*4.2. Waterholes and Ephemeral Mud Wallows*

The waterholes had a high mammal species richness in total (21 species), but separately, each waterhole had low species richness and diversity (Table 3). This total number can probably be higher since the smaller and nocturnal mammals might have been missed because of the way the camera traps were set up to cover the entire waterhole and some of the surrounding area. Sutherland et al. [20] reported 26 mammal species at the same three waterholes but also including an additional fourth waterhole during a similar time period. They indicated that carnivores and small herbivores were observed during the night at these four waterholes, while large herbivores and primates visited mostly during the day. Some species, such as elephants and large predators, may monopolise water sources and prevent other species from drinking [5]. This was not observed during the short period of this study, as large numbers and a variety of mammal species were observed at the waterholes, even at the peak of the drought. The three permanent waterholes are located on granitic soils in close vicinity to the study area. They constantly provided drinking water in the drought, since they are filled with underground water by solar pumps and windmills, while ephemeral areas dried up at the beginning of the dry season.

Common species found at the catena were also captured at the waterholes (Figure 1 and Table 2). The black and white rhino were captured at some of the waterholes, but this information is classified. Results from Sutherland et al. [20] correspond roughly to results from this study, i.e., they found an average of 6–7 species at De la Porte for the dry and wet seasons; 3–8 species at Kwaggaspan; and 10–11 species at Renosterkoppies waterholes (compare to Table 2). It is interesting that they reported total numbers of 3 for blue wildebeest, 5 for hippo and 1 warthog that correspond exactly with group sizes observed in this current study. They also listed 3 grey duiker, 2 leopards, 7 scrub hares and 5 side-striped jackals observed in total, but these might be different events and not different individuals. These species were also noted with lower numbers in this study but mostly solitary or in pairs. Species listed by Sutherland et al. [20] that were not captured at the waterholes in this study were cheetah, black-backed jackal, honey badger, southern springhare, steenbok, serval, large spotted genet and white-tailed mongoose that were all captured during the dark part of the night. Some of these species listed were found at the catena or granite outcrops (Figure 1), and only the first four species were completely absent from our results. It is not mentioned at which waterhole these animals were captured, and it may be that these species are present at the N'waswitshaka waterhole included by these authors or that we did not record them during the night.

Based on number of events (Table 2), blue wildebeest, impala and greater kudu seemed to prefer Renosterkoppies waterhole which is the nearest to the catena studied (3.3 km in a straight line), while plains zebra was only captured at the Kwaggaspan waterhole (4.6 km in straight line). Hippopotamuses depend on water-related landscapes but are also known to graze several kilometres from water [18,22,31]. In the study area, hippos were observed quite far from the perennial water sources (i.e., the closest point to the Sabi River is 13.2 km in a straight line) and were found in the drainage line (riparian zone) (Figure 1) and at two of the nearest waterholes only during 2016 at the peak of the drought. Elephant are also known to occur 15–24 km from water in drought conditions [31]. Hippo was captured in 2016 at the De la Porte waterhole, which was the furthest from the catena studied, namely 6.2 km in a straight line, while waterbuck only occurred at the Kwaggaspan waterhole during 2017 at the end of the drought. These latter two species have water-related habitat requirements and are known to stay in close proximity of surface water. The grey duiker is known to be water independent and was not captured while drinking at the Kwaggaspan waterhole, it was just passing by the camera probably en route to reach specific forage patches in its territory.

Water-dependent species require water regularly and can range 5–6 km (non-mobile species: impala, bushbuck, warthog) or up to 10 km distances (mobile species: buffalo, zebra, blue wildebeest) from water [31,32]. Some of the listed species (Table 2) prefer to stay close to surface water, e.g., waterbuck, and they were not expected at the catena which is further away. Buffalo and waterbuck were found farther from surface water where lower forage quantity was available in dry years, while zebra, wildebeest, elephant and impala were found farther with lower forage quality [5,28,33,34]. In the nutrient poor granites (compared to the basalts), the quality and quantity of food are lower, and animals have to travel further from water than in basalt areas where their forage and water needs can be satisfied closer to the waterholes [27].

