Vol.:(0123456789) 1 3 Brazilian Journal of Botany https://doi.org/10.1007/s40415-020-00608-5 ORIGINAL ARTICLE Plant species on Amazonian canga habitats of Serra Arqueada: the contribution of an isolated outcrop to the floristic knowledge of the Carajás region, Pará, Brazil Taiana Laura da Fonseca‑da‑Silva 1,2,3  · Juliana Lovo 2,3  · Daniela C. Zappi 2,3  · Marcelo F. Moro 4  · Eduardo da Silva Leal 1  · Clóvis Maurity 2  · Pedro L. Viana 3 Received: 13 July 2019 / Revised: 2 April 2020 / Accepted: 2 May 2020 © Botanical Society of Sao Paulo 2020 Abstract The Serra Arqueada, in the municipalities of Ourilândia do Norte and São Félix do Xingu, in southeastern Pará state, Brazil, has an extension of c. 50 km and reaches altitudes between 450 and 689 m above sea level. This range harbours outcrops of campo rupestre on canga, an iron-rich substrate, which were not studied in the Flora of the canga of the Serra de Carajás (FCC) project. We present here the first botanical survey of this site, with the main objective to document its plant diversity. We also aim to improve our knowledge of species distribution, biogeographical relationships and conservation of the canga within the Carajás Mineral Province. Our results indicate the occurrence of 153 angiosperm species representing 53 families. This study also reveals the occurrence of two species previously not reported for Pará: Scaphyglottis livida (Orchidaceae) and Rhynchospora exilis (Cyperaceae). We compare the floristic composition of canga areas from Serra Arqueada with similar sites from the Serra dos Carajás and find Serra Arqueada safeguards at least eight edaphic endemic species from the canga of the FCC region. Moreover, there is a high number of microhabitats in the area, which is probably related to the relative distinct and diverse flora. These data highlight the importance of conversation in the area, safeguarding these species and microhabitats. We conclude Serra Arqueada represents an appropriate site for conservation purposes. Keywords Amazonia · Campo rupestre · Conservation · Floresta Nacional de Carajás · Parque Nacional dos Campos Ferruginosos Resumo A Serra Arqueada, situada em Ourilândia do Norte e São Félix do Xingu, no sudeste do Pará, Brasil, possui uma extensão de c. 50 km e altitudes entre 450 e 689 m acima do nível do mar. Esta serra apresenta, nas suas porções mais altas, áreas de campo rupestre sobre canga, que não foram incluídas no projeto Flora das cangas das Serras dos Carajás (FCC). Apresenta- mos a primeira lista de angiospermas destes afloramentos, com o principal objetivo de documentar sua diversidade vegetal. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s40415-020-00608-5) contains supplementary material, which is available to authorized users. * Juliana Lovo lovo.juliana@gmail.com 1 Universidade Federal Rural da Amazônia, Capanema, Pará CEP68700-030, Brazil 2 Biodiversity and Ecosytem Services Team, Instituto Tecnológico Vale, Belém, Pará CEP 66055-090, Brazil 3 Museu Paraense Emílio Goeldi, Belém, Pará CEP 66077-830, Brazil 4 Instituto de Ciências do Mar (Labomar), Universidade Federal do Ceará, Fortaleza, Brazil