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Elliott DR, Thomas AD, Hoon SR, Sen R. Spatial organisation of fungi in soil biocrusts of the Kalahari is related to bacterial community structure and may indicate ecological functions of fungi in drylands. Front Microbiol 2024; 15:1173637. [PMID: 38741739 PMCID: PMC11090246 DOI: 10.3389/fmicb.2024.1173637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 02/27/2024] [Indexed: 05/16/2024] Open
Abstract
Biological soil crusts, or biocrusts, are microbial communities found in soil surfaces in drylands and in other locations where vascular plant cover is incomplete. They are functionally significant for numerous ecosystem services, most notably in the C fixation and storage due to the ubiquity of photosynthetic microbes. Whereas carbon fixation and storage have been well studied in biocrusts, the composition, function and characteristics of other organisms in the biocrust such as heterotrophic bacteria and especially fungi are considerably less studied and this limits our ability to gain a holistic understanding of biocrust ecology and function. In this research we characterised the fungal community in biocrusts developed on Kalahari Sand soils from a site in southwest Botswana, and combined these data with previously published bacterial community data from the same site. By identifying organisational patterns in the community structure of fungi and bacteria, we found fungi that were either significantly associated with biocrust or the soil beneath biocrusts, leading to the conclusion that they likely perform functions related to the spatial organisation observed. Furthermore, we showed that within biocrusts bacterial and fungal community structures are correlated with each other i.e., a change in the bacterial community is reflected by a corresponding change in the fungal community. Importantly, this correlation but that this correlation does not occur in nearby soils. We propose that different fungi engage in short-range and long-range interactions with dryland soil surface bacteria. We have identified fungi which are candidates for further studies into their potential roles in biocrust ecology at short ranges (e.g., processing of complex compounds for waste management and resource provisioning) and longer ranges (e.g., translocation of resources such as water and the fungal loop model). This research shows that fungi are likely to have a greater contribution to biocrust function and dryland ecology than has generally been recognised.
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Affiliation(s)
- David R. Elliott
- Environmental Sustainability Research Centre, University of Derby, Derby, United Kingdom
| | - Andrew D. Thomas
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Stephen R. Hoon
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - Robin Sen
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, United Kingdom
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Liu Y. Grazing rest during spring regreening period promotes the ecological restoration of degraded alpine meadow vegetation through enhanced plant photosynthesis and respiration. FRONTIERS IN PLANT SCIENCE 2022; 13:1008550. [PMID: 36262656 PMCID: PMC9574263 DOI: 10.3389/fpls.2022.1008550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Grazing rest during the spring regreening period is the most economical and feasible measure for the ecological restoration of degraded alpine meadows and has been widely popularized and applied in China. The aim of the present study was to undertake a comparative analysis of the effects of grazing rest on the ecological restoration of degraded alpine meadows by plant photosynthesis and respiration. Coverage, height, ground biomass, belowground biomass of degraded alpine meadow vegetation, net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 concentration, chlorophyll fluorescence parameters, relative chlorophyll content, respiration rate, metabolite content, leaf relative water content, and related mineral element content of the dominant grass Elymus nutans Griseb. were measured in degraded alpine grassland with different grazing rest years. The results show that grazing rest during the spring regreening period promoted the ecological restoration of degraded alpine meadows by enhancing the photosynthesis and respiration of the dominant grass E. nutans Griseb. Grazing rest enhanced photosynthesis in dominant grass by increasing metabolites related to the Calvin cycle, chlorophyll content, leaf relative water content, and related mineral element content. Grazing at rest enhanced the respiration of dominant grass by increasing metabolites related to the TCA cycle, leaf relative water content, and related mineral element content. This positive effect gradually became stable with increasing years of grazing rest. Our results provide a fundamental basis for the popularization and application of grazing rest during the spring regreening period on degraded Tibetan Plateau grasslands.
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Díaz-Martínez P, Panettieri M, García-Palacios P, Moreno E, Plaza C, Maestre FT. Biocrusts Modulate Climate Change Effects on Soil Organic Carbon Pools: Insights From a 9-Year Experiment. Ecosystems 2022; 26:585-596. [PMID: 37179798 PMCID: PMC10167156 DOI: 10.1007/s10021-022-00779-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 07/14/2022] [Indexed: 11/03/2022]
Abstract
Accumulating evidence suggests that warming associated with climate change is decreasing the total amount of soil organic carbon (SOC) in drylands, although scientific research has not given enough emphasis to particulate (POC) and mineral-associated organic carbon (MAOC) pools. Biocrusts are a major biotic feature of drylands and have large impacts on the C cycle, yet it is largely unknown whether they modulate the responses of POC and MAOC to climate change. Here, we assessed the effects of simulated climate change (control, reduced rainfall (RE), warming (WA), and RE + WA) and initial biocrust cover (low (< 20%) versus high (> 50%)) on the mineral protection of soil C and soil organic matter quality in a dryland ecosystem in central Spain for 9 years. At low initial biocrust cover levels, both WA and RE + WA increased SOC, especially POC but also MAOC, and promoted a higher contribution of carbohydrates, relative to aromatic compounds, to the POC fraction. These results suggest that the accumulation of soil C under warming treatments may be transitory in soils with low initial biocrust cover. In soils with high initial biocrust cover, climate change treatments did not affect SOC, neither POC nor MAOC fraction. Overall, our results indicate that biocrust communities modulate the negative effect of climate change on SOC, because no losses of soil C were observed with the climate manipulations under biocrusts. Future work should focus on determining the long-term persistence of the observed buffering effect by biocrust-forming lichens, as they are known to be negatively affected by warming. Supplementary Information The online version contains supplementary material available at 10.1007/s10021-022-00779-0.
