Prof. Josep Peñuelas Reixach, has received the ‘Alejandro Malaspina’ National Research Award, in the area of ​​Material Resources Sciences and Technologies. He receives the award for his extensive scientific career as an international reference in global change research, as well as his leadership in technological innovation and outreach work in this area.

The National Research Awards recognize the merit of those researchers of Spanish nationality who are carrying out outstanding work in scientific fields of international relevance and who contribute significantly to the advancement of scientific knowledge and the progress of Humanity. There are 10 modalities that correspond to 10 areas of knowledge.

The National Research Awards 2023 are Spain’s most important recognition in the field of scientific research.

Prof Peñuelas has stated to be “very happy to receive this prize, which is the product of the research of our entire group of research”

Variation in plant traits arises from balancing the costs and benefits of resource-use strategies at the leaf level. The interplay between natural selection and environmental filtering leads to predictable patterns in traits that promote the efficiency of plant processes necessary for growth, survival, and reproduction.

In a recent publication in the journal Nature Communications, researchers explore whether trade-offs and optimality principles in leaf functional traits extend to the ecosystem level. By analyzing a comprehensive dataset from 98 global eddy covariance flux measurement sites and utilizing vegetation data collected in the field and from global plant trait databases, the authors investigate ecosystem-scale analogs to the relationships observed in functional traits.

The leaf economics spectrum, which represents consistent correlations among various leaf traits reflecting a range of plant strategies from conservative to acquisitive, is examined. Additionally, the study explores the global spectrum of plant form and function, which encompasses evolutionary strategies related to plant growth, survival, and reproduction. The researchers also investigate the least-cost hypothesis, which suggests that plants acclimate to minimize carbon costs associated with photosynthesis on a per-leaf-area basis.

The findings of this study indicate that coordination of functional properties is conserved at the ecosystem scale. However, it is important to note that additional processes occur at the ecosystem level compared to the leaf level, emphasizing the significance of scale-emergent properties in understanding and predicting ecosystem behavior. Ulisse Gomarasca from the Max Planck Institute for Biogeochemistry highlights the importance of evaluating ecosystem functional properties for the development of more realistic global dynamic vegetation models, which can reduce uncertainty in climate change projections.

The study provides strong evidence supporting the conservation of the leaf economics spectrum at the ecosystem level. Similarly, the global spectrum of plant form and function and the least-cost hypothesis are observed in whole ecosystems, despite involving secondary mechanisms at the ecosystem scale.

Prof. Josep Penuelas from CSIC-CREAF emphasizes the need for upscaling from leaf or plant to ecosystem-level processes in order to make more accurate predictions about ecosystem responses to global environmental changes. This involves considering whether the coordination observed at the leaf and plant levels is conserved at the ecosystem scale or whether scale-emergent behaviors occur and should be explicitly incorporated into models.

Publication: Gomarasca, U., Migliavacca, M., Kattge, J., Nelson., Niinemets, Ü., Wirth, C., Cescatti, A., Bahn., Nair, R., Acosta, A., Arain, A., Beloiu, M., Black, T., Bruun, H.H., Bucher, F., Buchmann, N., Carrara, A., Byun, C., Conte, A., da Silva, A., Duveiller, G., Fares, S., Ibrom, A., Knohl, A., Komac, B., Limousin, J-M., Lusk, C., Mahecha, M., Martini, D., Minden, V., Montagnani, L., Mori, A., Onoda, Y., Penuelas, J., Poschlod, P., Powell, T., Reich, P., Šigut, L., van Bodegom, P., Walther, S., Wohlfahrt, G., Wright, I., Reichstein, M. 2023. Leaf-level coordination principles propagate to the ecosystem scale. Nature Communications 14:3948. Doi: 10.1038/s41467-023-39572-5.

Current anthropogenic warming, as a result of greenhouse had emission, particularly carbon dioxide (CO₂), poses a very high risk to nature and human well-being. Up to now, this risk has been buffered by a key group of other species on the planet, terrestrial plants, which have assimilated almost a third of emissions, helping us avoid a much stronger and faster degree of warming.

