Abstract
Although trait choice is crucial to quantify functional diversity appropriately, the quantitative methods for it are rarely compared and discussed. Meanwhile, very little is known about how trait choice affects ecological conclusions drawn from functional diversity measures. We presented the four methods of trait selection as alternatives to the ordination axis-based method, which directly identify a subset of key traits to represent the main variation of all the traits. To evaluate their performance, we compared the closeness of association obtained by different methods between species richness and functional diversity indices (FAD, FD, Q, FDis) in the six ecosystems. The evaluation was also benchmarked against the results obtained by calculating the possible indices using all the trait combinations (the complete search method). We found that the trait selection methods were potential alternatives to axis-based method to gain a mechanistic understanding of functional responses and effects of traits, while these methods as well as the axis-based method possibly use mismatched information to interpret the investigated ecosystem properties. Trait choice profoundly affected the ecological conclusions drawn from functional diversity measures. The complete search method should be used to assess the rationale of different trait choice methods and the quality of the calculated indices.
Highlights
Functional diversity is increasingly recognized as an important approach for understanding the mechanisms of species coexistence or community assembly[1,2,3], and characterizing the functional responses and effects of biological communities[4,5,6,7,8]
The recent researches suggest that some conceptual and methodological pitfalls are present with the ordination axis-based method[18], which urge us to propose the four methods of choosing traits directly from a set of traits based on the Principal Component Analysis (PCA), and these traits can be used to calculate functional diversity
We find that the traits previously considered to be important dimensions for plant ecological strategies are not always present in the best trait combinations that capture the main variations of all the traits or best interpret the variation of species richness (Tables 1 and 2)
Summary
Functional diversity is increasingly recognized as an important approach for understanding the mechanisms of species coexistence or community assembly[1,2,3], and characterizing the functional responses and effects of biological communities[4,5,6,7,8]. Petchey et al.[22] propose that all the possible functional diversity indices should be calculated with every combination of traits, and we can find the most suitable one that can be used to interpret ecosystem properties. This approach represents a pragmatic method to weight the traits by zero or one in all the trait combinations. We calculated all the possible functional diversity indices using different numbers and identities of traits, and we establish all the possible association between all these indices and ecosystem property We call this method as the complete search. The comparison among the complete search, axis-based and trait selection methods would assess the effects of trait choice on the ecological conclusions
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call