Biology subjects

Scotti-Saintagne, C.

Publications and source records attributed to Scotti-Saintagne, C..

4 recordsLinked to original sources

bioRxiv2026

Multiscale intraspecific variation and coordination of hydraulic traits in silver fir

O_LIIntraspecific variability in hydraulic and morphological traits may alter projections of forest vulnerability to climate change. Recognizing multiscale nature is essential, as trait relationships within populations may not reflect those across the species range. C_LIO_LIWe assessed variability in 11 traits in 10 natural populations of Abies alba across environmental and phylogeographic gradients to evaluate potential impacts on drought vulnerability. We quantified trait variation within and among populations, tested effects of climate, phylogeny and local factors, and evaluated trait coordination across scales. C_LIO_LIHydraulic safety traits and wood density showed low variability, indicating strong constraints. In contrast, water-use and efficiency traits were highly variable. Aridity influenced several traits, but reduced variance was detected only for leaf residual conductance and succulence consisted with stabilising selection. Trait coordination was weak within populations than among populations. C_LIO_LIOverall, A. alba combines constrained hydraulic safety traits with variable water use traits. This may buffer drought impacts but limits shifts in hydraulic safety margins, potentially increasing risks of hydraulic failure, especially in humid environments where populations lack the capacity to tolerate prolonged dry periods. Thus, our findings highlight the need to account for scale-dependent trait variability, coordination, and their underlying drivers when predicting species adaptive capacity to drought. C_LI

plant biology↗

bioRxiv2025

Near-infrared spectroscopy-based models correctly classify Abies alba seed origin and predict germination properties

Forestry industry requires high-quantity and quality seeds for afforestation and assisted migration programs. Finding reliable non-destructive methods to characterize seeds would significantly enhance efforts to identify climate-adapted populations. This study presents near-infrared (NIR) spectroscopy models to classify seed origin and predict germination characteristics at different temperatures non-destructively. We focus on Abies alba Mill., a key European forest tree with genetic variation along climatic gradients and seeds with shallow physiological dormancy. Seeds from six populations were analyzed using NIR spectroscopy, and germination was tested at 15{degrees}C, 20{degrees}C, and 25{degrees}C after stratification treatments at 4{degrees}C (0 or 3 weeks). Population classification accuracy using Partial Least Squares Discriminant Analysis was 69%, with significant NIR peaks at 1712, 1929, and 2111 nm, linked to moisture content and storage compounds. NIR spectra explained 51% and 65% of the variation in germination probability and timing using Partial Least Squares Regression, with significant peaks at 1712, 1929, 2111, 1632, and 2073 nm. General Linear Mixed-Effects Models showed that a NIR predictor contributed to 39% of the germination probability variance explained by fixed-effects, and the stratification treatment was the most important driver explaining germination time. Our results proved the utility of NIR-based tools to effectively classify bulked seeds and predict germination, opening new perspectives to nursery and forestry sectors and populations adaptation and adjustments to warming climate. This study will facilitate further investigations on the physiological processes that occur during dormancy, a critical process for forest regeneration given the expected impact of shorter and warmer winters on seed behavior.

ecology↗

bioRxiv2025

Beyond Proxies: Towards ecophysiological indicators of drought resistance for forest management

As drought-induced mortality increases globally in forest biomes, it becomes necessary for foresters to have access to reliable predictors of species vulnerability to drought and mortality risk under different climatic scenarios. On the one hand, there exist several "operational" indicators of drought resistance, which are based on observations, expert knowledge and species bioclimate (e.g. Ellenberg, Rameau, ClimEssences). On the other hand, as traits can now be measured at high throughput, functional traits (such as plant hydraulic traits) have been increasingly used to assess species vulnerability to hydraulic failure, a key process of tree mortality under drought. However, this mechanistic approach has never been compared to the operational approach. In this study, we review if indicators commonly used by foresters provide information on Abies species vulnerability to hydraulic failure. We measured a set of traits in a common garden experiment of closely related Mediterranean Abies species. These traits were used as inputs to the SurEau model to compute a single indicator of vulnerability (Time to Hydraulic Failure - THF) and to assess mortality risk in future climate. We found that among circum-Mediterranean firs, a high THF was mainly due to high water losses after stomatal closure. Some operational indicators are good proxies of THF, however they are not available for all species, reduce a species to a single value and have the same limitations as species distribution models. We argue that the ecophysiological approach could help foresters in species selection and in estimating the risk faced by forest tree species in a changing climate. While accounting for the variability of traits, hydraulic models can be forced with different climatic scenarios allowing hydraulic failure risk assessment by the end of the century. HighlightsO_LIIntegrating ecophysiological traits in a process-based model allows the computation of an accurate indicator of vulnerability: the Time to Hydraulic Failure (THF). C_LIO_LIFor Abies species, "operational" indicators, i.e. indicators used by foresters and land managers, are mutually consistent and can be simplified proxies of the vulnerability to hydraulic failure. C_LIO_LIMore research on intra-specific variability is needed to assess the evolutionary potential of Euro-Mediterranean Abies species. C_LI

ecology↗

bioRxiv2019

The genetic structure of the European black pine (Pinus nigra Arnold) is shaped by its recent Holocene demographic history.

Fragmentation acting over geological times confers wide, biogeographical scale, genetic diversity patterns to species, through demographic and natural selection processes. To test the effects of historical fragmentation on the genetic diversity and differentiation of a major European forest tree and to resolve its demographic history, we describe and model its spatial genetic structure and gene genealogy. We then test which Pleistocene event, whether recent or ancient, could explain its widespread but patchy geographic distribution using population genetic data, environmental data and realistic demographic timed scenarios. The taxon of interest is a conifer forest tree, Pinus nigra (Arnold), the European black pine, whose populations are located in the mountains of southern Europe and North Africa, most frequently at mid-elevation. We used a set of different genetic markers, both neutral and potentially adaptive, and either bi-parentally or paternally inherited, and we sampled natural populations across the entire range of the species. We analysed the data using frequentist population genetic methods as well as Bayesian inference methods to calibrate realistic, demographic timed scenarios. Species with geographically fragmented distribution areas are expected to display strong among-population genetic differentiation and low within-population genetic diversity. Contrary to these expectations, we show that the current diversity of Pinus nigra and its weak genetic spatial structure are best explained as resulting from late Pleistocene or early Holocene fragmentation of one ancestral population into seven genetic lineages, which we found to be the main biogeographical contributors of the natural black pine forests of today. Gene flow among the different lineages is strong across forests and many current populations are admixed between lineages. We propose to modify the currently accepted international nomenclature made of five subspecies and name these seven lineages using regionally accepted subspecies-level names. HighlightsO_LIThe European black pine, Pinus nigra (Arnold), has a weak spatial genetic structure. C_LIO_LIGene flow among populations is frequent and populations are often of admixed origin. Current genealogies result from recent, late Pleistocene or Holocene events. C_LIO_LISeven modern genetic lineages emerged from divergence and demographic contractions. C_LIO_LIThese seven lineages warrant a revision of subspecies taxonomic nomenclature. C_LI

ecology↗