SEARCH · Geology Reports

Results for “Waterfowl”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources

USGS1997

Global change and submerged aquatic vegetation research

Communities of submerged aquatic vegetation (SAY) are important components of many freshwater, brackish, and marine aquatic ecosystems. They prevent erosion by baffling the impacts of waves, especially from storms. These aquatic plant communities remove nutrients and other pollutants from river and runoff inputs to coastal areas, preventing their entry into surrounding waters. They provide nursery habitat for fish, shrimp, and other species, as well as forage for wintering waterfowl and endangered species such as sea turtles and manatees. Unfortunately, not only have the distribution and abundance of seagrasses in the northern Gulf of Mexico declined precipitously during the past 50 years, most notably from widespread deterioration of water quality, but submerged aquatic plant communities are also susceptible to long-term environmental changes that are predicted to accompany global climate change.

Fact Sheet↗

USGS2002

Modeling the bathymetry of Catahoula Lake: Specialized technology for wetland management

Catahoula Lake is the largest natural freshwater lake in Louisiana, covering more than 46 square miles (120 km2) (fig. 1). The lake is a principal stopover and wintering site for hundreds of thousands of migratory waterfowl and shorebirds. Scientists from the USGS National Wetlands Research Center are applying some of the research facility's specialties?wetland plant research, aerial and ground surveys, digital mapping, and computer modeling?to facilitate wetland management at Catahoula Lake.

Fact Sheet↗

USGS2005

Translocation of Endangered Laysan Ducks to Midway Atoll National Wildlife Refuge (2004-5)

BACKGROUND Island ecosystems throughout the Pacific have undergone catastrophic species loss, largely due to the effects of alien or non-native species. Rats, in particular, pose significant threats to native species. In Hawai`i, the appearance of rats (which are not native to Hawai`i) in the subfossil record coincides with the disappearance of ground nesting birds. Sadly, only three of Hawai`i?s 10 endemic waterfowl species still exist today. The Laysan Duck (Anas laysanensis), also known as the Laysan Teal, is a critically endangered dabbling duck that is restricted to a single population on the remote and rat-free Laysan Island (Fig. 1). The Laysan Duck was listed as an endangered species in 1966 because of its small population, limited distribution, and dependence on a fragile island ecosystem. The same threats identified in 1966 continue to plague the species today.

Fact Sheet↗

USGS2007

Hawaiian Duck's Future Threatened by Feral Mallards

Nearly 70 percent of Hawaii's native bird species are found nowhere else on Earth, and many of these species are declining or in danger of extinction. Although the Hawaiian Islands were once home to a remarkable diversity of waterfowl, only three species remain-the Hawaiian Goose (Nene), Laysan Duck, and Hawaiian Duck (Koloa maoli)-all Federally endangered. The Koloa maoli is the only Hawaiian bird threatened by 'genetic extinction' from hybridization with an invasive species-feral Mallard ducks. U.S. Geological Survey (USGS) biologists in Hawaii are working to find the causes of bird endangerment and ways to prevent extinction of the Koloa maoli and other threatened birds.

Fact Sheet↗

USGS2009

Northern Prairie Wildlife Research Center

The Northern Prairie Wildlife Research Center (NPWRC) conducts integrated research to fulfill the Department of the Interior's responsibilities to the Nation's natural resources. Located on 600 acres along the James River Valley near Jamestown, North Dakota, the NPWRC develops and disseminates scientific information needed to understand, conserve, and wisely manage the Nation's biological resources. Research emphasis is primarily on midcontinental plant and animal species and ecosystems of the United States. During the center's 40-year history, its scientists have earned an international reputation for leadership and expertise on the biology of waterfowl and grassland birds, wetland ecology and classification, mammalian behavior and ecology, grassland ecosystems, and application of statistics and geographic information systems. To address current science challenges, NPWRC scientists collaborate with researchers from other U.S. Geological Survey centers and disciplines (Biology, Geography, Geology, and Water) and with biologists and managers in the Department of the Interior (DOI), other Federal agencies, State agencies, universities, and nongovernmental organizations. Expanding upon its scientific expertise and leadership, the NPWRC is moving in new directions, including invasive plant species, restoration of native habitats, carbon sequestration and marketing, and ungulate management on DOI lands.

