Ecophysiology of Campos Rupestres Plants

Abstract

Campos rupestres are rocky seasonally-dry environments that occur over mountaintops in central Brazil. Plant growth is limited and prone to fire during the dry winter, and soils are severely nutrient-impoverished. Plants in these habitats exhibit a wide range of strategies to cope with these limitations. Campos rupestres plants show different rooting depths, according to plant habit and substrate. Water status in plants varies between stable water potentials in isohydric species to water potentials changing according to air humidity in anisohydric plants, some of them being dessication-tolerant and dormant during the dry season (resurrection plants). Carbon assimilation in the dry season is therefore limited by water availability, especially in dessication-tolerant species. A wide variety of mineral nutrition strategies allow effective nutrient acquisition in campos rupestres: mycorrhizas, non-mycorrhizal sand-binding root specializations, symbiotic nitrogen fixation, carnivory, parasitism. The incidence of natural fires may have played a role in the ecological and evolutionary processes that have molded the current flora of campos rupestres, as well as the occurrence of specific functional traits in these habitats. Unveiling the relative importance and prevalence of in situ adaptation and adaptive divergence in the lineages that diversified in campos rupestres will allow us to further discuss mechanisms related to trait evolution and adaptive radiation in campos rupestres.