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
Cramer W., Guiot J., Fader M., Garrabou J., Gattuso J.-P., Iglesias A., Lange M.A., Lionello P., Llasat M.C., Paz S., Peñuelas J., Snoussi M., Toreti A., Tsimplis M.N., Xoplaki E. (2018) Climate change and interconnected risks to sustainable development in the Mediterranean. Nature Climate Change. 8: 972-980.EnllaçDoi: 10.1038/s41558-018-0299-2
Recent accelerated climate change has exacerbated existing environmental problems in the Mediterranean Basin that are caused by the combination of changes in land use, increasing pollution and declining biodiversity. For five broad and interconnected impact domains (water, ecosystems, food, health and security), current change and future scenarios consistently point to significant and increasing risks during the coming decades. Policies for the sustainable development of Mediterranean countries need to mitigate these risks and consider adaptation options, but currently lack adequate information — particularly for the most vulnerable southern Mediterranean societies, where fewer systematic observations schemes and impact models are based. A dedicated effort to synthesize existing scientific knowledge across disciplines is underway and aims to provide a better understanding of the combined risks posed. © 2018, Springer Nature Limited.
Dornelas M., Antão L.H., Moyes F., Bates A.E., Magurran A.E., Adam D., Akhmetzhanova A.A., Appeltans W., Arcos J.M., Arnold H., Ayyappan N., Badihi G., Baird A.H., Barbosa M., Barreto T.E., Bässler C., Bellgrove A., Belmaker J., Benedetti-Cecchi L., Bett B.J., Bjorkman A.D., Błażewicz M., Blowes S.A., Bloch C.P., Bonebrake T.C., Boyd S., Bradford M., Brooks A.J., Brown J.H., Bruelheide H., Budy P., Carvalho F., Castañeda-Moya E., Chen C.A., Chamblee J.F., Chase T.J., Siegwart Collier L., Collinge S.K., Condit R., Cooper E.J., Cornelissen J.H.C., Cotano U., Kyle Crow S., Damasceno G., Davies C.H., Davis R.A., Day F.P., Degraer S., Doherty T.S., Dunn T.E., Durigan G., Duffy J.E., Edelist D., Edgar G.J., Elahi R., Elmendorf S.C., Enemar A., Ernest S.K.M., Escribano R., Estiarte M., Evans B.S., Fan T.-Y., Turini Farah F., Loureiro Fernandes L., Farneda F.Z., Fidelis A., Fitt R., Fosaa A.M., Daher Correa Franco G.A., Frank G.E., Fraser W.R., García H., Cazzolla Gatti R., Givan O., Gorgone-Barbosa E., Gould W.A., Gries C., Grossman G.D., Gutierréz J.R., Hale S., Harmon M.E., Harte J., Haskins G., Henshaw D.L., Hermanutz L., Hidalgo P., Higuchi P., Hoey A., Van Hoey G., Hofgaard A., Holeck K., Hollister R.D., Holmes R., Hoogenboom M., Hsieh C.-H., Hubbell S.P., Huettmann F., Huffard C.L., Hurlbert A.H., Macedo Ivanauskas N., Janík D., Jandt U., Jażdżewska A., Johannessen T., Johnstone J., Jones J., Jones F.A.M., Kang J., Kartawijaya T., Keeley E.C., Kelt D.A., Kinnear R., Klanderud K., Knutsen H., Koenig C.C., Kortz A.R., Král K., Kuhnz L.A., Kuo C.-Y., Kushner D.J., Laguionie-Marchais C., Lancaster L.T., Min Lee C., Lefcheck J.S., Lévesque E., Lightfoot D., Lloret F., Lloyd J.D., López-Baucells A., Louzao M., Madin J.S., Magnússon B., Malamud S., Matthews I., McFarland K.P., McGill B., McKnight D., McLarney W.O., Meador J., Meserve P.L., Metcalfe D.J., Meyer C.F.J., Michelsen A., Milchakova N., Moens T., Moland E., Moore J., Mathias Moreira C., Müller J., Murphy G., Myers-Smith I.H., Myster R.W., Naumov A., Neat F., Nelson J.A., Paul Nelson M., Newton S.F., Norden N., Oliver J.C., Olsen E.M., Onipchenko V.G., Pabis K., Pabst R.J., Paquette A., Pardede S., Paterson D.M., Pélissier R., Peñuelas J., Pérez-Matus A., Pizarro O., Pomati F., Post E., Prins H.H.T., Priscu J.C., Provoost P., Prudic K.L., Pulliainen E., Ramesh B.R., Mendivil Ramos O., Rassweiler A., Rebelo J.E., Reed D.C., Reich P.B., Remillard S.M., Richardson A.J., Richardson J.P., van Rijn I., Rocha R., Rivera-Monroy V.H., Rixen C., Robinson K.P., Ribeiro Rodrigues R., de Cerqueira Rossa-Feres D., Rudstam L., Ruhl H., Ruz C.S., Sampaio E.M., Rybicki N., Rypel A., Sal S., Salgado B., Santos F.A.M., Savassi-Coutinho A.P., Scanga S., Schmidt J., Schooley R., Setiawan F., Shao K.