Fact Sheet↗

USGS2011

A promising tool for subsurface permafrost mapping-An application of airborne geophysics from the Yukon River Basin, Alaska

Permafrost is a predominant physical feature of the Earth's Arctic and Subarctic clines and a major consideration encompassing ecosystem structure to infrastructure engineering and placement. Perennially frozen ground is estimated to cover about 85 percent of the state of Alaska where northern reaches are underlain with continuous permafrost and parts of interior Alaska are underlain by areas of discontinuous and (or) sporadic permafrost (fig. 1). The region of Interior Alaska, where permafrost is scattered among unfrozen ground, is a complex mosaic of terrains and habitats. Such diversity creates arrays of lakes and surface-water and groundwater patterns that continental populations of migratory waterfowl and internationally significant fisheries have adapted to over time. A road or pipeline might pass over frozen and unfrozen ground, affecting the types of materials and engineering approaches needed to sustain the infrastructure. Effective mapping of discontinuous permafrost at scales meaningful ecologically and (or) from an engineering perspective has been a long-standing challenge. Using techniques such as borehole logging for site-specific assessments or botanical techniques that can suggest underlying permafrost distributions can be labor intensive and difficult to accomplish at the scale and remoteness of much of Alaska. The climate is changing in the Arctic and Subarctic regions. The warming observed throughout much of Alaska could create widespread changes in permafrost. How the warming of the permafrost affects near-surface processes, ecosystems, and community infrastructure and ecosystems is not clear. A better understanding of the dynamic distribution and physical properties of permafrost, from continuous to discontinuous, will provide knowledge of how the permafrost environment may change in the future and help inform engineering and natural resource response strategies. Here we discuss an application of an airborne remote sensing methodology for mapping and shade imaging permafrost characteristics at various scales. This work provides the first look into three-dimensional distribution of permafrost in the areas around Fort Yukon and is a demonstration of the application of airborne electromagnetic (AEM) to permafrost mapping. Such an approach is attractive, particularly in Arctic and Subarctic studies, where ground access is difficult and ecosystems are fragile. In June 2010, the U.S. Geological Survey (USGS) conducted an AEM survey near Fort Yukon, Alaska. The primary focus of this survey was to map the distribution of permafrost in selected areas in order to supply information for the development of groundwater models of the Yukon River Basin. However, the methodologies have more far-reaching ecological and engineering applications. Approximately 1,800 line kilometers were acquired in a combination of typical block style surveying in the immediate area of Fort Yukon and in long reconnaissance lines over a broader area. The widely spaced lines were flown to cross the modern Yukon River in "X" like patterns with intersections at features that have been previously studied (fig. 2). AEM is used to gather data on the electrical resistivity of materials in the subsurface below the flight path of the helicopter, which are then analyzed to interpret the subsurface lithology and the location and extent of permafrost. For this survey, the electrical resistivity was imaged to depths on the order of 50-100 meters. Images from the survey can be qualitatively compared with known permafrost features and suggest new permafrost features. Electrical properties of earth materials are affected by lithology as well as temperature and the presence of ice; frozen materials become substantially more resistive. This allows for the identification of permafrost from the resistivity image (Abraham and others, 2011). In the area of Fort Yukon, the AEM survey shows elevated resistivities extending to depth, likely indicative of thick permafrost. This depth corresponds well to observations from a borehole drilled in the area in the late 1990s, which detected permafrost to a depth of about 100 meters (Clark and others, 2009). In contrast to the area of Fort Yukon, the Yukon River and its floodplain are not associated with deep resistive sediments, suggesting a lack of deep permafrost, at least within the depth range of the AEM mapping (fig. 3).

