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Plants store large amounts of non-structural carbohydrates (NSC). While multiple functions of NSC have long been recognized, the interpretation of NSC seasonal dynamics is often based on the idea that stored NSC is a reservoir of carbon that fluctuates depending on the balance between supply via photosynthesis and demand for growth and respiration (the source–sink dynamics concept). Consequently, relatively high NSC concentrations in some plants have been interpreted to reflect excess supply relative to demand. An alternative view, however, is that NSC accumulation reflects the relatively high NSC levels required for plant survival; an important issue that remains highly controversial. Here, we assembled a new global database to examine broad patterns of seasonal NSC variation across organs (leaves, stems, and belowground), plant functional types (coniferous, drought-deciduous angiosperms, winter deciduous angiosperms, evergreen angiosperms, and herbaceous) and biomes (boreal, temperate, Mediterranean, and tropical). We compiled data from 121 studies, including seasonal measurements for 177 species under natural conditions. Our results showed that, on average, NSC account for ~10% of dry plant biomass and are highest in leaves and lowest in stems, whereas belowground organs show intermediate concentrations. Total NSC, starch, and soluble sugars (SS) varied seasonally, with a strong depletion of starch during the growing season and a general increase during winter months, particularly in boreal and temperate biomes. Across functional types, NSC concentrations were highest and most variable in herbaceous species and in conifer needles. Conifers showed the lowest stem and belowground NSC concentrations. Minimum NSC values were relatively high (46% of seasonal maximums on average for total NSC) and, in contrast to average values, were similar among biomes and functional types. Overall, although starch depletion was relatively common, seasonal depletion of total NSC or SS was rare. These results are consistent with a dual view of NSC function: whereas starch acts mostly as a reservoir for future use, soluble sugars perform immediate functions (e.g., osmoregulation) and are kept above some critical threshold. If confirmed, this dual function of NSC will have important implications for the way we understand and model plant carbon allocation and survival under stress.

Globally accelerating trends in societal development and human environmental impacts since the mid-twentieth century 1 – 7 are known as the Great Acceleration and have been discussed as a key indicator of the onset of the Anthropocene epoch 6 . While reports on ecological responses (for example, changes in species range or local extinctions) to the Great Acceleration are multiplying 8 , 9 , it is unknown whether such biotic responses are undergoing a similar acceleration over time. This knowledge gap stems from the limited availability of time series data on biodiversity changes across large temporal and geographical extents. Here we use a dataset of repeated plant surveys from 302 mountain summits across Europe, spanning 145 years of observation, to assess the temporal trajectory of mountain biodiversity changes as a globally coherent imprint of the Anthropocene. We find a continent-wide acceleration in the rate of increase in plant species richness, with five times as much species enrichment between 2007 and 2016 as fifty years ago, between 1957 and 1966. This acceleration is strikingly synchronized with accelerated global warming and is not linked to alternative global change drivers. The accelerating increases in species richness on mountain summits across this broad spatial extent demonstrate that acceleration in climate-induced biotic change is occurring even in remote places on Earth, with potentially far-ranging consequences not only for biodiversity, but also for ecosystem functioning and services. Analysis of changes in plant species richness on mountain summits over the past 145 years suggests that increased climatic warming has led to an acceleration in species richness increase.

Cardiac magnetic resonance (CMR) offers the capability to objectively detect pericarditis by identifying pericardial thickening, edema/inflammation by Short-TI Inversion Recovery-T2 weighted (STIR-T2w) imaging, edema/inflammation or fibrosis by late gadolinium enhancement (LGE), and presence of pericardial effusion. This is especially helpful for the diagnosis of recurrent pericarditis. Aim of the present paper is to assess the diagnostic accuracy of CMR findings as well as their potential prognostic value for the diagnosis of recurrent pericarditis. Multicenter cohort study of consecutive patients with recurrent pericarditis evaluated by CMR. We included 128 consecutive cases (60 males, 47%; mean age 48 ± 14 years). CMR was performed at a mean time of 12 days (95% confidence interval 15 to 21) after the clinical diagnosis. We evaluated the diagnostic accuracy and areas under the receiver operating characteristic (ROC) curve for CMR diagnostic criteria and complications (additional recurrences, cardiac tamponade, and constrictive pericarditis). Areas under the ROC curve were respectively 64% for pericardial thickening, 84% for pericardial edema, 82% for pericardial LGE, and 71% for pericardial effusion. After a mean follow-up of 34 months, recurrences occurred in 52% of patients, tamponade in 6%, and constrictive pericarditis in 11%. Using a multivariable Cox model, elevation of CRP and presence of CMR pericardial thickening were predictors of adverse events, whereas the presence of CMR LGE was associated with a lower risk. The prognostic model for adverse events using gender, age, CRP level, and all CMR variables showed a C-index of 0.84. In conclusion, CMR findings show high diagnostic accuracy and may help identifying patients at higher risk of complications.

