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It’s not everyday that you come across someone whose study has to do with those small dark shapes we see flying at night or hanging upside down from tall beams or branches… It was for this reason that we were particularly interested in tracking down Theresa Laverty, who as part of her PHD has focused on understanding how bats, some of the world’s smallest mammals, relate to the largest mammals on our continent (more of which she explains to us below).
Theresa Laverty untangles a Roberts's flat-headed bat from a mist net set over a borehole near Hoanib Skeleton Coast Camp. Photograph by Lisette Gelber
Theresa, who hails from Ocean City in New Jersey, a small barrier island along the Atlantic Coast of America, is not an easy person to find. This is because on an average day when we are sitting in our office, Theresa is somewhere in the great Namib Desert in her research truck where she spends her days and nights. This is home except for a few days every month when she makes the drive to Windhoek, to restock on food and catch up on computer work.
But this arrangement suits her perfectly; “I have never been a huge fan of big cities after growing up in one of the most densely populated states in the US. Despite the relatively large population of Windhoek, Namibia's capital city has never felt too big.” Theresa’s studies are currently based out of Colorado State University's Department of Fish, Wildlife, and Conservation Biology in Fort Collins, Colorado (USA).
When we found out about Theresa, we were intrigued – what makes someone pack their bags and move to Africa to a remote desert to study bats? How did she find herself here, and what has her study revealed so far?
These are the questions that we simply had to ask…
Why bats? What was it that led you to study them?
I had never worked with bats before beginning my Ph.D. The previous research projects with which I had been involved focused on large mammals like African elephants and mountain gorillas in East Africa and reptiles like the caiman species of the Peruvian Amazon. I chose to work with bats because as nocturnal, flying mammals, we know very little about their basic biology and distribution in comparison to larger, more charismatic species. All that we know about bats in Namibia before this year stems from sporadic museum collection surveys dating back to the 1930s. Given their recognised importance as seed dispersers, pollinators, and insect pest controllers, understanding how communities of some of the world's smallest mammals (i.e. bats) relate to some of the world's largest mammals (e.g. elephants, rhinos, and giraffe) could provide important insights into desert food webs and our conservation actions.
How long have you been doing research in Namibia and was there any particular reason why you choose the country and specific location?
I conducted a pilot research season in December 2014 and January 2015 before returning to Namibia in January 2016. I should be in the country for approximately another year of data collection.
The Namib Desert is not only considered to be one of the world's oldest deserts, but its northern portion in Namibia (i.e. the Kunene Region) is also home to one of the most diverse desert communities of large herbivores, such as elephants, black rhino, Angolan giraffe, and a rich suite of smaller herbivores. Almost all life in deserts concentrates around their limiting resource – water. Very little, however, is known about the bat communities in the area, which use water for drinking and foraging opportunities. My PhD supervisor, Dr. Joel Berger, pointed me toward this area as he had worked in northwestern Namibia on a black rhino study approximately 25 years ago.
Two desert elephant families convene at water just before sunset on the Hoanib River a few kilometers east of Skeleton Coast National Park, Namibia. Photograph by Theresa Laverty
Can you tell us a bit about the study you are doing and what you hope to achieve?
I am particularly interested in how bat communities in northwestern Namibia may relate to large herbivore communities. Given their large body size, megaherbivores can have huge individual impacts on vegetation communities around rare aboveground water, which could have strong effects on a variety of other animals. Changes in vegetation can impact insect communities, which would affect insectivores like bats. Dung piles may accumulate particularly near water and raise local insect abundance, attracting insectivores like bats. Lastly, species like elephants can dramatically change vegetation structure and thus change the accessibility of an area for bats species that are less maneuverable fliers. With my project, I hope to understand the roles of threatened large herbivorous species like elephants and black rhinos on very distantly-related bat communities.
Have there been any interesting insights into bat behaviour that you have discovered so far?
The first thing that comes to mind is that bats continue drinking water while elephants are watering at night. Twice, I have had an elephant bull sneak up on me at night, leaving me unable to pack up my equipment before backing off. Thankfully, the bulls have left my equipment alone, but each time I returned to a plethora of bats in the net.
Additionally, it seems like seasonal bat migrations do occur throughout the region. For instance, I captured three African straw-coloured fruit bats last month for the first time ever. This species typically resides in the tropical forests and savannas of central and southern Africa.
An elephant bull waters on the opposite side of a mist net on the Hoanib River. Photograph by Lisette Gelber.
Where are you based?
I work over approximately 20 natural springs and boreholes along several of the ephemeral river systems in the Kunene Region. I re-net for bats at the same sites each month, so I'm usually moving my campsite each day. I've worked as far south as Gai-Ais Spring below the Huab River and as far north as Ougams Spring between Puros and Orupembe. All my sites receive on average 100 mm of rainfall or less.
What does a normal day in the field look like for you?
I work with Lina, a Masters Student at the University of Namibia, who is also studying bats in the area. We tend to get up around sunrise and pack up camp before the day gets too hot. We then typically begin making our way to our next field site. Soon we will be integrating vegetation surveys and large mammal dung transects into our morning routine. Upon arriving at our field site, we take a quick look at the spring or borehole to look for recent animal signs and investigate water conditions for netting. We then drive to a nearby site and relax (hopefully in the shade) for hottest part of the day. Just before sunset, we arrive back at our site and set up a mist net for capturing bats and a bat detector for recording the ultrasonic call activity of bats. We also test the water quality and will be soon setting up insect traps nearby. For three hours, we remain at the site and untangle bats as they fly into the net. We take morphological measurements and release the bats while also recording their calls. After our three hours are up, we pack up and drive off to set up camp away from the spring or borehole.
Roberts's flat-headed bat awaits untangling from a mist net at sunset on the Hoabib River. Photograph by Theresa Laverty.
What is your relationship with Hoanib Skeleton Coast Camp?
I spend a few nights a month at Hoanib Camp. Lina and I give a short presentation to the guests after they return from Möwe Bay that day. When netting at the borehole in front of Hoanib Camp, we invite guests to join us when we are processing bats. Some nights, we are busy at Hoanib Camp and are happy to share the experience with anyone who cares to join us after sunset. Other nights, we may only catch one bat, but we always welcome questions and company.
An elephant bull demonstrates the effects of its species on vegetation structure. Photograph by Theresa Laverty.
The best thing about living and working in Namibia?
I have met a lot of helpful, friendly people through my project (including many of the staff at Hoanib Camp), and have had some incredible opportunities to explore Namibia's beautiful, arid landscape. Each month comes with new challenges, but there are also new surprises like spotting a rhino cow and her approximately one month old calf last month. It is also great working in an area with such dedicated conservationists and in a country where most people still relate to and value their wildlife. Plus doing my research under the Namibian night sky is incredible thanks to the remoteness of the area.