Spatiotemporal resource partitioning of water sources by African carnivores on Namibian commercial farmlands

Abstract

Interspecific competition often occurs when sympatric carnivores compete for the same, limited resources, although the degree of competition between species pairs may vary with biotic factors such as body-size, diet and population density. Avoidance of dominant competitors along the axes of space and time is a potential mechanism for reducing chances of direct encounters between species. However, when resources are essential and spatially fixed, options for spatial partitioning may be limited. We examined resource partitioning within a guild of eight carnivore species at water sources across two commercial farmlands in southwest Namibia. In this semi-desert environment, surface water is scarce and farmers are forced to provision water for livestock through artificial means. Camera traps were used to record spatial and temporal activity patterns of carnivore species at artificial 2 and natural permanent water sources. We found carnivores to use either spatial or temporal resource partitioning, with temporal partitioning being most frequently seen. An association was seen between difference in body mass and degree of spatial partitioning, where species pairings with larger differences in body mass showed the greatest degree of partitioning. These results show that whilst in arid environments water is rare and used by a number of carnivore species, resource partitioning allows a guild of carnivores, including species of conservation concern, to coexist outside of protected areas.

An oasis in the desert: The potential of water sources as camera trap sites in arid environments for surveying a carnivore guild

“…Carnivore camera trap images were identified and classed into independent events as described in Edwards et al (2015). Whilst an occupancy approach may have been more suitable for such a study, the low samples sizes of some carnivore species meant models showed a poor fit to the data, therefore a comparison of relative abundance indices was used.…”

“…Whilst an occupancy approach may have been more suitable for such a study, the low samples sizes of some carnivore species meant models showed a poor fit to the data, therefore a comparison of relative abundance indices was used. Relative abundance indices for each species were calculated (Edwards et al, 2015), and were viewed as analogous to detection probabilities following Harmsen et al (2010) and Mann et al (2014). Mann-Whitney U tests were used to test for significant differences between detection probabilities produced by the water source survey design and the road survey design.…”

“…Scoutguards were programmed to take one photo per trigger, with a minute delay between triggers and set to be active 24 hours per day. A full description of camera traps placed at water sources can be found in Edwards et al (2015).…”

“…A recent study by Edwards et al (2015) showed evidence of temporal, rather than spatial partitioning to be the main mechanism promoting the avoidance of dominant competitors within a carnivore guild at water sources in an arid environment. In contrast, a large body of literature exists suggesting the preferential use of roads by apex predators and the avoidance of them by mesopredators in the presence of apex predators (Hayward and Marlow, 2014).…”

Ecology and predator associations of the northern quoll (Dasyurus hallucatus) in the Pilbara

“…Species habitat preferences can be altered depending on the level of perceived risk, including from larger predators. For example, in Tanzania, cheetahs (Acinonyx jubatus) favour heterogeneous habitats that provide refuges, allowing cheetahs to actively alter their spatio-temporal use of the landscape in response to changing densities of larger predators (Durant 1998;Edwards et al 2015). At lower densities of larger predators, cheetahs avoided lions (Panthera leo) at a fine scale, but not hyenas (Crocuta crocuta), in contrast, at higher densities, cheetahs avoided both lions and hyenas (Durant 1998).…”