The Patterns of climate change

Biologists analyze data of long-term experiment to monitor and predict how plant species will respond to climate change

Plant Ecology researchers at the University of Tübingen have developed a technique to monitor and predict how plant species will respond to climate change. Dr. Mark Bilton and Professor Katja Tielbörger, from the Institute of Evolution and Ecology, re-analysed data with Spanish collaborators from their unprecedented 16-year experiment. The experiment was conducted in an area the size of two football pitches within the Garraf National park south west of Barcelona. The landscape is mostly a Mediterranean scrubland, featuring thickets of low rise shrubs and herbs such as rosemary and thyme, and home to many protected species.

Using large automatic shelters, climate for the plants living in their natural environment was changed in order to match climate conditions predicted in the future, separately by decreasing rainfall and by raising temperatures. However, until now, it was unclear how the different species of plants were responding to changed climate, making it difficult to make further predictions about which species may be most affected in the future. The results of the study were published in the New Phytologist.

In general, global warming and reduced precipitation may lead to large-scale species losses and vegetation shifts in ecosystems around the world. Depending on whether plants are better adapted to warm and dry conditions or to cool and wet conditions, the response to a changed climate is likely to vary even within a region. In the study the scientists showed, that within a region, the relative rate and direction of plant response to a changed climate can be directly related to where and which climates the species occur in more frequently.

Therefore the researchers used a large online database containing the localities of where the different species in the experiment occurred all throughout southern Europe. These observations were combined with rainfall and temperature maps. This way the average temperature or rainfall requirements of the different co-occurring species in Spain could be used to rank them, based on which climates they are more commonly found. This ranking technique helped the scientists unlock the secrets behind which species were changing in the experiment, and monitor their changes over time.

In this particular experiment, the overall species diversity and vegetative biomass did initially respond negatively, but from 8 to 16 years the overall amount of vegetation was increasing again. Here the researchers showed that the initial decrease was due to a disappearance of the wet adapted species, followed by a delayed increase in the dry loving species. In addition, the novel ranking technique showed, that the species that declined under decreased rainfall, were different to those disappearing under increased temperatures.

By finding that responses were mainly related directly to where the species originally occur more frequently, separately for either rainfall or temperature, predictions can be extended to other future scenarios of climate change. “The technique is logical, but also surprisingly revealing”, says Dr. Mark Bilton, who has been using the same method to study plant responses in Israel. “It allows us to compare the rate of change of species within a habitat, but also between habitats”. Combining the ranking technique with the leading experimental approach to understanding climate change responses, the response of vegetation in other regions can be monitored and compared. “Within a region this can aid conservation efforts to identify those species likely to be lost most quickly. We are also confident it can help identify, which species and regions around the world may be more vulnerable to climate change in the future.”

 

Climate Change_Ecology and Evolution  xxxx Climate Change_Ecology and Evolution2

Automatic shelters used to alter either precipitation or temperature in Garraf National Park near Barcelona. Images: Courtesy of Josep Peñuelas

Publication: Daijun Liu, Josep Penuelas, Roma Ogaya, Marc Estiarte, Katja Tielbörger, Fabian Slowik, Xiaohong Yang and Mark C. Bilton: Species selection under long-term experimental warming and drought explained by climatic distributions, New Phytologist , DOI: 10.1111/nph.14925, http://onlinelibrary.wiley.com/doi/10.1111/nph.14925/full

Contact: Daijun Liu, Prof. Josep Peñuelas, Universitat Autònoma de Barcelona, CREAF – Global Ecology Unit, Phone +34 667094190, d.liu@creaf.uab.es

Dr. Mark Bilton, Tübingen University, Institute of Evolution and Ecology, Phone +49 7071 29-73235, mark.bilton@uni-tuebingen.de

 

Nature commends four Spanish scientists for outstanding mentoring

Four Spanish scientists have been recognised by Nature, the leading, international weekly journal of science, for exemplary personal mentoring of other scientists. The Nature Awards for Mentoring in Science have been hosted since 2005 in various countries and regions to champion the importance of mentoring and inspiring a generation of young scientists. The 2017 awards have for the first time taken place in Spain.

