Journal: Global Change Biology

Abbreviation

Glob. Chang. Biol.

Publisher

Wiley-Blackwell

Journal Volumes

ISSN

1354-1013
1365-2486

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Publications 1 - 10 of 135
  • Century-long apparent decrease in intrinsic water-use efficiency with no evidence of progressive nutrient limitation in African tropical forests
    Item type: Journal Article
    Bauters, Marijn; Meeus, Sofie; Barthel, Matti; et al. (2020)
    Global Change Biology
    Forests exhibit leaf‐ and ecosystem‐level responses to environmental changes. Specifically, rising carbon dioxide (CO2) levels over the past century are expected to have increased the intrinsic water‐use efficiency (iWUE) of tropical trees while the ecosystem is gradually pushed into progressive nutrient limitation. Due to the long‐term character of these changes, however, observational datasets to validate both paradigms are limited in space and time. In this study, we used a unique herbarium record to go back nearly a century and show that despite the rise in CO2 concentrations, iWUE has decreased in central African tropical trees in the Congo Basin. Although we find evidence that points to leaf‐level adaptation to increasing CO2—that is, increasing photosynthesis‐related nutrients and decreasing maximum stomatal conductance, a decrease in leaf δ13C clearly indicates a decreasing iWUE over time. Additionally, the stoichiometric carbon to nitrogen and nitrogen to phosphorus ratios in the leaves show no sign of progressive nutrient limitation as they have remained constant since 1938, which suggests that nutrients have not increasingly limited productivity in this biome. Altogether, the data suggest that other environmental factors, such as increasing temperature, might have negatively affected net photosynthesis and consequently downregulated the iWUE. Results from this study reveal that the second largest tropical forest on Earth has responded differently to recent environmental changes than expected, highlighting the need for further on‐ground monitoring in the Congo Basin.
  • Simulated and observed fluxes of sensible and latent heat and CO2 at the WLEF-TV tower using SiB2.5
    Item type: Journal Article
    Baker, Ian; Denning, A. Scott; Hanan, Niall; et al. (2003)
    Global Change Biology
  • Integrating plant litter quality, soil organic matter stabilization, and the carbon saturation concept
    Item type: Journal Article
    Castellano, Michael J.; Mueller, Kevin E.; Olk, Daniel C.; et al. (2015)
    Global Change Biology
  • No Future Growth Enhancement Expected at the Northern Edge for European Beech due to Continued Water Limitation
    Item type: Journal Article
    Klesse, Stefan; Peters, Richard L.; Alfaro-Sánchez, Raquel; et al. (2024)
    Global Change Biology
    With ongoing global warming, increasing water deficits promote physiological stress on forest ecosystems with negative impacts on tree growth, vitality, and survival. How individual tree species will react to increased drought stress is therefore a key research question to address for carbon accounting and the development of climate change mitigation strategies. Recent tree-ring studies have shown that trees at higher latitudes will benefit from warmer temperatures, yet this is likely highly species-dependent and less well-known for more temperate tree species. Using a unique pan-European tree-ring network of 26,430 European beech (Fagus sylvatica L.) trees from 2118 sites, we applied a linear mixed-effects modeling framework to (i) explain variation in climate-dependent growth and (ii) project growth for the near future (2021–2050) across the entire distribution of beech. We modeled the spatial pattern of radial growth responses to annually varying climate as a function of mean climate conditions (mean annual temperature, mean annual climatic water balance, and continentality). Over the calibration period (1952–2011), the model yielded high regional explanatory power (R² = 0.38–0.72). Considering a moderate climate change scenario (CMIP6 SSP2-4.5), beech growth is projected to decrease in the future across most of its distribution range. In particular, projected growth decreases by 12%–18% (interquartile range) in northwestern Central Europe and by 11%–21% in the Mediterranean region. In contrast, climate-driven growth increases are limited to around 13% of the current occurrence, where the historical mean annual temperature was below ~6°C. More specifically, the model predicts a 3%–24% growth increase in the high-elevation clusters of the Alps and Carpathian Arc. Notably, we find little potential for future growth increases (−10 to +2%) at the poleward leading edge in southern Scandinavia. Because in this region beech growth is found to be primarily water-limited, a northward shift in its distributional range will be constrained by water availability.
