Elevated tropospheric ozone concentrations induce adverse effects in plants. We reviewed how ozone affects (i) the composition and diversity of plant communities by affecting key physiological traits; (ii) foliar chemistry and the emission of volatiles, thereby affecting plant-plant competition, plant-insect interactions, and the composition of insect communities; and (iii) plant-soil-microbe interactions and the composition of soil communities by disrupting plant litterfall and altering root exudation, soil enzymatic activities, decomposition, and nutrient
cycling. The community composition of soil microbes is consequently changed, and alpha diversity is often reduced.

The effects depend on the environment and vary across space and time. We suggest that Atlantic islands in the Northern Hemisphere, the Mediterranean Basin, equatorial Africa, Ethiopia, the Indian coastline, the Himalayan region, southern Asia, and Japan have high endemic richness at high ozone risk by 2100.

Reference: Agathokleous, E., Feng, Z., Oksanen, E., Sicard, P., Wang, Q., Saitanis, C.J., Araminiene, V., Blande, J.D., Hayes, F., Calatayud, V., Domingos, M., Veresoglou, S.D., Peñuelas, J., Wardle, D.A., De Marco, A.D., Li, Z., Harmens, H., Yuan, X., Vitale, M., Paoletti, E. 2020. Ozone affects plant, insect, and soil microbial communities: A threat to terrestrial ecosystems and biodiversity. Science Advances, 6(33): eabc1176. Doi: 10.1126/sciadv.abc1176

Un equip internacional –amb l’investigador del CSIC al CREAF Josep Peñuelas– explora els factors decisius del comportament vegetal i com incloure’ls als models predictius. El resultat es publica a Nature Plants i vol millorar la comprensió del cicle global del carboni i els serveis ecosistèmics i el seu futur si els boscos canvien pel canvi climàtic. 

Bosc de coníferes. Public Domain.

“Hem demostrat que si representem els principis d’evolució, autoorganització i maximització d’entropies (l’organització aleatòria d’alguns processos naturals) en els models,  podrem predir millor el comportament de les plantes complexes i la vegetació en general en relació amb els canvis ambientals”, explica Josep Peñuelas.

Aquests factors ja s’han utilitzat anteriorment per separat per entendre aspectes concrets del funcionament de les plantes. Però les implicacions que tenen quan es combinen encara no s’havien analitzat a fons. Aprofundir-hi és important per conèixer millor com afectarà el canvi climàtic a aquestes dinàmiques. 

Podeu llegir la investigació Organizing principles for vegetation dynamics a l’article que ha elaborat l’International Institute for Applied Systems Analysis, l’institut austríac que l’ha liderat.

Article de referència:

Franklin O, Harrison S, Dewar R, Farrior C, Brännström A, Dieckmann U, Pietsch S, Falster D, Penuelas J, et al. (2020). Organizing principles for vegetation dynamics. Nature Plants DOI: 10.1038/s41477-020-0655-x

Font: Blog CREAF
http://blog.creaf.cat/noticies/entendre-funcionament-vegetacio-planeta/

Un equip d’investigació internacional on ha participat en Josep Peñuelas explora els factors que més afecten el comportament de les plantes i com es poden incloure als models predictius per perfeccionar-los. L’estudi, publicat a Nature Plants, vol millorar la comprensió del cicle global del carboni i els serveis ecosistèmics i quin futur els espera si els boscos canvien davant el canvi climàtic. 

Bosc de coníferes. Public Domain.

“Hem trobat que si representem els principis d’evolució, autoorganització i maximització d’entropies (l’organització aleatòria d’alguns processos naturals) en els models,  podrien predir millor el comportament de les plantes complexes, i la vegetació en general, en relació amb els canvis ambientals”, explica en Josep Peñuelas, investigador del CSIC al CREAF.

Aquests factors que proposa l’estudi ja s’han utilitzat anteriorment per separat per entendre aspectes concrets del funcionament de les plantes, però les implicacions que tenen quan es combinen encara no s’havien entès del tot. Profunditzar-hi és important per conèixer millor com afectarà el canvi climàtic a aquestes dinàmiques. 

