High N, dry: Experimental nitrogen deposition exacerbates native shrub loss and nonnative plant invasion during extreme drought.

Hotter, longer, and more frequent global change-type drought events may profoundly impact terrestrial ecosystems by triggering widespread vegetation mortality. However, severe drought is only one component of global change, and ecological effects of drought may be compounded by other drivers, such as anthropogenic nitrogen (N) deposition and nonnative plant invasion. Elevated N deposition, for example, may reduce drought tolerance through increased plant productivity, thereby contributing to drought-induced mortality. High N availability also often favors invasive, nonnative plant species, and the loss of woody vegetation due to drought may create a window of opportunity for these invaders. We investigated the effects of multiple levels of simulated N deposition on a Mediterranean-type shrubland plant community in southern California from 2011 to 2016, a period coinciding with an extreme, multiyear drought in the region. We hypothesized that N addition would increase native shrub productivity, but that this would increase susceptibility to drought and result in increased shrub loss over time. We also predicted that N addition would favor nonnatives, especially annual grasses, leading to higher biomass and cover of these species. Consistent with these hypotheses, we found that high N availability increased native shrub canopy loss and mortality, likely due to the higher productivity and leaf area and reduced water-use efficiency we observed in shrubs subject to N addition. As native shrub cover declined, we also observed a concomitant increase in cover and biomass of nonnative annuals, particularly under high levels of experimental N deposition. Together, these results suggest that the impacts of extended drought on shrubland ecosystems may be more severe under elevated N deposition, potentially contributing to the widespread loss of native woody species and vegetation-type conversion

Genome size unaffected by moderate changes in climate and phosphorus availability in Mediterranean plants

Nuclear DNA amount has been assessed in a set of 6 Mediterranean plant species including subshrubs, shrubs and trees (Dorycnium pentaphyllum Scop., Erica multiflora L., Fumana ericoides (L.) Webb, Globularia alypum L., Pinus halepensis Mill and Rosmarinus officinalis L.). Genome size values have been assessed by flow cytometry from plants growing in their natural habitats, in plots with a particular experimental design to measure the effects of drought and warming and also with different phosphorus (P) concentration in soil. 2C values have been fairly constant in all the species studied under all conditions. These results, which provide first records of DNA content in all the studied species except for P. halepensis, suggest that moderate changes in climate such as a 0.73°C warming or a drought consisting of 19% decrease in soil moisture on an average of 7 years and the consequent changes in the soil availability of such an essential element as P (ranging from 80 to 160 g/g) do not affect genome size stability, at least not by producing rapid and significant variations.Key words: C-value, drought, Mediterranean plants, nuclear DNA amount, phosphorus, warming

El rol dels terpens en la competència entre plantes invasores i natives a Hawaii

Els terpens, hidrocarburs derivats de l'isoprè, són emesos i emmagatzemats per moltes plantes. La seva funció biològica i ecològica és estudiada des de fa uns anys, havent estat proposades diverses possibles funcions, com per exemple la protecció davant dels herbívors o com a mecanisme antiestrès metabòlic. Investigacions realitzades per científics del CREAF a les illes Hawaii han permès detectar diferències en l'acumulació foliar de terpens entre les espècies nadiues i invasives a través de l'screening efectuat en una àmplia mostra de les principals espècies forestals natives i invasives a l'illa d'Oahu. Aquests resultats aporten noves pistes per conèixer els mecanismes que expliquen l'èxit competitiu que permet que moltes espècies introduïdes en un nou hàbitat esdevinguin un problema ecològic per la seva expansió i exclusió competitiva d'espècies nadiues.Los terpenos, hidrocarburos derivados del isopreno, son emitidos y almacenados por muchas plantas. Su función biológica y ecológica está siendo estudiada desde hace unos años, habiendo sido propuestas varias posibles funciones, como por ejemplo la protección frente a los herbívoros o como mecanismo antiestrés metabólico. Investigaciones realizadas por científicos del CREAF en las islas Hawai han permitido detectar diferencias en la acumulación foliar de terpenos entre las especies nativas e invasivas a través del screening efectuado en una amplia muestra de las principales especies forestales nativas y invasivas en la Isla de Oahu. Estos resultados aportan nuevas pistas para conocer los mecanismos que explican el éxito competitivo que permite que muchas especies introducidas en un nuevo hábitat se conviertan en un problema ecológico por su expansión y exclusión competitiva de especies nativas

