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biological soil crust distribution in Artemisia ordosica communities along a grazing pressure gradient in Mu Us Sandy Land, Northern China

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Journal of Arid Land 2013年第2期5卷 172-179页

作者： JunHong ZHANG Bo WU YongHua LI WenBin YANG YaKai LEI HaiYan HAN Ji HE Institute of Desertification Studies Chinese Academy of Forestry College of Forestry Henan Agricultural University

This study investigated the distribution pattern of biological soil crust （BSC） in Artemisia ordosica communities in Mu Us Sandy Land. Three experimental sites were selected according to grazing pressure gradient. In each experimental site, the total vegetation cover, A. ordosica cover, BSC cover, litter-fall cover, BSC degree of fragmentation, BSC thickness and soil properties were investigated in both fixed and semi-fixed sand dunes and simultaneously analyzed in the laboratory. The results showed that at the same grazing pressure, BSC cover and composition were significantly affected by the fixation degree of sand dunes. In addition, BSC cover in the fixed sand dunes was 83.74% on average, whereas it is proportionally dominated by 28% mosses, 21% lichens, and 51% algae. Meanwhile, BSC cover in the semi-fixed sand dunes was 23.54% on average, which is proportionally domi- nated by 6.3% mosses, 2.5% lichens, and 91.2% algae. Fine sand, organic matter, and total nitrogen （N） contents in the fixed sand dunes were all significantly higher than those in the semi-fixed sand dunes. Litter-fall cover de- creased along the grazing pressure gradient, whereas BSC fragmentation degree increased. Fine sand content decreased along with the increase of grazing pressure, whereas medium sand content increased in both fixed and semi-fixed dunes. The organic matter and total N contents in the no grazing site were significantly higher than those in light and normal grazing sites. However, there were no significant differences between the light and normal grazing sites. In addition, there were also no significant differences in BSC thickness between the light and normal grazing sites in the fixed sand dunes. However, a significant decrease was observed in both BSC cover and thick- ness in the normal grazing site. The BSC in the semi-fixed dunes was more sensitive to disturbance.

关键词： Artemisia ordosica community biological soil crust grazing pressure soil properties Mu Us Sandy Land

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Long-term changes in biological soil crust cover and composition

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Ecological Processes 2013年第1期2卷 54-63页

作者： Eva Dettweiler-Robinson Jeanne M Ponzetti Jonathan D Bakker Department of Biology University of New MexicoMSC0320201 University of New MexicoAlbuquerqueNM 98131U.S.A. 2914 Central St.SE OlympiaWA 98501U.S.A. School of Environmental and Forest Sciences University of WashingtonBox 354115SeattleWA98195-4115U.S.A.

Introduction:Communities change over time due to disturbances,variations in climate,and species invasions.biological soil crust communities are important because they contribute to erosion control and nutrient cycling.crust types may respond differently to changes in environmental conditions:single-celled organisms and bryophytes quickly recover after a disturbance,while lichens are slow growing and dominate favorable sites.Community change in crusts has seldom been assessed using repeated measures.For this study,we hypothesized that changes in crust composition were related to disturbance,topographic position,and invasive vegetation.Methods:We monitored permanent plots in the Columbia Basin in 1999 and 2010 and compared changes in crust composition,cover,richness,and turnover with predictor variables of herbivore exclosure,elevation,heat load index,time since fire,presence of an invasive grass,and change in cover of the invasive grass.Results:Bryophytes were cosmopolitan with high cover.Dominant lichens did not change dramatically.Indicator taxa differed by monitoring year.Bryophyte and total crust cover declined,and there was lower turnover outside of herbivore exclosures.Lichen cover did not change significantly.Plots that burned recently had high turnover.Increase in taxon richness was correlated with presence of an invasive grass in 1999.Change in cover of the invasive grass was positively related to proportional loss and negatively related to gain.Conclusions:Composition and turnover metrics differed significantly over 11 years,though cover was more stable between years.This study can be a baseline for assessing change in crust composition due to anthropogenic influences.

