The study of periodic vegetative and reproductive changes in plants in relation to climatic changes throughout time is generally known as phenology. Research of phenological patterns of plant growth and reproduction is critical to understand the processes related to forest succession and the functioning of ecosystems. Tropical dry forests are among the most threatened ecosystems of the planet and little is known about the changes on phenology across the different successional stages in tropical dry forest. In this study, we asked the following: how successional changes affect plant phenological patterns (mean peak, seasonality, and duration) and pollination and seed dispersal syndromes? From June 2006 to March 2010, we made monthly phenological recordings (flowers in anthesis, mature fruits, and leaves) at three successional stages: early (3-5 years since abandonment at the beginning of the study), intermediate (8-12 years) and late (more than 50 years). We used circular statistics and generalized linear models to analyze and compare the phenological patterns and the frequency of dispersal and pollination syndromes between successional stages. The influence of environmental factors on plant phenology was examined using Spearman’s correlations. Finally, we use Mantel tests to evaluate the association between phylogenetic and phenological events.
Results/Conclusions
We find that the mean peak of flowering, fruiting and leafing showed differences between different years of study, only in the early successional stages. Mean peak, seasonality, and duration of flowering and fruiting were significantly different in the late stage compared with the early and intermediate stages. The presence of leaves was positively related to rainfall and temperature in the three successional stages. We did not find a significant relationship between phylogenetic and phenological distances. Flowering was positively correlated to the precipitation in the early stage, and to the day-length in the intermediate and late stages. The presence of mature fruits was negatively related to rainfall and temperature in the three successional stages. Biotic syndromes associated to seed dispersal and pollination were the most frequent in all successional stages, and did not show a seasonal pattern. Our findings illustrate that high variation in the reproductive phenological patterns are associated with the successional stages and although the intermediate and late successional stages are floristically more similar, they are phenologicallly different.