Take a stroll through the unique gypsum dunes of White Sands National Monument and you might come across paw prints belonging to a kit fox or coyote.
These two predators coexist in an extreme form of competition called intraguild predation. When two predators compete for the same prey, the larger often kills and may even consume the smaller predator. This is a phenomenon familiar with sharks, spiders, hyenas and many other animals. In this case, the coyote is the predator of the kit fox.
Aware of this relationship and concern for the impact it could have on the kit foxes, the National Park Service sought the help of New Mexico State University Fish, Wildlife and Conservation Ecology Professor Gary Roemer to implement a study on the animals’ behavior.
Roemer, former NMSU graduate student Quinn Robinson and a team of researchers set up cameras in six different habitats on the monument to estimate the probability of an animal being in a particular area.
“The gypsum sand dunes is a unique ecosystem in New Mexico, but at the same time there are similar environments found throughout North America and the world,” Roemer said. “Our results were applicable to other sand dune environments. It’s very unique but at the same time it’s general.”
After scanning photos and interpreting two years’ worth of data, the NMSU researchers released their findings to the Ecological Society of America, where it is pending publication in the journal Ecology.
“Before this study we knew very little about mammals of the monument or the distribution of mesocarnivores within the park,” said David Bustos, resource program manager White Sands National Monument. “This was the first in-depth study to be conducted on mammals of the monument.”
Research states that kit foxes are found throughout the park, whereas coyotes are restricted to shrub lands where prey is most abundant. In the dunes the kit foxes appear to be more abundant where coyotes spend little to no time.
“The distribution of prey influences the distribution of coyotes,” Roemer said. “But it seems that where the kit foxes live away from coyotes there’s a larger abundance of kit foxes.”
The kit foxes possess adaptations that enable them to live in more arid areas, where a coyote is less likely to survive.
“Kit foxes have very efficient kidneys, large ears to dissipate heat and they dig dens to escape the heat of the day, which reduces the amount of water they need,” Roemer said. “Sometimes while foraging for rodents and rabbits, they are really hunting for water as opposed to energy.”
Because there is no permanent water source on the park, both species have to get their water from their food. There are three types of ways to acquire water: free water, preformed water (already in your food), and metabolic water (released when food is digested). They must get both their energy and water from only the food they consume.
“The other thing that makes it interesting is that there is some discussion about using desalinization techniques in and around the sands for water, because we are so water stressed,” Roemer said. “There’s some potential that pumping out that ground water could destabilize the dunes.”
Geographically speaking, the gypsum sand dunes are a new feature on Earth and have only been around for the last 30,000 years, or so.
“The more we find out about the ecology of the dunes and what an interesting place it is, from a natural perspective, I would hope folks would choose to preserve it rather than negatively impact it,” Roemer said. “If you have ever walked the dunes on a summer morning or under a moonlit night, you know what a special and evocative place it is. It’s one of the natural wonders of our region.”
“The monument has greatly benefitted from the NMSU Fish and Wildlife Department,” Bustos said. “It is great to have so many experts close by and the students have always been great to work with. They’re so hard-working and inquisitive.”
Information from NMSU