DOI: 10.5061/dryad.kk914
title: Data from: Potential trajectories of old-growth Neotropical forest functional composition under climate change

description: Quantifying relationships between plant functional traits and abiotic
 gradients is valuable for evaluating potential responses of forest
 communities to climate change. However, the trajectories of change
 expected to occur in tropical forest functional characteristics as a
 function of future climate variation are largely unknown. We modeled
 community level trait values of Costa Rican rain forests as a function of
 current and future climate, and quantified potential changes in functional
 composition. We calculated per-plot community weighted mean (CWM) trait
 values for leaf area (LA), specific leaf area (SLA), leaf dry matter
 content (LDMC), leaf nitrogen (N) and phosphorus (P) content, and wood
 basic specific gravity (WSG), for tree and palm species in 127 0.25 ha
 plots. We modeled the response of CWM traits to current temperature and
 precipitation gradients using generalized additive modeling. We then
 predicted and mapped CWM traits values under current and future climate,
 and quantified potential changes under a global warming scenario (RCP8.5,
 year 2050). We calculated the area within the multi trait functional space
 occupied by forest plots under both current and future climate, and
 determined potential changes in functional space occupied by forest plots.
 Overall, precipitation predicted CWM traits better than temperature.
 Models indicated increases in CWM SLA, N and P, and a decrease in CWM LDMC
 under climate change. Lowland forest communities converged on a single
 direction of change towards more acquisitive CWM trait values, indicating
 a change in forest functional composition resulting from a changed
 climate. Functional space occupied by forest plots was reduced by 50%
 under the future climate. Functional composition changes may have further
 effects on forests ecosystem services. Assessing functional trait
 spatial-gradients can help bridge the gap between species-based
 biogeography and biogeochemical approaches to strengthen biodiversity and
 ecosystem services conservation efforts. 
description: observed CWM
 traitsThis file contains the
 community weighted mean values (CWM) of six functional traits for 127
 old-growth forest plots in northeastern Costa Rica. CWM traits were
 calculated using relative abundance values of dominant tree (≥30 cm dbh)
 and palm (≥10 cm dbh) species registered in 0.25 ha plots (see Sesnie et
 al. 2009) and six species level foliar and stem traits, as follow: leaf
 area (LA, mm2), specific leaf area (SLA; mm2 mg-1), leaf dry matter
 content (LDMC, mg g-1), nitrogen foliar content (N, mg m-1), phosphorous
 foliar content (P, mg g-1), wood specific gravity (g
 cm3-1).predicted CWM traits
 currentThis file contains the
 CWM trait values predicted from models of response to current climate
 (1950–2000 period from wordlclim ) using
 generalized additive mixed models.predicted CWM year
 2050This file contains the
 CWM trait values predicted from models of response to future climate (year
 2050, RCP8.5, wordlclim ) using generalized
 additive mixed models.