Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity

Nature advance online publication 11 December 2017. doi:10.1038/nature24668

Authors: Adam F. A. Pellegrini, Anders Ahlström, Sarah E. Hobbie, Peter B. Reich, Lars P. Nieradzik, A. Carla Staver, Bryant C. Scharenbroch, Ari Jumpponen, William R. L. Anderegg, James T. Randerson & Robert B. Jackson
Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the frequency of fires was altered at each site. We find that frequently burned plots experienced a decline in surface soil carbon and nitrogen that was non-saturating through time, having 36 per cent (±13 per cent) less carbon and 38 per cent (±16 per cent) less nitrogen after 64 years than plots that were protected from fire. Fire-driven carbon and nitrogen losses were substantial in savanna grasslands and broadleaf forests, but not in temperate and boreal needleleaf forests. We also observe comparable soil carbon and nitrogen losses in an independent field dataset and in dynamic model simulations ...

Source: Nature AOP - December 11, 2017 Category: Research Authors: Adam F. A. Pellegrini Anders Ahlstr öm Sarah E. Hobbie Peter B. Reich Lars P. Nieradzik A. Carla Staver Bryant C. Scharenbroch Ari Jumpponen William R. L. Anderegg James T. Randerson Robert B. Jackson Tags: Letter Source Type: research