with 30.4 and 35.2 mm, respectively). At the end of each growing season, the species composition, cover and biomass of the annual plants was measured. While only limited germination and annual-plant maturation took place in the crusted habitats during 2011/12, no germination was recorded at the crusted habitats during 2010/11, explained by enhanced evaporation due to lower albedo of the biocrusts. In contrast, annual-plant germination and maturation took place at the non-crusted habitats during both years. Contrary to the common view that regards sand dunes as infertile and hostile for plant growth while highlighting the positive role of biocrusts on plants, the current findings indicate that as far as annual plant productivity is concerned, the non-crusted dune may serve as a fertility belt for annuals during extreme drought years.