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G. M. Fellers

Publications and source records attributed to G. M. Fellers.

11 recordsLinked to original sources
USGS2010

Rangewide phylogeography and landscape genetics of the Western U.S. endemic frog Rana boylii (Ranidae): Implications for the conservation of frogs and rivers

Genetic data are increasingly being used in conservation planning for declining species. We sampled both the ecological and distributional limits of the foothill yellow-legged frog, Rana boylii to characterize mitochondrial DNA (mtDNA) variation in this declining, riverine amphibian. We evaluated 1525 base pairs (bp) of cytochrome b and ND2 fragments for 77 individuals from 34 localities using phylogenetic and population genetic analyses. We constructed gene trees using maximum likelihood and Bayesian inference, and quantified genetic variance (using AMOVA and partial Mantel tests) within and among hydrologic regions and river basins. Several moderately supported, geographically-cohesive mtDNA clades were recovered for R. boylii. While genetic variation was low among populations in the largest, most inclusive clade, samples from localities at the edges of the geographic range demonstrated substantial genetic divergence from each other and from more central populations. Hydrologic regions and river basins, which represent likely dispersal corridors for R. boylii, accounted for significant levels of genetic variation. These results suggest that both rivers and larger hydrologic and geographic regions should be used in conservation planning for R. boylii. ?? 2010 US Government.

Conservation Genetics↗
USGS2009

Toxicity of two insecticides to California, USA, anurans and its relevance to declining amphibian populations

Contaminants have been associated with population declines of several amphibian species in California (USA). Pesticides from the Central Valley of California are transported by winds into the Sierra Nevada Mountains and precipitate into wet meadows where amphibians breed. The present study examined the chronic toxicity of two of the insecticides most commonly used in the Central Valley and found in the mountains, chlorpyrifos and endosulfan, to larval Pacific treefrogs (Pseudacris regilla) and foothill yellow-legged frogs (Rana boylii) and discusses the implications of this toxicity to declining amphibian populations. Larvae were exposed to the pesticides from Gosner stages 25 to 26 through metamorphosis. The estimated median lethal concentration (LC50) for chlorpyrifos was 365 ??g/L in P. regilla and 66.5 ??g/L for R. boylii. Time to metamorphosis increased with concentration of chlorpyrifos in both species, and cholinesterase activity declined with exposure concentration in metamorphs of both species at Gosner stages 42 to 46. For endosulfan, the estimated LC50 was 15.6 ??g/L for P. regilla and 0.55 ??g/L for R. boylii. All R. boylii exposed to concentrations of greater than 0.8 ??g/L died before they entered metamorphosis. Pseudacris regilla remains relatively abundant and is broadly distributed throughout California. In contrast, R. boylii is among the species experiencing severe population declines. The present study adds to the increasing evidence that pesticides are very harmful to amphibians living in areas that are miles from sources of pesticide application. ?? 2009 SETAC.

Environmental Toxicology and Chemistry↗
USGS2008

Turning population trend monitoring into active conservation: Can we save the cascades frog (Rang cascadae) in the Lassen Region of California?

Monitoring the distribution, population size, and trends of declining species is necessary to evaluate their vulnerability to extinction. It is the responsibility of scientists to alert management professionals of the need for preemptive action if a species approaches imminent, regional extirpation. This is the case with Rana cascadae (Cascades Frog) populations near Lassen Peak From 1993 to 2007, we conducted 1,873 amphibian surveys at 856 sites within Lassen Volcanic National Park and Lassen National Forest, California, USA. These surveys encompassed all R. cascadae habitats: ponds, lakes, meadows, and streams on those lands. We found frogs at only six sites during 14 years of surveys, and obtained one report of a single frog at one additional locality. These sites represented < 1% of the historically suitable habitat within the Lassen region. The number of R. cascadae in the Lassen area has declined since 1991, and one population is now extirpated. We found no evidence of reproduction in most of the populations, and reproduction at all but one of the other sites remained lower than the annual reproductive output of one breeding pair for > 12 years. Causes for the decline remain unclear, but introduced trout, disease, and pesticides are likely factors. We recommend that (1) additional protection for R. cascadae within 50 km of Lassen Peak; (2) investigation of the genetics of R. cascadae in California; (3) research into the role of possible causative factors in these declines; and (4) implementation of a feasibility study to captive breed and reintroduce R. cascadae in the Lassen area. Copyright ?? 2008. Gary Fellers. All rights reserved.

