996 resultados para Forest remnant


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In the Atlantic Montane Rain Forest of south-eastern Brazil, a field study was carried out to describe the forest disturbance regime, analyse canopy gap composition and evaluate the influence of habitat parameters on gap tree species composition. We characterized canopy gaps considering the group of variables as follows: area, type and number of tree/branch falls, topographic position, soil coverage and surrounding canopy trees. Gap composition was assessed at species level by measuring all individuals inside gaps higher than one meter. Mean gap area of the 42 canopy gaps analysed was 71.9 +/- 9.0 m(2) (mean +/- SE). Out of the studied gaps, 35.7% were created by uprooted and by snapped trees, 16.7% by dead-standing trees and 11.9% by the fall of large branches. The disturbance regime was characterized by gap openings predominantly smaller than 150 m(2) and by spatial patterning related to topography. Ridges had smaller gaps and higher proportions of gaps created by branch falls; slopes had bigger gaps generally created by uprooting events. The more abundant and frequent species were shade tolerant and the more species-rich families found inside gaps did not differ from the forest as a whole. Pioneer species were rare and restricted to medium and large size classes. The Indicator Species Analysis and the Canonical Correspondence Analysis indicated gap area, topography and the percentage of soil cover by the genera Calathea and Ctenanthe were the predominant variables correlated with woody species distribution. So, topography emerged as an important issue not only to the gap disturbance regime, but also to gap colonization. In respect to the influence of gap processes on the Atlantic Montane Rain Forest regeneration, our results support the view that canopy gap events may not be working as promoters of community wide floristic shifts.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The feeding ecology of the Atlantic forest marmosets (Callithrix spp.) in southeastern Brazil is poorly known, and few studies have focused on buffy tufted-eared marmosets, Callithrix aurita. We determined the food items and investigated the seasonal variation in the diet of a group of four Callithrix aurita in a 17-ha semideciduous forest fragment in southern Minas Gerais State, Brazil. We recorded daily feeding activities between October 1994 and September 1995 using scan sampling at 5-min intervals. The marmosets devoted feeding rime to gums (50.5%), fruits (11%), and animal prey (38.5%) in a fetal of 499 records. Plant resources comprised 27 species from 16 families. They used Acacia paniculata (Mimosoideae, Leguminosae), the main gum source (82%), year-round Maclura tinctoria (Moraceae) was the fruit species that they consumed most (22%). The marmosets preyed on caterpillars (33%), katydids (5%), and homopterans (4%). Feeding on fruits varied seasonally and was inversely related to gum feeding. Consumption of animal prey remained constant over the year. The wide and year-round dependence on gum suggests that Acacia may play a critical role in marmoset persistence in forest fragments.

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Two new species of brachycephalid frogs are described from Pico Marumbi, municipality of Morretes, and Pico da Igreja, municipality of Guaratuba, Parana State, southern Brazil. The new species share the following attributes: body bufoniform; skin on top of the head, and central part of the back body smooth with no dermal co-ossification; outer metatarsal tubercle distinct; dermal roofing bones of skull unornamented; all paired cranial bones distinct and not fused; quadratojugals, and maxillary odontoids present. The new species from Pico Marumbi is characterized by male SVL = 11.6-12.5 and female SVL = 13.0-14.5 turn; and general color orange with dorsal reddish-brown irregular markings, lateral surfaces with small dark brown spots, and belly with brownish spots and small dots. The new species from Pico da Igreja is characterized by male SVL = 12.6-13.9 and female SVL = 14.6-15.3 mm; and general color orange, lateral surfaces with small dark brown spots, and belly with brownish coalescent spots and small dots. Comparisons with other brachycephalid species and osteological data are provided.

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The present study was conducted in the Serra do Japi in the State of São Paulo, Brazil. From March 2004 to January 2006 we studied the ecology and reproductive biology of two sympatric species of Aplastodiscus in three different habitats: lake, stream, and swamp. The majority of A. leucopygius males in calling activity were recorded during the rainy season and during sporadic rains in the dry season (April to September). The same was observed for A. arildae. Most courtship displays of A. leucopygius were observed mainly during the rainy period and only one courtship behaviour was observed for A. arildae during a rainy night, in December 2005. Aplastodiscus leucopygius males were found in activity in the three habitats surveyed. In contrast, males of A. arildae were found in only one habitat (stream). Spatial distribution seems to be the main mechanism of reproductive segregation between the studied species.

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No presente estudo foi realizado um inventário das espécies de anfíbios anuros que ocorrem em um fragmento de mata ciliar do Córrego do Espraiado, localizado na Universidade Federal de São Carlos (UFSCar), Município de São Carlos, estado de São Paulo, sudeste do Brasil. Durante os meses de março de 2009 a fevereiro de 2010 foram realizadas saídas de campo semanais nas quais foram registradas 13 espécies de anuros. A atividade reprodutiva das espécies de anuros componentes da comunidade estudada mostrou-se sazonal, sendo que houve correlação positiva e significativa entre o número de espécies em atividade reprodutiva e o fotoperíodo. Verificamos que a comunidade estudada mostrou-se mais semelhante a comunidades de anuros de florestas de transição entre Mata Atlântica e Cerrado do que a fragmentos de Cerrado próximos da região.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)