NATIVE COLONIZING SPECIES AND DEGRADED LAND RESTORATION IN LA-GRAN-SABANA, VENEZUELA

We evaluated the ecological and reproductive characteristics of plant species occurring in severely disturbed areas that were revegetated wi th exotic grasses. We identified those species with the best combinati on of attributes that increase their probability of success in degrade d lands. Fifteen degraded areas were studied in two different bioclima tic regions, a high premontane humid bioclimate and a low premontane h umid bioclimate. The frequency of native colonizing species and the pr esence of arbuscular mycorrhizal colonization in their roots were eval uated. The sexual and breeding system, pollination mode, fruit set, an d dispersal syndrome of ten of the most frequent colonizing species we re also studied. The floristic survey of the colonizing species reveal ed a similarity to the reported flora of the treeless savannas that ar e dominant in the region. Bioclimatic conditions prevailing in the deg raded lands seem to be an important factor for the presence of coloniz ing species and for species richness. All colonizing species studied w ere mycorrhizal, and for this reason the restoration program in these degraded areas should take mycorrhizae into account, reintroducing the m or manipulating the soils to increase the mycorrhizal inoculum. We s uggest Scleria cyperina and Trachypogon plumosus to start or promote t he natural succession in the degraded areas from La Gran Sabana. Becau se their frequency is high and their reproductive system is less depen dent on biotic factors, these species stand out in the studied areas.