Domestic ungulates in protected areas and the potential for indirect interactions via shared predation

In many parts of the world, protected areas harbour permanent livestock that range freely with native herbivores. These domestic animals are typically an undesirable ecosystem component because they pose a challenge to park managers and biologists who wish to maintain ‘natural’ species interactions and diversity. Studies dealing with livestock in protected areas have primarily focussed on interactions such as competition for food resources with native herbivores, habitat degradation, and human-carnivore conflicts caused by livestock depredation. The negative effects of such interactions are a major threat to the survival of many mammalian prey and predator species. However, the role of indirect interactions between native herbivores and domestic prey, via their common enemy, has received comparatively little attention and poses a significant knowledge gap in understanding the net impacts of domestic prey on native herbivores. We present our perspectives on ignored or missed indirect interactions in livestock–native ungulate systems, and suggest some management actions for understanding these systems and minimising conflicts. A broader understanding of indirect interactions among livestock, native herbivores and their predators will aid in more informed protected-area management. Livestock in protected areas Livestock are typically an undesirable ecosystem component and pose a challenge to park managers and biologists who wish to maintain species interactions and diversity of natural systems (Das 2008; Wangchuk 2002). Nevertheless, several conservation areas around the world contain (or are next to) permanent human settlements with livestock, and in many, livestock greatly outnumber native ungulates (Mishra 1997; Tumenta et al. 2013; Li et al. 2013; Aryal et al. 2014; Schulz, Printes, and Oliveira 2014; Constant, Bell, and Hill 2015; Kuiper et al. 2015; Li et al. 2015; Sharma, Bhatnagar, and Mishra 2015; Shehzad et al. 2015). Livestock in conservation areas have a variety of negative effects on native flora and fauna (Prins 1992; Bagchi and Ritchie 2010). They may compete for food resources with native ungulates, transmit diseases, modify vegetation, and reduce the diversity and nutritional quality of forage (Mishra and Rawat 1998; Prins 2000; Bagchi, Goyal, and Sankar 2003; Bagchi, Mishra, and Bhatnagar 2004; Madhusudan 2004; Bagchi and Mishra 2006; Martin et al. 2011). We used the International Union for Conservation of Nature and Natural Resources’ (IUCN) Red List of threatened species to gain insight into how conservation organisations approach livestock. The Red List documents 129 mammalian species in protected areas that fall under the IUCN’s major threatened categories (critically endangered, vulnerable, endangered or near threatened) where the presence of livestock is considered a major threat to native diversity (IUCN 2013, Figure 1). Ninety species of large ungulates (>5 kg) are threatened by livestock populations through competition for food and habitat degradation. Out of this list, 60 face major threats that require considerable management intervention. Efforts to minimise these impacts are usually aimed at reducing contact with native herbivores, in order to minimise competition and prevent disease transmission (Kilpatrick, Gillin, and Daszak 2009). Conservation and management in systems where domestic prey coexist with large carnivores often target controlling human-carnivore conflict precipitated by carnivore predation on livestock and on humans