Extinction of a West African Red Colobus Monkey

Abstract: We provide the first documented case of the extinction in the twentieth century of a widely recognized primate taxon. During surveys in Ghana and Côte d'Ivoire in 1993–1999, we were unable to find any surviving populations of Miss Waldron's red colobus monkey (   Procolobus badius waldroni ), a primate taxon endemic to the forests of this part of West Africa. We conclude that this monkey, which at least one authority considers worthy of species status, is probably extinct. Hunting by humans appears to be the ultimate cause of the extinction. Until our surveys began, little attention had been paid to the plight of this red colobus monkey, despite its listing as endangered by the World Conservation Union. The extinction of other large animals in the Upper Guinea rainforest region is likely to follow soon unless more attention is paid to the full range of endangered forms and more resources are devoted to their rigorous protection.     

Effects of anthropogenic disturbance on primate density at the landscape scale

Accurate estimations of the abundance of threatened animal populations are required for assessment of species’ status and vulnerability and conservation planning. However, density estimation is usually difficult and resource demanding, so researchers often collect data at local scales. However, anthropogenic pressures most often have landscape-level effects, for example, through habitat loss and fragmentation. We applied hierarchical distance sampling (HDS) to transect count data to determine the effect of habitat and anthropogenic factors on the density of 3 arboreal primate species inhabiting 5 distinct tropical forests across a landscape of 19,000 km² in the Udzungwa Mountains of Tanzania. We developed a novel, multiregion extension of HDS that allowed us to model density and detectability jointly across forests without losing site-specific information. For all species, the effect of anthropogenic disturbance on density was overwhelmingly negative among metapopulations: −0.63 Angolan colobus (Colobus angolensis palliatus) (95% Bayesian CI −1.03 to −0.27), −0.54 Udzungwa red colobus (Procolobus gordonorum) (−0.89 to −0.22), and −0.33 Sykes' monkey (Cercopithecus mitis monoides) (−0.63 to −0.07). Some responses to habitat factors were shared, notably the negative effect of elevation and the positive effect of climber coverage. These results are important for conservation science and practice because: the among-populations negative responses to anthropogenic disturbance provides a foundation for development of conservation plans that hold at the landscape scale, which is a comprehensive and cost-efficient approach; the among-species consistency in responses suggests conservation measures may be generalized at the guild level, which is especially relevant given the functional importance of primates in tropical rainforests; and the greater primate densities in areas at low elevation, which are closer to human settlements, point to specific management recommendations, such as the creation of buffer zones and prioritization of areas for protection.     

An agent-based model of red colobus resources and disease dynamics implicates key resource sites as hot spots of disease transmission

The effect of anthropogenic landscape change on disease in wildlife populations represents a growing conservation and public health concern. Red colobus monkeys (Procolobus rufomitratus), an endangered primate species, are particularly susceptible to habitat alteration and have been the focus of a great deal of disease and ecological research as a result. To infer how landscape changes can affect host and parasite dynamics, a spatially explicit agent-based model is created to simulate movement and foraging of this primate, based on a resource landscape estimated from extensive plot-derived tree population data from Kibale National Park, Uganda. Changes to this resource landscape are used to simulate effects of anthropogenic forest change. With each change in the landscape, disease outcomes within the simulated red colobus population are monitored using a hypothetical microparasite with a directly transmitted life cycle. The model predicts an optimal distribution of resources which facilitates the spread of an infectious agent through the simulated population. The density of resource rich sites and the overall heterogeneity of the landscape are important factors contributing to this spread. The characteristics of this optimal distribution are similar to those of logged sections of forest adjacent to our study area.     

