SEARCH · Geology Reports
Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
No abstract available.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
BACKGROUND Domestic cats (Felis catus) were first brought to Hawai`i aboard sailing ships of European explorers and colonists. The job of these predators was to control mice and rats on the ships during the long voyages. As in other places, cats were taken in and adopted by the families of Hawai`i and soon became household pets known as popoki. But cats have always been very well equipped to live and hunt on their own. On tropical archipelagos like the Hawaiian Islands where no other predatory mammals of comparable size existed, abundant and naive prey were particularly easy game, and cats soon thrived in the wild. Although the details of when cats first came to live in the wild remain little known, adventurers, writers, and naturalists of the day recorded some important observations. Feral cats were observed in remote wilderness around K?ilauea volcano on Hawai`i Island as early as 1840 by explorer William Brackenridge. Mark Twain was so impressed by the great abundance of cats when he visited Honolulu in 1866 that he reported his observations in the Sacramento Union newspaper, which were later reprinted in his book Roughing It: I saw... tame cats, wild cats, singed cats, individual cats, groups of cats, platoons of cats, companies of cats, regiments of cats, armies of cats, multitudes of cats, millions of cats...
Landscape patterns and processes reflect both natural ecosystem attributes and the policy and management decisions of individual Federal, State, county, and private organizations. Land-use regulation, water management, and habitat conservation and restoration efforts increasingly rely on landscape-level approaches that incorporate scientific information into the decision-making process. Since management actions are implemented to affect future conditions, decision-support models are necessary to forecast potential future conditions resulting from these decisions. Spatially explicit modeling approaches enable testing of different scenarios and help evaluate potential outcomes of management actions in conjunction with natural processes such as climate change. The ability to forecast the effects of changing land use and climate is critically important to land and resource managers since their work is inherently site specific, yet conservation strategies and practices are expressed at higher spatial and temporal scales that must be considered in the decisionmaking process.
Scientists at the U.S. Geological Survey (USGS) use a range of research approaches to investigate the genetics of native and non-native species that are being managed. This Fact Sheet outlines those approaches and explains the type of information they provide.
A deadly fungal pathogen, Batrachochytrium salamandrivorans ( Bsal ) that affects amphibian skin was discovered during a die-off of European fire salamanders ( Salamandra salamandra ) in 2014. This pathogen has the potential to worsen already severe worldwide amphibian declines. Bsal is a close relative to another fungal disease known as Batrachochytrium dendrobatidis ( Bd ). Many scientists consider Bd to be the greatest threat to amphibian biodiversity of any disease because it affects a large number of species and has the unusual ability to drive species and populations to extinction. Although not yet detected in the United States, the emergence of Bsal could threaten the salamander population, which is the most diverse in the world. The spread of Bsal likely will lead to more State and federally listed threatened or endangered amphibian species, and associated economic effects. Because of the concern expressed by resource management agencies, the U.S. Geological Survey (USGS) has made Bsal and similar pathogens a priority for research.
No abstract available.
This study was initiated to expand upon previous findings that indicated concentrations of dissolved solids, arsenic, boron, mercury, molybdenum, selenium, and uranium were either above geochemical background concentrations or were approaching or exceeding ecological criteria in the lower Humboldt River system. Data were collected from May 1998 to September 2000 to further characterize streamflow and surface-water and bottom-sediment quality in the lower Humboldt River, selected agricultural drains, Upper Humboldt Lake, and Lower Humboldt Drain (ephemeral outflow from Humboldt Sink). During this study, flow in the lower Humboldt River was either at or above average. Flows in Army and Toulon Drains generally were higher than reported in previous investigations. An unnamed agricultural drain contributed a small amount to the flow measured in Army Drain. In general, measured concentrations of sodium, chloride, dissolved solids, arsenic, boron, molybdenum, and uranium were higher in water from agricultural drains than in Humboldt River water during this study. Mercury concentrations in water samples collected during the study period typically were below the laboratory reporting level. However, low-level mercury analyses showed that samples collected in August 1999 from Army Drain had higher mercury concentrations than those collected from the river or Toulon Drain or the Lower Humboldt Drain. Ecological criteria and effect concentrations for sodium, chloride, dissolved solids, arsenic, boron, mercury, and molybdenum were exceeded in some water samples collected as part of this study. Although water samples from the agricultural drains typically contained higher concentrations of sodium, chloride, dissolved solids, arsenic, boron, and uranium, greater instantaneous