Composition and Macrostructure of Biological Soil Crusts

Colesie, Claudia; Felde, Vincent J.M.N.L.; Büdel, Burkhard

doi:10.1007/978-3-319-30214-0_9

Cited by 32 publications

(25 citation statements)

References 36 publications

(36 reference statements)

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“…Likewise, recovery rates of BC are in the same range as those estimated by Read et al (2011) in Australia, although Xiao et al (2014) observed lower recovery rates in China. Bare soils, which are never sterile in nature (Colesie et al, 2016), normally present cyanobacteria (Maier et al, 2018), some of which are considered to be pioneers capable of initiating biocrusts formation (Garcia-Pichel & Wojciechowski, 2009). Temporal changes in the relative abundance of LC and MS in the medium aridity site agree with the general model of ecological succession of biocrusts.…”

Section: Biocrusts Recover In a Few Years After Grazing Abandonmentmentioning

confidence: 99%

“…Temporal changes in the relative abundance of LC and MS in the medium aridity site agree with the general model of ecological succession of biocrusts. Bare soils, which are never sterile in nature (Colesie et al, 2016), normally present cyanobacteria (Maier et al, 2018), some of which are considered to be pioneers capable of initiating biocrusts formation (Garcia-Pichel & Wojciechowski, 2009).…”

Section: Biocrusts Recover In a Few Years After Grazing Abandonmentmentioning

confidence: 99%

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Grazing pressure interacts with aridity to determine the development and diversity of biological soil crusts in Patagonian rangelands

et al. 2019

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Grazing is directly related to land degradation and desertification in global drylands.Grazing impacts on vascular plants, reasonably well-known, depend on its intensity and are modulated by local aridity conditions. However, we do not know how the interplay of grazing intensity and aridity affect biocrusts, topsoil assemblages dominated by cyanobacteria, lichens, and mosses that provide key ecosystem services in drylands. Here, we determined how grazing affects biomass, total cover, and richness of biocrust structural types across a regional aridity gradient in the Patagonian steppe. On average, grazing by sheep reduced biocrust biomass, total cover and richness of structural types by 55, 90, and 59%, respectively. In general, high grazing pressures had a larger impact on biocrusts than moderate or light grazing pressures.For example, biocrust cover was reduced by 85, 89, and 98% by light, moderate, and high grazing pressures, respectively. Although a slightly different response to grazing was observed under low aridity conditions, these more benign climatic conditions did not compensate for the negative effects of trampling by domestic animals on biocrusts.Nonetheless, estimated biocrust recovery rates under medium aridity conditions were faster than previously thought: it took 24, 18, and 58 years to double biocrust biomass, total cover, and richness of structural types. Sheep cannot be just removed in Patagonian rangelands because the production of meat and wool represents the main local economic activity. But landowners must consider our results to protect the ecosystem functions and services provided by biocrusts for future generations to come. K E Y W O R D Saridity, biocrusts, grazing intensity, Patagonian steppe, recovery rates

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Section: Biocrusts Recover In a Few Years After Grazing Abandonmentmentioning

confidence: 99%

Section: Biocrusts Recover In a Few Years After Grazing Abandonmentmentioning

confidence: 99%

Grazing pressure interacts with aridity to determine the development and diversity of biological soil crusts in Patagonian rangelands

et al. 2019

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“…They cover approximately 12% of Earth's terrestrial surface (Rodriguez-Caballero et al, 2018). Although they are widespread and can be found in all macroclimatic regions (Colesie et al, 2016), they are of special importance to dryland ecosystems because the biocrust organisms stabilize the soil against erosive forces through exopolysaccharide production (EPS) and increase soil fertility via the export of C and N to the soils they cover (Johnson et al, 2007;Strauss et al, 2012) and through the lixiviation of many other elements (Beraldi-Campesi et al, 2009). Biocrust organisms have developed various survival mechanisms in order to cope with a multitude of harsh environmental conditions (Pócs, 2009) that include high radiation (Garcia-pichel and Castenholz, 1991) and water scarcity (Rajeev et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

In Situ X-Ray Tomography Imaging of Soil Water and Cyanobacteria From Biological Soil Crusts Undergoing Desiccation

Couradeau

Felde

Parkinson

et al. 2018

Front. Environ. Sci.

