Cheryl Brehme
Cheryl has been a biologist with the USGS, Western Ecological Research Center since 2003.
She specializes in long-term monitoring programs, conservation ecology and road ecology. She uses current ecological concepts and principles to design, implement, improve, and interpret complex research and monitoring projects for reptiles, amphibians and mammals. In addition to conducting fieldwork for her projects, she models a variety of spatial and demographic population processes and community dynamics in response to habitat change.
Long-Term monitoring
Cheryl has been integral in the design, fieldwork and dynamic occupancy analysis of data for long-term monitoring of endangered species on MCB Camp Pendleton to inform species status and trends and effective habitat and species management actions. These include the arroyo toad (since 2003), Stephens kangaroo rat (since 2005) and Pacific pocket mouse (since 2011).
Road Ecology
Cheryl leads a wide array of research on road ecology, particularly with respect to reptiles and amphibians for the Department of Transportation and other partners. Projects range from assessing risk of road impacts across multiple species, testing the effectiveness of individual components of crossing systems, designing new passages, to conducting wide scale landscape connectivity projects.
American Badger Research
Since 2011, Cheryl has led research studying badger distribution and activity in San Diego County using canine scent detection, badger sign surveys, infrared cameras, facial recognition, hair snags, outreach efforts, and road mortality to document their distribution and core use areas. Future goals include distribution mapping, designing a long-term monitoring program, and employing the use of radiotelemetry to better understand their space use patterns and conservation needs.
Science and Products
Research to inform Caltrans best management practices for reptile and amphibian road crossings
The influence of species life history and distribution characteristics on species responses to habitat fragmentation in an urban landscape
Track tube construction and field protocol for small mammal surveys with emphasis on the endangered Pacific pocket mouse (Perognathus longimembris pacificus)
Quantifying climate sensitivity and climate-driven change in North American amphibian communities
Effects of urbanization, and habitat composition on site occupancy of two snake species using regional monitoring data from southern California
An objective road risk assessment method for multiple species: ranking 166 reptiles and amphibians in California
Longevity and population age structure of the arroyo southwestern toad (Anaxyrus californicus) with drought implications
An improved camera trap for amphibians, reptiles, small mammals, and large invertebrates
Metabarcoding of fecal samples to determine herbivore diets: A case study of the endangered Pacific pocket mouse
Permeability of roads to movement of scrubland lizards and small mammals
Joint estimation of habitat dynamics and species interactions: Disturbance reduces co-occurrence of non-native predators with an endangered toad
Effects of large-scale wildfire on ground foraging ants (Hymenoptera: Formicidae) in southern California
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Filter Total Items: 29
Research to inform Caltrans best management practices for reptile and amphibian road crossings
In October of 2014, the U.S. Geological Survey (USGS) began a 5-year project to conduct research to inform Best Management Practices (BMPs) for amphibian and reptile crossing and barrier systems in California. To inform future conservation and transportation planning, this project involved identification of species at highest risk of negative road impacts, creation of geodatabase and spatial mappAuthorsCheryl S. Brehme, Robert N. Fisher, Tom E. S. Langton, Anthony P. Clevenger, Esther Adelsheim, Stephanie Barnes, Tristan Edgarian, Brittany Ewing, Stacie A. Hathaway, Michael Hobbs, Jennifer Kingston, A. Launer, Tritia A. Matsuda, Jeremy B. Sebes, C. Vaughn, Elise WatsonThe influence of species life history and distribution characteristics on species responses to habitat fragmentation in an urban landscape
Fragmentation within urbanized environments often leads to a loss of native species diversity; however, variation exists in responses among-species and among-populations within species.We aimed to identify patterns in species biogeography in an urbanized landscape to understand anthropogenic effects on vertebrate communities and identify species that are more sensitive or resilient to landscape chAuthorsStaci M. Amburgey, David A. W. Miller, Carlton J. Rochester, Katy S. Delaney, Seth P. D. Riley, Cheryl S. Brehme, Stacie A. Hathaway, Robert N. FisherTrack tube construction and field protocol for small mammal surveys with emphasis on the endangered Pacific pocket mouse (Perognathus longimembris pacificus)
Track tubes are used to identify small animals by their tracks. Animals that are small enough to fit into the tubes walk over ink pads and onto cardstock paper to obtain bait within the tube, leaving their footprints. The tracking tubes described in this document are designed to be set on the ground with free access and exit at either end with additional design components for stability, durabilityAuthorsCheryl S. Brehme, Tritia A. Matsuda, Devin T. Adsit-Morris, Denise R. Clark, Jeremy B. Sebes, Melanie Anne T. Burlaza, Robert N. FisherQuantifying climate sensitivity and climate-driven change in North American amphibian communities
