Effect of moss crusts on mitigation of post-fire soil erosion

Abstract

Mosses and wildfires are ubiquitous occurrences. Their correlation has been assessed in few studies. Mosses have been pointed as pioneer species in post-fire environments. However, reasons for moss crusting in post-wildfire soils and their ecosystem role in preventing soil erosion have not been quantitatively assessed. Moss crusts have quickly developed after a wildfire in a hillslope of eucalypt plantations, in central Portugal. This study had as the overarching aim comparing post-fire soil erosion and runoff between different moss cover percentages, combined with other protective cover elements throughout the first year after fire. Overland flow, sediment and organic matter losses were examined at micro-plots presenting different moss cover percentages, both between plots (11–46% in average) and across time (0–75%). While development of moss cover tended to increase the runoff response, a moss cover above 67% significantly reduced sediment and organic matter losses by 65% (0.40 Mg ha−1) and 34% (0.15 Mg ha−1) respectively, especially during the rainiest season. Given that mosses are very fast soil colonizers after wildfires, these results provide clues for considering moss crusts in post-fire management and demonstrate their importance in ecosystem restoration, including prevention of soil loss.