Reduced productivity of trees after defoliation might be caused by limited carbon (C) availability. We investigated the combined effect of different atmospheric CO2 concentrations (160, 280 and 560 ppm) and early season defoliation on the growth and C reserves (nonstructural carbohydrates (NSC)) of saplings of two oak species with different leaf habits (deciduous Quercus petraea and evergreen Quercus ilex). In both species, higher CO2 supply significantly enhanced growth. Defoliation had a strong negative impact on growth (stronger for Q. ilex), but the relative reduction of growth caused by defoliation within each CO2 treatment was very similar across all three CO2 concentrations. Low CO2 and defoliation led to decreased NSC tissue concentrations mainly in the middle of the growing season in Q. ilex, but not in Q. petraea. However, also in Q. ilex, NSC increased in woody tissues in defoliated and low-CO2 saplings towards the end of the growing season. Although the saplings were C limited under these specific experimental conditions, growth reduction after defoliation was not directly caused by C limitation. Rather, growth of trees followed a strong allometric relationship between total leaf area and conductive woody tissue, which did not change across species, CO2 concentrations and defoliation treatments.

This research was supported by the Spanish Government projects CGL2013-48074-P, AGL 2012-40039-C02 and AGL 2012- 40151-C03, the Catalan Government project SGR 2014-274 and the European Research Council Synergy grant ERC-2013- SyG-610028 IMBALANCE-P. The Spanish Government funded the FPU predoctoral fellowship to P.M-G., the FPI predoctoral fellowship and travel grant to A.B., and the Ram on y Cajal Programme to J.P.F. (RYC-2008-02050) and S.P. (RYC- 2013-14164).

Extreme environments, whether defined by climate, soils, or disturbance, at landscape or micro‐scales, are prevalent across Earth's surface and have long served as crucibles for ecological and evolutionary insights. Many foundational theories were developed in deserts, cliffs, ultramafic soils, and other harsh systems. Yet, these environments are usually studied in siloed, discipline‐ or ecosystem‐specific contexts, rather than as part of a generalizable macroecological model. Here, we propose reframing extreme environments as a unifying framework for ecology, one that can explore the boundaries of ecological processes, detect the limits of functional trait strategies, and improve predictions of ecosystem responses to emerging global extremes. We also revisit key ecological concepts, including species coexistence, succession, spatial ecology, and functional trait theory, through the lens of extreme environments, and identify emerging research opportunities that arise when these systems are treated as central to, rather than siloed in, ecological theory. Rather than exceptions or outliers, these systems should be recognized as central to understanding the resilience, adaptability, and future trajectories of life on Earth.

Gypsum soils are among the most restrictive and widespread substrates for plant life. Plants living on gypsum are classified as gypsophiles (exclusive to gypsum) and gypsovags (non-exclusive to gypsum). The former have been separated into wide and narrow gypsophiles, each with a putative different ecological strategy. Mechanisms displayed by gypsum plants to compete and survive on gypsum are still not fully understood. The aim of this study was to compare the main chemical groups in the leaves of plants with different specificity to gypsum soils and to explore the ability of Fourier transform infrared (FTIR) spectra analyzed with neural network (NN) modelling to discriminate groups of gypsum plants. Leaf samples of 14 species with different specificity to gypsum soils were analysed with FTIR spectroscopy coupled to neural network (NN) modelling. Spectral data were further related to the N, C, S, P, K, Na, Ca, Mg and ash concentrations of samples. The FTIR spectra of the three groups analyzed showed distinct features that enabled their discrimination through NN models. Wide gypsophiles stood out for the strong presence of inorganic compounds in their leaves, particularly gypsum and, in some species, also calcium oxalate crystals. The spectra of gypsovags had less inorganic chemical species, while those of narrow gypsum endemisms had low inorganics but shared with wide gypsophiles the presence of oxalate. Gypsum and calcium oxalate crystals seem to be widespread amongst gypsum specialist plants, possibly as a way to tolerate excess Ca and sulphate. However, other mechanisms such as the accumulation of sulphates in organic molecules are also compatible with plant specialization to gypsum. While gypsovags seem to be stress tolerant plants that tightly regulate the uptake of S and Ca, the ability of narrow gypsum endemisms to accumulate excess Ca as oxalate may indicate their incipient specialization to gypsum.

