Marcelo Henrique Ongaro Pinheiro

Spatial-temporal distribution of fire-protected savanna physiognomies in Southeastern Brazil

The analysis of the influence of edaphic finer textures, as a facilitating factor for the expansion of forest formations in the absence of fire, was possible thanks to rare characteristics found in a savanna fragment located in the State of São Paulo, Brazil. The total suppression of fire for over four decades, and the occurrence of two savanna physiognomies, cerrado sensu stricto and cerradão, allowed the conduction of this study based on the hypothesis that cerradão, a physiognomy of forest aspect consisting of fire-sensitive tree and shrubs species, is favored by fire absence and higher soil hydric retention capacity. Edaphic samples were collected from a regular grid of 200 m(2) for the production of isopletic maps of the distribution of clay, fine sand, coarse sand and silt edaphic textures by the geostatistic method of ordinary kriging. Changes in the areas occupied by both savanna physiognomies, defined on the basis of aerial photographs taken over a period of 43 years, were assessed through mean variation rates. Besides corroborating the hypothesis of edaphic hydric retention as a facilitating factor for the expansion of forest physiognomies in savanna areas, we were able to infer the positive influence of higher precipitation on the increase in cerradão expansion rates.

Florística de uma Floresta Estacional Semidecidual, localizada em ecótono savânico-florestal, no município de Bauru, SP, Brasil

Informacoes floristicas escassas, referentes ao municipio de Bauru, e a elaboracao de hipoteses sobre mecanismos de ocupacao de fitocenoses florestais por especies savânicas, representaram as principais questoes motivadoras do presente estudo, desenvolvido em dois fragmentos de floresta estacional semidecidual (5 ha e 7 ha) mantidos pelo Jardim Botânico de Bauru, que abriga tambem savana florestada. O material botânico foi coletado a partir de caminhadas ao acaso e em parcelas implantadas durante estudo fitossociologico. Foram encontradas 264 especies arbustivo-arboreas, pertencentes a 58 familias. Dessas especies 126 foram coletadas apenas na fitocenose florestal, e 66 especies foram coletadas em ambas as fitocenoses. As duas familias com o maior numero de especies foram Rubiaceae (25 especies) e Myrtaceae (21 especies). Foi realizada analise de similaridade floristica, a partir do indice de Jaccard (SJ), entre a floresta do JBMB e outros 11 remanescentes florestais, alguns dos quais, sob influencia floristica savânica. A riqueza floristica dos fragmentos florestais do JBMB sofreu incremento, pela ocupacao de especies savânicas, oriundas da savana florestada contigua. Incendios preteritos, alem da ocorrencia de microambientes distintos, representaram provaveis fatores de facilitacao para a invasao dessas especies savânicas.

Cucurbitaceae, Gurania Cogn., for southern Amazonia, Mato Grosso, Brazil

We found six species of the genus Gurania that are described here as new records for the state of Mato Grosso, Central Brazil. The species of Gurania recorded here occur in the north of Mato Grosso state, Brazil in the biome recognized as “ Floresta Amazonica ”. This is an area of southern Amazonia that has been poorly inventoried. We carried out the surveys in permanent plots using the RAPELD-PPBio system and along trails giving access to the permanent plots.