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
Pacific Pocket Mouse Monitoring and Research Program
Reptile and Amphibian Road Ecology
Species Observations from Pitfall Trap Arrays, Species Pool Matrices, and Patch Locations in Southern California from 1995-2015
Masticophis occupancy in southern California, 1995-2000
Research to inform passage spacing for migratory amphibians and to evaluate efficacy and designs for open elevated road segment (ERS) passages
Range-wide persistence of the endangered arroyo toad (Anaxyrus californicus) for 20+ years following a prolonged drought
Impacts of a non-indigenous ecosystem engineer, the American beaver (Castor canadensis), in a biodiversity hotspot
Non-native species having high per capita impacts in invaded communities are those that modulate resource availability and alter disturbance regimes in ways that are biologically incompatible with the native biota. In areas where it has been introduced by humans, American beaver (Castor canadensis) is an iconic example of such species due to its capacity to alter trophic dynamics of entire ecosyst
Responses of migratory amphibians to barrier fencing inform the spacing of road underpasses: A case study with California tiger salamanders (Ambystoma californiense) in Stanford, CA, USA
Research to inform Caltrans best management practices for reptile and amphibian road crossings
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
Science and Products
- Science
Pacific Pocket Mouse Monitoring and Research Program
Once thought to be extinct, the Pacific pocket mouse (Perognathus longimembris pacificus) was rediscovered in 1993 and is currently found at three population sites along the southern California coast. USGS researchers and their partners developed a comprehensive long-term monitoring plan to assess the status and trends of Pacific pocket mouse and identify important drivers of population dynamics...Reptile and Amphibian Road Ecology
USGS is working with many partners to help reptiles, amphibians and other animals cross roads safely, improving access to essential habitat. - Data
Species Observations from Pitfall Trap Arrays, Species Pool Matrices, and Patch Locations in Southern California from 1995-2015
Observations (reduced to detected/not detected) of 45 vertebrate species (seven mammals, seven amphibians, and 31 reptiles) across Southern California pitfall sampling projects conducted between 1995 through 2015. Habitat patch locations of every pitfall sampling project presented in a shapefile. Habitat patches were measured based on the size when pitfall sampling began within each. Sampling projMasticophis occupancy in southern California, 1995-2000
These data are CSV files comprised of a heading and tables from Appendix 1 and Appendix 2 in the accompanying paper. The tables show the sampling dates and locations for the coachwhip (Masticophis flagellum) and striped racer (Masticophis lateralis) in pit-fall arrays (Fisher et al. 2008) monitored in southern California from 1995-2000. GPS data are shown in decimal degrees and were collected in t - Publications
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Research to inform passage spacing for migratory amphibians and to evaluate efficacy and designs for open elevated road segment (ERS) passages
This is a multifaceted project that includes three main areas of research targeted to inform effective crossing systems for migratory amphibians, a large group of species which are at very high risk from negative impacts from roads within their habitats (Glista et al. 2008, Hamer and McDonnell 2008, Semlitsch 2008, Brehme et al. 2018). The three projects presented in this report are:1) Movement diRange-wide persistence of the endangered arroyo toad (Anaxyrus californicus) for 20+ years following a prolonged drought
Prolonged drought due to climate change has negatively impacted amphibians in southern California, U.S.A. Due to the severity and length of the current drought, agencies and researchers had growing concern for the persistence of the arroyo toad (Anaxyrus californicus), an endangered endemic amphibian in this region. Range-wide surveys for this species had not been conducted for at least 20 years.Impacts of a non-indigenous ecosystem engineer, the American beaver (Castor canadensis), in a biodiversity hotspot
Non-native species having high per capita impacts in invaded communities are those that modulate resource availability and alter disturbance regimes in ways that are biologically incompatible with the native biota. In areas where it has been introduced by humans, American beaver (Castor canadensis) is an iconic example of such species due to its capacity to alter trophic dynamics of entire ecosyst
Responses of migratory amphibians to barrier fencing inform the spacing of road underpasses: A case study with California tiger salamanders (Ambystoma californiense) in Stanford, CA, USA
Migratory amphibians are at high risk of negative impacts when roads intersect their upland and breeding habitats. Road mortality can reduce population abundance, survivorship, breeding, recruitment, and probability of long-term persistence. Increasingly, environmental planners recommend installation of under-road tunnels with barrier fencing to reduce mortality and direct amphibians towards the pResearch 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 mappTrack 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, durabilityQuantifying 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 8ByEcosystems, Water Resources, Species Management Research Program, Patuxent Wildlife Research Center, 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, favoAn 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 susceLongevity 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 esAn 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 ofMetabarcoding 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 m - News
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