A unifying conceptual model for the environmental responses of isoprene emissions from plants

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND AND AIMS: Isoprene is the most important volatile organic compound emitted by land plants in terms of abundance and environmental effects. Controls on isoprene emission rates include light, temperature, water supply and CO2 concentration. A need to quantify these controls has long been recognized. There are already models that give realistic results, but they are complex, highly empirical and require separate responses to different drivers. This study sets out to find a simpler, unifying principle. METHODS: A simple model is presented based on the idea of balancing demands for reducing power (derived from photosynthetic electron transport) in primary metabolism versus the secondary pathway that leads to the synthesis of isoprene. This model's ability to account for key features in a variety of experimental data sets is assessed. KEY RESULTS: The model simultaneously predicts the fundamental responses observed in short-term experiments, namely: (1) the decoupling between carbon assimilation and isoprene emission; (2) a continued increase in isoprene emission with photosynthetically active radiation (PAR) at high PAR, after carbon assimilation has saturated; (3) a maximum of isoprene emission at low internal CO2 concentration (ci) and an asymptotic decline thereafter with increasing ci; (4) maintenance of high isoprene emissions when carbon assimilation is restricted by drought; and (5) a temperature optimum higher than that of photosynthesis, but lower than that of isoprene synthase activity. CONCLUSIONS: A simple model was used to test the hypothesis that reducing power available to the synthesis pathway for isoprene varies according to the extent to which the needs of carbon assimilation are satisfied. Despite its simplicity the model explains much in terms of the observed response of isoprene to external drivers as well as the observed decoupling between carbon assimilation and isoprene emission. The concept has the potential to improve global-scale modelling of vegetation isoprene emission.We thank Karena McKinney for providing the original isoprene data for the Harvard forest site. We thank Russell Monson and Ru¨diger Grote for their helpful and constructive comments on the manuscript. C.M. and I.C.P. have received funding from the European Community’s Seventh Framework Programme (FP7 2007 – 2013) under grant agreement no. 238366

Vapor-pressure deficit and extreme climatic variables limit tree growth

Assessing the effect of global warming on forest growth requires a better understanding of species-specific responses to climate change conditions. Norway spruce and European beech are among the dominant tree species in Europe and are largely used by the timber industry. Their sensitivity to changes in climate and extreme climatic events, however, endangers their future sustainability. Identifying the key climatic factors limiting their growth and survival is therefore crucial for assessing the responses of these two species to ongoing climate change. We studied the vulnerability of beech and spruce to warmer and drier conditions by transplanting saplings from the top to the bottom of an elevational gradient in the Jura Mountains in Switzerland. We (1) demonstrated that a longer growing season due to warming could not fully account for the positive growth responses, and the positive effect on sapling productivity was species-dependent, (2) demonstrated that the contrasting growth responses of beech and spruce were mainly due to different sensitivities to elevated vapor-pressure deficits (VPD), (3) determined the species-specific limits to VPD above which growth rate began to decline, and (4) demonstrated that models incorporating extreme climatic events could account for the response of growth to warming better than models using only average values. These results support that the sustainability of forest trees in the coming decades will depend on how extreme climatic events will change, irrespective of the overall warming trend