  • Driving factors of a vegetation shift from Scots pine to pubescent oak in dry Alpine forests
    Item type: Journal Article
    Rigling, Andreas; Bigler, Christof; Eilmann, Britta; et al. (2013)
    Global Change Biology
  • Nitrogen input mediates the effect of free-air CO2 enrichment on mycorrhizal fungal abundance
    Item type: Journal Article
    Staddon, Philip L.; Jakobsen, Iver; Blum, Herbert (2004)
    Global Change Biology
  • Simple additive effects are rare
    Item type: Review Article
    Dieleman, W. I. J.; Vicca, S.; Dijkstra, F. A.; et al. (2012)
    Global Change Biology
  • ForestTemp – Sub-canopy microclimate temperatures of European forests
    Item type: Journal Article
    Haesen, Stef; Lembrechts, Jonas J.; De Frenne, Pieter; et al. (2021)
    Global Change Biology
    Ecological research heavily relies on coarse-gridded climate data based on standardized temperature measurements recorded at 2 m height in open landscapes. However, many organisms experience environmental conditions that differ substantially from those captured by these macroclimatic (i.e. free air) temperature grids. In forests, the tree canopy functions as a thermal insulator and buffers sub-canopy microclimatic conditions, thereby affecting biological and ecological processes. To improve the assessment of climatic conditions and climate-change-related impacts on forest-floor biodiversity and functioning, high-resolution temperature grids reflecting forest microclimates are thus urgently needed. Combining more than 1200 time series of in situ near-surface forest temperature with topographical, biological and macroclimatic variables in a machine learning model, we predicted the mean monthly offset between sub-canopy temperature at 15 cm above the surface and free-air temperature over the period 2000-2020 at a spatial resolution of 25 m across Europe. This offset was used to evaluate the difference between microclimate and macroclimate across space and seasons and finally enabled us to calculate mean annual and monthly temperatures for European forest understories. We found that sub-canopy air temperatures differ substantially from free-air temperatures, being on average 2.1 degrees C (standard deviation +/- 1.6 degrees C) lower in summer and 2.0 degrees C higher (+/- 0.7 degrees C) in winter across Europe. Additionally, our high-resolution maps expose considerable microclimatic variation within landscapes, not captured by the gridded macroclimatic products. The provided forest sub-canopy temperature maps will enable future research to model below-canopy biological processes and patterns, as well as species distributions more accurately.
  • Extreme weather-year sequences have nonadditive effects on environmental nitrogen losses
    Item type: Journal Article
    Iqbal, Javed; Necpálová, Magdalena; Archontoulis, Sotirios V.; et al. (2018)
    Global Change Biology
  • Long‐term changes in forest response to extreme atmospheric dryness
    Item type: Journal Article
    Shekhar, Ankit; Hörtnagl, Lukas; Buchmann, Nina; et al. (2023)
    Global Change Biology
    Atmospheric dryness, as indicated by vapor pressure deficit (VPD), has a strong influence on forest greenhouse gas exchange with the atmosphere. In this study, we used long-term (10–30 years) net ecosystem productivity (NEP) measurements from 60 forest sites across the world (1003 site-years) to quantify long-term changes in forest NEP resistance and NEP recovery in response to extreme atmospheric dryness. We tested two hypotheses: first, across sites differences in NEP resistance and NEP recovery of forests will depend on both the biophysical characteristics (i.e., leaf area index [LAI] and forest type) of the forest as well as on the local meteorological conditions of the site (i.e., mean VPD of the site), and second, forests experiencing an increasing trend in frequency and intensity of extreme dryness will show an increasing trend in NEP resistance and NEP recovery over time due to emergence of long-term ecological stress memory. We used a data-driven statistical learning approach to quantify NEP resistance and NEP recovery over multiple years. Our results showed that forest types, LAI, and median local VPD conditions explained over 50% of variance in both NEP resistance and NEP recovery, with drier sites showing higher NEP resistance and NEP recovery compared to sites with less atmospheric dryness. The impact of extreme atmospheric dryness events on NEP lasted for up to 3 days following most severe extreme events in most forests, indicated by an NEP recovery of less than 100%. We rejected our second hypothesis as we found no consistent relationship between trends of extreme VPD with trends in NEP resistance and NEP recovery across different forest sites, thus an increase in atmospheric dryness as it is predicted might not increase the resistance or recovery of forests in terms of NEP.
Publications 1 - 10 of 135