Comunidade de mamiferos não-voadores de um fragmento de floresta Atlantica semidecidua do municipio de Campinas, SP

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The population richness, composition, abundance and density of non-volant mammals of mata Ribeirão Cachoeira forest, a 230 ha semideciduous forest fragment in the outskirts of Campinas, São Paulo, were studied between 2001 and 2003. The main objective was to evaluate the importance of this forest fragment to the local and regional conservation of the native mammals. The small mammals were trapped over 17 months using live-traps on the ground, understory and canopy. Population numbers were estimated using mark and recapture techniques. I deployed 9,884 night-traps with a recapture success of 15.2%. A total 555 individuals were marked which resulted in 1506 recaptures. The small mammal community comprised of 10 species, three marsupials, the mouse opossum Gracilinanus microtarsus, the large opossums, Caluromys philander and Didelphis aurita, and seven rodents, the rice-rat, Oligoryzomys nigripes, the grass mouse, Akodon montensis, two arboreal rats, Rhiphidomys mastacalis e Oecomys sp, the black rat, Rattus rattus, the water rat, Nectomys squamipes, and the squirrel, Sciurus aestuans. The marsupials had the largest biomass, mainly comprised of the large opossum Didelphis aurita. Rodents had the largest relative abundance which Oligoryzomys nigripes presented in the largest number of captures. The largest population density was observed in Gracilinanus microtarsus, Oligoryzomys nigripes and Akodon montensis. The marsupials had a marked seasonal breeding period, starting in the transition between dry and wet season. The rodents bred over the whole study period but increased in the transition between dry and wet season as well. There were more males than females in Gracilinanus microtarsus. Males showed signs of senescence after breeding and they were not recaptured in the second year of this study. This suggests that they are semelparous, similar to other Neotropical and Australian marsupials. Large and midsize mammals were studied using visual census over 12 months in linear transects during the day, totaled 271 km. Direct observation, camera traps and indirect signs such as footprints, droppings, tree and ground scratches, vocal display and interviews with local residents were used to indicate their presence. A total of 152 direct observations were recorded. Footprints were surveyed in sand plots over two to five consecutive night periods. Odour bait was used in 1,258 plot-nights and banana bait was used in 1,073 plot-nights. Camera traps monitored 8,076 hours, 5,628 hours in the dry (rate of 2.1 pictures/ 100 h), and 2,448 hours in the wet season (rate of 1.4 pictures/100 h). A total of 23 species of large and midsize mammals were recorded using all sampling methods. Eleven species of carnivores: crab-eating fox, Cerdocyon thous; maned wolf, Chrysocyon brachyurus; puma, Puma concolor; ocelot, Leopardus pardalis; jaguarundi, Herpailurus yaguaroundi; margay, Leopardus wieddi; tayra, Eira barbara; river otter, Lontra longicaudis; grison, Galictis cuja; crab-eating racoon, Procyon cancrivorous; and coati, Nasua nasua. Four species of primates: white-tufted-ear marmoset, Callithrix jacchus, a non-native to the region; titi monkey, Callicebus nigrifrons; capuchin monkey, Cebus nigritus, and brown howler monkey, Alouatta guariba. Four species of rodents: capybara, Hydrochaeris hydrochaeris; paca, Agouti paca, porcupine, Coendou villosus, and squirrel, Sciurus aestuans. One artiodactyl, deer, Mazama sp; one xenarthran, nine-banded armadillo, Dasypus novemcinctus, and one lagomorph, brazilian rabbit, Sylvilagus brasiliensis. Domestic dogs, Canis familiaris, were frequent in the forest and they were recorded in all methods. Howler monkeys were the most common mammals (103 observations) in the visual transects. Their density was of 37.1 individuals/km2 with an average group size of 3.51 individuals. Opossums (60%) and crab-eating fox (20%) had the highest presence recorded in the footprints. Banana baits attracted the largest number of species. Herbivore-omnivorous species were significantly more present in the banana baits while carnivorous were more present in the odour baits. Carnivore-frugivores had similar frequency of presence in both baits. Twelve species were photographed with the camera traps. Carnivores had the highest number of records. Two young and one adult of pumas were photographed three times over a 16-month period. The nine-banded armadillo had the highest number of records (27%, 0.51 pictures/100 h). The Ribeirão Cachoeira forest fragment showed high diversity of small, midsize and large mammals. Eight species are threatened and three are probably threatened of extinction in the São Paulo state. This study revealed the biological value and importance of this forest fragment which highlights the need for actions to ensure its biological viability in a medium term. The implementation of wildlife corridors, by gallery forests restoration, to network Ribeirão Cachoeira with other similar forest fragments will guarantee the genetic diversity and hopefully it will decrease the risk of extinction of local populations

ASSUNTO(S)

mamiferos comunidades animais população - biologia

ACESSO AO ARTIGO

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