-T., Shaver G.R., Sherman S., Sherry T.W., Siciński J., Sievers C., da Silva A.C., Rodrigues da Silva F., Silveira F.L., Slingsby J., Smart T., Snell S.J., Soudzilovskaia N.A., Souza G.B.G., Maluf Souza F., Castro Souza V., Stallings C.D., Stanforth R., Stanley E.H., Mauro Sterza J., Stevens M., Stuart-Smith R., Rondon Suarez Y., Supp S., Yoshio Tamashiro J., Tarigan S., Thiede G.P., Thorn S., Tolvanen A., Teresa Zugliani Toniato M., Totland Ø., Twilley R.R., Vaitkus G., Valdivia N., Vallejo M.I., Valone T.J., Van Colen C., Vanaverbeke J., Venturoli F., Verheye H.M., Vianna M., Vieira R.P., Vrška T., Quang Vu C., Van Vu L., Waide R.B., Waldock C., Watts D., Webb S., Wesołowski T., White E.P., Widdicombe C.E., Wilgers D., Williams R., Williams S.B., Williamson M., Willig M.R., Willis T.J., Wipf S., Woods K.D., Woehler E.J., Zawada K., Zettler M.L. (2018) BioTIME: A database of biodiversity time series for the Anthropocene. Global Ecology and Biogeography. 27: 760-786.EnllaçDoi: 10.1111/geb.12729
Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. Main types of variables included: The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. Spatial location and grain: BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). Time period and grain: BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. Major taxa and level of measurement: BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates. Software format:.csv and.SQL. © 2018 The Authors. Global Ecology and Biogeography Published by John Wiley & Sons Ltd
Fernández-Martínez M., Llusià J., Filella I., Niinemets Ü., Arneth A., Wright I.J., Loreto F., Peñuelas J. (2018) Nutrient-rich plants emit a less intense blend of volatile isoprenoids. New Phytologist. 220: 773-784.EnllaçDoi: 10.1111/nph.14889
The emission of isoprenoids (e.g. isoprene and monoterpenes) by plants plays an important defensive role against biotic and abiotic stresses. Little is known, however, about the functional traits linked to species-specific variability in the types and rates of isoprenoids emitted and about possible co-evolution of functional traits with isoprenoid emission type (isoprene emitter, monoterpene emitter or both). We combined data for isoprene and monoterpene emission rates per unit dry mass with key functional traits (foliar nitrogen (N) and phosphorus (P) concentrations, and leaf mass per area) and climate for 113 plant species, covering the boreal, wet temperate, Mediterranean and tropical biomes. Foliar N was positively correlated with isoprene emission, and foliar P was negatively correlated with both isoprene and monoterpene emission rate. Nonemitting plants generally had the highest nutrient concentrations, and those storing monoterpenes had the lowest concentrations. Our phylogenetic analyses found that the type of isoprenoid emission followed an adaptive, rather than a random model of evolution. Evolution of isoprenoids may be linked to nutrient availability. Foliar N and P are good predictors of the type of isoprenoid emission and the rate at which monoterpenes, and to a lesser extent isoprene, are emitted. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust
Fernández-Martínez M., Vicca S., Janssens I.A., Carnicer J., Martín-Vide J., Peñuelas J. (2018) The consecutive disparity index, D: a measure of temporal variability in ecological studies. Ecosphere. 9: 0-0.EnllaçDoi: 10.1002/ecs2.2527
Temporal variability in ecological processes has attracted the attention of many disciplines in ecology, which has resulted in the development of several quantitative indices. The coefficient of variation (CV = standard deviation × mean−1) is still one of the most commonly used indices to assess temporal variability, despite being known to present several problems on its assessment (e.g., mean dependence or high sensitivity to rare events). The proportional variability (PV) index was developed to solve some of the CV's drawbacks, but, so far, no variability index takes into account the chronological order of the values in time series. In this paper, we introduce the consecutive disparity index (D), a temporal variability index that takes into account the chronological order of the values, assessing the average rate of change between consecutive values. We used computer simulations and empirical data for fruit production in trees, bird