Biodiversity dynamics across environmental gradients and under impending environmental change

We live in a time of radical changes and rapid biodiversity loss. To make better predictions of the impacts of anthropogenic change on the world's declining biodiversity, it is crucial to first understand how species are naturally distributed and then assess how their distribution might shift or, worse, disappear. Biodiversity is unequally distributed across the Earth, increasing towards low latitudes, low to intermediate elevations, and intermediate canopy heights within forests. These spatial gradients reflect differences in environmental variables, such as luminosity, temperature and humidity, which affect physiological, demographic, and biotic interaction processes. Species show different preferences for these variables (i.e. ecological niche), which causes biodiversity to peak in areas of high niche overlap, provided that coexistence mechanisms are at play. Both niche-related variables and coexistence mechanisms are being disrupted by humans. Because many environmental variables naturally co-vary, contrasting gradients should provide insights to disentangle their roles in biodiversity dynamics under a changing world. Therefore, this project takes advantage of 1) novel mechanistic models than can simulate contrasting environmental gradients and 2) a biological system of major ecological importance - vascular epiphytes. Vascular epiphytes, including most orchids and bromeliads, are plants growing non-parasitically on trees. They are key to nutrient cycles and interaction networks in tropical forests, accounting for 10% of world's flora and up to 50% of some local floras. They vary in how they are distributed along vertical and elevational gradients, probably following their temperature and humidity preferences and often being geographically restricted (i.e. endemic and threatened). Epiphytes have been understudied due to difficulties in sampling the forest canopy despite being particularly vulnerable to deforestation and global warming. Hence, simulation experiments are ideal to improve our ecological understanding of the system while also to i) identify the data collection that should be prioritized in empirical studies and ii) explore scenarios of human impacts without manipulating vulnerable biodiversity.