Impact of the COVID-19 pandemic on the care of cancer patients in Spain

Coronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Càncer; EspanyaCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Cáncer; EspañaCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Cancer; SpainBackground Studies evaluating the effects of the COVID-19 pandemic on public healthcare systems are limited, particularly in cancer management. As no such studies have been carried out in Spain, our objective is to describe and quantify the impact of the COVID-19 pandemic on cancer patients in Spanish hospitals during the first wave of the pandemic. Materials and methods This retrospective, multicenter, nationwide study collected information from hospital departments treating oncology patients. An electronic questionnaire comparing outcomes and management of oncohematological patients for the March-June 2019 and March-June 2020 periods was used. Results Information from 78 departments (36 tertiary hospitals) was analyzed. Forty-four departments implemented adapted protocols during March 2020. Most of these (n = 38/44; 86.4%) carried out COVID-19 triage, while 26 of 44 (59.1%) carried out onsite polymerase chain reaction tests for clinically suspected cases. A shift from in-person to telephone visits was observed in 43 of 44 (97.7%) departments. Comparing the March-June 2019 and March-June 2020 periods, the number of new patients decreased by 20.8% (from 160.2 to 126.4). Decreases were also seen in the mean number of total (2858.2 versus 1686.1) and cancer (465.5 versus 367.2) biopsies, as well as the mean number of bone marrow biopsies (30.5 versus 18.6). Concerning the number of patients visiting specific cancer care departments, a decrease from 2019 to 2020 was seen for mean number of chemotherapy treatments (712.7 versus 643.8) and radiation therapy (2169.9 versus 2139.9). Finally, a reduction from 2019 to 2020 of 12.9% (from 8.6 to 7.4) in the mean number of patients included in clinical trials was noted. Conclusions This study provides the first comprehensive data concerning the impact of COVID-19 on cancer care in Spain. The pandemic caused a 20.8% decrease in newly diagnosed patients, which may impact future outcomes. Measures must be taken to ensure cancer management receives priority in times of healthcare emergencies.This work was supported by funding from the AECC, a non-profit organization, whose medical department funded the study and the medical writing (no grant number)

Caracterización de la fenología de la vegetación a escala global mediante series temporales SPOT VEGETATION

Revista oficial de la Asociación Española de Teledetección[EN] Land surface phenology from time series of satellite data are expected to contribute to improve the represen-tation of vegetation phenology in earth system models. We characterized the baseline phenology of the vegetation at the global scale from GEOCLIM-LAI, a global climatology of leaf area index (LAI) derived from 1-km SPOT VEGETATION time series for 1999-2010. The calibration with ground measurements showed that the start and end of season were best identified using respectively 30% and 40% threshold of LAI amplitude values. The satellite-derived phenology was spatially consistent with the global distributions of climatic drivers and biome land cover. The accuracy of the derived phenological metrics, evaluated using available ground observations for birch forests in Europe, cherry in Asia and lilac shrubs in North America showed an overall root mean square error lower than 19 days for the start, end and length of season, and good agreement between the latitudinal gradients of VEGETATION LAI phenology and ground data[ES] La teledetección debe contribuir a mejorar la representación de la fenología en los modelos climáticos. En este estudio se ha caracterizado la fenología típica de la vegetación a escala global mediante GEOCLIM-LAI, una climatología del índice de área foliar (LAI) calculada a partir de series temporales en el periodo 1999-2010 de datos SPOT VEGETATION a 1-km de resolución espacial. A partir de la calibración con observaciones in situ, el inicio y fin de la estación de crecimiento se han definido como la fecha para la cual el LAI alcanza, respectivamente, el 30% y 40% de la amplitud de su ciclo anual. Los patrones espaciales de la fenología de satélite muestran una gran consistencia con la distribución espacial de cubiertas vegetales y factores climáticos. La comparación con medidas in situ para las fe-nofases correspondientes al inicio, fin y duración de la estación de crecimiento de abedul común en Europa, cerezo en Asia y lilo en Norte América muestra errores medios menores de 19 días, y un gran acuerdo en el gradiente latitudinal de la fenología observada in situ y estimada a partir de series temporales LAI VEGETATION.Este trabajo ha sido financiado en parte por el programa Europeo de observación Copernicus Global Land, y los proyectos FP7 geoland2 (218795), GIOBIO (32-566), LONGLOVE (32-594), CGL2013-48074-P, SGR 2014-274 y IMBALANCE-P (ERC-2013-SyG-610028). A. Verger fue beneficiario de un contrato Juan de la Cierva del Ministerio de Ciencia e Innovación, Gobierno de España.Verger, A.; Filella, I.; Baret, F.; Peñuelas, J. (2016). Land surface phenology from SPOT VEGETATION time series. Revista de Teledetección. (47):1-11. https://doi.org/10.4995/raet.2016.5718SWORD1114

Atmospheric science: the self-cleansing ability of prehistoric air

Isotopic data from an ice core have been used to estimate atmospheric oxidant levels during past climate transitions — pointing to relatively unexplored climate feedbacks as drivers of atmospheric composition