Spider Monkey Populations Research Articles

HEMATOLOGIC REFERENCE INTEVALS FOR SPIDER MONKEYS (ATELES GEOFFROYI) IN MANAGED CARE WITH RESPECT TO SEX AND AGE.

The determination of health status in spider monkeys (Ateles geoffroyi) that are held in managed care requires periodic evaluation. The present study obtained baseline data on hematologic values, body weight, and length in A. geoffroyi. A total of 118 individuals from three housing centers were included in the study and grouped into two categories by age (92 adults, 26 juveniles) and sex (46 males, 72 females). Body weight, red blood cell (RBC) counts, and hemoglobin counts were significantly higher in adult males than in adult females. No differences in length were found between sex and age groups. The present findings indicate that hematologic values by age and sex in A. geoffroyi are similar to those reported in other spider monkey populations in both managed care and the wild. These results will be useful as a reference for young individuals and adults in future studies of the health of this species.

Genetic diversity of the endangered black-handed spider monkey <i>Ateles geoffroyi</i> (Primates: Atelidae) in a fragmented landscape of El Salvador

Spider monkeys (genus Ateles) are distributed across rainforests from southern Mexico to northern Bolivia, but at risk of extinction across much of their range. Like most members of the genus, the black-handed spider monkey, or the Central American spider monkey, Ateles geoffroyi is particularly vulnerable to anthropogenic threats, due to its inability to persist in disturbed and/or isolated forest patches and is categorized as “Endangered” by the IUCN. Within its range in El Salvador, the smallest country in Central America, the spider monkey has now been restricted to isolated patches of semi-deciduous forests, including four fragments that lie within a disturbed agricultural landscape in Jiquilisco Bay, in Southeast El Salvador. We analyzed 73 noninvasive fecal samples from spider monkeys in this region, and we were able to identify 55 individuals. We evaluated the genetic diversity and structure of the four populations using microsatellite markers. Our results show higher observed than expected heterozygosity, but low genetic diversity compared to published data on other spider monkey populations (Ho = 0.50 – 0.57 and He = 0.39 – 0.51; allelic richness with rarefaction = 2.71 – 3.22; private alleles with rarefaction = 0.18 – 0.61). We also found significant differentiation across fragments (Fst = 0.2, P<0.001) and two genetically different groups. These findings suggest the need for conservation action to reconnect forest patches, to improve the unfavorable situation of the only non-human primate in El Salvador.

Female Spider Monkeys (Ateles geoffroyi) Cope with Anthropogenic Disturbance Through Fission-Fusion Dynamics.

Most primates live in habitats with some level of anthropogenic disturbance, and such disturbances have a larger impact on frugivorous primates that are more sensitive to ecological disruptions than folivores. Fecal glucocorticoid metabolites provide insight into how the external environment affects internal physiological state, and thus provide information on how anthropogenic pressures become embodied. Here, I examine how subgroup size and glucocorticoids vary with high and low fruit abundance, and how fruit abundance, subgroup size, and activity budget affect fecal glucocorticoid metabolites in female spider monkeys (Ateles geoffroyi) living in an anthropogenically disturbed habitat. I measured these variables via behavioral, ecological, and fecal sampling for 15 months in 17 female spider monkeys at El Zota Biological Field Station. Subgroup size was significantly larger during periods of high fruit abundance, but glucocorticoids did not differ between periods of low and high fruit abundance. Monthly fruit abundance predicted subgroup sizes significantly, but did not predict fecal glucocorticoid concentrations. Increased resting time and reproductive state predicted fecal glucocorticoid concentrations significantly, but travel and foraging time had no significant effect on glucocorticoid concentrations. Individual resting time over the study period correlated negatively with glucocorticoid concentrations. These results suggest that spider monkeys cope with variation in fruit abundance by adjusting subgroup size, and that these adjustments may mitigate environmental stress in this mildly seasonal environment. The large, relatively productive forest size at this site, and the availability of anthropogenic food sources, enable this population of spider monkeys to cope with human-induced habitat disturbance.

Medicinal plants in the diet of woolly spider monkeys (Brachyteles arachnoides, E. Geoffroy, 1806) – a bio-rational for the search of new medicines for human use?

