Variation in thermotolerance in woody plants from a seasonally dry tropical forest

Abstract

Temperature is expected to increase by 3 to 6°C by 2100 in tropics. Tropical species which are already near their upper temperature threshold are expected to experience temperature above their tolerance limit. Tropical forests are major carbon sink and their decline can have a positive feedback on global warming. So it is important to study the effect of higher temperatures on tropical tree species so as to predict forest dynamics under future high temperature. This study tries to understand the variation in thermotolerance of 38 coexisting woody perennial species that differ in leaf habit (evergreen and deciduous) and life form (shrubs, lianas and trees). I also check for ability to recover from heat damage and the possible correlation between thermotolerance and key leaf functional traits. The temperature at which performance drops to 50% (T50) ranged from 44.5 to 50.5°C. Lianas and trees showed higher thermotolerance than shrubs. The evergreen tree species had higher thermotolerance than deciduous tree species. More over a positive correlation was found between thermotolerance and LMA and LDMC. Most species did not show any recovery from heat damage. The maximum reported temperature of the region is close to the T50 of many species and they are at the risk of irreversible leaf damag