DOI: 10.5061/dryad.k3j9kd54c
title: Data from: Climate synchronises shrub growth across a high-arctic archipelago: contrasting implications of summer and winter warming

description: Climate change is most pronounced at high latitudes, where plant and
 animal populations are often strongly influenced by environmental
 fluctuations related to climate and weather. Environmental conditions can
 co-fluctuate over large distances and thereby synchronise primary
 production in space. However, large-scale studies of such spatiotemporal
 patterns remain rare in the Arctic, where short time-series and poor
 spatial replication have characterised the data available on both biotic
 and abiotic parameters. Here, we use dendrochronological tools to measure
 ring growth of a dominant dwarf shrub, the polar willow (Salix polaris
 Wahlenb.), previously found to reliably trace community-level vascular
 plant biomass production. We investigated climate drivers of vegetation
 growth and their role in the synchronisation of primary production across
 the rapidly warming archipelago of Svalbard (n = 8 sites, composed of 17
 sub-sites, 0.06-293 km apart). We found contrasting effects of summer
 versus winter weather on ring growth and its spatial synchrony. Although
 an overall positive effect of summer temperature caused spatially
 synchronous growth, negative impacts of winter rain-on-snow events
 occurred only locally, potentially counteracting such synchrony. However,
 the anticipated increase in both summer temperature and spatial extent of
 rain-on-snow events, causing basal ice encapsulation of the vegetation,
 could change the relative importance of seasons for spatiotemporal
 dynamics of shrub growth. Because these shrub ring growth chronologies
 reflect annual fluctuations in total vascular plant biomass, fuelling the
 bottom-up controlled food-web, these results have large implications for
 our understanding of how climate change shapes tundra ecosystem
 productivity in time and space.
description: See the method section of the corresponding article doi:10.1111/oik.07059
description: Please read the ReadMe file before to download the
 data.  A R script is available on request:
 mathilde.lemoullec@ntnu.no.  File description for
 manuscript Le Moullec et al. 2020 Oikos: doi: 10.1111/oik.07059
 # 1. Files to build chronologies .rwl -
 rwl_petuniabukta.rwl   # rwl file from Salix polaris chronologies (at the
 plant level) published in Buchwal et al. 2013. Polar Biol.<br> -
 rwl_Semmeldalen.rwl  # rwl file from Salix polaris chronologies (at the
 cross-section level) published in Le Moullec et al. 2019 JEcol<br> -
 rwl_svalbard_new.rwl  # rwl from 6 new sites, 30 Salix polaris individual
 chronologies (at the cross-section level) <br> - plant_info.txt    
           # Cross section's radius and ring to pith information of
 file "rwl_svalbard_new.rwl", for possible standardization e.g.
 BAI, RCS # 2. Ring-growth information at the plant
 level formatted for linear mixed-effect models or synchrony
 analysis. <br> - Salix_ind_BAIrcs_RAWpetunia_MeanCenter # Individual
 shrubs' RWI (standardized = BAI + RCS + Mean Centered).              
                                                                          
                                                                           
 # NOTE that ring growth from Petuniabukta are ONLY Mean Centered
 - Salix_ind_RAW # Individual shrubs' raw ring width
 (micrometers) # 3. Climate data <br> -
 climat_raw_Oikos         # Raw climate data for each station used across
 Svalbard, provided by eKlima.no (except Hornsund).                        
                                                                          
                      # Hornsund: data provided by the Institute of
 Geophysics Polish Academy of Sciences and meteorological staff of the
 Polish Polar Station Hornsund <br> - climat_estimated_Oikos # Each
 climate variable is an estimate at the Svalbard scale: from a linear
 mixed-effect models with (1|Station) as random effect<br> -
 climat_estimated.se_Oikos # Standard error of the climate estimates
 "climat_estimated_Oikos" # 4. GPS coordinates
 for distance matrix<br> - site_GPS     # Each Salix polaris'
 subsite UTM coordinates