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Affiliation(s)
- Paloma Díaz-Martínez
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, 28933 Madrid, Spain
- Instituto de Ciencias Agrarias (ICA), CSIC, Serrano 115 bis, 28006 Madrid, Spain
| | - Marco Panettieri
- Instituto de Ciencias Agrarias (ICA), CSIC, Serrano 115 bis, 28006 Madrid, Spain
| | | | - Eduardo Moreno
- Departamento de Química Agrícola y Bromatología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - César Plaza
- Instituto de Ciencias Agrarias (ICA), CSIC, Serrano 115 bis, 28006 Madrid, Spain
| | - Fernando T. Maestre
- Instituto Multidisciplinar Para el Estudio del Medio “Ramón Margalef”, Universidad de Alicante, Alicante, Spain
- Departamento de Ecología, Universidad de Alicante, Alicante, Spain
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Oliveira MF, Maciel-Silva AS. Biological soil crusts and how they might colonize other worlds: insights from these Brazilian ecosystem engineers. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4362-4379. [PMID: 35522077 DOI: 10.1093/jxb/erac162] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 04/17/2022] [Indexed: 06/14/2023]
Abstract
When bryophytes, lichens, eukaryotic algae, cyanobacteria, bacteria, and fungi live interacting intimately with the most superficial particles of the soil, they form a complex community of organisms called the biological soil crust (BSC or biocrust). These biocrusts occur predominantly in drylands, where they provide important ecological services such as soil aggregation, moisture retention, and nitrogen fixation. Unfortunately, many BSC communities remain poorly explored, especially in the tropics. This review summarizes studies about BSCs in Brazil, a tropical megadiverse country, and shows the importance of ecological, physiological, and taxonomic knowledge of biocrusts. We also compare Brazilian BSC communities with others around the world, describe why BSCs can be considered ecosystem engineers, and propose their use in the colonization of other worlds.
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Affiliation(s)
- Mateus Fernandes Oliveira
- Universidade Federal de Minas Gerais, Laboratório de Sistemática Vegetal, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Adaíses Simone Maciel-Silva
- Universidade Federal de Minas Gerais, Laboratório de Sistemática Vegetal, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil
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Betemariyam M, Kefalew T. Carbon stock estimation of mixed-age date palm ( Phoenix dactylifera L.) farms in northeastern Ethiopia. Heliyon 2022; 8:e08844. [PMID: 35128115 PMCID: PMC8810365 DOI: 10.1016/j.heliyon.2022.e08844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/02/2021] [Accepted: 01/24/2022] [Indexed: 11/28/2022] Open
Abstract
The date palm (Phoenix dactylifera) is a fruit tree that grows from 392 to 1500 m above sea level. In addition to their socioeconomic, traditional, and religious value, it is a tree that tolerates high temperatures, drought, and salinity better than many other fruit crop plant species and plays an important role in the balancing and sequestration of atmospheric carbon. Date palm has been cultivated by agro pastoralists in Northeastern Ethiopia since ancient times, but no research has been done on the carbon stock of date palm farms (DPF) in the region. Therefore, the focus of the current study was to examine the carbon storage capacity in the biomass and soil of a DPF in the Aysaita and Afambo Districts of Northeastern Ethiopia. The ages of recorded date palm on the plot were classified into three age classes using information collected from the farm owners: 1st age class (for plantations less than 10 years), 2nd age class (for plantations between 10 and 20 years), and 3rd age class (for plantations older than 20 years). In the DPF, 45 main plots (20 m × 20 m) were established for tree species inventory. In the main plots, three 1 m × 1 m subplots were set up to collect soil samples. A total of 360 soil samples were collected; 180 for soil organic carbon fraction analysis and 180 for bulk density determination. The total carbon stock was calculated by adding the carbon stocks in biomass and soil (0–60 cm depth). Date palm trees accounted for 98.79% of total biomass carbon stocks in the date palm farm. The average aboveground biomass carbon stock of date palm trees older than 20 years was 1.55 and 1.36 times higher than the first and second age classes, respectively. Date palm trees between the ages of 5 and 20 years contributed 69.45% of total biomass carbon stocks (Mg C ha−1). Soil organic carbon made for 32.9% of total carbon stocks. Our research found that the date palm farm of this study would contribute to emission reduction and carbon sink enhancement, as well as improving local livelihoods in the study area. The highest numbers of date palm trees were found in the 10–20 age class among the available date palms. Date palm trees older than 20 years had a mean aboveground biomass carbon stock of 159.50 kg/plant. The SOC was accounted for 32.9% of total carbon stocks. The total carbon stock of the DPF was 82.3 Mg C ha−1.
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Yuan H, Matthew C, He XZ, Sun Y, Liu Y, Zhang T, Gao X, Yan C, Chang S, Hou F. Seasonal Variation in Soil and Herbage CO 2 Efflux for a Sheep-Grazed Alpine Meadow on the North-East Qinghai-Tibetan Plateau and Estimated Net Annual CO 2 Exchange. FRONTIERS IN PLANT SCIENCE 2022; 13:860739. [PMID: 35720569 PMCID: PMC9201780 DOI: 10.3389/fpls.2022.860739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 04/06/2022] [Indexed: 05/03/2023]
Abstract
The Qinghai-Tibetan Plateau is a vast geographic area currently subject to climate warming. Improved knowledge of the CO2 respiration dynamics of the Plateau alpine meadows and of the impact of grazing on CO2 fluxes is highly desirable. Such information will assist land use planning. We measured soil and vegetation CO2 efflux of alpine meadows using a closed chamber technique over diurnal cycles in winter, spring and summer. The annual, combined soil and plant respiration on ungrazed plots was 28.0 t CO2 ha-1 a-1, of which 3.7 t ha-1 a-1occurred in winter, when plant respiration was undetectable. This suggests winter respiration was driven mainly by microbial oxidation of soil organic matter. The winter respiration observed in this study was sufficient to offset the growing season CO2 sink reported for similar alpine meadows in other studies. Grazing increased herbage respiration in summer, presumably through stimulation of gross photosynthesis. From limited herbage production data, we estimate the sustainable yield of these meadows for grazing purposes to be about 500 kg herbage dry matter ha-1 a-1. Addition of photosynthesis data and understanding of factors affecting soil carbon sequestration to more precisely determine the CO2 balance of these grasslands is recommended.
