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PHENOLOGICAL STRATEGIES OF DIOECIOUS SPECIES IN RESPONSE TO THE ENVIRONMENTAL VARIATIONS OF RUPESTRIAN GRASSLANDS

ESTRATÉGIAS FENOLÓGICAS DE ESPÉCIES DIOICAS EM RESPOSTA A VARIAÇÕES AMBIENTAIS DOS COMPLEXOS RUPESTRES

ABSTRACT

Rupestrian grasslands present great diversity of phenological patterns in response to the high biodiversity of this ecosystem and its environmental variation. Dioecious species show distinction between the genders in relation to the nutritional requirements for growth and reproduction, comprehending determining factors, especially in restrictive environments. The purpose of the study was to comprehend the reproductive and vegetative phenology of the dioecious species Baccharis playtypoda, joining the phenological strategies with the sexual system and the environment seasonal variations. The study was performed in three areas of rupestrian grassland, where the phenology of thirty plants from September/2010 through September/2011 was observed. The Fournier intensity method, Spearman’s correlation and circular analysis were used. The reproductive phenophases began in February and ended between September and October, while the vegetative phenophases presented intensity variation during that period. The vegetative phenophases of both genders has shown low seasonal standard, while the reproductive phenophases has presented strong seasonality. The species B. platypoda has presented little variations in the phenological strategies of male and female individuals, mainly during the reproductive phenophases and in the vegetative growth for the allocation of resources. The species’ reproductive phenology had been associated to some environmental variables, mainly for the fructification phenophases, while the vegetative phenology, in general, had been most associated to the reproductive phenology of the species.

Keywords:
Baccharis platypoda; Asteracea; Reproductive phenology; Vegetative phenology; Dioecious; Seasonality

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