DOI: 10.5061/dryad.rfj6q57c1
title: Do tradeoffs govern plant species responses to different global change treatments?

description: Plants are subject to tradeoffs among growth strategies such that
 adaptations for optimal growth in one condition can preclude optimal
 growth in another. Thus, we hypothesized that the response of plant
 species abundance to one global change treatment would relate inversely to
 the response to a second treatment, particularly for treatment
 combinations that accentuate distinct traits. To address this hypothesis,
 we examined plant species abundances in 39 global change experiments
 manipulating CO2, nitrogen, phosphorus, water, temperature, or
 disturbance. Overall, the directional response of a species to one
 treatment was 13% more likely than expected to oppose its response to a
 second. This tendency was detectable across the global dataset but held
 little predictive power for individual treatment combinations or within
 individual experiments. While tradeoffs in the ability to respond to
 different global change drivers exert detectable effects globally, other
 forces may obscure their influence in local communities.
description: We analyzed the CoRRE database (Komatsu et al. 2019;
 corredata.weebly.com), which compiles species abundance information from
 herbaceous plant communities subjected to experimental manipulations
 mimicking global change drivers. We included studies from the database
 that manipulated at least two global change drivers (elevated CO2,
 nitrogen addition, phosphorus addition, multiple nutrient addition, water
 addition, droought, warming, and disturbance, where disturbance included
 burning, mowing, or clipping) for at least three years. For each of these
 experiments, we estimated each species' mean abundance across all
 years in the control plots and in each relevant treatment plot (single
 factor manipulations only). We calculated three different effect size
 metrics using species mean abundance in treatment plots (t) and control
 plots (c): 1) E=(t-c)/(t+c), 2) LRR=ln(t/c), 3) PS=(t-c)/c. We also
 include data on species mean abundance in the control plots. We coded data
 to indicate whether species were present in at least one treatment plot
 and one control plot (present), or if they were absent from either all
 treatment or all control plots. We also include in this
 dataset the results of 999 runs of a null model where we randomly
 reshuffled the treatment assignments among all control and all treatment
 plots within each experiment. We then calculated species mean abundances
 and effect sizes as above for the observed data.
description: "Permutation" column indicates a number (1-999) if the
 community data were simulated or "real" if the data were
 observed in the global change experiments in the field. The
 "site_project_comm" column gives an identifier for the
 experiment; see the manuscript supplement for more details on the sites
 and experiments. The "species" column gives the species name or
 code provided by the data collectors. The
 "global.change.treatment" column indicates which of the
 following types of manipulation was imposed upon the treatment
 plots: elevated CO2 ("CO2"), nitrogen addition
 ("N"), phosphorus addition ("P"), multiple nutrient
 addition ("mult_nutrient"), water addition ("irr"),
 drought ("drought"), warming ("temp"), and disturbance
 ("BMCT"). Species that were absent in either all treatment plots
 (coded "absent treatment" in the "code" column) or all
 control plots ("absent control") have NA for log response ratio
 (column "LRR") because this value is incalculable in either
 situation. Species absent in all control plots have NA for percent
 stimulation (column "PS") because this value is incalculable in
 that situaiton. All species have a value between -1 and 1 in the
 "E" column. Species mean abundance in control plots
 ("relabund.control" column) is given only for the
 "real" data and is NA whenever permutation is a number 1-999 or
 when a species was absent from all replicate control plots (code is
 "absent control").