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Affiliation(s)
- Hang Yuan
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Cory Matthew
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Xiong Zhao He
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Yi Sun
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Yang Liu
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Tao Zhang
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Xiaoye Gao
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Caiyu Yan
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Shenghua Chang
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Fujiang Hou
- Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
- *Correspondence: Fujiang Hou,
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Lan S, Thomas AD, Rakes JB, Garcia-Pichel F, Wu L, Hu C. Cyanobacterial community composition and their functional shifts associated with biocrust succession in the Gurbantunggut Desert. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:884-898. [PMID: 34533274 DOI: 10.1111/1758-2229.13011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/04/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacteria, as key biocrust components, provide a variety of ecosystem functions in drylands. In this study, to identify whether a cyanobacterial community shift is involved in biocrust succession and whether this is linked to altered ecological functions, we investigated cyanobacterial composition, total carbon and nitrogen contents of biocrusts in the Gurbantunggut Desert. Our findings showed that the biocrust cyanobacteria in the Gurbantunggut desert were mostly filamentous, coexisting with abundant unicellular colonial Chroococcidiopsis. Heterocystous Nostoc, Scytonema and Tolypothrix always represented the majority of biocrust nitrogen-fixing organisms, comprising an average of 92% of the nifH gene reads. Community analysis showed a clear shift in prokaryotic community composition associated with biocrust succession from cyanobacteria- to lichen- and moss-dominated biocrusts, and filamentous non-nitrogen-fixing cyanobacteria-dominated communities were gradually replaced by nitrogen-fixing and unicellular colonial communities. Along the succession, there were concomitant reductions in cyanobacterial relative abundance, whereas Chl-a, total carbon and nitrogen contents increased. Concurrently, distinct carbon and nitrogen stores shifts occurred, implying that the main ecological contribution of cyanobacteria in biocrusts changes from carbon- to nitrogen-fixation along with the succession. Our results suggest that any activity that reverses biocrust succession will influence cyanobacterial community composition and eventually lead to large reductions in soil carbon and nitrogen stores.
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Affiliation(s)
- Shubin Lan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Andrew David Thomas
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK
| | - Julie Bethany Rakes
- School of Life Sciences and Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, 85287, USA
| | - Ferran Garcia-Pichel
- School of Life Sciences and Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, 85287, USA
| | - Li Wu
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430072, China
| | - Chunxiang Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
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8
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Lan S, Thomas AD, Tooth S, Wu L, Elliott DR. Effects of vegetation on bacterial communities, carbon and nitrogen in dryland soil surfaces: implications for shrub encroachment in the southwest Kalahari. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:142847. [PMID: 33129532 DOI: 10.1016/j.scitotenv.2020.142847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 10/02/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
Shrub encroachment is occurring in many of the world's drylands, but its impacts on ecosystem structure and function are still poorly understood. In particular, it remains unclear how shrub encroachment affects dryland soil surfaces, including biological soil crust (biocrust) communities. In this study, soil surfaces (0-1 cm depth) were sampled from areas of Grewia flava shrubs and Eragrostis lehmanniana and Schmidtia kalahariensis grasses in the southwest Kalahari during two different seasons (March and November). Our hypothesis is that the presence of different vegetation cover types (shrubs versus grasses) alters the microbial composition of soil surfaces owing to their contrasting microenvironments. The results showed that more significant differences in microclimate (light, soil surface temperatures) and soil surface microbial communities were observed between shrubs and grasses than between sampling seasons. Based on high-throughput 16S rRNA gene sequencing, our findings showed that approximately one third (33.5%) of the operational taxonomic units (OTUs) occurred exclusively in soil surfaces beneath shrubs. Soil surfaces with biocrusts in grass areas were dominated by the cyanobacteria Microcoleus steenstrupii, whereas the soil surfaces beneath shrubs were dominated by the proteobacteria Microvirga flocculans. Soil surfaces beneath shrubs are associated with reduced cyanobacterial abundance but have higher total carbon and total nitrogen contents compared to biocrusts in grass areas. These findings infer changes in the relative contributions from different sources of carbon and nitrogen (e.g. cyanobacterial and non-cyanobacterial fixation, plant litter, animal activity). The distinctive microbial composition and higher carbon and nitrogen contents in soil surfaces beneath shrubs may provide a positive feedback mechanism promoting shrub encroachment, which helps to explain why the phenomenon is commonly observed to be irreversible.
