domingo, 4 de septiembre de 2016

Actividades de investigación por créditos para alumnos de la URJC, curso 2016/2017

Si eres estudiante de algún grado en la URJC y te interesa introducirte en el mundo de la investigación en ecología y cambio global, participar en el desarrollo de los proyectos que estamos realizando en el Laboratorio de Ecología de Ecosistemas Semiáridos y Cambio Global y conseguir créditos por esta actividad ahora puedes hacerlo! Tenemos varias vacantes para alumnos que estén interesados en colaborar con nosotros.

Los alumnos interesados colaborarán en las tareas de mantenimiento de los distintos experimentos sobre las consecuencias ecológicas del cambio climático en los ecosistemas semiáridos que se están llevando en las instalaciones del Campus de Móstoles y la Estación Experimental de Aranjuez, donde de manera experimental se están simulando las condiciones de temperatura (aumento de 2.5 ºC anuales) y precipitación (reducción de un 30% de la cantidad total de precipitación) predichas por los modelos de cambio climático para las zonas semiáridas de la Península Ibérica. Asimismo, los alumnos también participarán en las medidas que se están realizando en estos experimentos (mediciones de humedad del suelo y de fotosíntesis/respiración, medidas fisiológicas y de crecimiento, etc), la toma de muestras de suelo y preparación de las mismas para su análisis en el laboratorio (análisis fisico-químicos y moleculares basados en el uso de ADN). 

Si quieres ver el tipo de investigación que hacemos en nuestro grupo puedes echar un vistazo a este vídeo realizado por la UPCA de la URJC:

 Vista de las instalaciones del Campus de Móstoles donde estamos realizando nuestros experimentos de cambio climático.

Parcela experimental en la Estación Experimental de Aranjuez

Estas colaboraciones son totalmente compatibles con el normal desarrollo de las actividades académicas, y el horario es adaptable a las necesidades de los alumnos. Si deseas más información sobre cómo colaborar con nosotros y las actividades a realizar contacta con Victoria Ochoa o Beatriz Gozalo.

martes, 5 de julio de 2016

We are looking for a candidate for a post-doctoral competitive call

We are looking for a motivated candidate to apply to a competitive call from the Regional Government of Madrid for funding a 4-yr post-doctoral contract to work in our lab. The requeriments of the candidates are the following:

* Strong publication record in any of the areas related to the research we do in the lab (for details about we do and recent publications check our webpage). We are particularly interested in candidates with expertise in microbial ecology, bioinformatics or remote sensing.
* The candidate should hold a PhD awarded between 1 January 2013 and 20 June 2016
* The candidate should have been working (under a contract or fellowship, proof required) outside Spain for at least one of the last two years.

Please note that this is not a job offer, as the candidate will apply to a competitive call (a total of 25 contracts will be awarded for all knowledge areas). All the details of this call (in Spanish) can be found here. If awarded, the person would work in the Dryland Ecology and Global Change Lab, located in the Móstoles Campus of Rey Juan Carlos University. He/she would be part of the research team working in the BIODESERT project, awarded to Fernando T. Maestre by the Consolidator Grant program of the European Research Council for the period 2016-2020.

Interested candidates in apply to one of these contracts in the lab should send their updated CV and two references to Fernando T. Maestre before 10 July 2016. The selected applicant will be notified on 11 July, and will need to prepare all the materials requested by the call (the candidate will apply to "Modalidad 2") by 15 July (sorry for the short notice).

miércoles, 4 de mayo de 2016

Juan Gaitán succesfully completes his PhD!

Juan Gaitán, a researcher form INTA in Argentina who has been a graduate student in the lab for the past four years, has succesfully completed his PhD, which will be defended soon in the Faculty of Agronomy of the University of Buenos Aires. The title of his PhD is "Structural and functional attributes of arid and semiarid ecosystems of Patagonia and its relation with abiotic factors and the anthropic use" and the abstract of this PhD is:

The advance of desertification is one of the major environmental problems affecting the Argentinian Patagonia. Overgrazing and recurrent droughts are the main drivers of desertification in this region. According to climate models, the occurrence of drought will increase in the future in drylands worldwide, including those from Patagonia. However, little is known on the mechanisms and interactions of climate change and desertification, and how they will affect the ecosystems of the Patagonian steppe. A better understanding of these aspects can help to monitor desertification processes, project their changes and assess their impact under climate change. The objective of this thesis was to analyze the relationship between structural and functional attributes of ecosystems and their interaction with climate and anthropogenic use (grazing) in dryland ecosystems from Argentinian Patagonia. The study was conducted on 320 sites of the MARAS (acronym of “Monitoreo Ambiental para Regiones Áridas y Semiáridas”) network, installed and maintained by INTA researchers since 2007. The main findings found were: The NDVI index derived from MODIS sensor is a good estimator of structural (plant cover) and functional (surrogates of soil functioning) attributes of ecosystems. Vegetation structural attributes such as species richness and cover explained a significant and unique portion of the variability found in ecosystem functioning at the regional scale, which is as important as that explained by climate. The occurrence of drought causes a decrease in the primary productivity of ecosystems, which is higher as temperatura and drought severity increase. Drought effects were attenuated in those sites having higher species richness and shrub cover. Species richness and grass cover (especially palatable species) had a positive effect on functional attributes of the ecosystem such as primary productivity and precipitation-use efficiency. Grazing decreased species richness and thecover of palatable grasses, increased the cover of unpalatable grasses and did not promote shrub encroachment. The effects of grazing on the structure and functioning of ecosystems converged with the expected effects induced by warming and increasing aridity due to ongoing global climate change.