Yukon River Basin↗

USGS2021

USGS Chesapeake Science Strategy 2021-2025

The Chesapeake Bay ecosystem is a national treasure that provides almost $100 billion annually of goods and services. The Chesapeake Bay Program (CBP), is one of the largest federal-state restoration partnerships in the United States and is underpinned by rigorous science. The U.S. Geological Survey (USGS) has a pivotal role as a science provider for assessing ecosystem condition and response in the Chesapeake watershed. Despite significant CBP accomplishments, the pressures of climate change and competing demands on land use and change require an acceleration of progress towards the 10 goals in the Chesapeake Bay Watershed Agreement. USGS Chesapeake studies are increasing efforts to provide integrated science and are engaging stakeholders to inform the multi-faceted restoration and conservation decisions to improve habitat for fish and waterfowl, and socio-economic benefits to the 18 million people living in the watershed.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2022

North Dakota and Landsat

The State of North Dakota once did not figure prominently in the Nation’s economy. The sparsely populated State supported food production, and hunters and anglers were drawn to its lakes, rivers, and wide-open spaces, but its economy was overshadowed by that of other States. However, the State and its prairie expanses recently rocketed from an economic afterthought to a national energy leader with the soaring production of oil and natural gas in the Bakken oil patch. The Bakken development has been transformative for North Dakota’s landscapes in myriad ways. It has boosted economic output, drawn thousands of new residents to cities like Williston and Watford City, and led to a proliferation of oil and gas pads. In the past two decades, North Dakota experienced other major changes, such as the expansion of the depressional wetlands of the Prairie Pothole Region on the eastern side of the State. These critical breeding areas for waterfowl, which stretch across Minnesota, South Dakota, North Dakota, and Canada, are home to more than 50 percent of North America’s migratory birds. Changes from oil and gas production, urban development, and wetland resurgence can all be tracked over time using the unparalleled Earth observation record of the U.S. Geological Survey Landsat data archive. Its 50-year record of repeat imagery also aids in the monitoring, cataloging, and management of cropland, invasive insect species, and natural or human-made disaster recovery. Here are just a few examples of the benefits offered to North Dakota by the Landsat Program.

North Dakota↗

USGS1967

Water resources of the Roseau River Watershed, Northwestern Minnesota

The drainage area of the Roseau River consists of 2,060 square miles above its confluence with the Red River of the North. About 1,150 square miles lie in the United States and 910 square miles in Canada. This report deals only with that portion within the United States, except for a detailed analysis of low flow characteristics of tributary streams. Most of the area is within Roseau County, but small portions are in Marshall, Beltrami, Lake of the Woods, and Kittson Counties. Most of the watershed has little relief, and lies entirely within the plain of former Glacial Lake Agassiz. However, the flat topography of this lake washed till plain is broken by beach ridges in its southwestern part and Beltrami Island, a topographic high underlain by sand, in tis southeastern part. Population within the watershed is about 8000. The town of Roseau, the largest community, has a population of 2146 (1960). The watershed has an agricultural economy. Spring wheat, oats, and bluegrass seed are the three most important crops in the area, but many other small grains, legumes, and grasses are also grown. Dairy farming and sheep raising are the most important types of livestock production and for many farms stock is the major sources of income. Large areas of the watershed are peat lands, covered with shrubs, marsh grasslands, and spruce, tamarack, and cedar trees. Forest vegetation in the remainder of the area is largely aspen, but oak is common on the beach ridges and jack pine is common on Beltrami Island. Outdoor recreation in the area is primarily hunting of deer, small game, and waterfowl. This report is a general appraisal of the water resources in the Roseau River watershed unit. Detailed studies of water movement through the ground-water reservoir are needed for more exact determination of the amount of water immediately available and the specific effects of water-management practices.

Minnesota↗

USGS1968

Water resources of the Mustinka and Bois de Sioux Rivers watershed, west-central Minnesota

The Mustinka and Bois de Sioux Rivers watershed is mantled by till deposits with scattered sand deposits. The west-central and northwestern part of the watershed was covered by Glacial Lake Agassiz and the resulting land surface is a flat, lake-washed till plain. Patches and ridges of sand scattered throughout the lake plain were formed as beach ridges and offshore bars. Small, isolated areas of lake clay also occur within this area. The remainder of the watershed is glacial moraine characterized by rolling topography in all but the extreme eastern edge which has more local relief and more permanent lakes. Alluvial sand deposits are found in the eastern part of the morainal area. The drainage area of the watershed in Minnesota is 1,429 square miles. The area includes mors of Traverse County and parts of Big Stone, Stevens, Grant, Ottertail, and Wilkin Counties. Population within the watershed unit is about 20,000. The largest community, Wheaton, has a population of 2,102. The agricultural economy of the area is concentrated on grain farming, although some dairying is carried on. The principal grain crops are corn and oats. Flax, soybeans, and barley are also very commonly grown. The natural vegetation in the area was largely prairie. A hardwood deciduous forest grew only on the extreme eastern edge. Today, the area is almost entirely farm land containing numerous local woodlots. Outdoor recreation is concentrated on waterfowl and pheasant hunting. Fishing is done in Lake Traverse and in the larger lakes in the eastern part of the morainal area.

