Do the seasonal forests in northeastern Brazil represent a single floristic unit?

Floristic analyses (Principal Component Analysis and Analysis of Group Indicators) at the genus level were employed to characterize and compare seasonal forest formations in northeastern Brazil. The presence--absence of 248 genera of woody plants occurring in 24 floristic surveys was correlated with geomorphology and climatic variables. The analyses were consistent and point to the existence of two floristic groups of seasonal forests in the region, one more closely related to the Atlantic Coastal Forest (mata atlântica) and the other to the xerophytic formations (caatinga) of the region. The driest seasonal forest group experiences more than 8 dry months per year and/or a total annual rainfall of <1000 mm, and is found on the ancient eroded peaks in the semi-arid core and on the western slopes of the Borborema Plateau.

Do the seasonal forests in northeastern Brazil represent a single floristic unit? / As florestas estacionais do nordeste brasileiro representam uma única unidade florística?

Floristic analyses (Principal Component Analysis and Analysis of Group Indicators) at the genus level were employed to characterize and compare seasonal forest formations in northeastern Brazil. The presence - absence of 248 genera of woody plants occurring in 24 floristic surveys was correlated with geomorphology and climatic variables. The analyses were consistent and point to the existence of two floristic groups of seasonal forests in the region, one more closely related to the Atlantic Coastal Forest (mata atlântica) and the other to the xerophytic formations (caatinga) of the region. The driest seasonal forest group experiences more than 8 dry months per year and/or a total annual rainfall of <1000 mm, and is found on the ancient eroded peaks in the semi-arid core and on the western slopes of the Borborema Plateau.

Análises florísticas no nível genérico (análise de componentes principais e análise de grupos indicadores) foram realizadas com o objetivo de caracterizar e comparar as formações florestais estacionais do Nordeste oriental brasileiro. A presença - ausência de 248 gêneros de plantas lenhosas presentes em 24 levantamentos florísticos foi correlacionada com a geomorfologia e variáveis climáticas. As análises foram consistentes e apontaram a existência de dois grupos florísticos de florestas estacionais, um mais relacionado às florestas litorâneas (mata atlântica) e outro às formações xerofíticas (caatinga). O grupo das florestas estacionais mais secas sofre pelo menos oito meses de seca por ano e recebe no máximo 1000 mm per year de precipitação, sendo estas encontradas sobre os picos elevados da região semi-árida e na encosta ocidental do planalto da Borborema.

The arboreal component of a dry forest in Northeastern Brazil.

The dry forests of northeastern Brazil are found near the coastal zone and on low, isolated mountains inland amid semi-arid vegetation. The floristic composition of these dry montane forests, as well as their relationship to humid forests (Atlantic forest sensu stricto) and to the deciduous thorn woodlands (Caatinga sensu stricto) of the Brazilian northeast are not yet well known. This paper sought to determine if the arboreal plants in a dry forest growing on a low mountain in the semi-arid inland region (Serra Negra, 8 degrees 35 - 8 degrees 38 S and 38 degrees 02 - 38 degrees 04 W) between the municipalities of Floresta and Inajá, state of Pernambuco have the same floristic composition and structure as that seen in other regional forests. In fifty 10 x 20 m plots all live and standing dead trees with trunk measuring > 5 cm diameter at breast height were measured. Floristic similarities between the forest studied and other regional forests were assessed using multivariate analysis. The results demonstrate that the dry forest studied can be classified into two groups that represent two major vegetational transitions: (1) a humid forest/dry forest transition; and (2) a deciduous thorn-woodland/ dry forest transition.

The arboreal component of a dry forest in Northeastern Brazil

As florestas secas do Nordeste do Brasil são encontradas próximo à zona costeira, nos planaltos e em montanhas baixas e isoladas no interior do semi-árido nordestino. A composição dessas florestas secas e sua relação com as florestas úmidas (Floresta Atlântica sensu stricto) e a vegetação arbustivo-arbórea caducifólia espinhosa (Caatinga sensu stricto) do Nordeste do Brasil ainda não estão resolvidas. Este trabalho procura determinar se a flora arbórea da floresta seca que cresce em uma montanha baixa da região semi-árida localizada entre os municípios de Floresta e Inajá, Pernambuco (Serra Negra, 8° 35’ - 8° 38’ S e 38° 02’ - 38° 04’ W) apresenta a mesma composição florística e estrutura observada em outras florestas da região. Foram amostrados todos os indivíduos vivos ou mortos, ainda de pé, com diâmetro do tronco à altura do peito > 5 cm, presentes em 50 parcelas (10 x 20 m). A similaridade florística entre Serra Negra e outras florestas da região foram avaliadas usando análises multivariadas. Os resultados demonstram que as florestas secas englobam dois conjuntos florísticos que representam duas transições: (1) transição florestas úmidas/ florestas secas; e (2) transição vegetação arbustivo-arbórea caducifólia espinhosa/floresta seca, onde está localizada Serra Negra.