Courtois E.A., Stahl C., Van den Berge J., Bréchet L., Van Langenhove L., Richter A., Urbina I., Soong J.L., Peñuelas J., Janssens I.A. (2018) Correction to: Spatial Variation of Soil CO2, CH4 and N2O Fluxes Across Topographical Positions in Tropical Forests of the Guiana Shield (Ecosystems, (2018), (1-14), 10.1007/s10021-018-0232-6). Ecosystems. : 0-0.EnllaçDoi: 10.1007/s10021-018-0281-x
This paper was published with several formatting errors. It will be republished with corrections in place. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
Courtois E.A., Stahl C., van Den Berge J., Bréchet L., van Langenhove L., Richter A., Urbina I., Soong J.L., Peñuelas J., Janssens I.A. (2018) Spatial Variation of Soil CO2, CH4 and N2O Fluxes Across Topographical Positions in Tropical Forests of the Guiana Shield. Ecosystems. : 1-14.EnllaçDoi: 10.1007/s10021-018-0232-6
The spatial variation of soil greenhouse gas fluxes (GHG; carbon dioxide—CO2, methane—CH4 and nitrous oxide—N2O) remains poorly understood in highly complex ecosystems such as tropical forests. We used 240 individual flux measurements of these three GHGs from different soil types, at three topographical positions and in two extreme hydric conditions in the tropical forests of the Guiana Shield (French Guiana, South America) to (1) test the effect of topographical positions on GHG fluxes and (2) identify the soil characteristics driving flux variation in these nutrient-poor tropical soils. Surprisingly, none of the three GHG flux rates differed with topographical position. CO2 effluxes covaried with soil pH, soil water content (SWC), available nitrogen and total phosphorus. The CH4 fluxes were best explained by variation in SWC, with soils acting as a sink under drier conditions and as a source under wetter conditions. Unexpectedly, our study areas were generally sinks for N2O and N2O fluxes were partly explained by total phosphorus and available nitrogen concentrations. This first study describing the spatial variation of soil fluxes of the three main GHGs measured simultaneously in forests of the Guiana Shield lays the foundation for specific studies of the processes underlying the observed patterns. © 2018 Springer Science+Business Media, LLC, part of Springer Nature
Urbina I., Sardans J., Beierkuhnlein C., Jentsch A., Backhaus S., Grant K., Kreyling J., Penuelas J. (2015) Shifts in the elemental composition of plants during a very severe drought. Environmental and Experimental Botany. 111: 63-73.EnllaçDoi: 10.1016/j.envexpbot.2014.10.005
Diverse plant functions (e.g., growth, storage, defense and anti-stress mechanisms) use elements disproportionally. We hypothesized that plants growing under different abiotic and biotic conditions would shift their elemental compositions in response to a very severe drought. We tested this hypothesis by investigating the changes in foliar stoichiometry and species composition from a very severe drought. We also tested the effects of previous droughts (acclimation) on this response. Different species growing in the same community responded more similarly to a very severe drought than did individual species growing in different communities. The stoichiometric shifts were thus more community-dependent than species-dependent. The results also suggested that plants grown in monoculture were less stoichiometrically plastic during the drought than plants grown in a more diverse community. Previous exposure to long-term drought treatments in the same communities did not significantly affect the stoichiometric shifts during the new drought. Differential use of resources may have been responsible for these responses. Monocultured plants, which used the same resources in similar proportions, had more difficulty avoiding direct competition when the resources became scarcer. Moreover, each species tested had a particular elemental composition in all communities and climatic treatments. The differences in foliar elemental compositions were largest between plant functional groups (shrubs and grasses) and smallest among species within the same functional group. Global principal components analyses (PCAs) identified a general tendency for all species, independently of the community in which they grew, toward lower concentrations of K, N, P, Mg and S, and to higher concentrations of C and Fe as the drought advanced. This study has demonstrated the utility of analyses of differences and shifts in plant elemental composition for understanding the processes underlying the responses of plants to changes in biotic and abiotic environmental conditions. © 2014.
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