Las tecnologias de la informacion y comunicación y el sentido unido a la

Leopards have the widest distribution of all large cats in Africa and yet, their habits and feeding ecology outside of savannah habitats are still poorly understood (Martins et al., 2011; Jooste et al., 2013). Although leopards have a broad dietary niche (Hayward and Kerley, 2008), it is known that carnivore populations are generally limited by their food supply (Macdonald, 1983). Hayward et al. (2007a) found leopard density was strongly correlated with preferred prey biomass. In addition, Chase Grey et al. (2013) suggested that the probable high abundance of bushbuck, a preferred species of prey for leopards at Lajuma, may account for the high density of leopards found there. However, neither this reason nor others that were hypothesised, have been formally tested. As potential prey species in the Soutpansberg

Mountains range from <10 kg to species >60 kg, it will be interesting to determine the prey preferences of leopards in this area and see if they concur more with those of Martins et al. (2011) where leopards in a similar mountainous environment mostly consumed prey less than 20 kg, or with studies done in other habitats where the mean prey weight was typically larger. Leopards in the Soutpansberg Mountains have fewer carnivore competitors than populations which co-exist with other large felid species. Thus, it will also be interesting to see if diets of the leopards here are different due to the lack of inter-specific competition for prey.

Knowledge of any predator’s diet is crucial for their management (Hayward et al., 2007b) thus, this study employed a combination of dietary analysis and prey availability analysis to determine what prey species are available and consumed by leopards in the Soutpansberg Mountains. Prey availability governs the movements, abundance and population viability of large carnivores (Hayward et al., 2007a), hence, it was hoped that the investigation of leopard diet would provide insights into possible explanations for the high density of leopards in this region. A large prey base of species from a variety of taxa and a range of different sizes

43 would provide a wide choice of prey for leopards to hunt, regardless of their hunting

preferences. This variety of available prey, if found in the scats and on the camera traps, would indicate that the environment has sufficient prey to support a high density of leopards A diet profile of the leopard was described using scat analysis, the identification and

quantification of undigested materials that have passed through the digestive systems of the species of interest (Trites and Joy, 2005). Scat analysis has become the primary method of assessing carnivore diets (Klare et al., 2011) due to the ease of collecting samples and its non- invasive nature, compared to more intrusive methods such as analysing stomach contents. The frequency of occurrence of each prey species among scat collections can be easily determined to describe the average diet of leopards (Trites and Joy, 2005). A comparison study by Klare et al. (2011) found that frequency of occurrence methods were used in 94% of reviewed papers, and were the sole method used in 50% of the papers. Although frequency of occurrence indicates how common an item is in the diet, Klare et al. (2011) concluded that it has the least ecological significance and can provide misleading results about a species’ ecology. This is due to the surface to volume issue that occurs when prey sizes are highly variable, creating a tendency for frequency of occurrence estimates to overestimate the number of smaller species consumed and underestimate the number of larger species (Henschel et al., 2005). Due to the relatively greater surface area in relation to volume in smaller prey types their, often complete, consumption results in the production of more scats containing indigestible material, such as hair, than larger prey types where mostly just meat, and relatively little hair, is consumed. Therefore, smaller prey items have a greater

representation in scats per unit ingested than larger prey (Floyd et al., 1978). Here, scat contents were quantified using both estimates of frequency of occurrence and relative biomass consumed. Calculating the percentages of food items in the diet of leopards is an essential element in understanding the role they play in this montane environment, as well as the impacts they may have on prey populations and local farming communities.

Prey availability was determined using camera trap images, a method which had yet to be used in the Soutpansberg. Conducting game count surveys has previously been the most common method for estimating prey abundance for comparison with diet, with techniques such as aerial counts (Hayward et al., 2006; Jooste et al., 2013) or road transects (Hunter, 1998; Walker, 1999; Balme et al., 2007) being used. However, these studies are often limited by the surveyor’s visibility (Hunter, 1998), a disadvantage that is overcome by the use of

44 camera traps. Previous studies often use camera trap data as a measure of abundance (Balme et al., 2010; Henschel et al., 2011). However, as noted by Cutler and Swann (1999), a number of photos is rarely an index of abundance as it is usually impossible to determine whether multiple photos represent repeated events from one individual or single events from various individuals. Furthermore, the number of photos obtained depends on the movement

behaviour of the focal species and, thus, cannot be compared among species. Here, instead of assuming that the number of independent capture events is proportional to abundance, the more realistic assumption is made that it is proportional to the probability of encounter. By using this encounter rate, rather than relative abundance rate, in combination with scat data, Manly’s selectivity index (α) (Manly et al., 1972; Chesson, 1983) was evaluated for each of the main prey species. This index measures the degree to which a predator ismore likely to take one kind of prey rather than another (Manly et al., 1972) and is commonly used in the literature to determine whether a predator preys on a species more or less than expected by chance (Escamilla et al., 2000; Teixeira and Cortes, 2006; Davis et al., 2012; Klecka and Boukal, 2012). A value of α = (1/n) (where n = the total number of species), means the specific prey species is consumed in proportion to its availability in the environment, α > (1/n) indicates preference and α < (1/n) indicates avoidance (Teixeira and Cortes, 2006). This index will be valuable in determining whether leopards are preying on species they encounter regularly or have preferences in their diet.

Camera trap data were also used with scat data to produce Independent Event Rates (IERs) which provide data on the average number of independent events for a scat location for a species, based on the events at the surrounding camera stations. The IERs of a number of species were then used to explain the presence or absence of a species in a given scat, for example if the presence or absence of baboon in a scat can be explained by the event rates of baboon and other species. The purpose of using more than one species’ IER to predict occurrence in a scat is that the focal species’ abundance might be expected to affect occurrence but, equally, so might the abundances of other common species in the area be expected to reduce it.

45 4.2 Methods