For the first time, scientists have calculated the global impact of humanactivity on animal movement, revealing widespread impacts that threatenspecies survival and biodiversity.
While it has been shown that activities such as logging and urbanisation canhave big impacts on wildlife, the study by scientists at the University ofSydney and Deakin University in Australia shows that episodic events such ashunting, military activity and recreation can trigger even bigger changes inanimal behaviour.
“It is vital we understand the scale of impact that humans have on otheranimal species,” said lead author Dr Tim Doherty, a wildlife ecologist at theUniversity of Sydney. “The consequences of changed animal movement can beprofound and lead to reduced animal fitness, lower chances of survival,reduced reproductive rates, genetic isolation and even local extinction.”
The study is published today in Nature Ecology & Evolution.
Key findings include:
- 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
- Increases in animal movement averaged 70 percent
- Decreases in animal movement averaged 37 percent
The study points to a global restructuring of animal movements caused by humandisturbance, with potentially profound impacts on animal populations, speciesand ecosystem processes.
“Movement is critical to animal survival, but it can be disrupted by humandisturbances,” Dr Doherty said. “Animals adopt behavioural mechanisms toadjust to human activity, such as by fleeing or avoiding humans, travellingfurther to find food or mates; or finding new shelter to avoid humans orpredators.”
In some cases, human activity forced a reduction in animal movement, the studyfound, because of increased access to food in human locations, reduced abilityto move from modified habitat or restrictions to movement by physicalbarriers.
“As well as the direct impact on animal species, there are knock-on effects,”Dr Doherty said. “Animal movement is linked to important ecological processessuch as pollination, seed dispersal and soil turnover, so disrupted animalmovement can have negative impacts throughout ecosystems.”
POLICY IMPLICATIONS
Dr Doherty, who started this research at Deakin University before moving tothe University of Sydney, has said the findings have important policyimplications for managing animal biodiversity.
“In marine environments and landscapes relatively untouched by human impact,it is important that habitat modification is avoided,” said Dr Doherty fromthe School of Life and Environmental Sciences in the Faculty of Science.
“This could involve strengthening and supporting existing protected areas andsecuring more areas of wilderness for legal protection.”
The study says it might be easier to reduce the impacts of episodicdisturbances by carefully managing certain activities, such as hunting andtourism, in wilderness areas, especially during animal breeding periods.
“Where habitat modification is unavoidable, we recommend that knowledge ofanimal movement behaviour informs landscape design and management to ensureanimal movement is secured,” Dr Doherty said.
He said that reducing negative impacts of human activity on animal movementwill be vital for securing biodiversity in an increasingly human-dominatedworld.
“Further research is needed to better understand the impact of habitatmodification on animal movement in rapidly developing parts of the world,” DrDoherty said.
The research compiled and analysed 208 separate studies on 167 animal speciesover 39 years to assess how human disturbance influences animal movement. Inmore than one-third of cases, animals were forced into changes that sawmovement increase by more than 50 percent.
Species covered in the study range from the 0.05 gram sleepy orange butterflyto the more than 2000 kilogram great white shark. There were 37 bird species,77 mammal species, 17 reptile species, 11 amphibian species, 13 fish speciesand 12 arthropod (insect) species covered.
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