Ademir Roberto Ruschel

Fenologia reprodutiva de espécies arbóreas em uma formação secundária da floresta Atlântica

Studies on reproductive phenology of tree species provide the knowledge needed to define strategies for forest conservation and management. Thus, the objective of this work was to characterize the reproductive phenology of woody species in secondary forests of the Atlantic Rain Forest. From June/1998 to July/1999, flowering and fructification periods of five to 41 reproductive trees of 19 species were evaluated in an area displaying vegetation characteristic of an advanced stage of succession, located in Sao Pedro de Alcântara - Santa Catarina. Flowering and fructification observations were made every other week. The proportion of plants that produced flowers and fruits ranged from 5.5% to 80.0% (average 28.4%), depending on the species. The minimum DBH for a plant to produce fruits ranged from 5.6 to 21.5 cm. For most species, flowering occurred between October and January and fructification from January to March. In addition to these factors, the reproductive phenophases are also dependent on the ecosystem where they grow. This is why several species showed different reproductive periods compared to those observed in other regions. Thus, this work stresses the need of specific studies for the elaboration of a forest management plan for native timber species and seed collecting strategies.

Woody plant species richness in the Turvo State park, a large remnant of deciduous Atlantic forest, Brazil

This paper presents a quantitative inventory of woody plants with DBHxa0≥xa05xa0cm in Turvo State park, a large remnant (17,500xa0ha) of seasonal deciduous Atlantic forest in Southern Brazil. The forest inventory was based on 141 sampling points (point centered quarter method). Seventy-eight species from 37 families were recorded, the density was 879 plantsxa0ha−1 and the basal area 25.12xa0m2xa0ha−1. Timber species of commercial value made up 35% of the species and 72% of the basal area. The ten most abundant species made up 52% of the species, and the ten species with highest basal area accounted for 48% of the total basal area and 12% of the species. Zoochory was the dominant mode of seed dispersal, representing 63% of species and 67% of the plant density. Nine percent of the species were pioneers, 56% were secondary species accounting for 62% of the total basal area, and 35% were opportunistic-climax species accounting for 54% of the plant density. Turvo park has exceptionally high biodiversity and is the last intact large remnant of the Alto-Uruguai river ecosystem. In addition to species richness and an abundance of high value timber species, this forest is of value for the rich genetic resources, and for medicinal and ornamental plants.

Secondary Forest Succession in the Mata Atlantica,Brazil: Floristic and Phytosociological Trends

This study aimed at understanding the dynamics of ecological processes and the use ofnsecondary forests in Santa Catarina state (Brazil). The data base for these studies was formednthrough forest inventories carried out in the three forest types of the state. The results of thisnstudy demonstrate that the patterns of diversity are very similar among the three forest types;nhowever, the species compositions among the types are quite different. A total of 343 woodynspecies belonging to 73 families were found in the 24,000u2009m2 sampling area, revealing thenpotential role of secondary forest in the conservation of biodiversity at the landscape scale.nAs expected, a small set of pioneer species dominates young secondary forests with shade-tolerantnspecies becoming structurally important after 30 years. The patterns of forest structurenand species diversity observed in study largely conform to the postagricultural secondarynsuccession observed for many tropical forests.

The Genetic Structure of Sorocea bonplandii in Southern Brazilian Forest Fragments: AFLP Diversity

Abstract To analyse possible genetic erosion due to fragmentation in the Brazilian Atlantic Forest ecosystem, we investigated the genetic diversity within and among one large and six small populations of one of the key species of this ecosystem, Sorocea bonplandii, using AFLP analyses of 468 plants. Eight primer pairs yielded 299 polymorphic fragments for analysis. S. bonplandii was characterized by an unusually high genetic diversity within the species and also within individual populations, around 94% of the total genetic diversity occurred within populations. Genetic distances between populations were low in spite of extensive fragmentation. Genetic distance was significantly correlated with geographical distances between fragments, but these differences may have existed before fragmentation. Our results have direct implications for sustainable management of S. bonplandii, indicating that conservation strategies might be based on a random sample of trees taken throughout the Atlantic forest. However, the minimum population size required for maintaining the huge genetic diversity of this species is unknown. In order to establish a sustainable management plan for the species, further ecological studies are needed.