A Study of Plant Species Extinction in Singapore: Lessons for the Conservation of Tropical Biodiversity

The native vascular plant flora of the Republic of Singapore has suffered the extinction of 594 out of a total 2277 species. These represent local, not global, species extinctions. Coastal habitats, including mangroves, have lost 39% of their species, while inland forests have last 29%. Epiphytic species (62% loss) appear particularly prone to extinction, which is reflected in a similar disposition exhibited by the Orchidaceae. Deforestation and disturbance have been the main cause of plant species extinction in Singapore. The rich mangrove epiphyte flora has been totally exterminated, and a number of tree species are reduced to populations of a few mature individuals. Many more species continue to survive than the species-area relationship would predict given the 99.8% loss of primary forest. This is interpreted as a result of the failure of equilibrium to be achieved yet in the remnant forest fragments, even after more than a century of isolation. Singapore's secondary forests appear to accrete plant diversity very slowly, even if contiguous with primary forest areas. We conclude that remnant fragments of primary tropical forest, even of very small size, can play a major role in the conservation of tropical biodiversity. The patterns of extinction observed in Singapore indicate that coastal and estuarine sites are in greatest demand for development and therefore must be given high priority for conservation despite their somewhat lower biodiversity. Epiphyte and orchid diversity appear to be very good indicators of the degree of disturbance suffered by a habitat in the humid tropics.     

Variable resource defense by the Tana River crested mangabey

Summary Behavioral observations over 16 months of two groups of Tana River crested mangabeys (Cercocebus galeritus galeritus) in East Africa provide evidence, contrary to previous reports, for site-specific aggression and territorial exclusion. In addition, movements and vocal responses to neighboring group's long-call vocalizations vary temporally, reflecting seasonal variation in food availability and distribution. Patterns of response to neighboring groups are consistent with the hypothesis that resources should be defended only when it is economic to do so. When fruit resources are rare intergroup interactions are infrequent and groups use separate areas. As fruit availability increases, the distribution of diet species influences the type of interaction; peaceful intergroup interactions generally occur when mangabeys eat uniformly distributed species and aggressive interactions occur when mangabeys eat species with patchy distributions. Differences between male vocal responses and group spatial responses may reflect conflicting objectives of territorial defense by males and females.     

Ecology and Conservation of the Endangered American Burying Beetle (Nicrophorus americanus)

Field studies were conducted on the western population of the endangered American burying beetle (Nicrophorus americanus) in Oklahoma and Arkansas to determine its habitat affinities. A common cause of declining populations is some specialized adaptation that makes it difficult to respond to a rapidly changing habitat. We evaluated the hypothesis that N. americanus is a habitat specialist in its search for food, preferring mature forests with deep, humic soils. This hypothesis was rejected. Based on comparisons of niche breadth among syntopic congeners and niche overlap, N. americanus is relatively generalized in its use of a range of habitats when searching for food. It is likely that the generalist nature and the endangered status of N. americanus both derive from the fact that it is the largest member of its guild. In comparison to smaller species, N. americanus breeds on larger carcasses, which are more unpredictable in space and time. It is likely, therefore, that N. americanus must search over a larger area and greater diversity of habitats than its smaller congeners.     

Effects of Restoring Oak Savannas on Bird Communities and Populations

Abstract:  Efforts to restore and maintain oak savannas in North America, with emphasis on the use of prescribed fire, have become common. Little is known, however, about how restoration affects animal populations, especially those of birds. I compared the breeding densities, community structure, and reproductive success of birds in oak savannas maintained by prescribed fire (12 sites) with those in closed-canopy forests (13 sites). All sampling was conducted in Illinois (U.S.A.). Of the 31 bird species analyzed, 12 were more common in savannas, 14 were not affected by habitat structure, and 5 were more common in forest habitat. The species favored by disturbance and restoration included Northern Bobwhites ( Colinus virginianus ), Mourning Doves (  Zenaida macroura ), Red-headed Woodpeckers (  Melanerpes erythrocephalus ), Indigo Buntings (  Passerina cyanea ), and Baltimore Orioles ( Icterus galbula ). Those more common in closed-canopy forest included Ovenbirds ( Seiurus aurocapilla ) and Wood Thrushes (  Hylocichla mustelina ). Few species were unique to one type of habitat, but overall avian community structure in oak savannas and closed-canopy forests was generally distinctive. Estimates of nesting success (derived from 785 nests) revealed that 6 of the 13 species considered experienced greater productivity in the savanna habitat. Rates of brood parasitism were unaffected by restoration and habitat structure. Within savannas, tract size had little effect on breeding abundances and reproductive success. My results illustrate that restoration techniques can significantly affect the ecology of constituent animal populations and communities and have key implications regarding avian conservation and the management of forest habitat in fragmented landscapes. Small patches of forest habitat that regularly function as population sinks may offer far better prospects for birds if they are subjected to disturbance and ecosystem restoration.     

