Hayley S. Clements

Prey Preferences of the Snow Leopard (Panthera uncia): Regional Diet Specificity Holds Global Significance for Conservation

The endangered snow leopard is a large felid that is distributed over 1.83 million km2 globally. Throughout its range it relies on a limited number of prey species in some of the most inhospitable landscapes on the planet where high rates of human persecution exist for both predator and prey. We reviewed 14 published and 11 unpublished studies pertaining to snow leopard diet throughout its range. We calculated prey consumption in terms of frequency of occurrence and biomass consumed based on 1696 analysed scats from throughout the snow leopards range. Prey biomass consumed was calculated based on the Ackermans linear correction factor. We identified four distinct physiographic and snow leopard prey type zones, using cluster analysis that had unique prey assemblages and had key prey characteristics which supported snow leopard occurrence there. Levins index showed the snow leopard had a specialized dietary niche breadth. The main prey of the snow leopard were Siberian ibex (Capra sibrica), blue sheep (Pseudois nayaur), Himalayan tahr (Hemitragus jemlahicus), argali (Ovis ammon) and marmots (Marmota spp). The significantly preferred prey species of snow leopard weighed 55±5 kg, while the preferred prey weight range of snow leopard was 36–76 kg with a significant preference for Siberian ibex and blue sheep. Our meta-analysis identified critical dietary resources for snow leopards throughout their distribution and illustrates the importance of understanding regional variation in species ecology; particularly prey species that have global implications for conservation.

An objective approach to determining the weight ranges of prey preferred by and accessible to the five large African carnivores.

Broad-scale models describing predator prey preferences serve as useful departure points for understanding predator-prey interactions at finer scales. Previous analyses used a subjective approach to identify prey weight preferences of the five large African carnivores, hence their accuracy is questionable. This study uses a segmented model of prey weight versus prey preference to objectively quantify the prey weight preferences of the five large African carnivores. Based on simulations of known predator prey preference, for prey species sample sizes above 32 the segmented model approach detects up to four known changes in prey weight preference (represented by model break-points) with high rates of detection (75% to 100% of simulations, depending on number of break-points) and accuracy (within 1.3±4.0 to 2.7±4.4 of known break-point). When applied to the five large African carnivores, using carnivore diet information from across Africa, the model detected weight ranges of prey that are preferred, killed relative to their abundance, and avoided by each carnivore. Prey in the weight ranges preferred and killed relative to their abundance are together termed “accessible prey”. Accessible prey weight ranges were found to be 14–135 kg for cheetah Acinonyx jubatus, 1–45 kg for leopard Panthera pardus, 32–632 kg for lion Panthera leo, 15–1600 kg for spotted hyaena Crocuta crocuta and 10–289 kg for wild dog Lycaon pictus. An assessment of carnivore diets throughout Africa found these accessible prey weight ranges include 88±2% (cheetah), 82±3% (leopard), 81±2% (lion), 97±2% (spotted hyaena) and 96±2% (wild dog) of kills. These descriptions of prey weight preferences therefore contribute to our understanding of the diet spectrum of the five large African carnivores. Where datasets meet the minimum sample size requirements, the segmented model approach provides a means of determining, and comparing, the prey weight range preferences of any carnivore species.

Predators on private land: broad-scale socioeconomic interactions influence large predator management

The proliferation of private land conservation areas (PLCAs) is placing increasing pressure on conservation authorities to effectively regulate their ecological management. Many PLCAs depend on tourism for income, and charismatic large mammal species are considered important for attracting international visitors. Broad-scale socioeconomic factors therefore have the potential to drive fine-scale ecological management, creating a systemic scale mismatch that can reduce long-term sustainability in cases where economic and conservation objectives are not perfectly aligned. We assessed the socioeconomic drivers and outcomes of large predator management on 71 PLCAs in South Africa. Owners of PLCAs that are stocking free-roaming large predators identified revenue generation as influencing most or all of their management decisions, and rated profit generation as a more important objective than did the owners of PLCAs that did not stock large predators. Ecotourism revenue increased with increasing lion (Panthera leo) density, which created a potential economic incentive for stocking lion at high densities. Despite this potential mismatch between economic and ecological objectives, lion densities were sustainable relative to available prey. Regional-scale policy guidelines for free-roaming lion management were ecologically sound. By contrast, policy guidelines underestimated the area required to sustain cheetah (Acinonyx jubatus), which occurred at unsustainable densities relative to available prey. Evidence of predator overstocking included predator diet supplementation and frequent reintroduction of game. We conclude that effective facilitation of conservation on private land requires consideration of the strong and not necessarily beneficial multiscale socioeconomic factors that influence private land management.

