New Paper Published: Relationships Between Climatic Variation and Population Dynamics of the Threat
July 28, 2026
Sharon Poessel
Ecology and Evolution, 2026; 16:e73952
Abstract
Climate change has elevated the intensity and frequency of droughts, affecting wildlife population dynamics. In arid environments, drought can have severe consequences for life history parameters, such as survival and emigration, especially for species of conservation concern. We analyzed a 34-year
dataset in a mark-recapture framework to estimate demographic parameters for Mohave ground squirrels (Xerospermophilus mohavensis), a threatened species confronted with climate change and drought. Specifically, we examined the influence of individual-, geographic-, and environmental-related variables on survival, emigration, emigration fidelity (i.e., the probability that an animal that has moved away from the study site will remain away), capture probability, recapture probability, and number of unmarked animals, the latter of which allowed us to estimate population size. We captured 1404 squirrels at four study sites. Overall, male squirrels had lower survival and higher emigration rates than did female squirrels, and juveniles had lower survival than adults. Emigration was lower at the highest-elevation study site than at other sites. Survival of male squirrels increased with higher levels of vegetation greenness. At two of the four study sites, emigration
of squirrels of both sexes decreased with higher levels of vegetation greenness. No variables influenced emigration fidelity or number of unmarked animals. Initial capture probabilities were lower for males than for females, and for juveniles than for adults, whereas recapture probabilities were lower for adults than for juveniles. Population size fluctuated over time with several peaks during the study separated by periods of low numbers, which occasionally fell to zero at each site. By the end of the study, adult population size at the two sites with the longest-term monitoring was 70% lower than its peak early in the study. Demography of Mohave ground squirrels was characterized by a large amount of variation, leaving them highly vulnerable to additional stress from climate change. Our findings suggest that conservation management actions, such as prioritizing sites with consistently high levels of vegetation greenness, protecting contiguous areas of suitable habitat, and enhancing emigration success of squirrels, may promote the long-term viability of this species as climate changes. They also illustrate how long-term population monitoring can be used to support management for other conservation-relevant
species affected by climate change and drought.
Read/Download the entire paper . . .
2026 Phil Leitner award recipient - Scott Osborn
February 4, 2026
Congratulations and thank you to Scott Osborn, the 2026 recipient of the Phil Leitner award.
In appreciation for all of his contributions to the survival and well-being of the Mohave ground squirrel, Scott Osborn has been awarded the MGSCC's Phil Leitner award. The MGSCC and Mohave ground squirrel thank Scott for all of his efforts and the support he has provided throughout the years!
Here are some highlights of Scott's contributions to the Mohave Ground Squirrel:
As CDFW’s Statewide Coordinator for Small Mammal Conservation from 2009 to his retirement in 2023, Scott worked with many researchers, consultants, and other agency biologists on issues related to listed and special status rodents, insectivores, lagomorphs, and bats.
Specific achievements related to the Mohave Ground Squirrel:
- Coordinated the MGS Technical Advisory Group (2009-2023); facilitated biannual MGS TAG meetings, coordinated CDFW input on TAG agenda topics, and developed the CDFW MGS and MGS TAG webpages, which include informational resources for TAG members and other interested parties.
- Served as final lead author and editor of CDFW’s Conservation Strategy (2019). This document, which included many contributors over a period of more than 10 years, serves as compendium of scientific information on MGS available at the time of publication and will be foundational to recovery planning for MGS.
- Worked as a bridge between MGS MOU holders and the Wildlife Branch’s research permit group to facilitate permitting.
- Developed the first substantial update to CDFW’s MGS Survey Guidelines (2023), which now includes provisions for the use of camera traps to detect MGS.
- Helped develop financial support for a variety of projects for MGS researchers and the MGS Conservation Council.
- Presented at the TWS MGS workshops (2022).
- Participated in the US ACOE-funding MGS Symposium (2012).
