| 1. |
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| 2. |
- Correa, D. F., et al.
(author)
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Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
- 2023
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:1, s. 49-69
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Journal article (peer-reviewed)abstract
- Aim To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period Tree-inventory plots established between 1934 and 2019. Major taxa studied Trees with a diameter at breast height (DBH) >= 9.55 cm. Location Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.
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| 3. |
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| 4. |
- Kattge, Jens, et al.
(author)
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TRY plant trait database - enhanced coverage and open access
- 2020
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In: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Journal article (peer-reviewed)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 5. |
- Eron, Joseph J., et al.
(author)
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Week 96 efficacy and safety results of the phase 3, randomized EMERALD trial to evaluate switching from boosted-protease inhibitors plus emtricitabine/tenofovir disoproxil fumarate regimens to the once daily, single-tablet regimen of darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) in treatment-experienced, virologically-suppressed adults living with HIV-1
- 2019
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In: Antiviral Research. - : Elsevier BV. - 0166-3542 .- 1872-9096. ; 170
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Journal article (peer-reviewed)abstract
- © 2019 The Authors Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg was investigated through 96 weeks in EMERALD (NCT02269917). Virologically-suppressed, HIV-1-positive treatment-experienced adults (previous non-darunavir virologic failure [VF] allowed) were randomized (2:1) to D/C/F/TAF or boosted protease inhibitor (PI) plus emtricitabine/tenofovir-disoproxil-fumarate (F/TDF) over 48 weeks. At week 52 participants in the boosted PI arm were offered switch to D/C/F/TAF (late-switch, 44 weeks D/C/F/TAF exposure). All participants were followed on D/C/F/TAF until week 96. Efficacy endpoints were percentage cumulative protocol-defined virologic rebound (PDVR; confirmed viral load [VL] ≥50 copies/mL) and VL < 50 copies/mL (virologic suppression) and ≥50 copies/mL (VF) (FDA-snapshot analysis). Of 1141 randomized patients, 1080 continued in the extension phase. Few patients had PDVR (D/C/F/TAF: 3.1%, 24/763 cumulative through week 96; late-switch: 2.3%, 8/352 week 52–96). Week 96 virologic suppression was 90.7% (692/763) (D/C/F/TAF) and 93.8% (330/352) (late-switch). VF was 1.2% and 1.7%, respectively. No darunavir, primary PI, tenofovir or emtricitabine resistance-associated mutations were observed post-baseline. No patients discontinued for efficacy-related reasons. Few discontinued due to adverse events (2% D/C/F/TAF arm). Improved renal and bone parameters were maintained in the D/C/F/TAF arm and observed in the late-switch arm, with small increases in total cholesterol/high-density-lipoprotein-cholesterol ratio. A study limitation was the lack of a control arm in the week 96 analysis. Through 96 weeks, D/C/F/TAF resulted in low PDVR rates, high virologic suppression rates, very few VFs, and no resistance development. Late-switch results were consistent with D/C/F/TAF week 48 results. EMERALD week 96 results confirm the efficacy, high genetic barrier to resistance and safety benefits of D/C/F/TAF.
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| 6. |
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| 7. |
- Muscarella, Robert, et al.
(author)
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The global abundance of tree palms
- 2020
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 29:9, s. 1495-1514
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Journal article (peer-reviewed)abstract
- AimPalms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change.LocationTropical and subtropical moist forests.Time periodCurrent.Major taxa studiedPalms (Arecaceae).MethodsWe assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure.ResultsOn average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work.ConclusionsTree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.
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| 8. |
- Beumer, B. R., et al.
