Spatial and temporal distribution of cyanobacterial soil crusts in the Kalahari: Implications for soil surface properties

Thomas, Andrew D.; Dougill, Andrew J.

doi:10.1016/j.geomorph.2006.03.029

Cited by 103 publications

(78 citation statements)

References 32 publications

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“…They form the major component of microbiotic soil crusts in arid environments (Issa et al 2007). Cyanobacterial soil crusts improve soil biochemical and physical properties -they have a higher organic matter and nitrogen content, and maintain surface stability and decrease the effect of erosion on dryland soils (Thomas and Dougill 2007). Moreover, cyanobacterial crusts increase water retention capacity of soils (Issa et al 2007).…”

Section: Rehabilitation Of Degraded Croplandsmentioning

confidence: 99%

Rehabilitation of degraded dryland ecosystems – review

Yirdaw¹,

Tigabu²,

Monge³

2017

Silva Fenn.

114

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Highlights• The prospect of restoring degraded drylands is technically promising.• The forest landscape restoration concept can be used as the overarching rehabilitation framework.• Development of process-based models that forecast rehabilitation outcomes is needed.• Rehabilitation methodologies developed for moist areas are not necessarily suitable for drylands.• More data is needed on cost-benefit analysis of rehabilitation interventions. AbstractLand degradation is widespread and a serious threat affecting the livelihoods of 1.5 billion people worldwide of which one sixth or 250 million people reside in drylands. Globally, it is estimated that 10-20% of drylands are already degraded and about 12 million ha are degraded each year. Driven by unsustainable land use practices, adverse climatic conditions and population increase, land degradation has led to decline in provision of ecosystem services, food insecurity, social and political instability and reduction in the ecosystem's resilience to natural climate variability. Several global initiatives have been launched to combat land degradation, including rehabilitation of degraded drylands. This review aimed at collating the current state-of-knowledge about rehabilitation of degraded drylands. It was found that the prospect of restoring degraded drylands is technically promising using a suite of passive (e.g. area exclosure, assisted natural regeneration, rotational grazing) and active (e.g. mixed-species planting, framework species, maximum diversity, and use of nurse tree) rehabilitation measures. Advances in soil reclamation using biological, chemical and physical measures have been made. Despite technical advances, the scale of rehabilitation intervention is small and lacks holistic approach. Development of processbased models that forecast outcomes of the various rehabilitation activities will be useful tools for researchers and practitioners. The concept of forest landscape restoration approach, which operates at landscape-level, could also be adopted as the overarching framework for rehabilitation of degraded dryland ecosystems. The review identified a data gap in cost-benefit analysis of rehabilitation interventions. However, the cost of rehabilitation and sustainable management of drylands is opined to be lower than the losses that accrue from inaction, depending on the degree of degradation. Thus, local communities' participation, incorporation of traditional ecological knowledge, clear division of tasks and benefits, strengthening local institutions are crucial not only for cost-sharing, but also for the long-term success of rehabilitation activities.

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Section: Rehabilitation Of Degraded Croplandsmentioning

confidence: 99%

Rehabilitation of degraded dryland ecosystems – review

Yirdaw¹,

Tigabu²,

Monge³

2017

Silva Fenn.

114

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“…On Mars, the presence of abiotic crusts may also be important for limiting present-day dune activity (Schatz et al, 2006). On Earth, biological soil crusts are common in arid and semi-arid dune fields (e.g., Negev : Tsoar, 2008; Kalahari: Thomas and Dougill, 2007;China: Li et al, 2007). They can be formed by communities of several types of microphytes including mosses, lichens, fungi, green and bluegreen algae, as well as bacteria.…”

Section: Discriminating Dune Vegetation Soil Crust and Open Sandmentioning

confidence: 99%

Remote sensing and spatial analysis of aeolian sand dunes: A review and outlook

Hugenholtz

Levin

Barchyn

et al. 2012

Earth-Science Reviews

177

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“…Biocrusts need to reach a defined concentration of chlorophyll concentration before cyanobacterial secretion of EPS occurs, and then it can take several weeks before the inorganic layer is added (Hu et al, 2002). The contribution of EPS to crust structure can be measured by crust compressive strength, which also relates well to crust type, biocrust development and 15 the quality of the binding of soil particles (McKenna Neuman and Rice, 2002;Thomas and Dougill, 2007;Wang et al, 2006). At J-A seasonal carbon and nitrogen were always lower in the biocrusts from the dunes compared to those from the other soil types.…”

Section: Biocrust Developmentmentioning

confidence: 99%

Microbial Biobanking Cyanobacteria-rich topsoil facilitates mine rehabilitation

Williams¹,

Schneemilch²,

Chilton³

et al. 2017

Preprint

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10Mining rehabilitation requires key solutions to complex issues relating to ecosystem function. In arid landscapes, the removal or disturbance of topsoil incorporating soil microbial communities can result in a shift in ecosystem function. Soil surfaces in arid regions are protected by biocrusts that regulate soil moisture, sequester carbon and fix significant quantities of atmospheric nitrogen. Cyanobacteria often dominate these bioactive surfaces and work as ecosystem engineers in that they are in sufficiently large quantities they initiate biocrust establishment and facilitate soil surface stabilisation. Cyanobacterial 15 exopolymeric secretions form cohesive and protective layers at the soil surface that minimise wind erosion. This research encompassed soil microbial community profiling (using a polyphasic approach) with a focus on 'biobanking' topsoil for rehabilitation purposes. The research was in collaboration with Iluka Resources at Jacinth-Ambrosia (J-A) mineral sand mine located in a semi-arid chenopod shrubland in southern Australia. At J-A diverse biocrusts included a significant representation of cyanobacteria, lichens and mosses that inhabited nearly half of all soil surfaces. Cyanobacterial community structure at J-A 20 was comprised of a variety of species having a range of attributes that contributed to their resilience and survival in an arid environment. Stockpiling from shallow scrapings and storage at low profiles appeared beneficial in microbial biobanking cyanobacterial inoculum that would facilitate recovery over time. These studies have provided information for the establishment of a monitoring program that assesses the re-establishment of biocrusts following mining. Following soil stockpiling that occurred during the mining process, cyanobacterial taxa recovered at different rates. Cyanobacterial strategies 25 central to survival include exopolymeric production, spectral adaptation, nitrogen fixation and motility. Biocrust reestablishment during mining rehabilitation relies on the role of cyanobacteria as a means of early soil stabilisation. Provided there is adequate cyanobacterial inoculum in the topsoil stockpiles their growth and the subsequent crust formation should take place largely unassisted. Ongoing monitoring of biocrust recovery is important as it provides an effective means of measuring important soil restoration processes. 30Biogeosciences Discuss., https://doi

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Spatial and temporal distribution of cyanobacterial soil crusts in the Kalahari: Implications for soil surface properties

Cited by 103 publications

References 32 publications

Rehabilitation of degraded dryland ecosystems – review

Rehabilitation of degraded dryland ecosystems – review

Remote sensing and spatial analysis of aeolian sand dunes: A review and outlook

Microbial Biobanking Cyanobacteria-rich topsoil facilitates mine rehabilitation

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