Characterizing the spatial structure of songbird cultures

Recent advances have shown that human-driven habitat transformations can affect the cultural attributes of animal populations in addition to their genetic integrity and dynamics. Here I propose using the song of oscine birds for identifying the cultural spatial structure of bird populations and highlighting critical thresholds associated with habitat fragmentation. I studied song variation over a wide geographical scale in a small and endangered passerine, the Dupont's Lark Chersophilus duponti, focusing on (1) cultural population structure, to determine a statistical representation of spatial variation in song and identify cultural units, and (2) the minimum patch size needed for an individual to develop a stable repertoire. I found that overall song diversity depends on variation among populations (beta-cultural diversity). Abrupt thresholds occurred in the relationships between individual song dissimilarity and geographic distance, and between individual song diversity and patch area. Spatial autocorrelation analysis showed that populations located as little as 5 km apart may have independently evolved their song traditions. Song diversity stabilized in patches as small as 100 ha supporting as few as 8-20 males. Song repertoires of smaller patches were significantly poorer. Almost one-quarter of the study populations inhabited patches <100 ha, and their cultural traditions appear to have eroded. The analysis of spatial patterns in birdsong may be a useful tool for detecting subpopulations prone to extinction.     

Wood Thrush Populations Are Not All Sinks in the Agricultural Midwestern United States

Abstract: Conservation strategies for forest-breeding, Neotropical migratory birds focus on the identification and preservation of source habitats. In sources, populations maintain relatively high levels of reproductive success, whereas in sinks, reproductive success is consistently below net replacement rate. In agricultural regions of the midwestern United States, forest patches of various sizes appear to act as sinks for Neotropical migrants. In 1994–1996 I monitored Wood Thrush (   Hylocichla mustelina ) nests in four forest patches in an agricultural landscape in northern Indiana. Given the prevailing estimates of adult and juvenile survival, I report productivity data that show substantial annual variation and that are sufficient to suggest the maintenance of temporal sources. Indeed, some Wood Thrush populations may act as source habitats in regions with relatively high levels of Brown-headed Cowbird (   Molothrys ater ) parasitism and nest predation because pairs produce multiple clutches and have the ability to fledge cowbirds and their own young from parasitized nests. My results and those from other studies of Wood Thrushes in landscapes with fragmented forests illustrate the variable ways in which source-sink dynamics are affected by habitat fragmentation. In some agricultural regions, populations in small forest patches may act as sources for Wood Thrushes and may be a legitimate focus of conservation efforts aimed at some migratory songbirds.     

Spotted Owls and Old Growth Logging in the Pacific Northwest

Abstract: Northern Spotted Owls, Strix occidentalis caurina, require large tracts of old-growth conifer forest to survive and reproduce. Much of this forest has been or is being cut by commercial logging operations, with uncertain consequences for the owls. In this paper I present simulation models of owl population change over the next 100 years, as summing a variety of scenarios for habitat destruction and fragmentation. My analysis differs from previous models by incorporating patchy territory distribution and random environmental fluctuations. Fragmented and patchy habitat distributions are common problems for endangered organisms, but they have received little attention from modelers. My results indicate that yearly fluctuations in breeding success have little impact on owl populations, but that spatial structure is quite important and should be considered in planning forest preservation. The simulations suggest that for all reasonable parameter values the proposed US. Forest Service logging plans will lead to the demise of the owls.     