Prey morphology and predator sociality drive predator prey preferences

Predator prey preferences shape the dynamics of predator–prey assemblages. Understanding the determinants of a predators prey preferences is therefore important. Trends in prey preferences of the large African predators have been described at a species scale, limiting our ability to assess the influence of prey morphology (size and horns) and predator social structure (sex and sociality) on prey preferences. An analysis of cheetah Acinonyx jubatus kill and prey abundance information from throughout South Africa shows that the presence of prey horns and the type of cheetah social group interact with prey size to influence cheetah prey preference. The size threshold above which prey is avoided by cheetah is lower for horned prey than non-horned prey, providing evidence that horns are a predation deterrent in medium-sized prey. Horned females occur significantly more frequently in antelope species on the cusp of being too large for cheetah predation, supporting the hypothesis that horns evolved as an antipredator defense in the females of medium-sized prey. Male coalition cheetah have access to a broader weight range of prey than solitary cheetah, which may infer fitness benefits by way of expanded resource options. The prey weight range accessible to solitary male cheetah is similar to that accessible to solitary female cheetah, suggesting that, in the absence of cooperative hunting, the slightly larger size of the male cheetah infers no hunting advantage. These findings provide insight into the predation pressures driving the evolutionary selection for large body size and horns in prey, and expanded resource access leading to predator sociality.

Positives and pathologies of natural resource management on private land-conservation areas

In managed natural resource systems, such as fisheries and rangelands, there is a recognized trade-off between managing for short-term benefits and managing for longer term resilience. Management actions that stabilize ecological attributes or processes can improve productivity in the supply of ecosystem goods and services in the short term but erode system resilience at longer time scales. For example, fire suppression in rangelands can increase grass biomass initially but ultimately result in an undesirable, shrub-dominated system. Analyses of this phenomenon have focused largely on how management actions influence slow-changing biophysical system attributes (such as vegetation composition). Data on the frequency of management actions that reduce natural ecological variation on 66 private land-conservation areas (PLCAs) in South Africa were used to investigate how management actions are influenced by manager decision-making approaches, a largely ignored part of the problem. The pathology of natural resource management was evident on some PLCAs: increased focus on revenue-generation in decision making resulted in an increased frequency of actions to stabilize short-term variation in large mammal populations, which led to increased revenues from ecotourism or hunting. On many PLCAs, these management actions corresponded with a reduced focus on ecological monitoring and an increase in overstocking of game (i.e., ungulate species) and stocking of extralimitals (i.e., game species outside their historical range). Positives in natural resource management also existed. Some managers monitored slower changing ecological attributes, which resulted in less-intensive management, fewer extralimital species, and lower stocking rates. Our unique, empirical investigation of monitoring-management relationships illustrates that management decisions informed by revenue monitoring versus ecological monitoring can have opposing consequences for natural resource productivity and sustainability. Promoting management actions that maintain resilience in natural resource systems therefore requires cognizance of why managers act the way they do and how these actions can gradually shift managers toward unsustainable strategies.

The Status of Key Prey Species and the Consequences of Prey Loss for Cheetah Conservation in North and West Africa

Worldwide, decline in ungulate species abundance has a direct detrimental impact on cooccurring predator species. The objective of this chapter was to assess the conservation status of ungulates in North and West Africa, and the likely consequence for the endangered northwest African cheetah ( Acinonyx jubatus hecki) . Many of the cheetah’s prey species in this region are considered threatened or endangered, and are experiencing more rapid population declines than prey species in other areas of Africa. Key threats to cheetah prey populations are related to overharvesting and loss of habitat due to environmental changes (including land-use and climate change). The small remnant pockets of suitable habitat and available prey are unlikely to be sufficient to maintain viable cheetah populations. Improved legislative support to further conservation of key prey species and protection and strategic expansion of protected areas is crucial, requiring increased conservation funding, and broad-scale public education throughout the region.