J Syst Evol ›› 2024, Vol. 62 ›› Issue (2): 305-320.DOI: 10.1111/jse.13052

• Research Articles • Previous Articles     Next Articles

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, and Danilo M. Neves1,3   

  1. 1 Programa de Pós-Graduação em Ecologia, Conservação e Manejo da Vida Silvestre, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil;
    2 Programa de Pós-Graduação em Botânica, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília 70910-900, Brazil;
    3 Programa de Pós-graduação em Biologia Vegetal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil;
    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 Gestão Ambiental, Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo 03828-000, Brazil;
    7 Centro Nacional de Conservação da Flora, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro 22460-030, Brazil;
    8 Royal Botanic Garden Edinburgh, 20 a Inverleith Row, Edinburgh EH3 5LR, UK
    *Author for correspondence. E-mail:luisaazevedomeyer@gmail.com
  • Received:2023-06-30 Accepted:2023-12-11 Online:2024-02-22 Published:2024-03-01

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 data set of 151 sites (4498 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 Caatinga inselbergs and limestone outcrops being the least protected.

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