Orchidaceae em afloramentos rochosos do estado de Pernambuco, Brasil

Abstract

ResumoEm Pernambuco, além da Floresta Atlântica costeira, e dos Brejos de Altitude, as encostas orientais do Planalto da Borborema também são regiões ricas em espécies de Orchidaceae. Os afloramentos rochosos são comuns e têm sido indicados com uma das áreas mais representativas para a família no Nordeste do Brasil. O presente trabalho teve como objetivo inventariar a flora de orquídeas da área. Excursões foram realizadas entre 2005 e 2013, contemplando afloramentos rochosos de 13 áreas. Foram encontradas 29 spp. pertencentes a 18 gêneros, sendo Habenaria (seis spp.) e Epidendrum (quatro spp.) os mais representativos. Entre as espécies catalogadas destacam-se Acianthera prolifera e Octomeria alexandri como novos registros para Pernambuco, e Phragmipedium sargentianum que consta na lista de espécies ameaçadas de extinção no Brasil. As espécies são amplamente distribuídas a restritas na sua distribuição, dentre as quais, nove são endêmicas do Brasil. Este estudo corrobora informações anteriores sobre a elevada riqueza e abundância de Orchidaceae nas formações vegetais dos afloramentos rochosos, incluindo muitas espécies endêmicas. Apesar disto, poucas unidades de conservação no estado de Pernambuco englobam esse ecossistema tão importante. Palavras-chave: Caatinga, ecossistemas montanhosos, flora, Floresta Atlântica, inselbergs. AbstractBesides the Atlantic Coastal Forest and the Brejos de Altitude in the state of Pernambuco, the eastern slopes of the Borborema plateau are also rich in species of Orchidaceae. Rocky outcrops are common and have been cited as one of the most representative sites for the family in Northeast Brazil. This study did a survey of the orchid flora on rocky outcrops in this state. Fieldwork was conducted from 2005 to 2013, and rocky outcrops from 13 different areas were visited. A total of 29 species and 18 genera were found. Habenaria (6 spp.) and Epidendrum (4 spp.) are the most representative genera. Of species recorded here, Acianthera prolifera and Octomeria alexandri are highlighted as new records for Pernambuco, and also Phragmipedium sargentianum which is on Brazil's endangered species list. The species are either widely distributed or have a restricted distribution; nine of these species are endemic to Brazil. This study confirms previous data on the great diversity and abundance of Orchidaceae in rocky habitats, including several endemic species. However, very few conservation units in Northeast Brazil contain this important ecosystem.

Floristic composition of a Neotropical inselberg from Espírito Santo state, Brazil: an important area for conservation

“…Esgario et al (2009) also found a great richness of Orchidaceae for montane inselbergs in the midwest of ES. Orchidaceae family represents one of the principal floristic elements of inselbergs of northeastern Brazil, with high levels of endemism (Porembski et al1998;França et al 2006;Gomes & Alves 2010;Pessoa & Alves 2014). In both areas, the montane or cloud inselbergs, a favorable environmental factor, such as presence of continuous or intermittent clouds, responsible for horizontal precipitation, seems to be the main reason for this richness, as observed for other groups of xeric environments such as vascular epiphytes (Nieder et al 2001).…”

Floristic and ecological characterization of habitat types on an inselberg in Minas Gerais, southeastern Brazil

“…Additionally, this is valid not just for endemics, but also for species with broad distributions, since currently they are not found in the matrix, but instead on inselbergs (Pessoa & Alves 2014). In some regions, such as northeastern Minas Gerais, these rock outcrops harbor the last remnants of forest fragments.…”

Climbers from two rock outcrops in the semi-arid region of Brazil

“…According to Martinelli (2007), rock outcrops act as floristic refugia for widely distributed species that do not occur in the areas of surrounding vegetation, as observed by Pessoa and Alves (2014) with Orchidaceae. Most species identified in this study (regardless of being exclusive or common among areas) have a wide distribution among the 3 phytogeographic domains of northeastern Brazil (Caatinga, Cerrado and Atlantic Forest) but grow in areas of rock outcrops and the surrounding vegetation.…”

“…The physiognomy of the vegetation on both rock outcrops is predominantly shrubby herbaceous with spaced trees, forming clumps of different shapes and sizes separated by bare rock (Figs 1-3, 4, 5). These areas were selected for sampling, because studies with other plants groups (Silva et al 2014, Pessoa andAlves 2014) showed high richness and the need to inventory other groups, especially angiosperms.…”