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) while considering the zonal distribution of plant species in a coastal dune ecosystem in western Japan, based on periodic R 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 increased exponentially along with the seasonal rise in soil temperature, but summer drought stress markedly decreased R in plots 3 and 4. There was a significant positive correlation between the natural logarithm of belowground plant biomass and R in autumn. Our findings indicate that the seasonal dynamics of R in this coastal dune ecosystem are controlled by abiotic factors (soil temperature and soil moisture), but the response of R to drought stress in summer varied among plots that differed in dominant vegetation species. Our findings also indicated that the spatial dynamics of R are mainly controlled by the distribution of belowground plant biomass and autotrophic respiration.