Irregular availability of water in semi-arid savannas can affect the distribution of mammals, together with the distribution of forage and certain habitat effects. Animals often migrate long distances in response to food and water availability [9,27,35]. In areas where permanent water is provided artificially, the significance of water as a limiting resource or as driver for migration patterns in dry periods is suppressed, as is the case in KNP [5]. If herbivores aggregate near waterholes, predators may also concentrate in the vicinity [26]. Grazers occurred closer to water than expected by Smit et al. [27], while mixed feeders and browsers occurred at high densities close to the rivers but at low densities close to waterholes. Waterbuck and elephant are very water-dependent and tend to be more associated with rivers than with artificial waterholes, while buffalo were found to use both rivers and waterholes. Rivers provide water, habitat and forage to these species [27]. The three waterholes are less than 6 km from the centre of the study area and the closest point to the perennial Sabi River is 13.2 km from the study area, so the area is still within reach of many of the water-dependent species, especially the more mobile species. According to Smit and Grant [5] (p. 69), "An increase in distance to the closest water source implies higher costs in terms of energy spent during travelling, as well as energy "not gained" due to time spent travelling instead of foraging." Additionally, they also state that a larger distance travelled may increase the chances of encountering predators and increase calf mortality due to exhaustion.

The distance to permanent water sources together with many other factors plays a role in the use of ephemeral sources by a mammal species, including the number of animals that can be supported by the ephemeral source, quality and accessibility of the water, other specific conditions that can be limiting and the period of time that the source contains water [31]. Ephemeral water source location depends on the topography and geology of an ecosystem together with rainfall fluctuations in that area. These water sources differ over a range of temporal scales, from small pans or mud wallows formed by rainstorms during the dry season that only contain water for a few days or weeks to pools formed in seasonal rivers that are available throughout the dry season [31,34].

Mud wallows in the study area are located on the sodic patch (with shallow rock beds) and in the riparian area. It contained water during the 2015 and 2016 survey periods but not during 2017. Mud wallows are depressions (small pans) in the ground that temporarily fill with rainwater, hold the water for a certain period thereafter and are maintained by wallowing of animals [15]. These wallows were favoured by species that cover their bodies with mud (i.e., buffalo, elephant, warthog, black and white rhino), while most of the mammals also quenched their thirst at the larger temporary holes on the catena (15 species in total were observed using mud wallows).

Other authors found that herbivores dissipate in KNP and use waterholes less after the first rains when pans and other ephemeral depressions fill with water [20,36]. This enables animals to use areas slightly further away from permanent water. If cover and forage are abundant, animals will probably stay close to the perennial water sources and minimize predation risk by travelling to satisfy water requirements, while the scarcity of food and cover in these areas as result of drought can result in animals dispersing to areas with ephemeral water sources [31]. This will depend on the animal's body size and water dependence. Redfern et al. [31] hypothesized that the distribution of large and mobile water dependent herbivores will be more influenced by ephemeral water sources than perennial sources, while distribution of smaller herbivores that have a fixed territory or specific water related habitat requirements will be limited by perennial water sources.

#### *4.3. Feeding Guild and Body Size*

Foraging commonly makes up the largest portion of an animal's mobile activity, especially for large mammals, and basically determines their space occupation [30]. The mammals listed in this study were therefor divided into two main categories, namely, feeding guild and body size. Activity patterns of the mammals observed during the study period were covered in another study [15].

Different feeding guilds were represented in the data, from herbivores to carnivores, scavengers (i.e., jackal, hyena, etc.), insectivores and omnivores (Table 1). These different feeding guilds can indicate a working ecosystem on the catena, especially if it can be linked to different habitats in the zones that include certain biotic and abiotic factors of the catena ecosystem. Herbivores were subdivided into the following dietary classes: grazers that feed mostly on grass and herbaceous material; browsers that feed mostly on leaf material from woody plants, including the concentrate selectors (steenbok and duiker) that select the more nutritious plant parts and fruit; mixed feeders that feed on grass and browse material; and general vegetarians that feed on plant material, such as roots, geophytes, bark, fruits, nuts, etc. Insectivores that feed mostly on insects such as ants, termites and other invertebrates; and omnivores (feed on plant and animal material) [22,37] were also noted.

