Search USGS⌕ Search

Geology topics

Robert N. Fisher

Publications and source records attributed to Robert N. Fisher.

At least 91 records · Page 5Linked to original sources
USGS2021

Case 3853 – Eumeces niger Hombron & Jacquinot, 1853 (currently Emoia nigra) (Reptilia, Scincidae): proposed conservation of prevailing usage by setting aside a lectotype designation for Gongylus (Eumeces) freycineti Duméril & Bibron, 1839 (currently Emoia atrocostata freycineti)

The purpose of the present application, under Articles 74.1.1 and 81.1 of the Code, is to maintain consistent usage of the commonly used name Emoia nigra (Hombron & Jacquinot, 1853 ) by setting aside a lectotype designation for Gongylus ( Eumeces ) freycineti Duméril & Bibron, 1839 by Wells & Wellington in 1985 in favour of a later lectotype designation by Brown in 1991 .

The Bulletin of Zoological Nomenclature↗
USGS2021

The Coyote Mountains’ desert snail (Sonorelix harperi carrizoensis), a lazarus species With the first documentation of live individuals

The Coyote Mountain desert snail ( Sonorelix harperi carrizoensis ) was described in 1937 from 30 dry shells collected the previous year. We reviewed the literature and museum records and found two additional shell collections for this subspecies from the type locality one from 1958, and one from an adjacent mountain range in 1938. There is no evidence previously of any live snails being collected from the Coyote Mountains, Imperial County, California. All shell collections of S. harperi carrizoensis have the same locality data as the type series, which is Painted Gorge, Coyote Mountains except for one recorded collection of shells from the Vallecito Mountains from 1938. Using geological maps and other data sources, a potential mesic habitat was identified in the Coyote Mountains. During recent field work for salamanders at this location we detected two live specimens of S. harperi carrizoensis approximately 2 km north of its type location. This new data confirms this subspecies is still extant and has occurred at least at two sites historically in these mountains. Despite the presence of mesic habitats (i.e., mosses, liverworts and ferns) at the type locality, we found no evidence of S. harperi carrizoensis or salamanders.

California↗
USGS2021

Predictability of invasive Argentine ant distribution across Mediterranean ecoregions of southern California

The invasiveness of nonnative taxa can vary across a landscape due to environmental gradients, suggesting that location-dependent management strategies may be more effective at reducing spread compared to a “one size fits all” approach across the entire introduced range. Using bait stations placed along linear transects within habitat preserves, we tested for effects of ecoregion, vegetation, soil moisture, habitat edge type (i.e., moisture source), and distance from edges on the presence of the invasive Argentine ant Linepithema humile in San Diego County, California, a region with high indigenous biodiversity and numerous rare and protected species. Our results showed an inverse relationship between the presence of native ant species and the presence of the Argentine ant across ecoregions, with the latter reaching peak abundance in the coastal terrace. Argentine ant presence was negatively associated with distance from all edge types regardless of location, but the magnitude of this effect varied among ecoregions. In the xeric foothill and inland valleys, the probability of occurrence was nearly 0 at distances of 200 m and 750 m from moisture edges, respectively, whereas in the coastal terrace, the probability remained above 0.80 at distances up to 1.25 km. When compared to previous studies at different spatial scales, these findings provide an alternative perspective on the invasiveness of the Argentine ant at the landscape level. Our results further suggest that efforts to control spread in regions with a Mediterranean climate may be more successful in inland areas, where the ant is likely to have lower environmental tolerance and native ant species may be better able to generate biotic resistance. In contrast, different tactics and expectations may be necessary for coastal areas, where the same constraints are diminished or absent.

California↗
USGS2021

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 mapping tools that crosswalk with California Essential Habitat Connectivity Planning, and field research to address information gaps in the efficacy of reptile and amphibian passage and barrier systems. Per the agreement with California Department of Transportation (Caltrans; agreement 65A0553), this project was part of a broader collaborative effort between the Western Transportation Institute (WTI) of Montana State University and USGS Western Ecological Research Center (WERC). As part of this broader project, WTI conducted a worldwide literature review and gap analysis and produced the BMP manual for herpetofauna in California. WTI and USGS were contracted separately although we worked closely together throughout this broader effort and each brought particular expertise to the project. WTI has expertise in highways, the attributes of the highway environment, and has broad international experience with road ecology and herpetofauna connectivity systems worldwide. USGS WERC has expertise with California amphibian and reptile species and their ecology, study design and implementation, as well as expertise in landscape connectivity and road ecology.

