Banco de sementes em áreas de caatinga sob diferentes intervenções.

Abstract

The density, floristic composition and diversity of forest environments depend on the quality and quantity of natural regeneration. Several factors influence this process, depending on the successional stage of the forest and the interactions with the climate, physiography, soil, biotic factors, the impacts caused by man and animals and seedling resistance to the conditions of a certain area. The aim of this study was to compare the density, floristic composition and diversity of the seed bank in three areas of Caatinga subjected to different forms of intervention. This study was conducted in an area populated with native jurema preta (A1), degraded area in process of recovery with species native to the Caatinga (A2) and area with pasture degradation process devoid of woody vegetation and bare soil (A3 ), located in NUPEARIDO Farm, belonging to the Federal University of Campina Grande, Patos - PB. Five samples of litter + soil from each area were collected and taken to the UFCG nursery, Campus of Patos, for monitoring of seedling emergence for a period of 90 days under shading conditions and automatic irrigation. The total number of plants was compared between areas by 2 test (P <0.01) and floristic diversity of species were assessed using the Shannon-Wiener index (H '), evenness (e') and the Similarity Score of Søresen. The herbaceous species seed bank of the three studied areas showed an average density of 4257 seeds/m2, although in the jurema preta dominated area herb density much lower (310 seeds/m2). The degraded area had the highest density of grass seed, but the number of families and species was similar in all three areas. The jurema preta was the only tree species present in the three areas and the recovery process area showed higher diversity and evenness of species.