Featured picture: Bear and co under pressure

Black bear
(Image: University of Sydney / Judy Gallagher, Creative Commons)

This American black bear apparently devours its freshly caught prey with relish. The fact that he sometimes has to travel long distances before such a feast is mainly due to the people.

Whether climate change, deforestation or urbanization, for example: Humans are increasingly changing the habitats of many animals or are even being completely lost. Living beings have to keep pace with change in order not to starve.

In order to survive, many animals are forced to enlarge or relocate their habitats. Researchers working with Tim Doherty from the University of Sydney have now calculated how much human influences change global animal movements. To do this, they collected over 200 studies on more than 160 animal species, from insect species to various mammals, and analyzed to what extent and how humans influence the movement of animals.

The result: In around 70 percent of the animals examined, human activity increased by more than half. Reductions in movements were less common at around 37 percent. With some animals, such as the black bear (Ursus americanus) in our photo, there is both enlarged and reduced movement spaces depending on the season.

The research team found that particularly seasonal events such as hunting, military and recreational activities influenced the behavior of the animals. For example, badgers in the UK increased their routes due to a hunting program. And some moose moved more through military maneuvers, while others were repeatedly exposed to skiers.

Agriculture and forestry, among other things, also played a role, according to Doherty and his team: For example, the sand lizard (Pedioplanis lineoocellata) in South Africa moved more frequently and over longer distances in overgrazed areas than in less disturbed locations. And the American black bear in our picture adapts its movements to the oil production.

“Our results indicate a global restructuring of animal movements and emphasize the need to reduce the negative impact of humans on movements,” the scientists sum up. “The consequences of changed animal movements can lead to reduced animal fitness, lower chances of survival, reduced reproduction rates, genetic isolation and even local extinction,” warns Doherty.

Recent Articles

Related Stories

Stay on op - Ge the daily news in your inbox