[Fine root nitrogen contents and morphological adaptations of alpine plants].

Nitrogen and carbon contents of fine roots were studied for 92 alpine plant species in the Northwest Caucasus. Nitrogen content ranged from 0.43% (Bromus variegatus) to 3.75% (Corydalis conorhiza) with mean value 1.3%. Carbon content ranged from 40.3% (Corydalis conorhiza) to 51.7% (Empetrum nigrum) with mean value 43.4%. C:N ratio was found to be 34:1 which is higher than the worldwide mean. Eudicot's roots had higher N concentration (1.37 +/- 0.07) than monocot's ones (0.95 +/- 0.09). Among the life forms, carbon content increased in the following order: geophytes < hemicriptophytes < chamaephytes. Specific root length positively correlated with nitrogen root content and negatively--with carbon root content. Species with larger leaves and higher specific root area had more nitrogen and less carbon in roots in comparison with species with small leaves. There were positive correlations between leaf and root nitrogen, as well as carbon, contents. Regrowth rate; seed size, aboveground biomass, and vegetation mobility were not related with root nitrogen content. Our results corroborate the poor and rich soil adaptation syndromes. Species of competitive and ruderal (sensu Grime) strategies are more typical for alpine meadows and snow bed communities. They had higher nitrogen contents in leaves and roots, larger leaves with higher water content and higher rate of seed production. On the other hand, stress-tolerant plants had higher carbon and less nitrogen concentrations in their roots and leaves, smaller leaves and specific leaf area

Quantitative assessment of the differential impacts of arbuscular and ectomycorrhiza on soil carbon cycling

A significant fraction of carbon stored in the Earth’s soil moves through arbuscular mycorrhiza(AM) and ectomycorrhiza (EM). The impacts of AM and EM on the soil carbon budgetare poorly understood.We propose a method to quantify the mycorrhizal contribution to carbon cycling, explicitlyaccounting for the abundance of plant-associated and extraradical mycorrhizal mycelium. Wediscuss the need to acquire additional data to use our method, and present our new globaldatabase holding information on plant species-by-site intensity of root colonization by mycorrhizas.We demonstrate that the degree of mycorrhizal fungal colonization has globally consistentpatterns across plant species. This suggests that the level of plant species-specific rootcolonization can be used as a plant trait.To exemplify our method, we assessed the differential impacts of AM : EM ratio and EMshrub encroachment on carbon stocks in sub-arctic tundra. AM and EM affect tundra carbonstocks at different magnitudes, and via partly distinct dominant pathways: via extraradicalmycelium (both EM and AM) and via mycorrhizal impacts on above- and belowground biomasscarbon (mostly AM).Our method provides a powerful tool for the quantitative assessment of mycorrhizal impacton local and global carbon cycling processes, paving the way towards an improved understandingof the role of mycorrhizas in the Earth’s carbon cycle.Conservation Biolog

Dataset: BioTIME: A database of biodiversity time series for the Anthropocene

The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. The database consists of 11 tables; one raw data table plus ten related meta data tables. For further information please see our associated data paper. This data consists of several elements: BioTIMESQL_02_04_2018.sql - an SQL file for the full public version of BioTIME which can be imported into any mySQL database. BioTIMEQuery_02_04_2018.csv - data file, although too large to view in Excel, this can be read into several software applications such as R or various database packages. BioTIMEMetadata_02_04_2018.csv - file containing the meta data for all studies. BioTIMECitations_02_04_2018.csv - file containing the citation list for all studies. BioTIMECitations_02_04_2018.xlsx - file containing the citation list for all studies (some special characters are not supported in the csv format). BioTIMEInteractions_02_04_2018.Rmd - an r markdown page providing a brief overview of how to interact with the database and associated .csv files (this will not work until field paths and database connections have been added/updated)

Temperature and pH define the realised niche space of arbuscular mycorrhizal fungi

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Temperature and pH define the realised niche space of arbuscular mycorrhizal fungi

The arbuscular mycorrhizal (AM) fungi are a globally distributed group of soil organisms that play critical roles in ecosystem function. However, the ecological niches of individual AM fungal taxa are poorly understood. We collected > 300 soil samples from natural ecosystems worldwide and modelled the realised niches of AM fungal virtual taxa (VT; approximately species‐level phylogroups). We found that environmental and spatial variables jointly explained VT distribution worldwide, with temperature and pH being the most important abiotic drivers, and spatial effects generally occurring at local to regional scales. While dispersal limitation could explain some variation in VT distribution, VT relative abundance was almost exclusively driven by environmental variables. Several environmental and spatial effects on VT distribution and relative abundance were correlated with phylogeny, indicating that closely related VT exhibit similar niche optima and widths. Major clades within the Glomeraceae exhibited distinct niche optima, Acaulosporaceae generally had niche optima in low pH and low temperature conditions, and Gigasporaceae generally had niche optima in high precipitation conditions. Identification of the realised niche space occupied by individual and phylogenetic groups of soil microbial taxa provides a basis for building detailed hypotheses about how soil communities respond to gradients and manipulation in ecosystems worldwide