DOI: 10.5061/dryad.zkh1893hw
title: Vegetation changes with climate change in the Grandes Rousses mountain range

description: Questions: We assessed interactions between climate change, bedrock types
 and snow cover duration on the trajectories of taxonomic and functional
 composition of subalpine plant communities. We predict (i) an increase in
 species richness on siliceous bedrock due to a reduced competition and a
 decrease in richness on calcareous bedrock due to increasing drought
 stress, (ii) decreasing snow cover duration should induce a higher shrub
 encroachment in hollows as compared to ridges (iii) increasing growing
 season temperature should induce taller sizes and more conservative growth
 traits, in particular in hollows. Location: Subalpine belt of the Grandes
 Rousses mountain range, south western Alps (France). Methods: 189
 vegetation plots were sampled in 1997 and 2017-2018. The duration of snow
 cover was assessed during two years in 1995-1997 and five functional
 traits were measured on 108 species in 2021. We performed multivariate
 analyses, quantified community weighted-means (CWM) of traits and used
 ANOVAs to detect responses to local-scale factors and changes in snow
 cover, temperature and precipitation since 1997 according to a nearby
 meteorological station. Results: Overall, taxonomic composition weakly
 changed and changes were more dependent on the position of communities
 along the snow cover duration gradient than on their bedrock type. The
 abundance of drought-tolerant species increased at the border of hollows
 and there was, over all communities, a slight increase in the abundance of
 dwarf shrubs and tall herbaceous species, a strong decrease in short
 herbaceous species and, thus, an overall decrease in species richness.
 There were important overall changes in CWM of size traits, in particular
 leaf area which increased the most in hollows irrespective of bedrock
 types. Conclusion: In this subalpine site the effects of decreasing snow
 cover duration overwhelmed the effects of bedrocks, which may explain the
 overall increase in competitive species and decrease in species richness.
description: 189 vegetation quadrats were done in 1997 and 2018.
 We measured plant traits and calculated CWM of traits at the two
 years of sampling.
description: # Vegetation changes with climate change in the Grandes Rousses mountain
 range **Principal investigator (or person responsible for collecting the
 data):** Richard Michalet, University of Bordeaux, France,
 [richard.michalet@u-bordeaux.fr](mailto:richard.michalet@u-bordeaux.fr)
 **Date of data collection:** 1997, 2017, 2018 **Information about
 geographic location of data collection:** Isère department, France. **The
 file, created in 2024, includes 2 sheets :** 1.     Vegetation
 composition : Vegetation plots data (Fig. 2 & 3). 2.     Plant
 traits : CWM of plant traits (Fig. 4 & 5). **There are no restrictions
 on the data.** **Description of methods for data collection or
 generation**: Vegetation composition was sampled using quadrat sampling
 (Michalet et al. 2002, Arctic, Antarctic & Alpine Research). Plant
 traits measurements and CWM calculation are done following Michalet et al.
 (2023, Ecology). **Description of methods used for data processing:** We
 used CA for vegetation composition and PCA for plant traits, both followed
 by ANOVAs. **Variable list, units of measurement**: **Sheet 1 (vegetation
 composition):** N° (information): plot number. Year (effect variable):
 year of sampling. All other columns (species names): Species counts.
 **Sheet 2 (plant traits):** Species (information): species names. Height:
 extended height (cm). Width: lateral extension (cm). LDMC: Leaf Dry Mass
 content (percentage). SLA: Specific Leaf Area (cm2.g-1). LA: Leaf Area
 (cm2). **Definitions for codes or symbols used to record missing data:**
 n/a.