Our findings indicate the importance of paleoclimatic information to improve quantitative predictions of global soil C stocks.
Microorganisms carrying pmoA and nosZ genes are major drivers of methane and nitrous oxide fluxes from soils. However, most studies on these organisms have been conducted in mesic ecosystems; therefore, little is known about the factors driving their distribution in drylands, the largest biome on Earth. We conducted a global survey to evaluate the role of climate\uffe2\uff80\uff90 and soil\uffe2\uff80\uff90related variables as predictors of the richness, abundance and community structure of bacteria carrying pmoA and nosZ genes.
LocationEighty dryland ecosystems distributed worldwide.
Time periodFrom February 2006 to December 2011.
Major taxa studiedMethanotrophic (carrying the pmoA gene) and denitrifiying (carrying the nosZ gene) bacteria.
MethodsWe used data from a field survey and structural equation modelling to evaluate the direct and indirect effects of climatic (aridity, rainfall seasonality and mean annual temperature) and soil (organic carbon, pH and texture) variables on the total abundance, richness and community structure of microorganisms carrying pmoA and nosZ genes.
ResultsTaxa related to Methylococcus capsulatus or Methylocapsa sp., often associated with mesic environments, were common in global drylands. The abundance and richness of methanotrophs were not associated with climate or soil properties. However, mean annual temperature, rainfall seasonality, organic C, pH and sand content were highly correlated with their community structure. Aridity and soil variables, such as sand content and pH, were correlated with the abundance, community structure and richness of the nosZ bacterial community.
Main conclusionsOur study provides new insights into the drivers of the abundance, richness and community structure of soil microorganisms carrying pmoA and nosZ genes in drylands worldwide. We highlight how ongoing climate change will alter the structure of soil microorganisms, which might affect the net CH4 exchange and will probably reduce the capacity of dryland soils to carry out the final step of denitrification, favouring net N2O emissions.Under controlled laboratory conditions, high and low ammonium availability are known to favor soil ammonia-oxidizing bacteria (AOB) and archaea (AOA) communities, respectively. However, whether this niche segregation is maintained under field conditions in terrestrial ecosystems remains unresolved, particularly at the global scale. We hypothesized that perennial vegetation might favor AOB vs. AOA communities compared with adjacent open areas devoid of perennial vegetation (i.e., bare soil) via several mechanisms, including increasing the amount of ammonium in soil. To test this niche-differentiation hypothesis, we conducted a global field survey including 80 drylands from 6 continents. Data supported our hypothesis, as soils collected under plant canopies had higher levels of ammonium, as well as higher richness (number of terminal restriction fragments; T-RFs) and abundance (qPCR amoA genes) of AOB, and lower richness and abundance of AOA, than those collected in open areas located between plant canopies. Some of the reported associations between plant canopies and AOA and AOB communities can be a consequence of the higher organic matter and available N contents found under plant canopies. Other aspects of soils associated with vegetation including shading and microclimatic conditions might also help explain our results. Our findings provide strong evidence for niche differentiation between AOA and AOB communities in drylands worldwide, advancing our understanding of their ecology and biogeography at the global scale.The relationship between soil microbial communities and the resistance of multiple ecosystem functions linked to C, N and P cycling (multifunctionality resistance) to global change has never been assessed globally in natural ecosystems. We collected soils from 59 dryland ecosystems worldwide to investigate the importance of microbial communities as predictor of multifunctionality resistance to climate change and nitrogen fertilisation. Multifunctionality had a lower resistance to wetting\uffe2\uff80\uff93drying cycles than to warming or N deposition. Multifunctionality resistance was regulated by changes in microbial composition (relative abundance of phylotypes) but not by richness, total abundance of fungi and bacteria or the fungal: bacterial ratio. Our results suggest that positive effects of particular microbial taxa on multifunctionality resistance could potentially be controlled by altering soil pH. Together, our work demonstrates strong links between microbial community composition and multifunctionality resistance in dryland soils from six continents, and provides insights into the importance of microbial community composition for buffering effects of global change in drylands worldwide.The global spread of woody plants into grasslands is predicted to increase over the coming century. While there is general agreement regarding the anthropogenic causes of this phenomenon, its ecological consequences are less certain. We analysed how woody vegetation of differing cover affects plant diversity (richness and evenness) and the surrogates of multiple ecosystem processes (multifunctionality) in global drylands, and how these change with aridity.
LocationTwo hundred and twenty\uffe2\uff80\uff90four dryland sites from all continents except Antarctica, widely differing in their environmental conditions (from arid to dry\uffe2\uff80\uff90subhumid sites) and relative woody cover (from 0 to 100%).
MethodsUsing a standardized field survey, we measured the cover, richness and evenness of perennial vegetation. At each site, we measured 14 soil variables related to fertility and the build\uffe2\uff80\uff90up of nutrient pools. These variables are critical for maintaining ecosystem functioning in drylands.
