18 research outputs found
Distribution and conservation status of the orang-utan (Pongo spp.) on Borneo and Sumatra: how many remain?
In recognition of the fact that orang-utans (Pongo spp.) are severely threatened, a meeting of orang-utan experts and conservationists, representatives of national and regional governmental and non-governmental organizations, and other stakeholders, was convened in Jakarta, Indonesia, in January 2004. Prior to this meeting we surveyed all large areas for which orang-utan population status was unknown. Compilation of all survey data produced a comprehensive picture of orang-utan distribution on both Borneo and Sumatra. These results indicate that in 2004 there were c. 6,500 P. abelii remaining on Sumatra and at least 54,000 P. pygmaeus on Borneo. Extrapolating to 2008 on the basis of forest loss on both islands suggests the estimate for Borneo could be 10% too high but that for Sumatra is probably still relatively accurate because forest loss in orang-utan habitat has been low during the conflict in Aceh, where most P. abelii occur. When those population sizes are compared to known historical sizes it is clear that the Sumatran orang-utan is in rapid decline, and unless extraordinary efforts are made soon, it could become the first great ape species to go extinct. In contrast, our results indicate there are more and larger populations of Bornean orang-utans than previously known. Although these revised estimates for Borneo are encouraging, forest loss and associated loss of orang-utans are occurring at an alarming rate, and suggest that recent reductions of Bornean orang-utan populations have been far more severe than previously supposed. Nevertheless, although orang-utans on both islands are under threat, we highlight some reasons for cautious optimism for their long-term conservatio
Individual, social, and environmental factors affecting salivary and fecal cortisol levels in captive pied tamarins (Saguinus bicolor)
This is the peer reviewed version of the following article: Price, E., Coleman, R., Ahsmann, J., Glendewar, G., Hunt, J., Smith, T. & Wormell, D. (2019). Individual, social, and environmental factors affecting salivary and fecal cortisol levels in captive pied tamarins (Saguinus bicolor). American Journal of Primatology, 81(8), which has been published in final form at https://doi.org/10.1002/ajp.23033. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingPied tamarins (Saguinus bicolor) are endangered New World primates, and in captivity
appear to be very susceptible to stress. We measured cortisol in 214 saliva samples
from 36 tamarins and in 227 fecal samples from 27 tamarins, and investigated
the effects of age, sex, pregnancy, rearing history, social status, weight, group
composition, and enclosure type using generalized linear mixed models. There was no
effect of age on either fecal or salivary cortisol levels. Female pied tamarins in late
pregnancy had higher fecal cortisol levels than those in early pregnancy, or
nonpregnant females, but there was no effect of pregnancy on salivary cortisol.
Females had higher salivary cortisol levels than males, but there was no effect of
rearing history. However, for fecal cortisol, there was an interaction between sex and
rearing history. Handâreared tamarins overall had higher fecal cortisol levels, but
while male parentâreared tamarins had higher levels than females who were parentâ
reared, the reverse was true for handâreared individuals. There was a trend towards
lower fecal cortisol levels in subordinate individuals, but no effect of status on
salivary cortisol. Fecal but not salivary cortisol levels declined with increasing weight.
We found little effect of group composition on cortisol levels in either saliva or feces,
suggesting that as long as tamarins are housed socially, the nature of the group is of
less importance. However, animals in offâshow enclosures had higher salivary and
fecal cortisol levels than individuals housed onâshow. We suggest that large onâshow
enclosures with permanent access to offâexhibit areas may compensate for the
effects of visitor disturbance, and a larger number of tamarins of the same species
housed close together may explain the higher cortisol levels found in tamarins living
in offâshow accommodation, but further research is needed
Simulation model for contraceptive management of the Assateague Island feral horse population using individual-based data
The National Park Service (NPS) manages a culturally significant population of feral horses (Equus caballus) inhabiting the Maryland portion of Assateague Island, a barrier island in the eastern United States. Rapid growth of this population over the past few decades from 28 to 166 horses negatively impacts native species and ecological processes on the island. Since 1994, contraception via porcine zona pellucida vaccine has been used to control horse numbers, although herd reduction has been slower than initially expected, leading NPS to consider other management options. An individual-based stochastic simulation model was developed using the Vortex software program to examine the effects of different management strategies on the population. Data from the managed population were used to populate the model parameters. Model projections over the next 50 years using current management practices show an average rate of population decline of 13% per year, suggesting that the population will reach the management target of 80-100 horses in 5-8 years. The effectiveness of contraception to reduce the herd and maintain it at various target sizes of 20-100 horses was also assessed. The accumulation of inbreeding at each target population size was also modelled. Š CSIRO 2008
Effect of Enclosure Size and Complexity on the Behaviors of Captive Chimpanzees (Pan troglodytes)
Reports describing the implementation of innovative facility designs are important to both the primate caregiving community and policymakers reviewing current U.S. Department of Agriculture regulations. This study documents the changes in behavior of 5 adult chimpanzees that coincided with transfer from the Psychology Building Facility to the large and complex chimpanzee enclosure within the Chimpanzee and Human Communication Institute (CHCI) in Ellensburg, Washington. In 1993, the chimpanzees were relocated from a small facility with a 27.87-m² indoor suite of enclosures to a new 587-m² indoor and outdoor facility. The 1st study compares the activity budgets of the chimpanzees before and after the transfer. The 2nd study compares patterns of locomotion at the 2 facilities. The 3rd study examines the chimpanzees\u27 patterns of use of the features at the new facility. The chimpanzees traveled more and exhibited more species-typical behaviors at the CHCI, including climbing and leaping. The pattern of locomotion and postures at the CHCI was similar to the pattern of locomotion and postures observed in free-ranging chimpanzee populations. The chimpanzees used all structures and all areas in the facility, especially elevated structures and the outdoor enclosure
Orangutan population biology, life history, and conservation. Perspectives from population viability analysis models
Orangutan populations are particularly susceptible to local extinction due to hunting, habitat loss, and fragmentation because they live at low population densities, grow slowly, and reproduce rarely. This chapter uses Population Viability Analysis (PVA) to consider the conservation implications of orangutan life history and population biology. First, a baseline model that incorporates the best available orangutan life-history data is presented. This model is then used to examine how plausible variation in model parameters, changes in the intensity of human-induced threats, and different conservation and management interventions would affect the probability of orangutan population persistence. The effects of existing threats on the extinction risk of specific orangutan populations on Borneo and Sumatra are also modelled. Finally, the conservation and management implications of this modeling exercise are considered