Podeu llegir més sobre la recerca en l’article que ha preparat  l’IIASA, institució austríaca líder d’aquesta.

Article de referència 

Franklin O, Harrison S, Dewar R, Farrior C, Brännström A, Dieckmann U, Pietsch S, Falster D, Penuelas J, et al. (2020). Organizing principles for vegetation dynamics. Nature Plants DOI: 10.1038/s41477-020-0655-x

Font: Blog CREAF

Afforestation is considered an effective strategy for increasing carbon sequestration and mitigating climate change and it has undoubtedly increased C stored in biomass. Afforestation has been widely implemented in many countries since the 1990s, increasing the area of planted forests globally by about 1.05 × 108 ha Picture by Pixabay

Afforestation is the term used to refer the establishment of forests where previously there have been none, or where forests have been missing for a long time and has been proposed as an efficient method for removing carbon dioxide and mitigating climate change. The success of the goals of mitigation, however, depends on both the area of trees planted and the potential for carbon (C) sequestration of each afforestation. However, afforestation-induced changes in soil organic C (SOC) are poorly quantified due to the paucity of large-scale sampling data.

In a new study published in the journal Nature plants authors provide the first comprehensive assessment of the afforestation impact on SOC stocks with a pairwise comparative study of samples from 619 control-and-afforested plot pairs in northern China.

Authors found context-dependent effects of afforestation on SOC: afforestation increases SOC density (SOCD) in C-poor soils but decreases SOCD in C-rich soils, especially in deeper soil. Thus, the fixed biomass/SOC ratio assumed in previous studies could overestimate the SOC enhancement by afforestation. “By extrapolating the sampling data to the entire region, we estimate that afforestation increased SOC stocks in northern China by only 234.9 ± 9.6 TgC over the last three decades. The study highlights the importance of including pre-afforestation soil properties in models of soil carbon dynamics and carbon sink projections” explained Dr. Hong from the Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, China.

The results of the study strongly suggest that estimated afforestation C sink potentials that do not account for background soil C stocks or the potentially negative effects of afforestation is overly optimistic. The authors claim that these findings also indicate that the assumption of a fixed ratio between soil and biomass C, which has been widely used in previous studies for estimating soil C stocks is unreliable.

“According to this study pre-afforestation soil properties and original vegetation type need to be included in models of soil carbon dynamics; and extensive global-scale field investigations are required to improve the estimation of soil carbon stocks. Furthermore, the dependence of soil C changes on background soil C and tree species highlights the importance of site and species choices for maximizing afforestation C sequestration” said Prof. Josep Penuelas from CREAF-CSIC Barcelona.

Reference: Hong, S., Yin, G., Piao, S., Chen, A., Cong, N., Dybzinski, R., Peñuelas, J., Zeng, H. 2020. Divergent responses of soil organic carbon to afforestation. Nature Sustainability, doi: https://doi.org/10.1038/s41893-020-0557-y.

Un estudi de l’ICTA, el CREAF, el CTFC i la UAB caracteritza per primera vegada la química forestal de l’aire per sota la copa dels arbres en un alzinar mediterrani. Les concentracions màximes de monoterpens, els compostos orgànics volàtils relacionats amb la salut humana, es produeixen al juliol i agost, a primera hora del matí i de la tarda.

Montseny. Autor: Pixel (Wikimedia Commons)

La recerca Human Breathable Air in a Mediterranean Forest: Characterization of Monoterpene Concentrations under the Canopy realitzada per l’investigador Albert Bach, de l’Institut de Ciència i Tecnologia Ambientals de la Universitat Autònoma de Barcelona (ICTA-UAB), ha comprovat que els monoterpens que emeten les plantes dins d’un alzinar tenen nivells màxims durant el juliol i l’agost. Els monoterpens són les fragàncies que emeten les plantes per comunicar-se, fer fora depredadors o captar l’atenció dels pol·linitzadors, entre d’altres. Són compostos orgànics volàtils actualment en estudi per les seves propietats antiinflamatòries, neuroprotectores i antitumorogèniques. En la recerca hi han col·laborat els investigadors del CREAF Joan Llusià, Iolanda Filella i Josep Peñuelas, juntament amb altres del Centre de Ciència i Tecnologia Forestal de Catalunya (CTFC), del Consejo Superior de Investigaciones Científicas (CSIC) i del Departament de Geografia de la UAB.