California↗
USGS2021

Tarentola annularis (white-spotted wall gecko)

USA: CALIFORNIA: Orange Co.: San Juan Capistrano (33.51°N,117.66°W; WGS 84). 25 August 2020. Samuel Fisher, Chelsea Martin, Robert Fisher. Verified by Gregory B. Pauly. Natural History Museum of Los Angeles County (LACM 191974). New county record. One juvenile (33 mm SVL) was collected, and another juvenile was seen 40 m away. Another juvenile was also observed during a second visit to the site on 19 September 2020. Wall geckos were first documented at this site since at least 2019 by Gary Nafis (G. Nafis, pers. comm. and as posted on www.californiaherps.com; 23 Aug 2020). Given that multiple individuals were observed at this site over 2 mo, this appears to be an established population. Invasive T. annularis were first detected in California in Redlands, San Bernardino County in the early 2000s (Wilcox et al. 2014. Herpetol. Rev. 45:464). This new Orange County population is ca. 80 km SW of the other known California population. While T. annularis has not spread much in the downtown urban center in Redlands over the last 20 years (S. Fisher, unpubl. data), it is possible it might expand its range more rapidly in a less urbanized habitat if there were more landscaping and natural features present. The only other published records for North America are from Florida where they are also invasive, and they have been known since the 1990s from several locations and continued to spread (Krysko et al. 2016. IRCF Rept. Amphib. 23:110-143). In the native range of T. annularis their habitat consists of desert, indicating that even though they are able to breed and persist in coastal Orange County they may not be in the optimal habitat (Ibrahim 2004. Zool. Middle East 31:23–38). A potential concern is that if T. annularis becomes more widespread in Southern California, they could present a risk to endemic nocturnal rock-dwelling species such as Xantusia henshawi and Phyllodactylus nocticolus because T. annularis has been shown to engage in saurophagy (Ibrahim 2004, op. cit.). It is much larger than these species (X antusia henshawi SVL = 70 mm; Phyllodactylus nocticolus SVL = 63 mm; Tarentola SVL = 108 mm) and well adapted to desert habitats where it could be a potential predator or competitor.

California↗
USGS2021

Hemidactylus turcicus (Mediterranean Gecko). Endoparasite.

Hemidactylus turcicus is a native of western India, Somalia, the Middle East, and the Mediterranean region and is one of the most successful invasive species in the world (Kraus. 2009. Alien Reptiles and Amphibians: A Scientific Compendium and Analysis. Springer Verlag, Berlin. 563 pp.). Since its introduction into the USA via the Port of Miami, Florida, around 1915, the range of this gecko has increased to include much of southern North America from Virginia and Florida west to California (Meshaka et al. 2006. Herpetol. Conserv. Biol. 1:145–150). A summation of the helminth parasites of both introduced and native H. turcicus was provided by McAllister and Bursey (2016. Acta Parasitol. 61:576–584). Here, we document a new host record for a tapeworm parasite of an introduced H. turcicus.

Herpetological Review↗
USGS2020

Influence of niche breadth and position on the historical biogeography of seafaring scincid lizards

Niche breadth and position can influence diversification among closely related species or populations, yet limited empirical data exist concerning the predictability of the outcomes. We explored the effects of these factors on the evolution of the Emoia atrocostata species group, an insular radiation of lizards in the western Pacific Ocean and Indo-Australasia composed of both endemic and widespread species that differ in niche occupancy. We used molecular data and phylogeographical diffusion models to estimate the timing and patterns of range expansion, and ancestral reconstruction methods to infer shifts in ecology. We show evidence of multidirectional spread from a centre of origin in western Micronesia, and that the phyletic diversity of the group is derived from a putative habitat specialist that survives in the littoral zone. This species is composed of paraphyletic lineages that represent stages or possible endpoints in the continuum toward speciation. Several descendant species have transitioned to either strand or interior forest habitat, but only on remote islands with depauperate terrestrial faunas. Our results suggest that the atrocostata group might be in the early phases of a Wilsonian taxon cycle and that the capacity to tolerate salt stress has promoted dispersal and colonization of remote oceanic islands. Divergence itself, however, is largely driven by geographical isolation rather than shifts in ecology.