loads of these constituents were carried in the river near Lovelock than in agricultural drains during periods of high flow or non-irrigation. During this study, the high flows in the lower Humboldt River produced the maximum instantaneous loads of sodium, chloride, dissolved solids, arsenic, boron, molybdenum, and uranium at all river-sampling sites, except molybdenum near Imlay. Nevada Division of Environmental Protection monitoring reports on mine-dewatering discharge for permitted releases of treated effluent to the surface waters of the Humboldt River and its tributaries were reviewed for reported discharges and trace-element concentrations from June 1998 to September 1999. These data were compared with similar information for the river near Imlay. In all bottom sediments collected for this study, arsenic concentrations exceeded the Canadian Freshwater Interim Sediment-Quality Guideline for the protection of aquatic life and probable-effect level (concentration). Sediments collected near Imlay, Rye Patch Reservoir, Lovelock, and from Toulon Drain and Army Drain were found to contain cadmium and chromium concentrations that exceeded Canadian criteria. Chromium concentrations in sediments collected from these sites also exceeded the consensus-based threshold-effect concentration. The Canadian criterion for sediment copper concentration was exceeded in sediments collected from the Humboldt River near Lovelock and from Toulon, Army, and the unnamed agricultural drains. Mercury in sediments collected near Imlay and from Toulon Drain in August 1999 exceeded the U.S. Department of the Interior sediment probable-effect level. Nickel concentrations in sediments collected during this study were above the consensus-based threshold-effect concentration. All other river and drain sediments had constituent concentrations below protective criteria and toxicity thresholds. In Upper Humboldt Lake, chloride, dissolved solids, arsenic, boron, molybdenum, and uranium concentrations in surface-water samples collected near the mouth of the Humboldt River generally were higher than in samples collected near the mouth of Army Drain. Ecological criteria or effect con
Explore the source record for details and available documents.
In the summer of 2007, we undertook an assessment of larval and juvenile sucker use of Hanks Marsh in Upper Klamath Lake, Oregon. This 1,200-acre marsh on the southeastern shoreline of the lake represents part of the last remaining natural emergent wetland habitat in the lake. Because of the suspected importance of this type of habitat to larval and juvenile endangered Lost River and shortnose suckers, it was thought that sucker abundance in the marsh might be comparatively greater than in other non-vegetated areas of the lake. It also was hoped that Hanks Marsh would serve as a reference site for wetland restoration projects occurring in other areas of the lake. Our study had four objectives: to (1) examine seasonal distribution and relative abundance of larval suckers in and adjacent to Hanks Marsh in relation to habitat features such as depth, vegetation, water quality, and relative abundance of non-sucker species; (2) determine the presence or absence and describe the distribution of juvenile suckers [35 to 80 mm standard length (SL)] along the periphery of Hanks Marsh; (3) assess spatial and temporal overlap between larval suckers and their potential predators; and (4) assess suitability of water quality throughout the summer for young-of-the-year suckers. Due to the low number of suckers found in the marsh and our inability to thoroughly sample all marsh habitats due to declining lake levels during the summer, we were unable to completely address these objectives in this pilot study. The results, however, do give some indication of the relative use of Hanks Marsh by sucker and non-sucker species. Through sampling of larval and juvenile suckers in various habitat types within the marsh, we determined that sucker use of Hanks Marsh may be very low in comparison with other areas of the lake. We caught only 42 larval and 19 juvenile suckers during 12 weeks of sampling throughout the marsh. Sucker catches were rare in Hanks Marsh, and were lower than catch rates in other marshes of Upper Klamath Lake and in other nearshore and offshore areas of the lake. Based on the few suckers we did capture in Hanks Marsh, larvae tended to be found more often in vegetated habitats. A modified sampling design and approach may be necessary to address the objectives in this study, given that declining lake-surface elevation prevented us from adequately sampling all portions of the marsh throughout the sampling season. Common non-sucker species in Hanks Marsh included juvenile and adult brown bullhead, larval blue chub, tui chub, fathead minnow, and yellow perch. This species composition was similar to that of other marshes in Upper Klamath Lake but most species were found in lower numbers in Hanks Marsh than other marshes. It may be that use of Hanks Marsh is limited by poor water quality, which we found to exist at many sites after June. It also may be that access to or habitat in the marsh is limited at certain times of the year by low water. Although the results from this initial study of Hanks Marsh indicate that the area may have little direct benefit for sucker species, indirect benefits for these species possibly may come from its positive influence on some aspects of water quality in the lake, such as regulation of pH. It also may be the case that use of Hanks Marsh may vary by year and conditions; however, under the current scope of the study, we were unable to investigate inter-annual variability.