Key message Seasonal dynamics of branch carbohydrates differed sharply between coexisting evergreen and deciduous Mediterranean oaks. Branch carbon storage was crucial in the evergreen, while it played a minor role in the deciduous oaks. The aim of this study was to describe the seasonal dynamics of nutrients and NSC in relation to the aboveground phenology of coexisting winter-deciduous ( Quercus faginea ) and evergreen ( Quercus ilex subsp. ballota ) oak species, and to analyse the relationship between the resource budget of branches and shoot growth. Monthly concentrations of nitrogen (N), phosphorus (P), potassium (K) and non-structural carbohydrates (NSC) plus the aboveground phenology of branches were measured over 2 years. We also analysed the correlation between the resource budget of branches prior to the growing season and the subsequent shoot and stem growth. Seasonal branch nutrient dynamics could be explained by shoot growth phenology, showing similar patterns across species. However, NSC dynamics varied between the two species, owing to the differences in leaf phenology and the contrasting role of branches as storage sites. NSC and N branch storage were crucial for the early stages of shoot growth in the evergreen trees. Accordingly, branch N and NSC storage pools in late winter correlated positively with spring growth, and NSC concentrations dropped during bud burst in all branch organs of Q. ilex . Contrastingly, branch NSC concentrations of the deciduous Q. faginea were only marginally affected by spring growth and no relationship was observed between branch N and NSC stores prior to bud burst. These results challenge previous assumptions on the lower relevance of branch NSC storage for the spring growth of evergreen trees and call for further studies where closely related pairs of coexisting evergreen and deciduous tree species are compared.

This paper introduces gypsum ecosystem research to southern Africa. It is the result of current joint efforts to compare African gypsum ecosystems with those in other parts of the world. We highlight the expansion of an international network through joint projects and training of young scientists. We propose a research agenda to sensitise the ecological community in Africa to the significance of life on gypsum and to demystify the existence of gypsum soil and associated ecosystems in southern Africa. Gypsum ecosystem research is rapidly moving up the international research agenda to better understand the dynamics and resilience of the life systems associated with atypical soils that are frequent in semi-arid to arid ecosystems. The southern African soil classification system does not sufficiently recognise the presence of gypsum as a differentiating criterion, hence not much is known about the region's gypsum soil, and gypsum ecology has subsequently been largely neglected. This neglect is unfortunate, as the livelihoods of people are dependent on these gypsum ecosystems and these areas are worthy of protection due to the rare biotas that are adapted to survive in these harsh environments. One of the key players in gypsum ecosystem research, GYPWORLD (a European H2020-MSCA-RISE GYPWORLD project), approached the GeoEco Lab at the North-West University (NWU) to arrange a first research expedition to major gypsum areas of southern Africa, with a specific focus on the central Namib Desert of Namibia and Namaqualand in the northern Cape, South Africa. The goals of GYPWORLD are to (1) assess plant and lichen diversity associated with gypsum soils; (2) determine the origin of gypsophilic biotas worldwide; (3) understand the processes that regulate plant and lichen ecosystem function; (4) promote the study of gypsum ecosystems; and (5) communicate the ecological and conservation value of these ecosystems to the public. The expedition from 12 August to 4 September 2022 was attended by 26 experts from Brazil, Namibia, South Africa, Spain, Turkey, and the USA. Participating researchers exchanged skills and knowledge during the expedition and in two public seminars. The seminars provided opportunities for scientists to network and discuss research related to plant, lichen and community dynamics and conservation. The first was hosted by the Unit for Environmental Sciences and Management at NWU on 11 August 2022, and the second by the Gobabeb Namib Research Institute on 23 August 2022. Delegates provided background information on southern Africa's gypsum ecosystems and discussed leading international research dealing with gypsum ecology and associated lichen and plant communities. Two invited Fulbright US Scholars, who are specialists on life in harsh environments, contributed to the discussion about the state of gypsum research in southern Africa, including current knowledge gaps. Young scientists participated to stimulate their thinking on the links between diversity, function, evolutionary history, and disturbance in these ecosystems and contributed interesting perspectives to the discussions. The seminar participants emphasised that significant knowledge gaps in gypsum characteristics preclude assumptions about the age, origin and ecological significance of the pedogenic gypsum soils along Africa's southwestern coast. A lack of in-depth local knowledge regarding gypsum indicator species, particularly distinguishing between gypsophiles (endemic - restricted to gypsum) and gypsovags (those on both gypsum and non-gypsum soils), when studying gypsum ecology and community assembly, were also highlighted.