Biological Journal of the Linnean Society↗
USGS2020

A clarification on the effects of urbanization on Golden Eagle (Aquila chrysaetos) habitat selection

Introduction In 2018, the U.S. Geological Survey (USGS) published an Open-File Report ( Tracey and others, 2018 ) presenting a Bayesian habitat selection model for golden eagles ( Aquila chrysaetos ) in San Diego County, California. The model used telemetry data to examine the effects of urban development, exurban development, and topography (characterized by a topographic position index and a vector ruggedness measure, TPI and VRM respectively) on golden eagle habitat selection probability. Based on figures 3 and 6 of Tracey and others (2018) , we received inquiries from cooperators (U.S. Fish and Wildlife Service and California Department of Fish and Wildlife) about how the probability of eagle use declines with decreasing distance to the urban edge. Here, we clarify our results by addressing that question.

Open-File Report↗
USGS2020

Slender salamanders (genus Batrachoseps) reveal Southern California to be a center for the diversification, persistence, and introduction of salamander lineages

Background The southern California biodiversity hotspot has had a complex geological history, with both plate tectonic forces and sea level changes repeatedly reconfiguring the region, and likely driving both lineage splittings and extinctions. Here we investigate patterns of genetic divergence in two species of slender salamanders (Plethodontidae: Batrachoseps ) in this region. The complex geological history in combination with several organismal traits led us to predict that these species harbor multiple ancient mitochondrial lineages endemic to southern California. These species belong to a clade characterized by fine-scale mitochondrial structure, which has been shown to track ancient splits. Both focal species, Batrachoseps major and B. nigriventris , are relatively widely distributed in southern California, and estimated to have persisted there across millions of years. Recently several extralimital populations of Batrachoseps were found in the San Joaquin Valley of California, a former desert area that has been extensively modified for agriculture. The origins of these populations are unknown, but based on morphology, they are hypothesized to result from human-mediated introductions of B. major . Methods We sequenced the mitochondrial gene cytochrome b from a geographically comprehensive sampling of the mitochondrial lineages of B. major and B. nigriventris that are endemic to southern California. We used phylogenetic analyses to characterize phylogeographic structure and identify mitochondrial contact zones. We also included the San Joaquin Valley samples to test whether they resulted from introductions. We used a bootstrap resampling approach to compare the strength of isolation-by-distance in both Batrachoseps species and four other salamander species with which they co-occur in southern California. Results The northern lineage of B. major harbors at least eight deeply differentiated, geographically cohesive mitochondrial subclades. We identify geographic contact between many of these mtDNA lineages and some biogeographic features that are concordant with lineage boundaries. Batrachoseps nigriventris also has multiple deeply differentiated clades within the region. Comparative analyses highlight the smaller spatial scales over which mitochondrial divergence accumulates in Batrachoseps relative to most other salamander species in southern California. The extralimital populations of Batrachoseps from the San Joaquin Valley are assigned to B. major and are shown to result from at least two independent introductions from different source populations. We also suggest that B. major on Catalina Island, where it is considered native, may be the result of an introduction. Some of the same traits that facilitate the build-up of deep phylogeographic structure in Batrachoseps likely also contribute to its propensity for introductions, and we anticipate that additional introduced populations will be discovered.

California↗
USGS2020

Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians

The salamander chytrid fungus (Batrachochytrium salamandrivorans [Bsal]) is causing massive mortality of salamanders in Europe. The potential for spread via international trade into North America and the high diversity of salamanders has catalyzed concern about Bsal in the U.S. Surveillance programs for invading pathogens must initially meet challenges that include low rates of occurrence on the landscape, low prevalence at a site, and imperfect detection of the diagnostic tests. We implemented a large-scale survey to determine if Bsal was present in North America designed to target taxa and localities where Bsal was determined highest risk to be present based on species susceptibility and geography. Our analysis included a Bayesian model to estimate the probability of occurrence of Bsal given our prior knowledge of the occurrence and prevalence of the pathogen. We failed to detect Bsal in any of 11,189 samples from 594 sites in 223 counties within 35 U.S. states and one site in Mexico. Our modeling indicates that Bsal is highly unlikely to occur within wild amphibians in the U.S. and suggests that the best proactive response is to continue mitigation efforts against the introduction and establishment of the disease and to develop plans to reduce impacts should Bsal establish.

