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 (Quercus 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/hm2) than in the protected area (8.70 (±1.05) t/hm2) 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.

Mona KARAMI;Mehdi HEYDARI;Ali SHEYKHOLESLAMI;Majid ESHAGH NIMVARI;Reza OMIDIPOUR;YUAN Zuoqiang;Bernard PREVOSTO

Faculty of Natural Resources,Chalus Branch,Islamic Azad University,Chalus 46615/397,Iran;Department of Forestry,Chalous Branch,Islamic Azad University,Chalous 46615/397,Iran;Department of Rangeland and Watershed Management,Faculty of Natural Resources and Earth Sciences,Shahrekord University,Shahrekord 8818634141,Iran;Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110164,China;INRAE,Aix Marseille University,UMR RECOVER,Mediterranean Ecosystems and Risks,Aix-en-Provence 13128,France

干旱区科学

[1]Mona KARAMI;Mehdi HEYDARI;Ali SHEYKHOLESLAMI;Majid ESHAGH NIMVARI;Reza OMIDIPOUR;YUAN Zuoqiang;Bernard PREVOSTO-.Dieback intensity but not functional and taxonomic diversity indices predict forest productivity in different management conditions: Evidence from a semi-arid oak forest ecosystem)[J].干旱区科学,2022(02):225-244

Dieback,dieback,brantii,FDvar

intensity,but,not,functional,taxonomic,diversity,indices,productivity,different,management,conditions,Evidence,from,semi,arid,oak,ecosystem,relationships,between,aspects,structural,aboveground,biomass,AGB,major,component,global,carbon,balance,have,been,studied,extensively,rarely,under,simultaneous,In,this,study,investigate,woody,species,trees,shrubs,along,gradient,low,moderate,control,two,contrasted,protection,by,central,government,traditional,natives,Quercus,Lindl,was,estimated,community,weighted,average,CWM,divergence,were,produced,We,found,that,aerial,significantly,higher,intensively,used,hm2,than,protected,due,persistence,some,large,decreasing,values,both,areas,height,leaf,nitrogen,content,LNC,dry,matter,LDMC,also,managed,inter,specific,competition,more,intense,explaining,reduced,Contrary,results,none,traits,affected,only,phosphorus,LPC,influenced,positive,linear,These,emphasize,efficient,predictors,estimating,forests,while,provide,better,human,pressure,Finally,identity,dominant,Brant,proves,main,driver,supporting,selection,effect,hypothesis

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