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Affiliation(s)
- Shubin Lan
- Earth Surface Processes Research Group, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK; Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Andrew D Thomas
- Earth Surface Processes Research Group, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK
| | - Stephen Tooth
- Earth Surface Processes Research Group, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK
| | - Li Wu
- Earth Surface Processes Research Group, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430072, China
| | - David R Elliott
- Environmental Sustainability Research Centre, University of Derby, Derby, UK
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Berdugo M, Mendoza-Aguilar DO, Rey A, Ochoa V, Gozalo B, García-Huss L, Maestre FT. Litter Decomposition Rates of Biocrust-Forming Lichens Are Similar to Those of Vascular Plants and Are Affected by Warming. Ecosystems 2021. [DOI: 10.1007/s10021-020-00599-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Szyja M, Menezes AGDS, Oliveira FDA, Leal I, Tabarelli M, Büdel B, Wirth R. Neglected but Potent Dry Forest Players: Ecological Role and Ecosystem Service Provision of Biological Soil Crusts in the Human-Modified Caatinga. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00482] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Tibetan sheep grazing modifies rodent density and their interactions effect on GHG emissions of alpine meadow. Sci Rep 2019; 9:17066. [PMID: 31745148 PMCID: PMC6863865 DOI: 10.1038/s41598-019-53480-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/01/2019] [Indexed: 12/01/2022] Open
Abstract
Digging and mound-building by rodents lead to considerable disturbances in the topsoil and may affect plant composition, soil properties. However, little is known about the effects of these activities on GHG emissions, especially under different grazing management. This paper aimed to measure changes in CO2 and CH4 efflux with varying grazing management during the warm and cold seasons and to relate CO2 and CH4 efflux to pika burrow density and zokor mound density with different grazing management. Results of this study showed that CO2 efflux was significantly affected by the grazing season, whereas CH4 efflux was significantly affected by the grazing system. There were significant relationships between GHG efflux and rodent population density which were regulated by grazing management. CO2 efflux increased linearly with rodent density under seasonal continuous grazing in warm season. CO2 and CH4 efflux and rodent population density showed a significant quadratic convex relationship under rotational grazing at 24 SM/ha in warm and cold seasons and rotational grazing at 48 SM/ha in cold season. Under rotational grazing at light stocking rate (24 SM/ha), appropriate populations of rodents were beneficial for decreasing GHG emissions. This results also used to help drive a best-practices model for grazing practices of local herders.
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Lan S, Thomas AD, Tooth S, Wu L, Hu C. Small-Scale Spatial Heterogeneity of Photosynthetic Fluorescence Associated with Biological Soil Crust Succession in the Tengger Desert, China. MICROBIAL ECOLOGY 2019; 78:936-948. [PMID: 30949750 DOI: 10.1007/s00248-019-01356-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/06/2019] [Indexed: 06/09/2023]
Abstract
In dryland regions, biological soil crusts (BSCs) have numerous important ecosystem functions. Crust species and functions are, however, highly spatially heterogeneous and remain poorly understood at a range of scales. In this study, chlorophyll fluorescence imaging was used to quantify millimeter-scale patterns in the distribution and activity of photosynthetic organisms in BSCs of different successional stages (including cyanobacterial, lichen, moss three main successional stages and three intermixed transitional stages) from the Tengger Desert, China. Chlorophyll fluorescence images derived from the Imaging PAM (Pulse Amplitude Modulation) showed that with the succession from cyanobacterial to lichen and to moss crusts, crust photosynthetic efficiency (including the maximum and effective photosynthetic efficiency, respectively) and fluorescence coverage increased significantly (P < 0.05), and that increasing photosynthetically active radiation (PAR) reduced the effective photosynthetic efficiency (Yield). The distribution of photosynthetic organisms in crusts determined Fv/Fm (ratio of variable fluorescence to maximum fluorescence) frequency pattern, although the photosynthetic heterogeneity (SHI index) was not significantly different (P > 0.05) between cyanobacterial and moss crusts, and showed a unimodal pattern of Fv/Fm values. In contrast, photosynthetic heterogeneity was significantly higher in lichen, cyanobacteria-moss and lichen-moss crusts (P < 0.05), with a bimodal pattern of Fv/Fm values. Point pattern analysis showed that the distribution pattern of chlorophyll fluorescence varied at different spatial scales and also among the different crust types. These new results provide a detailed (millimeter-scale) insight into crust photosynthetic mechanisms and spatial distribution patterns associated with their community types. Collectively, this information provides an improved theoretical basis for crust maintenance and management in dryland regions.
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Affiliation(s)
- Shubin Lan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK
| | - Andrew David Thomas
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK
| | - Stephen Tooth
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK
| | - Li Wu
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430072, China
| | - Chunxiang Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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An Assessment of Multiple Drivers Determining Woody Species Composition and Structure: A Case Study from the Kalahari, Botswana. LAND 2019. [DOI: 10.3390/land8080122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Savannas are extremely important socio-economic landscapes, with pastoralist societies relying on these ecosystems to sustain their livelihoods and economy. Globally, there is an increase of woody vegetation in these ecosystems, degrading the potential of these multi-functional landscapes to sustain societies and wildlife. Several mechanisms have been invoked to explain the processes responsible for woody vegetation composition; however, these are often investigated separately at scales not best suited to land-managers, thereby impeding the evaluation of their relative importance. We ran six transects at 15 sites along the Kalahari transect, collecting data on species identity, diversity, and abundance. We used Poisson and Tobit regression models to investigate the relationship among woody vegetation, precipitation, grazing, borehole density, and fire. We identified 44 species across 78 transects, with the highest species richness and abundance occurring at Kuke (middle of the rainfall gradient). Precipitation was the most important environmental variable across all species and various morphological groups, while increased borehole density and livestock resulted in lower bipinnate species abundance, contradicting the consensus that these managed features increase the presence of such species. Rotating cattle between boreholes subsequently reduces the impact of trampling and grazing on the soil and maintains and/or reduces woody vegetation abundance.
