Zoomingin on quartzitic outcrops: micro-habitat influences on flora and vegetation

Clara Da Cruz Vidart Badia,Livia Echternacht,Maria Cristina Teixeira Braga Messias

doi:10.1590/2175-7860202172095

Clara Da Cruz Vidart Badia, Livia Echternacht + Show 1 more

Open Access

https://doi.org/10.1590/2175-7860202172095

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Abstract

Abstract Rock outcrop vegetation is recognized worldwide by its singular and biodiverse flora. Campo Rupestre forms hyperdiverse mosaics in rocky environments across a wide latitudinal and altitudinal gradient, with high species turnover at macro- and micro-scales. The surrounding biomes, climate, and geological formations are the main drivers of species turnover on a macro-scale while micro-habitat seems to be the main one determining the peculiarities of the Campo Rupestre on a micro-scale. In a quartzitic Campo Rupestre area we evaluate how the outcrop micro-habitats influence floristic composition and functional traits. The study area is located in the municipality of Ouro Preto, Minas Gerais state, southeastern Brazil. Two main outcrop habitats were considered: top surfaces, with bare rock, shallow depressions and ephemeral ponds; and lateral surfaces, with clefts and crevices. We recorded the vascular species, their respective life-forms (according to Raunkiaer’s system) as well as their coverage in 18 plots. We identified 71 species in 31 families. The floristic spectra and species composition were similar between top and lateral surfaces. There was no significant difference among the vegetational spectra. However, hemicryptophytes were slightly dominant on top, while on the sides chamaephytes were the dominant life-form. Understanding plant adaptations to these environments provides insights into the mechanisms underlying geomorphological heterogeneity in plant communities.

Highlights

Rocky outcrops present a vegetation pattern distinct from their surroundings, often selecting for xeric-adapted species that are able to survive harsh climatic conditions (Porembski & Barthlott 2000; Michael & Lindenmayer 2012)
The distinct geomorphological features formed by rock outcrops create micro-habitats that further enhance biodiversity (Burnett et al 1998)
Campo Rupestre presents an extremely biodiverse vegetation and is defined by the presence of rocky outcrops; they are recognized as a mosaic of micro-habitats, with many endemics and stenotopic species (Conceição & Pirani 2005; Conceição et al 2007; Echternacht et al 2011; Silveira et al 2016; Castro et al 2018)

Summary

Introduction

Rocky outcrops present a vegetation pattern distinct from their surroundings, often selecting for xeric-adapted species that are able to survive harsh climatic conditions (Porembski & Barthlott 2000; Michael & Lindenmayer 2012). Campo Rupestre presents an extremely biodiverse vegetation and is defined by the presence of rocky outcrops; they are recognized as a mosaic of micro-habitats, with many endemics and stenotopic species (Conceição & Pirani 2005; Conceição et al 2007; Echternacht et al 2011; Silveira et al 2016; Castro et al 2018). In the southern portion of Espinhaço Range, there is the Quadrilátero Ferrífero, a mountain complex of quadrangular relief and ferriferous or quartzitic rocks at mountaintops, located between the municipalities of Ouro Branco, Belo Horizonte, Catas Altas and Moeda. In spite of different geological origins for the Espinhaço Range and the Quadrilátero Ferrífero, they may be considered as a biogeographic unit (Echternacht et al 2011; Colli-Silva et al 2019)

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