Floristic and functional identity of rupestrian grasslands as a subsidy for environmental restoration and policy

Abstract

The unique vegetation of rupestrian grassland (Campo Rupestre) is finely tuned to the strong environmental and edaphoclimatic filters that resulted in important adaptations and high levels of endemism. In this study, we intend to give another focus to the understanding of the identity of the rupestrian grasslands by observing their floristic relationships with other surrounding vegetation types and to present for the first time a functional approach and zeta similarity to try to understand the differences and similarities of this ecosystem with other adjacent ones. We have compiled 1790 plant species in 7 vegetation types. Based on the species composition, we can infer that the most similar vegetation types were Tepuis and Altitudinal Grasslands, and this group is closer to Inselbergs. Subsequently, the most similar were Ironstone Grasslands and the Atlantic Forest grouped with Quartzite Grasslands. Finally, Cerrado was the lesser similar. But, these groupings are modified when analyzed at genus or family level. Considering the zeta diversity decline at the species level, the vegetation types showed an almost complete turnover in species assemblage, sharing only a small suite of species between them. This pattern is similar at the genus level, but the number of genera shared across vegetation types is comparatively higher. On the other hand, at the family level, there is a common core of families shared between vegetation types. When we evaluated the similarity considering functional attributes we found differences in composition regarding growth and life forms. However, in this case, Quartzitic and Ironstone Rupestrian Grasslands showed very similar functional attributes. They are inhabited by plant species with shrub, epiphytic, parasitic and succulent forms with rupicolous growth form. In general, the quartzitic grasslands have singular vegetation, but its affinity with other vegetation types does not translate in any way the most relevant aspects associated with endemism and biodiversity. The true landscape identity to a certain ecosystem is given by functional characteristics.