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14
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Habitat-dependent composition of bacterial and fungal communities in biological soil crusts from Oman. Sci Rep 2019; 9:6468. [PMID: 31015576 PMCID: PMC6478931 DOI: 10.1038/s41598-019-42911-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 04/09/2019] [Indexed: 11/08/2022] Open
Abstract
Biological soil crusts (biocrusts) occur within drylands throughout the world, covering ~12% of the global terrestrial soil surface. Their occurrence in the deserts of the Arabian Peninsula has rarely been reported and their spatial distribution, diversity, and microbial composition remained largely unexplored. We investigated biocrusts at six different locations in the coastal and central deserts of Oman. The biocrust types were characterized, and the bacterial and fungal community compositions of biocrusts and uncrusted soils were analysed by amplicon sequencing. The results were interpreted based on the environmental parameters of the different sites. Whereas at lowland sites, mainly cyanobacteria-dominated biocrusts were observed, both cyanobacteria- and lichen-dominated biocrusts occurred at mountain sites. The majority of bacterial sequences (32–83% of total sequences) belonged to Actinobacteria, Cyanobacteria, Alphaproteobacteria, and Bacteroidetes, whereas fungal sequences belonged to Ascomycota, Basidiomycota, and Chytridiomycota (>95%). With biocrust development, a notable increase in cyanobacterial and decrease in actinobacterial proportions was observed for cyanobacteria-dominated crusts. In coastal areas, where salinity is high, biocrusts were replaced by a unique marine mat-like microbial community, dominated by halotolerant taxa. Redundancy analysis revealed a significant contribution of soil texture, cover type, carbon content, and elevation to the variations in bacterial and fungal communities. Multivariate analysis placed microbial communities in significantly separated clusters based on their carbon content, elevation and electrical conductivity. We conclude that Oman hosts a variety of cyanobacteria- and lichen-dominated crusts with their bacterial and fungal communities being largely dictated by soil properties and environmental parameters.
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García-Palacios P, Escolar C, Dacal M, Delgado-Baquerizo M, Gozalo B, Ochoa V, Maestre FT. Pathways regulating decreased soil respiration with warming in a biocrust-dominated dryland. GLOBAL CHANGE BIOLOGY 2018; 24:4645-4656. [PMID: 30007104 DOI: 10.1111/gcb.14399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/17/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
A positive soil carbon (C)-climate feedback is embedded into the climatic models of the IPCC. However, recent global syntheses indicate that the temperature sensitivity of soil respiration (RS ) in drylands, the largest biome on Earth, is actually lower in warmed than in control plots. Consequently, soil C losses with future warming are expected to be low compared with other biomes. Nevertheless, the empirical basis for these global extrapolations is still poor in drylands, due to the low number of field experiments testing the pathways behind the long-term responses of soil respiration (RS ) to warming. Importantly, global drylands are covered with biocrusts (communities formed by bryophytes, lichens, cyanobacteria, fungi, and bacteria), and thus, RS responses to warming may be driven by both autotrophic and heterotrophic pathways. Here, we evaluated the effects of 8-year experimental warming on RS , and the different pathways involved, in a biocrust-dominated dryland in southern Spain. We also assessed the overall impacts on soil organic C (SOC) accumulation over time. Across the years and biocrust cover levels, warming reduced RS by 0.30 μmol CO2 m-2 s-1 (95% CI = -0.24 to 0.84), although the negative warming effects were only significant after 3 years of elevated temperatures in areas with low initial biocrust cover. We found support for different pathways regulating the warming-induced reduction in RS at areas with low (microbial thermal acclimation via reduced soil mass-specific respiration and β-glucosidase enzymatic activity) vs. high (microbial thermal acclimation jointly with a reduction in autotrophic respiration from decreased lichen cover) initial biocrust cover. Our 8-year experimental study shows a reduction in soil respiration with warming and highlights that biocrusts should be explicitly included in modeling efforts aimed to quantify the soil C-climate feedback in drylands.
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Affiliation(s)
- Pablo García-Palacios
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Cristina Escolar
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Marina Dacal
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Manuel Delgado-Baquerizo
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado
| | - Beatriz Gozalo
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Victoria Ochoa
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Fernando T Maestre
- Departamento de Biología y Geología, Física y Química Inorgánica y Analítica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain
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Renuka N, Guldhe A, Prasanna R, Singh P, Bux F. Microalgae as multi-functional options in modern agriculture: current trends, prospects and challenges. Biotechnol Adv 2018; 36:1255-1273. [DOI: 10.1016/j.biotechadv.2018.04.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 02/09/2018] [Accepted: 04/13/2018] [Indexed: 10/17/2022]
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Abdalla M, Hastings A, Chadwick D, Jones D, Evans C, Jones M, Rees R, Smith P. Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands. AGRICULTURE, ECOSYSTEMS & ENVIRONMENT 2018; 253:62-81. [PMID: 29398743 PMCID: PMC5727677 DOI: 10.1016/j.agee.2017.10.023] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Livestock grazing intensity (GI) is thought to have a major impact on soil organic carbon (SOC) storage and soil quality indicators in grassland agroecosystems. To critically investigate this, we conducted a global review and meta-analysis of 83 studies of extensive grazing, covering 164 sites across different countries and climatic zones. Unlike previous published reviews we normalized the SOC and total nitrogen (TN) data to a 30 cm depth to be compatible with IPCC guidelines. We also calculated a normalized GI and divided the data into four main groups depending on the regional climate (dry warm, DW; dry cool, DC; moist warm, MW; moist cool, MC). Our results show that taken across all climatic zones and GIs, grazing (below the carrying capacity of the systems) results in a decrease in SOC storage, although its impact on SOC is climate-dependent. When assessed for different regional climates, all GI levels increased SOC stocks under the MW climate (+7.6%) whilst there were reductions under the MC climate (-19%). Under the DW and DC climates, only the low (+5.8%) and low to medium (+16.1%) grazing intensities, respectively, were associated with increased SOC stocks. High GI significantly increased SOC for C4-dominated grassland compared to C3-dominated grassland and C3-C4 mixed grasslands. It was also associated with significant increases in TN and bulk density but had no effect on soil pH. To protect grassland soils from degradation, we recommend that GI and management practices should be optimized according to climate region and grassland type (C3, C4 or C3-C4 mixed).