Continental United States↗
USGS2020

Biotelemetry data for Golden Eagles (Aquila chrysaetos) captured in coastal southern California, February 2017–December 2019

Because of a lack of clarity about the status of golden eagles ( Aquila chrysaetos ) in coastal southern California, the U.S. Geological Survey, in collaboration with U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, Bureau of Land Management, and San Diego Management and Monitoring Program, began 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 eagles. Golden eagle trapping and tracking efforts began in September 2014. During trapping efforts from September 29, 2014, to February 23, 2017, 37 golden eagles were captured. During trapping efforts from February 24, 2017, to December 2, 2019, an additional 7 golden eagles (4 females and 3 males) were captured, and one previously captured female was recaptured in San Diego County. Biotelemetry data for 27 of the 44 golden eagles that were transmitting data from February 24, 2017, to December 2, 2019, are presented. These eagles ranged as far north as British Columbia, Canada, and as far south as Ciudad Insurgentes, Baja California, Mexico.

California↗
USGS2020

Changes in capture rates and body size among vertebrate species occupying an insular urban habitat reserve

Long‐term ecological monitoring provides valuable and objective scientific information to inform management and decision‐making. In this article, we analyze 22 years of herpetofauna monitoring data from the Point Loma Ecological Conservation Area (PLECA), an insular urban reserve near San Diego, CA. Our analysis showed that counts of individuals for one of the four most common terrestrial vertebrates declined, whereas counts for other common species increased or remained stable. Two species exhibited declines in adult body length, whereas biomass pooled over the five most common species increased over time and was associated with higher wet season precipitation. Although the habitat and vegetation at PLECA have remained protected and intact, we suspect that changes in arthropod communities may be driving changes in the abundance, growth, and development of insectivorous lizards. This study underscores the value of long‐term monitoring for establishing quantitative baselines to assess biological changes that would otherwise go undetected.

California↗
USGS2020

Historical museum collections and contemporary population studies implicate roads and introduced predatory bullfrogs in the decline of western pond turtles

The western pond turtle (WPT), recently separated into two paripatrically distributed species ( Emys pallida and Emys marmorata ), is experiencing significant reductions in its range and population size. In addition to habitat loss, two potential causes of decline are female-biased road mortality and high juvenile mortality from non-native predatory bullfrogs ( Rana catesbeiana ). However, quantitative analyses of these threats have never been conducted for either species of WPT. We used a combination of historical museum samples and published and unpublished field studies shared with us through personal communications with WPT field researchers (B. Shaffer, P. Scott, R. Fisher, C. Brown, R. Dagit, L. Patterson, T. Engstrom, 2019, personal communications) to quantify the effect of roads and bullfrogs on WPT populations along the west coast of the United States. Both species of WPT shift toward increasingly male biased museum collections over the last century, a trend consistent with increasing, female-biased road mortality. Recent WPT population studies revealed that road density and proximity were significantly associated with increasingly male-biased sex ratios, further suggesting female-biased road mortality. The mean body size of museum collections of E. marmorata , but not E. pallida , has increased over the last 100 years, consistent with reduced recruitment and aging populations that could be driven by invasive predators. Contemporary WPT population sites that co-occur with bullfrogs had significantly greater average body sizes than population sites without bullfrogs, suggesting strong bullfrog predation on small WPT hatchlings and juveniles. Overall, our findings indicate that both species of WPT face demographic challenges which would have been difficult to document without the use of both historical data from natural history collections and contemporary demographic field data. Although correlational, our analyses suggest that female-biased road mortality and predation on small turtles by non-native bullfrogs are occurring, and that conservation strategies reducing both may be important for WPT recovery.

Baja California, California, Oregon, Washington↗
USGS2020

Establishment of brown anoles (Anolis sagrei) across a southern California county and potential interactions with a native lizard species

The brown anole, Anolis sagrei , is a native species to the Caribbean; however, A. sagrei has invaded multiple parts of the USA, including Florida, Louisiana, Hawai’i and more recently California. The biological impacts of A. sagrei invading California are currently unknown. Evidence from the invasion in Taiwan shows that they spread quickly and when immediate action is not taken eradication stops being a viable option. In Orange County, California, five urban sites, each less than 100 ha, were surveyed for an average of 49.2 min. Approximately 200 A. sagrei were seen and verified across all survey sites. The paucity of native lizards encountered during the surveys within these sites suggests little to no overlap between the dominant diurnal western fence lizard, Sceloporus occidentalis , and A. sagrei . This notable lack of overlap could indicate a potentially disturbing reality that A. sagrei are driving local extirpations of S. occidentalis .

