Protecting Migratory Land Animals is More Complicated Than We Thought

Some species inherently know when and where to migrate, but a new study has offered a more complicated perspective for land animals by providing the first solid evidence that they need to learn about seasonal migrations from each other.

After bighorn sheep were wiped out by hunting and disease across the West in the early 1900s, efforts were launched to relocate animals to restore herds to the landscape where they once roamed. While new herds were successfully established, something odd happened. According to a study just published in the journal Science, those who were brought in failed to migrate.

“The pattern was striking,” said the study’s lead author Brett Jesmer, a doctoral student at the University of Wyoming (UW). “Detailed GPS data revealed that fewer than 9 percent of translocated animals migrated, but 65 to 100 percent of animals migrated in herds that had never been lost.”

According to the study’s authors, newcomers failed to migrate because they were entirely unfamiliar with their new homes, unlike others who had been around for decades and passed down knowledge about where and when to find the best food over multiple generations.

That cultural knowledge allowed them to ‘surf green waves’ of the most nutritious food as new sprouts emerged across the landscape in the spring taking them to higher elevations and back again.

Unfortunately, newcomers were at a complete loss, and scientists found it takes them a really long time to figure it out. To see exactly how long, they also used GPS collars to track 267 bighorn sheep and 189 moose in groups that included both those who had been relocated, and those who had been in their home for decades.

They found that it took nearly 40 years for reintroduced bighorn sheep herds to become 80 percent migratory, while moose generally didn’t become migratory until after spending about 90 years in a new habitat.

Their findings put things into a new perspective when it comes to protecting both migratory animals and the corridors they need to travel. Preserving populations is more than a numbers game, it’s about keeping that cultural knowledge intact, and ensuring individuals can continue to pass it on.

As the authors note, their work is also unique in looking at the quality of habitat as a physical landscape, and combining that with the knowledge the animals there have on how to best use it to survive. Otherwise seemingly prime habitat isn’t going to make a good home if the animals don’t know where anything is. Even when it’s ideal, they’re not going to thrive there.

It’s also going to become increasingly important to understand this issue in the face of how their environments are being altered by climate change and increasingly developed by us.

“When migration corridors are lost, we also lose all the knowledge animals had about how to make those journeys, which will likely take many decades or even a century to relearn,” said Matthew Kauffman, a researcher with the U.S. Geological Survey’s Wyoming Cooperative Fish and Wildlife Research Unit at UW. “This study clearly indicates that the best way to conserve migration corridors is to protect the landscapes that these corridors depend on today, which also will maintain the cultural knowledge that helps sustain abundant herds.”

This study is part of a growing body of migration discoveries coming out of Wyoming, a lot of which will be put together in “Wild Migrations: Atlas of Wyoming’s Ungulates,” due out this October, which details all of the state’s ungulate migrations, in addition to an online database that makes migration data widely available to interested stakeholders.

Photo credit: Thinkstock

43 comments

Jack Y
Jack Yyesterday

thanks

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Jack Y
Jack Yyesterday

thanks

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John J
John Jyesterday

Thank you

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John J
John Jyesterday

Thank you

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Marija M
Marija M5 months ago

Interesting, tks for sharing.

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Camilla V
Camilla Vaga5 months ago

thx

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Clare O'Beara
Clare O'Beara5 months ago

th

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Clare O'Beara
Clare O'Beara5 months ago

the matriarchs usually know where the good food is found.

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Clare O'Beara
Clare O'Beara5 months ago

interesting study

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michela c
michela c5 months ago

They are to be protected!

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