Poster Session: Cross-Scale Landscape Analysis

Scaling up soil respiration from plots to the region: A case study in Inner Mongolia. Zhang, Jian^*,1, Wu, Jianguo ¹, Chen, Quansheng², Li, Linhao², Bai, Yongfei², ¹ Landscape Ecology and Modeling Laboratory (LEML), Tempe, AZ, USA² Institute of Botany, Beijing, Hebai, China

ABSTRACT- Landscape-scale estimation of soil respiration is important to understanding carbon source and sink relations on the regional and global scales. Because no method can directly measure soil carbon efflux over a large region, it is necessary to develop scaling-up methods. Inner Mongolia Grassland, a part of the vast Eurasian Steppe Region running from eastern China to Hungary, is a prominent ecosystem in the world. Several plot-level studies of soil respiration recently were carried out in the Inner Mongolia Grassland, China, providing an excellent opportunity for developing and testing scaling approaches. The objectives of this research were: (1) to estimate regional-scale soil respiration based on plot-level measurements using different scaling methods, (2) to quantify the spatial heterogeneity of soil respiration using spatial statistical methods, and (3) to compare and contrast different scaling methods based on the landscape pattern of soil respiration and other related ecological variables. Three scaling methods were used: simple lumping, extrapolation by vegetation types, and extrapolation by biomass (derived from remote sensing data). Our results showed that the three methods produced different results. While the simple lumping method is generally not to be trusted when the landscape under study is highly heterogeneous, vegetation types-based estimates may have underestimated soil respiration due to vegetation classification errors. Extrapolation by biomass seemed to be a promising method in this case. We have further examined how spatial pattern of vegetation and environmental factors (temperature and moisture) may affect the scaling up of soil respiration from plots to the region.

KEY WORDS: soil respiration, spatial scaling, carbon budget, landscape pattern of soil respiration, spatial extrapolation