Massive animal database reveals troubling climate trends in Arctic

Climate change is affecting Arctic animals at an unprecedented rate. And with these creatures' help, ecologists may be better able to tackle this monumental challenge head-on using the tools they already have at their disposal.

Movement data — collected using animal-borne sensors — are used by ecologists to understand and track animal behavior in ways pure observation just cannot do. But easily accessing these data has long been a challenge in and of itself. With such dispersed datasets, researchers were often left scrambling to understand how their observations fit in with past and other ongoing research.

But this manmade obstacle to getting the science done may become a thing of the past, thanks to a massive database containing three-decades worth of animal data. Now, the Arctic's own animals can reveal how the climate warming is really changing their world.

The database is detailed in a paper published Thursday in the journal Science.

Gil Bohrer is a co-author on the paper and professor of civil environmental and geodetic engineering at Ohio State University. He tells Inverse that the challenge of collecting data from animals creates a cascade of obstacles that has held data-sharing among scientists, back.

"It is difficult because animal movement data is hard to collect... [and] each animal research project typically involves a few (up to tens) of individual animals of 1-2 species, over 1-3 years," Bohrer explains. "[Even then,] data comes in many different formats and standards... [and] is rarely shared."

As a result, crucial data may be accidentally tucked away in a researcher's field notebook or lost when they retire, Bohrer says.

"The Archive solves all these problems," he adds. Ultimately, this could be a first step toward further uniting the data — and the conservation community.

See also: How Siberian horses became an unlikely climate hero in the arctic

The new archive, dubbed the Arctic Animal Movement Archive, is the first to include both terrestrial and marine data from the Arctic region. In total, the archive spans data collected from 1991 to the present, and includes 207 tracking studies involving more than 8,000 animals.

To build the Archive, Bohrer and his colleagues had to spend years building relationships with other scientists from national, regional, and First Nations governments. In total, the Archive contains data from more than 100 universities, government agencies, and conservation groups in 17 countries.

How to use the archive — The database is a game-changer for climate and ecology research. To understand how large an effect it could have on the field, the researchers behind the Archive outline three case studies for its use in their paper.

The first case study focuses on the migratory patterns of 900 female caribou between 2000 and 2017. The researchers compared birth times between caribou with notoriously long migrations and non-migratory, mountain or lowland woodland caribou.

From the data, the team discover migratory caribou and the northernmost non-migratory populations were giving birth earlier in the spring than other caribou in the region.

Elie Gurarie is an associate research scientist in UMD's Department of Biology and co-author of the paper. In a statement accompanying the research, she says while the drivers of this behavior are unclear, seeing these patterns helps ecologists predict how the caribou may respond to continued warming in the region.

"It's tricky to predict how these trends might impact populations," Gurarie said. "On the one hand, it can be better to give birth earlier... on the other hand, giving birth too early may mean you literally don't have time to reach the optimal calving grounds."

"These results reveal patterns that we would not have suspected, and point to further lines of inquiry about everything from caribou evolution to their ability to adapt to environmental changes moving forward," she added.

In the other case studies, the researchers zoom in on the migration of golden eagles, as well as the movement speed of bears, caribou, moose, and wolves. In both studies, the researchers observed subtle differences in behavior that appear to be driven by climate changes. For example, they discovered young golden eagles migrating north appear to be arriving earlier in the spring following milder winters as opposed to colder winters.

These effects are small, but they could easily snowball into substantial changes in animal behavior — such as how different species compete over food or hunt, the researchers say.

"This work has given us a baseline to understand the large-scale picture so we can get a sense of how animals and environments are really interacting across species and across space as the environment changes," Gurarie said.

More data, less problems — The researchers hope their database can be a powerful tool for ecologists, but Bohrer tells Inverse that it is still far from complete. In the future, the team hopes to design similar archives for other important regions around the globe, including the Yukon and the Yellowstone Migration corridor.

"We are limited by the amount of data we have. The Archive has a lot, but there could always be more," Bohrer says. "We hope that after publication, more and more researchers will join to participate in the Archive and share their data."

Abstract: The Arctic is entering a new ecological state, with alarming consequences for humanity. Animal-borne sensors offer a window into these changes. Although substantial animal tracking data from the Arctic and subarctic exist, most are difficult to discover and access. Here, we present the new Arctic Animal Movement Archive (AAMA), a growing collection of more than 200 standardized terrestrial and marine animal tracking studies from 1991 to the present. The AAMA supports public data discovery, preserves fundamental baseline data for the future, and facilitates efficient, collaborative data analysis. With AAMA-based case studies, we document climatic influences on the migration phenology of eagles, geographic differences in the adaptive response of caribou reproductive phenology to climate change, and species-specific changes in terrestrial mammal movement rates in response to increasing temperature.