Yao J., Zhang C., De Cáceres M., Legendre P., Zhao X. (2019) Variation in compositional and structural components of community assemblage and its determinants. Journal of Vegetation Science. 30: 257-268.LinkDoi: 10.1111/jvs.12708
Questions: What are the ecological processes that determine the spatial distribution of species and species diversity? Partitioning beta diversity can provide fundamental insights into the processes that determine the spatial variation of species assemblages. However, studying beta diversity is conventionally based only on species composition data, ignoring the structural component of communities. Study site: Temperate mixed broadleaf–conifer forest in Jiaohe, Jilin Province, northeastern China. Methods: We characterized the variation of community assemblages in terms of species composition, size structure, or considering both components. We then employed environmental and spatial variables as explanatory factors to partition the variation in both compositional and structural components of community assemblage and assess the relative contributions of the niche and neutral processes to community assembly. Results: The values of overall beta diversity (BD statistics) and the relative contribution of individual sampling units to beta diversity (LCBD indices) depended on whether the species composition, size structure, or both together had been taken into account. The value of compositional–structural beta diversity was the largest, followed by traditional compositional beta diversity; the smallest was the structural beta diversity. The sites with high contributions to beta diversity (LCBD values) varied among structural and compositional components. The explanatory power of the environmental variables and the spatial variables also varied widely with different components of a community. The combination of environmental and spatial variables explained the highest proportion of variation (43.8%) in the compositional component and explained the lowest proportion of variation (25.4%) in the structural component of community assemblage. Conclusion: Both deterministic and stochastic processes are acting to determine community assemblages in terms of species composition and structure in our temperate forest site. Our study highlights the importance of considering the structural component of forest communities, in addition to compositional data, when studying beta diversity. © 2018 International Association for Vegetation Science
Zhang W., Brandt M., Penuelas J., Guichard F., Tong X., Tian F., Fensholt R. (2019) Ecosystem structural changes controlled by altered rainfall climatology in tropical savannas. Nature Communications. 10: 0-0.LinkDoi: 10.1038/s41467-019-08602-6
Tropical savannas comprise mixed woodland grassland ecosystems in which trees and grasses compete for water resources thereby maintaining the spatial structuring of this ecosystem. A global change in rainfall climatology may impact the structure of tropical savanna ecosystems by favouring woody plants, relative to herbaceous vegetation. Here we analysed satellite data and observed a relatively higher increase in woody vegetation (5%) as compared to the increase in annual maximum leaf area index (LAI max , an indicator of the total green vegetation production) (3%) in arid and semi-arid savannas over recent decades. We further observed a declining sensitivity of LAI max to annual rainfall over 56% of the tropical savannas, spatially overlapping with areas of increased woody cover and altered rainfall climatology. This suggests a climate-induced shift in the coexistence of woody and herbaceous vegetation in savanna ecosystems, possibly caused by altered hydrological conditions with significance for land cover and associated biophysical effects such as surface albedo and evapotranspiration. © 2019, The Author(s).
Zhao J.J., Shen X.-J., Domene X., Alcañiz J.-M., Liao X., Palet C. (2019) Comparison of biochars derived from different types of feedstock and their potential for heavy metal removal in multiple-metal solutions. Scientific Reports. 9: 0-0.LinkDoi: 10.1038/s41598-019-46234-4
Three different types of feedstocks and their biochars were used to remove Cr(III), Cd(II), Cu(II) and Pb(II) ions from a mixture of multiple heavy metals. The effect of the initial concentration of heavy metals in solution has been analysed, and kinetics modelling and a comparison of the adsorption capacity of such materials have been performed to elucidate the possible adsorption mechanisms. The results show that the adsorption capacity is dependent on the type of feedstock and on the pyrolysis conditions. The adsorption capacity of the biomass types is ranked as follows: FO (from sewage sludge)>> LO > ZO (both from agriculture biomass waste)>> CO (from wood biomass waste). Biochars, which are the product of the pyrolysis of feedstocks, clearly improve the adsorption efficiency in the case of those derived from wood and agricultural biomasses. Complexation and cation exchange have been found to be the two main adsorption mechanisms in systems containing multiple heavy metals, with cation exchange being the most significant. The pore structure of biomass/biochar cannot be neglected when investigating the adsorption mechanism of each material. All the disposal biomasses presented here are good alternatives for heavy metal removal from wastewaters. © 2019, The Author(s).
