Correlates of molt in golden lion tamarins (Leontopithecus rosalia)

In this paper we describe the timing and correlates of molt for a native population of golden lion tamarins (Leontopithecus rosalia). We conducted 820 examinations of 267 adult tamarins over a 7.75 year period to determine the annual molting cycle in this population. Dorsal molt was an annual event for most individuals in the study population; however, 10% of sampled individuals apparently molted twice in a 12 month period. Duration of molt was estimated at 5–6 weeks. The proportion of samples in which tamarins were in molt was significantly greater during the wet season than the dry season and positively correlated with mean monthly precipitation and minimum temperature but not tamarin births, suggesting an environmental component to timing of molt. We found no sex differences in the occurrence of molt during wet or dry seasons. However, the relative frequency of samples in molt was significantly less for gravid females than for nongravid females. In four polygynous groups, socially dominant females gave birth before subordinate females, and younger reproductive females completed molt before older reproductive females. © 1995 Wiley-Liss, Inc.     

Sources of variability in numbers of live births in wild golden lion tamarins (Leontopithecus rosalia)

We examined the effects of several variables on the number of live births in multiparous females in a wild population of golden lion tamarins (Leontopithecus rosalia). Independent variables included the number of infants born to a female the previous breeding season, the number of infants weaned the previous breeding season, the female's age and body mass, the number of adult males and helpers in the group, and the inbreeding coefficient of the offspring. We also tested the hypothesis that trapping and chemical immobilization during pregnancy affected the number of live births. Female body mass was the only statistically significant predictor of the number of live-born infants in the current season when both first and second peaks were included. Characteristics that predicted higher numbers of infants in the first peak of a season were the number of infants born the previous season and the body mass of the female. The greater the number of infants born the previous season, the greater the number of infants born in the first peak of the current season. Factors positively correlated with the number of live births in the second peak within a season included the number of infants born the previous season, as well as the number of available helpers. Due to sample size constraints, the analysis of litters in the second peak did not include body mass of the female as a variable. Inbreeding and handling did not affect the number of live births. We found no evidence that current reproduction negatively impacts future reproduction in this species. We also found no evidence for an age-related reduction in fertility.     

Foraging ecology and use of space in wild golden lion tamarins (Leontopithecus rosalia)

In this paper we describe the use of space and feeding ecology of seven groups of golden lion tamarins observed for a total of 2,164 hr in Poço das Antas Reserve, Rio de Janeiro, Brazil. Relative to habitat availability in the home ranges of these groups, lion tamarins spent more time than expected in relatively undisturbed swamp forests and less time than expected in more degraded hillside and pasture habitats. Home range area was correlated with group biomass but not group size. Golden lion tamarins fed primarily on fruits and small animal prey, but relied heavily on floral nectar during seasonal periods of relatively low fruit availability. Compared to other New World monkeys, lion tamarins used larger home range areas and exhibited longer daily path lengths than would be predicted by group biomass alone. We suggest that this pattern of foraging and use of space may be explained by the relatively greater availability of cryptic prey and their microhabitats in forests that are flooded and/or have closed canopies than in forests that are in earlier stages of succession where prey may be more susceptible to desiccation during the dry season. Am. J. Primatol. 41:289–305, 1997. © 1997 Wiley-Liss, Inc.     

Provisioning in wild golden lion tamarins (Leontopithecus rosalia): benefits to omnivorous young

Provisioning may act to cushion weaned young from dietary insufficiencyand errors during the period in which they are mastering complexforaging techniques or learning to identify appropriate dietaryitems. That is, young mammals who receive food from others maygain nutritional and/or informational benefits. I conducteda longitudinal study of 13 wild golden lion tamarins 11–56weeks of age in six groups to evaluate hypotheses regardingthe functions of provisioning. All members belonging to thisprimate taxonomic family (the Callitrichidae) are cooperativebreeders and are known to provision their young more frequentlythan do other primate species, except humans. My results, togetherwith experimental findings, suggest that juveniles receive bothnutritional and informational benefits from being provisioned.My juvenile study subjects received animal prey (invertebratesand small vertebrates) from others more frequently than plantresources (fruits and hardened exudates). Apparently difficult-to-handlefruits were more likely to be transferred than readily processedfruits. These results support the nutritional benefits hypothesisbecause the young received items, particularly lipid- and protein-richprey, that they might not otherwise have acquired. That juvenilesfed independently on, and were provisioned with, the same fruitson the same day is counterevidence to the nutritional benefitshypothesis, however. The informational benefits hypothesis wassupported because juveniles received a large variety of foods(including more than 20% of fruit species eaten) and receiveduncommon fruits that were easily acquired. Adults emitted food-offeringcalls to encourage the transfer of prey to juveniles, particularlywhen the prey was whole and alive.     