In a new paper published in One Earth journal, author raises the question of how long will plants continue to rescue us. According to Prof Josep Penuelas from CSIC-CREAF, several signals suggest that this carbon-sink activity might be decreasing its efficiency and slowing its rate of increase because of limitations of nutrients, water, heat, fires, pollution, and reduced vegetation carbon residence time.

Author highlights that plant production requires many more nutrients than just C and N. Bio-elements such as phosphorus (P), potassium, calcium, magnesium, molybdenum, manganese, and zinc are needed for information and energy production and storage, functional control, catalytic power, physiological processes, and cell homeostasis, i.e., for cell structure and function, and therefore for plant growth. The availability of carbon from rising atmospheric carbon dioxide levels, and of nitrogen from various human-induced inputs to ecosystems, is continuously increasing. However, these increases are not paralleled by a similar increase in all these other bio-elements.

According to the study the limitations for increasing carbon sinks do not end with nutrients; many other limitations are linked to climate change itself, which raises temperatures above the optimum and drives aridification of many regions. With all these conspiring factors, we can thus expect the pace of current carbon sinks to slow because of decreased efficiency.

This scenario calls for a reconsideration of IPCC climate projections toward a possible reduction in the mitigation capacity of the terrestrial biosphere even warmer conditions than currently projected and stronger impacts. “If current models continue to ignore it, they may overestimate carbon sinks, and therefore underestimate climate warming and overestimate mitigation potential”, noted Prof. Penuelas.

Climate change is unfortunately already here and may become stronger if mitigation actions do not fully succeed, so countries should also aim to develop better adaptation strategies. Currently, adaptation strategies are largely fragmented, local, and incremental, with limited evidence of transformational adaptation and negligible evidence of risk reduction outcomes. “As we shift from a fertilization-dominated to a warming-dominated biosphere, we need to diversify our approaches and take action to healing harms already inflicted and avoid worse future ones”, concludes Prof. Penuelas.

Penuelas, J. 2023. Decreasing efficiency and slowdown of the increase in terrestrial carbon-sink activity. One Earth, Vol. 6, Issue 6p591–594 Published in issue: June 16, 2023

A study published this week in the renowned journal Nature shows clear signs of destabilizing carbon uptake by land ecosystems in large regions of the world. In particular, the difference between the CO₂ taken up and the CO2 released into the atmosphere in these regions increasingly differs across years, with high plant productivity (and high carbon sequestration) in some years and low plant productivity (and low sequestration) in others. The study’s authors warn that such increasing variability indicates a risk of ecosystems becoming destabilized, spiralling away from their current situation and undergoing abrupt changes.

“We have not only detected an increase in variability in these areas, but also an increase in their ‘memory’ — temporal autocorrelation — which indicates that carbon uptake in one year is increasingly positively related to the previous year. A lower carbon uptake in one year is therefore becoming more likely to be followed by an even lower uptake the next year, ” says the study’s lead author, Marcos Fernández, researcher at CREAF and University of Antwerp “These are clear symptoms of a possible destabilization of the major ecosystems affected, something that might entail an abrupt change in the way they work and, in their landscapes,” he continues. “In Mediterranean ecosystems, for example, forests could become scrublands that are unable to turn back into forests in the current climate.”

The study confirms that that the areas most at risk of destabilization have less forest cover and more cropland, are warmer, and have experienced greater rises in temperature variability, which could be related to an increase in extreme weather events, such as heatwaves and cold snaps. These areas include the Mediterranean region, eastern Africa, the west coasts of North and Central America, India and Pakistan, and Southeast Asia.

To carry out the study, the research team worked with global net ecosystem production data for the 1981-2018 period from CAMS and CarboScope, two global atmospheric inversion models. They also used net ecosystem production data from TRENDY, an ensemble of 12 dynamic global vegetation models.

Instability constrains carbon sequestration

The study shows that carbon sequestration capacity has been compromised in the regions with the greatest potential for destabilization in recent years , whereas it has increased in areas where variability has declined, such as the Amazon and parts of central and northern Europe. “In the case of the Amazon, despite carbon having been lost on average over the study period, the losses are smaller and smaller because these systems have actually been increasing their carbon sequestration capacity,” explains CREAF-based CSIC research professor Josep Peñuelas.

