Friday, November 17, 2017

How Animals and Plants Weather Hurricanes


Studies suggest not all critters fare well in extreme weather, though some thrive.
Hurricane Maria decimated Puerto Rico. With sustained winds of 155 miles per hour, much of the US territory has been without power for weeks. Many residents lack running water, hospitals have been limping along on backup generators, and the island’s agriculture has been essentially flattened. The toll on local wildlife remains far from appreciated, but it’s clear from Maria and other hurricanes that some animal populations suffer from big storms—while others thrive.

Endangered animals are of paramount concern to conservation biologists. When a few key deer (Odocoileus virginianus clavium) were spotted on Big Pine Key in Florida after Hurricane Irma swept through, it prompted a sigh of relief. Likewise in Puerto Rico, one native islander, the endangered Puerto Rican parrot (Amazona vittata), seems to have fared “surprisingly well” after Maria, Fish and Wildlife Service (FWS) spokesman Mark Davis tells The Scientist.

Vibrant and vocal, these birds are rare in the wild. A. vittata were first listed as critically endangered in 1968, with their numbers dipping to 13 in less than a decade. Since then, conservationists have been working tirelessly, breeding the birds in captivity and releasing them into the wild, to boost their numbers. In 1989, 47 individuals flitted about the island, with at least 12 forming breeding pairs.

Then, Hurricane Hugo hit that year, ravaging the island and the birds. The population fell to just 22. It rebounded and then again, devastating storms in 2015 stripped the forest of food and the birds’ numbers plummeted. Now, Hurricane Maria has marked the island, but the birds’ numbers, at least those in captivity, seem to be stable. Damage to the aviaries caused the death of a few birds, probably from heat or the stress of being moved to different cages, Michelle Eversen, a biologist and program coordinator for FWS in the southeast U.S. and Caribbean, wrote to Davis. In the wild, “we don’t know how many survived or if they are having difficulty finding food after the storm,” Eversen reported. But researchers working with the captive birds have seen wild Puerto Rican parrots near two of the aviaries on the island—a hopeful sign.

Strategies to survive
Not all birds have been so lucky. A masked booby, probably blown off course as Hurricane Jose worked its way up from the tropics in September, landed on the shores of Massachusetts recently. Workers at Wild Care Cape Cod, a wildlife rehabilitation facility in Eastham, tried to take care of the bird, but it was reported dead October 3.

Birds, like us and other animals, take a few different strategies in the face of storms. Some leave before it hits. They can sense drops in barometric pressure, so they know when to go. Others fly straight into a storm, though tracking birds with satellite tags has shown that the success of that strategy is mixed. Still other birds, such as the Puerto Rican parrots, shelter in place. What researchers don’t yet know is how well these tactics work.

“There aren’t a huge number of studies about what animals do in hurricanes,” says biologist Helen Bailey of the University of Maryland Center for Environmental Science. The studies don’t exist because they are hard to do; surveying animals in extreme weather isn’t really realistic.

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