Biology subjects

Schellenberger Costa, D.

Publications and source records attributed to Schellenberger Costa, D..

3 recordsLinked to original sources

bioRxiv2026

Stomatal sensitivity to VPD across 38 tree species reflects past drought responses but is little explained by stomatal and leaf economic traits

Climate change is exposing trees to rising atmospheric water demand. Because stomata regulate plant water loss, understanding stomatal behaviour is critical. However, few comparative studies examine species-specific stomatal responses to atmospheric demand. Here, we quantify stomatal behaviour in 38 temperate tree species (27 broadleaved, 11 conifers) in a German research arboretum during a warm summer without soil drought. We measured the diurnal stomatal conductance (gs) of 787 leaves and modelled gs species-specific responses to leaf-to-air vapour pressure deficit (VPDL). Four descriptors of the gs-VPDL relationship were derived: maximum stomatal conductance (gmax), the VPDL that maximises gs, the VPDL associated with a 50% reduction in gs, and the stomatal closure rate. We relate these metrics to drought-induced shifts of carbon isotope ratios and to leaf functional traits. Large variation in stomatal behaviour exists, ranging from early-closure to VPDL-tolerant strategies. Species maintaining gs at higher VPDL also show weaker physiological responses to past drought. gmax is partly explained by leaf economic traits; other gs-VPDL descriptors are not related to stomatal anatomy and leaf economy. Our interspecific comparison reveals substantial variation in stomatal responses to atmospheric demand that is relevant to drought responses, but cannot be readily inferred from commonly measured leaf traits.

ecology↗

bioRxiv2026

Global Convergence of Plant Functional Trait Composition in the Anthropocene

Since the onset of European colonial expansion, humans have accelerated species migration across continents, reshaping plant functional composition and associated ecosystem processes. Plant functional traits-such as leaf area, plant height, or rooting depth-are structured along major axes of variation, including size and leaf economics, that reflect ecological strategies. While human-mediated changes in this trait space have been documented regionally or for specific taxa, there exists no global, grid cell-level quantification of past shifts across major axes of trait variation. Here, we link global citizen science plant occurrence data with data on 37 above- and below-ground traits, and information on native and introduced status for each occurrence. Using dimension-reduction on grid cell-level trait means and introduced species status as a proxy for anthropogenic change, we identify three major axes of functional variation: the size, leaf economics, and life-span axes. By comparing past (native-only) and present-day trait distributions in 3D trait space and geographically, we find prominent region-specific shifts along all three axes. Overall, functional composition converges toward (mostly) smaller, more acquisitive, and shorter-lived assemblages, with region-specific differences in which axis shifts are most pronounced. These results provide the first global estimate of how human-mediated plant introductions have altered ecosystem functional composition in the past centuries, highlighting the spatial patterns and trait dimensions most affected by anthropogenic pressures.

ecology↗

bioRxiv2025

Community-level plant functional strategies explain ecosystem carbon storage across a tropical elevational gradient

1. Plant functional traits play an important role in shaping plant ecological responses to environmental conditions and influencing ecosystem functioning. However, how whole-plant functional strategies manifest at the community level to influence aboveground and belowground carbon storage across environmental gradients remains poorly understood. 2. We measured aboveground and belowground carbon stocks and the variation in whole-plant (above- and belowground) functional strategies at the community level in twelve ecosystem types across a broad savanna-forest-alpine elevational gradient of climate and land use on Mt. Kilimanjaro, Tanzania. Using Structural Equation Models, we disentangled the direct and land use mediated influences of climate on carbon storage from indirect influences mediated by variation in plant functional strategies. 3. We found strong coordination between above- and belowground functional traits at the whole community level, which corresponded with functional strategies related to two major trade-offs: a slow-conservation to fast-resource acquisition axis represented by a spectrum from high leaf dry matter content to high fine root nitrogen concentration; and a size-related woody to grassy community axis represented by a spectrum spanning high canopy height to high specific root length. The slow-fast and woody-grassy strategy axes were primarily driven by precipitation and land-use intensity, respectively. 4. Both functional strategies mediated the effects of climate on carbon storage. The slow-fast strategy axis was strongly and positively associated with aboveground carbon stocks. Meanwhile, the woody-grassy strategy axis was negatively associated with both aboveground carbon stocks and soil organic carbon stocks. 5. Synthesis. We demonstrated that major plant functional strategies manifest at the community level along elevational gradients. These strategies also explain variation in carbon storage, although aboveground storage is mostly driven by trait effects, and belowground storage by direct effects of climate. Together, these results underscore the importance of incorporating functional community data into future analysis of climate change impacts on carbon storage, which would enhance our ability to predict potential shifts in ecosystem functioning.

ecology↗