Mature and old-growth riparian forests: structure, dynamics, and effects on Adirondack stream habitats.

Riparian forests regulate linkages between terrestrial and aquatic ecosystems, yet relationships among riparian forest development, stand structure, and stream habitats are poorly understood in many temperate deciduous forest systems. Our research has (1) described structural attributes associated with old-growth riparian forests and (2) assessed linkages between these characteristics and in-stream habitat structure. The 19 study sites were located along predominantly first- and second-order streams in northern hardwood-conifer forests in the Adirondack Mountains of New York (U.S.A.). Sites were classified as mature forest (6 sites), mature with remnant old-growth trees (3 sites), and old-growth (10 sites). Forest-structure attributes were measured over stream channels and at varying distances from each bank. In-stream habitat features such as large woody debris (LWD), pools, and boulders were measured in each stream reach. Forest structure was examined in relation to stand age using multivariate techniques, ANOVA, and linear regression. We investigated linkages between forest structure and stream characteristics using similar methods, preceded by information-theoretic modeling (AIC). Old-growth riparian forest structure is more complex than that found in mature forests and exhibits significantly greater accumulations of aboveground tree biomass, both living and dead. In-stream LWD volumes were significantly (alpha = 0.05) greater at old-growth sites (200 m3/ha) compared to mature sites (34 m3/ha) and were strongly related to the basal area of adjacent forests. In-stream large-log densities correlated strongly with debris-dam densities. AIC models that included large-log density, debris-dam density, boulder density, and bankfull width had the most support for predicting pool density. There were higher proportions of LWD-formed pools relative to boulder-formed pools at old-growth sites as compared to mature sites. Old-growth riparian forests provide in-stream habitat features that have not been widely recognized in eastern North America, representing a potential benefit from late-successional riparian forest management and conservation. Riparian management practices (including buffer delineation and restorative silvicultural approaches) that emphasize development and maintenance of late-successional characteristics are recommended where the associated in-stream effects are desired.     

Mass Differences among Male Mangabey Monkeys Inhabiting Logged and Unlogged Forest Compartments

Abstract: Remedies for reduction in primate numbers following rainforest habitat disturbance must incorporate understanding of how disturbance affects population biology. Between July 1996 and July 1998, I captured 31 adult male grey cheeked mangabeys (  Lophocebus albigena) from groups occupying logged and unlogged forest in Kibale National Park, Uganda. Captured males were weighed, measured, fitted with radiocollars, and radiotracked three to five times a week. Males from groups in the unlogged forest were significantly heavier than males from the logged forest. Males that immigrated into the study groups were significantly lighter than resident males in unlogged forest, but they did not differ in mass from males in logged forest. I tested hypotheses that these differences were due to differences in age, skeletal size, and tissue mass. Results support the hypothesis that differences are due to differences in tissue mass. Results of further tests showed that differences in tissue mass were explained more by differences in habitat type than by rates of male turnover. There was no evidence to suggest that differences in tissue mass were related to differences in costs of travel, crowding, or seasonal variation in habitat quality. My results suggest that selective logging may affect primate biomass, although these changes may or may not be reflected in estimates of primate density.     

