Dieback intensity but not functional and taxonomic diversity indices predict forest productivity in different management conditions: Evidence from a semi-arid oak forest ecosystem

The relationships between different aspects of diversity(taxonomic,structural and functional)and the aboveground biomass(AGB)as a major component of global carbon balance have been studied extensively but rarely under the simultaneous influence of forest dieback and management.In this study,we investigate the relationships between taxonomic,functional and structural diversity of woody species(trees and shrubs)and AGB along a gradient of dieback intensity(low,moderate,high and no dieback as control)under two contrasted management conditions(protection by central government vs.traditional management by natives)in a semi-arid oak(Quereus brantii Lindl.)forest ecosystem.AGB was estimated and taxonomic diversity,community weighted average(CWM)and functional divergence indices were produced.We found that the aerial biomass was significantly higher in the intensively used area(14.57(±1.60)t/hm^(2))than in the protected area(8.70(±1.05)t/hm^(2))due to persistence of some large trees but with decreasing values along the dieback intensity gradient in both areas.CWM of height(H),leaf nitrogen content(LNC)and leaf dry matter content(LDMC)were also higher in the traditional managed area than in the protected area.In contrast,in the protected area,the woody species diversity was higher and the inter-specific competition was more intense,explaining a reduced H,biomass and LDMC.Contrary to the results of CWM,none of the functional diversity traits(FDvar)was affected by dieback intensity and only FDvar values of LNC,leaf phosphorus content(LPC)and LDMC were influenced by management.We also found significantly positive linear relationships of AGB with CWM and FDvar indices in the protected area,and with taxonomic and structural diversity indices in the traditional managed area.These results emphasize that along a dieback intensity gradient,the leaf functional traits are efficient predictors in estimating the AGB in protected forests,while taxonomic and structural indices provide better results in forests under a high human pressure.Finally,species identity of the dominant species(i.e.,Brant’s oak)proves to be the main driver of AGB,supporting the selection effect hypothesis.

Henriksen and Flora （1999） Revisited A Literature Review on Third-Person Effects and Children/Adolescents＊

In this literature review on TPE （third-person effects） and the behavioral consequences on children, the research questions posed are how the body of knowledge has evolved since the first empirical evidence of TPE among children and what knowledge gaps that remain. The traceable developments are two： （1） Compared to the vast amount of articles on TPE in general, the 5 9 identified on the topic of children are few and two thirds actually focus on adolescents/young adults rather than children. The reason put forward for studying younger children is the urge to prevent risky behavior through media literacy programs or pro-social advertisements; and （2） The studies have not primarily addressed results to support occurrence of TPE among children. Rather they support parental TPE or among the adolescents that TPE and reverse TPE occur due to certain kind of media content. The discussion on knowledge gaps that remain follow three themes： （1） Differentiations between self and others are in psychological studies implied to occur among children between the ages of 3-4 years old, yet no study address how children develop TPE; （2） There is a tendency to follow the more general development within TPE research with the renewed interest in behavioral consequences. But the primary behavioral consequence studied in TPE in general and within studies of TPE and children is support for censorship. Few studies address ＂real＂ behavioral consequences like parental mediation; and （3） There is also a need for more theoretically coherent research on the importance of social distance.