Can salvage logging affect seed dispersal by birds into burned forests?

摘要

The recovery of vegetation in Mediterranean ecosystems after wildfire is mostly a result of directregeneration, since the same species existing before the fire regenerate on-site by seeding orresprouting. However, the possibility of plant colonization by dispersal of seeds from unburned areasremains poorly studied. We addressed the role of the frugivorous, bird-dependent seed dispersal (seedrain) of fleshy-fruited plants in a burned and managed forest in the second winter after a fire, beforeon-site fruit production had begun. We also assessed the effect on seed rain of different microhabitatsresulting from salvage logging (erosion barriers, standing snags, open areas), as well as the micro-habitats of unlogged patches and an unburned control forest, taking account of the importance ofperches as seed rain sites. We found considerable seed rain by birds in the burned area. Seeds, mostlyfrom Olive trees Olea europaea and Evergreen pistaches Pistacia lentiscus, belonged to plants fruitingonly in surrounding unburned areas. Seed rain was heterogeneous, and depended on microhabitat, withthe highest seed density in the unburned control forest but closely followed by the wood piles oferosion barriers. In contrast, very low densities were found under perches of standing snags.Furthermore, frugivorous bird richness seemed to be higher in the erosion barriers than elsewhere. Ourresults highlight the importance of this specific post-fire management in bird-dependent seed rain andalso may suggest a consequent heterogeneous distribution of fleshy-fruited plants in burned andmanaged areas. However, there needs to be more study of the establishment success of dispersed seedsbefore an accurate assessment can be made of the role of bird-mediated seed dispersal in post-fireregeneration.