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Exposure and sensitivity of other ecosystem services and feedbacks between climate change and land degradation
Published in Mark S. Reed, Lindsay C. Stringer, Land Degradation, Desertification and Climate Change, 2016
Mark S. Reed, Lindsay C. Stringer
It is further important to remember that not all biodiversity is above ground, and that the soil harbours a rich and varied selection of micro-organisms. In drylands, these micro-organisms can often take the form of biological soil crusts (BSC) that cover the top few centimeters of soils. These crusts are composed of complex communities of algae, bacteria, microfungi, lichens and bryophytes. They stabilize the soil and reduce erosion, play a preparatory role in facilitating the colonization of higher plants, and regulate gas fluxes of nitrogen and carbon between the Earth and the atmosphere. Despite these important roles in underpinning the delivery of a range of regulatory and supporting ecosystem services, BSCs and soil microbial communities more generally are rarely given any consideration in conservation planning and assessment. Recent research advances linked to rDNA analysis have hugely improved the speed of analysis such that it has provided new insights into the phylogenetic diversity of soil microbial communities, revealing microbial species that we would not otherwise know about through the use of traditional culturing techniques.
Effects of chemical substances on the rapid cultivation of moss crusts in a phytotron from the Loess Plateau, China
Published in International Journal of Phytoremediation, 2019
Yongsheng Yang, Li Zhang, Xingfang Chen, Wen Wang, Chongfeng Bu, Yingnian Li, Huakun Zhou
Biological soil crusts (BSCs) are highly complex communities composed of a group of organisms dominated by cyanobacteria, green algae, lichens, and mosses (Belnap and Lange 2003). They are widely distributed in arid and semi-arid regions (Belnap 2003a) because of their drought and cold resistance. Due to the biotic components of BSCs, soil physicochemical properties are often improved by their physiological and metabolic activities (Guo et al. 2008) and the special microstructure of BSCs (Lan et al. 2012) accelerate the process of soil formation, enhance soil fertility (Chamizo et al.2012), increase resistance to erosion (Bu et al. 2015b; Yang et al. 2014), and lay the foundation for ecosystem development. According to the dominant species, BSCs can be divided into cyanobacteria crusts, lichen crusts, and moss crusts (Belnap 2002). Moss crusts, which represent the successional climax community of BSCs (Xu et al. 2008b), not only stabilize the soil surface to a greater degree than early successional cyanobacteria, but also provide a number of other ecosystem services, such as increased soil fertility (Chamizo et al. 2012), reduced water and wind erosion (Bu et al. 2015a, 2015b) and enhanced N2 fixation (DeLuca et al. 2002). However, under natural conditions, because the development of BSCs is limited by various environmental resources and vegetation factors (Lan et al. 2012), the development of BSCs is very slow, and it requires several years, even several decades to form the stabilized moss crusts (Belnap 2003b). Meanwhile, moss crusts are very sensitive to various disturbances (such as burning, trampling, and mechanical rolling), and damage to stable, developed moss crusts can easily result in changes in their coverage and functions and easily lead to severe soil erosion (Bu et al. 2013). Unfortunately, moss crusts also need a long time to fully recover after a disturbance (Belnap 1993). Thus, because of the significant ecological roles of moss crusts, the development of viable and economical restoration techniques for moss crusts can be viewed as a pathway to enhance the landscape restoration of ecologically damaged regions (Bowker 2007). To realize the rapid cultivation and restoration of moss crusts and to quickly implement their various positive ecological functions, it is necessary to find the key factors controlling the rapid cultivation of moss crusts.
Ecological restoration of eroded karst utilizing pioneer moss and vascular plant species with selection based on vegetation diversity and underlying soil chemistry
Published in International Journal of Phytoremediation, 2018
J. C. Shen, Z. H. Zhang, R. Liu, Z. H. Wang
Soil formation results from the combined effects of climate, vegetation, topography, substrate material and the process of soil formation changes constantly with vegetation succession (Kang et al. 2010). To a certain extent, a positive succession of plant communities contributes to the process of continuous accumulation of soil nutrients and improvement in soil physical properties; a reversal in succession of plant communities leads to the process of soil degradation (Kang et al. 2010). Complex communities of soil microorganisms with a diversity of functions play a key role in ecosystems, and their activity can provide a good measure of improvement in soil quality. This study determined that microorganisms are negatively affected by extreme rocky diversification and that there are significant differences between microorganisms associated with soil underlying mosses, and microorganisms in soil underlying vascular plants (p < 0.05). Soil is an important habitat for microorganisms, and their metabolic activities can change both physical and chemical soil properties as well as promote the conversion of matter into energy. Therefore, soil microorganisms are essential in the process of improvement of soil fertility. In areas of soil erosion areas, MBC in soil from 1 to 15 cm deep is significantly higher below mosses than below herbs, shrubs or trees. In other words, soil underlying mosses in areas of soil erosion where the soil layer is comparatively thin and relatively infertile appears to provide a more suitable habitat for microorganisms than soil underlying vascular plants. Many consider that soil under herbaceous plants is the most favorable environment for microorganisms (Johansson 1995; Grayston and Campbell 1996; Jiang, Lian et al. 2014), but these findings are inconsistent with this current study where soil under mosses was determined to be the most favorable habitat. Soil structure, water and nutrient status all have important impacts on soil microorganisms (Fierer et al. 2003). Soil erosion presents different challenges: restricted root systems and limited water storage capacity impede survival of microorganisms. Mosses have the potential to increase the soil clay and fine sand content by continuous erosion of underlying limestone rock and by capture and storage of grit and dust, from both windborne sources and from water runoff across rock surfaces (Martinez et al. 2006; Zhao et al. 2006; Zhou et al. 2014). Mosses enhance the water holding capacity of soil biological soil crusts (Duan et al. 2004; Issa et al. 2009) and improve the nutrient status of surface soil (Ayres et al. 2006; Zhao et al. 2006). Metabolites produced by living mosses and organic matter from dead mosses are beneficial to microorganisms (Singh et al. 1972; Li and Zhang 2009; Zhang, Zhang et al. 2010), providing both a favorable environment and an energy source.