ResultsSpecies richness and ecosystem multifunctionality were strongly related to woody vegetation, with both variables peaking at a relative woody cover (RWC) of 41\uffe2\uff80\uff9360%. This relationship shifted with aridity. We observed linear positive effects of RWC in dry\uffe2\uff80\uff90subhumid sites. These positive trends shifted to hump\uffe2\uff80\uff90shaped RWC\uffe2\uff80\uff93diversity and multifunctionality relationships under semi\uffe2\uff80\uff90arid environments. Finally, hump\uffe2\uff80\uff90shaped (richness, evenness) or linear negative (multifunctionality) effects of RWC were found under the most arid conditions.
Main conclusionsPlant diversity and multifunctionality peaked at intermediate levels of woody cover, although this relationship became increasingly positive in wetter environments. This comprehensive study accounts for multiple ecosystem attributes across a range of levels of woody cover and environmental conditions. Our results help us to reconcile contrasting views of woody encroachment found in the current literature and can be used to improve predictions of the likely effects of encroachment on biodiversity and ecosystem services.
", "keywords": ["580", "0106 biological sciences", "2. Zero hunger", "arid regions", "species diversity", "vegetation dynamics", "Thicketization", "Shrub encroachment", "shrubland ecology", "Species evennes", "15. Life on land", "01 natural sciences", "Soil", "Semi-arid", "13. Climate action", "XXXXXX - Unknown", "soils", "Aridity", "Species richness"]}, "links": [{"href": "https://doi.org/10.1111/geb.12215"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Ecology%20and%20Biogeography", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/geb.12215", "name": "item", "description": "10.1111/geb.12215", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/geb.12215"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2014-09-13T00:00:00Z"}}, {"id": "10.1111/nph.15120", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-09-21T16:17:53Z", "type": "Journal Article", "created": "2018-04-02", "title": "Biocrust\u2010forming mosses mitigate the impact of aridity on soil microbial communities in drylands: observational evidence from three continents", "description": "Summary
Recent research indicates that increased aridity linked to climate change will reduce the diversity of soil microbial communities and shift their community composition in drylands, Earth's largest biome. However, we lack both a theoretical framework and solid empirical evidence of how important biotic components from drylands, such as biocrust\uffe2\uff80\uff90forming mosses, will regulate the responses of microbial communities to expected increases in aridity with climate change.
Here we report results from a cross\uffe2\uff80\uff90continental (North America, Europe and Australia) survey of 39 locations from arid to humid ecosystems, where we evaluated how biocrust\uffe2\uff80\uff90forming mosses regulate the relationship between aridity and the community composition and diversity of soil bacteria and fungi in dryland ecosystems.
Increasing aridity was negatively related to the richness of fungi, and either positively or negatively related to the relative abundance of selected microbial phyla, when biocrust\uffe2\uff80\uff90forming mosses were absent. Conversely, we found an overall lack of relationship between aridity and the relative abundance and richness of microbial communities under biocrust\uffe2\uff80\uff90forming mosses.
Our results suggest that biocrust\uffe2\uff80\uff90forming mosses mitigate the impact of aridity on the community composition of globally distributed microbial taxa, and the diversity of fungi. They emphasize the importance of maintaining biocrusts as a sanctuary for soil microbes in drylands.
Our findings indicate the importance of paleoclimatic information to improve quantitative predictions of global soil C stocks.
Microorganisms carrying pmoA and nosZ genes are major drivers of methane and nitrous oxide fluxes from soils. However, most studies on these organisms have been conducted in mesic ecosystems; therefore, little is known about the factors driving their distribution in drylands, the largest biome on Earth. We conducted a global survey to evaluate the role of climate\uffe2\uff80\uff90 and soil\uffe2\uff80\uff90related variables as predictors of the richness, abundance and community structure of bacteria carrying pmoA and nosZ genes.
LocationEighty dryland ecosystems distributed worldwide.
Time periodFrom February 2006 to December 2011.
Major taxa studiedMethanotrophic (carrying the pmoA gene) and denitrifiying (carrying the nosZ gene) bacteria.
MethodsWe used data from a field survey and structural equation modelling to evaluate the direct and indirect effects of climatic (aridity, rainfall seasonality and mean annual temperature) and soil (organic carbon, pH and texture) variables on the total abundance, richness and community structure of microorganisms carrying pmoA and nosZ genes.
ResultsTaxa related to Methylococcus capsulatus or Methylocapsa sp., often associated with mesic environments, were common in global drylands. The abundance and richness of methanotrophs were not associated with climate or soil properties. However, mean annual temperature, rainfall seasonality, organic C, pH and sand content were highly correlated with their community structure. Aridity and soil variables, such as sand content and pH, were correlated with the abundance, community structure and richness of the nosZ bacterial community.
