Robert N Fisher
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
Efficient 3D movement-based kernel density estimator and application to wildlife ecology
Correction of locality records for the endangered arroyo toad (Anaxyrus californicus) from the desert region of southern California
Comparative microhabitat characteristics at oviposition sites of the California red-legged frog (Rana draytonii)
New host and distributional records for Cryptosporidium sp. (Apicomplexa: Cryptosporidiidae) from lizards (Sauria: Gekkonidae, Scincidae) from the Cook Islands and Vanuatu, South Pacific
Two new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from emerald tree skinks, Lamprolepis smaragdina (Lesson) (Sauria: Scincidae) from Papua New Guinea and the Philippines
Permeability of roads to movement of scrubland lizards and small mammals
Two new species of Isospora (Apicomplexa: Eimeriidae) from skinks Emoia spp. (Sauria: Scincidae), from Fiji and Papua New Guinea
Evolutionary dynamics of a rapidly receding southern range boundary in the threatened California red-legged frog (Rana draytonii)
A new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from Carlia spp. (Sauria: Scincidae) from Papua New Guinea
Effects of natural flooding and manual trapping on the facilitation of invasive crayfish-native amphibian coexistence in a semi-arid perennial stream
Comparative phylogeography reveals deep lineages and regional evolutionary hotspots in the Mojave and Sonoran Deserts
Trends in amphibian occupancy in the United States
Science and Products
- Science
- Data
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Filter Total Items: 279
Efficient 3D movement-based kernel density estimator and application to wildlife ecology
We describe an efficient implementation of a 3D movement-based kernel density estimator for determining animal space use from discrete GPS measurements. This new method provides more accurate results, particularly for species that make large excursions in the vertical dimension. The downside of this approach is that it is much more computationally expensive than simpler, lower-dimensional models.AuthorsJeff Tracey-PR, James K. Sheppard, Glenn K. Lockwood, Amit Chourasia, Mahidhar Tatineni, Robert N. Fisher, Robert S. SinkovitsCorrection of locality records for the endangered arroyo toad (Anaxyrus californicus) from the desert region of southern California
The recovery strategy for an endangered species requires accurate knowledge of its distribution and geographic range. Although the best available information is used when developing a recovery plan, uncertainty often remains in regard to a species actual geographic extent. The arroyo toad (Anaxyrus californicus) occurs almost exclusively in coastal drainages, from Monterey County, California, soutAuthorsEdward L. Ervin, Kent R. Beaman, Robert N. FisherComparative microhabitat characteristics at oviposition sites of the California red-legged frog (Rana draytonii)
We studied the microhabitat characteristics of 747 egg masses of the federally-threatened Rana draytonii (California red-legged frog) at eight sites in California. our study showed that a broad range of aquatic habitats are utilized by ovipositing R. draytonii, including sites with perennial and ephemeral water sources, natural and constructed wetlands, lentic and lotic hydrology, and sites surrouAuthorsJeff A. Alvarez, David G. Cook, Julie L. Yee, Michael G. van Hattem, Darren R. Fong, Robert N. FisherNew host and distributional records for Cryptosporidium sp. (Apicomplexa: Cryptosporidiidae) from lizards (Sauria: Gekkonidae, Scincidae) from the Cook Islands and Vanuatu, South Pacific
Between 1991 and 1993, 295 lizards, comprising 21 species in 2 families (Gekkonidae, Scincidae) from the Cook Islands, Fiji, Palau, Takapoto, and Vanuatu in the South Pacific, were examined for Cryptosporidium oocysts. Only 6 lizards (2%) were found to be passing Cryptosporidium oocysts in their feces, including 2 of 30 (7%) Oceania geckos, Gehyra oceanica, from Rarotonga, Cook Islands, and 4 of 2AuthorsChris T. McAllister, Donald W. Duszynski, Robert N. FisherTwo new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from emerald tree skinks, Lamprolepis smaragdina (Lesson) (Sauria: Scincidae) from Papua New Guinea and the Philippines