Changing climate will impact species’ ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >500,000 time-series observations for 81 species across 8AuthorsDavid A.W. Miller, Evan H. Campbell Grant, Erin L. Muths, Staci M. Amburgey, M. J. Adams, Maxwell B. Joseph, J. Hardin Waddle, Pieter T.J. Johnson, Maureen E. Ryan, Benedikt R. Schmidt, Daniel L. Calhoun, Courtney L. Davis, Robert N. Fisher, David M. Green, Blake R. Hossack, Tracy A.G. Rittenhouse, Susan C. Walls, Larissa L. Bailey, Sam S. Cruickshank, Gary M. Fellers, Thomas A. Gorman, Carola A. Haas, Ward Hughson, David S. Pilliod, Steven J. Price, Andrew M. Ray, Walter Sadinski, Daniel Saenz, William J. Barichivich, Adrianne B. Brand, Cheryl S. Brehme, Rosi Dagit, Katy S. Delaney, Brad M. Glorioso, Lee B. Kats, Patrick M. Kleeman, Christopher Pearl, Carlton J. Rochester, Seth P. D. Riley, Mark F. Roth, Brent SigafusByEcosystems Mission Area, Water Resources Mission Area, Species Management Research Program, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, John Wesley Powell Center for Analysis and Synthesis, Northern Rocky Mountain Science Center, South Atlantic Water Science Center (SAWSC), Southwest Biological Science Center, Upper Midwest Environmental Sciences Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research CenterEffects of urbanization, and habitat composition on site occupancy of two snake species using regional monitoring data from southern California
Detection data from a regional, reptile-monitoring program conducted by the U.S. Geological Survey were analyzed to understand the effects of urbanization and habitat composition on site occupancy of the coachwhip (Masticophis flagellum) and striped racer (M. lateralis) in coastal southern California. Likelihood-based occupancy models indicated striped racers responded to habitat composition, favoAuthorsMilan J. Mitrovich, James E. Diffendorfer, Cheryl S. Brehme, Robert N. FisherAn objective road risk assessment method for multiple species: ranking 166 reptiles and amphibians in California
ContextTransportation and wildlife agencies may consider the need for barrier structures and safe wildlife road-crossings to maintain the long-term viability of wildlife populations. In order to prioritize these efforts, it is important to identify species that are most at risk of extirpation from road-related impacts.PurposeOur goal was to identify reptiles and amphibians in California most susceAuthorsCheryl S. Brehme, Stacie A. Hathaway, Robert N. FisherLongevity and population age structure of the arroyo southwestern toad (Anaxyrus californicus) with drought implications
The arroyo southwestern toad is a specialized and federally endangered amphibian endemic to the coastal plains and mountains of central and southern California and northwestern Baja California. It is largely unknown how long these toads live in natural systems, how their population demographics vary across occupied drainages, and how hydrology affects age structure. We used skeletochronology to esAuthorsRobert N. Fisher, Cheryl S. Brehme, Stacie A. Hathaway, Tim E. Hovey, Manna L. Warburton, Drew C. StokesAn improved camera trap for amphibians, reptiles, small mammals, and large invertebrates
Camera traps are valuable sampling tools commonly used to inventory and monitor wildlife communities but are challenged to reliably sample small animals. We introduce a novel active camera trap system enabling the reliable and efficient use of wildlife cameras for sampling small animals, particularly reptiles, amphibians, small mammals and large invertebrates. It surpasses the detection ability ofAuthorsMichael T. Hobbs, Cheryl S. BrehmeMetabarcoding of fecal samples to determine herbivore diets: A case study of the endangered Pacific pocket mouse
Understanding the diet of an endangered species illuminates the animal’s ecology, habitat requirements, and conservation needs. However, direct observation of diet can be difficult, particularly for small, nocturnal animals such as the Pacific pocket mouse (Heteromyidae: Perognathus longimembris pacificus). Very little is known of the dietary habits of this federally endangered rodent, hindering mAuthorsDeborah D. Iwanowicz, Amy G. Vandergast, Robert S. Cornman, Cynthia R. Adams, Joshua R. Kohn, Robert N. Fisher, Cheryl S. BrehmePermeability of roads to movement of scrubland lizards and small mammals
A primary objective of road ecology is to understand and predict how roads affect connectivity of wildlife populations. Road avoidance behavior can fragment populations, whereas lack of road avoidance can result in high mortality due to wildlife-vehicle collisions. Many small animal species focus their activities to particular microhabitats within their larger habitat. We sought to assess how diffAuthorsCheryl S. Brehme, Jeff A. Tracey, Leroy R. McClenaghan, Robert N. FisherJoint estimation of habitat dynamics and species interactions: Disturbance reduces co-occurrence of non-native predators with an endangered toad
1. Ecologists have long been interested in the processes that determine patterns of species occurrence and co-occurrence. Potential short-comings of many existing empirical approaches that address these questions include a reliance on patterns of occurrence at a single time point, failure to account properly for imperfect detection and treating the environment as a static variable.2. We fit detectAuthorsDavid A.W. Miller, Cheryl S. Brehme, James E. Hines, James D. Nichols, Robert N. FisherEffects of large-scale wildfire on ground foraging ants (Hymenoptera: Formicidae) in southern California
We investigated the effect of broad-scale wildfire on ground foraging ants within southern California. In October and November of 2003, two wildfires burned large portions of the wildlands within San Diego County. Between January 2005 and September 2006, we surveyed 63 plots across four sites to measure the effect of the fires on the ant assemblages present in four vegetation types: 1) coastal sagAuthorsTritia Matsuda, Greta Turschak, Cheryl Brehme, Carlton Rochester, Milan Mitrovich, Robert Fisher - News