Zheng B.-X., Ding K., Yang X.-R., Wadaan M.A.M., Hozzein W.N., Peñuelas J., Zhu Y.-G. (2019) Straw biochar increases the abundance of inorganic phosphate solubilizing bacterial community for better rape (Brassica napus) growth and phosphate uptake. Science of the Total Environment. 647: 1113-1120.LinkDoi: 10.1016/j.scitotenv.2018.07.454
The direct application of inorganic-phosphate-solubilizing bacteria (iPSBs) for improving the efficiency of phosphorus (P) use leads to a low rate of bacterial survival. Biochar is a good inoculum carrier for microbial survival, and diverse feedstocks can have different effects. We generated an iPSB community using seven selected iPSB strains with various phylogenic taxonomies and P-solubilizing abilities. Biochar was then inoculated with the iPSB community and applied to soil in pots seeded with rape (Brassica napus). Growth of the rape for four weeks and the effects of biochars produced from six raw feedstocks, rice straw, rice husks, soybean straw, peanut shells, corn cobs and wood, were compared. The synthetic iPSB community had a larger capacity to solubilize inorganic P and exude organic anions than any of the individual strains. The structure of the iPSB community was analyzed by high-throughput sequencing four weeks after inoculation. All seven iPSB strains were detected, dominated by Arthrobacter defluvii 06-OD12. The abundance of the iPSB community was significantly correlated with rape biomass, P content and P uptake (P
Zheng B.-X., Zhang D.-P., Wang Y., Hao X.-L., Wadaan M.A.M., Hozzein W.N., Peñuelas J., Zhu Y.-G., Yang X.-R. (2019) Responses to soil pH gradients of inorganic phosphate solubilizing bacteria community. Scientific Reports. 9: 0-0.LinkDoi: 10.1038/s41598-018-37003-w
Soil pH is commonly considered a dominant factor affecting the function of microbiota. Few studies, however, have focused on communities of bacteria able to solubilize inorganic phosphate (iPSB), which are important for the mobilization of soil phosphorus (P), because finding an effective method to assess the abundance and diversity of iPSB communities is difficult. We used a newly reported method of database alignment and quantified the gene pqqC to analyze the compositions of iPSB communities from five soils with pH gradients ranging from 4 to 8. The iPSB community structure differed significantly between these soil types. Among iPSB community, Bacillus was the dominant genus, followed by Arthrobacter and Streptomyces. A redundancy analysis indicated that soil pH was the most important of 15 soil factors and their pairwise interactions, accounting for 5.12% of the variance. The abundance of the iPSB communities increased with pH within the gradients which was confirmed by experimental adjustment of pH, suggesting that the defect P status in high pH soil was speculated as the driving force of iPSB community population. Our study demonstrated the dominant role of soil pH on the iPSB community, which may contribute to the understanding the possible mechanism of microbial P mobilization for better improvement of P use-efficiency. © 2019, The Author(s).
(2018) Continental mapping of forest ecosystem functions reveals a high but unrealised potential for forest multifunctionality. . : -.LinkDoi: https://doi.org/10.1111/ele.12868
(2018) Annual Report CREAF 2017. . : -.
(2018) Fitxa AIGUA I CANVI GLOBAL (català). . : -.
(2018) Yearly fluctuations of flower landscape in a Mediterranean scrubland: Consequences for floral resource availability. . : -.LinkDoi: https://doi.org/10.1371/journal.pone.0191268
(2018) Early stage litter decomposition across biomes. . : -.LinkDoi: 10.1016/j.scitotenv.2018.01.012
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