Characteristics of soil CO₂ efflux under an invasive species, Moso bamboo, in forests of central Taiwan

Key message: Soil respiration in a Moso bamboo forest was very sensitive to high temperatures, while ordinary annual soil respiration was comparable to that of other forests. Abstract: Moso bamboo (Phyllostachys pubescens) is expanding aggressively by replacing pre-existing vegetation in areas of East Asia such as Taiwan. Such changes in species composition in forest ecosystems have the potential to alter soil respiration (R_S) through changing soil carbon (C) processes. This study aimed to characterize the R_S in a Moso bamboo forest by determining temporal variations in R_S and estimated annual R_S in a pure Moso bamboo stand in central Taiwan. The annual R_S in the Moso bamboo stand was also compared with that in adjacent coniferous forests and reports in the literature relative to annual litterfall C. Although distinct diurnal variations in R_S were found on days with higher R_S and soil temperature (T_S), R_S measured at a single time between 7:00 and 14:00 h showed considerable concordance with the daily mean R_S. Seasonal R_S variation reflected variations in T_S with minimum values in winter and maximum values in summer. This seasonal dynamic change in R_S was predicted by the exponential function (r² = 0.57) with T_S. The Q₁₀ value derived from Moso bamboo forest was 4.09, substantially higher than that in the adjacent forests (Q₁₀ = 1.42–2.16) and the worldwide median (2.0–2.4). The estimated annual R_S rate (=1088.69 g C m⁻² year⁻¹) relative to annual litterfall C of 202.40 g C m⁻² year⁻¹ was marginally different among adjacent coniferous forests and reports from the literature.