Climate change (CC) in the tropics have induced an increase in temperature and drought periods. These climatic modifications can produce changes in species distribution and mortality. While a modification in the floristic composition has already been reported, such as the increasing in liana abundance, the underlying physiological processes remain unclear. In this context, both plant thermal and hydraulic sensitivities could be key function in understanding how species behave under our changing climate. Recent studies have identified traits that well describes a species thermal and hydraulic tolerance such as the temperature at which 50% of the efficiency of photosystem II has declined (T50), and the water potential at which 50% of xylem conduits have embolized (P50) respectively. However, studies have yet to incorporate these traits in the context of species’ safety margins in tropical forests.

Here, we want to identify the thermal and hydraulic safety margins (i.e., the difference between T50 or P50 and the maximum observed value in natura) for adult canopy trees, saplings of canopy trees which represent the forest of the next century, and lianas. Moreover, we hypothesize that understory specialist species will be more vulnerable to an increase in air temperature, as they are adapted to the buffered environment of the forest understory.

Our project aims to evaluate the possible change in functional composition and plant biodiversity in the context of CC regarding both thermal and hydraulic safety margin.