Reproductive phenology variation of the multiple inflorescence-palm tree Wettinia maynensis in relation to climate, in a Piedmont forest in western Amazonia

Abstract

Wettinia maynensis’ phenology is influenced by temperature and the relative humidity, suggesting that the reproductive phenology can change in extreme climate event contexts, even in very humid unseasonal forests. Wettinia maynensis is a piedmont palm tree whose ecology, phenology and responses to climate are yet unknown. In order to examine the reproductive biology of this species, we observed the flowering and fruiting performance of 101 adult palms in the Colonso Chalupas Biological Reserve in the Ecuadorian Piedmont, located between the Andean mountains and the Amazon. All individuals were monitored every 1 or 2 months during 2.3 years (2015–2018). The inflorescences are infrafoliar with usually one central, large, pistillate and several lateral, centrifugally smaller, staminate inflorescences. Flowering took place throughout the year although staminate and pistillate inflorescences showed low synchrony towards the end of the year, 40% and 32%, respectively. Staminate inflorescences showed a negative strong relationship with relative humidity and a positive one with temperature. The infructescences exhibited high synchrony (80%) for almost 6 months. Compared to other species of the genus, W. maynensis presented the lowest ratio of male/female inflorescences, the higher production of infructescences but lower number of fruits per year. Infructescences production per palm was between cero and 7, and the time elapsed between the fruit formation and its dehiscence was about 5–8 months. Some palms were observed with simultaneously active pistillate and staminate inflorescences (21–22 palms), therefore geitonogamy is not discarded. Wettinia maynensis inflorescences production and its correlation with relative humidity, hence with temperature, highlights that crucial changes could occur in the reproductive phenology of this species under future climate change scenarios affecting the population dynamics and then the community of Andean–Amazon piedmont forests.