DOI: 10.5061/dryad.q28h6
title: Data from: Multiple environmental drivers structure plant traits at the community level in a pyrogenic ecosystem

description: Trait-based approaches offer a way to predict changes in community
 structure along environmental gradients using measurable properties of
 individuals. Promoted as being generalizable across systems, trait-based
 approaches benefit from information about the environmental drivers of
 trait variation, how they interact and how they change with scale.
 However, for most diverse, natural communities, it is largely unknown
 whether the relationships between leaf-level traits and interacting
 environmental drivers (e.g. fire, water availability) are influenced by
 the scale of trait aggregation. We show that landscape-level differences
 in community composition in a diverse, fire-dependent pine savanna are
 explained by a small subset of species groups that are strongly correlated
 with soil moisture and elevation, but are insensitive to the time since
 the last fire. We used a trait-based approach to show that significant
 variation in the community-weighted mean (CWM) of specific leaf area (SLA)
 and leaf dry matter content (LDMC), two traits known to drive community
 structure and function, was explained by a small set of factors including
 the time since the last fire, soil moisture, precipitation and Shannon
 diversity. We show that statistical inference about the environmental
 drivers of community traits is radically altered when using CWMs computed
 with landscape-level rather than plot-level means, even over modest
 spatial scales. Synthesis: Environmental drivers of community composition
 across the landscape differed from those explaining trait composition. CWM
 traits were strongly influenced by interactions between drivers. Fire, in
 particular, strongly mediated the effect of other environmental variables
 on LDMC, showing that strong environmental gradients cannot be considered
 independently when assessing their effects on functional traits. The
 importance of environmental variables such as fire was lost when using
 landscape-level trait means, highlighting the importance of local trait
 variation. This suggests caution when using traits from distant
 populations to make inferences about local processes, especially across
 strong gradients.
description: Ordination
 DataThis file contains the
 data used in the ordination portion of our analysis. “Site_Plot” lists the
 site and plot identifier where the data were collected. “Date” gives the
 date that the cover measurements were collected. The remaining columns
 give the cover measurements for each species, with the names corresponding
 to the species list in the supplementary material. For example, ACERUB is
 Acer rubrum. The cover measurement is the sum over the four subplots, so
 the values may range from 0-400%.AmesetalOrdinationData.csvCommunity Weighted Mean Trait DataThis file contains the data used the community weighted mean trait analyses, with the exception of climate data which was obtained from DAYMET (Thornton et al. 2012). The “Site_Plot” column lists the site and plot identifier where the data were collected. “Date” gives the date that the trait measurements were collected. “Elevation” is the height (cm) of the center of the plot above the nearest stream. “Bulk Density” is the plot soil bulk density (g/cm3). “Days Since Burn” is the number of days since the last fire. “Shannon Index” gives the Shannon Diversity Index, H. The remaining columns give the community weighted mean SLA (g/cm3) and LDMC (%) based on the landscape level species trait averages and the plot level species values.AmesetalCWMdata.csv