California↗
USGS2020

Amphibian responses in the aftermath of extreme climate events

Climate change-induced extinctions are estimated to eliminate one in six known species by the end of the century. One major factor that will contribute to these extinctions is extreme climatic events. Here, we show the ecological impacts of recent record warm air temperatures and simultaneous peak drought conditions in California. From 2008–2016, the southern populations of a wide-ranging endemic amphibian (the California newt, Taricha torosa) showed a 20% reduction to mean body condition and significant losses to variation in body condition linked with extreme climate deviations. However, body condition in northern populations remained relatively unaffected during this period. Range-wide population estimates of change to body condition under future climate change scenarios within the next 50 years suggest that northern populations will mirror the loss of body condition recently observed in southern populations. This change is predicated on latter 21st century climate deviations that resemble recent conditions in Southern California. Thus, the ecological consequences of climate change have already occurred across the warmer, drier regions of Southern California, and our results suggest that predicted climate vulnerable regions in the more mesic northern range likely will not provide climate refuge for numerous amphibian communities.

California↗
USGS2020

Does the virus cross the road? Viral phylogeographic patterns among bobcat populations reflect a history of urban development

Urban development has major impacts on connectivity among wildlife populations and is thus likely an important factor shaping pathogen transmission in wildlife. However, most investigations of wildlife diseases in urban areas focus on prevalence and infection risk rather than potential effects of urbanization on transmission itself. Feline immunodeficiency virus (FIV) is a directly transmitted retrovirus that infects many felid species and can be used as a model for studying pathogen transmission at landscape scales. We investigated phylogenetic relationships among FIV isolates sampled from five bobcat ( Lynx rufus ) populations in coastal southern California that appear isolated due to major highways and dense urban development. Divergence dates among FIV phylogenetic lineages in several cases reflected historical urban growth and construction of major highways. We found strong FIV phylogeographic structure among three host populations north‐west of Los Angeles, largely coincident with host genetic structure. In contrast, relatively little FIV phylogeographic structure existed among two genetically distinct host populations south‐east of Los Angeles. Rates of FIV transfer among host populations did not vary significantly, with the lack of phylogenetic structure south‐east of Los Angeles unlikely to reflect frequent contemporary transmission among populations. Our results indicate that major barriers to host gene flow can also act as barriers to pathogen spread, suggesting potentially reduced susceptibility of fragmented populations to novel directly transmitted pathogens. Infrequent exchange of FIV among host populations suggests that populations would best be managed as distinct units in the event of a severe disease outbreak. Phylogeographic inference of pathogen transmission is useful for estimating the ability of geographic barriers to constrain disease spread and can provide insights into contemporary and historical drivers of host population connectivity.

California↗
USGS2020

Introgression obscures lineage boundaries and phylogeographic history in the western banded gecko, Coleonyx variegatus (Squamata: Eublepharidae)

The geomorphological formation of the Baja California peninsula and the Gulf of California is a principal driver of diversification for the reptiles of North America’s warm deserts. The western banded gecko, Coleonyx variegatus , is distributed throughout the Mojave, Sonoran and Peninsular deserts. In this study we use multilocus sequence data to address deep phylogeographic structure within C. variegatus . Analyses of mtDNA data recover six divergent clades throughout the range of C. variegatus . Topology of the mtDNA gene tree suggests separate origins of peninsular populations with an older lineage in the south and a younger one in the north. In contrast, analyses of multilocus nuclear data provide support for four lineages, corresponding to the subspecies C. v. abbotti , C. v. peninsularis , C. v. sonoriensis and C. v. variegatus . Phylogenetic analyses of the nuclear data recover C. v. abbotti and C. v. peninsularis as a clade, indicating a single origin of the peninsular populations. Discordance between the nuclear and mtDNA data is largely the result of repeated episodes of mtDNA introgression that have obscured both lineage boundaries and biogeographic history. Dating analyses of the combined nuclear and mtDNA data suggest that the peninsular clade diverged from the continental group in the Late Miocene.

Baja California↗