Phenology of Tillandsia purpurea in association with microclimatic variables in a hyperarid environment of the southern Peruvian coast

Tillandsia purpurea is an endemic species of the Peruvian desert coast, where its main source of water and nutrients is supplied by ocean fog. It is a poorly studied species, and its phenological changes in response to different abiotic factors, including temperature and water availability, are unknown. This study aims to describe the different phenological phases and their relationship with some environmental factors including fog, precipitation, temperature, and humidity. This study was developed in a hyper-arid environment of the southern coast of Peru. We evaluated the fog water available using fog collectors (neblinometers) installed next to each cushion of T. purpurea , and also monitored the microclimate conditions at ground level with temperature and humidity sensors. Additionally, phenophases (inflorescence, flowering, fructification, dehiscence, and vegetative stage) were evaluated within ten cushions of T. purpurea for a period of eleven months. As for water availability, the average fog water collected by the fog collectors was 5.11 L•0.25m 2 month –1 and the accumulated precipitation was 35.8 mm. In the microclimate, the mean temperature was 18.4ºC and humidity was 62.5%, and seasonality was observed in the evaluated variables. The T. purpurea phenological phases recorded showed a certain synchrony with some microclimate variables and water availability. The vegetative and dehiscence stages were associated with lower-frequency months, fog volumes, and also with less-warm periods Moreover, the phenophases of inflorescence, flowering, and fructification occurred in the months with higher water availability from fog, precipitation, and associated with warmer periods; in the specific case of fructification, it was more associated with periods of maximum or medium relative humidity.