Seed predation and seed dispersal are key factors that determine plant recruitment. In this study, we compared the role of small (\200 g) and 'large' mammals as predators of Araucaria angustifolia (Araucariaceae) seeds in the Brazilian Araucaria Forest. We also investigated the effect of deposition site, namely open grassland, forest edge or forest interior ([50 m from the edge) on seed-removal rates. We conducted field experiments on seed removal in July 2003 and 2004. We compared the habitat types using two exclusion treatments: semipermeable exclosure (exclusive access of small rodents) and an open control (access of all mammal groups). We considered proportion of seeds removed after 15 days to investigate the effect of year, habitat type, and exclusion treatment on seed removal by using three-factor permutational ANOVA. We also evaluated seed fate and seed consumers by using spool-and-line devices attached to seeds and camera trapping. The results showed that seed removal differed significantly between years and among habitat types, but not between exclusion treatments. Removal rates were higher in 2004 than in 2003 and also were significantly lower in the open field when compared with both forested types (edge or interior) in both years. There was also a significant interaction between 'year' and 'habitat' which was driven by an increase in 2004 removal rates in the open field compared to the previous year. Our combination of manipulative experiments, camera-trapping survey, and spool-and-line seed tracking demonstrated that small rodents are responsible for the majority of seed removal of A. angustifolia in the study area. The low removal rates in open habitats indicate that they could serve as safe sites for A. angustifolia seeds. The results also suggested a potential role of small rodents as seed dispersers (about 4% of removed seeds were not consumed). The knowledge of how fragmentation affects pattern of seed predation and establishment of A. angustifolia through changes in abundance of different-sized mammals is essential for the conservation of the Brazilian Araucaria Forest and its most characteristic species.
Studies on patterns of habitat use by mammals are necessary for understanding the mechanisms involved in their distribution and abundance. In this study, we used the spool-and-line method to investigate habitat utilization by two sigmodontine rodents from Brazilian Cerrado, Necromys lasiurus and Oryzomys scotti. We conducted the study in a Cerrado area in central Brazil (15156 0 S and e 47156 0 W) where the animals were caught in an area of 7.68 ha of Cerrado sensu stricto. Captured individuals were marked, equipped with a spool-and-line device, and released at the same capture point. The next day we followed the thread to record their daily movements and find their nests. To investigate microhabitat selection we compared habitat characteristics along trails of each studied species with general habitat characteristics of the study area. Although the mean 24-h distance was greater for N. lasiurus (mean 7 SE: 41.9 7 42.2 m, N=3) than for O. scotti (28.7 7 14.2 m, N=6) this difference was not significant (Mann-Whitney test, U=26, P40.6). We detected significant differences among observed microhabitats variables of both species and available microhabitat characteristics as determined by discriminant analysis (Wilks 0 s lambda F=3.001; df=14, 116; Po0.001). Both species were associated to microhabitat characteristics whose values differed markedly from the overall available habitat. Along the first canonical discriminant function of the DFA both them were associated with greater grass height than the mean height available and along the second axis N. lasiurus selected areas with higher fruit availability and more shelters than those selected by O. scotti. For stronger inferences regarding differential patterns of habitat utilization by Cerrado rodents we suggest the simultaneous use of both spool-and-line and standard trapping methods.
ABSTRACT. Despite its wide range and abundance on certain habitats, the crab-eating raccoon Procyon cancrivorus (G. Cuvier, 1798) is considered one of the less known Neotropical carnivore species. In the present study we analyzed the diet of P. cancrivorus in a peat forest and in an estuarine island in southernmost Brazil. Fruits of the gerivá palm tree Syagrus romanzoffiana were the most consumed item in the peat forest, followed by insects and mollusks. Small mammals, followed by Bromelia antiacantha (Bromeliaceae) fruits and brachyuran crustaceans were the most frequent items in the estuarine island. Other items found in lower frequencies were Solanum sp., Psidium sp., Smilax sp. and Dyospiros sp. fruits, diplopods, scorpions, fishes, anuran amphibians, reptiles (black tegu lizard and snakes), birds and medium-sized mammals (white-eared opossum, armadillo and coypu). Levin's index values (peat forest: 0.38; estuarine island: 0.45) indicate an approximation to a median position between a specialist and a well distributed diet. Pianka's index (0.80) showed a considerable diet similarity between the two systems. Procyon cancrivorus presented a varied diet in the studied areas and may play an important role as seed disperser on coastal environments in southernmost Brazil. KEYWORDS.Bromelia antiacantha, crab-eating racoon, feeding habits, subtropical Brazil, Syagrus romanzoffiana. RESUMO. Dieta de Procyon cancrivorus (Carnivora, Procyonidae) em ambientes de restinga e estuarino no Sul do Brasil. Apesar de sua ampla distribuição e abundância em determinados habitats, o mão-pelada Procyon cancrivorus (G. Cuvier, 1798) é considerado uma das menos conhecidas espécies de carnívoro Neotropical. No presente estudo analisamos a dieta de P. cancrivorus em uma mata paludosa e uma ilha estuarina no extremo sul do Brasil. Frutos da palmeira gerivá Syagrus romanzoffiana foi o item mais consumido na mata paludosa, seguido por insetos e moluscos. Pequenos mamíferos, seguidos por frutos de Bromelia antiacantha (Bromeliaceae) e crustáceos braquiúros foram os itens mais frequentes na ilha estuarina. Outros itens encontrados em menor frequência foram frutos de Solanum sp., Psidium sp., Smilax sp. and Dyospiros sp., diplópodos, escorpiões, peixes, anfíbios anuros, répteis (teiú e serpentes), aves e mamíferos de médio porte (gambá-da-orelha-branca, tatu e ratão-do-banhado). Os valores do índice de Levin (mata paludosa: 0.38; ilha estuarina: 0.45) indicam uma aproximação a uma posição mediana entre uma dieta especialista e bem distribuída. O índice de Pianka (0.80) mostrou uma considerável similaridade na dieta entre os dois sistemas. Procyon cancrivorus apresentou uma dieta variada nas áreas estudadas e pode desempenhar um importante papel como dispersor de sementes em ecossistemas costeiros no extremo sul do Brasil.
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