Seed bank responses after clearcutting Pinus patula plantations in Andean high montane areas

Abstract

Clear cutting exotic plantations favours natural regeneration processes in which seed banks may play an important role. In Andean high montane areas, after Pinus patula clear cutting, changes in soil pH and litter lead to increased fauna and flora biodiversity. However, the impactof these changes on seed banks remains unknown. The aims of the present study were to understand how seed bank richness, abundance, and composition changes after p. patula clear cutting, and to identify the role of above ground cover, pH and litter cover on these seed bank variations. The study was conducted in three areas with different post-clear cutting ages (0,2.5,4.5 years), a p. patula plantation and in a high Andean forest patch. All these sites were located between 3033 and 3100 m.a.s.l. Seed bank abundance, richness and the number of seeds of the ten most abundant species increased in areas with 2.5 and 4.5 years after clear cutting. Moreover, seed bank composition was different among study areas. These changes were related to increasing above ground vegetation cover and soil pH, and to decreasing litter cover. Seed banks contributed almost exclusively to the recovery of some herbaceous species; were corded only one tree species recruit from the seed banks (Baccharislatifolia) in the forest soils; therefore, the natural regeneration processes may be constrained. Our results high light the need to implement active restoration to accelerate high montane forest recovery in areas previously covered with pine tree plantations.