Fig 1.
Map of study sites in Eastern Brazil and Amazonian Carajás (CRJ) showing canga (red) and quartzite (blue) sites.
Carajás sites are magnified to show Serra Norte (SN1-8), Serra Sul (S11A-D), Serra do Tarzan (ST) and Serra da Bocaina (SB). Brazilian Biomes are Amazon Rainforest (pale green), Cerrado (pale yellow), Caatinga (pale orange) and Atlantic Rainforest (lilac).
Fig 2.
A-D: Amazonian canga in Pará, Brazil; A. Aerial view of the Lagoa das Três Irmãs, Serra Sul, FLONA Carajás showing dense forest reaching the edge of the open vegetation; B. Temporary lagoon at the Serra da Bocaina, Parque Nacional dos Campos Ferruginosos; C-D. Serra Sul landscape during the dry (C) and rainy season (D). E. Eastern Brazil canga at the Serra do Capanema, Minas Gerais. F-H: Eastern Brazilian campo rupestre on quartzitic substrate; F. Serra do Ibitipoca, Minas Gerais; G. Diamantina plateau in Minas Gerais; H. Serra do Barbado, near Catolés, Chapada Diamantina, Bahia. (Photos A-D João Marcos Rosa, E-H PLV).
Fig 3.
A. Critically Endangered Xyris platystachya (Xyridaceae) from the Serra do Cipó, Minas Gerais; B. Paepalanthus eriophaeus (Eriocaulaceae) collected at the Serra do Cipó, Minas Gerais; C. Sporobolus multiramosus (Poaceae), a rare species from the Amazonian canga in Carajás, Pará; D. Spigelia sellowiana (Loganiaceae) in Minas Gerais; E. Borreria elaiosulcata (Rubiaceae), restricted to the Amazonian canga in Carajás, Pará; F. Endangered Physocalyx scaberrimus (Orobanchaceae) from the Serra do Cipó, Minas Gerais; G. Buchnera carajasensis (Orobanchaceae), endemic to the Amazonian canga in and around Carajás, Pará; H. Vanhouttea hilariana (Gesneriaceae), from the southernmost quartzitic campo rupestre of Minas Gerais. (Photos A, C, E, G, H PLV, B DCZ, D William Milliken, F Leandro Freitas).
Fig 4.
The campo rupestre megatree indicating substrate affinities for 4705 species; The outer ring (blue only) represents quartzite in Bahia, middle ring both quartzite (blue) and canga (red) in Minas Gerais and inner ring (red only) the Amazonian canga.
Plant groups mentioned in the results and discussion are highlighted.
Fig 5.
Floristic relationships between the 28 sites analysed including the canga of Amazonian Carajás, canga of Minas Gerais and quartzite in Minas Gerais and Bahia represented by (a) NMDS using Bray-Curtis distance. Ellipses show 95% confidence limits for delimitation of each group. Final stress for two dimensions: 0.0657927; (b) UPGMA using Bray-Curtis distance showing the floristic relationships between the 28 sites analysed representing the canga of Amazonian Carajás, canga of Minas Gerais and quartzite of Minas Gerais and Bahia. For abbreviations see Fig 1 caption.
Fig 6.
Six examples of differential representations showing contrasting over-represented clades in the quartzitic, canga or mixed areas.
(a) Xyridaceae to Cyperaceae in quartzite versus Poaceae in canga; (b) Loganiaceae to Apocynaceae in quartzite versus Rubiaceae in canga; (c) Lamids in the Amazon × Campanulids in Eastern Brazil; (d) Family Nyctaginaceae, genus Guapira in the Amazon × Neea in Eastern Brazil; (e) Asparagales in the Atlantic Rainforest × Commelinids elsewhere; (f) Plantaginaceae to Orobanchaceae in campo rupestre × Gesneriaceae in the Atlantic Raiforest. SOS = specific overrepresentation score.
Fig 7.
(a) NMDS ordination using Bray-Curtis distance for the individual mountaintops in Amazonian Carajás. Total stress = 0.1439546. Ellipses show 95% confidence limits for delimitation of each group; (b) UPGMA grouping using Bray-Curtis distance of individual mountaintops in Amazonian Carajás. For abbreviations see caption of Fig 1.
Fig 8.
Diagram of sites grouped during the analysis, showing total species richness for merged groups of sites (r), number of combined sites (n) for each group and relative numbers of species shared between groups.
From top right: Amazonian canga (red), Bahia (blue), Minas Gerais quartzite (blue), Minas Gerais, canga and quartzite (lilac) and Minas Gerais canga (red).