L’estudi,  impulsat per la Fundació Bancària La Caixa i publicat a l’ International Journal of Environmental Research and Public Health, demostra que al bosc podem trobar aquests compostos a l’aire d’una forma molt variable. N’hi haurà més o menys depenent de l’estació de l‘any i l’hora del dia, sobretot segons la temperatura que faci, la radiació solar i la humitat. De fet, l’estudi ha comprovat que les màximes concentracions es produeixen durant el juliol i l’agost a primera hora del matí (de 6 a 8h) i de la tarda (de 13 a 15h), quan fa més calor i sol.

Els resultats suggereixen que, durant l’estiu, les persones que caminen per aquest tipus de boscos estarien subjectes a una major absorció potencial de monoterpens en el seu torrent sanguini, especialment a primera hora del matí i a partir del migdia. Les concentracions obtingudes són similars o majors que en d’altres estudis que han demostrat la relació entre aquests compostos i la salut de les persones, no només al laboratori sinó també al bosc.

Bosc i salut

Quan estem en contacte amb el bosc experimentem una sèrie d’efectes en la nostra salut en general: als sistemes cardiovascular, immunitari, respiratori i nerviós, als que s’hi afegeixen canvis en el benestar fisiològic i psicològic.

Tot i el seu paper rellevant al binomi bosc-salut, aquests compostos han estat poc estudiats per sota de la copa dels arbres, que és on té lloc la interacció amb les persones.  Per això, aquest estudi pioner obre un nou marc de recerca als boscos mediterranis i constitueix una aportació important per a la comunitat científica i de la sanitat pública.

Més informació: Bach, A.; Yáñez-Serrano, A.M.; Llusià, J.; Filella, I.; Maneja, R.; Penuelas, J. (2020). Human Breathable Air in a Mediterranean Forest: Characterization of Monoterpene Concentrations under the Canopy. International Journal of Environmental Research and Public Health. https://doi.org/10.3390/ijerph17124391

Font: Blog CREAF

Nutrient scarcity, and climate, are long existing evolutionary forces that have selected for multiple plant traits and have constrained the physiology of plants since their early development.

In a new study published in the journal Nature plants authors propose a mechanism by which nutrient scarcity may select for highly variable seed production, with weather patterns inducing masting synchrony across populations; they also discuss why wind-pollination and predator satiation cannot be the only selective pressures that select for highly variable reproduction.

Nutrient availability is a direct determinant of the mean fruit production in agriculture and in the wild. In this study, authors discuss why low nutrient availability may have been an important factor selecting for highly variable and synchronized seed production, the latter in combination with adaptation to variability in long-term climate patterns.

According to the authors, given the fact that temporally variable sexual reproduction in nature seems to be common, they conclude that factors others than wind pollination and predator satiation may have played a role in shaping this reproductive trait. “We suggest that one of these potential factors triggering a highly variable seed production, before wind pollination and predators evolved, may have been nutrient scarcity because of its role in determining the physiology of a broad range of organisms”, said Dr. Fernández-Martínez from University of Antwerp and collaborator of the Global Ecology Unit.

“This mechanism, which could have originated during the early evolution of plants, may explain why, under low nutrient availability, nutrient-conservative plants with highly variable reproduction may have been preferentially selected in comparison to nutrient-spending plants (with more constant reproduction).” said Prof. Josep Penuelas from CREAF-CSIC Barcelona.

Reference: Fernández-Martínez, M., Sardans, J., Sayol, F., LaMontagne, J.M., Bogdziewicz, M., Collalti, A., Hacket-Pain, A., Vacchiano, G., Espelta, J.M., Peñuelas, J., Janssens, I.A. 2020. Reply to: Nutrient scarcity cannot cause mast seeding. Nature Plants. DOI: 10.1038/s41477-020-0703-6.