Main conclusionsOur study provides new insights into the drivers of the abundance, richness and community structure of soil microorganisms carrying pmoA and nosZ genes in drylands worldwide. We highlight how ongoing climate change will alter the structure of soil microorganisms, which might affect the net CH4 exchange and will probably reduce the capacity of dryland soils to carry out the final step of denitrification, favouring net N2O emissions.Under controlled laboratory conditions, high and low ammonium availability are known to favor soil ammonia-oxidizing bacteria (AOB) and archaea (AOA) communities, respectively. However, whether this niche segregation is maintained under field conditions in terrestrial ecosystems remains unresolved, particularly at the global scale. We hypothesized that perennial vegetation might favor AOB vs. AOA communities compared with adjacent open areas devoid of perennial vegetation (i.e., bare soil) via several mechanisms, including increasing the amount of ammonium in soil. To test this niche-differentiation hypothesis, we conducted a global field survey including 80 drylands from 6 continents. Data supported our hypothesis, as soils collected under plant canopies had higher levels of ammonium, as well as higher richness (number of terminal restriction fragments; T-RFs) and abundance (qPCR amoA genes) of AOB, and lower richness and abundance of AOA, than those collected in open areas located between plant canopies. Some of the reported associations between plant canopies and AOA and AOB communities can be a consequence of the higher organic matter and available N contents found under plant canopies. Other aspects of soils associated with vegetation including shading and microclimatic conditions might also help explain our results. Our findings provide strong evidence for niche differentiation between AOA and AOB communities in drylands worldwide, advancing our understanding of their ecology and biogeography at the global scale.Under controlled laboratory conditions, high and low ammonium availability are known to favor soil ammonia-oxidizing bacteria (AOB) and archaea (AOA) communities, respectively. However, whether this niche segregation is maintained under field conditions in terrestrial ecosystems remains unresolved, particularly at the global scale. We hypothesized that perennial vegetation might favor AOB vs. AOA communities compared with adjacent open areas devoid of perennial vegetation (i.e., bare soil) via several mechanisms, including increasing the amount of ammonium in soil. To test this niche-differentiation hypothesis, we conducted a global field survey including 80 drylands from 6 continents. Data supported our hypothesis, as soils collected under plant canopies had higher levels of ammonium, as well as higher richness (number of terminal restriction fragments; T-RFs) and abundance (qPCR amoA genes) of AOB, and lower richness and abundance of AOA, than those collected in open areas located between plant canopies. Some of the reported associations between plant canopies and AOA and AOB communities can be a consequence of the higher organic matter and available N contents found under plant canopies. Other aspects of soils associated with vegetation including shading and microclimatic conditions might also help explain our results. Our findings provide strong evidence for niche differentiation between AOA and AOB communities in drylands worldwide, advancing our understanding of their ecology and biogeography at the global scale. Our findings indicate the importance of paleoclimatic information to improve quantitative predictions of global soil C stocks.
The relationship between soil microbial communities and the resistance of multiple ecosystem functions linked to C, N and P cycling (multifunctionality resistance) to global change has never been assessed globally in natural ecosystems. We collected soils from 59 dryland ecosystems worldwide to investigate the importance of microbial communities as predictor of multifunctionality resistance to climate change and nitrogen fertilisation. Multifunctionality had a lower resistance to wetting\uffe2\uff80\uff93drying cycles than to warming or N deposition. Multifunctionality resistance was regulated by changes in microbial composition (relative abundance of phylotypes) but not by richness, total abundance of fungi and bacteria or the fungal: bacterial ratio. Our results suggest that positive effects of particular microbial taxa on multifunctionality resistance could potentially be controlled by altering soil pH. Together, our work demonstrates strong links between microbial community composition and multifunctionality resistance in dryland soils from six continents, and provides insights into the importance of microbial community composition for buffering effects of global change in drylands worldwide.
Recent research indicates that increased aridity linked to climate change will reduce the diversity of soil microbial communities and shift their community composition in drylands, Earth's largest biome. However, we lack both a theoretical framework and solid empirical evidence of how important biotic components from drylands, such as biocrust\uffe2\uff80\uff90forming mosses, will regulate the responses of microbial communities to expected increases in aridity with climate change.
Here we report results from a cross\uffe2\uff80\uff90continental (North America, Europe and Australia) survey of 39 locations from arid to humid ecosystems, where we evaluated how biocrust\uffe2\uff80\uff90forming mosses regulate the relationship between aridity and the community composition and diversity of soil bacteria and fungi in dryland ecosystems.