The PhD has four chapters, and three of them have already been published (two of the articles are Open Access):

Gaitán, J.J., D. Bran, G. Oliva, F.T. Maestre, M. R. Aguiar, Esteban G. Jobbágy, G. Buono, D. Ferrante, V. Nakamatsu, G. Ciari, J. Salomone, V. Massara. 2014. Plant species richness and shrubcover attenuate drought effects on ecosystem functioning across Patagonianrangelands. Biology Letters 10, 20140673.
Gaitán, J.J., D. Bran, G. Oliva, F.T. Maestre, M. R. Aguiar, E.G. Jobbágy, G. Buono, D. Ferrante, V. Nakamatsu, G. Ciari, J. Salomone, V. Massara. 2014. Vegetation structure is as important as climate for explainingecosystem function across Patagonian rangelandsJournal of Ecology 102: 1419-1428.
Gaitán, J.J., D. Bran, G. Oliva, G. Ciari, V. Nakamatsu, J. Salomone, D. Ferrante, G. Buono, V. Massara, G. Humano, D. Celdrán, W. Opazo, F.T. Maestre. 2013. Evaluating the performance ofmultiple remote sensing indices to predict the spatial variability of ecosystemstructure and functioning in Patagonian steppesEcological Indicators 34: 181–191.
Gaitán, J.J., D. Bran, G. Oliva, F.T. Maestre, M.R. Aguiar, G. Buono, D. Ferrante, V. Nakamatsu, G. Ciari, J.M. Salomone, V. Massara, G. García Martinez. Warming and overgrazing have convergent effects on ecosystem structure and functioning in Patagonian rangelands. Under review

Many congrats Juan! We are all very happy of what you have acomplished in your PhD!

jueves, 21 de abril de 2016

Latest accepted article from the lab (April 2016)

A new paper from our global dryland database has just been accepted. It results from a collaboration with Prof. Werner Ulrich from Nicolaus Copernicus University. It will be published online early during the next weeks/months, but here go the abstracts:

Ulrich, W., S. Soliveres, A. Thomas, A. Dougill & F. T. Maestre. 2016. Environmental correlates of species rank – abundance distributions in global drylands. Perspectives in Plant Ecology, Evolution and Systematics   

Theoretical models predict lognormal species abundance distributions (SADs) in stable and productive environments, with log-series SADs in less stable, dispersal driven communities. We studied patterns of relative species abundances of perennial vascular plants in global dryland communities to: i) assess the influence of climatic and soil characteristics on the observed SADs, ii) infer how environmental variability influences relative abundances, and iii) evaluate how colonisation dynamics and environmental filters shape abundance distributions. We fitted lognormal and log-series SADs to 91 sites containing at least 15 species of perennial vascular plants. The dependence of species relative abundances on soil and climate variables was assessed using general linear models. Irrespective of habitat type and latitude, the majority of the SADs (70.3%) were best described by a lognormal distribution. Lognormal SADs were associated with low annual precipitation, higher aridity, high soil carbon content, and higher variability of climate variables and soil nitrate. Our results do not corroborate models predicting the prevalence of log-series SADs in dryland communities. As lognormal SADs were particularly associated with sites with drier conditions and a higher environmental variability, we reject models linking lognormality to environmental stability and high productivity conditions. Instead our results point to the prevalence of lognormal SADs in heterogeneous environments, allowing for more even plant communities or in stressful ecosystems, which are generally shaped by strong habitat filters and limited colonisation. This suggests that drylands may be resilient to environmental changes because the many species with intermediate relative abundances could take over ecosystem functioning if the environment becomes suboptimal for dominant species.

martes, 8 de marzo de 2016

Recently accepted articles from the lab (March 2016)

Two new papers from the lab have been accepted during the last weeks. They include a meta-analysis evaluating biogeographical patterns and drivers of bacterial diversity in terrestrial ecosystems at the global scale, led by Manuel Delgado-Baquerizo and resulting from a collaboration with the group of Prof. Brajesh Singh at the Hawkesbury Institute for the Environment on last year, and another paper from the climate change experiments that we are maintaining at the Aranjuez Experimental Station, led by Guadalupe León Sánchez and resulting from a collaboration with the group of José I. Querejeta at CEBAS-CSIC. They will be published online early during the next weeks/months, but here go the abstracts:

Delgado-Baquerizo, M., F. T. Maestre, P. B. Reich, P. Trivedi, Y. Osanai, Y. Liu, K. Hamonts, T. Jeffries & B. K. Singh. Carbon content and climate variability drive global soil bacterial diversity patterns. Ecological Monographs 

Despite the vital role of microorganisms for ecosystem functioning and human welfare, our understanding of their global diversity and biogeographical patterns lags significantly behind that of plants and animals. We conducted a meta-analysis including ~600 soil samples from all continents to evaluate the biogeographical patterns and drivers of bacterial diversity in terrestrial ecosystems at the global scale. Similar to what has been found with plants and animals, the diversity of soil bacteria in the Southern Hemisphere decreased from the equator to Antarctica. However, soil bacteria showed similar levels of diversity across the Northern Hemisphere. The composition of bacterial communities followed dissimilar patterns between hemispheres, as the Southern and Northern Hemispheres were dominated by Actinobacteria and Proteobacteria/Acidobacteria, respectively. Moreover, we found a decrease in soil bacterial diversity with altitude. Climatic features (e.g. high diurnal temperature range and low temperature) were correlated with the lower diversity found at high elevations, but geographical gradients in soil total carbon and species turnover were important drivers of the observed latitudinal patterns. We thus found both parallels and differences in the biogeographical patterns of above- versus soil bacterial diversity. Our findings support previous studies that highlighted soil pH, spatial influence and organic matter as important drivers of bacterial diversity and composition. Furthermore, our results provide a novel integrative view of how climate and soil factors influence soil bacterial diversity at the global scale, which is critical to improve ecosystem and earth system simulation models and for formulating sustainable ecosystem management and conservation policies. Our findings contribute to fill important gaps in our understanding of the patterns and drivers of soil microbial diversity at the global scale, and can be of paramount utility for future studies to come 

León-Sánchez, L., E. Nicolás, P. A. Nortes, F. T. Maestre & J. I. Querejeta. Photosynthesis and growth reduction under warming are driven by non-stomatal limitations in a Mediterranean semiarid shrub. Ecology and Evolution 

Whereas warming enhances plant nutrient status and photosynthesis in most terrestrial ecosystems, dryland vegetation is vulnerable to the likely increases in evapotranspiration and reductions in soil moisture caused by elevated temperatures. Any warming-induced declines in plant primary production and cover in drylands would increase erosion, land degradation and desertification. We conducted a four-year manipulative experiment in a semiarid Mediterranean ecosystem to evaluate the impacts of a ~2ºC warming on the photosynthesis, transpiration, leaf nutrient status, chlorophyll content, isotopic composition, biomass growth and post-summer survival of the native shrub Helianthemum squamatum. We predicted that warmed plants would show reduced photosynthetic activity and growth, primarily due to the greater stomatal limitation imposed by faster and more severe soil drying under warming. On average, warming reduced net photosynthetic rates by 36% across the study period. Despite this strong response, warming did not affect stomatal conductance and transpiration. The reduction of peak photosynthetic rates with warming was more pronounced in a drought year than in years with near-average rainfall (75% and 25-40% reductions relative to controls, respectively), with no indications of photosynthetic acclimation to warming through time. Warmed plants had lower leaf N and P contents, chlorophyll a:b ratios, δ13C and sparser and smaller leaves than control plants. Warming reduced shoot dry mass production by 31%. However, warmed plants were able to cope with large reductions in net photosynthesis, leaf area and biomass production without changes in post-summer survival rates. Our findings highlight the key role of non-stomatal factors (biochemical and/or nutritional) in reducing net carbon assimilation rates and growth under warming, which has important implications for projections of plant carbon balance under the warmer and drier climatic scenario predicted for drylands worldwide. Moderate warming exerted negative effects on the leaf nutrient status, net photosynthetic rate and shoot biomass growth of H. squamatum, especially (but not only) during dry periods. Our findings indicate that projected climate warming could reduce net primary production by about one-third and potentially alter other key ecological processes (through changes in leaf N and P) such as plant-herbivore relationships, litter decomposition and nutrient cycling in semiarid gypsum shrublands dominated by H. squamatum.

jueves, 4 de febrero de 2016

News related to our Nature Communications article

We have recently published in NatureCommunications the article “Microbial diversity drives multifunctionality in terrestrial ecosystems”, led by Manuel Delgado-Baquerizo. This article, which results from the research we have carried out in the framework of the BIOCOM project, is being disseminated by newspapers, blogs and scientific news outlets. This is a collaboration with the members of the EPES-BIOCOM network and with the group of Prof. Brajesh Singh from the University of Western Sydney, where Fernando conducted a research stay between February and May 2015. Below we compile the different press releases and news that have been published and that mention this article. We will be updating this entry as new news item are being published. 

Press Releases

News in newspapers and webpages & interviews

Spain and Latin America (in Spanish)

Rest of the world (in English)