关键词： biological soil crust Columbia basin Composition change Taxa turnover rate Fire Bromus tectorum Livestock exclosure

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Reduction of the wind erosion potential in dried-up lakebeds using artificial biocrusts

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Frontiers of Earth Science 2022年第4期16卷 865-875页

作者： Hossein KHEIRFAM Maryam ROOHI Department of Range and Watershed Management Faculty of Natural ResourcesUrmia UniversityUrmia ***Iran Department of Environmental Sciences Urmia Lake Research InstituteUrmia UniversityUrmia ***Iran Microbiology Laboratory Expert Artemia&Aquaculture Research InstituteUrmia UniversityUrmia ***Iran

The artificial creation of biocrusts can be a rapid and pervasive solution to reduce wind erosion potential(WEP)in dried-up lakes(e.g.,Lake Urmia).So,in this study,we created a biocrust by the inoculation of bacteria and cyanobacteria on trays filled by soils collected from the dried-up bed of Lake Urmia,Iran,to reduce WEP in laboratory conditions.We used the wind erodible fraction of soil(EF)and soil crust factor(SCF)equations to calculate the WEP of the treated soils.EF and SCF were decreased(pcrusts created by soil inoculation,especially with the co-using of bacteria and cyanobacteria,significantly reduced the WEP of a newly dried-up lakebed.Furthermore,we found that inoculation decreased the WEP of the study soil by increasing the soil organic matter content from 3.7 to 5 fold.According to scanning electron microscopy images,the inoculated microorganisms,especially cyanobacteria,improved soil aggregation by their exopolysaccharides and filaments;thus,they can be used with other factors to estimate the soil erodibility in well-developed biocrusts.The inoculation technique could be considered as a rapid strategy in stabilizing lakebeds against wind force.However,it should be confirmed after additional experiments using wind tunnels under natural conditions.

关键词： biological soil crust dried-up lakes dust storms flowing-sands soil cyanobacteria

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Ability of soil bacterial composition as an indicator of levels of soil erosion in a badland

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International Journal of Sediment Research 2022年第4期37卷 493-504页

作者： Gaetano Guida Vincenzo Palmeri Luca Settanni Raimondo Gaglio Marco Tolone Vito Ferro Department of Agricultural Food and Forest SciencesUniversity of Palermo

Calanchi(plural of calanco) are typical Italian badlands created by a combination of morphogenetic processes(rill and interrill erosion, gullying, piping, and mass movements) mainly originated by the effect of water. Calanchi are characterized by the sparse and patchy distribution of vegetation, and, in interplant areas, the soil surface is colonized by an association of organisms known as biological soil crust(BSC). A morphometric analysis of 45 basins in the studied calanchi area, based on a high-resolution digital elevation model, showed those basins are sediment removal systems characterized by rapid and relevant erosion processes. The goal of the current research is to evaluate the bacterial composition of BSC and to recognize its signature of land degradation processes in soil samples by a microbiological analysis(culture-dependent and culture-independent approaches). soil bacterial distribution was investigated by a culture-independent approach, applying Illumina technology in soils with different vegetation cover. Four species were detected in site A(bare soil). In sites B(sparse vegetation) and C(densely vegetated soil) 19 and 18 bacterial taxa were detected, respectively. Sites B and C were characterized by 17 species in common. The microbial communities detected at sites B and C are typical of environments unable to support vegetation and microorganisms that are not specialized to live in these environments. Biodiversity analysis of the bacterial communities of biocrusts, done using richness and evenness indices, confirmed that the composition of the BSC communities can be a signature of the intensity of soil erosion processes.

关键词： Calanchi biological soil crust soil bacteria Vegetation cover Water erosion

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Weathering of Carbonate Rocks by biological soil crusts in Karst Areas

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Journal of Earth Science 2014年第4期25卷 662-667页

作者： Ye Chen Bin Lian Zuoying Yin Yuan Tang Key Laboratory of Karst Environment and Geological Hazard Prevention School of Chemistry and Chemical EngineeringGuizhou University Jiangsu Key Laboratory for Microbes and Functional Genomics Jiangsu Engineering and Technology Research Center for Microbiology College of Life Science Nanjing Normal University Puding Karst Ecosystem Research Station State Key Laboratory of Environmental GeochemistryInstitute of GeochemistryChinese Academy of Sciences

