Mulch application as post-fire rehabilitation treatment does not affect vegetation recovery in ecosystems dominated by obligate seeders

Mulching treatments have been successfully tested for reducing soil erosion in the first years after fire. However, little is known about their possible negative effect on vegetation regeneration. The aim of this work is to assess the effect of mulch application (woody chips) on the regeneration of Mediterranean Basin ecosystems dominated by obligate seeders. For this purpose, two different mulch ratios (1 and 2 kg m−2) were applied immediately after fire as a post-fire rehabilitation treatment. Soil micro-environmental modifications were tested by monitoring soil temperature and moisture. Vegetation regeneration was assessed by monitoring seedling emergence, seedling establishment, species richness and plant cover during the following three years. Mulch application modified micro-environmental conditions as soil temperature lowered and soil moisture increased. However, no significant effects were found in the final establishment of individuals, plant cover and species richness. In addition, application ratios of 2 kg m−2 increased the seedling survival of obligate seeders species. Mulch application reduced only seedling emergence in one species (Cistus albidus) in the 2 kg m−2 treatment, but did not affect final establishment. The lack of negative effects on vegetation regeneration is of paramount importance in the ecosystems studied as all plant individuals die and the root system protecting the soil must be completely restored by new individuals. Rapid vegetation establishment and growth will help reduce the “window of disturbance” for soil erosion, which occurs until vegetation is recovered. In conclusion, woody chip applications may be a suitable post-fire rehabilitation treatment as they have no negative effects on vegetation regeneration.