Dr. Robert Fisher is a conservation biologist with the U.S. Geological Survey’s Western Ecological Research Center and works as part of a large integrated team.
His focus has been on how natural systems are responding to the Anthropocene, and what types of resiliency they have or lack as it relates to maintaining ecological integrity and biodiversity. Additionally, through understanding individual species and community responses to perturbations through modern monitoring techniques, he and his team can determine appropriate management experiments or options to possibly recover resiliency. Geographically they have two foci, the first is southern California where urbanization and conservation planning bring various direct and indirect drivers of ecological change, and climate variability is currently extreme and drives landscape level drought and wildfires. Their second foci are the tropical islands of the Pacific Basin, from Palau and Papua New Guinea east to Hawai’i. These islands have also been driven by human change and are on the front line as extreme recent weather variability in the cyclone belt impact terrestrial ecosystems. Understanding how biodiversity was generated in this ecoregion is critical to managing its loss, and their team focuses across time and space (biogeography) to understand these processes utilizing molecular tools tied to expeditions of discovery in this poorly studied ecoregion.
RESEARCH INTERESTS
- Conservation biology
- Biogeography
- Modelling
- Natural history
- Speciation
- Invasive species
- Climate variability
- Anthropocene
Education and Certifications
Ph.D., Population Biology, University of California, Davis, CA 1995
M.S., Zoology, University of California, Davis, CA 1991
B.S., Biology, University of California, Irvine, CA 1988
Science and Products
Pacific Pocket Mouse Monitoring and Research Program
Reptile and Amphibian Road Ecology
WERC Fire Science
Amphibian Research in Southern California
Golden Eagles in Coastal Southern California
Reptile Biodiversity in the Pacific Basin Islands
San Diego Field Station
Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models
Western Spadefoot Survey Data in Northern and Central California (2019)
Long-distance movements of non-migratory golden eagles in western North America, 2007-2017
Detection/non-detection data on territorial pairs of golden eagles in coastal southern California, 2016-2017
Western Spadefoot Habitat Selection Based on Radio Telemetry in Orange County, California 2019
Species Observations from Pitfall Trap Arrays, Species Pool Matrices, and Patch Locations in Southern California from 1995-2015
Amphibian capture mark-recapture
Masticophis occupancy in southern California, 1995-2000
Predictor, null model, response variable, and habitat suitability prediction rasters for a golden eagle hierarchical Bayesian synoptic model used for habitat selection in San Diego County, California. Derived from golden eagle data collected from November
Loss of dendritic connectivity in southern Californias urban riverscape facilitates decline of an endemic freshwater fish
New record of California red-legged frogs (Rana draytonii) in Whitewater Canyon, Riverside County, CA, USA
Data release for persistence of historical population structure in an endangered species despite near-complete biome conversion in Californias San Joaquin Desert
Multi-scale patterns in occurrence of an ephemeral pool-breeding amphibian
Defining relevant conservation targets for the endangered Southern California distinct population segment of the mountain yellow-legged frog (Rana muscosa)
Impacts of a non-indigenous ecosystem engineer, the American beaver (Castor canadensis), in a biodiversity hotspot
Reproductive plasticity as an advantage of snakes during island invasion
Range eclipse leads to tenuous survival of a rare lizard species on a barrier atoll
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
Could climate change benefit invasive snakes? Modelling the potential distribution of the California Kingsnake in the Canary Islands
Conservation of northwestern and southwestern pond turtles: Threats, population size estimates, and population viability analysis
Conservation implications of spatiotemporal variation in the terrestrial ecology of Western spadefoots
Reptile and amphibian diversity and abundance in an urban landscape: Impacts of fragmentation and the conservation value of small patches
Western pond turtles in the Mojave Desert? A review of their past, present, and possible future
Linking behavioral states to landscape features for improved conservation management
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.WERC Fire Science
WERC scientists are defining the past, present, and future of wildfires for wildlife and human communities. Explore this webpage to learn about specific, ongoing projects across California and parts of Nevada.Amphibian Research in Southern California
Amphibian populations have declined in many areas around the world. Initially, there was skepticism as to whether the observed declines were merely minor population fluctuations, but it has become increasingly clear that many declines are both real and sustained. At the request of the U.S. Department of the Interior, USGS Western Ecological Research Center (WERC) scientists are supporting the...Golden Eagles in Coastal Southern California