(author)
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Impact of muscle mass on survival of patients with hepatocellular carcinoma after liver transplantation beyond the Milan criteria
- 2022
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In: Journal of Cachexia, Sarcopenia and Muscle. - : Wiley. - 2190-5991 .- 2190-6009. ; 13:5, s. 2373-2382
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Journal article (peer-reviewed)abstract
- Background: Access to the liver transplant waitlist for patients with hepatocellular carcinoma (HCC) depends on tumour presentation, biology, and response to treatments. The Milan Criteria (MC) represent the benchmark for expanded criteria that incorporate additional prognostic factors. The purpose of this study was to determine the added value of skeletal muscle index (SMI) in HCC patients beyond the MC. Method: Patients with HCC that were transplanted beyond the MC were included in this retrospective multicentre study. SMI was quantified using the Computed Tomography (CT) within 3months prior to transplantation. Cox regression models were used to identify predictors of overall survival (OS). The discriminative performance of SMI extended Metroticket 2.0 and AFP models was also assessed. Results: Out of 889 patients transplanted outside the MC, 528 had a CT scan within 3months prior to liver transplantation (LT), of whom 176 (33%) were classified as sarcopenic. The median time between assessment of the SMI and LT was 1.8months (IQR: 0.77–2.67). The median follow-up period was 5.1 95% CI [4.7–5.5] years, with a total of 177 recorded deaths from any cause. In a linear regression model with SMI as the dependent variable, only male gender (8.55 95% CI [6.51–10.59], P<0.001) and body mass index (0.74 95% CI [0.59–0.89], P<0.001) were significant. Univariable survival analysis of patients with sarcopenia versus patients without sarcopenia showed a significant difference in OS (HR 1.44 95% CI [1.07−1.94], P=0.018). Also the SMI was significant (HR 0.98 95% CI [0.96–0.99], P=0.014). The survival difference between the lowest SMI quartile versus the highest SMI quartile was significant (log-rank: P=0.005) with 5year OS of 57% and 71%, respectively. Data from 423 patients, describing 139 deaths, was used for multivariate analysis. Both sarcopenia (HR 1.45 95% CI [1.02−2.05], P=0.036) and SMI were (HR 0.98 95% CI [0.95–0.99], P=0.035) significant. On the survival scale this translates to a 5year OS difference of 11% between sarcopenia and no sarcopenia. Whereas for SMI, this translates to a survival difference of 8% between first and third quartiles for both genders. Conclusions: Overall, we can conclude that higher muscle mass contributes to a better long-term survival. However, for individual patients, low muscle mass should not be considered an absolute contra-indication for LT as its discriminatory performance was limited.
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| 9. |
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| 10. |
- Solana, E, et al.
(author)
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Regional grey matter microstructural changes and volume loss according to disease duration in multiple sclerosis patients
- 2021
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In: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1, s. 16805-
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Journal article (peer-reviewed)abstract
- The spatio-temporal characteristics of grey matter (GM) impairment in multiple sclerosis (MS) are poorly understood. We used a new surface-based diffusion MRI processing tool to investigate regional modifications of microstructure, and we quantified volume loss in GM in a cohort of patients with MS classified into three groups according to disease duration. Additionally, we investigated the relationship between GM changes with disease severity. We studied 54 healthy controls and 247 MS patients classified regarding disease duration: MS1 (less than 5 years, n = 67); MS2 (5–15 years, n = 107); and MS3 (more than15 years, n = 73). We compared GM mean diffusivity (MD), fractional anisotropy (FA) and volume between groups, and estimated their clinical associations. Regional modifications in diffusion measures (MD and FA) and volume did not overlap early in the disease, and became widespread in later phases. We found higher MD in MS1 group, mainly in the temporal cortex, and volume reduction in deep GM and left precuneus. Additional MD changes were evident in cingulate and occipital cortices in the MS2 group, coupled to volume reductions in deep GM and parietal and frontal poles. Changes in MD and volume extended to more than 80% of regions in MS3 group. Conversely, increments in FA, with very low effect size, were observed in the parietal cortex and thalamus in MS1 and MS2 groups, and extended to the frontal lobe in the later group. MD and GM changes were associated with white matter lesion load and with physical and cognitive disability. Microstructural integrity loss and atrophy present differential spatial predominance early in MS and accrual over time, probably due to distinct pathogenic mechanisms that underlie tissue damage.
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| 11. |
- Domínguez-Gil, B., et al.
(author)
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The Reality of Inadequate Patient Care and the Need for a Global Action Framework in Organ Donation and Transplantation
- 2022
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In: Transplantation. ; 106:11, s. 2111-2117
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Journal article (peer-reviewed)abstract
- BACKGROUND: Transplant therapy is considered the best and often the only available treatment for thousands of patients with organ failure that results from communicable and noncommunicable diseases. The number of annual organ transplants is insufficient for the worldwide need. METHODS: We elaborate the proceedings of the workshop entitled "The Role of Science in the Development of International Standards of Organ Donation and Transplantation," organized by the Pontifical Academy of Sciences and cosponsored by the World Health Organization in June 2021. RESULTS: We detail the urgency and importance of achieving national self-sufficiency in organ transplantation as a public health priority and an important contributor to reaching relevant targets of the United Nations Agenda for Sustainable Development. It details the elements of a global action framework intended for countries at every level of economic development to facilitate either the establishment or enhancement of transplant activity. It sets forth a proposed plan, by addressing the technical considerations for developing and optimizing organ transplantation from both deceased and living organ donors and the regulatory oversight of practices. CONCLUSIONS: This document can be used in governmental and policy circles as a call to action and as a checklist for actions needed to enable organ transplantation as treatment for organ failure. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.