Chair of the judges: Josep Penuelas, Center for Ecological Research and Forestry Applications (CREAF) – National Research Council (CSIC), Barcelona

Judging panel:
Alison Abbott, Nature, Munich, Germany
Emilia R. Solano, CIEMAT, Madrid, Spain
Juan Lerma, Instituto de Neurociencias de Alicante – UMH, Alicante, Spain
Mariano Barbacid, Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
Pilar Ruiz Lapuente, Institute of Cosmos Sciences, University of Barcelona, Barcelona, Spain

At the ceremony held at the Spanish Royal Academy of Sciences in Madrid, Sir Philip Campbell PhD, the Editor-in-Chief of Nature, presented the awards and congratulated the recipients on their laudable contributions.

The joint-recipients of the lifetime achievement award are:

  • Professor Carlos Belmonte, founding Director of the Institute of Neuroscience of Alicante
  • Professor Margarita Salas, former Director of the CSIC Centre for Molecular Biology Severo Ochoa in Madrid

 

The joint-recipients of the mid-career achievement award are:

  • Professor Carlos López-Otín, a molecular biologist from the University of Oviedo
  • Professor Lluís Torner, a physicist and founding Director of the ICFO (Institute of Photonic Sciences) in Barcelona.

 

Carmen Vela, the Spanish Secretary of State for Research, Development and Innovation commented on the importance of the awards: “Nature is an internationally renowned science journal in which researchers from around the world seek to publish their work, so it is very important for us to receive the ‘Nature Mentoring Awards’ here this year. Spain is a country full of talented scientists, and many of them have been guided by Margarita Salas, Carlos Belmonte, Carlos López-Otín and Lluis Torner, four great Spanish researchers. I would like to express my gratitude for their work over these years”.

Sir Philip Campbell, who established the awards, said: “These awards have taken place in 13 countries or regions, including the western United States, Nordic countries, South Africa, Japan and China. These are very varied cultures, and yet the key characteristics of outstanding mentors are remarkably similar. Spain’s great examples are no exception – they are extraordinary in their ability to nurture emerging scientists of great diversity.”

Through the Nature Awards for Mentoring in Science Nature recognises outstanding scientific mentors in different regions around the world. Each winner receives a prize of €5,000.

More information about the panel of judges and eligibility criteria for this year’s awards can be found here.

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Mapping local and global variability in plant trait distributions

Butler_et al_PNAS_2017.tif
Specific leaf area (SLA), and dry mass-based concentrations of leaf nitrogen (Nm) and phosphorus (Pm) are used in this study to better capture the response of the land surface component of the Earth System to environmental change. Image: Butler, E.E., et al. 2017. Proceedings of the National Academy of Sciences

 

Our ability to understand and predict the response of ecosystems to a changing environment depends on quantifying vegetation functional diversity. However, representing this diversity at the global scale is challenging. Typically, in Earth Systems Models, characterization of plant diversity has been limited to grouping related species into Plant Functional Types (PFTs), with all trait variation in a PFT collapsed into a single mean value that is applied globally.

In a new study in the journal Proceedings of the National Academy of Sciences authors created fine-grained global maps of plant trait distributions that can be applied to Earth System Models by using the largest global plant trait database and state of the art Bayesian modeling. “Here, we use an updated version of the largest global database of plant traits coupled with modern Bayesian spatial statistical modeling techniques to capture local and global variability in plant traits. This combination allows the representation of trait variation both within pixels on a gridded land surface as well as across global environmental gradients”, said Dr. Butler from Department of Forest Resources, University of Minnesota.

Focusing on a set of plant traits closely coupled to photosynthesis and foliar respiration – specific leaf area (SLA), and dry mass-based concentrations of leaf nitrogen (Nm) and phosphorus (Pm), authors characterize how traits vary within and among over 50,000 ~ 50 × 50 km cells across the entire vegetated land surface. “The importance of these traits (SLA, Nm, Pm) and the more advanced representation of functional diversity developed here may be used to better capture the response of the land surface component of the Earth System to environmental change”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

This endeavor advances prior trait mapping by generating global maps that preserve variability across scales by using modern Bayesian spatial statistical modeling in combination with a database over three times larger than previous analyses. “Our maps reveal that the most diverse grid cells possess trait variability close to the range of global PFT means”, said Dr. Butler from Department of Forest Resources, University of Minnesota.

