J Syst Evol

• Research Article •    

On the rocks: biogeography and floristic identity of rocky ecosystems in eastern south America

Luísa Azevedo1*, Daniela Cristina Zappi2, Daniela Melo Garcia de Oliveira1, Leila Meyer3, Eimear Nic Lughadha4, Rosie Clegg4,5, Leonardo Dias Meireles6, Pablo Hendrigo Alves de Melo7, R. Toby Pennington5,8, Danilo M. Neves1,3   

  1. 1 Postgraduate programme in Ecology, Conservation and Wildlife Management, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, 31270-901, BR;
    2 Postgraduate programme in Botany, Institute of Biological Sciences, University of Brasília, Brasília, Distrito Federal, 70910-900, BR;
    3 Postgraduate programme in Plant Biology, Institute of Biological Sciences, Federal University of Minas Belo Horizonte, 31270-901, BR;
    4 The Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK;
    5 Geography, University of Exeter, Laver Building, North Park Road, Exeter, EX4 4QE, UK;
    6 Environmental Management Course, School of Art, Science, and Humanities, University of São Paulo, São Paulo, 03828-000, BR;
    7 Centro Nacional de Conservação da Flora, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, BR;
    8 Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh, EH3 5LR, UK
    *Correspondence: Luísa Azevedo, Postgraduate programme in Ecology, Conservation and Wildlife Management, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, 31270-901, Brazil. E-mail: luisaazevedomeyer@gmail.com
  • Received:2023-06-30 Accepted:2023-12-11

Abstract: The geodiversity of rocky ecosystems includes diverse plant communities with specific names, but their continental-scale floristic identity and the knowledge on the role of macroclimate remain patchy. Here we assessed the identity of plant communities in eastern Brazil across multiple types of rocky landscapes and evaluated the relative importance of climatic variables in constraining floristic differentiation. We provided lists of diagnostic species and an assessment of the conservation status of the identified floristic groups. We compiled a dataset of 151 sites (4,498 species) from rocky ecosystems, including campos rupestres, campos de altitude, granitic-gneiss lowland inselbergs and limestone outcrops. We used unsupervised clustering analysis followed by ANOSIM to assess floristic groups among sites. We performed a random forest variable selection to test whether the identified floristic groups occupy distinct climatic spaces. Six groups (lithobiomes) segregated floristically according to lithology and climate. Alongside campos de altitude and limestone outcrops, inselbergs were divided according to the biome in which they occur (Atlantic Forest or Caatinga) and campos rupestres were largely segregated according to their lithological matrix (ironstone or quartzitic). Plant communities of Caatinga inselbergs were more similar to limestone outcrops, while Atlantic Forest inselbergs communities resembled campos de altitude. The composition of plant communities on outcrops seems to be largely constrained by lithology, but climatic factors are also meaningful for sites with similar lithology. The current network of protected areas does not cover these unique ecosystems and their floristic heterogeneity, with protection least adequate for Caatinga inselbergs, ironstone campos rupestres and limestone outcrops.

Key words: campos de altitude, campos rupestres, inselberg, ironstone, karst, limestone outcrops, lithophytes, rupicolous plant communities, geodiversity