Abstract: The western purple-faced langur Trachypithecus vetulus nestor is a Critically Endangered primate endemic to Sri Lanka according to the International Union for Conservation of Nature (IUCN). Its population decline is inferred mainly due to vast habitat loss. Few recent data Eire available regarding its distribution or abundance. The ann Of Our study was to assess the conservation status of T. v. nestor throughout its known historical range by establishing presence/absence and correlating these data with semi-structured interviews determining human perceptions and threats. Twenty-six sites were investigated, with presence of T v. nestor being confirmed at 11 and indicated through questionnaires only at 2 additional sites. The present distribution of T v nestor is severely fragmented both locally and regionally. More than half of the populations comprised 1 or 2 groups only and, being isolated in a matrix of urban landscapes, are close to unviable. Conflicts between local people and T if. nestor were identified at such sites, where reports of troops crop-raiding gardens and plantations were associated with negative perceptions. Consequences for crop-raiding langurs ranged from shouting to (infrequently) shooting and killing by dogs, Negative views towards T v. nestor were significantly related to the length of time they spent in anthropogenic landscapes, while more positive views were significantly associated with the length of time T v. nestor spent in forested areas. Evidence of local extinctions means that the remaining, yet. increasingly fragmented habitat of the highly arboreal T v. nestor is critical for survival. Intervention to manage this human-wildlife conflict is vital. An integrated approach using international and local conservation authorities is highly recommended.

Disease outbreaks, either in isolation or in concert with other risk factors, can pose serious
threats to the long-term persistence of mammal populations [Cleaveland et al., 2001]; these risks are
elevated as population size decreases and/or population isolation increases. Currently, there is widespread
perception that infectious diseases pose one of the greatest risks to the survival of apes in the wild
[Altizer et al., 2007; Chi et al., 2007; Homsy, 1999; Ko¨ndgen et al., 2008; Leendertz et al., 2006;
Pederson et al., 2007]. Although difficult to diagnose, numerous infections or syndromes have been described
in wild great apes and epidemic disease has proven to be a critical cause of death in some cases
[Leendertz et al., 2006]. Examples include: Ebola virus in Taı¨ chimpanzees [Formenty et al., 1999] and
lowland gorillas [Bermejo et al., 2006; Walsh et al., 2003]; anthrax in Taı¨ chimpanzees [Leendertz et al.,
2004]; and an ‘‘AIDS-like'' disease in Mahale [Nishida et al., 2003]. Many of these disease outbreaks
are suspected to be the result of close contact with humans [Barnett et al., 2004; Chi et al., 2007;
Ferber, 2000; Goldberg et al., 2007; Homsy, 1999] and as such, the mitigation and/or management of
these risks is one of the highest priorities within the ape conservation community. Ko¨ndgen et al. [2008]
show convincing evidence that diseases originating from humans, likely researchers studying the animals,
were responsible for significant population declines in the Taı¨ forest chimpanzees of the Ivory
Coast. On the other hand, the same study revealed evidence that research can have a protective effect
since communities less associated with research pressure were subject to heavier poaching risk. We
outline here how science based decision-making and a risk assessment approach can provide a framework
with which to investigate the trade-offs of researcher presence as it relates to human-induced disease risk.
We also provide several suggestions for future avenues of investigation and/or policy-making.

Primate crop raiding is a major cause of human-wildlife conflict around the forests of western Uganda. In an attempt to ameliorate the situation a conflict mitigation strategy was established in villages around the Budongo Forest Reserve in 2001. Live-traps were constructed that allowed the identification of crop raiding animals; pest species could be disposed of and threatened species released unharmed. However, by 2004 none of the traps in the study area were functioning and interviews were conducted to assess the reasons for their decline and local people's acceptance of the intervention. Forty-one percent of respondents did not believe the strategy was effective and the majority of local farmers did not accept responsibility for the traps. This was because of operational failures in four areas: (1) the identification of key stakeholders, (2) objective evaluation to assess the efficacy and benefit of the intervention, (3) participatory monitoring and evaluation, and (4) long-term funding commitment by conservation agencies. We examine the impact of these four elements upon the sustainability of the live-trap programme and stress the importance of recognizing and reporting failures to develop effective and acceptable mitigation strategies.

Researchers are uncovering disturbing evidence that scientists and tourists are infecting wild primates with human pathogens. In response, ape specialists, including the American Society of Primatologists, are now calling for stricter health standards for researchers and tourists. They are also urging researchers to learn how to diagnose disease in their study animals.