Functional traits and adaptive capacity of cloud forest Ternstroemia species in response to climatic variation

Tropical Mountain Cloud Forests (TMCFs) produce distinct climatic gradients that can both constrain and facilitate the presence of tree species and/or specific combinations of functional traits. Local climatic adaptation allows for maximum fitness under hydric stress, resulting in specific morphological adaptations to the TMCF tree species. In this study, we assessed the hypothesis that the functional traits of two uncommon TMCF species (Ternstroemia huasteca and T. sylvatica) would show similar morpho-anatomical adjustments to climate variation. Our research questions were: how do the Ternstroemia functional traits vary interspecifically between TMCFs? Which of these two species is the most climatically vulnerable? To answer these questions, we examined differences in wood anatomical traits and leaf vascular tissues between both species. For this, we assessed the effects of temperature, precipitation, and evapotranspiration on the functional traits of Ternstroemia in different TMCFs. Our analyses suggested that, not all climatic factors considered affected the functional traits of Ternstroemia at the same magnitude. These findings provide insights into the ecophysiological functional trait adaptation mechanisms in response to hydraulic deficit in TMCF understory tree species.