Based on my previous blog “Aardvark as ecosystem engineers“, I thought it would be good to dive into a species which relies on Aardvarks, to a certain extent…

This blog is going to focus on my thesis which I completed, summarizing an 80-page document into one page could be a challenge, but hopefully, I include everything.

A family of warthogs spin and run off across a clearing. These cute piglets have only just appeared from their burrows and have stolen the hearts of many visitors!

Study Aims and Objectives:

Previous scientific literature has shown the distribution of the common warthog throughout Africa, however, no empirical data on covariates/variables that influence warthog occupancy have been identified. Additionally, these distributions have changed over time due to anthropogenic factors, such as land-use change, habitat destruction, agricultural expansion, and climate change. Literature has also shown that warthogs are predominately in regions where aardvarks are present, although warthogs have also been seen in regions where aardvarks are not present. The study significance delves into the covariates that influence warthog occupancy at a reserve level. This allows for a better understanding of the covariates that influence warthog occupancy.

A warthog scurries down a termite mound late one afternoon. Warthogs are diurnal meaning that at night they seek refuge in burrows to stay out of harm’s way. They normally use holes in termite mounds.

Introduction:

Species important in regulating ecosystem composition, diversity and functioning are called keystone species. Keystone species are similar to ecosystem engineers, which are capable of physical modification to abiotic and biotic materials, increasing resource availability for other species. Therefore, it is important to consider keystone species to reduce the potential knock-down effect on species reliant on these modified ecosystems and species that maintain these systems.

Warthog is a species that often utilises aardvark burrows as they do not have the anatomical features that allow them to construct their own. Burrows have numerous characteristics that allow for shelter, buffered microclimate, protection against predation and an environment where species can rear their young.

Therefore, warthogs often rely on abandoned burrows or other forms of geographic structures for survival and reproduction. However, it is not known which factors warthog are dependent on, or to what extent. Additionally, in some regions, warthogs are not dependent on aardvark activity, especially in areas where warthogs occur at altitudes where aardvarks are absent.

Warthog in burrow

Brief methods:

The study focused on two protected areas in South Africa, Atherstone Nature Reserve and Mountain Zebra National Park. Data collection was part of a continuous research project called Snapshot Safari South Africa. A combination of 38 camera traps over a five-year period was used to gather images of warthog to analyse the presence or absence of the species at the respective reserves. My hypothesis considered a range of factors such as the presence of aardvark, the presence of predators, vegetation type, soil composition, distance to perennial water sources, proximity to roads, distance to the nearest 10 trees (tree cover at site level), and camera efficiency, was tested using occupancy modelling with camera trap data from Atherstone Private Game Reserve and Mountain Zebra National Park.

Three newly born warthog piglets cuddle near their mother at the opening of a burrow. These little guys are only three or so weeks old at this stage.

Summarised results:

Notably, the positive impact of aardvark presence on both warthog occupancy and detection underscores the facilitation capabilities of aardvarks in promoting co-existence. Aardvark burrows emerged as shelters, providing a suitable environment and protection against predation and environmental conditions. The presence of predators, especially lion and leopard, exhibited a discernible negative effect on warthog occupancy, likely attributable to the heightened predation risk posed by these ambush predators, which wait outside burrows and often dig warthog out from within.

Moreover, the positive correlation between the distance to water and warthog occupancy underscores the species’’ dependence on perennial water sources throughout the year for thermoregulation and metabolic requirements. Conversely, increased tree cover at the camera site level had a negative influence on warthog occupancy, aligning with regional vegetation types, as more densely covered areas proved less suitable for foraging while increasing predation risk. Furthermore, tree cover exhibited both positive and negative effects on warthog detection probability, highlighting the complexity of this relationship.

“An absolutely insane display of power and persistence as we watched the Nweti Male dig at a termite mound for 45 minutes before erupting from the burrow with this massive warthog in his jaws. The cloud of dust surrounding them perfectly captured this incredible moment – raw strength and determination in action. Without a doubt my most incredible sighting of the year, and one that shows just how powerful these cats really are.”

These covariates mentioned in the results also impacted the detection probability of warthog at both study sites, highlighting the complexity of the factors influencing their occupancy. The understanding gained from this study emphasises the significance of considering multiple variables to predict and manage warthog populations, particularly as the effects of climate change on the environment will shape the species distribution. The findings underscore the importance of ongoing research, incorporating additional covariates, to refine our understanding of the multifaceted influences on species (warthog) occupancy to improve effective management and conservation.