Publications by authors named "Tobias Gebauer"

While studies have demonstrated that higher tree species richness can increase forest productivity, the relationships between tree species richness, tree growth and herbivore damage remain insufficiently explored. Here we investigate these linkages using data from 8,790 trees across 80 species in 9 biodiversity experiments, spanning temperate and subtropical biomes. Despite considerable geographic variation, we reveal an overall positive relationship between tree species richness and insect herbivory, as well as between tree growth and herbivory, at individual, species and community levels.

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International commitments advocate large-scale forest restoration as a nature-based solution to climate change mitigation through carbon (C) sequestration. Mounting evidence suggests that mixed compared to monospecific planted forests may sequester more C, exhibit lower susceptibility to climate extremes and offer a broader range of ecosystem services. However, experimental studies comprehensively examining the control of tree diversity on multiple C stocks and fluxes above- and belowground are lacking.

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Article Synopsis
  • Recent droughts are worsening and expected to affect forest ecosystems more frequently and intensely due to climate change.
  • Research shows that having more tree species in a plantation can reduce the stress on trees during drought events, reflected by changes in leaf carbon and nitrogen isotopes.
  • Higher tree species richness leads to lower drought stress (lower leaf δC) and changes in nitrogen cycling during drought (higher leaf δN), indicating that diverse tree plantations might perform better under severe drought conditions.
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Plant diversity effects on community productivity often increase over time. Whether the strengthening of diversity effects is caused by temporal shifts in species-level overyielding (i.e.

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Article Synopsis
  • Climate change is making droughts (periods without rain) happen more often and for longer periods of time, which is bad for ecosystems.
  • Scientists did a big experiment in many places around the world to see how one year of drought affects grasslands and shrublands.
  • They found that extreme drought can reduce plant growth much more than expected, especially in dry areas with fewer types of plants, showing that these places are more at risk.
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Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk.

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Article Synopsis
  • Droughts significantly impact grassland productivity and biodiversity, and nutrient availability may play a key role in these varying responses.
  • A standardized nutrient addition experiment in 10 European grasslands showed that adding nitrogen, phosphorus, and potassium worsened drought effects on plant biomass, particularly harming graminoids (grasses) while forbs (broadleaf plants) were less affected.
  • Understanding how nutrients influence drought effects can help improve agricultural management strategies, considering that fertilized versus unfertilized grasslands offer different ecosystem services.
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Variations in crown forms promote canopy space-use and productivity in mixed-species forests. However, we have a limited understanding on how this response is mediated by changes in within-tree biomass allocation. Here, we explored the role of changes in tree allometry, biomass allocation and architecture in shaping diversity-productivity relationships (DPRs) in the oldest tropical tree diversity experiment.

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We examined root hydraulic conductivity (L(p)) responses of one-year-old seedlings of four conifers to the combined effects of elevated CO2 and inorganic nitrogen (N) sources. We found marked interspecific differences in L(p) responses to high CO2 ranging from a 37% increase in P. abies to a 27% decrease in P.

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Forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. We used Granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven broad-leaved tree species differing in wood density and xylem structure. Study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous trees and (2) analyze the relationship between hydro-active sapwood area and stem diameter.

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