The order Carnivora contains predators, scavengers and animals that also include large proportions of insects in their diet, such as civet, genet, banded mongoose, dwarf mongoose, slender mongoose and white-tailed mongoose found in this study. Few species are strictly carnivorous; most supplement their diet with fruits, bone, carrion, insects and other invertebrates making it difficult to group them into insectivores, omnivores or carnivores [22]. The majority of predators use the resource 'live prey', but it can be classified into various prey classes with the following characteristics: prey type, size, sex, age, activity periods and habitat needs [38]. Ambush predators (lion and leopard) prefer to hunt in areas with more cover and they are usually more successful during the night [26]. Cursorial predators (wild dog and hyena) need more open areas to run the prey down to exhaustion and then kill it. Some predators (serval, jackal) specialize in rodents and birds and use pouncing and jumping techniques to hunt [22]. All of these carnivores were present in the study area but not limited to specific zones.

Mammalian herbivores that feed on different plant types and parts can optimally utilize the diversity in vegetation resources in the same space [37]. Selective preferences for specific food resource types can generally be expressed by the herbivore either staying in profitable areas for longer times and/or by returning frequently to such areas [26]. Interspecific competition mostly occurs in the dry season when adequate quality forage becomes depleted due to most plants being dormant [28].

Mammal species that are less common generally specialize on a narrow range of resource types, while species that are more abundant usually exploit a wider range of resource types and habitat conditions, according to the niche breadth concepts [3]. Du Toit [8] and Macandza et al. [39] list several authors that describe the various scales at which distinctions in habitat occupation (presence or absence of mammal species) can be recognized, from landscape or biome to vegetation types, habitat to plant species composition of local patches and specific plant parts. Animal factors such as social and behavioural aspects, home range sizes, high- or low-density species, water-dependence, predation, age, sex, among others, also play a role in areas occupied [15]. At landscape scale, some features of resource heterogeneity include vegetation structure of woody plants, soil fertility, distance to water, topography, geomorphology, etc. [39]. Thus, according to Macandza et al. [39] (p. 176), "coexistence among large herbivores may be enabled by

distinctions in resource use at one or more of these scales, underlain by differences in body size and morphological adaptations".

A large variety and range in body sizes were indicated in Table 1, from the smallest ruminant antelope, the steenbok (0.5 m shoulder height, 11 kg), to the largest land mammal, the elephant (4 m, 5000 kg), is present in the study area, spanning three orders of magnitude in body mass [8], while carnivores range from dwarf mongoose (0.07 m, 0.27 kg) to lion (1.2 m, 190 kg). There are various mechanisms that regulate food intake that can be connected to body size. Small herbivores usually require less feeding time, and they can spend relatively more time to search for higher quality food items, giving them a patchy distribution. Larger herbivores need to maintain their intake when forage is limited (quantity) and may be forced to consume a lower quality diet resulting in a more even distribution over larger areas in general [10,31,40]. Small mammal distribution may be influenced more by location of cover than distribution of larger species [31], but they may competitively displace the larger guild members away from feeding sites in a horizontal plane for grazers and vertical plane for browsers [8]. However, distribution of large and small species may actually overlap in areas that are resource rich [28,40]. The granite landscape is not nutrient rich compared to other areas in the KNP and only the sodic patch, drainage lines and termite mounds [19] have more nutritious vegetation than the surrounding study area (as explained earlier), but still a variety of mammal species and body sizes were recorded. These species may occupy the same local area because they use different food sources at different heights (based on their body size, morphological and digestive adaptations), and they are not limited to this area only, since they can include other areas in the larger landscape (distribution differences) at different times to meet their nutritional needs and so reduce competition.