Comments submitted: Kramer Junction Travel Stop project
September 22, 2025
Kramer Junction Travel Stop - Initial Study Mitigated Negative Declaration APN: 0491-151-11 San Bernardino County
August 2025
The County of San Bernardino is reviewing an application submitted by Steeno Design Studio Inc. to construct and operate a travel stop. There would be a total of four (4) parcels included in the proposed development. The total area of the land is 35.97 acres; however, the area of the proposed development will be approximately 4.69 net acres located on the southwest corner of the parcel. The remaining area of the parcel will be approximately 18.53 acres and reserved for future development. A Tentative Parcel Map (TPM) has been submitted to subdivide the 35.97-acre parcel into 4 parcels and a remainder lot. The land to be developed would be subdivided into 4 parcels (referred to as Parcels 1 through 4.
The comment document can be downloaded below . . .
Comments submitted: Persistence Mine Reclamation Plan Notice of Availability and Notice of Intent
August 18, 2025
Persistence Mine Reclamation Plan Notice of Availability (NOA) and Notice of Intent (NOI) to Adopt an Initial Study/Mitigated Negative Declaration
The project proposes to extract gold from semi to unconsolidated gravels, sands, and silts (sediments located within placer mining claims managed by the BLM. The sediments have been extensively tested and show economic gold grades suitable for surface mining extraction down to a tested depth of 24 feet, covering approximately 106 acres on 267 acres, across two non-contiguous pits. These two pits are referred to as the western and eastern pits. The proposed operation capacity is to process up to 96,000 cubic yards of material per month.
San Bernardino county has issued the Notice of Availability (NOA) and Notice of Intent (NOI) stating that the project's environmental review meets the State requirements of the California Environmental Quality Act.
The MGSCC provided more current data regarding Mohave ground squirrel observations near the proposed project site.
The comment document can be downloaded below . . .
URGENT - DATA REQUESTED. Mohave Ground Squirrel 5-Year Species Review
May 8, 2025
CA Department of Fish and Wildlife
In August of 2023, the California Department of Fish and Wildlife initiated a five-year species review for the state threatened Mohave ground squirrel (Xerospermophilus mohavensis) to inform the California Fish and Game Commission's decision on whether to retain or change the status of the species under the California Endangered Species Act (CESA). As part of this process, the department is seeking information or data on Mohave ground squirrel. To submit information or data, or to provide questions or comments about the review process, please email the Wildlife Diversity Program and include “Mohave ground squirrel” in the subject line.
Read the entire bulletin . . .
Petition submitted to list the Mohave Ground Squirrel on the Endangered Species List
December 13, 2023
Endangered Species List
On December 13, 2023, the Defenders of Wildlife, the Desert Tortoise Preserve Committee and the Mohave Ground Squirrel Conservation Council filed a petition with the Department of the Interior to list the Mohave ground squirrel (Xerospermophilus mohavensis) as a threatened species and to designate critical habitat concurrent with the listing.
“Recent presence/absence trapping summaries by Dr. Phil Leitner have shown that the Mohave ground squirrel’s range is shrinking in all directions except from the northwest, and that hybridization with the common round-tailed ground squirrel is threatening the species from the east as far west as Harper Lake Road. This new information since the previous two petitions provides evidence that federal listing is warranted,” said Ed LaRue, board member of the Mohave Ground Squirrel Conservation Council. “With federal protections under the Endangered Species Act, proactive conservation of the species on our large military bases within the range – particularly Edwards Air Force Base, Fort Irwin and China Lake Naval Air Weapons Station – is necessary to avoid extinction.”
Copies of the petition documents can be downloaded using the links below . . .
MGS Species Distribution
Distribution
The Mohave ground squirrel (Xerospermophilus mohavensis) is a species of ground squirrel found only in the Mojave Desert in California. This squirrel inhabits the western Mojave Desert in portions of Inyo, Kern, Los Angeles, and San Bernardino counties. It can occupy Joshua tree woodlands, creosote scrub, saltbush scrub and mojave mixed woody scrub. Typical forage plants are those that meet nutritional and water content requirements. These can include shrubs such as winterfat, spiny hopsage, and boxthorn (Lycium spp.).
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