The status of the golden eagle (Aquila chrysaetos) in coastal southern California is unclear. To address this knowledge gap, Dr. Robert Fisher in collaboration with local, State and other Federal agencies begin a multi-year survey and tracking program of golden eagles to address questions regarding habitat use, movement behavior, nest occupancy, genetic population structure, and human impacts on...Reptile Biodiversity in the Pacific Basin Islands
Dr. Robert Fisher and his colleagues have teamed up with the U.S. Fish and Wildlife, The Nature Conservancy and multiple universities to conduct several types of studies that will address high priority issues related to reptiles in the Pacific Basin Islands. These studies will provide new information about species diversity, endemicity, biology and demography of reptile fauna and will lay the...San Diego Field Station
The San Diego Field Station is the site of research on golden eagles, endangered amphibians and reptiles, and more. Click on the "Science" tab for a comprehensive summary of this study site's projects.Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models
Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines across - Data
Western Spadefoot Survey Data in Northern and Central California (2019)
Species distributions are governed by processes occurring at multiple spatial scales. For species with complex life cycles, the needs of all life stages must be met within the dispersal limitations of the species. Multi-scale processes can be particularly important for these species, where small-scale patterns in specific habitat components can affect the distribution of one life stage, whereas laLong-distance movements of non-migratory golden eagles in western North America, 2007-2017
We studied >500 golden eagles tracked by telemetry over a 10-year period in western North America, of which 160 engaged in non-routine, long-distance (> 300 km) movements. We identified spatial and temporal correlates of those movements at both small and large scales, and we quantified movement timing and direction. We further tested which age and sex classes of eagles were more likely to engage iDetection/non-detection data on territorial pairs of golden eagles in coastal southern California, 2016-2017
This dataset contains detection-nondetection data for territorial pairs of Golden Eagles at survey sites randomly selected from a grid of equal-sized (13.9 km2) hexagonal sample cells overlaid across the region of interest in Coastal Southern California during 2016 and 2017. We partitioned surveys within seasons based on approximate transition dates for stages in the breeding cycle of golden eagleWestern Spadefoot Habitat Selection Based on Radio Telemetry in Orange County, California 2019
We conducted a radio telemetry study of adult western spadefoots (Spea hammondii) at 2 sites in southern California to characterize their survival, behavior, and movements from breeding through aestivation to inform conservation and management for the species. These data support the following publication: Halstead, B.J., Baumberger, K.L., Backlin, A.R., Kleeman, P.M., Wong, M.N., Gallegos, E.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 projAmphibian capture mark-recapture
These data represent capture mark recapture data along with associated disease status for boreal toads (Anaxyrus boreas) from Wyoming and Montana from 2004-2016 and four frog species (Rana draytonii, R. muscosa, R. pretiosa, R. sierrae) from 2001-2016.Masticophis 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 tPredictor, null model, response variable, and habitat suitability prediction rasters for a golden eagle hierarchical Bayesian synoptic model used for habitat selection in San Diego County, California. Derived from golden eagle data collected from November
This data release includes three types of data used in habitat modeling, and predictions from the habitat models. (1) Predictor rasters for proportion urban development within 1-km radius, proportion exurban within 1-km radius, vector ruggedness measure (VRM) within 500-m radius, topographic position index (TPI) within 500-m radius. (2) Twenty-nine null models for space use for 29 different goldenLoss of dendritic connectivity in southern Californias urban riverscape facilitates decline of an endemic freshwater fish
These data consist of microsatellite genotype scores for all samples of Santa Ana sucker (Catostomus santaanae) used in the study. Scores represent the allele calls for each microsatellite locus (i.e. DNA fragment length containing the microsatellite repeats), with each locus containing two scores representing the two allele copies detected. Included are five tables: Full dataset (includes genotypNew record of California red-legged frogs (Rana draytonii) in Whitewater Canyon, Riverside County, CA, USA
In February 2017, a population of California red-legged frog Rana draytonii was discovered in the southern foothills of the San Bernardino Mountains of Riverside County, California, near the edge of the species historic distribution. A few days after the first sightings of R. draytonii at the Whitewater Preserve, we conducted a visual daytime search for frogs, tadpoles and egg masses followed by aData release for persistence of historical population structure in an endangered species despite near-complete biome conversion in Californias San Joaquin Desert
