Effects of soil and microclimatic conditions on the community-level plant functional traits across different tropical forest types

Variations in community-level plant functional traits might indicate the adaptation strategies of vegetations under changing environment. Here, we assess the key factors in controlling functional community compositions across different forest types. We established 12 1-ha permanent forest dynamics sites, two in each of the six old-growth forests. Each site was divided into 25 plots (20 m x 20 m). We measured five plant traits and eight abiotic factors in each plot. Correlations between environmental factors and plant traits were assessed by step-wise multiple regression. The key abiotic factors controlling community-level plant functional traits in TDMRF were CO, SWC and AN. Those in TCF were CO and AN, in TLRF was AP, in TMRF were CO and TP, in TMEF were pH, SOM and TP, and in TMDF were SWC, pH, TN and TP, respectively. The controlling factors for each of the trait across the vegetations were: SWC, pH,TN,TP and AN for CWM_SLA; CO and AN for CWM_CC;CO, pH, SOM,TN and AN for CWM_LNC;CO,pH,TN and TP for CWM_LPC;and CO,SWC,TN, AN and AP for CWM_WD. Key soil and microclimatic factors controlling plant functional traits change with vegetation types. Each community-level plant functional trait is associated with 3-5 abiotic factors across the vegetations.