A captured dark kangaroo mouse is attached to a scale as part of the small mammal data collection process at Hill Air Force Base, Utah. Photo courtesy Jessica Swift. BY TIM SCHOMMER
It’s nighttime on military training land in the arid desert west of Utah’s Great Salt Lake. A small, roundish mammal with long hind legs hops through the darkness, foraging for seeds in the sandy soil. It’s a dark kangaroo mouse, a state-protected species discovered in 2015 on Hill Air Force Base’s Utah Test and Training Range (UTTR), one of the largest restricted airspaces in the contiguous United States. Hill AFB itself is east of the Great Salt Lake, while the Utah Test and Training Range lies to the west. The UTTR covers more than 2,700 square miles of land; it has a North range and a South range, divided by a highway.
To learn more about the populations, habitat, and behavior of sensitive species on the UTTR, including this nocturnal rodent, the Hill AFB Natural Resources Program is partnering with CSU’s CEMML. The effort helps the military plan operations while avoiding harm to sensitive species; it also helps restore training land to health. Christi Gabriel, a principal investigator with CEMML, said, “The Great Salt Lake Desert has been invaded by cheatgrass and one of the Natural Resources Program’s goals is to help restore native shrubs and grassland to the UTTR. So, monitoring species like the dark kangaroo mouse can provide an indication of how the vegetation on the range is performing.”
Gathering Data
Historically, the dark kangaroo mouse has been found in four counties within the state of Utah. However, recent studies suggest their range is shrinking. Today, one of the largest and best documented populations of the species falls within Tooele County, specifically in and around the UTTR’s South range. The dark kangaroo mouse also exists in other Great Basin states, including California, Idaho, Nevada, and Oregon.
Species monitoring efforts on the UTTR have been conducted since the late 90s to get a better picture of species diversity and numbers. Over the years, the list of species monitored has expanded to include burrowing owl, pinyon jay, American bumble bee, kit fox, Townsend’s big-eared bat, and golden eagle.
Using Data to Find Habitat
Ongoing survey work provides more information on the behaviors and preferences of all species being studied. For example, initially, the dark kangaroo mouse was thought to be restricted to sand-dune habitat on the range, but further analysis showed that potential habitat also included less-sandy soils than the species was historically found in.
“By taking the survey data from the last several decades,” said Jessica Swift, a CEMML natural resources specialist at Hill AFB, “I was able to create a habitat suitability model for dark kangaroo mouse that took locations where they had been captured, compiled them in GIS, and spit out a probability of where habitat might exist for the species.”
Information collected from surveys and GIS analysis is utilized when the Air Force is planning exercises for training or weapons testing on the installation. The natural resources program consults with project proponents to determine potential impacts, recommend ways to minimize or avoid conflicts, and mitigate impacts to rare species or habitats.
The Hill AFB Natural Resources Program also uses survey data and GIS analysis results to guide conservation actions, help with resilience planning, and inform policy change. The Program has shared results with other agencies (e.g., state/federal governments, local universities, non-profit organizations) for collaboration for improved research efforts and knowledge.
Prioritizing Ecosystem Restoration
The survey work is fueled in large part by the 1960 Sikes Act, which requires the military to coordinate with federal and state wildlife agencies to conserve wildlife and habitat while enabling training and operations to continue. The same is true for the National Historic Preservation Act of 1966, which similarly balances the need for military operations with the preservation of historic and cultural properties. Depending on what the wildlife surveys find, the natural resources management team may recommend that military operations be moved to a different area on base, or conducted at a different time of year so as not to interfere with mating season or other important wildlife behaviors.
Conducting surveys, analyzing data, and informing management decisions also plays a crucial role in how the Air Force spends its limited natural resources management budget. By understanding the bigger picture of the installation’s ecosystems, the natural resources management team can target resources toward areas where species diversity and habitat quality are lower and restoration is needed.
Keeping a close eye on ecosystem health is beneficial for both military operations and the plants and animals that call the installation home. By carefully managing species of concern, the natural resources team aims to help keep them off the federal Threatened and Endangered Species list.
If a species such as the dark kangaroo mouse were to be listed under the Endangered Species Act, required protections could change how military operations on an installation can be conducted.
Species Monitoring is Interrelated
While no species at Hill AFB and the UTTR currently fall under the protection of the Endangered Species Act, several of them are considered mission-critical or at risk. The list of species being monitored has grown over the years, as the wellbeing of one species can provide valuable information about the health of others.
While small mammal monitoring began in the late 90s, by 2006 the team had added golden eagle monitoring as well, a species protected under the Bald and Golden Eagle Protection Act. From there, monitoring efforts expanded to include more habitat and a wider range of species, with an eye toward discovering more about the eagle’s prey base. Those additional efforts for the golden eagle eventually led to the discovery of the kangaroo mouse on UTTR.
As with all ecosystems, the health of one species is inextricably entwined with the health of other species. “The golden eagle became this umbrella species,” said Gabriel. “Protecting the more than 18 nesting pairs present at Hill AFB helps protect all these other species, including the dark kangaroo mouse.”