Wild bison have been reintroduced to a national park in southwestern Canada for the first time in a century after being airlifted from another national park, according to the Canadian Press Monday. The majority of the 16 bison brought to the Banff National Park Wednesday were pregnant two-year-olds in the hopes of strengthening the species' population.

The bison traveled roughly 275 miles in custom-made shipping containers trucks through Alberta, from Elk Island National Park, which is about 20 miles east of Edmonton, to Banff, which is about 80 miles west of Calgary. After arriving at a location just outside of the Banff, the shipping containers were lifted by a helicopter and flown to an enclosed pasture inside the park, where the bison were released, according to British Columbia-based Global News Monday. 

The bison will be monitored in that pasture for 16 months by park rangers using radio collars in the first phase of their five-year plan to reintroduce the species into the park. Park rangers hope that by the summer of 2018, they will able to relocate the bison into a 1,200 square-kilometer area on the eastern slopes of the park so the beasts can integrate into their new habitat by interacting with other native species and finding their own food.

While conservation activists, including Environment Minister Catherine McKenna, have praised the $6.4-million project, ranchers living on the eastern slopes of the park have reportedly criticized the plan, citing the bison could escape, damage property or spread diseases to livestock.

But advocates for the relocation say they addressed the concerns by carefully selecting and vetting the 16 bison brought to the park. Before they were moved from Elk Island National Park, the bison were quarantined for three weeks for health testing until they were deemed disease free.

McKenna said the relocation was not just important because of its ecological significance but that it also had a "great spiritual meaning" for the indigenous people of Canada. She highlighted that reintroducing the bison would help celebrate the 150th anniversary of Canada’s Confederation.

"By returning plains bison to Banff National Park, Parks Canada is taking an important step towards restoring the full diversity of species and natural processes to the park's ecosystems while providing new opportunities for Canadians and visitors to connect with the story of this iconic species,” McKenna said in a statement.

Thousands of bison herds had previously roamed the U.S. prairies to the northern area that is now the Banff National Park until hunting endeavors decimated the population.