The present study aimed to compare the plant food diet of woolly spider monkeys (Brachyteles arachnoides) inhabiting Intervales State Park in São Paulo, Brazil, with medicinal plant species used by humans in the surrounding areas of the park. The diet of a group of woolly spider monkeys living in an Atlantic forest area was recorded during 43 months of fieldwork. Fifty-three species (87 food items) were recorded. Plant specimens were collected and identified at the University of São Paulo and the Botanical Institute of São Paulo State. Using semi-structured interviews, ethnomedicinal data were also collected from four preselected respondents regarding the human therapeutic value of these plants. The study showed that 24.5% (13/53) of these species are used by residents around the park for medicinal purposes. Of these thirteen, seven species also have validated pharmacological properties, and three are utilized by local residents for similar medicinal purposes. Overlap in the plant food/medicinal diet of woolly spider monkey populations elsewhere were also noted, suggesting potential overlap in their medicinal value for humans and primates. The similarities between the ingestion of plants by primates and their medicinal use by humans provide a bio-rational for the search of bioactive plants in the primate diet. Further detailed investigation of their pharmacological and phytochemical value is warranted.

Population genetic patterns among social groups of the endangered Central American spider monkey (Ateles geoffroyi) in a human-dominated landscape.

Spider monkeys (Genus: Ateles) are a widespread Neotropical primate with a highly plastic socioecological strategy. However, the Central American species, Ateles geoffroyi, was recently re-listed as endangered due to the accelerated loss of forest across the subcontinent. There is inconsistent evidence that spider monkey populations could persist when actively protected, but their long-term viability in unprotected, human-dominated landscapes is not known. We analyzed noninvasive genetic samples from 185 individuals in 14 putative social groups on the Rivas Isthmus in southwestern Nicaragua. We found evidence of weak but significant genetic structure in the mitochondrial control region and in eight nuclear microsatellite loci plus negative spatial autocorrelation in Fst and kinship. The overall pattern suggests strong localized mating and at least historical female-biased dispersal, as is expected for this species. Heterozygosity was significantly lower than expected under random mating and lower than that found in other spider monkey populations, possibly reflecting a recent decline in genetic diversity and a threat from inbreeding. We conclude that despite a long history of human disturbance on this landscape, spider monkeys were until recently successful at maintaining gene flow. We consider the recent decline to be further indication of accelerated anthropogenic disturbance, but also of an opportunity to conserve native biodiversity. Spider monkeys are one of many wildlife species in Central America that is threatened by land cover change, and an apt example of how landscape-scale conservation planning could be used to ensure long-term persistence.

The Social Behavior of Brown Spider Monkeys (Ateles hybridus) in a Fragmented Forest in Colombia

Forest fragmentation and habitat loss are two of the main drivers of wildlife population declines. Animals exposed to habitat disturbances must develop behavioral strategies to adapt to novel, rapidly fluctuating socioecological challenges. Understanding the behavioral flexibility of endangered primates as a response to ecological challenges, e.g., anthropogenic habitat disturbance, is a key element in the design of successful conservation initiatives for remaining populations. We studied the social behavior of a group of 11 adult and subadult brown spider monkeys (Ateles hybridus) living in a recently isolated and densely populated forest fragment in the Magdalena River Valley, Colombia, and compared their behavior to that of other wild spider monkey populations. From June 2009 to July 2010 we assessed diet, activity budgets, and the rates of affiliative and agonistic interactions initiated and received by adult male and female spider monkeys. The diet of our focal group was quite different from that in most previous studies of Ateles: leaves accounted for ca. 40 % of their diet, and fruits represented barely half of their diet, suggesting that this population has had to adjust its feeding strategies to the local ecological challenges. We found no sex differences in the time males and females spent resting, moving, and socializing, but females tended to invest more time in feeding than males did. Male-to-female aggression was the most common agonistic interaction, and same-sex aggressions were almost absent. We found no significant differences in rates of grooming or embracing between the different types of dyads. The resemblance of our results to those of similar studies in less disturbed habitats suggests that spider monkeys might adapt to certain levels of ecological and social disturbance, at least initially, and are a starting point to understand better the initial effects of fragmentation on the behavioral repertoire of these primates.

Initial effects of fragmentation on the density of three neotropical primate species in two lowland forests of Colombia

