By Jocelyn N. Apodaca

A coyote approaches a baited camera on the White 
Sands National Monument. NMSU researchers placed
 cameras in more than 86 areas between 2011 and 2012
 to record data on predation behaviors between kit foxes 
and coyotes. Results of their research could be
 published in the journal Ecology. (Gary Roemer 
— photo courtesy of nmsu)

Take a stroll through the gypsum dunes of White Sands 
National Monument and you might come across paw prints
 belonging to a kit fox or coyote.

Kit Fox










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 also seen in sharks, spiders,
 hyenas and many other animals. In this case, the
 coyote is the predator of the kit fox.

Aware of this relationship, and concerned about the
 impact it could have on the kit foxes, the National 
Park Service sought the help of New Mexico State 
University professor Gary Roemer to implement a 
study on the animals' behavior.

Roemer, who teaches fish, wildlife and conservation
 ecology, 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.

Coyote








"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 at White Sands National Monument. "This was the first in-depth 
study to be conducted on mammals of the monument."

The research shows 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 ways to acquire water: free water
, preformed water (already in your food), 
and metabolic water (released when food
 is digested). The predators must get both
 their energy and water from 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 
groundwater 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."

"Eye on Research" is provided by New Mexico
 State University. This week's feature was
 written by Jocelyn Apodaca of University 
Communications. Follow NMSU News on
 Twitter:http://twitter.com/nmsunews.
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/www.facebook.com/NMSUNews
------------------------------------------------

Effects of Habitat on Competition Between Kit Foxes and Coyotes

  1. JULIA L. NELSON1,†,*,
  2. BRIAN L. CYPHER2,
  3. CURTIS D. BJURLIN3,‡ and
  4. SCOTT CREEL4
Article first published online: 13 DEC 2010
DOI: 10.2193/2006-234
Issue
The Journal of Wildlife Management

The Journal of Wildlife Management

Volume 71, Issue 5, pages 1467–1475, July 2007
Abstract: San Joaquin kit foxes (Vulpes macrotis mutica) are an endangered species with a narrow geographic range whose natural populations are limited by predation by coyotes (Canis latrans). In the warm, arid grassland and shrubland habitats where kit foxes occur, coyotes are more cover dependent than kit foxes, creating the possibility of habitat segregation.

 Effects of habitat variation on coyote and kit fox competition are unknown. We assessed exploitation and interference competition between coyotes and kit foxes in grassland and shrubland habitats to determine if such competition varies among habitats. With respect to exploitation competition, we evaluated habitat and spatial partitioning, diet, prey abundance, and survival for kit foxes and coyotes at the Lokern Natural Area in central California, USA, from January 2003 through June 2004.

 Kit foxes partitioned habitat, space, and diet with coyotes. Coyotes primarily used shrubland habitats whereas kit foxes selectively used burned grasslands. Kit foxes and coyotes had high dietary overlap with regards to items used, but proportional use of items differed between the 2 species. Kit foxes selected for Heermann's kangaroo rats (Dipodomys heermanni), which were closely tied to shrub habitats. With respect to interference competition, predation was the primary source of mortality for kit foxes, and survival of individual kit foxes was inversely related to proportion of shrub habitat within their home ranges. Our results suggest that a heterogeneous landscape may benefit kit foxes by providing habitat patches where predation risk may be lower.