Human disturbances are globally restructuring animal movement

A global analysis of how human disturbances impact animal movement has revealed widespread impacts that threaten the survival of many species. The experts report that human activities force animals to move an average of 70 percent further to survive. 

“Movement is critical to animal survival, but it can be disrupted by human disturbances,” said study lead author Dr. Tim Doherty, a wildlife ecologist at the University of Sydney. “Animals adopt behavioral mechanisms to adjust to human activity, such as by fleeing or avoiding humans, traveling further to find food or mates; or finding new shelter to avoid humans or predators.”

It is well documented that long-term disturbances, such as logging and urbanization, have major impacts on wildlife. But the new study shows that periodic events like hunting, recreation, and military activity can trigger even bigger changes in animal behavior.

The researchers analyzed 208 separate studies on 167 animal species over four decades to investigate how human disturbances influence animal movement. In more than one-third of cases, animals were forced into changes that saw movement increase by more than 50 percent.

The species examined in the analysis range from the tiny sleepy orange butterfly to the massive great white shark. 

The study revealed that changes in animal movement in response to human disturbances are common. Episodic disturbances like hunting were found to have the strongest effect, and ncreases in animal movement averaged 70 percent.

In some cases, human activity forced a reduction in animal movement, and these decreases averaged 37 percent.

According to the study, animals moved less when they encountered increased access to food in human locations, the reduced ability to move from a modified habitat, or restrictions to their movement by physical barriers.

“As well as the direct impact on animal species, there are knock-on effects,” said Dr. Doherty. “Animal movement is linked to important ecological processes such as pollination, seed dispersal and soil turnover, so disrupted animal movement can have negative impacts throughout ecosystems.”

“In marine environments and landscapes relatively untouched by human impact, it is important that habitat modification is avoided. This could involve strengthening and supporting existing protected areas and securing more areas of wilderness for legal protection.”

“It is vital we understand the scale of impact that humans have on other animal species. The consequences of changed animal movement can be profound and lead to reduced animal fitness, lower chances of survival, reduced reproductive rates, genetic isolation and even local extinction.”

The study is published in journal Nature Ecology and Evolution.

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By Chrissy Sexton, Earth.com Staff Writer