Responses in Soil Carbon and Nitrogen Fractionation after Prescribed Burning in the Montseny Biosphere Reserve (NE Iberian Peninsula)

Prescribed fire is one of the most widely-used management tools to recover encroached rangelands. Fire has been reported to cause changes in the soil physical and chemical properties. However, the legacy effects of former plant species on soil responses to fire remains unknown. The legacy effect of the former extant plant species on soil carbon (C) and nitrogen (N) fractionation distribution after prescribed burning in topsoil (0-5 cm and 5-10 cm) was investigated in Mediterranean shrublands in Montseny. We sampled soils under five vegetation patch types: Cytisus scoparius L., Calluna vulgaris L., Erica arborea L., Pteridium aquilinum L., and Cladonia biocrusts, pre- and post-burning. Multivariate analysis on soil C and N fractions showed that soils under the legume Cytisus and the biocrust were the most differentiated. Vegetation patch types tended to respond differently to burning, soils under Cytisus, Cladonia and Calluna showing the strongest response. Total C and N, and C and N in sand decreased after burning in the 0-5 cm soil layer. Conversely, C in silt, as well as N in clay and silt, increased with soil depth after burning. This study will be helpful for understanding ecological legacy effects and their possible consequences when planning prescribed burning.

Automated summary

This study investigated the legacy effects of former plant species on soil carbon and nitrogen distribution after prescribed burning. The results showed that different vegetation patch types responded differently to fire, with legume species and biocrusts showing the most distinct soil differences. After burning, total carbon and nitrogen, as well as carbon and nitrogen in sand, decreased in the 0-5 cm soil layer, while carbon in silt, as well as nitrogen in clay and silt, increased with soil depth.