For the first time, scientists have calculated the global impact of human activity on animal movement, revealing widespread impacts that threaten species survival and biodiversity. Episodic human activity – like hunting, oil pipeline construction, military maneuvers and recreation – have the biggest impact. Increases in animal movement averaged 70 percent. The study points to a global restructuring of animal movements caused by human disturbance, with potentially profound impacts on animal populations, species and ecosystem processes.
“”Movement is critical to animal survival, but it can be disrupted by human disturbances. 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…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.”
-Dr. Tim Doherty, wildlife ecologist, University of Sydney
The research compiled and analyzed 208 separate studies on 167 animal species over 39 years to assess how human disturbance influences animal movement. In more than one-third of cases, animals were forced into changes that saw movement increase by more than 50 percent.
Species covered in the study range from the 0.05 gram sleepy orange butterfly to the more than 2000 kilogram great white shark. There were 37 bird species, 77 mammal species, 17 reptile species, 11 amphibian species, 13 fish species and 12 arthropod (insect) species covered.
Study Findings Overview
– Changes in animal movement in response to disturbance are common
– Episodic human activities such as hunting, aircraft use, military activity and recreation can cause much greater increases in movement distances than habitat modification such as logging or agriculture
– Episodic disturbances force a 35 percent overall change in movement (increase and decrease); habitat modifications force a 12 percent change
– Decreases in animal movement averaged 37 percent…In some cases, human activity forced a reduction in animal movement because of increased access to food in human locations, reduced ability to move from modified habitat or restrictions to movement by physical barriers.
– Increases in animal movement averaged 70 percent
The study findings have far reaching implications for public policies and managing animal biodiversity. Reducing negative impacts of human activity on animal movement will be vital for securing biodiversity in an increasingly human-dominated world. This could involve strengthening and supporting existing protected areas and securing more areas of wilderness for legal protection. The study findings suggest it might be easier to reduce the impacts of episodic disturbances by carefully managing certain activities, such as hunting and tourism, in wilderness areas, especially during animal breeding periods.
Journal Reference: Doherty, T.S., Hays, G.C. & Driscoll, D.A. Human disturbance causes widespread disruption of animal movement. Nature, Ecology and Evolution, 2021. DOI: 10.1038/s41559-020-01380-1