The weathering of carbonate rocks by biological soil crusts （BSC） in karst areas is very common. It is helpful to understand the weathering mechanisms and processes for avoiding karst rock-desertification. The weathering of carbonate rocks by BSC in karst areas, namely the expansion, contraction and curl resulting from environmental wetting-drying cycles, was investigated and ana- lyzed in this paper. The bulk density, area and thickness of BSC were determined and the weathering amount of limestone and dolomite per unit area of BSC was calculated as 3 700 and 3 400 g·m-2; the amount of biomass on the surface of limestone and dolomite was calculated as 1 146 and 1 301 g·m-2, respectively. Such an increased weathering amount was not only the result of chemical and physical weathering of BSC on carbonate rocks, but also the attachment and cementation of BSC to clay particles, dust-fall, sand particles, solid particles brought by strong air currents, wind and other factors in the surrounding environment, which may also be related to the special environment and the special time period. Based on the results obtained, a weathering mode of BSC is studied, and the mechanisms of weathering by BSC are discussed. In conclusion, we suggest that the mechanical force exerted by the expansion and constriction of gelatinous and mucilaginous substances through wetting and drying of BSC play a significant role in the physical weathering process of the carbonate substrates.

关键词： biological soil crust dolomite limestone weathering amount biomass.

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Precipitation and soil particle size co-determine spatial distribution of biological soil crusts in the Gurbantunggut Desert, China

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Journal of Arid Land 2018年第5期10卷 701-711页

作者： WU Lin ZHANG Yuanming Hubei University for Nationalities Enshi 445000 China Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China

biological soil crusts （BSCs） are bio-sedimentary associations that play crucial ecological roles in arid and semi-arid regions. In the Gurbantunggut Desert of China, more than 27% of the land surface is characterized by a predominant cover of lichen-dominated BSCs that contribute to the stability of the desert. However, little is known about the major factors that limit the spatial distribution of BSCs at a macro scale. In this study, the cover of BSCs was investigated along a precipitation gradient from the margins to the center of the Gurbantunggut Desert. Environmental variables including precipitation, soil particle size, soil pH, electrical conductivity, soil organic carbon, total salt, total nitrogen, total phosphorus and total potassium were analyzed at a macro scale to determine their association with differing assemblages of BSCs （cyanobacteria crusts, lichen crusts and moss crusts） using constrained linear ordination redundancy analysis （RDA）. A model of BSCs distribution correlated with environmental variables that dominated the first two axes of the RDA was constructed to clearly demonstrate the succession stages of BSCs. The study determined that soil particle size （represented by coarse sand content） and precipitation are the most significant drivers influencing the spatial distribution of BSCs at a macro scale in the Gurbantunggut Desert. The cover of lichen and moss crusts increased with increasing precipitation, while the cover of cyanobacteria crusts decreased with increasing precipitation. The cover of lichen and moss crusts was negatively associated with coarse sand content, whereas the cover of cyanobacteria crusts was positively correlated with coarse sand content. These findings highlight the need for both the availability of soil moisture and a relatively stable of soil matrix, not only for the growth of BSCs but more importantly, for the regeneration and rehabilitation of disturbed BSC communities in arid and semi-arid lands. Thereby, this study will provide a theory basis to effectively

关键词： biological soil crust distribution macro scale redundancy analysis （RDA） disturbance temperate desert

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biological crust in sand and dust storm source areas of Asia and its impact on dust emission

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Advances in Climate Change Research 2021年第3期12卷 395-408页

作者： ZHANG Jian ZHOU Chun-Hong GUI Hai-Lin ZHANG Xiao-Ye State Key Laboratory of Severe Weather and Key Laboratory of Atmospheric Chemistry of China Meteorological Administration&Institute of Atmospheric Composition Chinese Academy of Meteorological SciencesBeijing100081China National Meteorological Center China Meteorological AdministrationBeijing100081China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen361021China

