Distinct ecophysiological strategies of widespread and endemic species from the megadiverse campo rupestre

Abstract

The Espinhaço Mountain Range in eastern Brazil hosts a megadiverse and endemic tropical flora. The main vegetation is the campo rupestre, which harbors several endemic plant species. In this study, we sought to compare photosynthetic and leaf nutrient-use strategies in widespread and endemic species that allow its adjustments to high light and impoverished soils in campo rupestre. Three species with contrasting levels of endemism were selected: Coccoloba cereifera, an endangered micro-endemic species from Serra do Cipó; Lavoisiera cordata, vulnerable and endemic to Espinhaço range; and Vochysia thyrsoidea, a common widespread species from the Cerrado domain. During the dry season, we performed field measurements of chlorophyll a fluorescence and pigment content to evaluate the photosynthetic efficiency of these species. We also assessed soil fertility, nutrient status and leaf anatomy. Widespread and endemic species in campo rupestre showed distinct strategies to cope with high light levels and nutrient-impoverished soils. The micro-endemic species C. cereifera showed high nutrient use efficiency, which enables it to colonize impoverished sandy soils. This species and L. cordata minimize excessive light absorption at midday through shoot architecture as well as present efficient non-photochemical energy dissipation during high light level exposures. The high effective quantum yield and electron transport rate of the widespread species V. thyrsoidea may account in part for its wide distribution under extreme environmental conditions in Neotropical sites. The occurrence of widespread and endemic species in this megadiverse mountain environment might be attributed to distinct physiological strategies of species to cope with high light levels and impoverished soils.