Atlantic Forest Reserve Research Articles

Diet of the Neotropical Otter, Lontra longicaudis, in an Atlantic Forest Area, Santa Catarina State, Southern Brazil

The diet of the neotropical otter (Carnivora, Mustelidae) was studied from September 1995 to March 1997, in Volta Velha, an Atlantic Forest reserve in the coastal plain of Santa Catarina State, southern Brazil. Fecal samples were collected monthly along the rivers Saí-Mirim, Braço do Norte and Volta Velha. Additionally, from October 1996 to June 1997, a qualitative and quantitative study of fish species available in the studied rivers was performed. The analysis of 202 collected fecal samples indicated a diet based on fish (mainly Hoplias malabaricus and Geophagus brasiliensis) and crustaceans (mainly Trichodactylus fluviatilis, a river crab), characterizing the neotropical otter as piscivorous-cancrivorous in the study area. The presence of fruits, reptiles, birds and mammals in the diet is occasional and opportunistic. Probably the higher consumption of a certain fish species compared to its availability and the high percentage of occurrence of T. fluviatilis in scats of the neotropical otter reflect their higher catchability.

The Phlebotominae sand fly (Diptera: Psychodidae) fauna of two Atlantic Rain Forest Reserves in the State of Rio de Janeiro, Brazil.

During two consecutive years, studies on the sand fly fauna in Poço das Antas and Fazenda Bom Retiro, two Atlantic Rain Forest Reserves from the State of Rio de Janeiro, were performed using Shannon traps, CDC light traps and human bait collections. Eleven species were identified; Lutzomyia longipalpis, L. migonei, L. edwardsi, L. intermedia, L. whitmani, L. fischeri, L. shannoni, L. ayrozai, L. hirsuta, L. monticola and L. misionensis (first occurrence in the State of Rio de Janeiro). L. intermedia and L. whitmani were the predominant anthropophilic species around houses, while L. hirsuta predominated in the forest.

Bird diversity and abundance in forest fragments and Eucalyptus plantations around an Atlantic forest reserve, Brazil

Little of Brazil's remaining Atlantic forest is protected, so it is important to assess how well the region's wildlife can persist in areas/habitats outside reserves. We studied bird diversity and abundance during 546 point counts in the Sooretama/Linhares reserve, 200 point counts in 31 forest fragments (10- 150 h), and 50 point counts in <30-year-old Eucalyptus plantations, within 7 km of the reserve. Only eight bird species were recorded in Eucalyptus, and this impoverishment, as compared to some Eucalyptus plantations elsewhere in Brazil may be a result of intensive clearance of understory vegetation. Species diversity in forest fragments was significantly lower than in the reserve. Twelve, mostly non-forest or edge species, were significantly commoner in the fragments, but nineteen species were frequent in the reserve but rare or absent in forest fragments. These included two Pyrrhura parakeets, a Brotogeris parakeet, a trogon Trogon, a jacamar Galbula, woodpeckers Piculus and Campephilus, Myrmotherula antwrens, and Hemithraupus and Tachyphonus tanagers. Bird species richness at points in forest fragments did not decline with fragment size, distance from the reserve, or forest quality. However, forest in fragments was more heavily degraded than forest within the reserve and poor forest quality may be the cause of declines in some species. Whilst protection of forest within reserves is a priority, management of forest fragments may aid conservation of some threatened species.

Density and Population Size of Mammals in Remnants of Brazilian Atlantic Forest.

From October 1994 to April 1996, I surveyed six 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 openface> 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/km2 ) significantly lower than that of large fragments (20.9 individuals/km2 ). 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 <100 individuals per species in the small reserves. The estimates provided here indicate that only Atlantic forest reserves of ≥20,000 ha can sustain viable populations ( Ne ≅ 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.

Borrelia-like spirochetes recovered from ticks and small mammals collected in the Atlantic Forest Reserve, Cotia county, State of São Paulo, Brazil.

Forty-four marsupials, 77 rodents and 161 ticks were captured in an Atlantic Forest Reserve in Cotia county, State of São Paulo, where human cases of Lyme disease (LD) simile were reported. Twenty-one borrelia-like spirochete isolates were recovered from the mammals' blood and rodent livers or spleens, and triturated ticks inoculated into BSK II medium. Our results suggest that the reservoirs and ticks collected may harbor borrelia-like spirochetes, some of which have an antigenic similarity with the unknown causative agent of LD simile in Brazil, and/or with North American Borrelia burgdorferi s. s.

