Wildlife may be responding to the physical presence of people much more than scientists previously understood, according to a new study that tracked more than 4,500 animals across the United States.
Researchers from the University of California, Santa Barbara, the Smithsonian’s National Zoo and Conservation Biology Institute, and Yale University combined GPS data from 37 animal species with anonymised cellphone location data.
The study, published in the journal Science, found that animals respond differently to human activity depending on the species and how much the surrounding landscape has already been changed by people.
The findings could help scientists develop more effective and species-specific approaches to wildlife conservation.
“Humans have complicated effects on wildlife — from our physical presence to how we reshape habitats,” said Ruth Oliver, an assistant professor at UCSB’s Bren School of Environmental Science & Management and co-lead author of the study.
The researchers took advantage of the COVID-19 lockdowns, when restrictions sharply changed people’s movements. This created a rare opportunity to examine the impact of human presence separately from long-term changes to the environment.
The team studied weekly GPS records of 4,581 individual mammals and birds during comparable periods in 2019 and 2020.
To measure human movement, researchers used anonymised cellphone location data with neighbourhood-level detail. They said this was the first time such data had been used to study how people’s physical presence affects animal movement.
Scott Yanco, a research ecologist at the Smithsonian’s National Zoo and another co-lead author, said the cellphone data provided a rare opportunity to measure the direct effects of human presence on wildlife.
The study found that 57% of the species examined were affected by both human presence and changes to the landscape.
Human presence was linked to changes in the territory or environmental niche of 67% of mammal species and 68% of bird species.
About 67% of mammal species and 41% of bird species reduced the amount of habitat they used when faced with a combination of human presence and landscape changes.
Animals were particularly sensitive to people in areas with relatively little development, such as national parks, compared with heavily developed cities.
However, wildlife did not respond in the same way.
Wolves, for example, expanded their habitat use in response to human presence, possibly because they tend to move farther away from people or spread out to avoid human activity.
White-tailed deer showed a different pattern. Their environmental niche expanded as landscapes became more developed but became smaller as human presence increased. Sandhill cranes showed the opposite response.
Oliver said the findings highlight the importance of developing conservation measures for individual species because animals have different habitat needs, behaviours and threats.
The research is part of the COVID-19 Bio-Logging Initiative, an international project that examined how wildlife responded to the sharp drop in human activity during pandemic lockdowns, a period researchers described as the “anthropause.”
The wider initiative involved about 600 researchers and partners and collected around 1 billion location records from nearly 13,000 animals.
The researchers said combining animal GPS tracking with human movement data can help distinguish between the effects of infrastructure and the effects of people simply being present.
They are now investigating whether changes in animal behaviour caused by human activity and climate change help wildlife adapt or instead indicate stress that could increase their risk of death.
Oliver said the findings offer hope that better policies could help humans and wildlife coexist by identifying where and when animals need more space.
Source: Science Daily