Regeneração natural de espécies arbóreas em fragmento florestal da Zona da Mata Mineira / Natural regeneration of tree species in a Mountain Seasonal Semideciduous Forest fragment in the Atlantic Forest domain, southeastern Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Tree species natural regeneration floristic composition was studied in a Mountain Seasonal Semideciduous Forest fragment in the domain of the Atlantic Forest, in southeastern Brazil (2045 S, 4255 W) to subsidize forest management. Ten sites were selected based on aspect, slope and topographic position. Natural regeneration indexes were estimated for each tree species per size classes to obtain the Total Natural Regeneration Index (TNR) for each species. It was sampled 3,516 individuals of 140 species with the individuals size varying from 10 cm height to the maximum of 5 cm diameter at the height of 1.3 m. Floristic similarity among sites was based on the Sorensen coefficient, using a matrix with the TNR values. The relationship between species distribution and environmental characteristics was analyzed by using Canonical Correspondence Analysis (CCA). TNR and CNR were analyzed against the variables soil base saturation (V), photosyntetically active radiation transmittance (t%), topographic position (TP), slope (D) and phosphorus content in the soil (P). A statistical method was used to decide about the species to be included in CCA based on the overlap of two exponential models relating the number of individuals per species to the number of remaining species. The largest number of individuals were sampled in the families Rubiaceae, Leguminosae mimosoideae, Monimiaceae, Leguminosae papilionoideae, and the richest families were Leguminosae caesalpinoideae, Leguminosae papilionoideae, Euphorbiaceae, Lauraceae, Myrtaceae and Rubiaceae. Psychotria sessilis, Siparuna guianensis, Anadenanthera peregrina and Piptadenia gonoacantha presented the largest TNR. Five species occurred in all ten sites and some were site specific. Four site groups could be identified from the floristic similarity dendrogram. These groups seem to represent different successional stage and, the difference in similarity between sites within each group may be explained by differences in physiographic factors and soil characteristics. Although the studied forest fragment is older than 45 years, the anthropic influence on floristic composition is still evident. Physiographic and soilinfluence on floristic composition may be more evident at older ages. The ordination of the species in CCA suggested the distinction of two groups with opposite preferences in relation to t%, V and TP when analyzing RNT and RNC of the size class 1. Size class 2 and 3 did not present significant correlation with enviromental variables. The comparison of the actual regeneration study with that of prior evaluations suggests a continuous substitution of species from initial to more advanced stages. These results indicate that the protection of the remnant forest fragments is important to maintain or improve biodiversity in the region.

ASSUNTO(S)

análise de correspondência canônica composição florística floresta estacional semidecidual regeneração natural silvicultura natural regeneration seasonal semideciduous forest floristic composition canonical correspondence analysis

ACESSO AO ARTIGO

Documentos Relacionados