As florestas montanas da Reserva Florestal do Morro Grande, Cotia (São Paulo, Brasil) / The montane forests of the Morro Grande Forest Reserve, Cotia (São Paulo State, Brazil)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The Morro Grande Forest Reserve is located in the municipality of Cotia, state of São Paulo, Brazil, in the Ibiúna Plateau, on the borders of the Paulistano Plateau (ca. 23o35 -50 S and 46o50 - 47ºWG). The Reserve protects an area of 10,000 ha of forest formed by patches of varying successional stages, in an altitude that ranges between 850-1.050 masl. The Reserve is also an important water source for the city of São Paulo. Most of the region is on crystalline basement, with per-Cambrian schist and gneisses. The Reserve is in the ocean-continent climatic transition, in the borders of the tertiary basin of São Paulo, and the local climate is temperate with less dry winter (Cfb, Köppen). According to some authors the region was originally occupied by mixed Atlantic Forest with Araucaria angustifolia. Other authors consider the region part of a seasonal semi deciduous forest complex. This study had the main objective of characterizing the Reserve and the regional forests. Specific objectives were: i) study the tree species composition; ii) compare the old-growth forest patches with successional patches; iii) study late successional stages and characteristic species of different stages; iii) work as a basis for comparison with smaller forest fragments in the region; iv) discuss the importance of the Reserve as a preservation area. Sampling was done using the quadrant method. Two thousands and four hundred trees were sampled in six different sites. In each site four hundred trees were sampled in four blocks of 25 quadrant points or one hundred trees, with 200 m from neighboring blocks. Three sites were located in second growth forest patches while three were located in mature patches. The vegetation was then mapped howing the different successional patches. Results showed differences in sites and blocks, related to human past disturbances. Two hundred and sixty species were found, twelve of them in all six sites. The forest was found to be very species rich. Shannon index (H ) for the different sites was ound to be among the highest for the forest of the state: 4,75 nats/ind. for the Reserve; 4,25 for the hree second growth sites; and 4,54 for the mature sites. Stratified sampling showed the diversity within the forest, showing differences in richness and abundance between sites and blocks, and pecially showing the difference between second growth and mature sites, highlighted by grouping analyses and ordination. A DCA showed the characteristic species within the successional gradient. The forest can be considered as Ombrophyllous Dense Montane Forest, with some species from mixed and seasonal semi deciduous forests and cerradão, which suggests the region as an old high montane refuge under a past drier climate, as well as an ecotone character. The species diversity and the mixture of species of different forest types show the importance of the conservation of the Reserve. This work contributes to the understanding of the regional flora and to biodiversity conservation, to the development of a management plan for the Reserve, and to the understanding of the phytogeographic and ecologic aspects of the Ibiúna and Paulistano Plateaus

ASSUNTO(S)

species richness mata atlantica fitogeografia - são paulo (estado) diversidade biologica - são paulo (estado) phytogeography areas protegidas protected areas biological diversity mata atlantica (brazil)

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