counts, and rodent captures to compare the behavior of D, PV, and CV under different scenarios. D was sensitive to changes in temporal autocorrelation in the negative autocorrelation range, and CV and PV were sensitive in the positive autocorrelation range despite not considering the chronological order of the values. The CV, however, was highly dependent on the mean of the time series, while D and PV were not. Our results demonstrate that, like PV, D solves many of the problems of the CV index while taking into account the chronological order of values in time series. The mathematical and statistical features of D make it a suitable index for analyzing temporal variability in a wide range of ecological studies. © 2018 The Authors.
Filella I., Zhang C., Seco R., Potosnak M., Guenther A., Karl T., Gamon J., Pallardy S., Gu L., Kim S., Balzarolo M., Fernandez-Martinez M., Penuelas J. (2018) A MODIS photochemical reflectance index (PRI) as an estimator of isoprene emissions in a temperate deciduous forest. Remote Sensing. 10: 0-0.EnllaçDoi: 10.3390/rs10040557
The quantification of isoprene and monoterpene emissions at the ecosystem level with available models and field measurements is not entirely satisfactory. Remote-sensing techniques can extend the spatial and temporal assessment of isoprenoid fluxes. Detecting the exchange of biogenic volatile organic compounds (BVOCs) using these techniques is, however, a very challenging goal. Recent evidence suggests that a simple remotely sensed index, the photochemical reflectance index (PRI), which is indicative of light-use efficiency, relative pigment levels and excess reducing power, is a good indirect estimator of foliar isoprenoid emissions. We tested the ability of PRI to assess isoprenoid fluxes in a temperate deciduous forest in central USA throughout the entire growing season and under moderate and extreme drought conditions. We compared PRI time series calculated with MODIS bands to isoprene emissions measured with eddy covariance. MODIS PRI was correlated with isoprene emissions for most of the season, until emissions peaked. MODIS PRI was also able to detect the timing of the annual peak of emissions, even when it was advanced in response to drought conditions. PRI is thus a promising index to estimate isoprene emissions when it is complemented by information on potential emission. It may also be used to further improve models of isoprene emission under drought and other stress conditions. Direct estimation of isoprene emission by PRI is, however, limited, because PRI estimates LUE, and the relationship between LUE and isoprene emissions can be modified by severe stress conditions. © 2018 by the authors.
Gargallo-Garriga A., Preece C., Sardans J., Oravec M., Urban O., Peñuelas J. (2018) Root exudate metabolomes change under drought and show limited capacity for recovery. Scientific Reports. 8: 0-0.EnllaçDoi: 10.1038/s41598-018-30150-0
Root exudates comprise a large variety of compounds released by plants into the rhizosphere, including low-molecular-weight primary metabolites (particularly saccharides, amino acids and organic acids) and secondary metabolites (phenolics, flavonoids and terpenoids). Changes in exudate composition could have impacts on the plant itself, on other plants, on soil properties (e.g. amount of soil organic matter), and on soil organisms. The effects of drought on the composition of root exudates, however, have been rarely studied. We used an ecometabolomics approach to identify the compounds in the exudates of Quercus ilex (holm oak) under an experimental drought gradient and subsequent recovery. Increasing drought stress strongly affected the composition of the exudate metabolome. Plant exudates under drought consisted mainly of secondary metabolites (71% of total metabolites) associated with plant responses to drought stress, whereas the metabolite composition under recovery shifted towards a dominance of primary metabolites (81% of total metabolites). These results strongly suggested that roots exude the most abundant root metabolites. The exudates were changed irreversibly by the lack of water under extreme drought conditions, and the plants could not recover. © 2018, The Author(s).