Increasing aridity was negatively related to the richness of fungi, and either positively or negatively related to the relative abundance of selected microbial phyla, when biocrust\uffe2\uff80\uff90forming mosses were absent. Conversely, we found an overall lack of relationship between aridity and the relative abundance and richness of microbial communities under biocrust\uffe2\uff80\uff90forming mosses.
Our results suggest that biocrust\uffe2\uff80\uff90forming mosses mitigate the impact of aridity on the community composition of globally distributed microbial taxa, and the diversity of fungi. They emphasize the importance of maintaining biocrusts as a sanctuary for soil microbes in drylands.
Microorganisms carrying pmoA and nosZ genes are major drivers of methane and nitrous oxide fluxes from soils. However, most studies on these organisms have been conducted in mesic ecosystems; therefore, little is known about the factors driving their distribution in drylands, the largest biome on Earth. We conducted a global survey to evaluate the role of climate\uffe2\uff80\uff90 and soil\uffe2\uff80\uff90related variables as predictors of the richness, abundance and community structure of bacteria carrying pmoA and nosZ genes.LocationEighty dryland ecosystems distributed worldwide.
Time periodFrom February 2006 to December 2011.
Major taxa studiedMethanotrophic (carrying the pmoA gene) and denitrifiying (carrying the nosZ gene) bacteria.
MethodsWe used data from a field survey and structural equation modelling to evaluate the direct and indirect effects of climatic (aridity, rainfall seasonality and mean annual temperature) and soil (organic carbon, pH and texture) variables on the total abundance, richness and community structure of microorganisms carrying pmoA and nosZ genes.
ResultsTaxa related to Methylococcus capsulatus or Methylocapsa sp., often associated with mesic environments, were common in global drylands. The abundance and richness of methanotrophs were not associated with climate or soil properties. However, mean annual temperature, rainfall seasonality, organic C, pH and sand content were highly correlated with their community structure. Aridity and soil variables, such as sand content and pH, were correlated with the abundance, community structure and richness of the nosZ bacterial community.
Main conclusionsOur study provides new insights into the drivers of the abundance, richness and community structure of soil microorganisms carrying pmoA and nosZ genes in drylands worldwide. We highlight how ongoing climate change will alter the structure of soil microorganisms, which might affect the net CH4 exchange and will probably reduce the capacity of dryland soils to carry out the final step of denitrification, favouring net N2O emissions.Under controlled laboratory conditions, high and low ammonium availability are known to favor soil ammonia-oxidizing bacteria (AOB) and archaea (AOA) communities, respectively. However, whether this niche segregation is maintained under field conditions in terrestrial ecosystems remains unresolved, particularly at the global scale. We hypothesized that perennial vegetation might favor AOB vs. AOA communities compared with adjacent open areas devoid of perennial vegetation (i.e., bare soil) via several mechanisms, including increasing the amount of ammonium in soil. To test this niche-differentiation hypothesis, we conducted a global field survey including 80 drylands from 6 continents. Data supported our hypothesis, as soils collected under plant canopies had higher levels of ammonium, as well as higher richness (number of terminal restriction fragments; T-RFs) and abundance (qPCR amoA genes) of AOB, and lower richness and abundance of AOA, than those collected in open areas located between plant canopies. Some of the reported associations between plant canopies and AOA and AOB communities can be a consequence of the higher organic matter and available N contents found under plant canopies. Other aspects of soils associated with vegetation including shading and microclimatic conditions might also help explain our results. Our findings provide strong evidence for niche differentiation between AOA and AOB communities in drylands worldwide, advancing our understanding of their ecology and biogeography at the global scale.
Recent research indicates that increased aridity linked to climate change will reduce the diversity of soil microbial communities and shift their community composition in drylands, Earth's largest biome. However, we lack both a theoretical framework and solid empirical evidence of how important biotic components from drylands, such as biocrust\uffe2\uff80\uff90forming mosses, will regulate the responses of microbial communities to expected increases in aridity with climate change.
Here we report results from a cross\uffe2\uff80\uff90continental (North America, Europe and Australia) survey of 39 locations from arid to humid ecosystems, where we evaluated how biocrust\uffe2\uff80\uff90forming mosses regulate the relationship between aridity and the community composition and diversity of soil bacteria and fungi in dryland ecosystems.
Increasing aridity was negatively related to the richness of fungi, and either positively or negatively related to the relative abundance of selected microbial phyla, when biocrust\uffe2\uff80\uff90forming mosses were absent. Conversely, we found an overall lack of relationship between aridity and the relative abundance and richness of microbial communities under biocrust\uffe2\uff80\uff90forming mosses.
Our results suggest that biocrust\uffe2\uff80\uff90forming mosses mitigate the impact of aridity on the community composition of globally distributed microbial taxa, and the diversity of fungi. They emphasize the importance of maintaining biocrusts as a sanctuary for soil microbes in drylands.