Daytime sightings of elusive aardvarks hint at troubled times in the Kalahari



Disappearance of aardvarks from dry ecosystems could have devastating consequences for the many other animals that rely on their burrows.
Kelsey Green

Robyn Hetem, University of the Witwatersrand and Nora Marie Weyer, University of the Witwatersrand

Aardvarks are notoriously elusive, nocturnal mammals. They generally hide in their underground burrows during the day and emerge at night to feed exclusively on ants and termites. Aardvarks are widespread throughout most habitats of Africa south of the Sahara, except deserts. But their actual numbers are not known because they’re so elusive.

Aardvarks top the bucket list of many wildlife enthusiasts, but few have been fortunate enough to see them – until recently. Daytime sightings of aardvarks are becoming more common in the drier parts of southern Africa. But seeing them in the daytime does not bode well because it indicates they might not be finding enough food.

To understand how aardvarks cope with hot and dry conditions, we studied them in the Kalahari, one of the hottest and driest savannah regions in southern Africa in which aardvarks occur. Our study took place at Tswalu, a private reserve in South Africa that supports research through the Tswalu Foundation. We equipped wild, free-living aardvarks with biologgers (minicomputers) that remotely and continuously recorded their body temperature (an indicator of well-being in large mammals), and their activity. Each aardvark also received a radio-tracking device, allowing us to locate them regularly. Tracking the aardvarks provided clues on how they changed their behaviour in relation to environmental stressors in the different seasons and years of our three-year study.

Our study found that in drought periods, aardvarks struggled to find food. It was difficult for them to maintain their energy balance and stay warm during the cool night, so they shifted their active time to the day. Some died from starvation. Given the aardvark’s importance to ecosystems, these findings are a concern.

Comparison of Aardvarks at night and day
Aardvarks usually emerge from their burrows at night (left), but during drought periods, they are increasingly seen during daytime (right).
N. Weyer

Aardvarks are important ecosystem engineers

No other mammal in Africa digs as many large burrows as the aardvark. Dozens of mammals, birds and reptiles use aardvark burrows as shelter from extreme heat and cold, protection from predators, or a place to raise their young. In many of South Africa’s conservation areas, temperatures have already risen by 2℃ over the past 50 years. Further warming by 4-6℃ by the end of the century has been projected.

With deserts and drylands expanding across much of Africa, climate change might threaten the aardvark itself as well as the many animals reliant on aardvark burrows as a cool shelter from rising temperatures.

During typical years, aardvarks were active at night and were able to regulate their body temperature between 35-37℃.

Aardvark active at night during non-drought times
Aardvark active at night during non-drought times.
adapted from Weyer et al., 2020, Frontiers in Physiology, https://doi.org/10.3389/fphys.2020.00637

However, this pattern changed during two severe summer droughts that occurred in the Kalahari during our study. During the droughts, aardvarks shifted their activity to the daytime and their body temperature plummeted below 30°C.

Using remotely-sensed vegetation data recorded by NASA satellites and our own camera trap footage and logger data, we showed that these dramatic changes in body temperature and activity of aardvarks were related to the availability of grass, on which their ant and termite prey rely. When grass was scarce during droughts, the ant and termite prey became inaccessible to aardvarks, preventing them from meeting their daily energy requirements. As their body reserves declined, aardvarks were unable to sustain the energy costs of maintaining warm and stable body temperatures and shifted their activity to the warmer daytime.

Aardvark active in the daytime during drought
Aardvark active in the daytime during drought.
adapted from Weyer et al., 2020, Frontiers in Physiology, https://doi.org/10.3389/fphys.2020.00637

Shifting activity to the warmer daytime while food is scarce can save energy that would otherwise be spent on staying warm during cold nights. But, for our aardvarks, even these energy savings were insufficient during drought, when the ground was bare and the ant and termite prey inaccessible. As a result, seven of our twelve study aardvarks and many others died, presumably from starvation.

A bleak future for aardvarks in a hotter and drier world

On the Red List of Species of the International Union for Conservation of Nature, aardvarks are currently categorised as a species of “Least Concern”. However, we consider aardvarks to be threatened in the drier parts of their distribution in Africa, such as the Kalahari, where climate change brings about droughts. Disappearance of aardvarks from these ecosystems could have devastating consequences for the many other animals that rely on the aardvarks’ burrows.

We hope that our findings will raise further awareness about the consequences of climate change and inform future wildlife conservation and management decisions. Such steps might include assessments of the actual population status of aardvarks across Africa, or mitigation measures to preserve species that depend on burrows for refuge in regions where aardvarks might go locally extinct. More extensive measures, like water-wise reserve management, increasing sizes and connectivity of nature reserves in semi-arid regions, and reducing emissions to mitigate climate change, are just as urgent.

