The Relationship Between Plant Functional Diversity Of Typical Forests And Productivity In Eastern China

Plant trait diversity is a comprehensive indicator being used to describe the distribution range and degree of plant traits in the community,which can reflect the overall differences in plant community traits.We measured 34 traits of 366 species in 9 typical forests along the north-south in eastern China(From Huzhong,Heilongjiang province to Jianfengling,Hainan Province),including leaf structure traits,stomatal traits,anatomical structure traits,element traits,chlorophyll traits,etc.,and analyzed diversity indices of various functional diversity.The variation of large-scale functional diversity and its relationship with GPP were studied.At the same time,the relationship between the number of traits and the functional diversity was studied by using the characteristic indices measured systematically and the designed algorithm.In addition,in the small-scale case analysis,using the experimental forest area of jiaohe City,Jilin Province as the research platform and using the method of space instead of time,selected a gradient of seven forests with different restoration duration after selective cutting(from 6 to >100 years)to investigate these plant traits.We studied the change rules of three indices.(1)The functional indices of richness(FRic),evenness(FEve),and divergence(FDiv)differed significantly across forests.Furthermore,FEve showed a weak change with latitudinal increased.FRic decreased with temperature and precipitation;the opposite results were obtained for FDiv.Functional trait diversity,climate,and soil combined explained 90.4% of the total variation in GPP from cold-temperate to tropical forests.The results confirmed that there is spatial variation in functional trait diversity;moreover,functional trait diversity is important for determining spatial variation in GPP in large-scale natural forests and should be integrated in ecological models.(2)Functional richness increased with the number of traits,whereas the relationships between trait divergence indices and number of traits were inconsistent.Four of the seven functional diversity indices (FAD,MFAD,FRic,and Rao Q)were predictable or comparable with those in existing studies.With the change of the number of traits,they showed as different changing trends.Our results verified our hypothesis that the number of traits strongly influences functional diversity.The relationships between these predicted functional diversity metrics and the number of traits facilitated the development of a standard protocol.These findings can help to integrate data on functional diversity indices from different studies from the site to regional scale.and lead the future research on functional diversity.(3)with the increase of the restoring duration of selective cutting,FRic showed a decreasing trend first and then increasing.It was the lowest in the plots of 36-year restoration period,and the difference of FRic among different forest communities was significant.However,there is no significant difference in FEve among communities,and the effect of selective cutting on FEve is insignificant.FDiv showed a decreasing trend with the increase of the restoring duration after selective cutting,and which was greatest in the forests that recovered more than 100 years.From our results,the parameters of plant trait diversity did not alter as regularly in the restoration gradient of selective cutting,and unexpectedly,there is no apparent relationship between trait diversity and species diversity.Our findings inspired us that it is very difficult to single use trait diversity to explain the variation of ecosystem functioning,and the combination of trait diversity and species diversity should be a good substitution in future.From the relationship between the diversity of large-scale functional diversity and the productivity of ecosystem and the variation of functional diversity of restored by small-scale selective cutting,we can see that functional diversity combined with resource supply factors and species diversity can better interpret the adaptation and response of plants to the environment.In addition,in the methodology research,the research results of the effect of the selection of the number of traits on the functional diversity index can also provide scientific basis for integrating the existing research and guiding the future research.