Population structure and spatial distribution of tucumã-do-pará (Astrocaryum vulgare Mart.) in Salvaterra, Marajó island, Pará.

Astrocaryum vulgare Mart. is a palm tree that tolerates multiple environmental conditions, with complex development characteristics. The objective is to understand the population structure, the spatial distribution of this species in different environments and the effect of environmental gradients on its occurrence on Marajó Island, Pará. The hypothesis is that the population density of the species, as well as the spatial distribution, depends on the environment in which it is inserted. The study was carried out in 11 communities of residents of five different physiognomies, in which all individuals belonging to 42 sample units were mapped, measured and were categorized in height classes for further analysis. The results showed an abundance of juvenile individuals and a spatial distribution grouped across all physiognomies. The evidence points to a growing population, probably influenced by anthropic actions. Variables such as vegetation index of normalized difference, slope and distance from rivers were shown to be linked to the development of morphological characteristics. Finally, the occurrence of this species in physiognomies may be linked to the land use system, as it contributes to the creation of favorable environments for its development and, although differently, it has shown a high degree of adaptation to atypicals.

Saprobic conidial fungi associated with palm leaf litter in eastern Amazon, Brazil.

Fungi play an important role in litter decomposition in forest ecosystems and are considered an undersampled group in the Amazon biome. This study aims to describe the composition, richness and frequency of species of conidial fungi associated with palm trees in an area of ​​the Amapá National Forest, State of Amapá, Brazil. Palm leaf litter was collected from July 2009 to June 2010, incubated in moist chambers and examined for the presence of fungi. One hundred and seven species of conidial fungi were identified, in 79 genera and 25 families. As for the relative frequency of the species, the majority (94.4%) was sporadic and occurred on leaflets. We report new records for South America (Chaetopsis intermedia, Chaetochalara laevis and Thysanophora verrucosa) and Brazil (Chloridium phaeosporum, Helminthosporiella stilbacea and Zygosporium geminatum), and 83 for the State of Amapá, while 15 are also new for the Brazilian Amazon. This study significantly increases the knowledge about the distribution of the fungal species in the Amazon biome, and emphasizes the importance of the conservation of these organisms particularly in view of the large number of sporadic species recorded.