Even though the biological crusts are critical to dust emissions,no sand and dust forecast model have considered the impacts of the biological crust in dust emission scheme.This situation mainly comes from two scientific difficulties:there is no large scale regional biological crust data available that can be used in the forecast model;there is no quantification of how biological crusts impact on sand emission.In this way,we studied the distribution of biological soil crust in sand and dust storm source areas of Central and East Asia using Moderate Resolution Imaging Spectroradiometer satellite surface reflectance data collected in 2000—2019 to determine its potential impact on dust emission according to two empirical schemes.We further evaluated the relationships between soil crust coverage,roughness length,and dust emission to study SDS source areas.We found that biological crust is widely distributed in SDS source areas of Central and East Asia,with coverage rates of 19.8%in Central Asian deserts,23.1%in the Gobi Desert,and 17.3%—32.8%in Chinese deserts(p>0.05).Cyanobacteria and lichen coverage has increased in Chinese deserts,reflecting the recent impacts of the Project of Returning Farmland to Grassland and Farmland to Forests.However,biological soil crust coverage has not increased in Central Asian deserts or the Gobi Desert,and that in Central Asian deserts continues to decrease,demonstrating the complexity of the combined effects of human activities and climate change on its distribution.biological soil crust increased the roughness length of Central and East Asian SDS source areas by 0.14—0.62 mm.The suppression of dust emission due to biological soil crust did not change among years during the study period.The horizontal and vertical dust flux inhibition coefficient(DFIC)were 2.0—11.0 and 1.7—2.9(p>0.05),respectively,clearly showing a suppressive effect.Improvement of the ecological environment in some deserts can lead to the ability of these crusts to inhibit dust erosion errors that must be considered

关键词： biological soil crust Dust emission Satellite retrieval Sand and dust storm source Central and East Asia

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Denitrification from nitrogen-fixing biologically crusted soils in a cool desert environment,southeast Utah,USA

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Ecological Processes 2013年第1期2卷 156-164页

作者： Nichole N Barger Sarah C Castle Gavin N Dean Department of Ecology and Evolutionary Biology University of ColoradoCampus Box 334BoulderCO 80309-0334USA Department of Ecosystem and Conservation Sciences College of Forestry and ConservationUniversity of MontanaMissoulaMT59812USA.

Introduction:Nitrogen fixation by microorganisms within biological soil crust(“biocrust”)communities provides an important pathway for N inputs in cool desert environments where soil nutrients are low and symbiotic N-fixing plants may be rare.Estimates of N fixation in biocrusts often greatly exceed that of N accretion rates leading to uncertainty regarding N loss pathways.Methods:In this study we examined nitrogen fixation and denitrification rates in biocrust communities that differed in N fixation potential(low N fixation=light cyanobacterial biocrust,high N fixation=dark cyanolichen crust)at four temperature levels(10,20,30,40°C)and four simulated rainfall levels(0.05,0.2,0.6,1 cm rain events)under controlled laboratory conditions.Results:Acetylene reduction rates(AR,an index of N fixation activity)were over six-fold higher in dark crusts relative to light crusts.Dark biocrusts also exhibited eight-fold higher denitrification rates.There was no consistent effect of temperature on denitrification rates,but there was an interactive effect of water addition and crust type.In light crusts,denitrification rates increased with increasing water addition,whereas the highest denitrification rates in dark crusts were observed at the lowest level of water addition.Conclusions:These results suggest that there are no clear and consistent environmental controls on short-term denitrification rates in these biologically crusted soils.Taken together,estimates of denitrification from light and dark biocrusts constituted 3 and 4%of N fixation rates,respectively suggesting that losses as denitrification are not significant relative to N inputs via fixation.This estimate is based on a previously published conversion ratio of ethylene produced to N fixed that is low(0.295),resulting in high estimates of N fixation.If future N fixation studies in biologically crusted soils show that these ratios are closer to the theoretical 3:1 ratio,denitrification may constitute a more significant loss pathway relative to N fixed.

