Although highly diverse (Fonseca et al. 1996), the Atlantic forest mammal fauna is still poorly known, with very few sites exhaustively inventoried or subjected to long-term studies (Passamani et al. 2000). Although the first surveys using camera traps were carried out in the 1920s (e.g. Chapman 1927), most studies are rather recent (Karanth & Nichols 1998). This is not different in Brazil, where few studies have been published (Marques & Ramos 2001, Santos-Filho & Silva 2002, Silveira et al. 2003, Trolle 2003, Trolle & Kéry 2003). Given this, the objective of this paper is to assess the efficiency of camera trapping as an inventory technique for Neotropical forests in general and Atlantic forest in particular. The study was conducted at the Santa Lúcia Biological Station (SLBS), a biologically rich Atlantic Forest preserve located in south-eastern Brazil (Mendes & Padovan 2000) where mammals have been intensively live-trapped, observed from line-transects or had indirect evidence of their presence (faeces, footprints, scratches, etc.) recorded in earlier years (Passamani et al. 2000).
From October 1994 to April 1996 Atlantic forest reserves, two large (approximately 20,000 ha each), two medium-sized (approximately 2000 ha each), and two small (approximately 200 ha each), located in northern Espírito Santo, southeastern Brazil, for mammals of Ͼ 1 kg body weight. My main objective was to assess the effects of fragmentation on population sizes and densities of five abundant species of forest-dwelling species (three primates and two rodents). I used line-transect sampling to survey mammals and estimated densities through the DISTANCE program. The average density of mammals increased from small to medium to large fragments, with small fragments having an average mammal density (7.6 individuals/km 2 ) significantly lower than that of large fragments (20.9 individuals/km 2 ). This trend was not significant when species that were extinct or absent in some fragments were excluded from the analysis. Shortage of food ( fruits) and predation by small cats ( Leopardus sp.) are the likely factors contributing to the demise of mammals, most of which are frugivores, in small fragments. Estimates of population sizes were on the order of several hundred to thousands of individuals for the large reserves, whereas comparable estimates for the other areas indicate a few hundred individuals for the medium-sized reserves and Ͻ 100 individuals per species in the small reserves. The estimates provided here indicate that only Atlantic forest reserves of Ն 20,000 ha can sustain viable populations ( N e Х 500 individuals) of the five species studied, which represent only about 14% of all medium-sized to large species of mammals known to be present in fragments of this size. Given that only about 20% of all protected areas remaining in the Atlantic forest are equal to or larger than this size, management measures are badly needed to improve mammal conservation in this biome. Densidad y Tamaño Poblacional de Mamíferos en Remanentes del Bosque del Atlántico BrasileñoResumen: Entre los meses de octubre de 1994 a abril de 1996, estudié los mamíferos mayores de un kg de peso en seis reservas forestales, dos grandes ( c. 20,000 ha cada una), dos de tamaño mediano ( c. 2000 ha cada una) y dos pequeñas ( c. 200 ha cada una), localizadas al sureste de Brasil, en la provincia de Espírito Santo. El principal objetivo fue evaluar los efectos de la fragmentación en los tamaños poblacionales y las densidades de cinco especies abundantes residentes del bosque (tres primates y dos roedores). Utilicé muestreos de transectos en línea para evaluar los mamíferos y estimé las densidades mediante el programa DISTANCE. La densidad promedio de los mamíferos incrementó de los fragmentos pequeños a los medianos, a los grandes. Los fragmentos pequeños tuvieron una densidad promedio (7.6 individuos/km 2 ) significativamente menor que la de los fragmentos grandes (20.9 individuos/km 2 ). Esta tendencia no fue significativa cuando las especies extintas o ausentes de algunos fragmentos fueron excluidas del análisis. La escasez de alimento ( frutas) y ...
Cocoa (Theobroma cacao) is cultivated in the states of Bahia and Espírito Santo in easternBrazil under the so-called 'cabruca system', where the understorey of native Atlantic forest is cleared and the canopy is thinned out to provide adequate shading for the cocoa trees. Apart from its economic and social role, the cabruca system is said to be important for the conservation of Atlantic forest biodiversity. In this paper we studied tree species richness and forest structure of cabrucas to examine the demographic health of these forests and discuss their long-term survival. Data were collected in 20 farms located alongside a 30 km track of the northern margin of the Rio Doce, in northern Espírito Santo. All trees !5 cm DBH were identified and their diameter was measured in 80 plots (600 m 2 ), totalling 4.8 ha of sampled area. Recorded trees were also allocated to four different regeneration phases (pioneers, early secondary, late secondary and climax). The inventory resulted in 507 trees belonging to 105 species in 39 families. This species richness is much lower than in less disturbed forests located in the region. Pioneers and early secondary species dominate the cabruca forest in terms of number of species (56.2%), density (71.0%) and basal area (72.3%). The distribution of diameter frequency showed an imbalance in tree regeneration. Most trees in the range of 5-30 cm DBH were pioneers (40.7%), or early secondary species (32.6%), while late secondary and climax trees were less frequent (10.2 and 16.5% of the sampled trees, respectively). The dominance of species of early regeneration phases was also observed for trees >30 cm DBH (69.0% of pioneers or early secondary and 31.0% of late secondary or climax species). The results indicated that the cabruca forests are not only less diverse and less dense than secondary or primary forests of the region, but also, and more importantly, their natural succession and gap dynamics are being severely impaired. As a consequence, cabrucas present a structure where tree species of late successional phases are becoming increasingly rare while pioneers and early secondary species are becoming dominant. If current management practices of thinning and clearing of native trees are not improved, the long-term survival of these forests is questionable and their role in maintaining biodiversity in the long run is limited.