Parrot populations and habitat use in and around two lowland Atlantic forest reserves, Brazil

We estimated population sizes of parrots in a large (Sooretama/Linhares) and a small (Porto Seguro) lowland Atlantic forest reserve, and examined their habitat associations within the reserves, and their use of forest fragments. In Sooretama, most species had estimated populations between 1000 and 20,000 individuals, but in the smaller reserve population densities were low and all but one species had population estimates <500. Two Amazons, including the ‘Endangered’ Amazona rhodocorytha, were strongly linked to primary forests whereas the ‘Vulnerable’ Pyrrhura cruentata was associated with non-pristine forest. There was considerable movement of parrots between the Sooretama reserve and the surrounding country with Amazona species tending to fly into the reserve during the mornings, and the macaw Propyrrhura maracana flying out. Other species, notably P. cruentata and P. leucotis, were never recorded away from the reserve. Most parrot populations in the region are likely to be small, and the substantial populations around Sooretama make this reserve a parrot stronghold. It is crucial that fire, illegal logging and parrot capture are adequately controlled within Sooretama, and there is a strong argument for extending conservation management efforts to areas immediately outside the reserve.

Effects of fragmentation of the Atlantic forest on mammal communities in south-eastern Brazil

Six Atlantic forest reserves, two large (c. 20,000 ha each), two medium-sized (c. 2,000 ha each) and two small (c. 200 ha each), located in northern Espı́rito Santo, south-eastern Brazil were censused for mammals from October 1994 to April 1996. Diurnal and nocturnal line-transect sampling was used for censusing mammals>1 kg body weight, and the relative abundance of species in the six fragments was compared. The number of mammal species recorded in the reserves was strongly related to the forest area, the richest community being recorded in the two large reserves and the poorest in the two small reserves. The large reserves had a structurally more complex community, with top predators, large, terrestrial frugivores and large myrmecophages. The mammal community of the small and the medium-sized reserves was impoverished and less complex. Frugivores were numerically predominant in both large and medium-sized reserves, whereas herbivores dominated the mammal community of the small reserves, mainly through the absence of agoutis Dasyprocta leporina and the high density of maned sloth Bradypus torquatus in the two small reserves. The lack of predators and the proliferation of secondary vegetation and lianas throughout the small reserves are probably the main causes for the success of arboreal folivores there. Illegal hunting was found to reduce the encounter rates of mostly large, terrestrial frugivores such as agoutis, pacas Agouti paca, peccaries Pecari tajacu and Tayassu pecari and deer Mazama spp., and is contributing to keep the population of the surviving species low.

Activity budgets and ranging patterns of the Atlantic forest maned sloth Bradypus torquatus (Xenarthra: Bradypodidae)

AbstractThree maned sloths were observed for a total of 680 h throughout 14 months in an Atlantic forest reserve of south‐eastern Brazil. The study animals were located in the forest, monthly by radio‐telemetry, and data on daily activity budgets were collected recording the actual time they spent in major activities. Individual home ranges were very small (0.5–6 ha, depending on the method used) and the sloths travelled an average of only 24 m during the 24 h period. A comparison between day‐ and night‐range lengths suggests that maned sloths ranged more during daytime (17 m) than at night (5 m), indicating a predominantly diurnal period of activity. They rested, on average, for 74% of daytime, but a substantial variation was found between individuals (range 60–80%). Although a lack of synchrony was observed in activity pattern between study animals monitored simultaneously, all three sloths tended to start feeding and moving at the same time of the day (07:00–08:00), and the time that elapsed between the start of these activities on consecutive days was about 24 h, indicating a circadian rhythm of activity for the species. This finding contradicts previous studies on congeneric sloths, in which suggestions that Bradypus does not show cyclic patterns of activity were based on qualitative rather than quantitative data. Given the species' highly folivorous diet and the characteristic low basal rate of metabolism in this genus, the rather high levels of activity and the predominantly diurnal period of activity observed for maned sloths are probably related to the lower ambient temperatures found in the Atlantic forest when compared to other more equatorial localities of the Neotropics. Further studies with additional sloths are necessary, however, to ascertain the validity of this conclusion.

Diet of the Atlantic forest maned sloth Bradypus torquatus (Xenarthra: Bradypodidae)

The diet of maned sloths was studied throughout 14 months in an Atlantic forest reserve of south-eastern Brazil. Three adult sloths were observed for a total of 680 h and located monthly by radio-telemetry. Data were collected on diet, recording the actual time the sloths spent eating plant species. Overall, the diet was composed of 99% leaves, with young leaves (68%) preferred to mature ones (7%) throughout the year. A higher proportion of tree leaves (83%) than liana leaves (16%) were included in the diet. When analysed together, the diet of the three animals included a total of 21 plant species (16 tree and 5 liana), but each individual made up its diet with an even smaller number of species (7–12) and with a particular subset of the local flora. This is a very small portion of the total number of tree and liana species available to the sloths; furthermore, the top species consumed were present at very low population densities in the forest. Thus, B. torquatus, like other congeneric species studied elsewhere in the Neotropics, is a strictly arboreal folivore with a highly selective diet, probably resulting from evolving physiological adaptations to cope with a smaller range of plant secondary compounds. This is possible for the species of this genus through a combination of low basal rates of metabolism, which enable the sloths to survive on an energy-poor diet, and a very long passage time of digesta, which, in turn, aids the digestion of a fibre-rich diet while possibly contributing to the degradation of secondary compounds.

