Temporal shifts in the functional composition of Andean forests at different elevations are driven by climate change.
Creators: name: Martinez Villa, Johanna
name: Duran, Sandra M
name: Enquist, Brian
name: Duque, Alvaro
name: Messier, Christian
name: Paquette, Alain
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 310308
subject: Terrestrial ecology
classificationCode: 310302
subject: Community ecology (excl. invasive species ecology)

description: This file has the data and R code used to run the analysis in the article "Temporal shifts in the functional composition of Andean forests at different elevations are driven by climate change" in the Global Ecology and Biogeography (GEB) journal.*Changes in trait moments and drivers.R: R code to run the linear mixed models to assess changes in moments between census, trait velocity (TV) calculation, and the relationship between TV and potential drivers of functional changes (climate change and demographic changes). This code use the CVS files": "moments_LastCensus.csv", "moments_InitialCensus.csv", "WarmingRate_plots.xlsx", "WarmingRate_plots.xlsx".*Kormogolov-Smirnoff test.R: R code to run the Kormogolov-Smirnoff test (ks) between the trait distribution of the first and last census per trait and plot. This code uses the CSV file: "traits_taxo_census.cxv"*moments vs climate PC1 and PC2.R: R code to download climatic data from WorldClime 2 and perform a PCA. Linear models between the main PC axes from the PCA and the community moments by trait and plot. This code uses the files: "coordinates.csv", "moments_LastCensus" and "Climatic_variables_plots".<b>Abstract</b><b>Aim:</b> Andean forests are a global biodiversity hotspot. They harbor many species living within narrow climate ranges and a high functional diversity of trees. It is still unclear how such hotspots respond to climatic changes over time. We investigated whether Andean forests are changing their functional composition over time along an elevational gradient by assessing changes in species composition, abundance, and functional traits.<b>Location:</b> An elevational gradient in Colombia’s northern Andes.<b>Time period:</b> Species composition changes were studied 2 to 4 times from 2006 to 2017, and functional composition from 2016-2017<b>Major taxa studied</b>: 1,104 tropical tree species with <i>in situ</i> traits characterization.<b>Methods</b>: We used seven morphological leaf traits and wood density values to analyze the functional trait dynamic over ten years along an elevational gradient. By analyzing changes in species composition, abundance, and trait representation, we inferred the magnitude and direction of changes in functional composition. Then, we assessed if the functional change was related to climate change and demography.<b>Results: </b>With increased minimum temperature and vapor-pressure deficit, we found a decrease over time in mean values for leaf area and specific leaf area and increases in leaf thickness and leaf dry matter content. Long-term temperature increases are smaller with increasing elevation, but the magnitude of trait changes is greater than in lowlands.<b>Main conclusions:</b> The functional composition is changing towards more conservative strategies over time across the elevation gradient, with the strongest changes observed at the highest elevations. This pattern is explained by the change in species turnover within communities due to higher recruitment rates of species with high leaf dry matter content values and low leaf area values. These shifts may be related to communities’ responses to higher evapotranspiration demand and thermal stress, mainly at higher elevations.<br>