Local and Landscape Correlates of Primate Distribution and Persistence in the Remnant Lowland Rainforests of the Upper Brahmaputra Valley,Northeastern India

Habitat fragmentation affects species distribution and abundance, and drives extinctions. Escalated tropical deforestation and fragmentation have confined many species populations to habitat remnants. How worthwhile is it to invest scarce resources in conserving habitat remnants within densely settled production landscapes? Are these fragments fated to lose species anyway? If not, do other ecological, anthropogenic, and species‐related factors mitigate the effect of fragmentation and offer conservation opportunities? We evaluated, using generalized linear models in an information‐theoretic framework, the effect of local‐ and landscape‐scale factors on the richness, abundance, distribution, and local extinction of 6 primate species in 42 lowland tropical rainforest fragments of the Upper Brahmaputra Valley, northeastern India. On average, the forest fragments lost at least one species in the last 30 years but retained half their original species complement. Species richness declined as proportion of habitat lost increased but was not significantly affected by fragment size and isolation. The occurrence of western hoolock gibbon (Hoolock hoolock) and capped langur (Trachypithecus pileatus) in fragments was inversely related to their isolation and loss of habitat, respectively. Fragment area determined stump‐tailed (Macaca arctoides) and northern pig‐tailed macaque occurrence (Macaca leonina). Assamese macaque (Macaca assamensis) distribution was affected negatively by illegal tree felling, and rhesus macaque (Macaca mulatta) abundance increased as habitat heterogeneity increased. Primate extinction in a fragment was primarily governed by the extent of divergence in its food tree species richness from that in contiguous forests. We suggest the conservation value of these fragments is high because collectively they retained the entire original species pool and individually retained half of it, even a century after fragmentation. Given the extensive habitat and species loss, however, these fragments urgently require protection and active ecological restoration to sustain this rich primate assemblage. Correlaciones Locales y de Paisaje de la Distribución y Persistencia de Primates en los Bosques Lluviosos Remanentes en el Valle del Alto Brahmaputra, Noreste de India     

Fire and forest landscapes in the Georgia Piedmont: an assessment of spatial modeling assumptions

Landscape simulation models are widely used to study the behavior of ecological systems. As computing power has increased, these models have become more complex and incorporated more realistic spatial representations of landscape patterns and ecological processes. The goal of this research was to examine the sensitivity of simulated landscape patterns to fundamental spatial modeling assumptions. The LANDIS simulator was parameterized for forests of the Georgia Piedmont and used to model landscape-scale community dynamics at fire return intervals from 20 to 100 years. A base scenario incorporating localized seed dispersal along with landform-related variation in species establishment rates and disturbance regimes was contrasted with three alternative scenarios. The uniform habitat scenario applied the same set of species establishment coefficients across all landforms. The uniform dispersal scenario removed the effects of seed source abundance and pattern on species establishment. The uniform disturbance scenario assumed identical disturbance regimes on all landforms.At the shortest fire return intervals, fire severities were low and the stand age distribution was dominated by older forests. At longer fire return intervals, fire severities were high and the stand age distribution was skewed toward younger forests. Species composition generally followed a gradient from fire-resistant species at short fire return intervals to fire-sensitive species at longer fire return intervals. However, some species exhibited bimodal distributions with high abundances at both short and long fire return intervals. Landscape responses to fire were similar in the uniform habitat scenario and the base scenario. Communities were less sensitive to fire return interval and had more fire-sensitive species in the uniform dispersal scenario than in the base scenario. Species composition in the uniform disturbance scenario was similar to the base scenario for the longest fire-intervals, but was more sensitive to changes in the fire regime at shorter fire return intervals. In models of Piedmont forest landscapes, accurate spatial representations of dispersal and fire regime heterogeneity are essential for predicting landscape-scale species composition under changing fire regimes. In contrast, the precise spatial representation of species–habitat relationships may be considerably less important.     

