ABSTRACT
We present a synthesis (2006-2012) of plant community dynamics in an area (1 ha) of the largest remnant of Atlantic Rain Forest surrounded by São Paulo city. Plants with ≥ 2.5 cm dbh, including the climbers, were sampled in 10 transects (2 × 50 m), and the smaller (> 1 m height, < 2.5 cm dbh) in 10 subtransects (1 × 50 m). We sampled 901 individuals, 125 species (38 families), 83 classified as late-successional species, 12 threatened with extinction and 56 absent in the area management plan, some Endangered (EN) species. The climbers were the most dynamics, they had the largest decrease in basal area; and the larger (> 5.0 cm dbh) and shorter (< 2.5 cm dbh) trees had the highest mortality rates of the shrub-tree synusia. Late species regeneration was predominant. The studied forest showed progression towards more mature successional stages in the monitoring period.
Nós apresentamos uma síntese (2006-2012) da dinâmica da comunidade vegetal em uma área (1 ha) do maior remanescente de Mata Atlântica cercado pela cidade de São Paulo. As plantas com dap ≥ 2,5 cm, incluindo as trepadeiras, foram amostradas em 10 transectos (2 × 50 m) e as menores (altura > 1 m, dap < 2,5 cm) em 10 subtransectos (1 × 50 m). Nós amostramos 901 indivíduos, 125 espécies (38 famílias), 83 classificadas como tardias, 12 ameaçadas e 56 ausentes no plano de manejo da área, algumas Em Perigo (EN) de extinção. As trepadeiras foram as mais dinâmicas, com a maior redução de área basal; e as árvores maiores (dap > 5,0 cm) e menores (dap < 2,5 cm) tiveram a maior mortalidade da sinúsia arbórea. A regeneração de espécies tardias foi a predominante. No período monitorado, a floresta estudada apresentou progressão para estádios sucessionais mais maduros.
ABSTRACT
Zoosporic organisms are commonly found in different aquatic ecosystems; however little is known about the influence of environmental factors and seasonal fluctuations on their occurrence and distribution. This study investigated patterns of abundance, frequency and diversity of these organisms and their relationship with some abiotic factors and seasonality in a cerrado remnant in Sao Paulo, Brazil. Water samples were collected at four dates in two areas of this remnant during the rainy and dry seasons, and 13 abiotic factors were analyzed. From 48 samples collected, 32 taxa were isolated with the multiple baiting technique. The community structure of the zoosporic organisms showed some changes in response to different spatial distribution and seasonal fluctuations, probably influenced by distinct abiotic characteristics of each area or climatic period. Still, the similarity between areas and seasons indicated by Sørensen index and diversity (richness, evenness, Shannon and Simpson indices) were high.
