Changing Planet

Return to the World’s Oldest Desert (and Its Bats!)

Desert-adapted black rhinos can go up to three days without water, so it is particularly important to give them some space around springs. (Photo by Theresa Laverty)
Desert-adapted black rhinos can go up to three days without water, so it is particularly important not to disturb them around springs. (Photo by Theresa Laverty)

A mega-adrenaline rush

My eyes strain to see beyond the flashlight’s beam in hopes of identifying the animal responsible for those faint footsteps I’m hearing. Perhaps it is just those three Hartmann’s mountain zebra that were on the ridgeline moments ago, or the sound of my chest rising and falling beneath my light down jacket, I try to convince myself. However, I find it difficult to relax, and keep my flashlight ready in hand.

Less than three minutes later, the torch reveals the outline of a black rhino making its way around a blind corner. I immediately go to start the bakkie (the term used for pick-up trucks in Namibia), but all I hear is “click.”

Escape options begin racing through my head. The cliff is nearby and likely safe, given rhinos have notoriously bad eyesight (unlike bats), but I would prefer to keep that as a backup plan. With a dying primary battery and the need for a jump from my secondary battery tucked away in the back of the bakkie, I holler out a light “hey, hey, hey” and watch as the young bull moves slowly away from me. He is cautious, yet thirsty, and so he likely lingers in the area.

Fresh black rhino tracks are a common sighting across parts of the Kunene Region of northwestern Namibia. (Photo by Theresa Laverty)
Fresh black rhino tracks are a common sighting across parts of the Kunene Region of northwestern Namibia. (Photo by Theresa Laverty)

Five minutes is all I need, however, to get back on the road with all of my field equipment in tow. It was another safe escape tonight and I can make up those last 15 minutes of fieldwork another day. At least I caught a few bats in the earlier evening hours. Three miles away, my nerves calm as I set up camp on a rocky hilltop. It surely is never a boring day in the field.

The world’s oldest desert

Not many people spend their evenings sitting around remote desert springs. Even less opt to do so in one of the world’s oldest deserts. Due to the nocturnal behavior of bats, however, I find myself by desert springs most nights this year. In the northern Namib Desert, along the Atlantic coast of Namibia, desert-adapted megaherbivores—elephants, black rhinos, and giraffe—and large carnivores like lions still roam free and heavily rely on such areas for water and/or food.

There is nothing quite like a pitch-black evening around a desert’s scarcest resource (water), typically located at least half-a-day’s drive from the nearest settlement, to remind you why most of us humans are diurnal — active during the day.

Desert springs come in different shapes and sizes and vary in vegetation cover within Namibia's ephemeral river systems. Almost all wildlife concentrates around these rare, limiting resources. (Photo by Theresa Laverty)
Desert springs come in many shapes and sizes. They also vary in vegetative cover along Namibia’s ephemeral river systems. Almost all wildlife concentrates around this rare, limiting resource. (Photo by Theresa Laverty)

All in the name of research (and a degree)

As a refresher, I am studying desert bats in northwestern Namibia for my Ph.D. dissertation research. I am specifically interested in the local drivers of insectivorous bat community diversity. I survey bats over desert water sources—springs and boreholes (manmade pools like wells)—along the region’s highly ephemeral river systems. Despite desert adaptations, bats still lose a lot of their water weight each day in arid climates. Therefore, they rely on rare, aboveground water bodies for both drinking and/or foraging opportunities.

The Egyptian free-tailed bat (Tadarida aegyptiaca) is one of at least 15 species of bats that has been captured thus far through Theresa’s study. (Photo by Theresa Laverty)

Some of the questions I aim to address with my study include: Are bats targeting specific water bodies in search of certain minerals or water quality characteristics? Are they simply following changes in local insect abundance (i.e. their primary food source) across the landscape? Or are there more complicated interactions occurring between different food chain levels? For instance, higher elephant densities may remove more vegetation and provide better access to water for less maneuverable bat species. Additionally, increases in large herbivore dung densities may relate to greater insect abundances and thus affect the bat activity at a site.

Author Theresa Laverty (left) and Lina Mushabati (right) pose with a migrating African straw-colored fruit bat captured in June. (Photo by Joel Berger)
Author Theresa Laverty (left) and Lina Mushabati (right) pose with an African straw-colored fruit bat (Eidolon helvum) migrating through desert northwestern Namibia in June. (Photo by Joel Berger)

I am currently working in Namibia for about another year, collecting the majority of my data. For 2016, I have teamed up with Lina Mushabati, an M.Sc. student at the University of Namibia, who is also studying bats in the area. I look forward to sharing more updates from the field and insights on our research as the year progresses. Thanks for following along!

My name is Theresa Laverty, and I am a PhD candidate in Colorado State University's Department of Fish, Wildlife, and Conservation Biology. I study the community ecology surrounding desert water sources in Namibia. More specifically, I examine how large mammalian herbivores, via their direct and indirect effects on vegetation and insect communities around rare, aboveground water bodies, could impact bat communities that prey on insects. My research takes place along the ephemeral desert rivers of the northwest, where elephants, giraffe, black rhinos, and many smaller herbivores live among the livestock of traditional pastoralists. I hope you enjoy reading my posts from the field!

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