“Being able to predict the carbon cycle is vital to combating climate change If their carbon uptake capacity declines, society will need to reduce their carbon emissions faster than is currently assumed” remarks CREAF researcher Jordi Sardans, another of the study’s authors. “While we do not yet know whether such abrupt changes will alter the climate or plants’ carbon sequestration capacity, a possible destabilization of large regions of the biosphere complicates making predictions because it greatly increases variability.”

Does greater biodiversity mean more stability?

The study found variability in carbon sequestration to be at its greatest in regions with intermediate biodivesity too.

In ecology, it is always said that the most biodiverse ecosystems, those with the greatest wealth and diversity of species, are the most stable and productive, giving them the highest carbon sequestration capacity. The study put that notion to the test in all the regions under analysis. The researchers found carbon sequestration rates to be highest in regions with intermediate biodiversity values, and lower in places with a very high level of biodiversity, such as the tropics.. According to the authors, this could be due to the positive effect that biodiversity has on decomposition and respiration, offsetting the positive effect of photosynthesis in tropical ecosystems, something that would not happen in other ecosystems. Additionally, and in contrast to what was previously thought, the study found variability in carbon sequestration to be at its greatest in regions with intermediate biodiversity too. Given the global scale of the study, it is very difficult to pinpoint the mechanisms that have given rise to its findings.

Led by CREAFand Antwerp University, the study was carried out by a team including scientists from the Spanish National Research Council CSIC, the University of Barcelona, the University of Paris-Saclay , (France), theInternational Institute for Applied Systems Analysis(Austria), University of Oxford(UK), the Max Planck Institute for Biogeochemistry, (Germany), the University of Exeter (UK), the Canadian Centre for Climate Modelling and Analysis (Canada), the University of Illinois (USA), the National Center for Atmospheric Research (USA), and the National Centre for Atmospheric Science (UK).

Article:

Fernández- Martínez M. Peñuelas J. Chevallier F, Ciais P, Obersteiner M, Rödenbeck C, Sardans J, Vicca S, Yang H, Sitch S, Friedlingstein P, Arora K, Goll D, K.Jain A,.Lombardozzi D, McGuire P, A.Janssens I, Diagnosing destabilization risk in global land carbon sinks. Nature DOI : 10.1038/s41586-023-05725-1 2021-11-17874

Source: https://blog.creaf.cat/en/noticias/carbon-sequestration-risk-destabilization-large-regions-world/

Un estudio publicado esta semana en la prestigiosa revista Nature ha detectado signos claros de que el secuestro de carbono está en riesgo de desestabilizarse en grandes regiones del planeta. El estudio demuestra que, en algunas zonas, el secuestro de carbono (la diferencia entre el CO₂ que capturan y liberan los ecosistemas a la atmósfera) ha variado mucho en los últimos años, con años con mucha productividad vegetal (mucho secuestro) y años con poca (poco secuestro). Los autores alertan de que esta variabilidad es una señal de que los ecosistemas podrían estar en riesgo de desestabilizarse y entrar en una espiral que les alejase de la situación actual y los llevara a cambios abruptos.

«Por ejemplo, en los ecosistemas mediterráneos, podríamos ver bosques que pasan a ser matorrales sin capacidad de volver a la forma original de bosque», comenta Marcos Fernández, primer autor del estudio, investigador del CREAF y colaborador de la Universidad de Barcelona que estaba en la Universidad de Antwerp en el momento de la investigación, y añade, “en estas zonas también hemos detectado otra señal, un aumento en su “memoria” (autocorrelación temporal), indicando que cada valor está cada vez más positivamente relacionado con lo anterior de modo que si un valor es decreciente, el siguiente será aún más decreciente”.

El estudio confirma que las zonas que más riesgo presentan de desestabilizarse tienen menos bosques, más cultivos, son más cálidas y han sufrido mayores aumentos en la variabilidad de sus temperaturas, lo que podría estar relacionado con un aumento de los episodios de tiempo extremo como oleadas de calor y de frío. En el mapa, estas regiones serían la zona mediterránea, la zona este de África oriental, las costas occidentales de Norte América y Centro Americano, India y Pakistán o el sureste asiático.

