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”
Optimality principles and patterns in trait coordination have been widely studied and confirmed at the leaf and plant scale. The question now is whether these coordination principles that apply to the leaf and plant scales can be used to approximate ecosystem-scale coordination among communities and ecosystems. Image: Pixabay/ FreePhotosART
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.
Anthropogenic fertilization of the Earth with increasing concentrations of atmospheric CO2 and nitrogen in-puts has enhanced plant photosynthesis and carbon sinks of terrestrial ecosystems. Several signals now suggest, however, that this carbon-sink activity is slowing its rate of increase because of limitations of nutrients, water, and heat, among other factors. Image: Pixabay.
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.
Mediterranean scrubland. Source: Joaquim F. P. a Flickr.
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 atmospherein 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 professorJosep 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.”
Tropical forest at Brasil. Source: Toni Arnau (RUIDO photo).
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.
Matorral mediterráneo Fuente: Joaquim F. P. a Flickr.
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.
Bosque tropical en Brasil. Fuente: Toni Arnau (RUIDO photo).
¿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.
Matollars mediterrànis. Font: Joaquim F. P. a Flickr.
Un estudi publicat aquesta setmana a la prestigiosa revista Natureha 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”, complementaJosep 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.
Bosc tropical al Brasil. Font: Toni Arnau (RUIDO photo).
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.
Estuarine and coastal hypoxia not only alters regional biogeochemical processes but also affects biodiversity and fisheries, which have attracted considerable attention globally. New study published in JGR Biogeosciences enable the understanding of the long-term patterns and possible mechanisms underlying hypoxia in large eutrophic estuaries and adjacent areas. Pictures: Pixabay.
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.
Seasonal changes in weather conditions drive the timing of the start and end of vegetation growth. The growing season has lengthened as a result of recent climatic warming, with the start of the growing season advancing more than the end of the growing season delaying. In a new study published in the journal Global Change Biology, authors proposed a phenology model that incorporates the constraints of temperature and radiation on vegetation productivity. Pictures: Pixabay.
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.
Vegetation changes have and important role in the seasonal budget of surface energy fluxes (biophysical feedbacks), 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. New study published in Nature Communications sheds light on their strong capacity to affect regional to global warming over annual or longer timescales. Pictures: Pixabay.
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.
Earth’s tree diversity is crucial for biodiversity and ecosystem functions and services. New study published in PNAS highlight the increasingly worrisome situation of forests; authors find that averagely ranges of 83% of tree species are exposed to non-negligible human pressure. Picture: Pixabay.
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:
assess range protection and
anthropogenic pressures for tree species
identify priority areas for conservation
of tree diversity considering multiple diversity dimensions
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,
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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.