BackgroundSloths are slow-moving arboreal mammals inhabiting tropical rainforests in Central and South America. The six living species of sloths are occasionally reported to display a greenish discoloration of their pelage. Trichophilus welckeri, a green algal species first described more than a century ago, is widely believed to discolor the animals fur and provide the sloth with effective camouflage. However, this phenomenon has not been explored in any detail and there is little evidence to substantiate this widely held opinion.ResultsHere we investigate the genetic diversity of the eukaryotic community present in fur of all six extant species of sloth. Analysis of 71 sloth hair samples yielding 426 partial 18S rRNA gene sequences demonstrates a diverse eukaryotic microbial assemblage. Phylogenetic analysis reveals that sloth fur hosts a number of green algal species and suggests that acquisition of these organisms from the surrounding rainforest plays an important role in the discoloration of sloth fur. However, an alga corresponding to the morphological description of Trichophilus welckeri was found to be frequent and abundant on sloth fur. Phylogenetic analysis demonstrated the retention of this alga on the fur of sloths independent of geographic location.ConclusionsThese results demonstrate a unique diverse microbial eukaryotic community in the fur of sloths from Central and South America. Our analysis streghtens the case for symbiosis between sloths and Trichophilus welckeri.
Presence of exotic species in forest remnants is a major concern for the conservation of wild species, not only on islands, where potential impact is higher. Although the problem is widespread and increasing, there are few studies on Neotropical forests. Here we quantify the occurrence of domestic dogs (Canis lupus familiaris) in an Atlantic forest reserve in south-eastern Brazil (Santa Lúcia Biological Station -SLBS). Throughout two years of monitoring with camera traps (2,142 camera-days), 25 records of 16 individual dogs were obtained in the interior of SLBS, making dogs the fourth most frequently recorded species of mammals in general and the first-ranking among Carnivora, ahead of the ocelot and puma, the top two terrestrial predators present in SLBS. Dogs entered the forest year round, in almost half of the sampled months (48%), and predominantly during daytime (89%). They were detected in various trails inside the reserve, but mostly in areas nearest to the reserve's border (<200 m from the edge). Record rates of domestic dogs did not correlate significantly with climate variables, with frequency of mammal records and richness in general, or with any particular mammal species (Spearman rank correlation, p > 0.05 in all cases), suggesting an erratic, nonseasonal pattern of entrance in the reserve. Data indicate that domestic dogs can be abundant and frequent visitors to little disturbed Atlantic forest reserves even when these are located in regions of low density of human population. The potential impact to native fauna is discussed.Keywords: Atlantic forest, camera traps, Canis lupus familiaris, domestic dogs, exotic species.Cães-domésticos em remanescentes de Mata Atlântica no sudeste do Brasil: padrões de entrada e de ocupação obtidos a partir de armadilhas fotográficas Resumo A presença de espécies exóticas em remanescentes florestais é um dos maiores problemas para a conservação de táxons silvestres, não apenas em ilhas, onde o impacto potencial do contato entre os grupos citados revela-se mais significativo. Apesar deste problema ser amplo e crescente, poucos são os estudos desenvolvidos em florestas Neotropicais. Neste sentido, o presente estudo objetivou caracterizar a presença de cães-domésticos (Canis lupus familiaris) em uma reserva de Mata Atlântica localizada no Sudeste do Brasil (Estação Biológica de Santa Lúcia -EBSL). A partir de dois anos de monitoramento com armadilhas fotográficas (2.142 câmeras-dia), foram obtidos 25 registros de 16 indivíduos no interior da EBSL. Com relação ao número de registros obtidos, o cão-doméstico foi a quarta espécie mais registrada, considerando a mastofauna de maneira geral, e a primeira entre os Carnivora, estando à frente da jaguatirica e da onça-parda, os dois principais predadores terrestres presentes na EBSL. Os cães-domésticos entraram na reserva durante todo o ano, apresentando registros em quase metade dos meses de amostragem (48%), predominantemente ao longo do dia (89%). Os espécimes foram detectados em várias trilhas no interior da EBSL, ...
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