Fenologia de espécies arbóreas do dossel e Sub-dossel em um fragmento de mata Atlântica semi-decídua em Caratinga, Minas Gerais, Brasil

Couto-Santos, Fabiana

Abstract

The great diversity of plant species in tropical rainforests translates into a great variety of phenological patterns. These patterns are affected by several biotic and abiotic factors. Plant species in different functional groups and dispersion syndromes possess distinct morphological and physiological adaptations since they experience different microclimatic conditions, thus responding differently to local climatic conditions. With that in mind, the objective of this study was to compare the phenology of tree species occupying different strata in the forest and asses the influence of climatic factors such as rainfall, days of rain, temperature, and photoperiod on these phenological patterns. A total of 1098 individual trees with diameter at breast height (DBH) > 10 cm in a 3 ha sample were monitored for 3 years, between April 2002 and May 2005 in a semi-deciduous Atlantic Forest Fragment in Caratinga, Minas Gerais, Brazil. The sample included 46 tree species, where 30 were canopy species and 16 sub-canopy species. Every month, the presence/absence as well as the estimated quantity (in a scale of 0 to 4) of mature and young leaves, leaf buds, flowers, flower buds and immature, and mature fruits on each individual sampled tree, were recorded. Time series analysis was employed to study intra and inter annual variation in plant part production between strata. The vegetative phenophases, i.e. leaf fall and new leaf production, were correlated and did not differ in terms of time of occurrence between the strata in spite of its greater intensity on the canopy due to the greater number of deciduous species in this stratum. Leaf fall was more intense from July to November whereas budding from October to December. Considering the reproductive phenophases, the sub-canopy was proportionately more productive and showing temporal variability when compared to the canopy. Such variability occurred because only one flowering and one fruiting peak were recorded for the canopy with a greater proportion of annual and supra-annuals species as opposed to two peaks of flower and fruits in the sub-canopy. Interannual variations in flower and fruit production correlated more closely to the frequency of flowering and fruiting than to climatic variables per se and were significant only for the canopy. Overall, the phenophases showed a markedly seasonal pattern associated to the strong climatic seasonality at the study site. Fruiting was least affected by climate suggesting that the timing of occurrence of this phenophase might be associated more closely to their dispersion syndromes in contrast to the other phenophases.

• Thesis Type: Thesis
• Deposit Date: Mar 19, 2024
• Keywords: Plant phenology, Flowering, Fruiting, Leaf fall, Flushing, Stratification, Life-forms, Canopy, Sub-canopy, Overstory, semi-deciduous Atlantic Forest, climatic seasonality.
• Award Date: Sep 3, 2007