Hinojo-Hinojo C., Castellanos A.E., Llano-Sotelo J., Peñuelas J., Vargas R., Romo-Leon J.R. (2018) High Vcmax, Jmax and photosynthetic rates of Sonoran Desert species: Using nitrogen and specific leaf area traits as predictors in biochemical models. Journal of Arid Environments. : 0-0.EnllaçDoi: 10.1016/j.jaridenv.2018.04.006
Dryland ecosystems largely control the inter-annual variability of the global carbon cycle. Unfortunately, there is a paucity of data on key biochemical parameters, such as maximum carboxylation velocity (Vcmax25) and electron transport rate (Jmax25), from species in these ecosystems which limits our capacity to model photosynthesis across ecological scales. We studied six dominant C3 shrub and tree species from the Sonoran Desert with different leaf traits and phenological strategies. We characterized Vcmax25 and Jmax25 for each species and assessed which traits or trait combinations were the best predictors of these parameters for biochemical models of photosynthesis. All species had high values of Vcmax25 and Jmax25, mostly explained by high leaf nitrogen content (Narea) and high nitrogen allocation to photosynthetic enzymes comparable to those reported for herbs and crop species but higher than those of shrubs and other functional types in world databases. We found that the high values of Vcmax25 and Jmax25, by increasing rates of photosynthetic reactions, enhance photosynthetic water and nitrogen-use efficiencies and may favor carbon gain under typical conditions in drylands. Our findings improve the parameterization of photosynthesis models, and provide novel implications to common findings of high Narea in dryland species. © 2018 Elsevier Ltd
Hu M., Peñuelas J., Sardans J., Sun Z., Wilson B.J., Huang J., Zhu Q., Tong C. (2018) Stoichiometry patterns of plant organ N and P in coastal herbaceous wetlands along the East China Sea: implications for biogeochemical niche. Plant and Soil. : 0-0.EnllaçDoi: 10.1007/s11104-018-3759-6
Background and aims: Nitrogen (N) and phosphorus (P) are essential nutrients for plant growth, and their availability and stoichiometry play pivotal roles in trophic dynamics and community composition. The biogeochemical niche (BN) hypothesis claims that each species should have an optimal elemental composition and stoichiometry as a consequence of its optimal function in its specific ecological niche. Little attention, however, has been given to N and P stoichiometric patterns and test the BN hypothesis in coastal wetland communities from the perspective of organ and species-specific comparisons. Methods: We investigated factors responsible for changes in N and P stoichiometry patterns in different functional groups in coastal wetlands and tested the BN hypothesis by evaluating N and P composition in whole aboveground plants and organs. Results: Both plant N and P concentrations were high in coastal wetlands, indicating that N and P were not likely limiting, although the N:P ratio was slightly lower than the ratio reported in global and Chinese terrestrial flora. N and P concentrations and N:P ratios varied strongly between C3 and C4 species, among species, and among organs within species. N and P concentrations were not correlated with latitude, mean annual temperature and precipitation, although N:P ratio was weakly correlated with these factors. The differences in N and P concentrations and N:P ratios along the wetland gradients were mainly because of the species-specific community composition of each site. Conclusions: The results are consistent with the BN hypothesis. First, N and P composition is species-specific (homeostatic component of BN), each species tends to maintain its own composition even growing in different sites with different species composition. Second, different species, despite maintaining their own composition, have distinct degree of composition phenotypic flexibility (flexibility component of BN); this different size of “biogeochemical space” was observed when comparing different species living in the same community and the shifts in species BN space and size was observed when comparing populations of the same species living in different sites. © 2018, Springer Nature Switzerland AG.
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