Para realizar el estudio el equipo de investigación ha trabajado con los datos globales de producción neta de los ecosistemas para el período 1981-2018 de dos modelos globales de inversión atmosférica (CAMS y CarboScope). También datos de producción limpia de los ecosistemas de un conjunto de 12 modelos dinámicos de vegetación global (TRENDY).

La naturaleza inestable limita el secuestro de carbono

El estudio pone de manifiesto que las regiones con un potencial más elevado de desestabilizarse en los últimos años han visto comprometida su capacidad de secuestrar carbono. Por el contrario, las zonas que han tendido a ser menos variables (Amazonas o regiones del centro y norte de Europa, entre otras) han aumentado su capacidad de secuestrar carbono. «En el caso del Amazonas vemos concretamente que aunque durante el período de estudio, de media, ha perdido carbono, cada vez pierde menos porque el sistema es ahora menos variable que antes», complementa Josep Peñuelas, profesor de investigación del CSIC en el CREAF.

“Poder predecir el ciclo del carbono es clave en la lucha contra el cambio climático. Aunque todavía no sabemos si estos cambios abruptos traerán cambios en el clima o en la capacidad de las plantas de secuestrar carbono, una potencial desestabilización de grandes regiones de la biosfera nos hace las predicciones más difíciles porque aumenta mucho la variabilidad”, comenta Jordi Sardans, también autor e investigador del CREAF.

¿Los sistemas que tienen más biodiversidad, son más estables?

La máxima variabilidad en el secuestro de carbono también se da en regiones con biodiversidad intermedia.

En ecología siempre se dice que los ecosistemas más biodiversos, con mayor diversidad y riqueza de especies, son más estables y productivos, y por tanto tienen más capacidad de secuestrar carbono. En este estudio se ha querido testear esto en todas las regiones del mundo estudiadas y se ha visto que las tasas más elevadas de secuestro de carbono se dan en regiones con biodiversidad intermedia, mientras que en lugares donde la biodiversidad es muy elevada, como ahora los trópicos, esta capacidad de secuestro de carbono es menor.. Según apuntan los investigadores, esto puede deberse a que el efecto positivo de la biodiversidad sobre la descomposición y respiración de los ecosistemas tropicales podría compensar el efecto positivo sobre la fotosíntesis, lo que no ocurriría en otros ecosistemas. Por otra parte, y en contra de lo que se pensaba, este trabajo también apunta a que la máxima variabilidad en el secuestro de carbono también se da en regiones con biodiversidad intermedia. Dada la escala global de este estudio, entender los mecanismos detrás de estos resultados resulta muy difícil.

El artículo ha estado liderado por el CREAF y la Universitat de Antwerp, Bélgica, ha contado con la colaboración de un equipo con miembros del Consejo Superior de Investigaciones Científicas CSIC, de la Universitat de Barcelona, la Universidad Paris-Saclay, Francia, delInternational Institute for Applied Systems Analysis, Austria, la Universidad de Oxford, Reino Unido, del Max Planck Institute for Biogeochemistry, Alemania, de la Universidad de Exeter, Reino Unido, del Canadian Centre for Climate Modelling and Analysis , Canada, de la Universidad de Illinois, EEUU, del National Center for Atmospheric Research, EEUU y del National Centre for Atmospheric Science, Reino Unido.