Finally, any solution to the plight of climate change on free-living animals requires a better understanding of their capacities to cope with drought. Therefore, many more long-term comprehensive studies are needed on the physiology and behaviour of the vulnerable animals living in hot, arid regions of the world.

Nora Marie Weyer’s disclosure statement has been updated.The Conversation

Robyn Hetem, Senior Lecturer, University of the Witwatersrand and Nora Marie Weyer, PhD – Wildlife Conservation Physiology, University of the Witwatersrand

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fires shaped Mount Kilimanjaro’s unique environment. Now they threaten it



Fires on Kilimanjaro, October 2020.
Thomas Becker/picture alliance via Getty Images

Andreas Hemp, Bayreuth University

In October, firefighters in Tanzania had to tackle a number of fires on Mount Kilimanjaro, Africa’s tallest mountain and the largest free-standing mountain in the world. The mountain and surrounding forests fall into Kilimanjaro National Park, named a UNESCO World Heritage site in 1987. Andreas Hemp provides a glimpse into the mountain’s natural environment and the challenges it faces.

Is this the first time there has been a fire of this magnitude? If there have been fires like this before, what damage was done to the mountain’s vegetation and how long did it take it to recover?

Fires are quite common in the higher areas of Kilimanjaro at the end of the dry seasons, around February to March and September to October. Fire can transform land cover, but it also maintains it. Studies that I’ve done with colleagues (using pollen records buried in the soil that go back 50,000 years) showed that fires always played a role in shaping the vegetation belts on the mountain.

For instance, certain species, such as the giant groundsels (Dendrosenecio) became fire-adapted. Also, without fires opening up the forests many light demanding species, such as the famous giant lobelias, would not be able to grow.

There have, however, been several severe fires on Kilimanjaro over the last few decades that have dramatically changed land cover.

Fires in 1996 and 1997 – years with unusually dry seasons – destroyed vast areas of old cloud forest. These are characteristically moist forests in high altitude areas which create unique environments. The forest was replaced by bush. Vegetation has started to recover and shrubs have sprouted, but it’s far from being a forest, which would take at least 100 years to grow without fire. Since these old forests have an important function of fog water collection, the loss of these forests means a serious impact on the water balance of the mountain, much larger than the impact of the melting glaciers, which is ecologically negligible.

The impact of these former fires was much bigger than that of the recent one, which “only” affected bush land and not forest.

What type of vegetation exists on Mt Kilimanjaro and how unique is it?

Due to its enormous height, Kilimanjaro has several distinct vegetation belts.

It is surrounded on the foothills by cultivation with a unique mix of agriculture, savanna and forest. This harbours very rich biodiversity as well as the tallest trees on the continent.

Higher up the mountain – between about 1,800 and 3,000 metres – a montane forest belt encircles the whole mountain. This is one of the largest forest blocks in East Africa.

Even higher up, between 3,000 and 4,000 metres, there’s a heathland belt typical of the high mountains in East Africa. This vegetation consists of Erica, Protea, Stoebe and many other shrub species, many of them are endemic, occurring only on one or several mountains.

Erica shrubs burn very easily, which makes this vegetation belt particularly flammable. During wet periods without fire, the former forest can re-establish and expand to the tree line at 4000m. During dry periods, with recurring fires (natural and or caused by people), the forest belt shrinks and the ericaceous belt expands.

What challenges does the mountain’s natural environment face and have there been any noticeable changes over the years?

Over the last 150 years, the regional climate has become drier. This has caused the mountain’s glaciers to shrink by almost 90% of their former extent. The drier climate is also the reason for an increase in the frequency and intensity of wild fires in the upper areas of Kilimanjaro, affecting the forests.

Most of these fires are lit by people (such as honey collectors smoking out bees), but these fires would not have been so devastating if the climate was wetter.

There’s an interplay between direct anthropogenic (caused by people) and climatic impacts.

Since 1911 the human population on Kilimanjaro has increased from 100,000 to over 1.2 million. This has resulted in an enormous loss of natural vegetation. Kilimanjaro is becoming an ecological island, isolated and surrounded by agriculture. Over this period it has lost 50% of its forest cover. In the lower areas this is mainly due to logging and clearing. In the upper areas it’s due to fires.

In combination with global climate change, this forest destruction results in a decrease of moisture in the region. This will also affect agriculture in the region because it’s partly irrigated.

Who is responsible for protecting the mountain and how well protected is it?

In 2005, the forest belt was incorporated into the mountain’s existing national park area. This means that it falls under the responsibility of the Tanzania and Kilimanjaro National Park authorities. The forest belt is much better protected than it was before, as a forest reserve.

The banning of camp fires on the tourist routes by the national park authorities helped to reduce the fire risk. But it’s not possible to exclude the risk in this large heathland belt totally. Perhaps the acquisition of larger fire-fighting airplanes could help. Fires are usually fought by hundreds of volunteers and firefighters, using shovels and machetes creating fire breaks by hand. This recent fire was the first time that a helicopter was used to carry water from nearby dams.

