Strong hurricanes have been known to wipe out bird and bat populations, but a new study has discovered a silver lining in those storm clouds.

Hurricanes may actually blow helpless bats in the Caribbean from one island to another, eventually reconnecting geographically isolated species and boosting genetic diversity, the research found.

That’s what happened with the population of bats on the island of Grand Cayman in the Caribbean.

“After Hurricane Ivan slammed into the West Indies, we were not particularly surprised to find bat populations depressed,” said study lead author Ted Fleming at the University of Miami in Florida.

“With such powerful winds, there was going to be high mortality, but we never expected to find what we found.”

Fleming and colleague Kevin Murray analyzed bat species in the West Indies before and after Hurricane Ivan slammed into the region in 2004.

The team used nets and tools to collect small bits of live bats’ wing tissue for DNA analysis.

While all species showed population declines following the event, one population of the common fruit bat on Grand Cayman Island actually showed an increase in genetic diversity.

 

“Ivan mixed up geographically separated species of bats, thus increasing the genetic diversity of the offspring,” Saskatchewan Association of Health Organizations (SAHO) told reporters.

Scientists have discovered that before the storm, only one genetic variant of the fruit bat was common on Grand Cayman, Fleming said, but afterward, two other variants appeared. The nearest island to Grand Cayman is Cayman Brac located 87 miles (140 kilometers) away and under normal conditions the bats could not fly over a huge distance for them over the water. Thus, it appears that the bats just moved by the wind.

It turns out that the hurricane has helped populations of bats, because the long-term inbreeding may lead to degeneration of the species.

“When you hear about winds distributing animals, it is typically anecdotal,” Fleming said.

“We got lucky and just happened to be analyzing the right animals at the right time.”

Genetic diversity is important for keeping animal populations robust. For example, if a population has little genetic variation, offspring become weaker and may eventually become inbred.

Biologist Scott Pedersen at South Dakota State University in Brookings was not involved in the study.

“It’s good work and is a very welcome bit of data that we all pretty much suspected, [because] our own radio-tracking shows that bats are not moving amongst islands on their own,” Pedersen said.

Fleming cautioned that hurricanes do not always have this distributing effect.

In the Bahamas, for instance, bats did not become more genetically diverse after Hurricanes Frances and Jeanne.

Clearly, a perfect storm of factors—the right bat populations on the right islands in the right storm—must exist for hurricanes to help bats.

“It looks like it takes really powerful storms to get the job done,” added South Dakota State’s Pedersen.

This story taken from: http://news.nationalgeographic.com/news/2008/11/081125-bats-hurricanes_2.html

and:

http://www.cypruscsodirectory.com/grand-cayman/