Herpetological Conservation and Biology↗
USGS2007

Abundance and impacts of fallow deer leks at Point Reyes National Seashore

Fallow deer, Dama dama, were released at Point Reyes National Seashore in the 1940s. A population of about 860 of these non-native deer are now well-established within the park. Fallow deer have an unusual mating system. During the fall, males establish areas known as leks where they display to potential mates. A fallow deerlek is typically an area of 100-150 m2 and usually includes 2-5 males. Using their hooves and antlers, each male clears away most or all of the vegetation and digs a rutting pit that he defends throughout the breeding season. A total of 159 fallow deer leks was located within the 298.8 ha of our study areas. In the Olema Valley, where fallow deer densities are high, there were 116 leks, compared with 43 in the similar sized Estero trailhead study area, where deer density was moderate. A total of 705 rutting pits was found in the two study areas, with a mean of 5.1 pits per lek in the Olema Valley and 2.5 for Estero trailhead. The leks and associated pits have resulted in damage to both the ground and the associated vegetation, especially in riparian areas.

California Fish and Game↗
USGS2006

Temporal organization of an anuran acoustic community in a Taiwanese subtropical forest

We recorded anuran vocalizations in each of four habitats at Lien Hua Chih Field Station, Taiwan, between July 2000 and July 2001. For each 27 biweekly sample, eight recorders taped calls for 1 min out of every 11 between the hours of 17:00 and 07:00. We obtained 11 481 recordings with calls, and identified 21 503 frogs or groups of frogs. These included 20 species, with an average of 10.4??3.5 species calling each night. Some species called year round, others called in the spring and summer, and a third group called only in the fall and winter. The number of species calling and the maximum calling intensity were correlated with both rainfall and air temperature. The nightly pattern of calling varied among species. Most species called continuously throughout the night, whereas some had a peak right after dusk. A few species had different nightly calling patterns in different habitats. Both Rana limnocharis and Rana kuhlii changed their calling pattern in the presence of large choruses of other anuran species. ?? 2006 The Authors.

Journal of Zoology↗
USGS2004

Pesticides in mountain yellow-legged frogs (Rana muscosa) from the Sierra Nevada Mountains of California, USA

In 1997, pesticide concentrations were measured in mountain yellow-legged frogs (Rana muscosa) from two areas in the Sierra Nevada Mountains of California, USA. One area (Sixty Lakes Basin, Kings Canyon National Park) had large, apparently healthy populations of frogs. A second area (Tablelands, Sequoia National Park) once had large populations, but the species had been extirpated from this area by the early 1980s. The Tablelands is exposed directly to prevailing winds from agricultural regions to the west. When an experimental reintroduction of R. muscosa in 1994 to 1995 was deemed unsuccessful in 1997, the last 20 (reintroduced) frogs that could be found were collected from the Tablelands, and pesticide concentrations in both frog tissue and the water were measured at both the Tablelands and at reference sites at Sixty Lakes. In frog tissues, dichlorodiphenyldichloroethylene (DDE) concentration was one to two orders of magnitude higher than the other organochlorines (46 ?? 20 ng/g wet wt at Tablelands and 17 ?? 8 Sixty Lakes). Both ??-chlordane and trans-nonachlor were found in significantly greater concentrations in Tablelands frog tissues compared with Sixty Lakes. Organophosphate insecticides, chlorpyrifos, and diazinon were observed primarily in surface water with higher concentrations at the Tablelands sites. No contaminants were significantly higher in our Sixty Lakes samples.

Environmental Toxicology and Chemistry↗
USGS2001

Oral chytridiomycosis in the mountain yellow-legged frog (Rana muscosa)

The chytrid fungus Batrachochytrium dendrobatidis was originally reported in wild frog populations in Panama and Australia, and from captive frogs in the U.S. National Zoological Park (Washington, DC). This recently described fungus affects the keratinized epidermis of amphibians and has been implicated as a causative factor in the declines of frog populations. We report here the presence of B. dendrobatidis in larval and recently metamorphosed mountain yellow-legged frogs ( Rana muscosa ) in or near the Sierra Nevada Mountains of California, an area where declines have been documented in all five species of native anurans. Forty-one percent (158 of 387) of larval R. muscosa examined in the field with a hand lens and 18% (14 of 79) of preserved larvae had abnormalities of the oral disc. Twenty-eight larvae were collected from 10 sites where tadpoles had been observed with missing or abnormally keratinized mouthparts, and 24 of these were examined for infection. Sixty-seven percent (16 of 24) of these tadpoles were infected with B. dendrobatidis. Batrachochytrium dendrobatidis was cultured from both tadpoles and recent metamorphs from one of these sites. Tadpoles with mouthpart abnormalities or confirmed chytrid fungus infections were collected at 23 sites spanning a distance of > 440 km and an elevational range from 1658-3550 m. Life-history traits of R. muscosa may make this species particularly susceptible to infection by Batrachochytrium . We recommend that biologists examine tadpoles for oral disc abnormalities as a preliminary indication of chytridiomycosis. Further, we believe that biologists should take precautions to prevent spreading this and other amphibian diseases from one site to another.

California↗