Plant Functional Types and Their Impact Environmental Factors in aNaturally Recovered Poplar - birch Woodland on the North Slope ofQilian Mountains, China

Abstract

Plant functional types(PFTs) are important in understanding the dynamics and the functions of an ecosystems,which provide also useful information for ecosystem management.In 28 observation plots of a naturally recovered poplarbirch woodland on the north slope of Qilian Mountains,China,81 plant species were classified into 18 plant functional types(PFTs),according to their life forms(including arbors,lianas,subshrub,shrub,perennial grasses,perennial forbs and annual or biennial grass) and ecotypes(including xerophyte,xerophytic and mesophytic,mesophyte and hygrophyte).The relationships between PFTs and environmental factors were studied using Canonical Correspondence Analysis(CCA).The results showed that the dominant PFTs were PFTs16(mesophytic perennial forbs),PFTs23(hygrophytic perennial forbs),PFTs9(xerophytic and mesophytic perennial forbs) and PFTs18(mesophytic shrub) on the poplar-birch restoration woodland.The stratified structure with wood,shrub and herb layers indicated the plant life forms had a tendency of complication and structurization,and the emerging mesophyte plants reflected changes of the micro-environments.The distribution patterns of PFTs were controlled by the soil physical and chemical properties in that soil bulk density,soil organic carbon and content of nitrogen determined the characteristics of the plant life forms,while the soil water moisture and canopy cover were the main ecological factors that affected the distribution of ecotypes.The slope position and slope aspect controlled the plant distribution pattern and formation of the community.Fig 1,Tab 3,Ref 31