Robert N Fisher
Dr. Robert Fisher is a conservation biologist with the US 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.
- 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
- Conservation biology
- Natural history
- Invasive species
- Climate variability
Science and Products
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 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...
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...
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...
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...
Assessing effects of nonnative crayfish on mosquito survival
Introductions of nonnative predators often reduce biodiversity and affect natural predator–prey relationships and may increase the abundance of potential disease vectors (e.g., mosquitoes) indirectly through competition or predation cascades. The Santa Monica Mountains (California, U.S.A.), situated in a global biodiversity hotspot, is an area of...Bucciarelli, Gary M.; Suh, Daniel; Davis Lamb, Avery; Roberts, Dave; Sharpton, Debra; Shaffer, H. Bradley; Fisher, Robert N.; Kats, Lee B.
The Introduced Argentine ant (Linepithema humile) on the California Channel Islands: Distribution and Patterns of Spread
The Argentine ant (Linepithema humile) is a widespread and abundant introduced species that disrupts ecosystems throughout its introduced range. This invader was inadvertently introduced to Santa Catalina, San Clemente, Santa Cruz, and San Nicolas Islands at various points during the past century but currently appears to be absent from the...Boser, Christina L.; Merrell, Korie; Fisher, Robert N.; Naughton, Ida; Holway, David A
Multi-scale effects of land cover and urbanization on the habitat suitability of an endangered toad
Habitat degradation, entwined with land cover change, is a major driver of biodiversity loss. Effects of land cover change on species can be direct (when habitat is converted to alternative land cover types) or indirect (when land outside of the species habitat is altered). Hydrologic and ecological connections between terrestrial and...Treglia, Michael L.; Landon, Adam C; Fisher, Robert N.; Kyle, Gerard; Fitzgerald, Lee A.
Identifying management-relevant research priorities for responding to disease-associated amphibian declines
A research priority can be defined as a knowledge gap that, if resolved, identifies the optimal course of conservation action. We (a group of geographically distributed and multidisciplinary research scientists) used tools from nominal group theory and decision analysis to collaboratively identify and prioritize information...Campbell Grant, Evan H.; Adams, M.J.; Fisher, Robert N.; Grear, Daniel A.; Halstead, Brian J.; Hossack, Blake R.; Muths, Erin L.; Richgels, Katherine L. D.; Russell, Robin E.; Smalling, Kelly L.; Waddle, J. Hardin; Walls, Susan C.; White, C. LeAnn
Quantifying 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 >...Miller, David A.W.; Campbell Grant, Evan H.; Muths, Erin L.; Amburgey, Staci M.; Adams, M.J.; Joseph, Maxwell B.; Waddle, J. Hardin; Johnson, Pieter T.J.; Ryan, Maureen E.; Schmidt, Benedikt R.; Calhoun, Daniel L.; Davis, Courtney L.; Fisher, Robert N.; Green, David M.; Hossack, Blake R.; Rittenhouse, Tracy A.G.; Walls, Susan C.; Bailey, Larissa L.; Cruickshank, Sam S.; Fellers, Gary M.; Gorman, Thomas A.; Haas, Carola A.; Hughson, Ward; Pilliod, David S.; Price, Steven J.; Ray, Andrew M.; Sadinski, Walter; Saenz, Daniel; Barichivich, William J.; Brand, Adrianne B,; Brehme, Cheryl S.; Dagit, Rosi; Delaney, Katy S.; Glorioso, Brad M.; Kats, Lee B.; Kleeman, Patrick M.; Pearl, Christopher; Rochester, Carlton J.; Riley, Seth P. D.; Roth, Mark F.; Sigafus, Brent
Prioritizing conserved areas threatened by wildfire and fragmentation for monitoring and management
In many parts of the world, the combined effects of habitat fragmentation and altered disturbance regimes pose a significant threat to biodiversity. This is particularly true in Mediterranean-type ecosystems (MTEs), which tend to be fire-prone, species rich, and heavily impacted by human land use. Given the spatial complexity of overlapping...Tracey, Jeff A.; Rochester, Carlton J.; Hathaway, Stacie A.; Preston, Kristine L.; Syphard, Alexandra D.; Vandergast, Amy G.; Diffendorfer, James E.; Franklin, Janet; MacKenzie, Jason B.; Oberbauer, Tomas A.; Tremor, Scott; Winchell, Clark S.; Fisher, Robert N.