Census and distribution of the golden lion tamarin (Leontopithecus rosalia)

During 1990–1992, a survey of the golden lion tamarin, Leontopithecus rosalia, was carried out throughout its known distribution area. Forest remnants were identified by visual interpretation of Landsat‐TM satellite images. Localities occupied by L. rosalia were first identified by interviews with local people. All forests more than 20 ha in size, and for which two or more interviews suggested the presence of the species, were surveyed using “play‐back” recordings of lion tamarin long calls. The total wild population of L. rosalia, including that of the Poço das Antas Biological Reserve, was estimated to be 562 individuals in 109 groups. The lion tamarins were generally found in four major areas of forest (six or more groups per forest, not including Poço das Antas), with a further 12 groups isolated in small forest patches. Currently the species' distribution is restricted to just four municipalities in the state of Rio de Janeiro: Silva Jardim, Cabo Frio, Saquarema, and Araruama. Although they are typically confined to lowland forest of <300 m altitude, L. rosalia was recorded at an altitude of 550 m in one locality. Average group size varied from 3.6 to 5.7 individuals, and densities from 0.39 groups/km² to 2.35 groups/km² (2.17 individuals/ km² to 8.53 individuals/km²). Six of the isolated groups found during the survey were successfully translocated to a forest of 2,400 ha. There is now also a significant population of reintroduced lion tamarins. Overall, however, the possibilities for further expansion of the wild population are severely limited. Am. J. Primatol. 59:29–44, 2003. © 2003 Wiley‐Liss, Inc.     

Diet, foraging, and use of space in wild golden-headed lion tamarins

Lion tamarins (Callitrichidae: Leontopithecus) are small frugi-faunivores that defend large home ranges. We describe results from the first long-term investigation of wild golden-headed lion tamarins (L. chrysomelas; GHLTs). We present data about activity budgets, daily activity cycles, diet, daily path length, home range size, home range overlap, and territorial encounters for three groups of GHLTs that were studied for 1.5-2.5 years in Una Biological Reserve, Bahia State, Brazil, an area characterized by aseasonal rainfall. We compare our results to those from other studies of lion tamarins to identify factors that may influence foraging and ranging patterns in this genus. Ripe fruit, nectar, insects, and small vertebrates were the primary components of the GHLT diet, and gums were rarely eaten. Fruit comprised the majority of plant feeding bouts, and the GHLTs ate at least 79 different species of plants from 32 families. The most common foraging sites for animal prey were epiphytic bromeliads. The GHLTs defended large home ranges averaging 123 ha, but showed strong affinities for core areas, spending 50% of their time in approximately 11% of their home range. Encounters with neighboring groups averaged two encounters every 9 days, and they were always aggressive. Data about time budgets and daily activity cycles reveal that the GHLTs spent most of their time foraging for resources or traveling between foraging sites distributed throughout their home ranges. The GHLTs spent much less time consuming exudates compared to lion tamarins in more seasonal environments. Additionally, the GHLTs had much larger home ranges than golden lion tamarins (L. rosalia), and did not engage in territorial encounters as frequently as L. rosalia. GHLT ranging patterns appear to be strongly influenced by resource acquisition and, to a lesser extent, by resource defense.     

Influence of rainfall on sleeping site choice by a group of anubis baboons (Papio anubis)

For diurnal nonhuman primates, shifting among different sleeping sites may provide multiple benefits such as better protection from predators, reduced risk of parasitic infection, and closer proximity to spatially and temporally heterogeneous food and water. This last benefit may be particularly important in sleeping site selection by primates living in savanna‐woodlands where rainfall is more limited and more seasonally pronounced than in rainforests. Here, we examined the influence of rainfall, a factor that affects food and water availability, on the use of sleeping sites by anubis baboons (Papio anubis) over two 13‐month study periods that differed in rainfall patterns. We predicted that during wet periods, when food and water availability should be higher, the study group would limit the number of sleeping sites and would stay at each one for more consecutive nights than during dry periods. Conversely, we predicted that during dry periods the group would increase the number of sleeping sites and stay at each one for fewer consecutive nights as they searched more widely for food and water. We also predicted that the group would more often choose sleeping sites closer to the center of the area used during daytime (between 07:00 and 19:00) during wet months than during dry months. Using Global Positioning System data from collared individuals, we found that our first prediction was not supported on either monthly or yearly timescales, although past monthly rainfall predicted the use of the main sleeping site in the second study period. Our second prediction was supported only on a yearly timescale. This study suggests that baboons’ choice of sleeping sites is fluid over time while being sensitive to local environmental conditions, one of which may be rainfall.     