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Biological soil crusts (biocrusts) are millimeter-sized microbial communities developing on the topsoils of arid lands that cover some 12% of Earth's continental area. Biocrusts consist of an assemblage of mineral soil particles consolidated into a crust by microbial organic polymeric substances that are mainly produced by filamentous bundle-forming cyanobacteria, among which Microcoleus vaginatus is perhaps the most widespread. This cyanobacterium is the primary producer for, and main architect of biocrusts in many arid soils, sustaining the development of a diverse microbial community. Biocrusts are only active when wet, and spend most of their time in a state of desiccated quiescence, from which they can quickly recover upon wetting. Despite their ecological importance for arid ecosystems, little is known about the mechanisms that allow biocrust organisms to endure long periods of dryness while remaining viable for rapid resuscitation upon wetting. We had previously observed the persistence of significant rates of light-dependent carbon fixation in apparently dry biocrusts dominated by M. vaginatus, indicating that it may be able to remain hydrated against a background soil of very low water potential. One potential explanation for this may be that the abundant exopolysaccharide sheaths of M. vaginatus can preferentially retain moisture thus slowing the water equilibration with the surrounding soil allowing for extended activity periods. In order to test this hypothesis we aimed to develop methodologies to visualize and quantify the water dynamics within an undisturbed biocrust undergoing desiccation. We used synchrotron based X-ray microtomography and were able to resolve the distribution of air, liquid water, mineral particles and cyanobacterial bundles at the microscale. We could demonstrate the formation of steep, decreasing gradients of water content from the cyanobacterial bundle surface outward, while the bundle volume remained stable, as the local bulk water content decreased linearly, hence demonstrating a preferential retention of water in the microbes. Our data also suggest a transfer of hydration water from the EPS sheath material into the cyanobacterial filament as Couradeau et al. X-Ray Microtomography of a Biocrust Undergoing Desiccation desiccation progresses. This work demonstrates the value of X-ray tomography as a tool to study microbe-scale water redistribution in biocrusts.

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“…The relatively low seedling densities in barren microsites and high seedling densities in biocrust and thin moss microsites agree with earlier colonization studies of birch (Aradóttir 1991), willows (Svavarsdóttir 2006;Muller et al 2011), and several other species (Elmarsdottir et al 2003;Karlsdóttir & Aradóttir 2006). According to Colesie et al (2016), both the microsite types designated as "biocrust" and "moss" in our study can be designated as biological soil crust or biocrust; the first was dominated by liverworts, especially Anthelia spp., and the latter was dominated by bryophytes ( Fig. 5).…”

Section: Colonization In Different Micrositesmentioning

confidence: 81%

Colonization of woodland species during restoration: seed or safe site limitation?

Aradóttir

Halldórsson²

2017

Restoration Ecology

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A strategy of assisted natural regeneration uses selective restoration interventions to remove potential barriers to passive natural regeneration and succession toward target ecosystems. In woodland restoration, this may involve the planting of woodland clusters that serve as seed sources for further colonization and/or site amelioration to enhance colonization and growth of the target species. We tested the importance of seed and safe site limitations for the colonization of birch and willows in experimental treatments representing a matrix of revegetation (+/−) and planted birch and willow clusters (+/−) on an eroded area in South Iceland. The revegetation was initiated in the fall of 1999 and clusters of birch and willows planted in 2002. Density of birch and willow seedlings and their distribution among microsites was surveyed in 2005, 2006, 2010, and 2015. Willow seedlings were first noted in 2006 but birch seedlings in 2010. In 2015, seedling density in revegetated plots with planted clusters was over 20 times greater than that of revegetated plots without clusters, indicating a strong seed limitation. No seedlings were found in plots that had not been revegetated, showing very strong microsite limitation. However, revegetation increased the cover of biological soil crust and other microsites favorable for seedling establishment. The results demonstrate that both seed and safe site limit the colonization of birch and willows, key species in woodland restoration, and highlight the importance of identifying barriers to spontaneous succession before selecting restoration strategies.

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Composition and Macrostructure of Biological Soil Crusts

Cited by 32 publications

References 36 publications

Grazing pressure interacts with aridity to determine the development and diversity of biological soil crusts in Patagonian rangelands

Grazing pressure interacts with aridity to determine the development and diversity of biological soil crusts in Patagonian rangelands

In Situ X-Ray Tomography Imaging of Soil Water and Cyanobacteria From Biological Soil Crusts Undergoing Desiccation

Colonization of woodland species during restoration: seed or safe site limitation?

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