Spatial heterogeneity of soil respiration in a seasonal rainforest with complex terrain

Abstract

Although numerous studies have been conducted to investigate ecosystem-scale soil respiration, our understanding of this process is still incomplete, especially with respect to the spatial variability and ecological factors that drive such variability in respiration. The present study was conducted to investigate the respiration, structural parameters and soil properties in a seasonal rainforest with complex topography. Specifically, we sampled a 20-ha plot in intervals of 20 m to measure the soil respiration. Based on the entire 20-ha plot, the spatial mean soil respiration rate was 4.09 µmol m-2 s-1 and 2.71 µmol m-2 s-1 during the rainy and dry season, respectively. Strong spatial heterogeneity was observed, with coefficients of variance of 42% and 38% being obtained for the rainy and dry season, respectively. The patch size of soil respiration was approximately 40 m, which was much smaller than that of the soil temperature and water content. Soil-respiration hot spots induced a right-skewed probability density function of soil respiration in space. However, termite mounds did not account for the respiration hot spots. The required number of sampling points in our studied forest was estimated to be 71 and 51 for the rainy and dry season, respectively.

Keywords

• Semivariance
• Soil Physical and Chemical Properties
• Soil-respiration Hot Spots
• Stand Structure