Rhinos are mega-herbivores who significantly alter the habitat around them and thus affect large numbers of other organisms this is known as a keystone species.
Rhino poaching started more than a decade ago and lots of time, money, and even lives have been given to this crisis, and yet rhino numbers are still in decline. So are rhinos worth all the effort?
While there is the obvious answer that their decimation is completely a man-made issue due to greed and corruption and therefore we are morally obligated to try and protect and save them, there are ecological reasons too.
As we learn more about how intricate nature is and how humanity really does depend completely on nature on the one hand but also at nature’s mercy on the other (Covid), it is in our best interest to protect the complete balance of biodiversity.
Ecological reason 1
Rhinos love to wallow in mud and in doing so they create small water holes which over time will expand into larger ones. But they will keep creating small ones that are perfect to get a good cover of mud on the skin. This network of small water holes allows smaller animals and birds to drink safely away from predators that will stalk out larger water holes.
The mud that sticks to them also dries and falls off as they walk around. This clay-based soil will be richer in nutrients than the common sandy soils of the bush and this helps distribute some important micro-nutrients for plants.
This action is termed geoforming and some studies have shown that rhinos impact their habitats more than elephants.
Ecological reason 2
Rhinos eat a lot. They are also hindgut fermenters which means they do not fully digest all their food. With eating about 50kg of vegetation per day they deposit more than 20kg of dung much of it still recognisable plants. Females wander around their home ranges depositing dung and males wander around their territories, creating dung middens’ (spots that are habitually used for defecation) as a territorial marking mechanism (scent from urine and dung can provide a lot of information to a rhino!).
This dung fertilises the soil and provides shelter, food, and a mini-ecosystem for many other species. Many insects will come and use the dung but the most famous are the dung beetles of which there are many species. They try to get in as quick as possible to secure the best dung, where they shape it into a ball and roll it away in haste. They will then lay their eggs in the dung and bury it. These in turn are routed out by small animals like mongoose who eat the developing larvae. Birds and small mammals too will search through the dung looking for both insects and seeds and so rhino dung starts the basis of many a food chain within the African bush.
Ecological reason 3
Rhinos, like all wildlife in the bush, are hosts to ticks. These ticks feed other species such as Oxpeckers and even terrapins (which may come and remove ticks from rhino that lie in shallow water). Rhino tends to constantly have Oxpeckers due to the ticks. However, this symbiotic relationship between these two species has also given the rhino a warning system. Rhinos love to sleep during the hot part of the day and while they rest the Oxpeckers will remove ticks and also lookout for any danger. The rhino will awaken immediately if he hears the Oxpeckers calling for danger.
Rhinos also suffer from ectoparasites – rhino fly or tabanid fly. These flies score the flanks of a rhino which look like sore patches or stripes which can be seen through binoculars. They spend a large part of their lifecycle in the stomach of the rhino, and their existence is so tightly bound to that of rhinos that their numbers decline sharply when rhino numbers decline. Oxpeckers will also feed on the flies but they also like the taste of blood and can keep wounds open just to keep a regular supply of blood!
Ecological reason 4
White rhinos are bulk grazers and have the nick-name of lawn-mowers of the bush. Their broad flat mouth is able to crop the grass very low. This encourages certain grass species to grow which helps develop short grazing areas. Certain plants are only able to survive in these areas such as short annual grasses which can’t naturally compete against perennial grass species. These areas are important for antelope such as wildebeest and birds such as longclaws, larks, and pipits. The patchwork of grazing lawns also helps diversify habitats in the areas and increases biodiversity. These rhino lawns also become safe spots during veld fires as there is only short fresh grass that is not easily combustible which are important for slow-moving species such as tortoises and for plant species that cannot tolerate fire.
Ecological reason 5
The rhino is one of the iconic “Big Five”, which includes elephant, buffalo, lion, and leopard, and forms the wish list of many international and national tourists for wildlife sightings in the bush. The white rhinos in particular are easy to see in South Africa and therefore play a vital role in monetising ecosystems through tourism. The money that comes through tourism also protects and affords the smaller and lesser-known creatures and their habitats, allowing in-tact ecosystems to exist and function which then provides people the ecosystem services that we all rely upon such as water and clean air.
Rhinos from an ecological perspective are what’s called ‘keystone species’. This is a species whose presence and role within an ecosystem has a disproportionate effect on other organisms within the system. That is why it is critical that we not only save rhinos because of our moral duty but also because rhinos are important within their own ecosystems to the other plants and animals.