Artículo:

Fernández- Martínez M. Peñuelas J. Chevallier F, Ciais P, Obersteiner M, Rödenbeck C, Sardans J, Vicca S, Yang H, Sitch S, Friedlingstein P, Arora K, Goll D, K.Jain A,.Lombardozzi D, McGuire P, A.Janssens I, Diagnosing destabilization risk in global land carbon sinks. Nature DOI : 10.1038/s41586-023-05725-1 2021-11-17874

Fuente: https://blog.creaf.cat/es/noticias/secuestro-carbono-riesgo-desestabilizarse-grandes-regiones-planeta/

Un estudi publicat aquesta setmana a la prestigiosa revista Nature ha detectat signes clars de que el segrest de carboni està en risc de desestabilitzar-se en grans regions del planeta. L’estudi demostra que, en algunes zones, el segrest de carboni (la diferencia entre el CO₂ que capturen i alliberen els ecosistemes a l’atmosfera) ha variat molt els darrers anys, amb anys amb molta productivitat vegetal (molt segrest) i anys amb poca (poc segrest). Els autors alerten que aquesta variabilitat és una senyal que els ecosistemes podrien estar en risc de desestabilitzar-se i entrar en una espiral que els allunyés de la situació actual i els portés a canvis abruptes.

“Per exemple, als ecosistemes mediterranis, hi podríem veure boscos que passen a ser matollars sense capacitat de retornar a la forma original de bosc”, comenta Marcos Fernández, primer autor de l’estudi, investigador del CREAF i col·laborador de la Universitat de Barcelona que estava a la Universitat d’Antwerp en el moment de la recerca , i afegeix, “en aquestes zones també hem detectat una altra senyal, un augment en la seva “memòria” (autocorrelació temporal), indicant que cada valor està cada cop més positivament relacionat amb l’anterior de manera que si un valor és decreixent, el següent encara serà més decreixent”.

L’estudi confirma que les zones que més risc presenten de desestabilitzar-se tenen menys boscos, més conreus, són més càlides i han patit augments més grans en la variabilitat de les seves temperatures, el que podria estar relacionat amb un augment dels episodis de temps extrem com ara onades de calor i de fred. En el mapa, aquestes regions serien la zona mediterrània, la zona est d’Àfrica oriental, les costes occidentals de Nord Amèrica y Centre Americà, Índia i Pakistan o el sud est asiàtic.

Per fer l’estudi l’equip de recerca ha treballat amb les dades globals de producció neta dels ecosistemes per al període 1981-2018 de dos models globals d’inversió atmosfèrica (CAMS i CarboScope). També dades de producció neta dels ecosistemes d’un conjunt de 12 models dinàmics de vegetació global (TRENDY).

La natura inestable limita el segrest de carboni

L’estudi fa palès que les regions amb un potencial més elevat de desestabilitzar-se els darrers anys han vist compromesa la seva capacitat de segrestar carboni. Al contrari, les zones que han tendit a ser menys variables (Amazones o regions del centre i nord d’Europa, entre d’altres) han augmentat la seva  capacitat de segrestar carboni. “En el cas de l’Amazones veiem concretament que tot i que durant el període d’estudi, de mitjana, ha perdut carboni, cada cop en perd menys perquè el sistema és ara menys variable que abans”, complementa Josep Peñuelas, professor d’investigació del CSIC al CREAF.

“Poder predir el cicle del carboni és clau en la lluita contra el canvi climàtic. Tot i que encara no sabem si aquests canvis abruptes portaran canvis en el clima o en la capacitat de les plantes de segrestar carboni, una potencial desestabilització de grans regions de la biosfera ens fa les prediccions més difícils perquè augmenta molt la variabilitat”, comenta Jordi Sardans, també autor i investigador del CREAF.

Els sistemes que tenen més biodiversitat són més estables?

La màxima variabilitat en el segrest de carboni també es dona en regions amb biodiversitat intermèdia.

En ecologia sempre es diu que els ecosistemes més biodiversos, amb més diversitat i riquesa d’espècies, són més estables i productius, i per tant tenen més capacitat de segrestar carboni. En aquest estudi s’ha volgut testejar això en totes les regions del món estudiades i s’ha vist que les taxes més elevades de segrest de carboni es donen a regions amb biodiversitat intermèdia, mentre que a llocs on la biodiversitat és molt elevada, com ara els tròpics, aquesta capacitat de segrest de carboni és més baixa. Segons apunten els investigadors, això pot ser degut a que l’efecte positiu de la biodiversitat sobre la descomposició i respiració dels ecosistemes tropicals podria compensar l’efecte positiu sobre la fotosíntesi, cosa que no passaria en altres ecosistemes. D’altra banda, i en contra del que es pensava, aquest treball també apunta a que la màxima variabilitat en el segrest de carboni també es dona en regions amb biodiversitat intermèdia. Donada l’escala global d’aquest estudi, escatir els mecanismes darrera d’aquests resultats resulta molt difícil.

