Biotemas (Jun 2011)
Phenology and survival of three populations of ferns in fragment of Atlantic Forest, in Paraíba, Brazil
Abstract
With the goal of contributing to the conservation, and knowledge about the ecology, of seedless vascular plants in Brazil, the present study describes the results of an analysis of the phenology and survival rates of three populations of ferns (Acrostichum danaeifolium Langsd. & Fisch., Lygodium volubile Sw. and Thelypteris serrata (Cav.) Alston). The study was conducted in a fragment of the Atlantic Forest, in the state of Paraíba, during the dry and rainy seasons. Ten individuals from each population were tagged, and observed in the field over a 12-month period. Data about phenology and herbivory were recorded and related to seasonal climatological data. Survival rates and the most common causes of death were also recorded. The production of sterile fronds occurred during both seasons. Significantly greater production of these leaves was observed in L. volubile during the rainy season. Only A. danaeifolium produced fertile fronds with no significant difference between seasons. Foliar senescence continuously occurred with no significant seasonal differences in A. danaeifolium and T. serrata, whereas this phenophase only occurred in the rainy season in L. volubile. The fronds of A. danaeifolium were continuously attacked by herbivores, whereas those of L. volubile were only attacked during the rainy season. The lowest rate of death of the individuals studied occurred in A. danaeifolium (20%), whereas the highest rate occurred in T. serrata (40%). Desiccation and natural accidents were the main causes of death among the individuals (approximately 90%).