 

Journal Reference: Butler, E.E., Datta, A., Flores-Moreno, H., Chen, M., Wythers, K.R., Fazayeli, F., Banerjee, A., Atkin, O.K., Kattge, J., Amiaud, B., Blonder, B., Boenisch, G., Bond-Lamberty, B., Brown, K.A., Byun, C., Campetella, G., Cerabolini, B.E.L., Cornelissen, J.H.C., Craine, J.M., Craven, D., de Vries, F.T., Díaz, S., Domingues, T., Forey, E., Gonzalez, A., Gross, N., Han, W., Hattingh, W.N.,  Hickler, T., Jansen, S., Kramer, K., Kraft, N.J.B., Kurokawa, H., Laughlin, D.C., Meir, P., Minden, V.,  Niinemets, Ü., Onoda, Y., Peñuelas, J., Read, Q., Valladares Ros, F., Sack, L., Schamp, B.,  Soudzilovskaia, N.A., Spasojevic, M.J., Sosinski, E., Thornton, P., van Bodegom, P.M.,  Williams, M., Wirth, C., Reich, P.B.. 2017. Mapping local and global variability in plant trait distributions. Proceedings of the National Academy of Sciences.

Microbial mass movements

Flying aircrafts_ESA_Sept2017
Global transport, tourism, waste disposal have changed biogeographic patterns for microorganisms. In this study authors point to the importance of the dispersal of cells and genes by human activities. The picture presents a flight map showing 15,000 simultaneously flying aircrafts based on 25 million positions (European Space Agency (ESA)).

 

For several billion years, microorganisms and the genes they carry have mainly been moved by physical forces such as air and water currents. These forces generated biogeographic patterns for microorganisms that are similar to those of animals and plants.

In a new study in the journal Science authors note that humans and animals now move on an unprecedented scale, and this movement actively transports and enriches a specific subset of microorganisms.

“Humans in the past 100 years have changed these natural dynamics by transporting large numbers of cells to new locations through waste disposal, tourism, and global transport and by modifying selection pressures at those locations. As a consequence, we are substantially altering microbial biogeography”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

Dissemination through wastewater

Wastewater carries high densities of microorganisms and their cargo genes. It should be noted that, globally, some 359,000 km2 of croplands depend on irrigation with urban wastewater, 80% of which undergoes little or no treatment. Therefore, the use of wastewater or manure in agriculture contaminates fruits, vegetables, and farm animals which in turn are distributed globally. Wastewater also contains pollutants with biological effects (as metals, antibiotics or disinfectants). These compounds stimulate bacterial stress response systems that increase mutation rates which, in turn, confer adaptive advantages on at least a subset of cells arriving at a new location.

For a sense of the importance of this adaptive advantage, authors consider the clinical class 1 integron. This DNA element acquires foreign genes from the environment and has played a central role in spreading antibiotic resistance among bacterial pathogens. DNA sequencing data show that it had the origin in a single cell, in the early 20th century. Millions to billions of copies of this element now exists in every gram of feces from human and domestic animals. This remarkable increase in its abundance and distribution has been driven by antibiotic selection, increases in human population, and dissemination via global transport.

The role of human and material movement

This study points out that humans and agricultural animals now comprise 35 times as much biomass as wild terrestrial mammals. The bacteria shed in feces, therefore, mainly represent the gut microbiota of humans and agricultural animals (cattle, sheep, goats, pigs, and chickens) and they have vastly increased in both abundance and distribution, particularly in the last century. “Efficiency of dispersal is enhanced by the 1.2 billion international tourist movements per year, as evidenced by the rapid spread of bacterial clones and antibiotic resistance genes between continents”, emphasizes Prof. Micahel Gillings from Macquarie University, Sydney .

The study also points out that humans additionally promote dispersal of microbial cells via mass movement of materials. In this regard it should be noted that human activities now move more soil, sand, and rock than all natural processes combined. As an example, natural fluvial erosion is 21 gigatons (Gt) per year, much lower than the75 Gt per year eroded by agriculture. “This erosion transports very large numbers of bacteria, given that soil can contain more than a billion microbial cells per gram. Movements on this scale have consequences for human health, agriculture, and ecosystem functions, such as increasing the spread of human pathogens and threatening sustainable food productivity”, said Prof. Yong-Guan Zhu from Chinese Academy of Science.