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| 12. |
- Awan, Ahmed Arslan Yousuf, et al.
(author)
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Prevention, Diagnosis, Evaluation, and Treatment of Hepatitis C in Chronic Kidney Disease: Synopsis of the Kidney Disease: Improving Global Outcomes 2022 Clinical Practice Guideline
- 2023
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In: Annals of Internal Medicine. - : AMER COLL PHYSICIANS. - 0003-4819 .- 1539-3704. ; 176, s. 1648-1655
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Journal article (peer-reviewed)abstract
- Description: The Kidney Disease: Improving Global Outcomes (KDIGO) 2022 clinical practice guideline on prevention, diagnosis, evaluation, and treatment of hepatitis C in chronic kidney disease (CKD) is an update of the 2018 guideline from KDIGO.Methods: The KDIGO Work Group (WG) updated the guideline, which included reviewing and grading new evidence that was identified and summarized. As in the previous guideline, the WG used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach to appraise evidence and rate the strength of recommendations and used expert judgment to develop recommendations. New evidence led to updating of recommendations in the chapters on treatment of hepatitis C virus (HCV) infection in patients with CKD (Chapter 2), management of HCV infection before and after kidney transplant (Chapter 4), and diagnosis and management of kidney disease associated with HCV infection (Chapter 5). Recommendations in chapters on detection and evaluation of hepatitis C in CKD (Chapter 1) and prevention of HCV transmission in hemodialysis units (Chapter 3) were not updated because of an absence of significant new evidence.Recommendations: The 2022 updated guideline includes 43 graded recommendations and 20 ungraded recommendations, 7 of which are new or modified on the basis of the most recent evidence and consensus among the WG members. The updated guidelines recommend expanding treatment of hepatitis C with sofosbuvir-based regimens to patients with CKD glomerular filtration rate categories G4 and G5, including those receiving dialysis; expanding the donor pool for kidney transplant recipients by accepting HCV-positive kidneys regardless of the recipient's HCV status; and initiating direct-acting antiviral treatment of HCV-infected patients with clinical evidence of glomerulonephritis without requiring kidney biopsy. The update also addresses the use of immunosuppressive regimens in such patients.
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| 13. |
- Ferrari, P., et al.
(author)
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A bivariate measurement error model for nitrogen and potassium intakes to evaluate the performance of regression calibration in the European Prospective Investigation into Cancer and Nutrition study
- 2009
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In: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 1476-5640 .- 0954-3007. ; 63:4s, s. 179-187
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Journal article (peer-reviewed)abstract
- Objectives: Within the European Prospective Investigation into Cancer and Nutrition (EPIC) study, the performance of 24-h dietary recall (24-HDR) measurements as reference measurements in a linear regression calibration model is evaluated critically at the individual (within-centre) and aggregate (between-centre) levels by using unbiased estimates of urinary measurements of nitrogen and potassium intakes. Methods: Between 1995 and 1999, 1072 study subjects (59% women) from 12 EPIC centres volunteered to collect 24-h urine samples. Log-transformed questionnaire, 24-HDR and urinary measurements of nitrogen and potassium intakes were analysed in a multivariate measurement error model to estimate the validity of coefficients and error correlations in self-reported dietary measurements. In parallel, correlations between means of 24-HDR and urinary measurements were computed. Linear regression calibration models were used to estimate the regression dilution (attenuation) factors. Results: After adjustment for sex, centre, age, body mass index and height, the validity coefficients for 24-HDRs were 0.285 (95% confidence interval: 0.194, 0.367) and 0.371 (0.291, 0.446) for nitrogen and potassium intakes, respectively. The attenuation factors estimated in a linear regression calibration model were 0.368 (0.228, 0.508) for nitrogen and 0.500 (0.361, 0.639) for potassium intakes; only the former was different from the estimate obtained using urinary measurements in the measurement error model. The aggregate-level correlation coefficients between means of urinary and 24-HDR measurements were 0.838 (0.637, 0.932) and 0.756 (0.481, 0.895) for nitrogen and potassium intakes, respectively. Conclusions: This study suggests that 24-HDRs can be used as reference measurements at the individual and aggregate levels for potassium intake, whereas, for nitrogen intake, good performance is observed for between-centre calibration, but some limitations are apparent at the individual level. European Journal of Clinical Nutrition (2009) 63, S179-S187; doi: 10.1038/ejcn.2009.80
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| 14. |
- Householder, John Ethan, et al.
(author)
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One sixth of Amazonian tree diversity is dependent on river floodplains
- 2024
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In: NATURE ECOLOGY & EVOLUTION. - 2397-334X.
