Biological Soil Crust Microsites Are the Main Contributor to Soil Respiration in a Semiarid Ecosystem

Biological soil crusts (BSCs) are a key biotic component of dryland ecosystems worldwide. However, most studies carried out to date on carbon (C) fluxes in these ecosystems, such as soil respiration, have neglected them. We conducted a 3.5-year field experiment to evaluate the spatio-temporal hetero...

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Bibliographic Details
Published in:Ecosystems (New York) 2011-08, Vol.14 (5), p.835-847
Main Authors: Castillo-Monroy, Andrea P., Maestre, Fernando T., Rey, Ana, Soliveres, Santiago, García-Palacios, Pablo
Format: Article
Language:English
Subjects:
Analysis
Animal and plant ecology
Animal, plant and microbial ecology
Arid zones
Biogeochemistry
Biological and medical sciences
Biological soil crusts
Biomedical and Life Sciences
Climate change
Climatology. Bioclimatology. Climate change
Desert soils
Earth, ocean, space
Ecology
Ecosystem components
Ecosystems
Environmental Management
Exact sciences and technology
External geophysics
Fundamental and applied biological sciences. Psychology
General aspects
Geoecology/Natural Processes
Grassland soils
Hydrology/Water Resources
Life Sciences
Meteorology
Plant Sciences
Soil ecology
Soil moisture
Soil respiration
Soil temperature
Soil water
Soils
Synecology
Terrestrial ecosystems
Zoology
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Summary:Biological soil crusts (BSCs) are a key biotic component of dryland ecosystems worldwide. However, most studies carried out to date on carbon (C) fluxes in these ecosystems, such as soil respiration, have neglected them. We conducted a 3.5-year field experiment to evaluate the spatio-temporal heterogeneity of soil respiration in a semiarid Stipatenacissima steppe and to assess the contribution of BSC-dominated areas to the annual soil respiration of the whole ecosystem. We selected the six most frequent microsites in the study area: Stipa tussocks (ST), Retama sphaerocarpa shrubs (RS), and open areas with very low (< 5% BSC cover, BS), low, medium and high cover of well-developed BSCs. Soil respiration rates did not differ among BSCdominated microsites but were significantly higher and lower than those found in BS and ST microsites, respectively. A model using soil temperature and soil moisture accounted for over 85% of the temporal variation in soil respiration throughout the studied period. Using this model, we estimated a range of 240.4-322.6 g C m⁻² y⁻¹ released by soil respiration at our study area. Vegetated (ST and RS) and BSC-dominated microsites accounted for 37 and 42% of this amount, respectively. Our results indicate that accounting for the spatial heterogeneity in soil respiration induced by BSCs is crucial to provide accurate estimations of this flux at the ecosystem level. They also highlight that BSC-dominated areas are the main contributor to the total C released by soil respiration and, therefore, must be considered when estimating C budgets in drylands.
ISSN:1432-9840
1435-0629
DOI:10.1007/s10021-011-9449-3