URBANA, Ill. — Majestic African antelopes known as gemsbok have been roaming the U.S. southwest since their introduction in the 1960s and 1970s. Brought to New Mexico as game species for hunting, gemsbok quickly settled in, expanding more than 100 kilometers from their introduction point. University of Illinois Urbana-Champaign researchers say that’s due to their exceptional adaptations to arid conditions, which they predict will dramatically expand under climate change.
In a new study , the researchers reveal the potential extent of the exotic species’ spread by the year 2100, with suitable habitat spilling well beyond New Mexico into Texas, Arizona, Utah, California, and even as far north as southern Washington and Montana. Should gemsbok disperse and proliferate into all of these spaces, the impacts to cattle, native wildlife, and plant communities could be significant.
The team mapped where gemsbok could survive under future climate scenarios based on their current habitat preferences.
“We turned towards participant science to do this work. When people contribute photos to apps like iNaturalist, the occurrence records get scraped into something called the Global Biodiversity Information Facility. From that, we were able to use a statistical method called Maxent to find habitat associations for gemsbok,” said the study’s lead author, Nathan Alexander, who began the research as a doctoral student in the Department of Natural Resources and Environmental Sciences , part of the College of Agricultural, Consumer and Environmental Sciences at U. of I. He’s now a postdoctoral scholar at Southern Illinois University .
For every gemsbok occurrence, the researchers looked at factors like temperature seasonality and precipitation, vegetation cover, terrain ruggedness, and human population density to paint a picture of where the animals spend time. Then they looked for similar habitat patterns across space and time to predict where gemsbok might go in the future. They found that many suitable habitats that now exist as isolated pockets will likely coalesce into larger, more contiguous habitats under future climate scenarios.
“When there are these isolated patches, there might be dispersal barriers that they can't cross to get to the next patch. But when these patches coalesce and connect, there might be increased opportunities for gemsbok to invade and expand into these novel habitats. We see this particularly in western Texas, but also into western New Mexico and up into Arizona, and even some regions of California, like Death Valley,” said Kieran Andreoni, who began the research as a master’s student in NRES. He’s now conservation director at the Southern Plains Land Trust in Colorado.
Native to the Kalahari Desert in southern Africa, gemsbok are particularly well suited for arid conditions and may have an advantage over southwestern native species under climate change.
“Gemsbok are famous for being really well adapted to heat and drought. In addition to other heat adaptations, they can get all of their water from plants, so they don't really need to drink. That’s really unusual for animals that big — they can weigh 450 pounds. They're the poster species for dealing with the kind of changes we're going to see in the southwest,” said study co-author Bob Schooley , professor and head of NRES.
Schooley adds that gemsbok left their natural predators — lions and hyenas — back in Africa, and southwestern predators like coyotes and mountain lions don’t kill nearly as many gemsbok. Considering their superior adaptation to arid climates and relative freedom from predators, the spread of gemsbok could threaten both domestic and native species.
The primary concern is diet overlap — with larger gemsbok herds eating the same forage as cattle and natives like pronghorn and bison, gemsbok could diminish food reserves for those species.
“Along with that diet overlap, gemsbok are able to forage on lower quality plant materials than some of our native species,” Alexander said. “So in drought years, we could imagine our native species might be a little bit more stressed and nutrient deficient, whereas the gemsbok are going to be able to move to less nutrient-rich plant material and still be able to persist in the environment.”
Schooley added, “These desert rangelands are often used for cattle grazing. When there’s a severe drought, they pull the cattle off the landscape because there's no food for them. Well, no one pulls the gemsbok off. Considering their ability to survive on low-quality forage, they could severely damage remaining grasslands. So I think that's the kind of thing we worry about — what are the implications when they get to even larger numbers?”
Alexander says there is also potential for gemsbok to carry and spread diseases to native and domestic ungulates. Gemsbok in the southwest have tested positive for malignant catarrhal fever, bovine respiratory syncytial virus, and bovine para-influenza-3, which are of concern to the cattle industry.
With competing interests between conservationists, ranchers, and hunting operations, the researchers say it will be tricky but critical to manage the population into the future to avoid potential consequences across the southwest.
The study, “Predicted range expansion of exotic Gemsbok (Oryx gazella) under climate change in the United States,” is published in the Journal of Mammalogy [DOI: 10.1093/jmammal/gyag083 ].
Research in the College of ACES is made possible in part by Hatch funding from USDA’s National Institute of Food and Agriculture. This study was also supported by a competitive NIFA grant (no. 7006200) and the National Science Foundation ( Jornada Basin Long Term Ecological Research Program , DEB 2025166 and DEB 2425143).
Alexander and Schooley are also affiliated with the Illinois Natural History Survey , part of the Prairie Research Institute at U. of I.
Journal of Mammalogy