What else can be done?

To protect the biodiversity of Kilimanjaro the unique forests of the larger deep river valleys below the National Park should be incorporated into the National Park. Kilimanjaro is becoming an ecological island completely isolated and surrounded by agriculture. This inhibits the exchange of animal populations and affects biodiversity.

It’s all the more important that the wildlife corridor connecting the Amboseli ecosystem in Kenya and Kilimanjaro National Park has to be well protected. It is under great pressure due to grazing and agriculture. This corridor is important for the migration of elephants, which stay now more and more on Kilimanjaro destroying the forest.The Conversation

Andreas Hemp, Research Associate Plant Systematics, Bayreuth University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Planning a road trip in a pandemic? 11 tips for before you leave, on the road and when you arrive



Shutterstock

Thea van de Mortel, Griffith University

As restrictions ease around the country and the prospect of travel beckons, many of us will be planning road trips for the holiday season.

To ensure your trip is memorable in the best rather than the worst way, here are some things you and your fellow travellers can do to reduce the risk of becoming infected with, or spreading, COVID on your trip.

Before you go

1. Check for any travel or other COVID-specific restrictions or rules in the areas you will be travelling through or to, before you go. These can change rapidly and may include restrictions on how far you can travel, how many people per square metre are allowed in public spaces, and whether you need border passes or to wear a mask. Each state or territory has its own health department or government COVID website you can check.

2. Don’t take COVID with you. If anyone in your group has COVID-like symptoms, however mild, it is important to be tested and cleared for COVID before leaving. Common symptoms may include fever or chills, muscle aches, sore throat, cough, runny nose, difficulty breathing, new loss of taste or smell, and vomiting or diarrhoea.

3. Pack masks, disinfectant wipes and hand sanitiser. The two most likely ways of catching COVID are inhaling viral particles an infected person sheds when they cough, sneeze, laugh, talk or breathe; and ingesting particles by touching contaminated objects and then touching your face or food. Masks (and social distancing) can help reduce the former risk, while avoiding touching your face, frequent hand hygiene and cleaning surfaces can reduce the latter. So pack masks, wipes and hand sanitiser. Hand sanitiser should contain at least 60% alcohol.

4. Pack your own pillows and linen. We know people infected with SARS-CoV-2, the virus that causes COVID, can shed virus onto linen and pillows (and other surfaces), even when asymptomatic. We also know respiratory viruses can penetrate pillow covers and get into the microfibre stuffing. So you might want to consider bringing your own pillows and linen.

On your trip

5. Use disinfectant wipes to clean high-touch surfaces in your hire car. These would include door and window handles or buttons, light switches, seat adjuster controls, radio controls, the steering wheel, glove box button, gear/drive and handbrake levers, rear-view mirrors and mirror controls.

6. How about singing in the car? The more vigorous the activity, the greater the opportunity to release droplets and aerosols and the further these will travel. So, laughing and singing will release more of these than talking, and talking will release more than breathing. However, if you are travelling in a family group, or with your housemates, then you have been in close contact with one another at home and the additional risk would be low.




Read more:
This video shows just how easily COVID-19 could spread when people sing together


7. Maintain social distancing at service stations. Leave at least 1.5 metres between you and the next person while paying for fuel, ordering food and when using the bathroom. Make sure you wash or sanitise your hands after touching surfaces such as petrol pumps, door handles, bathroom taps, and before getting back in your car.

Filling car up with petrol at service station
Wash or sanitise your hands after using the petrol pump.
Shutterstock

8. Pay with cards rather than cash to avoid touching money. Many people can handle bills and coins over a long duration of time, providing many opportunities to transfer disease-causing microbes from one person to the next. Using contactless payment also helps maintain social distancing.

9. It’s safer to eat outdoors than indoors if stopping for a snack or lunch. That’s because large volumes of air dilute the density of viral particles in the air. Evidence from a study of COVID clusters in Japan suggests the chance of transmitting COVID is more than 18 times higher inside than outside.




Read more:
How to stay safe in restaurants and cafes


When you arrive

10. Is your hotel or rented accommodation COVID-safe? Ask the accommodation provider what steps they have taken to make the place less conducive to spreading COVID. For example, have they introduced extra cleaning or disinfection?

11. Use disinfectant wipes in rented accommodation to clean high-touch surfaces such as door handles, light switches, cupboard handles, taps and toilet flush buttons. You can also put dishes and cutlery through the dishwasher on a hot cycle. This is because the virus can remain viable (able to cause infection) on surfaces for many days.

Following these simple steps can help to keep your trip memorable in the best possible way. Happy holidays!The Conversation

Thea van de Mortel, Professor, Nursing and Deputy Head (Learning & Teaching), School of Nursing and Midwifery, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.