The recency of large-scale land conversion in Californias San Joaquin Desert raises the probability that the regions numerous endemic species still retain genetic signatures of historical population connectivity. If so, genomic data can serve as a guidance tool for conserving lands that once supported habitat for gene movement. We studied the genetic structuring of the endangered blunt-nosed leopa - Multimedia
- Publications
Filter Total Items: 235
Multi-scale patterns in occurrence of an ephemeral pool-breeding amphibian
Species distributions are governed by processes occurring at multiple spatial scales. For species with complex life cycles, the needs of all life stages must be met within the dispersal limitations of the species. Multi-scale processes can be particularly important for these species, where small-scale patterns in specific habitat components can affect the distribution of one life stage, whereas laDefining relevant conservation targets for the endangered Southern California distinct population segment of the mountain yellow-legged frog (Rana muscosa)
Abstract The Endangered Sierra Madre yellow-legged frog (Rana muscosa) has been reduced to 80% of populations would be extinct 50 years later. Therefore, the species will not be able to persist without implementation of the reintroduction program. We found that it is more important to increase the number of suitable sites occupied by R. muscosa than to simply reinforce or augment existing populatiImpacts 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 ecosystReproductive plasticity as an advantage of snakes during island invasion
Most invasive species are not studied during their initial colonization of ecosystems to which they were recently introduced. Rather, research is typically performed after invasive species are well established and causing harm to the native biodiversity. Thus, novel adaptations of invasive species during their initial invasions are rarely identified. The California kingsnake (Lampropeltis californRange eclipse leads to tenuous survival of a rare lizard species on a barrier atoll
Rediscovery of living populations of a species that was presumed to be extirpated can generate new narratives for conservation in areas suffering from losses in biodiversity. We used field observations and DNA sequence data to verify the rediscovery of the Critically Endangered scincid lizard Emoia slevini on Dåno′, an islet off the coast of Guam in the southern Mariana Islands, where for > 20 yeaResponses 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 pCould climate change benefit invasive snakes? Modelling the potential distribution of the California Kingsnake in the Canary Islands
The interaction between climate change and biological invasions is a global conservation challenge with major consequences for invasive species management. However, our understanding of this interaction has substantial knowledge gaps; this is particularly relevant for invasive snakes on islands because they can be a serious threat to island ecosystems. Here we evaluated the potential influence ofConservation of northwestern and southwestern pond turtles: Threats, population size estimates, and population viability analysis
Accurate status assessments of long-lived, widely distributed taxa depend on the availability of long-term monitoring data from multiple populations. However, monitoring populations across large temporal and spatial scales is often beyond the scope of any one researcher or research group. Consequently, wildlife managers may be tasked with utilizing limited information from different sources to detConservation implications of spatiotemporal variation in the terrestrial ecology of Western spadefoots
Conservation of species reliant on ephemeral resources can be especially challenging in the face of a changing climate. Western spadefoots (Spea hammondii) are small burrowing anurans that breed in ephemeral pools, but adults spend the majority of their lives underground in adjacent terrestrial habitat. Western spadefoots are of conservation concern throughout their range because of habitat loss,Reptile and amphibian diversity and abundance in an urban landscape: Impacts of fragmentation and the conservation value of small patches
Urbanization is a major contributor to habitat loss and fragmentation and is considered a global threat to biodiversity. We studied reptile and amphibian species diversity and abundance in a highly fragmented landscape adjacent to the second largest metropolitan area in the United States. Habitat patches in our study area were made up of remnant native vegetation surrounded by roads, housing, andWestern pond turtles in the Mojave Desert? A review of their past, present, and possible future
=The western pond turtle (WPT) was formerly considered a single species (Actinemys or Emys marmorata) that ranged from southern British Columbia, Canada to Baja California, México. More recently it was divided into a northern and a southern species. WPTs are found primarily in streams that drain into the Pacific Ocean, although scattered populations exist in endorheic drainages of the Great BasinLinking behavioral states to landscape features for improved conservation management
A central theme for conservation is understanding how animals differentially use, and are affected by change in, the landscapes they inhabit. However, it has been challenging to develop conservation schemes for habitat-specific behaviors.Here we use behavioral change point analysis to identify behavioral states of golden eagles (Aquila chrysaetos) in the Sonoran and Mojave Deserts of the southwest - News
Filter Total Items: 13