Urinary and plasma gonadotropin concentrations in golden lion tamarins (Leontopithecus r. rosalia)

This paper describes the development and validation of a plasma and urinary gonadotropin immunoassay for golden lion tamarins (Leontopithecus rosalia), an endangered New World callitrichid primate. The assay is derived from a macaque chorionic gonadotropin assay and was validated for both plasma and urine samples in L. rosalia. Levels of immunoreactive LH/CG in lion tamarin urine were highly correlated (r = + 0.98) with gonadotropin bioactivity. Immunoreactive LH/CG levels were examined in two contexts: in the urine of adult females and in the plasma of adult males after administration of estrogen. Peaks of gonadotropin excretion were detected in samples collected from nonpregnant adult females. The peaks occurred immediately prior to cyclic elevations in urinary estrogen excretion. Plasma LH/CG concentration in males measured 24 and 48 hours after a single 50 μg injection of estradiol benzoate were significantly lower than levels at these time points measured after control treatment. Together, the results of this study point to the utility of the gonadotropin assay for monitoring reproductive function in both female and male lion tamarins.     

Selection of river crossing location and sleeping site by proboscis monkeys (Nasalis larvatus) in Sabah, Malaysia

From May 2005-2006, selections of river crossing locations and sleeping sites used by a one-male group (BE-Group) of proboscis monkeys (Nasalis larvatus) were investigated along the Menanggul River, tributary of the Kinabatangan River, Sabah, Malaysia. The frequency of river crossings for focal monkeys in the BE-Group was significantly higher at locations with narrow branch-to-bank distances. Branch-to-bank distances were defined as the distances between the longest tree branches extending over the river and the bank of river on each side. This was measured in areas crossed by the monkeys. The focal monkeys used locations with a higher probability of successful river crossings that did not require jumping into the water and swimming across than those that did. The frequency of sleeping site usage by the BE-Group was positively correlated with the frequency of using river crossing locations by the focal monkeys. Previous reports on predation of proboscis monkeys indicate that clouded leopards (Neofelis diardi) and crocodilians (Tomistoma schlegeli and Crocodylus porosus) may be the major terrestrial and aquatic predators of these monkeys. The selection of river crossing locations by proboscis monkeys may be influenced both by the threat of these predators and the location of suitable and protected sleeping sites. Finally, sleeping sites locations that offer arboreal escape routes may protect proboscis monkeys from leopard attack.     

The fragmented Atlantic rain forest of Brazil: size, shape and distribution of forest fragments

The geographical characteristics of a total of 1839 forest fragments surrounded by sugar cane fields were studied in the Brazilian Atlantic rain forest region of the northeastern state of Pernambuco. The size and shape of the fragments as well as inter-fragment distances and the effects of varying edge width were examined using a geographical information system. The analyses show that the fragments are relatively small and close to each other. Approximately 48% of the rain forest fragments are <10 hectares, while only about 7% are >100 hectares. Forest fragments are close to each other, as fragments located 50m or less apart formed groups that included ca. 50% of the total forest area. At 350m inter-fragment distance, 98% of the rain forest area was included in groups of fragments. Due to the small size and irregular shape of the fragments, the total area of edge zone exceeds that of the interior habitat when the edge width is ca. 60m. At an edge width of 300m ca. 94% of the total fragment area is edge zone. For conservation purposes, ways of establishing networks of forest fragments connected by corridors and stepping stone fragments are demonstrated using GIS. Simulations using these techniques show that reforestation of sugar cane fields between the forest fragments would considerably increase the area of interior forest habitat and connectivity between fragments.     

Mycorrhizal status of some plants of the Araucaria forest and the Atlantic rainforest in Santa Catarina, Brazil

 In Brazil, the Araucaria forest and the Atlantic rainforest are two threatened ecosystems, with 10% or less of their original areas presently existing. To assess the mycorrhizal status in these forests, roots of 29 native species, belonging to 19 families, were collected throughout the year from different regions of Santa Catarina, Brazil. Roots were washed, and then cut in a cryo-microtome to seek ectomycorrhizal colonization. Other roots were stained before being examined for vesicular-arbuscular mycorrhizas (VAM). Patterns of colonization were identified and photographed. All plants presented evidence of vesicular-arbuscular mycorrhizal colonization. No evidence of ectomycorrhizal colonization was found. Vesicular-arbuscular mycorrhizal colonization patterns varied from single intracellular aseptate hyphae, coils, and/or appressoria, to vesicles and/or arbuscules. Results confirmed that VAM hosts are predominant in South American forests while ectomycorrhizas are extremely rare even among genera known as ectomycorrhizal in other regions of the humid tropics. Accepted: 27 August 2000     

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.     