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Journal article (peer-reviewed)abstract
- Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.
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| 15. |
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| 16. |
- Luize, Bruno Garcia, et al.
(author)
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Geography and ecology shape the phylogenetic composition of Amazonian tree communities
- 2024
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In: JOURNAL OF BIOGEOGRAPHY. - 0305-0270 .- 1365-2699.
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Journal article (peer-reviewed)abstract
- Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and v & aacute;rzea forest types, the phylogenetic composition varies by geographic region, but the igap & oacute; and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R-2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R-2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions.
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| 17. |
- Malhi, Yadvinder, et al.
(author)
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The Global Ecosystems Monitoring network : Monitoring ecosystem productivity and carbon cycling across the tropics
- 2021
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In: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 253
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Journal article (peer-reviewed)abstract
- A rich understanding of the productivity, carbon and nutrient cycling of terrestrial ecosystems is essential in the context of understanding, modelling and managing the future response of the biosphere to global change. This need is particularly acute in tropical ecosystems, home to over 60% of global terrestrial productivity, over half of planetary biodiversity, and hotspots of anthropogenic pressure. In recent years there has been a surge of activity in collecting data on the carbon cycle, productivity, and plant functional traits of tropical ecosystems, most intensively through the Global Ecosystems Monitoring network (GEM). The GEM approach provides valuable insights by linking field-based ecosystem ecology with the needs of Earth system science. In this paper, we review and synthesize the context, history and recent scientific output from the GEM network. Key insights have emerged on the spatial and temporal variability of ecosystem productivity and on the role of temperature and drought stress on ecosystem function and resilience. New work across the network is now linking carbon cycling to nutrient cycling and plant functional traits, and subsequently to airborne remote sensing. We discuss some of the novel emerging patterns and practical and methodological challenges of this approach, and examine current and possible future directions, both within this network and as lessons for a more general terrestrial ecosystem observation scheme.
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| 18. |
- Martin, Paul, et al.
(author)
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Executive Summary of the KDIGO 2022 Clinical Practice Guideline for the Prevention, Diagnosis, Evaluation, and Treatment of Hepatitis C in Chronic Kidney Disease
- 2022
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In: Kidney International. - : ELSEVIER SCIENCE INC. - 0085-2538 .- 1523-1755. ; 102:6, s. 1228-1237
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Journal article (peer-reviewed)abstract
- Infection with the hepatitis C virus (HCV) has adverse liver, kidney, and cardiovascular consequences in patients with chronic kidney disease (CKD), including those on dialysis therapy or with a kidney transplant. Since the publication of the Kidney Disease: Improving Global Outcomes (KDIGO) HCV Guideline in 2018, advances in HCV management, particularly in the field of antiviral therapy and treatment of HCV-associated glomerular diseases, coupled with increased usage of HCV-positive kidney grafts, have prompted a reexamination of the 2018 guideline. As a result, the Work Group performed a comprehensive review and revised the 2018 guidance. This Executive Summary highlights key aspects of the updated guideline recommendations for 3 chapters: Chapter 2: Treatment of HCV infection in patients with CKD; Chapter 4: Management of HCV-infected patients before and after kidney transplantation; and Chapter 5: Diagnosis and management of kidney diseases associated with HCV infection.
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| 19. |
- Rifai, Sami W., et al.
(author)
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ENSO Drives interannual variation of forest woody growth across the tropics
- 2018
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In: Philosophical Transactions of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2970 .- 0962-8436. ; 373:1760
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Journal article (peer-reviewed)abstract
- Meteorological extreme events such as El Niño events are expected to affect tropical forest net primary production (NPP) and woody growth, but there has been no large-scale empirical validation of this expectation. We collected a large high-temporal resolution dataset (for 1-13 years depending upon location) of more than 172 000 stem growth measurements using dendrometer bands from across 14 regions spanning Amazonia, Africa and Borneo in order to test how much month-to-month variation in stand-level woody growth of adult tree stems (NPPstem) can be explained by seasonal variation and interannual meteorological anomalies. A key finding is that woody growth responds differently to meteorological variation between tropical forests with a dry season (where monthly rainfall is less than 100 mm), and aseasonal wet forests lacking a consistent dry season. In seasonal tropical forests, a high degree of variation in woody growth can be predicted from seasonal variation in temperature, vapour pressure deficit, in addition to anomalies of soil water deficit and shortwave radiation. The variation of aseasonal wet forest woody growth is best predicted by the anomalies of vapour pressure deficit, water deficit and shortwave radiation. In total, we predict the total live woody production of the global tropical forest biome to be 2.16 Pg C yr-1, with an interannual range 1.96-2.26 Pg C yr-1 between 1996-2016, and with the sharpest declines during the strong El Niño events of 1997/8 and 2015/6. There is high geographical variation in hotspots of El Niño-associated impacts, with weak impacts in Africa, and strongly negative impacts in parts of Southeast Asia and extensive regions across central and eastern Amazonia. Overall, there is high correlation (r = -0.75) between the annual anomaly of tropical forest woody growth and the annual mean of the El Niño 3.4 index, driven mainly by strong correlations with anomalies of soil water deficit, vapour pressure deficit and shortwave radiation.This article is part of the discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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| 20. |
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| 21. |
- ter Steege, Hans, et al.
