Resumen

DEZZEO, Nelda; FLORES, Saúl  y  CHACON, Noemí. Seedlings dynamics in undisturbed and adjacent fire disturbed forest in the Gran Sabana, Southern Venezuela.. INCI [online]. 2008, vol.33, n.4, pp.273-279. ISSN 0378-1844.

In the Gran Sabana, southern Venezuela, the conversion of large forest areas to a mosaic of forest, bush vegetation and savanna ("savannization") is a critical environmental issue associated with forest fires. Little is known about the behaviour of the seedling community in undisturbed and fire impacted forests in this region. Recruitment, survival and growth of seedlings was followed over a 6 year period in permanent quadrats established in undisturbed and adjacent fire-disturbed (secondary) forest. At the beginning of the study, secondary forest showed lower (P<0.05) values of seedling abundance and tree seedling richness than undisturbed forest. Abundance and species richness of tree seedling in both forests changed very little over the study period, which is associated to the partial balance between initial tree seedlings mortality rate (44-66%) and newly recruited tree seedlings survival rate (47-54%). At the end of the study ~80% of the recruited seedlings in undisturbed forest corresponded to tree species, whereas in secondary forest the proportions of tree (47%) and non-tree (53%) seedlings were rather similar. Growth in height during the 6 year period was considerably higher in secondary forest than in undisturbed forest (P<0.05). It is concluded that in undisturbed forest the succession process is relatively at a standstill, whereas in secondary forest this process advances very slowly.

Palabras clave : Forest Disturbance; Forest Dynamics; Seedling Survival; Seedling Growth; Seedling Recruitment; Tropical Forest.