Flora das cangas de Carajás: taxonomia preparando novos caminhos

Resumo Nas cangas da Floresta Nacional (FLONA) de Carajás e no Parque Nacional dos Campos Ferruginosos (PNCF) foram registradas 856 espécies, distribuídas em 116 famílias de fanerógamas. As famílias mais ricas foram Poaceae (86), Fabaceae (65) e Rubiaceae (46). O hábito herbáceo foi o melhor representado. Dois gêneros, 24 espécies e uma subespécie são apontadas como endêmicas das cangas da área de estudos. Na FLONA de Carajás, a Serra Norte, com maior amostragem, possui 659 espécies de fanerógamas e na Serra Sul foram registradas 545 espécies. Aproximadamente 60% das espécies documentadas na área de estudos, incluindo espécies endêmicas, não possuem registro para o PNCF. Através da lista taxonômica aqui apresentada, foi possível demonstrar considerável distinção entre as cangas da Serra dos Carajás e as do Quadrilátero Ferrífero, em Minas Gerais, apontando também pouca correspondência dessas duas listas com a canga de Corumbá, no Mato Grosso do Sul. A riqueza e singularidade da flora da região, que inclui diversas espécies endêmicas, associada à ameaça a que estão submetidos estes ambientes por atividades de mineração, apontam para a necessidade de um planejamento para conservação das espécies da flora das cangas de Carajás. Abstract The Floresta Nacional de Carajás (FLONA of Carajás) and the Parque Nacional dos Campos Ferruginosos (PNCF) are home to canga vegetation where 856 species distributed in 116 families of seed plants were recorded. The richest families were Poaceae (86), Fabaceae (65) and Rubiaceae (46) and the best represented habit was herbaceous. Two genera, 24 species and one subspecies are considered endemic from the canga of the studied area. Within the FLONA of Carajás, the Serra Norte was the best sampled site, and is home for 659 species of seed plants, while 545 species were recorded for the Serra Sul. Approximately 60% of the species documented, including the endemics, have no record within the PNCF. Through the taxonomic list here presented, it was possible to demonstrate considerable distinction between the canga of the Serra dos Carajás and the same formation in the Quadrilátero Ferrífero, in Minas Gerais, with little correspondence between these two lists and the one from Corumbá, Mato Grosso do Sul state. The richness and singularity of the regional flora, which includes many endemisms, associated to the current threats to these environments due to mineral exploration, point to the need for careful and consistent planning to ensure the conservation of the flora of the canga of Carajás.

Abstract In the state of Pará (Brazil), until the beginning of last decade little was known about the composition of the fern and lycophyte flora. The ferruginous mountains of Carajás are located in Southeastern Pará, mostly inserted in the Floresta Nacional de Carajás. The objective of this work is to present a complete and updated list of fern and lycophyte species occurring in all vegetation types from Carajás ferruginous mountains as a contribution to the knowledge of these plant groups from the Brazilian Amazon. The species list was based on specimens collected between 2007 and 2013. About 1068 specimens deposited in the BHCB Herbarium were studied. A total of 186 species of pteridophytes were recorded, 175 species of ferns distributed in 22 families and 68 genera, and 11 species of lycophytes distributed in three families and four genera. The fern and lycophyte flora of Serra dos Carajás region corresponds to 64% of the Pará state flora of these groups and 34% of the Brazilian Amazon fern and lycophyte flora. Seven taxa are presented as new records for Pará state: Asplenium abscissum, A. otites, A. praemorsum, Blechnum lanceola, Elaphoglossum minutum, Doryopteris collina, and Hemionitis tomentosa. Three species are endemic to Serra dos Carajás, Isoetes cangae, I. serracarajensis, and Selaginella stomatoloma.