Changes to biogeochemical cycles

According to this study, changes in the distribution and abundance of microorganisms, and the resultant changes in microbial ecosystems will affect biogeochemical cycles driven by microbial activity. “Knowledge of the connections between microbial biodiversity and landscape-scale biogeochemical processes, as well as below-ground ecosystems, will be essential to predict the magnitude and direction of these changes”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

Linking the rapidly expanding databases generated by environmental genomics with biogeochemical models could reveal changes in nutrient cycles. “This fusion of genomics and Earth system science is a first step to understanding how the biochemical functions of microorganisms could be altered, temporally and spatially, by global change”, said Prof. Yong-Guan Zhu from Chinese Academy of Science.

Unlocking the complexity

There is a recent growing trend for monitoring the environmental dissemination of genes, particularly those that confer phenotypes of direct relevance to human and animal health. In this sense, Prof. Josep Peñuelas points to the high importance of understanding how human activities cause systematic changes in ecosystems and highlight the priority of investigating microbial invasions, microbial extinctions, and perturbations to microbial ecosystems.

 

Journal Reference: Zhu, Y.G., Gillings, M., Simonet, P., Stekel, D., Banwart, S., Penuelas, J. 2017. Microbial mass movements. Science 357 (6356), 1099-1100.

Nature Mentoring Awards for Mentoring in Science 2017 – Spain

The Jury for the Nature Mentoring Awards for Mentoring in Science 2017 has met in CREAF (Bellaterra, Catalonia, Spain) on Spetember 15th, 2017.

The jury, headed by Prof. Josep Penuelaswas made up for the following experts:

  • Alison Abbott, Senior European Correspondent of Nature journal, Munich
  • Emilia Solano, CIEMAT, Madrid, Spain
  • Pilar Ruiz Lapuente, Institute of Cosmos Sciences, University of Barcelona, Barcelona, Spain
  • Juan Lerma, Instituto de Neurociencias de Alicante – UMH, Alicante, Spain
  • Mariano Barbacid, Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
  • Josep Penuelas, CSIC-CREAF, Barcelona, Spain

 

Meeting CREAF_15092017

Shifting from a fertilization-dominated to a warming-dominated period

Penuelas_Nature_Shifting_Sept2017
In a new study in the journal Nature Ecology and Evolution researchers argue that a slowdown of the CO2 and N fertilization effects on ecosystem carbon sequestration and the rapid emergence of negative ecosystem impacts from global climate change might drive a change from a fertilization-dominated to a warming-dominated period. Photos by Pixabay

 

Natural ecosystems currently remove on average each year an amount of carbon dioxide equivalent to about one third of human-caused carbon dioxide (CO2) emissions from fossil fuel burning and cement production. There are numerous evidences which show that the efficiency of natural land ecosystems to absorb the increasing fossil fuel and cement emissions does not keep their path.

In a new study in the journal Nature Ecology and Evolution authors hypothesize that the progressive long term weakening of the natural land sink relative to fossil fuel CO2 emissions marks the beginning of a transition from a vegetation fertilization-dominated period to a period dominated by nutrient and climate constraints on plant growth, and larger climate change impacts (e.g., heatwaves).

There are many unknowns in the timing of this transition, so in light of the recent Paris COP21 agreement, a better understanding of climate change impacts on carbon stocks remains paramount to understand the level of climate mitigation required to achieve agreed temperature goals, indicates Prof Josep Peñuelas from CREAF-CSIC Barcelona.

Human fertilization changes productivity and carbon residence in ecosystems

Human activities result in increasing atmospheric concentrations of CO2, N inputs to ecosystems and temperature. This leads to enhanced metabolism of organism and lengthening the growing seasons. Plants can consequently grow more. The magnitude of carbon sinks and their duration depend both on the rate of increase of carbon inputs and on the residence time of the carbon being taken up by ecosystems explain Drs Shilong Piao from Academy of Sciences in Pekin and Jordi Sardans from CREAF in Barcelona.

