Data from: Plant diversity in giant panda habitat

Understanding the relative importance of the factors driving the patterns
of biodi- versity is a key research topic in community ecology and
biogeography. However, the  main drivers of plant species
diversity in montane forests are still not clear. In addi- tion, most
existing studies make no distinction between direct and indirect effects
of  environmental factors and spatial constraints on plant
biodiversity. Using data from  107 montane forest plots in
Sichuan Giant Panda habitat, China, we quantified the  direct and
indirect effects of abiotic environmental factors, spatial constraints,
and  plant functional traits on plant community diversity. Our
results showed significant  correlations between abiotic
environmental factors and trees (r = .10, p value = .001), 
shrubs (r = .19, p value = .001), or overall plant diversity (r = .18, p
value = .001) in mon- tane forests. Spatial constraints also showed
significant correlations with trees and  shrubs. However, no
significant correlations were found between functional traits 
and plant community diversity. Moreover, the diversity (richness and
abundance) of  shrubs, trees, and plant communities was directly
affected by precipitation, latitude,  and altitude. Mean annual
temperature (MAT) had no direct effect on the richness of  tree
and plant communities. Further, MAT and precipitation indirectly affected
plant  communities  via  the  tree
 canopy.  The  results  revealed
 a  stronger  direct  effect
 on  montane plant diversity than indirect effect,
suggesting that single-species models  may be adequate for
forecasting the impacts of climate factors in these communities. 
The shifting of tree canopy coverage might be a potential indicator for
trends of plant  diversity under climate change.