According to a new study published in the journal Nature Ecology and Evolution the increase in gymnosperm sensitivity to drought suggests that their increasing intrinsic water use efficiency may not have alleviated the impacts of drought stress. Picture by Shutterstock

The frequency and intensity of droughts have grown over the decades, leading to increased forest decline. The response of forest to drought can be evaluated by its sensitivity to drought (resistance) and the post-drought recovery rate (resilience). However, it remains uncertain how drought resistance and resilience of forests have changed across the space and over time under climate change.

In a new study published in the journal Nature Ecology and Evolution authors assessed the spatio-temporal dynamics of forest resistance and resilience to drought over the past century (1901-2015) with global tree ring data records from 2935 sites and associated plant trait data. Authors point out that this study based on an analysis of long-term tree-ring data is the first one to report a trade-off in their recent trends between gymnosperm resistance and resilience to drought. According to the authors such decrease in drought resistance but increase in their drought resilience may potentially indicate a recent life-history strategy shift of gymnosperms in coping with changing climate and drought stress regimes.

“Surprisingly, we found that the trade-off between resistance and resilience for gymnosperms, previously reported only spatially, also occurred at the temporal scale. In particular, drought resilience significantly increased but resistance decreased for gymnosperms between 1950-1969 and 1990-2009, indicating that previous models simulations may have underestimated the impacts of drought on gymnosperm-dominated forests under future climate change”, said the PhD student  Xiangyi Li from the Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, China.

“We suggest that the altered ecosystem carbon cycle processes should be considered in the next generation of forest simulators to improve their predictive capacity of future ecosystem functioning and terrestrial carbon balance. The priority for further studies is to establish a network for long-term and synchronized observations of plant growth conditions and traits” said Prof. Josep Penuelas from CREAF-CSIC Barcelona.

Reference: Li, X., Piao, S., Wang, K., Wang, X., Wang, T., Ciais, P., Chen, A., Lian, X., Peng, S., Peñuelas, J. 2020. Temporal trade-off between gymnosperm resistance and resilience increases forest sensitivity to extreme drought. Nature Ecology and Evolution.

According to a new study published in the journal Trends in Ecology and Evolution, changes in the production of PSCs can lead to unforeseen consequences for soil structure and function and can disturb biological feedbacks on soil chemistry and biology, perhaps even on atmospheric chemistry and climate. Figure: © Trends in Ecology and Evolution, 2020.

Secondary compounds (PSCs ) in plants (formed from primary metabolites in specific pathways) are major contributors to the chemical diversity of nature.. The distribution of PSCs is heterogeneous across the plant kingdom, and these compounds exhibit extensive variation both among and within species. Knowledge of the effect of PSCs on belowground interactions in the more diffuse community of species living outside the rhizosphere is sparse compared with what we know about how PSCs affect aboveground interactions.

In a new study published in the journal Trends in Ecology and Evolution authors illustrate that PSCs from foliar tissue, root exudates, and leaf litter effectively influence such belowground plant–plant, plant–microorganism, and plant–soil invertebrate interactions.

The study shows that soil is a theater of facilitation, symbiosis, and warfare deployed by plants and the various organisms living in it, and PSCs have a major role mediating many of these interactions. Plants and soil organisms have adapted to withstand, detoxify, or use the cocktail of PSCs originally meant to harm some of them. ”Therefore, understanding PSC-mediated relationships at the community scale and identifying the compounds involved in these interactions is important for better insight into the functioning of these systems and their evolution, especially in changing environments” said Dr. Bodil K. Ehlers from Aarhus University, Denmark

According to the study climatic factors can induce PSC production and select for different plant chemical types. “Therefore, climate change can alter both quantitative and qualitative PSC production, and how these compounds move in the soil. This can change the soil chemical environment, with cascading effects on both the ecology and evolution of belowground species interactions and, ultimately, soil functioning” said Prof. Josep Penuelas from CREAF-CSIC Barcelona.

“We encourage the creation of open, community-wide, curated, labeled, broad-spectrum PSC data sets across plant species and soils, because this would greatly increase the transfer of knowledge between scientists studying plants, microbes, and invertebrates in this biological belowground theatre” added Prof. Josep Penuelas from CREAF-CSIC Barcelona.