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Affiliation(s)
- M. Abdalla
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
- Corresponding author at: Institute of Biological and Environmental Sciences, School of Biological, Sciences, University of Aberdeen, 23 St. Machar Drive, Aberdeen, AB24 3UU, UK.Institute of Biological and Environmental SciencesSchool of Biological SciencesUniversity of AberdeenAberdeenAB24 3UUUK
| | - A. Hastings
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
| | - D.R. Chadwick
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - D.L. Jones
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - C.D. Evans
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - M.B. Jones
- Department of Botany, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
| | - R.M. Rees
- Scotland’s Rural College (SRUC) Edinburgh, West Mains Road, Edinburgh, EH93JG, UK
| | - P. Smith
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
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Velasco Ayuso S, Giraldo Silva A, Nelson C, Barger NN, Garcia-Pichel F. Microbial Nursery Production of High-Quality Biological Soil Crust Biomass for Restoration of Degraded Dryland Soils. Appl Environ Microbiol 2017; 83:e02179-16. [PMID: 27864178 PMCID: PMC5244311 DOI: 10.1128/aem.02179-16] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/15/2016] [Indexed: 11/20/2022] Open
Abstract
Biological soil crusts (biocrusts) are slow-growing, phototroph-based microbial assemblages that develop on the topsoils of drylands. Biocrusts help maintain soil fertility and reduce erosion. Because their loss through human activities has negative ecological and environmental health consequences, biocrust restoration is of interest. Active soil inoculation with biocrust microorganisms can be an important tool in this endeavor. We present a culture-independent, two-step process to grow multispecies biocrusts in open greenhouse nursery facilities, based on the inoculation of local soils with local biocrust remnants and incubation under seminatural conditions that maintain the essence of the habitat but lessen its harshness. In each of four U.S. Southwest sites, we tested and deployed combinations of factors that maximized growth (gauged as chlorophyll a content) while minimizing microbial community shifts (assessed by 16S rRNA sequencing and bioinformatics), particularly for crust-forming cyanobacteria. Generally, doubling the frequency of natural wetting events, a 60% reduction in sunlight, and inoculation by slurry were optimal. Nutrient addition effects were site specific. In 4 months, our approach yielded crusts of high inoculum quality reared on local soil exposed to locally matched climates, acclimated to desiccation, and containing communities minimally shifted in composition from local ones. Our inoculum contained abundant crust-forming cyanobacteria and no significant numbers of allochthonous phototrophs, and it was sufficient to treat ca. 6,000 m2 of degraded dryland soils at 1 to 5% of the typical crust biomass concentration, having started from a natural crust remnant as small as 6 to 30 cm2 IMPORTANCE: Soil surface crusts can protect dryland soils from erosion, but they are often negatively impacted by human activities. Their degradation causes a loss of fertility, increased production of fugitive dust and intensity of dust storms with associated traffic problems, and provokes general public health hazards. Our results constitute an advance in the quest to actively restore biological soil covers by providing a means to obtain high-quality inoculum within a reasonable time (a few months), thereby allowing land managers to recover essential, but damaged, ecosystem services in a sustainable, self-perpetuating way as provided by biocrust communities.
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Affiliation(s)
| | - Ana Giraldo Silva
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Corey Nelson
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Nichole N Barger
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Ferran Garcia-Pichel
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
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Ogura T, Date Y, Masukujane M, Coetzee T, Akashi K, Kikuchi J. Improvement of physical, chemical, and biological properties of aridisol from Botswana by the incorporation of torrefied biomass. Sci Rep 2016; 6:28011. [PMID: 27313139 PMCID: PMC4911548 DOI: 10.1038/srep28011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/14/2016] [Indexed: 01/14/2023] Open
Abstract
Effective use of agricultural residual biomass may be beneficial for both local and global ecosystems. Recently, biochar has received attention as a soil enhancer, and its effects on plant growth and soil microbiota have been investigated. However, there is little information on how the physical, chemical, and biological properties of soil amended with biochar are affected. In this study, we evaluated the effects of the incorporation of torrefied plant biomass on physical and structural properties, elemental profiles, initial plant growth, and metabolic and microbial dynamics in aridisol from Botswana. Hemicellulose in the biomass was degraded while cellulose and lignin were not, owing to the relatively low-temperature treatment in the torrefaction preparation. Water retentivity and mineral availability for plants were improved in soils with torrefied biomass. Furthermore, fertilization with 3% and 5% of torrefied biomass enhanced initial plant growth and elemental uptake. Although the metabolic and microbial dynamics of the control soil were dominantly associated with a C1 metabolism, those of the 3% and 5% torrefied biomass soils were dominantly associated with an organic acid metabolism. Torrefied biomass was shown to be an effective soil amendment by enhancing water retentivity, structural stability, and plant growth and controlling soil metabolites and microbiota.
