In human-populated landscapes, dogs (Canis familiaris) are often the most abundant terrestrial carnivore. However, dogs can significantly disrupt or modify intact ecosystems well beyond the areas occupied by people. Few studies have directly quantified the environmental or economic effects of free-roaming and feral dogs. Here, we review wildlife-dog interactions and provide a case study that focuses on interactions documented from our research in Mongolia to underscore the need for studies designed to best determine how dogs affect native wildlife and especially imperiled populations. We suggest additional research, public awareness campaigns, and the exclusion of dogs from critical wildlife habitat. The application of scientific findings to management and enhanced public outreach programs will not only facilitate recovery and maintenance of wildlife populations globally but also has the potential to reduce economic losses.
Estimating the density or abundance of mountain ungulates is difficult and rarely conducted in a statistically valid manner. The rough terrain they inhabit, their group-living habits, their relatively low density, and the difficulty of marking individuals all contribute to making rigorous estimates of abundance logistically difficult. Raw (uncalibrated) counts are usually reported, and although their drawbacks are often acknowledged, biases are rarely quantified. In September 2009, we took advantage of the presence of a radio-marked sample of argali Ovis ammon in the Ikh Nart Nature Reserve in south-central Mongolia, as well as the area's comparatively forgiving topography to estimate abundance simultaneously using two independent methods: distance sampling and mark-resight sampling. Distance sampling produced an abundance estimate of 539 (95% CI: 196-1,081) argali within a ; 330 km 2 study area on the same day that we visually tallied 189 animals. Mark-resight sampling using the Poisson log-normal model yielded an estimate of 747 (95% CI: 484-1,009) argali when we observed, at most, 223 animals in any given day. Although both were imprecise, their similarity increases our confidence that neither estimator was highly biased. Because of budget or logistical restrictions, uncalibrated counts of mountain ungulates are often the only alternative. They should be viewed cautiously, however, and when possible, more rigorous approaches to estimating abundance should be taken.
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.
We examined variables that might affect survivorship of neonatal argali sheep (Ovis ammon), including body weight, date of birth, gender, precipitation, and year affects, which often influence neonatal survivorship in other species of sheep. From 2003 to 2008 we handcaptured 75 argali lambs (38(, 36&, 1 undetermined) and attached expandable, drop-off radio collars in Ikh Nart Nature Reserve, Mongolia. We collected morphometric and physiological measurements and radiotracked lambs to obtain data on survivorship and mortality. We found similar morphometric and physiological measurements for male and female lambs, with significant differences only in foreleg length (&-() and respiration rates (&)(). Only 44.6% of argali lambs survive their first month of life, but thereafter their mortality rate decreases. Lambs not born in 2006, born in years following years with higher April precipitation, and born later in the year enjoyed significantly higher survival to one month. We found high mortality in the years with severe drought (2005)(2006), which depressed overall survivorship. We found no significant effect of any physiological or morphometric variables on lamb survival. Argali lambs die from several causes, with predation (44.6%) and starvation (21.4%) being the most significant.
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