Shifts in trait diversity, but not ecological strategies, across the range of an endemic treeline species in central Chile

Background and AimsClimate change is currently altering biodiversity by shifting species’ ranges. Yet, the mechanisms underlying these shifts are not well understood for plants, whose responses to changes in precipitation or temperature are often idiosyncratic. Here, we evaluated if ecological strategies mediate a key demographic process - growth - and whether intraspecific trait diversity shifts across the range of an endemic, treeline species in a region experiencing an extreme drought.MethodsWe measured functional traits of 45 individuals of Kageneckia angustifolia from populations at the center and trailing and leading edges of its distribution in central Chile. We identified individual-level ecological strategies using leaf and xylem traits and tested their association with tree growth, and estimated statistical moments of intraspecific trait variation and multidimensional trait diversity across populations.Data description The file contains leaf and xylem trait and tree growth data for individuals of Kageneckia angustifolia. Study site: This refers to the location of the sampled population (North (trailing edge; -30.99°S, -70.64°W), Center (central; -33.82°S, -70.12°W),South (leading edge; -35.05°S, -70.52°W)).Individual: This is a numeric identifier that refers to unique trees within each study site. Organ: This is a categorical variable that refers to the tree organ for which individual traits were measured, i.e. leaf or xylem. For tree growth, the corresponding value is "All", to differentiate it from the leaf and xylem traits. Trait: This is a categorical variable indicating the measured trait and includes the following traits, including their units:Tree_growth (μm yr-1): Tree growth is calculated as the mean of tree ring widths during the study period (2016-2020). L_Thickness (mm): Leaf thickness is the average thickness of the lamina, measured at three places.Leaf_Area (cm2): Leaf area is the area of the lamina.Perim_Area (cm2/cm2): Perimeter2:area is the ratio of the leaf perimeter to the leaf area. SLA(cm2/g): Specific Leaf Area is the ratio of leaf area to leaf dry mass. Stomatal_dens (#/mm2): Stomatal density is the number of stomata per area. Hd (µm): Hydraulic diameter was calculated following Sperry et al. (1994).Kp (kg m Mpa-1 s-1): Potential specific stem conductivity was calculated as the product of viscosity/density of H20, vessel frequency, and the hydraulic diameter.Vessel frequency (#/mm2): Vessel frequency is the number of vessels per area.Vulnerability index: The vulnerability index is the risk of the hydraulic failure due to vessel characteristics, and is calculated as the ratio of mean vessel diameter to vessel frequency.