Two new species of Eimeria Schneider, 1875, from emerald tree skinks, Lamprolepis smaragdina (Lesson) are described from specimens collected in Papua New Guinea (PNG) and the Philippines. Oöcysts of Eimeria nuiailan n. sp. from the only L. smaragdina from PNG are ovoidal, with a smooth, colourless, bi-layered wall, measure 23.7 × 19.1 μm, and have a length/width (L/W) ratio of 1.3; both micropyleAuthorsChris T. McAllister, R. Scott Seville, Donald W. Duszynski, Sarah E. Bush, Robert N. Fisher, Christopher C. AustinPermeability 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. FisherTwo new species of Isospora (Apicomplexa: Eimeriidae) from skinks Emoia spp. (Sauria: Scincidae), from Fiji and Papua New Guinea
Between September and October 1991 and again during September 1992, skinks (Emoia spp.) were collected from various localities on Fiji and Papua New Guinea (PNG) and examined for coccidians. One of 4 (25%) De Vis' emo skinks (Emoia pallidiceps) from PNG harbored an undescribed species of Isospora in its feces. Oocysts of Isospora grinbikpelapalai n. sp. were ellipsoidal to subspheroidal, 18.1 × 14AuthorsChris T. McAllister, Donald W. Duszynski, Robert N. FisherEvolutionary dynamics of a rapidly receding southern range boundary in the threatened California red-legged frog (Rana draytonii)
Populations forming the edge of a species range are often imperiled by isolation and low genetic diversity, with proximity to human population centers being a major determinant of edge stability in modern landscapes. Since the 1960s, the California red-legged frog (Rana draytonii) has undergone extensive declines in heavily urbanized southern California, where the range edge has rapidly contractedAuthorsJonathan Q. Richmond, Kelly R. Barr, Adam R. Backlin, Amy G. Vandergast, Robert N. FisherA new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from Carlia spp. (Sauria: Scincidae) from Papua New Guinea
A new species of Eimeria Schneider, 1875 from rainbow skinks, Carlia ailanpalai Zug and Carlia eothen Zug is described from specimens collected in Papua New Guinea (PNG). Oöcysts of Eimeria zugi n. sp. from one of one (100%) C. eothen are ellipsoidal to cylindroidal, with a smooth, colourless, bi-layered wall, measure 25.1 × 15.5 μm and have a length/width ratio of 1.6. The micropyle and the oöcysAuthorsChris T. McAllister, Donald W. Duszynski, Robert N. Fisher, Christopher C. AustinEffects of natural flooding and manual trapping on the facilitation of invasive crayfish-native amphibian coexistence in a semi-arid perennial stream
Aquatic amphibians are known to be vulnerable to a myriad of invasive predators. Invasive crayfish are thought to have eliminated native populations of amphibians in some streams in the semi-arid Santa Monica Mountains of southern California. Despite their toxic skin secretions that defend them from native predators, newts are vulnerable to crayfish attacks, and crayfish have been observed attackiAuthorsLee B. Kats, Gary Bucciarelli, Thomas L. Vandergon, Rodney L. Honeycutt, Evan Mattiasen, Arthur Sanders, Seth P.D. Riley, Jacob L. Kerby, Robert N. FisherComparative phylogeography reveals deep lineages and regional evolutionary hotspots in the Mojave and Sonoran Deserts
Aim: We explored lineage diversification within desert-dwelling fauna. Our goals were (1) to determine whether phylogenetic lineages and population expansions were consistent with younger Pleistocene climate fluctuation hypotheses or much older events predicted by pre-Pleistocene vicariance hypotheses, (2) to assess concordance in spatial patterns of genetic divergence and diversity among speciesAuthorsDustin A. Wood, Amy G. Vandergast, Kelly R. Barr, Richard D. Inman, Todd C. Esque, Kenneth E. Nussear, Robert N. FisherTrends in amphibian occupancy in the United States
Though a third of amphibian species worldwide are thought to be imperiled, existing assessments simply categorize extinction risk, providing little information on the rate of population losses. We conducted the first analysis of the rate of change in the probability that amphibians occupy ponds and other comparable habitat features across the United States. We found that overall occupancy by amphiAuthorsM. J. Adams, David A.W. Miller, Erin Muths, Paul Stephen Corn, Evan H. Campbell Grant, Larissa L. Bailey, Gary M. Fellers, Robert N. Fisher, Walter J. Sadinski, Hardin Waddle, Susan C. Walls - News
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