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 13:41-50 (2010) - DOI: https://doi.org/10.3354/esr00312 Contribution to the Theme Section 'Responses of animals to habitat alteration' Initial effects of fragmentation on the density of three neotropical primate species in two lowland forests of Colombia Andres Link1,2,*, Ana Gabriela de Luna1,3, Felipe Alfonso4, Paola Giraldo-Beltran5, Fernando Ramirez6 1Proyecto Primates, Carrera 11a No. 91–55, Bogotá, Colombia 2Department of Anthropology, New York University, 25 Waverly Place, New York, New York 10003, USA 3Facultad de Ciencias Biologicas, Universidad Complutense de Madrid, c/ Jose Antonio Novais n 2 Ciudad Universitaria, Madrid 28040, Spain 4Departamento de Biologia, Pontificia Universidad Javeriana, Carrera 7 No. 40–62, Bogota, Colombia 5Programa de Agronomia, and 6Programa de Biologia, Universidad de Caldas, Calle 65 No. 26–10, Manizales, Colombia *Email: al898@nyu.edu ABSTRACT: Fragmentation and habitat destruction are 2 factors driving the current decline of mammal populations. Spider monkeys Ateles spp. are some of the first neotropical mammals to go extinct after fragmentation, as they (1) are large-bodied, specialized frugivores that require large areas to subsist, (2) are preferred targets for local hunters, (3) have slow reproductive cycles, and (4) rarely move between adjacent forest fragments. Brown spider monkeys A. hybridus are Critically Endangered, and most of their historical habitat has either been cleared or is seriously fragmented. We conducted census surveys at 2 areas in Colombia (Las Quinchas and San Juan) in order to compare the population density of brown spider monkeys, red howler monkeys Alouatta seniculus, and white-fronted capuchins Cebus albifrons in both continuous forest and recently fragmented forest in each of these 2 areas. We found a higher density of brown spider monkeys and red howler monkeys in recent fragments at both sites, while differences were not consistent for white-fronted capuchins. We suggest that these patterns could be explained by the constrained ability of spider monkeys and howler monkeys to move between forest fragments and to exploit impacted or degraded areas. In the absence of hunting, the immediate effects of fragmentation on spider monkeys seem to lead to a sudden increase in population density as a result of a decreasing forested area, while maintaining population numbers relatively stable. Longer-term research will lead to the identification of the proximate factors leading to the generalized pattern of local extinction of spider monkey populations in small isolated fragments. KEY WORDS: Ateles hybridus · Endangered species · Fragmentation · Line transects · Population density Full text in pdf format PreviousNextCite this article as: Link A, de Luna AG, Alfonso F, Giraldo-Beltran P, Ramirez F (2010) Initial effects of fragmentation on the density of three neotropical primate species in two lowland forests of Colombia. Endang Species Res 13:41-50. https://doi.org/10.3354/esr00312Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 13, No. 1. Online publication date: December 20, 2010 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2010 Inter-Research.

Modelling spider monkeys Ateles spp. Gray, 1825: ecological responses and conservation implications to increased elevation

Spider monkeys (Ateles spp.) are among the most widely-distributed and endangered neotropical primate genera. Throughout their distribution expanding human populations and associated demands for land are causing widespread deforestation, especially in low-lying areas where many populations of spider monkeys are being pushed to high elevation sites with sub-optimal conditions. In this paper ecological data from a wide range of sources has been collected and examined to try to better understand and predict spider monkey ecological responses to high elevation areas with lower environmental carrying capacities. Results show a significant reduction in group and foraging party sizes with increased elevation. A general reduction in density is also noted with increasing elevation, while home range sizes remain static. It is recommended that these observations be taken into account when planning conservation actions and new protected areas, and further implications are also discussed.

Modelling the long‐term sustainability of indigenous hunting in Manu National Park, Peru: landscape‐scale management implications for Amazonia

Summary 1. Widespread hunting throughout Amazonia threatens the persistence of large primates and other vertebrates. Most studies have used models of limited validity and restricted spatial and temporal scales to assess the sustainability. 2. We use human‐demographic, game‐harvest and game‐census data to parameterize a spatially explicit hunting model. We explore how population growth and spread, hunting technology and effort, and source–sink dynamics impact the density of black spider monkeys Ateles chamek over time and space in the rainforests of south‐eastern Peru. 3. In all scenarios, spider monkey populations, which are vulnerable to hunting, persist in high numbers in much of Manu National Park over the next 50 years. Nonetheless, shotguns cause much more depletion than traditional bow hunting by Matsigenka (Machiguenga) indigenous people. 4. Maintenance of the current indigenous lifestyle (dispersed settlements, bow hunting) is unlikely to deplete spider monkeys and, by extension, other fauna, despite rapid human population growth. This helps explain why large, pre‐Colombian human populations did not drive large primates to extinction. When guns are used, however, spider monkeys quickly become depleted around even small settlements, with depletion eventually reversing the short‐term harvest advantage provided by shotgun hunting. Thus, our models show that when guns are used, limits on settlement numbers can reduce total depletion. 5. Synthesis and applications. Our framework lets us visualize the future effects of hunting, population growth, hunting technology and settlement spread in tropical forests. In Manu Park, the continued prohibition of firearms is important for ensuring long‐term hunting sustainability. A complementary policy is to negotiate limits on new settlements in return for development aid in existing settlements. The advantage of the latter approach is that settlement numbers are more easily monitored than is hunting effort or technology. Similar policies could help to reduce landscape‐scale depletion of prey species in human‐occupied reserves and protected areas throughout the Amazon.

