Abiotic and biotic factors controlling the dynamics of soil respiration in a coastal dune ecosystem in western Japan

In this study, we examined the abiotic and biotic factors controlling the dynamics of soil respiration (R-s) while considering the zonal distribution of plant species in a coastal dune ecosystem in western Japan, based on periodic R-s data and continuous environmental data. We set four measurement plots with different vegetation compositions: plot 1 on bare sand; plot 2 on a cluster of young Vitex rotundifolia seedlings; plot 3 on a mixture of Artemisia capillaris and V. rotundifolia; and plot 4 on the inland boundary between the coastal vegetation zone and a Pinus thunbergii forest. R-s increased exponentially along with the seasonal rise in soil temperature, but summer drought stress markedly decreased R-s in plots 3 and 4. There was a significant positive correlation between the natural logarithm of belowground plant biomass and R-s in autumn. Our findings indicate that the seasonal dynamics of R-s in this coastal dune ecosystem are controlled by abiotic factors (soil temperature and soil moisture), but the response of R-s to drought stress in summer varied among plots that differed in dominant vegetation species. Our findings also indicated that the spatial dynamics of R-s are mainly controlled by the distribution of belowground plant biomass and autotrophic respiration.