Fitossociologia e análise temporal do fragmento florestal urbano capoeira do black, Belém, Pará.

Abstract

Urban forests are a reflection of land use and occupation processes, which have fragmented and isolated vegetation into small remnants in urban centers, as a result, these areas become increasingly vulnerable to extinction. Due to their ecological, economic and social importance, these fragments are intensely threatened by diverse anthropic and natural factors, such as visitation, predation, exploitation, pollution with garbage, introduction and propagation of exotic species, as well as geographic isolation to gene flow), border effects and microclimate altered by the urban environment. Due to these issues, this dissertation aims to characterize the floristic composition, diversity, horizontal structure, successional stage and soil occupation dynamics of the Black Capoeira forest fragment, a secondary forest area located in the periurban zone of the municipality (100% intensity inventory), measuring all individuals with a diameter greater than or equal to 15 cm and a Sampling Inventory of eight permanent plots (50 x 50 m), of which 4 were located at the border and 4 located inside the fragment, with a measurement of individuals with a diameter greater than or equal to 5 cm. All species were classified into ecological groups, subdivided between: pioneer species (P), early secondary (Si), late secondary (St) and climax species (C). Regarding the composition and richness, a species listing was made and the sample representativity was calculated among the different sample units. Soil occupation dynamics were performed based on the Isodata method (unsupervised classification of satellite images). As main results, 2,163 individuals, 171 species, were distributed in 51 families and 2,309 individuals, 186 species and 52 botanical families were found in the sample. The Shannon diversity index calculated for the area was from H '= 4.35 nats.ind to an equability of J' = 0.83, indicating a high floristic diversity in the area. The group of species with the highest prevalence was the late secondary ones for both the Census and the sampling and through the multitemporal analysis of the soil cover it was possible to verify that of the 8.50 hectares of area that compose the fragment, 8,15 ha or 95 , 8% is classified as secondary forest in the middle stage of regeneration. The main conclusions of this research are that the Black Capoeira forest fragment presents dendrometric parameters of density and basal area with approximate values to those found in remnants of primary and secondary forests of the Amazon region, the border environment presented structural-floristic parameters in a little superior to the interior environment, except for the parameter basal area that was larger inside the fragment and through the analysis of the successional stage and soil cover dynamics, we conclude that the fragment is in good conservation status species and it is suggested that new measures be taken to preserve the biodiversity of this urban forest fragment.