As images of reindeer prance across our television screens and adorn our greeting cards this holiday season, real-life reindeer populations are on the decline around the world, largely due to human activity.

According to a new study in the Journal for Nature Conservation, one population in China has declined nearly 30 percent in the last four decades as poachers, predators, and tourists exacerbate threats from climate change and habitat loss.

Think about that this holiday season.

The study, led by Renmin University of China professor Xiuxiang Meng, looked at a small population of reindeer in Inner Mongolia that is herded by local Ewenki people in the village of Aoluguya. The villagers have relied on the animals for their meat, milk, and hides for more than 300 years. Reindeer populations in the area peaked at more than 1,080 individuals in 1982, the study found, then plummeted to 463 in the late 1990s. They're now hovering at around 770 spread across eight herds.

"The data show an impressive decline due to several factors but mainly mediated by human activities," Susana Gonzalez, chair of the International Union for the Conservation of Nature's (IUCN) deer specialist group, told VICE News.

Poachers looking for antlers are responsible for more than half of abnormal deaths, the study found. And herders often move their reindeer away from prime feeding grounds to be closer to active tourist areas, where reindeer are frequently hit by cars or choke on plastic bags. They may even be sold to tourists looking for an exotic pet.

Though these semi-domesticated reindeer face unique threats, they're not alone in their dwindling numbers. The first-ever comprehensive census of reindeer, published in 2009, found that at least 34 of the world's 43 major monitored herds had declining numbers, with an average population drop of 57 percent from their historic highs, largely due to climate change.

Earlier spring thaws mean plants sprout before the migrating herds arrive to eat them and warmer summers mean more insects, which harass the reindeer and prevent them from feeding. Freezing rain, instead of snow, can kill off lichens, which the reindeer feed on during colder parts of the year.

The decline of reindeer was forecast as early as the mid-1990s. In December 1996, the World Wide Fund reported that herds in Alaska were fragmenting as they were forced from their feeding grounds due to warmer temperatures. In Russia that year, 4,500 reindeer died from starvation linked to unusual weather events.

In 2012, unseasonally warm January temperatures in Norway increased reindeer deaths on the island of Svalbard to among the highest ever recorded — though warm summer temperatures may have created better foraging conditions and helped to offset the number of deaths.

The National Oceanic and Atmospheric Administration's 2013 Arctic Report Card found that declines since 1970 had varied among herds from 31 percent to 97 percent. The wide range in numbers may in part be due to natural 40- to 60-year population cycles.

"The semi-domesticated (reindeer) population in China, Mongolia, and Russia—and especially China—should be given enough concern by the IUCN Red List," Xiuxiang Meng of Renmin University told Discovery News. "Our survey showed that the reindeer in China comprise the southernmost reindeer population in the world, which is so important to the distribution and conservation of reindeer worldwide."

Gonzalez said it's important for conservation work to happen at the regional and national levels.

"The authors clearly highlight the importance of protecting the habitat by establishing natural reserves and national parks within the reindeer's range in China to conserve this fragile population," Gonzalez told VICE News. "This last recommendation is the real solution to conserve the biodiversity and to protect and respect the habitat of the species range."

Follow Laura Dattaro on Twitter: @ldattaro