Mechanisms of Soil Erosion under Forest – The Role of Biological Soil Crusts

森林土壤侵蚀机制——生物结皮的作用

• 批准号: 406370693
• 负责人: Dr. Steffen Seitz
• 金额: --
• 依托单位: Soil Science and Geomorphology work group
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/406370693?language=en
• 关键词: Mechanisms; Soil; Erosion; under; Forest

Soil erosion negatively affects terrestrial ecosystems since humanity started to cultivate land. Most prominent soil losses appear in agricultural environments. This might be one reason why soil erosion under forest is much less in focus of research. Nevertheless, important soil losses can be observed in forests, if the protecting soil surface cover is disturbed e.g. on skid trails after timber harvesting. Those gaps in higher vegetation layers can be quickly colonized by biological soil crusts (biocrusts); assemblages of cyanobacteria, green algae, bryophytes, fungi or lichens. As such, biocrusts are an integral part of erosion prevention under forest. Nevertheless, their influence on soil erosion in temperate climates and especially in forest environments has been largely disregarded and mechanisms and processes to protect the soil are still not well understood. In this respect, we will address the influence of biocrusts on soil erosion after vegetation disturbance by skid trails in a temperate European forest ecosystem (Schönbuch Nature Park, Germany). We hypothesize that (H1) biocrust covers are a major factor in mitigating soil and nutrient losses after vegetation disturbances and (H2) they vary in species composition with different underlying substrates and surrounding forest vegetation and thus affect soil erosion processes differently. Furthermore, we hypothesize that (H3) the protecting effect of biocrusts relies not only on their ability to physically protect the soil surface, but also on reduced soil erodibility by altered soil organic matter content and soil aggregation.To test these hypotheses, we will set up an integrated soil and biocrust diversity study with three experiments. They will comprise measurements with a terrestrial laser scanner and rainfall simulations with micro-scale runoff plots in skid trails (Ex I) to investigate soil and nutrient losses after vegetation disturbances (H1) and the role of species composition and different underlying substrates (H2). An accompanying biodiversity analysis of biocrust communities in the field and by state-of-the-art DNA-barcoding in the laboratory will reveal patterns of biotic soil surface covers. In a second rainfall simulation (Ex II), fast-growing moss species in water suspension will be applied with spraying-up technique on a forest skid trail to test for soil loss from biocrusted soils under controlled conditions (H1 and H2). In a third experiment (Ex III) the effect of biocrusts on soil losses by altering soil physical characteristics such as aggregate stability will be tested (H3). The results of this study will help to attain a better understanding of the role of biocrusts for soil erosion control in temperate European forests including the development and succession of biocrusts after vegetation disturbances. Moreover, they will allow assessing the application of biocrusts (e.g. selected moss species) for soil conservation under forest.

自人类开始开垦土地以来，土壤侵蚀就对陆地生态系统产生了负面影响。最突出的土壤流失出现在农业环境中。这可能是为什么森林下的土壤侵蚀很少成为研究重点的原因之一。然而，如果保护性土壤表层受到干扰，例如在木材采伐后的滑道上，可以在森林中观察到严重的土壤流失。较高植被层中的这些空隙可迅速被生物土壤结皮（生物结皮）、蓝藻、绿色藻类、苔藓植物、真菌或地衣的集合体占据。因此，生物结壳是森林下防止侵蚀的一个组成部分。然而，它们对温带气候特别是森林环境中土壤侵蚀的影响在很大程度上被忽视，保护土壤的机制和过程仍然没有得到很好的理解。在这方面，我们将解决的影响，植被干扰后，在欧洲温带森林生态系统（Schönbuch自然公园，德国）的防滑小径的生物结壳对土壤侵蚀。我们假设，（H1）生物壳覆盖是一个主要因素，在减轻土壤和养分流失后，植被干扰和（H2）他们不同的物种组成与不同的下垫面和周围的森林植被，从而影响土壤侵蚀过程不同。此外，我们假设（H3）生物结皮的保护作用不仅依赖于它们对土壤表面的物理保护能力，而且还依赖于通过改变土壤有机质含量和土壤团聚体来降低土壤可蚀性。它们将包括用地面激光扫描仪进行测量和用滑道中的微型径流小区进行降雨模拟（Ex I），以调查植被扰动后的土壤和养分损失（H1）以及物种组成和不同底层基质的作用（H2）。伴随的生物结壳群落的生物多样性分析在现场和国家的最先进的DNA条形码在实验室将揭示生物土壤表面覆盖的模式。在第二次降雨模拟（Ex II）中，将采用喷雾技术将快速生长的苔藓物种悬浮在水溶液中，置于森林防滑道上，以测试受控条件下（H1和H2）生物结垢土壤的土壤流失。在第三个实验（Ex III）中，将测试生物结壳通过改变土壤物理特性（如团聚体稳定性）对土壤流失的影响（H3）。这项研究的结果将有助于更好地了解生物结皮的作用，在欧洲温带森林土壤侵蚀控制，包括植被干扰后的生物结皮的发展和演替。此外，它们还将有助于评估生物结壳（例如，选定的苔藓物种）在森林土壤保持方面的应用。