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In arid regions of the developing world, pastoralists and livestock commonly inhabit protected areas, resulting in human–wildlife conflict. Conflict is inextricably linked to the ecological processes shaping relationships between pastoralists and native herbivores and carnivores. To elucidate relationships underpinning human–wildlife conflict, we synthesized 15 years of ecological and ethnographic data from Ikh Nart Nature Reserve in Mongolia's Gobi steppe. The density of argali (Ovis ammon), the world's largest wild sheep, at Ikh Nart was among the highest in Mongolia, yet livestock were >90% of ungulate biomass and dogs >90% of large-carnivore biomass. For argali, pastoral activities decreased food availability, increased mortality from dog predation, and potentially increased disease risk. Isotope analyses indicated that livestock accounted for >50% of the diet of the majority of gray wolves (Canis lupus) and up to 90% of diet in 25% of sampled wolves (n = 8). Livestock composed at least 96% of ungulate prey in the single wolf pack for which we collected species-specific prey data. Interviews with pastoralists indicated that wolves annually killed 1–4% of Ikh Nart's livestock, and pastoralists killed wolves in retribution. Pastoralists reduced wolf survival by killing them, but their livestock were an abundant food source for wolves. Consequently, wolf density appeared to be largely decoupled from argali density, and pastoralists had indirect effects on argali that could be negative if pastoralists increased wolf density (apparent competition) or positive if pastoralists decreased wolf predation (apparent facilitation). Ikh Nart's argali population was stable despite these threats, but livestock are increasingly dominant numerically and functionally relative to argali. To support both native wildlife and pastoral livelihoods, we suggest training dogs to not kill argali, community insurance against livestock losses to wolves, reintroducing key native prey species to hotspots of human–wolf conflict, and developing incentives for pastoralists to reduce livestock density.

Summary 1. Testosterone has emerged as an important mechanism linking variation in male reproductive behaviour to parasite infection in vertebrates, and there are numerous pathways by which testosterone can influence infection risk, particularly in free-living animals. 2. The immunocompetence handicap hypothesis posits that the positive effects of testosterone on sexual signalling and behaviour are traded off with negative effects on immune function. While this obligate trade-off may sometimes explain the association between testosterone and parasite infection, testosterone–parasite relationships may also be mediated by correlated changes in stress, condition and exposure to parasites. 3. In this study, we explored associations between testosterone and reproductive behaviour, immune function and parasitism in free-living Grant’s gazelle (Nanger granti). In particular, we examined how stress (glucocorticoids), behaviour and condition might mediate associations between testosterone, immunity and parasitism. 4. We found that variation in endogenous testosterone in male gazelle was correlated with mating behaviour in terms of sexual signal intensity (horn size) and resource-holding potential (territoriality). We also showed that these same levels of testosterone were associated with immunity and parasite infection, but associations between testosterone, immunity and parasitism were complex. Testosterone was negatively associated with adaptive immunity, but positively associated with innate immunity. Relationships between testosterone and parasitism varied for different parasites. 5. Our results suggest that the effects of testosterone on male immunity are not universally suppressive and that immunoenhancement may also occur. In addition, testosterone–parasite relationships vary depending on the parasite, most likely due to the opposing effects of testosterone on different aspects of immunity and indirect effects on parasite exposure mediated by changes in behaviour.

We evaluated four factors that may influence the process of male natal dispersal in wild female-philopatric blue monkeys: aggressive eviction by adults, attraction to oestrous females, social integration in the natal group and survivorship risk. Observations of nine males and five females of dispersal age allowed us to compare the social behaviour of males and females and that of dispersing and nondispersing males. We also studied the circumstances of 26 natal dispersals (1997–2006). Aggressive eviction did not appear to be important in most dispersals. We found no significant differences in rates or types of aggression received by juvenile females and males or by dispersing and nondispersing males. Sexual attraction also did not appear to influence dispersal, because males did not disperse more often than expected by chance during conception seasons or during breeding-season influxes of males. Our results confirm low social integration as a correlate of sex-biased dispersal. Juvenile males groomed and sat in contact with groupmates significantly less than females did, although we found few differences between dispersing and nondispersing males. Our results also suggest that males timed dispersals to minimize risks, because dispersal was most likely to occur during months of low rainfall and least likely to occur when fruit was least available. Endogenous factors are probably important in stimulating dispersal, because all males disperse but females never do. Although aggressive eviction may occasionally influence the dispersal process in blue monkeys, given their unimale group structure, our results implicate social integration much more uniformly and strongly.