Francisca Maria Barbosa

Levantamento florístico do componente arbustivo-arbóreo da vegetação ciliar na bacia do rio Taperoá, PB, Brasil

Considerando o papel relevante e o nivel de degradacao presente nas areas ciliares, a pesquisa objetivou estudar a composicao floristica do componente arbustivo-arboreo da vegetacao ciliar em diferentes ambientes hidricos do semi-arido paraibano na bacia do rio Taperoa. O levantamento floristico foi realizado no periodo de junho/2002 a fevereiro/2003 e abrangeu nove pontos distribuidos ao longo de rios, riachos, lagoa e acude. A definicao das atividades apoiou-se em analise de cartas e mapas da vegetacao em escala de 1:100.000 e caminhadas aleatorias que permitiram a realizacao de coleta de material vegetal, utilizado para identificacao por meio de consultas a especialistas e de morfologia comparada, usando bibliografia especializada e analise das exsicatas depositadas no herbario Lauro Pires Xavier - JPB (UFPB, Joao Pessoa, PB). A vegetacao arbustivo-arborea da mata ciliar nos nove pontos amostrados foi representada por 43 especies, das quais 41 sao pertencentes a 19 familias, e duas especies permaneceram indeterminadas. As familias que apresentaram o maior numero de especies foram Mimosaceae (sete), Caesalpiniaceae (cinco) e Euphorbiaceae (cinco). Os resultados da analise de agrupamento indicaram que as areas ciliares apresentaram certa particularizacao em termos de composicao floristica, o que se refletiu nos baixos indices de similaridades entre o conjunto de areas amostradas.

Population Dynamics of Croton blanchetianus Baill. in a Caatinga Area in the Brazilian Semi-Arid

The vegetation of the Caatinga, present in the dry areas of the Brazilian Semi-arid region has been little studied, when it relates to population dynamics of their species. The objective of this study was to evaluate the mortality and recruitment rates of a Croton blanchetianus Baill. population in a two-year interval (January/2013 to January/2015), in area of caatinga in the semi-arid Paraiba. Monitoring of structural changes in the vegetation was carried out in 96 10 × 10 m contiguous plots. The phytosociological survey conducted in January 2013 sampled 1078 individuals of C. blanchetianus, occurring in the 96 plots studied. The years of 2012 and 2013 had rainfall below the annual average. Take into consideration the evaluation period; there was a high mortality rate (M = 47.33% year-1) and a low recruitment rate (R = 0.18% year-1) for the population of C. blanchetianus. The real gain (RG) of the population was significantly negative (-93.91% year-1) since the number of dead individuals was much higher than the recruited ones in the population. The highest height class, composed of individuals of 4.1 to 5.0 m height, was the most tolerant to water scarcity, resulting in 53.85% of surviving individuals. Therefore, the results demonstrated that periodic droughts compromise the recruitment, development, survival, and establishment of individuals in natural systems in the Brazilian semi-arid region.

Hydrothermal treatments for overcoming dormancy in seeds of Mimosa ophthalmocentra Mart. ex Benth. (Fabaceae: Mimosoideae)

The efficiency in the production of seedlings is decisive for the final result of their applicability. Therefore, strategies to ensure a rapid and uniform emergence are necessary, especially when it is associated with sustainable methods. The aim of this study was to evaluate the influence of different water temperatures as overcoming seed dormancy in Mimosa ophthalmocentra Mart. ex Benth., simply and economically, in the Brazilian Semiarid Region. The experimental design was completely randomized with four replications, each one consisting of 50 seeds, which were subjected to six treatments: intact seeds (T1/control) and seeds immersed in water at 55, 65, 75, 85, and 95 °C (T2, T3, T4, T5, and T6, respectively). Sowing was performed in trays under environmental conditions and evaluations were performed daily for 28 days. The emergence percentage, emergence speed index (ESI), and length and dry mass of seedlings were evaluated. Data were subjected to analysis of variance, and the means were compared by Tukey test (p < 0.05). M. ophthalmocentra has tegumentary dormancy, and its emergence was influenced by water temperature. Immersion of seeds in water at 75 oC for 1 min provided the best result with 60% of emergence, ESI of 2.68, and seedlings with longer lengths and higher dry mass.

STUDY OF THE SHRUB-TREE LAYER OF RIPARIAN FORESTS IN THE BASIN OF THE TAPEROÁ RIVER, IN THE SEMI-ARID REGION OF PARAÍBA: A PERSPECTIVE ON THE SUSTAINABILITY OF NATURAL RESOURCES.

STUDY OF THE SHRUB-TREE LAYER OF RIPARIAN FORESTS IN THE BASIN OF THE TAPEROÁ RIVER, IN THE SEMI-ARID REGION OF PARAÍBA: A PERSPECTIVE ON THE SUSTAINABILITY OF NATURAL RESOURCES. A floristic survey of the shrub-tree layer of riparian forests in the basin of the Taperoá River in the semi-arid region of Paraíba was carried out. Seven sampling sites were distributed along rivers and streams based on the analysis of charts and vegetation maps at the scale 1:100.000. Non-systematic botanical collections were done monthly from June 2002 to September 2005 and the plants were identified by botanical experts or by comparisons with material deposited in the Lauro Pires Xavier Herbarium (JPB). The shrub-tree layer presented 63 species in 52 genera and 26 families. The families with the highest number of species were: Mimosaceae (nine), Euphorbiaceae (seven), Caesalpiniaceae (six) and Fabaceae (six).