In 2010, the Himalayan nation of Nepal was one of 13 countries to commit to doubling its wild tiger populations by 2022. In the decade since, Nepal is the only country to have achieved that goal. Over that time, other iconic species, including rhinos and elephants, have also seen an increase. What's behind the success? And what does it mean for the communities living with the tigers? The BBC's Asia editor Rebecca Henschke reports from Bardiya national park