Effect of selective logging on forest structure and nutrient cycling in a seasonally dry Brazilian Atlantic forest

Aim The Brazilian Atlantic forest covers c. 10% of its original extent, and some areas are still being logged. Although several ecological studies in Atlantic forest have been published over the past two to three decades, there has been little research on forest dynamics and there is a particular lack of information on the effects of disturbance. The aim of the present study was to assess the impact of selective logging on forest structure, floristic composition soil nutrients, litterfall and litter layer in a seasonally dry Atlantic forest. Location The Mata do Carvão is located in the Guaxindiba Ecological Reserve in São Francisco do ltabapoana district (21°24′ S, 41°04′ W), Rio de Janeiro, Brazil. Methods Four plots (50 × 50 m) were set up in 1995 in each of two stands: unlogged and logged. In each plot, all trees ≥ 10 cm d.b.h. were enumerated, identified and measured. Vouchers were lodged at UENF Herbarium. Five surface soil samples were collected in each plot in the dry season (in October 1995). Litterfall was collected in eight traps (0.50 m²) in each plot over a year from 14 November 1995 to 11 November 1996. The litter layer was sampled in eight quadrats (0.25 m²) in each plot in the dry and wet seasons. Soils were air‐dried, sieved, and chemically analysed. The litter was dried (80 °C), sorted into six fractions, weighed and bulked samples analysed for nutrients. Results Forest stands did not differ in stem density and total basal area, with a total of 1137 individuals sampled in 1996 (564 unlogged and 573 logged), and a total basal area of 15 m² (unlogged) and 13.0 m² (logged). However, unlogged stands had more large trees (≥ 30 cm in d.b.h.) and greater mean canopy height. Among the families, Rutaceae and Leguminosae were the most abundant families in both sites, although the Rutaceae had a higher density in unlogged and Leguminosae in the logged stand. The species diversity index was similar between stands. Late‐successional species, such as Metrodorea nigra var. brevifolia and Paratecoma peroba, were less abundant in the logged stand. Selective logging did not affect nutrient concentrations in the soil or in the litter. However, quantities of the nutrients in the total litterfall and in the leaf litterfall and litter layer were higher in unlogged than in logged stands, mainly as a result of fallen M. nigra leaves. Metrodorea nigra was considered a key species in the nutrients dynamics in Carvão forest. Main conclusions Despite the fact that effects on tree diversity and soil nutrients were not clear, selective logging in this Atlantic forest altered canopy structure, increased the relative abundance of some early‐secondary species and decreased the litter input and stock of nutrients. Detailed information on the influence of logging on the distribution and structure of plant populations and in nutrient processes is fundamental for a sustainable logging system to be developed.     

Tropical forest loss drives divergent patterns in functional diversity of forest and non-forest birds

Tropical forests have been facing high rates of deforestation driven by multiple anthropogenic disturbances, with severe consequences for biodiversity. However, the understanding of such effects on functional diversity is still limited in tropical regions, especially considering different ecological groups responses. Here, we evaluated the functional responses of birds to forest loss at the threatened Brazilian Atlantic forest, considering the complete assemblage, and both forest-dependent and non-forest-dependent species. Birds were surveyed in 40 forest sites with a forest cover gradient, located in two regions showing different land use types. We tested different models to assess the responses of functional diversity indices to forest loss in these sites. Although functional diversity did not differ between regions, forest and non-forest birds showed divergent responses to forest loss. Deforested landscapes presented an increase in functional richness (SESFRic) and evenness for forest species and an increase of functional dispersion for non-forest birds. Additionally, forested landscapes harbor birds presenting lower body mass and wing length, and non-forest species with lower tarsus length. The maintenance of some functional metrics through forest loss resulted from a compensatory dynamic between forest and non-forest birds, indicating that only evaluating the complete assemblage may mask important idiosyncratic patterns of different ecological groups. Although non-forest species are relatively capable to maintain bird functional diversity in deforested landscapes, forest birds are facing a drastic ongoing collapse in these sites, representing an alarming signal for the maintenance of forest ecosystem function.