(author)
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Mapping density, diversity and species-richness of the Amazon tree flora
- 2023
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In: COMMUNICATIONS BIOLOGY. - 2399-3642. ; 6:1
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Journal article (peer-reviewed)abstract
- Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution. A study mapping the tree species richness in Amazonian forests shows that soil type exerts a strong effect on species richness, probably caused by the areas of these forest types. Cumulative water deficit, tree density and temperature seasonality affect species richness at a regional scale.
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| 22. |
- Vedovato, Laura B., et al.
(author)
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Ancient fires enhance Amazon forest drought resistance
- 2023
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In: Frontiers in Forests and Global Change. - : Frontiers Media SA. - 2624-893X. ; 6
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Journal article (peer-reviewed)abstract
- Drought and fire reduce productivity and increase tree mortality in tropical forests. Fires also produce pyrogenic carbon (PyC), which persists in situ for centuries to millennia, and represents a legacy of past fires, potentially improving soil fertility and water holding capacity and selecting for the survival and recruitment of certain tree life-history (or successional) strategies. We investigated whether PyC is correlated with physicochemical soil properties, wood density, aboveground carbon (AGC) dynamics and forest resistance to severe drought. To achieve our aim, we used an Amazon-wide, long-term plot network, in forests without known recent fires, integrating site-specific measures of forest dynamics, soil properties and a unique soil PyC concentration database. We found that forests with higher concentrations of soil PyC had both higher soil fertility and lower wood density. Soil PyC was not associated with AGC dynamics in non-drought years. However, during extreme drought events (10% driest years), forests with higher concentrations of soil PyC experienced lower reductions in AGC gains (woody growth and recruitment), with this drought-immunizing effect increasing with drought severity. Forests with a legacy of ancient fires are therefore more likely to continue to grow and recruit under increased drought severity. Forests with high soil PyC concentrations (third quartile) had 3.8% greater AGC gains under mean drought, but 33.7% greater under the most extreme drought than forests with low soil PyC concentrations (first quartile), offsetting losses of up to 0.68 Mg C ha–1yr–1 of AGC under extreme drought events. This suggests that ancient fires have legacy effects on current forest dynamics, by altering soil fertility and favoring tree species capable of continued growth and recruitment during droughts. Therefore, mature forest that experienced fires centuries or millennia ago may have greater resistance to current short-term droughts.
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| 23. |
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| 24. |
- Agudo, Antonio, et al.
(author)
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Polymorphisms in metabolic genes related to tobacco smoke and the risk of gastric cancer in the European prospective investigation into cancer and nutrition
- 2006
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In: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 15:12, s. 2427-2434
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Journal article (peer-reviewed)abstract
- Metabolizing enzymes, which often display genetic polymorphisms, are involved in the activation of compounds present in tobacco smoke that may be relevant to gastric carcinogenesis. We report the results of a study looking at the association between risk of gastric adenocarcinoma and polymorphisms in genes CYP1A1, CYP1A2, EPHX1, and GSTT1. A nested case-control study was carried out within the European Prospective Investigation into Cancer and Nutrition, developed in 10 European countries. The study includes 243 newly diagnosed cases of histologically confirmed gastric adenocarcinoma and 946 controls matched by center, age, sex, and date of blood collection. Genotypes were determined in nuclear DNA from WBCs. We found an increased risk of gastric cancer for homozygotes for C (histidine) variant in Y113H of EPHX1 (odds ratio, 1.91; 95% confidence interval, 1.19-3.07) compared with subjects with TC/TT. There was also a significant increased risk for smokers carrying at least one variant allele A in Ex7+129C > A (m4) of CYP1A1 and never smokers with null GSTT1 and allele A in the locus -3859G > A of CYP1A2. Most of these genes are involved in the activation and detoxification of polycyclic aromatic hydrocarbons, suggesting a potential role of these compounds in gastric carcinogenesis.
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