To The Bat… Pond?

Desert foxes and desert rats, leave a few sips for the desert bats. A study in Israel’s Negev Desert finds that even small temporary ponds may be critical to the survival of bats living in arid regions. The liquid insight highlights the importance of conserving desert ponds of all sizes, the authors say.

Dozens of bat species have colonized arid and semi-arid lands around the world. Biologists, however, know relatively little about how these flying mammals cope with the sometimes extreme stresses imposed by such parched landscapes. Some species have evolved physiological methods of conserving water, such concentrating their urine. Still, all bats have to drink, and they typically swoop down on rivers and lakes to sip on the fly. Three Israeli scientists wondered, however, just how the size and duration of desert water bodies might shape bat behavior.

To find out, the researchers – from Ben-Gurion University of the Negev and the Ramon Science Centre – held monthly nighttime stakeouts at 10 ponds in the Matsok HaZinim Nature Reserve in the Central Negev Desert in 2007 and 2008. Most of the ponds dried up in the summer, but some were big enough to hold water nearly year-round. Using cameras and audio detectors, they recorded bat activity over the ponds, watching as the bats sipped from the surface and plucked insects out of the air. They even covered parts of several large ponds with plastic, in a bid to see how a suddenly smaller pool affected bat behavior.

Overall, the team recorded 10 of the 12 species known to live in the region, they report in Animal Conservation. Some came to ponds only to drink, while others were more interested in foraging. In general, more maneuverable bats could tap smaller ponds, while clumsier species needed bigger “swoop zones.” Overall, they found that bigger, higher-volume ponds supported more kinds of bats, and more bat activity. But the pond’s “hydroperiod” — temporary or permanent – didn’t make much difference.

The results highlight the importance of ponds of all shapes and sizes to desert wildlife, the authors write. But they also suggest that conservation efforts “should focus on larger temporary ponds (over 15 meters in length and 0.5 meters in depth) because they support similar bat species richness and activity levels as permanent ponds, but are less likely to be protected due to their ephemeral nature.” David Malakoff | Ocotber 1, 2010

Source: Razgour, O., Korine, C., & Saltz, D. (2010). Pond characteristics as determinants of species diversity and community composition in desert bats Animal Conservation, 13 (5), 505-513 DOI: 10.1111/j.1469-1795.2010.00371.x

Image © Vladimir Khirman