Effects 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...Mitrovich, Milan J.; Diffendorfer, James E.; Brehme, Cheryl S.; Fisher, Robert N.
All is not lost: Herpetofaunal “extinctions” in the Fiji Islands
Invasive mammals are implicated in the decline or extinction of numerous insular vertebrate species worldwide, yet rediscoveries of supposedly extinct vertebrates occur regularly. In particular, recent records of secretive amphibian and reptile taxa in the Fiji Islands show that earlier claimed extirpations of Fijian wildlife were erroneous. We...Clause, Adam G.; Thomas-Moko, Nunia; Rasalato, Sialisi; Fisher, Robert N.
Insular biogeographic origins and high phylogenetic distinctiveness for a recently depleted lizard fauna from Christmas Island, Australia
Striking faunal turnover across Asia and Australasia, most famously along the eastern edge of the Sunda Shelf or ‘Wallace's Line’, has been a focus of biogeographic research for over 150 years. Here, we investigate the origins of a highly threatened endemic lizard fauna (four species) on Christmas Island. Despite occurring less 350 km south of the...Oliver, Paul M.; Blom, Mozes P. K.; Cogger, Harold G.; Fisher, Robert N.; Richmond, Jonathan Q.; Woinarski, John C. Z.
An 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...Brehme, Cheryl S.; Hathaway, Stacie A.; Fisher, Robert N.
Longevity 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...Fisher, Robert N.; Brehme, Cheryl S.; Hathaway, Stacie A.; Hovey, Tim E.; Warburton, Manna L.; Stokes, Drew C.
Golden eagle (Aquila chrysaetos) habitat selection as a function of land use and terrain, San Diego County, California
Beginning in 2014, the U.S. Geological Survey, in collaboration with Bloom Biological, Inc., began telemetry research on golden eagles (Aquila chrysaetos) captured in the San Diego, Orange, and western Riverside Counties of southern California. This work was supported by the San Diego Association of Governments, California Department of Fish and...Tracey, Jeff A.; Madden, Melanie C.; Bloom, Peter H.; Katzner, Todd E.; Fisher, Robert N.
Southern California's fire ecology is unlike that of anywhere else in the United States. Fire control strategies developed for mountain forests don't have the same results here. So can science help uncover new answers to help Southern California communities manage and live with wildfires? This 11 minute film showcases ongoing USGS research supporting agencies on the...
Biologist Robert Fisher tells a troubling tale of how wildfire in Southern California has disrupted the lives of frogs, shrews, fish, and salamanders (despite the latter's mythical fondness of flame).
Adam Backlin, USGS Ecologist, talks about the potential dangers to the aquatic life in the streams around the Santa Ana Mountains as a result of the 2007 California wildfires.
Robert Fisher, USGS Research Biologist talks about the overall impact of fires on the biology of the area.
USGS Biologist, Robert Fisher, talks about the invasive species growing within the areas devastated by the 2007 California wildfires.
A screenshot from the USGS film "Living with Fire".
"Living with Fire" is a 11-minute USGS production exploring ongoing USGS research on wildfire science in southern California -- where the fire ecology is unlike any other region in the United States.
USGS is investigating ways to balance community fire risk management and native habitat conservation as part...
As wildlife diseases increase globally, an understanding of host-pathogen relationships can elucidate avenues for management and improve conservation efficacy. Amphibians are among the most threatened groups of wildlife, and disease is a major factor in global amphibian declines.
Amphibian species and community richness has been declining in North America and climate change may play a role in these declines. Global climate change has led to a range shift of many wildlife species and thus understanding how these changes in species distribution can be used to predict amphibian community responses that may improve conservation efforts.
Researchers from the U.S. Geological Survey, Taronga Conservation Society Australia, The National Trust of Fiji and NatureFiji-MareqetiViti have discovered a new species of banded iguana.
New Research Confirms Continued, Unabated and Large-Scale Amphibian Declines: Local Action Key to Reversing Losses
New U.S. Geological Survey-led research suggests that even though amphibians are severely declining worldwide, there is no smoking gun – and thus no simple solution – to halting or reversing these declines.