L’article ha estat liderat pel CREAF i la Universitat d’Antwerp, Bèlgica, ha comptat amb la col·laboració d’un equip amb membres del Consejo Superior de Investigaciones Científicas CSIC, de la Universitat de Barcelona, la Universitat Paris-Saclay, França, de l’International Institute for Applied Systems Analysis, Àustria, la Universitat d’Oxford, Regne Unit, del Max Planck Institute for Biogeochemistry, Alemanya, de la Universitat d’Exeter, Regne Unit, del Canadian Centre for Climate Modelling and Analysis, Canada, de la Universitat d’Illinois, EEUU, del National Center for Atmospheric Research, EEUU i del National Centre for Atmospheric Science, Regne Unit.

Article:

Fernández- Martínez M. Peñuelas J. Chevallier F, Ciais P, Obersteiner M, Rödenbeck C, Sardans J, Vicca S, Yang H, Sitch S, Friedlingstein P, Arora K, Goll D, K.Jain A,.Lombardozzi D, McGuire P, A.Janssens I, Diagnosing destabilization risk in global land carbon sinks. Nature DOI : 10.1038/s41586-023-05725-1 2021-11-17874

Font: https://blog.creaf.cat/noticies/segrest-carboni-risc-desestabilitzar-se-grans-regions-del-planeta/

Hypoxia, defined as dissolved oxygen (DO) in water < 2 mg L-1, has occurred worldwide in estuarine and coastal environments during the past five decades. Estuarine and coastal hypoxia not only alters regional biogeochemical processes and also affects biodiversity and fisheries. It is well known that climate warming and eutrophication are increasingly important to hypoxia occurrence in terrestrial aquatic environments, the mechanisms underlying estuarine and coastal hypoxia, however, are still poorly constrained, mostly due to the limited long-term observation and interpretation.

In a new study published in the journal JGR Biogeosciences, authors compared DO concentrations and the driving factors of hypoxia between northwestern and southern Hong Kong and Mirs Bay.

According to the study, deoxygenation was weak in the bottom layer in northwestern Hong Kong, although the DO was consistently undersaturated, whereas a rapid decrease in the annual minimum DO was observed in the bottom layer in southern Hong Kong and Mirs Bay. “The seasonal DO depletion and/or hypoxia in the bottom water was accompanied by supersaturated DO and high Chl-a in surface water in southern Hong Kong, indicating local excessive productivity and triggering oxygen depletion” comments Dr. Wwi Qian from the Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education, Fujian Normal University, China.

The predeoxygenation of bottom water and long water residence time have contributed to the deoxygenation in Mirs Bay. Water stratification could exacerbate hypoxia by preventing oxygen replenishment from the surface to the bottom layers. The upwelling water from the South China Sea and/or Kuroshio contributed inappreciably to the significant deoxygenation in southern Hong Kong and Mirs Bay.

“These results suggest that enhanced productivity and oxygen consumption, combined with stratification and currents, are increasingly driving hypoxia in the Pearl River Estuary and adjacent areas” concludes Prof. Josep Penuelas from CREAF-CSIC Barcelona

Reference: Qian, W., Zhang, S., Tong, C., Sardans, J., Peñuelas, J., Li, X. 2022. Long-term Patterns of Dissolved Oxygen Dynamics in the Pearl River Estuary. JGR Biogeosciences 127(7), e2022JG006967, doi: 10.1029/2022JG006967.

Climatic warming has lengthened the photosynthetically active season in recent decades, thus affecting the functioning and biogeochemistry of ecosystems, the global carbon cycle, and climate. The temperature response of carbon uptake phenology varies spatially and temporally, even within species, and the daily total intensity of radiation may play a role.

