COVID-19 Lockdowns Did Not Universally Change Mammal Activity

During the COVID-19 lockdowns, streets were emptied of people, and reports began to emerge of animals appearing in city environments they would normally avoid amid the noise and bustle.

This fuelled the optimistic “nature is healing” storyline, along with ever more ridiculous memes and a wave of research examining the reported shifts in nature.

COVID-19 lockdowns and mammal activity

“I can understand why we wanted to believe that,” University of British Columbia conservation biologist Cole Burton told Lauren Leffer at Popular Science. “What animals were doing in response to people was super variable, that surprised us a bit.”

Rather than revealing a uniform response, Burton and his colleagues used the thousands of camera traps now installed worldwide to show that mammal activity rose in some locations but fell in others.

Humans present a substantial threat to most animals. Although wildlife may depend on us for resources, animals have good reason to fear people and often take considerable measures to avoid us. With 8 billion people now spread across Earth’s land, however, avoiding human activity has become increasingly challenging.

To investigate this, the researchers assessed mammal activity across more than 300,000 camera days from before and during the pandemic. Their dataset covered 102 sites in 21 predominantly European and North American countries, incorporating 5,400 camera traps.

Unexpectedly, activity in human-altered habitats increased alongside human activity, by roughly 25 percent.

“This activity was more nocturnal, suggesting that animals persisting in these developed environments may be attracted to anthropogenic resource subsidies but still seek ways to minimize encounters with people through partitioning time,” the researchers theorized in their paper.

For example, black-tailed deer (Odocoileus hemionus) became more numerous in an urban park close to Vancouver once the park reopened after lockdowns.

“This counterintuitive result was likely due to the fact that cougars, the major predator of the deer, increased when people were absent during the lockdown, but then decreased their use of the park when it reopened,” Burton told Mihai Andrei at ZME Science.

Carnivores were most sensitive to human activity

The researchers did observe that carnivores became more common as human activity declined. Separately, iNaturalist citizen-science data from 2021 showed that puma sightings in urban areas increased during the 2020 lockdowns.

Carnivores were the group most responsive to fluctuations in human activity. As people became more active, predators retreated and shifted towards more nocturnal behaviour.

“This motivates a continued emphasis on carnivore behavior and management as a key challenge for human – wildlife coexistence,” the researchers write, “given the threatened status of many carnivores, the risk of negative outcomes of human – carnivore encounters and the ecological importance of carnivores as strongly interacting species.”

Sharing space with wildlife

On the whole, Burton and the team found no worldwide, systematic change in mammal activity during the pandemic.

Their findings indicate that controlling the intensity of human activity at night in urban settings and in less-developed areas could be beneficial. Such measures could give species room for vital interactions, including predation, that support functioning ecosystems.

Yet wild places are under growing strain from popular outdoor leisure, tourism, illegal hunting and resource extraction.

As scientists have noted previously, the apparent rise in wildlife sightings near people’s homes probably happened largely because people had more time to spot animals.

Human coexistence with wildlife remains far from ideal. Amid the sixth mass extinction event, lessons from the pandemic’s continuing challenges may help us learn to share an ever more crowded planet.

After all, human wellbeing is linked to wildlife wellbeing too.

This research was published in Nature Ecology & Evolution.