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201714Aug16:35

Cli­mate change threat­ens Aard­varks and African species rely­ing on Aard­varks’ burrows

Infor­ma­tion
pub­lished 14 August 2017 | mod­i­fied 14 August 2017
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AardvarkThe aard­vark will become increas­ingly rare as the world warms and dries, and the con­se­quences go well beyond a decline in aard­vark safari encounters.

Accord­ing to researchers study­ing this elu­sive mam­mal, some­times classed as one of the “Shy 5”, in South Africa’s Kala­hari Desert, aard­varks prove to be highly sus­cep­ti­ble to the warmer and drier cli­mates that are pre­dicted for the west­ern parts of south­ern Africa, in the future. Dur­ing the study of a num­ber of aard­varks by researchers of the Brain Func­tion Research Group at the Uni­ver­sity of the Wit­wa­ter­srand, all but one of the study ani­mals – as well as other aard­varks in the area – died because of a severe drought, with air tem­per­a­tures much higher than nor­mal and very dry soil in the area. The study results are pub­lished on 19 July in Biol­ogy Let­ters.

While unusual now, those are the con­di­tions that cli­mate change is likely to bring as the new nor­mal,” says Pro­fes­sor Andrea Fuller, the Research Group’s director.

Dr Ben­jamin Rey stud­ied the aard­varks as part of his post­doc­toral stud­ies. Along with his col­leagues, he used the new tech­nol­ogy of “bio-​loggers” (minia­ture sen­sors attached to com­puter chips and implanted into the aard­varks by wildlife vet­eri­nar­i­ans), to study the activ­ity pat­terns and body tem­per­a­tures of aard­varks liv­ing in the Kala­hari. The researchers were not to know that dur­ing the year of their study there would be a severe drought, which led to the death of the study animals.

It is not because the aardvark’s body can’t take the heat, but that the ter­mites and ants that they rely on – not just for food but also for water – can’t take the heat and arid­ity of chang­ing climates.

Dr Ben­jamin Rey, lead-​author, Brain Func­tion Research Group, School of Phys­i­ol­ogy, Fac­ulty of Health Sci­ences, Uni­ver­sity of the Wit­wa­ter­srand, Johan­nes­burg, South Africa.


(Source: 5050 Com­mu­nity YouTube channel)

Aard­varks usu­ally sleep dur­ing the day in bur­rows that they have dug, and emerge at night, to feed on ant and ter­mites, using their long, sticky tongues to sweep up thou­sands of insects. How­ever, dur­ing the drought, the ter­mites and ants, on which the aard­vark depends for body energy, were not available.

As a result, the aard­varks’ body tem­per­a­tures fell pre­cip­i­tously at night. The aard­varks tried to com­pen­sate by shift­ing their search for ants and ter­mites from the colder night to the warmer day, so that they would not have to use energy to keep warm, but that was not enough to save their energy stores,” says Dr Robyn Hetem, a co-​worker on the study. “We believe the aard­varks starved to death.”

The aard­vark pro­gres­sively became skin­nier and bonier. They even tried sun-​basking to save energy, but many ulti­mately died. Their body tem­per­a­tures dropped to as low as 25°C just before they died.

Rey says that this curious-​looking crea­ture – described as hav­ing the snout of a pig, the ears of a rab­bit and the tail of a kan­ga­roo – is much more than just a curios­ity to be checked off a bucket list.

The aard­vark
The aard­vark (Oryc­tero­pus afer) is a medium-​sized, elu­sive bur­row­ing, pre­dom­i­nantly noc­tur­nal mam­mal native to Africa. The aard­vark is widely dis­trib­uted south of the Sahara from Sene­gal to Ethiopia to South Africa, being absent from the Sahara and Namib deserts. It is also present in the Congo Basin, although its dis­tri­b­u­tion in West African rain­forests is poorly known (Tay­lor 2013). It is the only liv­ing species of the order Tubu­li­den­tata, although other pre­his­toric species and gen­era of Tubu­li­den­tata are known. Unlike other insec­ti­vores, it has a long pig-​like snout, which is used to sniff out food. It roams over most of the south­ern two-​thirds of the African con­ti­nent, avoid­ing areas that are mainly rocky. A noc­tur­nal feeder, it sub­sists on ants and ter­mites, which it will dig out of their hills using its sharp claws and pow­er­ful legs. It also digs to cre­ate bur­rows in which to live and rear its young.
The dis­tri­b­u­tion of the aard­vark is largely deter­mined by the abun­dance and dis­tri­b­u­tion of suit­able ant and ter­mite species, which it eats. When ant and ter­mites dis­ap­pear because of cli­mate change, the aard­vark will do as well. So, the aardvark’s sur­vival may be threat­ened by cli­mate change via direct and indi­rect effects of increas­ing heat and arid­ity. It’s cur­rent con­ser­va­tion sta­tus is con­sid­ered as Least Con­cern accord­ing the IUCN Red List of Threat­ened Species, while the aard­vark pop­u­la­tion trends are not known.

Many species of African birds, mam­mals and rep­tiles use the bur­rows dug by aard­varks to escape cold and heat, to repro­duce, and to avoid preda­tors. They can’t dig these bur­rows them­selves. With­out aard­varks, they would have no refuge. Wor­ry­ingly, they could face the same fate as the aardvark.”

Cli­mate change in south­ern Africa affects ani­mals through the direct effects of increas­ing air tem­per­a­tures and arid­ity. Wild dogs, for exam­ple, reduce hunt­ing activ­ity as tem­per­a­ture increases. But the indi­rect con­se­quences of heat and arid­ity may be more per­va­sive. Dis­ap­pear­ance of aard­varks, and with them the bur­rows that they dig, will have knock-​on effects for many other animals.

Pop­u­la­tions of many ani­mals in South Africa are already declin­ing as a result of habi­tat loss and over-​exploitation,” says Fuller. “Cli­mate change adds an addi­tional threat, which may push species to extinc­tion faster. By 2050, the aard­vark may not be the only species removed from tourist checklists”.

(Source: Uni­ver­sity of the Wit­wa­ter­srand news release, 31.07.2017; Wikipedia; IUCN Red List of Threat­ened Species)


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