In a new study, published in the journal Global Change Biology, authors empirically modelled the thresholds of temperature and radiation under which daily carbon uptake is constrained in the temperate and cold regions of the Northern Hemisphere, which include temperate forests, boreal forests, alpine, and tundra biomes.

According to the study, radiation will constrain the trend towards longer growing seasons with future warming, but differently during the start and end of season and depending on the biome type and region. The study revealed that radiation is a major factor limiting photosynthetic activity that constrains the phenology response to temperature during the end-of-season. The beginning of carbon uptake, on the other hand, is highly sensitive to temperature but not constrained by radiation at the hemispheric scale. Dr. Adrià Descals from CREAF-CSIC says “Our results show that the photosynthetically active season in evergreen needleleaved forests begins shortly after conditions for growth become favorable and ends when these conditions get worse.” He also says, “It is important to take into account radiation, temperature, and their covariance when modeling the photosynthetically active season in evergreen needleleaved forests and their responses to climatic warming.” 

The study shows that the senescence stage has a low temperature dependency due to the constraints of radiation, and this might be a reason for the lower magnitude in the end-of-season delay than the start-of-season advance.

“This study thus revealed that while at the end-of-season the phenology response to warming is constrained at the hemispheric scale, at the start-of-season the advance of spring onset may continue, even if it is at a slower pace”, concludes Prof. Josep Penuelas from CREAF-CSIC Barcelona

Reference: Descals, A., Verger, A., Yin, G., Filella, I., Fu, Y.H., Piao, S., Janssens, I.A., Peñuelas, J. 2022. Radiation‐constrained boundaries cause nonuniform responses of the carbon uptake phenology to climatic warming in the Northern Hemisphere. Global Change Biology, doi: 10.1111/gcb.16502, in press.

As air temperature rises, the phenological cycle of Northern Hemisphere (NH) ecosystems is shifting progressively towards earlier leaf emergence and delayed leaf senescence, which leads to rapid lengthening of the active growing season.

Vegetation biophysics have long been recognized as a key regulator of seasonal air temperature climatology. For example, in early spring, the rate of air temperature increase rapidly decreases after leaf unfolding (typically for deciduous forests) due to increased transpiration after leaf-out that can effectively cool the leaf surface.

In a new study published in the journal Nature Communications, authors go into the critical role of plants in local temperature seasonality suggesting that greening will alter the seasonality of NH warming at annual to decadal timescales.

According to the study, vegetation greening also affects climate by interacting with other land-surface (e.g., snow or soil moisture) and atmospheric (e.g., water vapor, cloud, and circulation) processes the effects of which vary both geographically and seasonally. Thus, seasonal greening of Northern Hemisphere (NH) ecosystems, due to extended growing periods and enhanced photosynthetic activity, could modify near-surface warming by perturbing land-atmosphere energy exchanges, yet this biophysical control on warming seasonality is underexplored.

“We show that summer greening effectively dampens NH warming by −0.15 ± 0.03 °C for 1982–2014 due to enhanced evapotranspiration. However, greening generates weak temperature changes in spring (+0.02 ± 0.06 °C) and autumn (−0.05 ± 0.05 °C), because the evaporative cooling is counterbalanced by radiative warming from albedo and water vapor feedbacks. Moreover, greening-triggered energy imbalance is propagated forward by atmospheric circulation to subsequent seasons and causes sizable time-lagged climate effects. Overall, greening makes winter warmer and summer cooler, attenuating the seasonal amplitude of NH temperature” explains Dr. Xu Lian from the Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China.

Thus, the study highlights the need to better understand these biophysical processes operating both within and across seasons so that their potential time-lagged climate benefits and/or counterproductive consequences will not be overlooked.

“These findings demonstrate complex tradeoffs and linkages of vegetation-climate feedbacks among seasons and highlights the need to better understand these biophysical processes operating both within and across seasons so that their potential time-lagged climate benefits and/or counterproductive consequences will not be overlooked”, concludes Prof. Josep Penuelas from CREAF-CSIC Barcelona, who adds: “The regulatory role of greening on seasonal climate also has implications for adaptation planning and decision-making, as greening is now increasingly shaped by human land-use practices such as afforestation and reforestation”.

