Abstract ID: 469

Effect of seven years of an experimental drought on Amazon rainforest belowground dynamics

Leading climate models predict large decreases in rainfall over the Amazon region this century. There is very little data, however, regarding the effect of drought on belowground carbon cycling in Amazonia, especially at depths beyond the surface layer. In this study, we investigate the response of seven years of an enforced drought at an experimental site in eastern Amazonia on 1) total belowground carbon stocks (coarse roots, fine roots and soil carbon) and root length density and 2) the vertical distribution of root length density, root biomass and soil carbon. We collected data in 8 depth increment classes to a total depth of 4 metres, by means of soil pits and cores. The results are analysed in the context of optimality theory, which predicts plants should allocate a relatively greater amount of their roots in less superficial soil layers, where water stress is less limiting. The implications of our results in terms of land surface model predictions of climate change over Amazonia are also considered.

Session:  Carbon - Forest dynamics, natural disturbance, and recovery.

Presentation Type:  Poster