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The migration corridors depend on the maintenance of both habitat connectivity and animal landscape knowledge, as evidenced by the migration of these American sheep to Park County, Wyo. .
Travis Zaffarano Trailcam, Wyoming Migration Initiative / University of Wyoming
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Travis Zaffarano Trailcam, Wyoming Migration Initiative / University of Wyoming
The migration corridors depend on the maintenance of both habitat connectivity and animal landscape knowledge, as evidenced by the migration of these American sheep to Park County, in the United States. Wyo.
Travis Zaffarano Trailcam, Wyoming Migration Initiative / University of Wyoming
Insects and birds may have an innate tendency to migrate at certain times and in certain directions, but a new study suggests that large mammals, such as moose and bighorn sheep, must learn to do so .
In fact, according to a report published in the journal, it takes decades for cultural knowledge about migration to accumulate before people can actually cross the land to find the best food. Science.
"If a migration is lost, a kind of disruption of the landscape that cuts off their migration, it takes a long time for these migrations to recover because they require animals to learn about their landscape, transmit this knowledge to young people. who then increase that knowledge with their own experiences and pass it on to young people, etc., "says Brett Jesmer, ecologist at the University of Wyoming." It's this very slow development of knowledge over time that is allows them to optimally use their landscape and start migrating. "
Scientists have long suspected that large mammals must learn to migrate. After all, they observed how babies follow their mother. But the idea had not been tested yet.
Jesmer and his colleagues collected GPS tracking data from 267 American sheep and 189 moose in the western United States. The researchers knew that some of these populations had been relocated in the last 60 years. mid-1800s or early 1900s because of hunting or disease.
This allowed the team to compare migration patterns of newcomers with groups of animals that had been living in their landscape for much longer, at least 200 years. "We know that they were there at the time of the Lewis and Clark expedition, and probably for hundreds, if not thousands of years before," says Jesmer.
The researchers combined information on the movements followed by animals with satellite images that showed where and when the plants were green in the landscape. Migrating flocks move up the mountains to reach the best food as it becomes available at higher altitudes, then descend as the weather cools.
When sheep were first captured in migratory populations and transferred to vacant and unknown landscapes, "they have not managed to migrate almost completely," says Jesmer.
According to the report, less than 9% of recently transferred animals migrated, compared to 65% to 100% of historical herds.
University of Wyoming researchers Matt Kauffman (right) and Kevin Monteith release a cow moose during a GPS collar migration study near Daniel, Wyo.
Mark Gocke, Wyoming Game and Fish Department
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Mark Gocke, Wyoming Game and Fish Department
University of Wyoming researchers Matt Kauffman (right) and Kevin Monteith release a cow moose during a GPS collar migration study near Daniel, Wyo.
Mark Gocke, Wyoming Game and Fish Department
"It was somehow a" Ah-ha! "It's time for me, these animals really have to learn how it all goes, where things are green and how it goes and where they should go next," says Matthew Kauffman, wildlife researcher at the US Geological Survey team.
By studying herds that have been introduced to new areas at different times over the past century, researchers have realized that it takes about 40 years for reintroduced water mouflons to develop a robust migration. Moose took about 90 years.
Other wildlife experts say the results are compelling and impressive. "The dimension they bring to the ecology of migration is the memory and cultural transmission of information," says Jacqueline Frair, wildlife ecologist at the University of Toronto. State of New York at Syracuse.
"Many simulation models have shown how migration can collapse when we start losing our leaders and knowledgeable people," says Frair. "But this article has examined it empirically from a number of different populations, with many different individuals."
According to the researchers, the most effective way to protect migratory animals is to maintain the migration corridors they currently use.
"It may take hundreds of years to build a robust migration culture," says Frair. "Once we lose the migratory populations, we may never be able to recover them given the uncertain climate and land use."
In addition, according to Kauffman, wildlife ecologists' ideas about habitat quality usually involve the study of physical features such as grass abundance. He thinks that in the future, animal knowledge on how to exploit the physical landscape should be incorporated into this assessment.
"In the American West, we have these great landscapes and many of our ungulate herds migrate through these landscapes," said Kauffman. "This study shows that what allows them to cross these great landscapes is their knowledge that has accumulated over generations."
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