Reference: Lian, X., Jeong, S., Park, C-E., Xu, H., Li, L.Z.X., Wang, T., Gentine, P., Peñuelas, J., Piao, S. 2022. Biophysical impacts of northern vegetation changes on seasonal warming patterns. Nature Communications (2022) 13:3925.  Doi: 10.1038/s41467-022-31671-z.

Trees play a vital role in the biosphere. As key agents in the flow of energy and matter, they protect catchments and stabilize drainage areas, sequester carbon, and regulate climate on local to global scale. Trees also provide habitat for a large proportion of the diversity of the world’s vertebrates, invertebrates, and fungi. The magnitude of many of these functions and services increases as tree diversity increases, and greater functional diversity of tree assemblages enhances ecosystem productivity and stability. However, continued global forest loss and degradation has decimated biodiversity among tree and tree-dependent organisms.

In a new study published in the journal Proceedings of the National Academy of Sciences, authors analyze a recently developed global database of 46,752 tree species’ ranges to:

1. assess range protection and anthropogenic pressures for tree species
2. identify priority areas for conservation of tree diversity considering multiple diversity dimensions
3. assess the geographic distribution of current protected areas and different potential conservation prioritization scenarios and their respective coverage of global tree species diversity.

According to this research study, globally, 83.8% of the 46,752 tree species evaluated in this analysis are subject to moderate to very high human pressure, with protected areas (PA) grid cells covering only ≤25% of the ranges for 23.5% of tree species. Further, a total of 6,377 small-range tree species remain completely unprotected, according to the study. At the same time, a total of 14.8% tree species experience high to very high human pressure even within existing PAs.

Further analysis carried out by the authors found existing PA grid cells are estimated to cover only about half of the critical areas for tree diversity, as quantified by taxonomic, phylogenetic and functional diversity dimensions. These results highlight the pressing need for stronger protection of Earth’s tree diversity. “Our results also show that expanding PAs according to the top 17% and especially the 50% priority areas, would yield strong improvements in PA coverage of trees, as would implementing some of the major proposals for increased general biodiversity protection, notably the Global 200 Ecoregions framework”, explains Dr. Guo from the Aarhus University (Denmark) and the East China Normal University (China).

The priority areas identified for trees match well to the Global 200 Ecoregions framework, revealing that priority areas for trees would in large part also optimize protection for terrestrial biodiversity overall.

“Based on range estimates for an unprecedented number of tree species, our findings show that a large proportion of tree species receive limited protection by current PAs and are under substantial human pressure. Improved protection of biodiversity overall would robustly benefit global tree diversity”, concludes Prof. Josep Penuelas from CREAF-CSIC Barcelona.

Reference: Guo, W-Y., Serra-Diaz, J.M., Schrodt, F., Eiserhardt, W.L., Maitner, B.S., Merow, C., Violle, C., Anand, M., Belluau, M., Bruun, H.H., Byun, C., Catford, J.A., Cerabolini, B.E.L., Chacón-Madrigal, E., Ciccarelli, D., Cornelissen, J.H.C., Dang-Le, A.T., de Frutos, A., Dias, A.S., Giroldo, A.B., Guo, K., Gutiérrez, A.G., Hattingh, W., He, T., Hietz, P., Hough-Snee, N., Jansen, S., Kattge, J., Klein, T., Komac, B., Kraft, N., Kramer, K., Lavorel, S., Lusk, C.H., Martin, A.R., Mencuccini, M., Michaletz, S.T., Minden, V., Mori, A.S., Niinemets, U., Onoda, Y., Peñuelas, J., Pillar, V.D., Pisek, J., Robroek, B.J.M., Schamp, B., Slot, M., Egon Sosinski Jr., E., Soudzilovskaia, N.A., Thiffault, N., van Bodegom, P., van der Plas, F., Wright, J.J., Bing Xu, W., Zheng, J., Enquist, B.J., Svenning, J.C.. 2022. High exposure of global tree diversity to human pressure. Proceedings of the National Academy of Sciences 119 (25), e2026733119. Doi: 10.1073/pnas.2026733119 1.