关键词： biological soil crust Colorado Plateau Cool desert Denitrification Nitrogen fixation soil nitrogen cycling

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Ammonia-oxidizing archaea and bacteria are structured by geography in biological soil crusts across North American arid lands

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Ecological Processes 2013年第1期2卷 98-107页

作者： Yevgeniy Marusenko Scott T Bates Ian Anderson Shannon L Johnson Tanya Soule Ferran Garcia-Pichel School of Life Sciences Arizona State UniversityP.O.Box 874501TempeAZ 85287-4501USA Cooperative Institute for Researchin Environmental Sciences University of ColoradoBoulderCO80309USA Bioscience Division B-11Los Alamos National LaboratoryLos AlamosNM87545USA Department of Biology Indiana University-Purdue UniversityFort WayneINUSA

Introduction:biological soil crusts(BSCs)can dominate surface cover in dry lands worldwide,playing an integral role in arid land biogeochemistry,particularly in N fertilization through fixation and cycling.Nitrification is a characteristic and universal N transformation in BSCs that becomes important for the export of N beyond the microscopic bounds of the crust itself.The contribution of ammonia-oxidizing bacteria(AOB)in BSCs has been shown,but the role and extent of the recently discovered ammonia-oxidizing archaea(AOA)have not.Methods:We sampled various types of crusts in four desert regions across the western United States and characterized the composition and size of ammonia-oxidizing communities using clone libraries and quantitative PCR targeting the amoA gene,which codes for the ammonia monooxygenase enzyme,universally present in ammonia-oxidizing microbes.Results:All archaeal amoA sequences retrieved from BSCs belonged to the Thaumarchaeota(Nitrososphaera associated Group I.1b).Sequences from the Sonoran Desert,Colorado Plateau,and Great Basin were indistinguishable from each other but distinct from those of the Chihuahuan Desert.Based on amoA gene abundances,archaeal and bacterial ammonia oxidizers were ubiquitous in our survey,but the ratios of archaeal to bacterial ammonia oxidizers shifted from bacterially dominated in northern,cooler deserts to archaeally dominated in southern,warmer deserts.Conclusions:Archaea are shown to be potentially important biogeochemical agents of biological soil crust N cycling.Conditions associated with different types of BSCs and biogeographical factors reveal a niche differentiation between AOA and AOB,possibly driven by temperature.

关键词： biological soil crust Desert Arid amoA Ammonia oxidation Nitrification Nitrogen cycle Thaumarchaeota

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Lichen species dominance and the resulting photosynthetic behavior of Sonoran Desert soil crust types(Baja California,Mexico)

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Ecological Processes 2013年第1期2卷 64-72页

作者： Burkhard Büdel Mercedes Vivas Otto L Lange Plant Ecology and Systematics Biology DepartmentUniversity of KaiserslauternP.O.Box 3049D-67653KaiserslauternGermany Department of Plant Science Faculty of PharmacyUniversidad Complutense de Madrid Plaza Ramóny Cajal28040MadridSpain Julius-von-Sachs-Institut für Biowissenschaften University of WürzburgJulius-von-Sachs-Platz 3D-97082WürzburgGermany.

Introduction:Lichen dominated biological soil crusts(BSCs)occur over large areas in the Sonoran Desert of the southwestern USA and northwest Mexico.In Baja California BSCs show a distinct patchiness and several types can be distinguished.Two chlorolichen-and two cyanolichen-dominated BSCs were selected.We hypothesize that patchiness and the resulting domination of certain functional lichen groups will result in patchiness of photosynthetic CO_(2)-uptake related to environmental factors as well.Methods:Four different soil crust samples were placed in cuvettes and their CO_(2) exchange was recorded in an open system with an infrared gas analyzer.Air blown over the BSCs had a controlled CO_(2) content of 350 ppm.Four cuvettes were operated in parallel.Photosynthetic CO2 exchange was continually recorded throughout the experiment.Results:Besides the dominating chlorolichens Psora decipiens and Placidium squamulosum and the cyanolichens Peltula patellata and P.richardsii,several other lichen species and 12 cyanobacterial species were found in the biological soil crusts sampled.The chlorolichen BSCs already gained positive net photosynthesis with high air humidity alone,while the cyanolichen types did not,but showed smaller CO_(2)-uptake depression after water suprasaturation.Such specific net photosynthesis responses to mode of hydration and to crust water content seem to correlate with precipitation characteristics of their habitat.Conclusions:Species specific photosynthetic performance related to activation of respiration and net photosynthesis as well as to crust water content help to explain niche occupation and species composition of BSCs.Different functional types have to be considered when they have a patchy distribution.

关键词： biological soil crust Lichens Cyanobacteria Photosy

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