Cattle and weedy shrubs as restoration tools of tropical montane rainforest

Over the last 150 years, a large proportion of forests in Latin America hav e been converted to pastures. When these pastures are abandoned, grasses ma y slow reestablishment of woody species and limit forest regeneration. In t his study, we explored the use of cattle in facilitating the establishment of woody vegetation in Colombian montane pastures, dominated by the African grasses Pennisetum clandestinum (Kikuyo) and Melinis minutiflora (Yaragua) . First, we described woody and herbaceous vegetation in grazed and non-gra zed pastures. Second, we tested the effect of grazing and seed addition on the establishment and growth of woody species. We also determined if the ef fect of grazing was different in P. clandestinum and M. minutiflora pasture s. We found that low stocking density of cattle greatly increased density, number of branches per individual (a measure of "shrubiness"), and basal ar ea of woody species, but also reduced woody plant species richness and dive rsity. In the grazed area, the shrubs Baccharis latifolia (Chilca) and Salv ia sp. (Salvia) were the most abundant. The combined effect of grazing and shading from the shrubs reduced herbaceous vegetation by 52 to 92%. In the grazing/seed addition experiment, grazing increased establishment of woody seedlings, particularly of the shrub Verbesina arborea (camargo), but the l argest effect was seed addition. Where grasses are an important barrier to regeneration, grazing can facilitate the establishment of shrubs that creat e a microhabitat more suitable for the establishment of montane forest tree species.