Long-term monitoring of the columnar cactus Cipocereus minensis reveals unforeseeable reproductive phenology

Phenological studies with species of cactus have grown in recent decades but the number of species studied remains very low, considering the high species richness of this group. In addition, temporal patterns of flowering and fruiting are important to understanding the processes that govern these crucial events of plant demography and ecology. Based on a five-year study of the reproductive phenology of C. minensis we asked if there is seasonality of flowering and fruiting. Secondly, we tested which climatic variables trigger C. minensis reproductive events in the Espinhaço region. We found that not all individuals produced flowers and fruits each year and a few individuals contributed with most flowers. Flower and immature fruit production is higher during the dry months, with fruits maturing during the rainy season or just before. In general, phenological events were seasonal, except for mature fruit production in 2010 and flower production in 2011. Some phenological traits such as flower timing, frequency, duration, and timing of immature fruit production had not been reported for the genus Cipocereus and were detected only because of the long-term phenological observations. Phenological heterogeneity in cactus might be a response to annual climatic fluctuations, mainly rainfall.