Research

The New Mexico jumping mouse occurs in several areas of the Southwest and is listed as endangered under the Endangered Species Act. My research helped establish that it requires tall dense herbaceous riparian vegetation on saturated soil and can be lost due to excessive livestock grazing and other threats.  This information provides the basis for most of the management for the species.

 Frey, J.K., and J.L. Malaney.  2009.  Decline of the meadow jumping mouse (Zapus hudsonius luteus) in two mountain ranges in New Mexico.  The Southwestern Naturalist, 54:31-44. article link 

Frey, J.K. 2017. Landscape Scale and Microhabitat of the Endangered New Mexico Meadow Jumping Mouse in the White Mountains, Arizona.  Journal of Fish and Wildlife Management, 8:39-58. article link 

Nectar feeding bats migrate from the southwestern US to central Mexico and are threatened by habitat loss, cave disturbance, and other factors.  We modeled the distribution of these bats based on food resources (e.g., flowering agave and columnar cacti) and other variables.  We then used circuit theory (a process originally developed to understand the flow of electrical energy) to predict the migratory pathways of the bats. Our research confirmed that these bats follow a "nectar corridor" during migration along the western Pacific slope of Mexico.  These results help identify critical habitat that must be maintained to support these important bat populations.

 Burke, R., J.K. Frey, A.C. Ganguli, K.E. Stoner.  2019.  Species distribution modeling supports "nectar corridor" hypothesis for migratory nectarivorous bats and conservation of tropical dry forests.  Diversity and Distributions, 25: 1399-1415. link to article 

Burke, R., J.K. Frey, and K. E. Stoner. 2021. Using species distribution modeling to delineate richness patterns of chiropterophyllic plants and allocate conservation efforts in Mexico and the southwestern United States.  Natural Area Journal, 41:85-92. https://doi.org/10.3375/043.041.0203 link to article 

The American ermine occurring in New Mexico is the smallest carnivore in the world.  It is so small that it is not harvested or often studied leading to paucity of information about its  biology and conservation status.  We compiled information on the species in New Mexico and used machine learning methods to predict its habitat.  We found that this tiny weasel requires both healthy riparian vegetation found near beaver ponds and adequate winter snow cover, both of which are at risk due to climate change.

Frey, J.K., and M. Calkins. 2014.  Snow cover and riparian habitat determine the distribution of the short-tailed weasel (Mustela erminea) at its southern range limits in arid western North America.  Mammalia, 78:45-56. article link 

We used remote camera surveys and occupancy models to evaluate the extent and causes of extirpation of the Organ Mountains Colorado chipmunk.  We fund that the chipmunk has been extirpated from > 60% of historical sites with extensive retraction of its distribution higher in elevation.  We concluded that the extirpations were due to niche reduction as a result of climate change rather than habitat loss per se.  Our spatial models allowed us to identify remaining core habitat for the chipmunk so that safeguards can be enacted to protect the habitat and the chipmunk.

Jacobson H.N., and J.K. Frey.  In preparation. Niche reduction drives extirpation and habitat selection.

We predicted historical, current, and future distribution of the Dusky Grouse in in the Southwest.  We found that recent wildfires caused a substantial loss of their coniferous forest habitat, and that future climate change is likely to eliminate most habitat in most areas.

Youtz, J., R. Goljani Amirkhiz, and J. K. Frey. 2022. Modeling the impact of climate change and wildfire on the Dusky Grouse (Dendragapus obscurus) in the American Southwest: implications for conservation. Avian Conservation and Ecology 17(1):35. https://doi.org/10.5751/ACE-02222-170135 article link 

Mountaintops may serve as "sky islands" for many mammals because montane environments are often surrounded by "seas" of desert or grassland.  Island biogeographic theory indicates that species on an island are at equilibrium between contrasting forces of colonization and extinction, which are dictated by island isolation and area, respectively.  In contrast to this theory, montane mammal communities occurring on sky islands in the Southwest are structured only by extinction related to the timing of isolation of the mountaintop habitat.

Frey, J.K., T.L. Yates, and M.A. Bogan.  2007.  Mountaintop island age determines species richness of boreal mammals in the American Southwest.  Ecography, 30:231-240. article link 

We used spatial models using machine learning methods to predict places where Mexican wolves kill cattle.  When the model is projected across the Southwest, it shows that some areas have higher risk of depredations than others.  This information can help inform management by allocating more resources to risky areas.

Goljani, R., J.K. Frey, J. W. Cain III, S. W. Breck, D. L. Bergman.  2018.  Predicting spatial factors associated with cattle depredations by the Mexican wolf (Canis lupus baileyi) with recommendations for depredation risk modeling.  Biological Conservation, 224:327-335. article link 

We used remote cameras to monitor the daily activity pattern of the Organ Mountains Colorado chipmunk across the year.  We used the data to understand how activity pattern varied in response to climate and then predicted the chipmunk's activity in future climates.  We found that in future years the chipmunk is likely to face immense threats due to shifts when it can be active as a result of climate change.

Schweiger, B.R. and J.K. Frey.  2021.  Weather determines daily activity pattern of an endemic chipmunk with predictions for climate change.  Climate Change Ecology, 2:100037  article link 

The Peñasco least chipmunk has been proposed for listing on the Endangered Species Act as endangered. The current known populations are estimated to have < 50 individuals making any invasive survey methods risky.  We use remote cameras to study the chipmunk, but that is complicated because another similar looking and common chipmunk (gray-footed chipmunk) co-occurs with the Peñasco chipmunk.  To alleviate potential problems of misidentification that could cause bias in our results, we developed rigorous methods for identifying the chipmunks and evaluated the best statistical methods for treating the data.  This gives assurance that our results are robust and can be used to inform management to recover the chipmunk.

McKibben, F.E., and J.K. Frey.  2021. Linking camera-trap data to taxonomy: Identifying photographs of morphologically similar chipmunks.  Ecology and Evolution, 11: 9741-9764.  article link

 McKibben, F.A., F. A. Gebresselassie, J.K. Frey.  2023.  To model or not to model: False positive detection error in camera-trap surveys.  Journal of Wildlife Management, 87(3): e22365  article link