The Gardeners of the Night
When the sun sets over Africa, the palm fruit bats awaken. Hundreds of thousands of them leave their sleeping trees and fly through the darkness in search of ripe fruit, sweet nectar and flowering trees. What appears to be a ghostly spectacle is in fact one of the most important services an animal can provide for its habitat.
Palm fruit bats are flying gardeners. They pollinate flowers that no one else can reach and spread seeds over dozens of kilometres – far more effectively than any bird. Without them, many African forests would slowly become impoverished, cease to regenerate and fall silent. Ecologists estimate that a single fruit bat can spread the seeds of up to 60,000 trees per night.
One particularly spectacular event takes place every November in Kasanka National Park in Zambia: up to a million palm fruit bats gather there in a few groups of trees – the largest mammal migration in Africa. No one knows why they choose this particular place or what drives them there.
And this is not an isolated case. We know alarmingly little about these animals. Where exactly do they migrate to? How are their colonies connected? What routes do they take when the dry season causes their traditional feeding grounds to dry up?
This lack of knowledge has consequences. Palm fruit bats are hunted for bush meat or driven away in many regions because they are considered pests. Yet they give humans far more than they take. They are also considered potential carriers of pathogens – which is precisely why it is so important to understand where they live and with whom they come into contact.
The Animal, Nature and Species Conservation Foundation therefore supports research into palm fruit bats as part of the ICARUS project. Tiny satellite transmitters are being used to track their nocturnal migrations for the first time – across the continent, even to the most remote regions. The data shows where they rest, where they feed and what dangers they encounter.
This creates an image that offers double protection: for the flying foxes themselves, whose ecological importance is finally becoming apparent, and for us humans, who are learning how closely our fate is intertwined with that of these nocturnal gardeners.
Source: Prof. Dr. Martin Wikelski, Uschi Müller, www.icarus.mpg.de