A study in Science analyzed 11.8 million GPS points from more than 4,500 animals. It found that more than 65% of species changed their movement patterns in response to human presence.
Wildlife doesn't just respond to habitat destruction, urbanization, or agriculture. New research shows that the mere presence of humans in an area also changes the way animals use space. In some cases, they reduce their range of motion. In other cases, they actually expand it, likely to avoid encountering humans or exploit food sources associated with them.
The study was published in the journal Science. It was led by researchers from the Yale Center for Biodiversity and Global Change. The team of researchers collaborated with more than 50 academic institutions and government agencies in the United States and abroad. Over six years, they analyzed the movements of thousands of animals. The goal was to separate two factors that are often examined together: physical modification of the environment by humans, and the direct presence of humans in the field.
Millions of GPS points and mobile phone data
The researchers tracked 37 species of animals in the United States. The list included 22 species of birds and 15 species of mammals. The mammals included elk, wolves, coyotes, raccoons, skunks, and some of the big cats. The birds included large birds such as eagles, hawks, ducks, cranes, and storks.
In total, about 11.8 million location points were collected from more than 4,500 animals. The researchers combined this data with mobile phone data, which was used to estimate the presence of humans in different areas. They also added satellite data on landscape changes, such as urbanization, agriculture, and land-use changes.
The COVID-19 period provided researchers with a rare opportunity. The lockdowns sharply changed human movement patterns between 2019 and 2020. This allowed researchers to examine what happens when human presence changes in a short time, without the entire physical landscape changing at the same speed.
Ruth Oliver, a former postdoctoral researcher at Yale and now a professor at the University of California, Santa Barbara, said that until now it has been difficult to measure the impact of human presence on wildlife. She said the availability of mobile device data has made it possible for the first time to examine this impact on a large scale.
Not all species react the same way.
The study findings showed that more than 65% of species changed their behavior in response to human presence. The effect was particularly strong in natural and less developed areas. In other words, precisely in places where nature appears to be relatively preserved, the mere entry of humans into the area may change animal behavior.
The responses were not uniform. Many species reduced the space in which they moved. They may have done this to reduce the chance of encountering humans. In contrast, other species expanded their range of movement. Gray wolves, for example, moved over larger areas. The researchers estimate that they may have done this to bypass areas where humans were present. Crows also expanded their movement, probably because they know how to exploit food sources associated with human activity. Coyotes, on the other hand, tended to reduce their movement.
The study also found flexibility in individual animals. Animals were able to change their behavior patterns from year to year. This shows that they are not just responding to fixed conditions in the environment. They are able to adapt to changes in human activity patterns.
A new meaning for nature conservation
Professor Walter Jetz, director of the Yale Center for Biodiversity and Global Change, said habitat loss remains a major factor in the loss of BiodiversityHowever, the study shows that humans' direct use of the landscape also affects animals. He says animals may change their behavior in ways that exacerbate or reduce the impact of habitat loss.
The practical conclusion is thatNature conservation It cannot be satisfied with just protecting open spaces. It must also address the question of when people enter the area, to what extent, and in what manner. For example, there may be a need to restrict movement during sensitive periods, reduce vehicle access to certain areas, or more carefully manage recreational activities in nature reserves.
Scott Janko, also a postdoctoral researcher at Yale and now a researcher at the Smithsonian's National Zoo's Conservation Biology Institute, said the technologies used in the study allow us to see in unprecedented detail just how diverse wildlife responses to human activity are. He said that's why conservation strategies also need to be targeted. A one-size-fits-all solution for all species and all regions won't be enough.
The study highlights that humans don't just change nature when they build, pave, or cultivate land. Walking on a trail, driving an SUV, or engaging in recreational activities in a natural area can also affect animals. In an era when human pressure on open spaces is increasing, this distinction is especially important. It may help create a more accurate balance between human presence in nature and the need to protect the animals that live there.
Quick FAQ:
What did the new study examine?
The study examined how the presence of humans and landscape changes affect the movement of birds and mammals in the United States.
How many animals were included in the study?
The researchers analyzed approximately 11.8 million GPS points from more than 4,500 animals.
What is the main finding?
More than 65% of species have changed their behavior in response to human presence, even when the habitat itself has not changed.
For the scientific article: DOI 10.1126/science.adq3396
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