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Affiliation(s)
- Tatsuki Ogura
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.,Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yasuhiro Date
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.,Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Masego Masukujane
- Department of Agricultural Research, Ministry of Agriculture, Private Bag 0033, Gaborone, Botswana
| | - Tidimalo Coetzee
- Department of Agricultural Research, Ministry of Agriculture, Private Bag 0033, Gaborone, Botswana
| | - Kinya Akashi
- Faculty of Agriculture, Tottori University, 4-101 Koyama-cho, Tottori 680-8533, Japan
| | - Jun Kikuchi
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.,Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.,Graduate School of Bioagricultural Sciences, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya 464-0810, Japan
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Makhalanyane TP, Valverde A, Gunnigle E, Frossard A, Ramond JB, Cowan DA. Microbial ecology of hot desert edaphic systems. FEMS Microbiol Rev 2015; 39:203-21. [DOI: 10.1093/femsre/fuu011] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Escolar C, Maestre FT, Rey A. Biocrusts modulate warming and rainfall exclusion effects on soil respiration in a semi-arid grassland. SOIL BIOLOGY & BIOCHEMISTRY 2015; 80:9-17. [PMID: 25914428 PMCID: PMC4405768 DOI: 10.1016/j.soilbio.2014.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Soil surface communities composed of cyanobacteria, algae, mosses, liverworts, fungi, bacteria and lichens (biocrusts) largely affect soil respiration in dryland ecosystems. Climate change is expected to have large effects on biocrusts and associated ecosystem processes. However, few studies so far have experimentally assessed how expected changes in temperature and rainfall will affect soil respiration in biocrust-dominated ecosystems. We evaluated the impacts of biocrust development, increased air temperature and decreased precipitation on soil respiration dynamics during dry (2009) and wet (2010) years, and investigated the relative importance of soil temperature and moisture as environmental drivers of soil respiration, in a semiarid grassland from central Spain. Soil respiration rates were significantly lower in the dry than during the wet year, regardless of biocrust cover. Warming increased soil respiration rates, but this response was only significant in biocrust-dominated areas (> 50% biocrust cover). Warming also increased the temperature sensitivity (Q10 values) of soil respiration in biocrust-dominated areas, particularly during the wet year. The combination of warming and rainfall exclusion had similar effects in low biocrust cover areas. Our results highlight the importance of biocrusts as a modulator of soil respiration responses to both warming and rainfall exclusion, and indicate that they must be explicitly considered when evaluating soil respiration responses to climate change in drylands.
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Affiliation(s)
- Cristina Escolar
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, E-28933 Móstoles, Spain
| | - Fernando T. Maestre
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, E-28933 Móstoles, Spain
| | - Ana Rey
- Department of Biogeography and Global Change, Museo de Ciencias Naturales, C.S.I.C., Serrano 115, 28006 Madrid, Spain
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Briske DD, Bestelmeyer BT, Brown JR. Savory's Unsubstantiated Claims Should Not Be Confused With Multipaddock Grazing. ACTA ACUST UNITED AC 2014. [DOI: 10.2111/1551-501x-36.1.39] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Maestre FT, Escolar C, de Guevara ML, Quero JL, Lázaro R, Delgado-Baquerizo M, Ochoa V, Berdugo M, Gozalo B, Gallardo A. Changes in biocrust cover drive carbon cycle responses to climate change in drylands. GLOBAL CHANGE BIOLOGY 2013; 19:3835-47. [PMID: 23818331 PMCID: PMC3942145 DOI: 10.1111/gcb.12306] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 06/06/2013] [Indexed: 05/24/2023]
Abstract
Dryland ecosystems account for ca. 27% of global soil organic carbon (C) reserves, yet it is largely unknown how climate change will impact C cycling and storage in these areas. In drylands, soil C concentrates at the surface, making it particularly sensitive to the activity of organisms inhabiting the soil uppermost levels, such as communities dominated by lichens, mosses, bacteria and fungi (biocrusts). We conducted a full factorial warming and rainfall exclusion experiment at two semiarid sites in Spain to show how an average increase of air temperature of 2-3 °C promoted a drastic reduction in biocrust cover (ca. 44% in 4 years). Warming significantly increased soil CO2 efflux, and reduced soil net CO2 uptake, in biocrust-dominated microsites. Losses of biocrust cover with warming through time were paralleled by increases in recalcitrant C sources, such as aromatic compounds, and in the abundance of fungi relative to bacteria. The dramatic reduction in biocrust cover with warming will lessen the capacity of drylands to sequester atmospheric CO2 . This decrease may act synergistically with other warming-induced effects, such as the increase in soil CO2 efflux and the changes in microbial communities to alter C cycling in drylands, and to reduce soil C stocks in the mid to long term.