Scale-Dependent Effects of Habitat Disturbance on Species Richness in Tropical Forests

Abstract: Despite growing concern, no consensus has emerged over the effects of habitat modification on species diversity in tropical forests. Even for comparatively well-studied taxa such as Lepidoptera, disturbance has been reported to increase and decrease diversity with approximately equal frequency. Species diversity within landscapes depends on the spatial scale at which communities are sampled, and the effects of disturbance in tropical forests have been studied at a wide range of spatial scales. Yet the question of how disturbance affects diversity at different spatial scales has not been addressed. We reanalyzed data from previous studies to examine the relationship between spatial scale and effects of disturbance on tropical-forest Lepidoptera. Disturbance had opposite effects on diversity at large and small scales: as scale decreased, the probability of a positive effect of disturbance on diversity increased. We also explicitly examined the relationship between spatial scale and the diversity of butterflies in selectively logged and unlogged forest in Maluku Province, Indonesia. Species richness increased with spatial scale in both logged and unlogged forest, but at a significantly faster rate in unlogged forest, whereas species evenness increased with scale in unlogged forest but did not increase with scale in logged forest. These data indicate that the effects of habitat modification on species diversity are heavily scale-dependent. As a result, recorded effects of disturbance were strongly influenced by the spatial scale at which species assemblages were sampled. Future studies need to account for this by explicitly examining the effects of disturbance at a number of different spatial scales. A further problem arises because the relationship between scale and diversity is likely to differ among taxa in relation to mobility. This may explain to some extent why the measured effects of disturbance have differed between relatively mobile and immobile taxa.     

The Value of Primary, Secondary, and Plantation Forests for a Neotropical Herpetofauna

Abstract:  Plantation forests and second-growth forests are becoming dominant components of many tropical forest landscapes. Yet there is little information available concerning the consequences of different forestry options for biodiversity conservation in the tropics. We sampled the leaf-litter herpetofauna of primary, secondary, and Eucalyptus plantation forests in the Jari River area of northeastern Brazilian Amazonia. We used four complementary sampling techniques, combined samples from 2 consecutive years, and collected 1739 leaf-litter amphibians (23 species) and 1937 lizards (30 species). We analyzed the data for differences among forest types regarding patterns of alpha and beta diversity, species-abundance distributions, and community structure. Primary rainforest harbored significantly more species, but supported a similar abundance of amphibians and lizards compared with adjacent areas of second-growth forest or plantations. Plantation forests were dominated by wide-ranging habitat generalists. Secondary forest faunas contained a number of species characteristic of primary forest habitat. Amphibian communities in secondary forests and Eucalyptus plantations formed a nested subset of primary forest species, whereas the species composition of the lizard community in plantations was distinct, and was dominated by open-area species. Although plantation forests are relatively impoverished, naturally regenerating forests can help mitigate some negative effects of deforestation for herpetofauna. Nevertheless, secondary forest does not provide a substitute for primary forest, and in the absence of further evidence from older successional stands, we caution against the optimistic claim that natural forest regeneration in abandoned lands will provide refuge for the many species that are currently threatened by deforestation .     

Managing Boreal Forest Landscapes for Flying Squirrels

Abstract: Flying squirrel (Pteromys volans) populations have declined severely during the past few decades, and the species has become a focal species in forest management and the conservation debate in Finland. We compared landscape structure around known flying squirrel home ranges with randomly chosen forest sites to determine which landscape patterns characterize the areas occupied by the species in northern Finland. We sought to identify the key characteristics of the landscape that support the remaining flying squirrel populations. We analyzed landscape structure within circular areas with 1- and 3-km radii around 63 forest sites occupied by flying squirrels, and around 96 random sites. We applied stepwise analysis of the landscape structure where landscapes were built up step-by-step by adding patch types in order of their suitability for the flying squirrel. The land-use and forest-resource data for the analysis were derived from multisource national forest inventory and imported to a geographical information system. Landscape patch types were divided into three suitability categories: breeding habitat (mixed spruce-deciduous forests); dispersal habitat ( pine and young forests); and unsuitable habitat ( young sapling stands, open habitats, water). Flying squirrel landscapes contained more suitable breeding habitat patches and were better connected by dispersal habitats than random landscapes. Our results suggest that for the persistence of the flying squirrel, forest managers should 1) maintain a deciduous mixture, particularly in spruce-dominated forests; 2) maintain physical connectivity between optimal breeding habitats; and 3) impose coarse-grained structures on northeastern Finnish landscapes at current levels of habitat availability.     