Activity budgets and ranging patterns of the Atlantic forest maned sloth Bradypus torquatus (Xenarthra: Bradypodidae)

Three maned sloths were observed for a total of 680 h throughout 14 months in an Atlantic forest reserve of south-eastern Brazil. The study animals were located in the forest, monthly by radio-telemetry, and data on daily activity budgets were collected recording the actual time they spent in major activities. Individual home ranges were very small (0.5–6 ha, depending on the method used) and the sloths travelled an average of only 24 m during the 24 h period. A comparison between day- and night-range lengths suggests that maned sloths ranged more during daytime (17 m) than at night (5 m), indicating a predominantly diurnal period of activity. They rested, on average, for 74% of daytime, but a substantial variation was found between individuals (range 60–80%). Although a lack of synchrony was observed in activity pattern between study animals monitored simultaneously, all three sloths tended to start feeding and moving at the same time of the day (07:00–08:00), and the time that elapsed between the start of these activities on consecutive days was about 24 h, indicating a circadian rhythm of activity for the species. This finding contradicts previous studies on congeneric sloths, in which suggestions that Bradypus does not show cyclic patterns of activity were based on qualitative rather than quantitative data. Given the species' highly folivorous diet and the characteristic low basal rate of metabolism in this genus, the rather high levels of activity and the predominantly diurnal period of activity observed for maned sloths are probably related to the lower ambient temperatures found in the Atlantic forest when compared to other more equatorial localities of the Neotropics. Further studies with additional sloths are necessary, however, to ascertain the validity of this conclusion.

Diet of the Atlantic forest maned sloth Bradypus torquatus (Xenarthra: Bradypodidae)

AbstractThe diet of maned sloths was studied throughout 14 months in an Atlantic forest reserve of south‐eastern Brazil. Three adult sloths were observed for a total of 680 h and located monthly by radio‐telemetry. Data were collected on diet, recording the actual time the sloths spent eating plant species. Overall, the diet was composed of 99% leaves, with young leaves (68%) preferred to mature ones (7%) throughout the year. A higher proportion of tree leaves (83%) than liana leaves (16%) were included in the diet. When analysed together, the diet of the three animals included a total of 21 plant species (16 tree and 5 liana), but each individual made up its diet with an even smaller number of species (7–12) and with a particular subset of the local flora. This is a very small portion of the total number of tree and liana species available to the sloths; furthermore, the top species consumed were present at very low population densities in the forest. Thus, B. torquatus, like other congeneric species studied elsewhere in the Neotropics, is a strictly arboreal folivore with a highly selective diet, probably resulting from evolving physiological adaptations to cope with a smaller range of plant secondary compounds. This is possible for the species of this genus through a combination of low basal rates of metabolism, which enable the sloths to survive on an energy‐poor diet, and a very long passage time of digesta, which, in turn, aids the digestion of a fibre‐rich diet while possibly contributing to the degradation of secondary compounds.

Diet and vertical space use of three sympatric opossums in a Brazilian Atlantic forest reserve

Few studies have investigated the ecological relationships between marsupials or their importance in community composition (Dickman 1984). The small size, nocturnal activity and arboreal habits of many species of didelphid marsupials present some difficulties in studying them. Vertical space use of vertebrates in tropical forests is difficult to examine, especially because of canopy height and great habitat complexity (sensu August 1983). However, this latter factor has a considerable importance in spatial separation of sympatric species, amplifying the possibilities of resource partitioning (Giller 1984). Previous studies on vertical space use of didelphid marsupials showed the importance of vertical stratification for this group (Charles-Dominique et al. 1981, Julien-Laferriere 1991, Malcolm 1991, Stallings 1989). Miles et al. (1981) stated that ecological segregation of Neotropical marsupials is not obviously determined by the species' diets, but is better related to spatial differentiation, which discards competition for food. However, these authors recognize the necessity to study the interactions between diet and space use for the comprehension of resource partitioning strategies. The purpose of this study was to examine the food habits and vertical space use in sympatric species of opossums in the Atlantic forest of Brazil. We hypo-

Grooming in brown howler monkeys, Alouatta fusca.

The grooming behavior of a group of brown howler monkeys was studied for one year in an Atlantic forest reserve of southeastern Brazil. A total of 290 grooming bouts were recorded and analyzed. The two adult females directed most of the grooming (91%), while the adult male was the major recipient (37%). Grooming between females, and between them and their siblings, also occurred quite often. On average, the group spent 2% of its daily time grooming, with a higher frequency around noon. There were significant differences, however, in time spent grooming between seasons; grooming was more abundant during the coldest seasons (autumn-winter) and rarer in hotter ones (spring-summer). A significant negative correlation was found between grooming time and temperature, but contrary to expectations, grooming time failed to correlate with both the group' diet and the demands of food-gathering, as measured by travelling time and day range length. A comparison of grooming behavior with other species of the genus suggests that brown, red (A. seniculus), and black howler monkeys (A. caraya) are more similar to each other than to mantled howlers (A. palliata), a result that probably is linked with the differing social structure and group size of the latter species. © 1995 Wiley-Liss, Inc.