Authors point out that several studies realized at global scale, in all biomes, suggest that trends of increasing sinks may be slowing down. A remaining question is whether in regions where carbon sinks may be slowing down, this is due to stalling productivity or to reducing residence times.

Likely limitations for enhancement of carbon sinks

The anthropogenic increases in CO2 and atmospheric nitrogen deposition are not matched by a similar increase in the inputs of other key nutrients such as phosphorus (P) and/or potassium (K). Current evidence suggests an overall shortage of P which will act as a limiting factor to meet the increasing demand for plant growth. “A better understanding of the factors that regulate exchanges between pools of “available” and “unavailable” soil P is critically needed”, said Prof. Ivan Janssens from University of Antwerp.

The higher nocturnal temperatures enhance night respiration, Prof. Josep Canadell pointed out. Moreover, severe regional heatwaves are also likely to become more frequent in a changing climate, and their negative impact on terrestrial carbon sequestration may thus also become important. “For example, the 2003 heatwave decreased European gross primary productivity by 30%, which resulted in a strong anomalous net source of carbon dioxide to the atmosphere; this effect is the equivalent of reversing four years of net ecosystem carbon sequestration in the European continent”, said Prof. Philippe Ciais from LSCE Paris.

In recent decades large-scale droughts have reduced seasonal NPP in the Southern and Northern hemispheres and weakened the terrestrial carbon sink. However, as Drs Marcos Fernandez-Martinez and Jofre Carnicer from CREAF-CSIC Barcelona point out, there is an inherent difficulty in quantifying the response of NPP to drought because it depends on the timing of drought during the growing season, and on ecosystem properties of resistance to drought.

Furthermore, it should be taken into account that most land use changes, fires, and harvests, which are expected to increase in the future reduce residence times, thereby reducing the sink capacity of the land biosphere as noticed by Prof Michael Obersteiner from IIASA Vienna.

Due to the above, the potential saturation or slower increase of the sink capacity of terrestrial ecosystems, or even its transition into a source of CO2, could be expected. Moreover, for Prof. Josep Peñuelas from CREAF-CSIC Barcelona, current climate models do not necessarily well represent extreme events due to coarse resolution (eg. extreme precipitation, wind storms and tropical cyclones) or to insufficiently constrained soil-atmosphere interactions. At this point, authors point out that these models could improve its prediction capacity through the addition of factors outlined above. “Such improved models could then help understanding the responses to different levels of global warming (especially in the range 1.5-3°C according to the Paris agreement and current intended policies)”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

Shift from a fertilization to a warming period

This study presents multiple evidences suggesting limits to the buffering capacity of the biosphere. Thus, Prof. Josep Peñuelas indicates that a slowdown of the CO2 and N fertilization effects on ecosystem carbon sequestration and the rapid emergence of negative ecosystem impacts from global climate change might drive a shift from an Anthropocene period dominated by fertilization to another period characterized by saturated fertilization and strong climate change.

For Prof. Peñuelas, although the climate has not yet changed dramatically in the Anthropocene, the coming decades will undoubtedly be different. Prof. Vautard from LSCE Paris explains that “A warming of 2 °C would slightly increase the frequency of 2003-like heatwaves in Northern France, but a warming of 3 °C would instead produce very different conditions, with one summer like that of 2003 occurring every three or four years, which would therefore affect the forests carbon sink in Europe much more than in the past”.

There is also the possibility of low probability but high impact phenomena which would lead to rapid positive feedbacks to the climate system (e.g. massive dieback of Amazon rainforest because of reduced rainfall or a dramatic temperature drop in the North Atlantic because of the collapse of the ocean current). “The occurrence of this phenomena is highly uncertain, particularly for low temperature scenarios. However, it is much more certain that we are currently entering a new warming period where ecosystems are put under increasing stresses”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

This study was funded by the European Research Council Synergy grant ERC-2013-SyG-610028

Journal Reference: Peñuelas, P., Ciais, P., Canadell, J., Janssens, I., Fernandez-Martinez, M., Carnicer, J., Obersteiner, M., Piao, S., Vautard, R., Sardans, J. 2017. Shifting from a fertilization-dominated to a warming-dominated period. Nature Ecology and Evolution.