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At least 91 records · Page 5Linked to original sources
USGS1987

The geologic story of Yosemite National Park

Within 150 years, Yosemite has moved from great obscurity to worldwide fame as one of the most visited of our national parks. As a remarkable place where people can enjoy unparalleled scenes of natural beauty and where many easily observed geologic features are concentrated, the park is rivaled by few other areas on the planet. The majesty and immense variety of these features have inspired artists and photographers, intrigued tourists, and stirred controversy among geologists. Field studies in the Yosemite area have contributed to the development of our ideas about geologic processes, including the different actions of streams and glaciers in the evolution of the landscape, and the formation of granite, the basic bedrock of much of the Earth's continents. The park's role as a natural laboratory for geologic research cannot be overemphasized, and its investigation has led to many landmark studies by U.S. Geological Survey geologists over the past 70 years. In 1913, the first detailed program of research on the geology of the park and the origin ofYosemite Valley was begun by Francois Matthes and Frank Calkins. Their work, along with that of later generations of Survey geologists, myself included, serves as the basis for our present understanding of the geologic history of Yosemite and of the processes that formed and continue to mold its landscape. This book, which makes available in one volume a comprehensive summary of the current geologic knowledge of Yosemite National Park, is an excellent example of the Survey's continuing effort to provide earth-science information in the public service.

California↗
USGS2013

Correction 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, south into northwestern Baja California, Mexico. Through field reconnaissance and the study of preserved museum specimens we determined that the four reported populations of the arroyo toad from the Sonoran Desert region of Riverside, San Diego, and Imperial counties, California are in error. Two additional sites in the Sonoran Desert are discussed regarding the possibility that the arroyo toad occurs there. We recommend the continued scrutiny of arroyo toad records to maintain a high level of accuracy of its distribution and geographic extent.

California↗
USGS2015

Nelson's big horn sheep ( Ovis canadensis nelsoni ) trample Agassiz's desert tortoise ( Gopherus agassizii ) burrow at a California wind energy facility

Research on interactions between Agassiz's desert tortoises ( Gopherus agassizii ) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep ( Ovis aries ). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle ( Bos taurus ) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

Bulletin of the Southern California Academy of Sci↗
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↗
USGS2025

The Southwestern Pond Turtle (Actinemys pallida) in Baja California, Mexico: New localities and persistent threats

The Southwestern Pond Turtle ( Actinemys pallida ), the only native freshwater turtle in Baja California, is experiencing alarming population declines, echoing global patterns observed in freshwater turtles. We conducted comprehensive field surveys across the major drainages of northwestern Baja California to delineate the species' current distribution, identify critical threats to its persistence, and provide guidance for conservation actions. We documented the continued presence of A. pallida at 27 sites across 10 watersheds, ranging from sea level to 1,525 m in elevation. These include nine historically known sites and 18 newly recorded localities. The most pervasive threats we identified were habitat degradation, the proliferation of invasive aquatic species, and unsustainable water extraction. Despite these pressures, our findings confirm that A. pallida still occupies much of its historical range. However, urgent ecological research is needed to inform evidence-based strategies that ensure the long-term viability of this imperiled species.

Baja California↗
USGS2011

A previously unreported locality record for the Gila monster ( Heloderma suspectum )

Although the Gila Monster (Heloderma suspectum) is widely distributed throughout the Sonoran and portions of the Mojave Deserts of the southwestern United States and northwestern Mexico, details of its distribution in California are imperfectly known, due to the apparent rarity of the species in that state. In their review of Gila Monster records for California, Lovich and Beaman (2007) documented only 26 credible sightings during a period of 153 years. In May 2009 another sighting in California was documented by Ruppert (2010a, b) who photographed a specimen in the Providence Mountains, an area known for previous Gila Monster sightings (Lovich and Beaman 2007). In this paper we report the 28th credible record of a Gila Monster in California.

California↗
USGS1979

Osprey distribution, abundance, and status in western North America: III. The Baja California and Gulf of California population

An estimated 810 ± 55 pairs (minimum estimate) of ospreys ( Pandion haliaetus ) were nesting in the study area during our survey (24 March-1 April 1977). Approximately 174 pairs nested along the Pacific side of Baja California, 255 pairs along the gulf side, 187 pairs on the Midriff Islands, and 194 pairs in coastal Sonora and Sinaloa. Most nested on cliffs adjacent to the sea (59%); some nested on cactus in flat terrain (26%). Seven per cent nested on the ground, three percent nested in mangroves and other trees in the southern portion of the study area, and four percent nested on man-made structures. The extreme northwestern Baja California population that was extirpated early in this century has not recovered. However, several populations immediately to the south along the Pacific Coast now appear stationary. Pesticide residues in osprey eggs from Mexico were among the lowest reported for the species in North America.

Baja California↗
USGS2000

Evaluating temporal changes in stream condition in three New Jersey rive basins by using an index of biotic integrity

An index of biotic integrity (!B!) modified for New Jersey streams was used to compare changes in stream condition from the 1970s to the 1990s in Delaware, Passaic, and Raritan River Basins. Stream condition was assessed at 88 sampling locations. Mean IBI scores for all basins increased from the 1970s to the 1990s, but the stream-condition category improved (from fair to good) only for the Delaware River Basin. The number of benthic insectivores and the proportion of insectivorous cyprinds increased in all three basins; however, the number of white suckers decreased significantly only in the Delaware River Basin. Results of linear-regression analysis indicate a significant correlation between the percentage of altered land in the basin and change in IBI score (1970s to 1990s) for Delaware River sites. Results of analysis of variance of the rank-transformed IBI scores for the 1970s and 1990s indicate that the three basins was equal in the 1970s. Results of a multiple-comparison test demonstrated that the 1990s IBI values for the Delaware River Basin differed significantly from those for the Passaic and Raritan River Basins. Many factors, such as the imposition of the more stringent standards on water-water and industrial discharges during the 1980s and changes in land-use practices, likely contributed to the change in the Delaware River Basin. A general increase in IBI values for the Passaic, Raritan, and Delaware River Basins over the past 25 years appears to reflect overall improvements in water quality.

New Jersey↗