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Affiliation(s)
- Fernando T. Maestre
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/Tulipán s/n, 28933 Móstoles, Spain
| | - Cristina Escolar
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/Tulipán s/n, 28933 Móstoles, Spain
| | - Mónica Ladrón de Guevara
- Estación Experimental de Zonas Áridas (CSIC), Carretera de Sacramento, s/n, 04120 La Cañada de San Urbano-Almería, Spain
| | - José L. Quero
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/Tulipán s/n, 28933 Móstoles, Spain
- Departamento de Ingeniería Forestal, Escuela Técnica Superior de Ingeniería Agronómica y de Montes, Universidad de Córdoba, Campus de Rabanales, Crta. N-IV km. 396, 14071 Córdoba, Spain
| | - Roberto Lázaro
- Estación Experimental de Zonas Áridas (CSIC), Carretera de Sacramento, s/n, 04120 La Cañada de San Urbano-Almería, Spain
| | - Manuel Delgado-Baquerizo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Sevilla, Spain
| | - Victoria Ochoa
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/Tulipán s/n, 28933 Móstoles, Spain
| | - Miguel Berdugo
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/Tulipán s/n, 28933 Móstoles, Spain
| | - Beatriz Gozalo
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/Tulipán s/n, 28933 Móstoles, Spain
| | - Antonio Gallardo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Sevilla, Spain
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Briske DD, Bestelmeyer BT, Brown JR, Fuhlendorf SD, Wayne Polley H. The Savory Method Can Not Green Deserts or Reverse Climate Change. ACTA ACUST UNITED AC 2013. [DOI: 10.2111/rangelands-d-13-00044.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Escolar C, Martínez I, Bowker MA, Maestre FT. Warming reduces the growth and diversity of biological soil crusts in a semi-arid environment: implications for ecosystem structure and functioning. Philos Trans R Soc Lond B Biol Sci 2013; 367:3087-99. [PMID: 23045707 DOI: 10.1098/rstb.2011.0344] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Biological soil crusts (BSCs) are key biotic components of dryland ecosystems worldwide that control many functional processes, including carbon and nitrogen cycling, soil stabilization and infiltration. Regardless of their ecological importance and prevalence in drylands, very few studies have explicitly evaluated how climate change will affect the structure and composition of BSCs, and the functioning of their constituents. Using a manipulative experiment conducted over 3 years in a semi-arid site from central Spain, we evaluated how the composition, structure and performance of lichen-dominated BSCs respond to a 2.4°C increase in temperature, and to an approximately 30 per cent reduction of total annual rainfall. In areas with well-developed BSCs, warming promoted a significant decrease in the richness and diversity of the whole BSC community. This was accompanied by important compositional changes, as the cover of lichens suffered a substantial decrease with warming (from 70 to 40% on average), while that of mosses increased slightly (from 0.3 to 7% on average). The physiological performance of the BSC community, evaluated using chlorophyll fluorescence, increased with warming during the first year of the experiment, but did not respond to rainfall reduction. Our results indicate that ongoing climate change will strongly affect the diversity and composition of BSC communities, as well as their recovery after disturbances. The expected changes in richness and composition under warming could reduce or even reverse the positive effects of BSCs on important soil processes. Thus, these changes are likely to promote an overall reduction in ecosystem processes that sustain and control nutrient cycling, soil stabilization and water dynamics.
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Affiliation(s)
- Cristina Escolar
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles 28933, Spain.
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Dougill AJ, Stringer LC, Leventon J, Riddell M, Rueff H, Spracklen DV, Butt E. Lessons from community-based payment for ecosystem service schemes: from forests to rangelands. Philos Trans R Soc Lond B Biol Sci 2013; 367:3178-90. [PMID: 23045714 DOI: 10.1098/rstb.2011.0418] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Climate finance investments and international policy are driving new community-based projects incorporating payments for ecosystem services (PES) to simultaneously store carbon and generate livelihood benefits. Most community-based PES (CB-PES) research focuses on forest areas. Rangelands, which store globally significant quantities of carbon and support many of the world's poor, have seen little CB-PES research attention, despite benefitting from several decades of community-based natural resource management (CBNRM) projects. Lessons from CBNRM suggest institutional considerations are vital in underpinning the design and implementation of successful community projects. This study uses documentary analysis to explore the institutional characteristics of three African community-based forest projects that seek to deliver carbon-storage and poverty-reduction benefits. Strong existing local institutions, clear land tenure, community control over land management decision-making and up-front, flexible payment schemes are found to be vital. Additionally, we undertake a global review of rangeland CBNRM literature and identify that alongside the lessons learned from forest projects, rangeland CB-PES project design requires specific consideration of project boundaries, benefit distribution, capacity building for community monitoring of carbon storage together with awareness-raising using decision-support tools to display the benefits of carbon-friendly land management. We highlight that institutional analyses must be undertaken alongside improved scientific studies of the carbon cycle to enable links to payment schemes, and for them to contribute to poverty alleviation in rangelands.
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Affiliation(s)
- Andrew J Dougill
- School of Earth and Environment, University of Leeds, Leeds, UK.
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Maestre FT, Salguero-Gómez R, Quero JL. It is getting hotter in here: determining and projecting the impacts of global environmental change on drylands. Philos Trans R Soc Lond B Biol Sci 2013; 367:3062-75. [PMID: 23045705 DOI: 10.1098/rstb.2011.0323] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drylands occupy large portions of the Earth, and are a key terrestrial biome from the socio-ecological point of view. In spite of their extent and importance, the impacts of global environmental change on them remain poorly understood. In this introduction, we review some of the main expected impacts of global change in drylands, quantify research efforts on the topic, and highlight how the articles included in this theme issue contribute to fill current gaps in our knowledge. Our literature analyses identify key under-studied areas that need more research (e.g. countries such as Mauritania, Mali, Burkina Faso, Chad and Somalia, and deserts such as the Thar, Kavir and Taklamakan), and indicate that most global change research carried out to date in drylands has been done on a unidisciplinary basis. The contributions included here use a wide array of organisms (from micro-organisms to humans), spatial scales (from local to global) and topics (from plant demography to poverty alleviation) to examine key issues to the socio-ecological impacts of global change in drylands. These papers highlight the complexities and difficulties associated with the prediction of such impacts. They also identify the increased use of long-term experiments and multidisciplinary approaches as priority areas for future dryland research. Major advances in our ability to predict and understand global change impacts on drylands can be achieved by explicitly considering how the responses of individuals, populations and communities will in turn affect ecosystem services. Future research should explore linkages between these responses and their effects on water and climate, as well as the provisioning of services for human development and well-being.
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Affiliation(s)
- Fernando T Maestre
- Área de Biodiversidad y Conservación, Departamento de Biología y Geología, ESCET, Universidad Rey Juan Carlos, 28933 Móstoles, Spain.
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