Abstract: Spatial pattern of aboveground biomass of grassland community reflects spatial heterogeneity of resource allocation caused by terrain difference. Community survey method and generalized additive model (GAM) were used to study the response characteristics of community’s aboveground biomass spatial pattern at hill and hillslope scales in natural grassland of the northern slope of Qilian Mountains. The results showed that at the hill scale, terrain factors had definite effects on the aboveground biomass of community, with the sequence of elevation > slope of aspect (SOA) ≈ slope of slope (SOS) ≈ slope. When reducing hill scale to hillslope scale by aspect, the aboveground biomass of grassland community would be most affected by SOA in east and west aspects, and by elevation and SOS in south and north aspects. On east slope, community’s aboveground biomass firstly decreased then increased in SOA gradient, and vice versa in west slope. On south slope, it increased with elevation. On north slope, it firstly kept stable then decreased in SOS gradient. Our study suggested that the spatial pattern of aboveground biomass of grassland community was obviously scaledependent at hill and hillslope scales.

Key words: precipitation exclusion, warming, denitrification potential., N₂O flux, subtropics