Survey and Conservation of a Relict Population of Spider Monkeys (Ateles Geoffroyi) in the Sumidero Canyon, Mexico

Habitat loss, hunting and the pet trade have caused significant reductions in the original distribution of spider monkeys ( Ateles spp.) in the Neotropics. Mexico harbors the northernmost distribution of this primate in the Neotropics, and information on the current location of remnant populations and on their demographic features in particularly scarce. In this paper we report the results of a month-long survey during the dry season of a population of spider monkeys ( Ateles geoffroyi vellerosus) existing in the rainforest vegetation of the Sumidero Canyon National Park in central Chiapas, Mexico. The 23km-long canyon was divided into five 5km-long segments and the rainforest vegetation at the edges of the river canyon was surveyed from a boat and on the ground for presence of spider monkeys. Surveys resulted in the detection of nine subgroups of spider monkeys in four of the 5km-long segments, for an estimated total population of 36 individuals. Average subgroup size ranged from 3−7 individuals, 28% of these were adult males, 36% were adult females, 28% were juveniles and 8% were infants. Relative abundance was estimated at 1.8 monkeys/km of river. The rainforest vegetation along the river canyon has a patchy distribution and patches are separated by the steep and very tall walls of the canyon. Spider monkeys were observed to move from patch to patch by climbing the walls of the canyon. This unusual behavior allows individual spider monkeys to secure food resources and to meet other conspecifics. Additional surveys are necessary to map annual fluctuations in the size and distribution of the spider monkey population in the canyon.

High population density of black-handed spider monkeys (Ateles geoffroyi) in Costa Rican lowland wet forest

The main objective of this study was to estimate the population density and demographic structure of spider monkeys living in wet forest in the vicinity of Sirena Biological Station, Corcovado National Park, Costa Rica. Results of a 14-month line-transect survey showed that spider monkeys of Sirena have one of the highest population densities ever recorded for this genus. Density estimates varied, however, depending on the method chosen to estimate transect width. Data from behavioral monitoring were available to compare density estimates derived from the survey, providing a check of the survey's accuracy. A combination of factors has most probably contributed to the high density of Ateles, including habitat protection within a national park and high diversity of trees of the fig family, Moraceae. Although natural densities of spider monkeys at Sirena are substantially higher than those recorded at most other sites and in previous studies at this site, mean subgroup size and age ratios were similar to those determined in previous studies. Sex ratios were similar to those of other sites with high productivity. Although high densities of preferred fruit trees in the wet, productive forests of Sirena may support a dense population of spider monkeys, other demographic traits recorded at Sirena fall well within the range of values recorded elsewhere for the species.

Seed dispersal by spider monkeys and its importance in the maintenance of neotropical rain-forest diversity

Seed dispersal by frugivores is thought to play an important role in the maintenance of tropical forest diversity. Spider monkeys (Ateles spp.) are amongst the most frugivorous primates known, and they incorporate a diverse array of fruit species in their diets. In a 1-y study in lowland Ecuador, 670 h of focal observations and data on 916 faecal depositions were collected, and these data are used to describe the seed dispersal patterns of one group of wild spider monkeys (Ateles belzebuth) in terms of both the quantity of seeds dispersed and the primary seed shadows generated. Spider monkeys fed on the fruits of at least 152 plant species and swallowed seeds from more than 98% of these. Collected faecal samples contained seeds from at least 133 different plant species, with an average of 1.9 species (range: 0–7) per defecation. Individual spider monkeys dispersed a minimum of ∼195 000 seeds >1 mm in diameter per year, ∼35 000 of which were >3 mm in diameter. Mean retention time for seeds was 4.5 h. Seed dispersal distances averaged 443 m, but some seeds were moved >1250 m away from parental sources. These results suggest that declines in populations of spider monkeys might have a direct effect on forest dynamics, especially if other disperser species cannot compensate for their lost ecological services.

A re-evaluation of factors influencing the sex ratio of spider monkey populations with new data from Maraca Island, Brazil.

A re-evaluation of factors influencing the sex ratio of spider monkey populations with new data from Maraca Island, Brazil.

An analysis of adult social spacing tendencies and related social interactions in a colony of spider monkeys (Ateles geoffroyi) at the San Francisco zoo.

Observations on adult interindividual spacing and social interactions for 13 spider monkeys (Ateles geoffroyi) of an approximately 48 animal captive colony were made from mid-June through August 1972. In this analysis the interanimal distances, general activities, and social interactions per minute observation for each subject were compared for a sample of 7 sexually mature males and 6 sexually mature females. Association tendencies between members of the same sex were significantly high as were exchanges of the taxon-specific 'pectoral sniff and embrane" interactions and grooming. The direction and nature of agonistic interactions was predominantly intersexual and involved frequent attacks by single or multiple males against females. Comparisons with a feral population of spider monkeys (Ateles belzebuth) revealed marked similarities in spatial affinities and patterns of social interaction.