.Reference: Ehlers, B.K., Berg, M.P., Staudt, M., Holmstrup, M., Glasius, M., Ellers, J., Tomiolo, S., Madsen, R.B., Slotsbo, S., Penuelas, J. 2020. Plant Secondary Compounds in Soil and Their Role in Belowground Species Interactions. Trends in Ecology & Evolution, doi: 10.1016/j.tree.2020.04.001.

Plants and vegetation play a critical role in supporting life on Earth, but there is still a lot of uncertainty in our understanding of how exactly they affect the global carbon cycle and ecosystem services. A new IIASA-led study explored the most important organizing principles that control vegetation behavior and how they can be used to improve vegetation models.

We rely on the plants that make up our planet’s ecosystems to release oxygen into the atmosphere, absorb carbon dioxide (CO₂), and provide habitat and food for wildlife and humans. These services are critical in the future management of climate change, especially in terms of CO₂ uptake and release, but due to the many complex, interacting processes that affect the ability of vegetation to provide these services, they remain difficult to predict.

In an IIASA-led perspective published in the journal Nature Plants, an international team of researchers endeavored to address this problem by exploring approaches to master this complexity and improve our ability to predict vegetation dynamics. They explored key organizing principles that govern these processes – specifically, natural selection; self-organization (controlling collective behavior among individuals); and entropy maximization (controlling the outcome of a large number of random processes). In general, an organizing principle determines or constrains how components of a system, such as different plants in an ecosystem or different organs of a plant, behave together. Mathematically, such a principle can be seen as an additional equation added to a system of equations, allowing one or more previously unknown variables in the system to be determined and thereby reducing the uncertainty of the solution.  

A lot of research has gone into understanding and predicting how plant processes combine to determine the dynamics of vegetation on larger scales. To integrate process understanding from different disciplines, dynamic vegetation models (DVMs) have been developed that combine elements from plant biogeography, biogeochemistry, plant physiology, and forest ecology. DVMs have been widely used in many fields including the assessment of impacts of environmental change on plants and ecosystems; land management; and feedbacks from vegetation changes to regional and global climates. However, previous attempts to improve vegetation models have mainly focused on improving realism by including more processes and more data. This has not led to the expected success because each additional process comes with uncertain parameters, which has in turn caused an accumulation of uncertainty and therefore unreliable model predictions.

“Despite the ever-increasing availability of data, and the fact that vegetation science, like many other scientific fields, is benefitting from increasing access to big data sets and new observation technologies, we also need to understand governing principles like evolution to make sense of the big data. Current models are not able to reliably predict long-term vegetation responses,” explains lead author Oskar Franklin, a researcher in the IIASA Ecosystems Services and Management Program.  

“The study found that by representing the principles of evolution, self-organization, and entropy maximization in models, they could better predict complex plant behavior and resulting vegetation as an emerging result of environmental conditions” explains one of the members of the international team of researchers, Josep Penuelas from CREAF-CSIC Barcelona. [JP1] Although each of these principles had previously been used to explain a particular aspect of vegetation dynamics, their combined implications were not fully understood. This approach means that a lot of complex variation and behavior at different scales, from leaves to landscapes, can now be better predicted without additional understanding of underlying details or more measurements.

The authors expect that apart from leading to better tools for understanding and managing the biosphere, the proposed “next-generation approach” may result in different trajectories of projected climate change that both policy and the general public would have to cope with.

Reference

Franklin O, Harrison S, Dewar R, Farrior C, Brännström A, Dieckmann U, Pietsch S, Falster D, ….Penuelas J,….et al. (2020). Organizing principles for vegetation dynamics. Nature Plants DOI: 10.1038/s41477-020-0655-x

Contacts:

Researcher contact

Oskar Franklin

Research scholar

Ecosystems Services and Management Program

Tel: +43 2236 807 251

franklin@iiasa.ac.at

Resource: Press Officer

Ansa Heyl

IIASA Press Office

Tel: +43 2236 807 574

Mob: +43 676 83 807 574

heyl@iiasa.ac.at

About IIASA:

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 [JP1]Això ho he tocat jo per adaptar-ho al nostre ambit d’actuació…jo no hi era a la nota original, com es lògic.