Predation risk and the number of adult males in a primate group: a comparative test

The number of adult males in a bisexual primate group is thought to be determined mainly by the defensibility of mating access to the females. However, among primates, small groups sometimes contain several adult male. We evaluate the hypothesis that high predation risk may lead to greater male representation in primate groups, independent of the effect of group size. Male primates are known to be more vigilant than females, and may also be better at detecting potential predators. A comparative test was done using arboreal folivores in three continents, howler monkeys in the Neotropics, colobus monkeys in Africa and langurs in South and Southeast Asia. Howlers and colobus are exposed to predation by large monkey-eating eagles, whereas the langurs are not. We conducted regression analyses on group composition data of single populations and on mean group compositions among populations, and found that the arboreal langurs basically live in groups with only a single adult males whereas groups of howler and colobus monkeys of comparable size have multiple adult males (Fig. 3). Thus, the hypothesis was supported. Several alternative hypotheses do not account for this pattern.     

Response of a Group of Sichuan Snub-Nosed Monkeys to Commercial Logging in the Qinling Mountains, China

Abstract:  Habitat destruction is one of the greatest threats to primates worldwide. To understand the impact of forest logging on the habitat use of primates in temperate mixed forest, we compared the range, habitat used, population size, and diet of a troop (ERT) of Sichuan snub-nosed monkeys ( Rhinopithecus roxellana ) in the Qinling Mountains before (1989), during (1997), and after (2002–2003) commercial logging. Logging significantly changed the composition of the forest and the food supply for the troop. Some areas were heavily logged and formed patches in the forest that lacked canopy cover. The troop moved 7 km away from their original range when logging took place and returned to their original range after logging stopped, but they avoided heavily logged areas that lacked canopy cover. Their movement indicated some degree of site fidelity in this species. Diet and home range changed after logging, but the population size remained stable, which suggests that this species has some ability to adapt to habitat changes. Our results may reflect a natural flexibility in primates to adapt to the changing food resources in temperate areas with marked seasonal variations in food availability and distribution. This flexibility may have contributed to their higher degree of resilience to habitat alterations caused by human activities compared with tropical forest primates that have a more specialized diet. Our findings provide important baseline information that will help decision makers in their efforts to conserve primates, especially in temperate regions, and to sustainably manage primate habitat.     

Ontogeny of provisioning in two populations of wild golden lion tamarins (Leontopithecus rosalia)

Provisioning weaned young is an important part of the cooperative rearing system of marmosets and tamarins (family: Callitrichidae). Juvenile callitrichids receive a substantial proportion of their diet from all adult group members, whereas juveniles of most other primate species only receive food from the mother infrequently via scrounging. We conducted a longitudinal study of provisioning to 21 young wild golden lion tamarins through their first year of life in two Brazilian reserves. Juveniles were predicted to experience higher provisioning rates at the site with mature forest (the presumed ancestral habitat) and in territories that contained a higher proportion of preferred habitat within the mature forest reserve. Key measures of provisioning did not differ substantially between habitat types. The rates at which juveniles begged for food were very similar across habitats, while the influence of habitat on the rates at which juveniles received food was small and varied across age groups. The most pronounced differences between the reserves were: adult resistance to food-transfer attempts was less frequent, food-offering calls before food transfer were more frequent, and the proportion of prey provisioned was higher in the reserve in which earlier successional-stage forest predominated. Within the mature forest reserve, begging success of young juveniles covaried positively with preferred habitat. Rather than overt caretaker–offspring conflict, an information–feedback loop between juveniles and adults appears to drive provisioning changes as juveniles mature. Direct measures of resource abundance are needed to help clarify the mechanisms by which forest successional stage influences provisioning.