Minnesota↗

USGS2002

Hydrologic, sediment, and biological data associated with irrigation drainage in the middle Green River basin, Utah and Colorado, water years 1991-2000

Hydrologic, sediment, and biological data were collected in the middle Green River basin in eastern Utah from 1991 to 2000 in an effort to monitor the effects of irrigation drainage on wetland areas and streams, aid in the development of remediation plans, and evaluate the effectiveness of selenium remediation efforts at Stewart Lake Waterfowl Management Area (WMA). Data consist primarily of selenium concentrations in surface water, ground water, bottom sediment, and biological samples. Supporting hydrologic data include field measurements of temperature, pH, specific conductance, water levels in wells, and discharge at surface-water sites. Selected water samples also were analyzed for major ions, trace elements, nutrients, and gross alpha and beta radiation. The concentration of selected selenium species is reported for several bottom-sediment samples from Stewart Lake WMA and the concentration of total selenium in suspended-sediment samples from the area are included. Well logs for six wells installed at Stewart Lake WMA are presented along with trace-element data for several biological samples collected at selected sites throughout the middle Green River basin.

Colorado, Utah, Wyoming↗

USGS2005

Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies. Special interest groups and local residents often criticize a change in Refuge management, especially if there is a perceived negative impact to the local economy. Having objective data on income and employment impacts may show that these economic fears are drastically overstated. Quite often, residents do not realize the extent of economic benefits a Refuge provides to a local community; yet at the same time overestimate the impact of negative changes. Spending associated with Refuge recreational activities such as wildlife viewing and hunting can generate considerable tourism activity for the regional economy. Refuge personnel typically spend considerable amounts of money purchasing supplies in the local lumber and hardware stores, repairing equipment and purchasing fuel at the local service stations, as well as reside and spend their salaries in the community. The purpose of this study was to provide the economic analysis needed for the Sand Lake NWR CCP by evaluating the regional economic impacts associated with the Sand Lake NWR Draft CCP management strategies. For Refuge CCP planning, an economic impact analysis describes how current (No Action Alternative) and proposed management activities (alternatives) affect the local economy. This type of analysis provides two critical pieces of information: (1) it illustrates a refuge’s contribution to the local community; and (2) it can help in determining whether local economic effects are or are not a real concern in choosing among management alternatives. Sand Lake NWR is currently managed to improve and maintain habitat for nesting and resting waterfowl and other migratory birds, such as diving and puddle ducks, geese, grebes, herons, egrets, gulls, and terns. There are three alternatives evaluated in the draft CCP. Alternative 1, the No Action alternative, would continue Refuge management at current levels and would not involve extensive restoration of cropland, grassland, and wetland habitat or improvements to roads, interpretive, and administrative facilities. No new funding or staff levels would occur and programs would follow the same direction, emphasis, and intensity as they do at present. Alternative 2 would maximize the biological potential of the refuge for species of grassland-nesting birds. This would be accomplished through intense management of upland habitat for nesting migratory birds, minimal management for resident species, and minimization of public use that may interfere with migratory bird production. The third alternative takes an integrated approach, with management practices that would serve to maximize the biological potential of Sand Lake for migratory birds. This report first provides a description of the local community and economy near the Refuge. An analysis of current and proposed management strategies that could affect the local economy is then presented. The Refuge management activities of economic concern in this analysis are Refuge personnel staffing and Refuge spending within the local community, and spending in the local community by Refuge visitors.

Sand Lake National Wildlife Refuge↗

USGS2005

Submersed Aquatic Vegetation Modeling Output Online

Introduction The ability to predict the distribution of submersed aquatic vegetation in the Upper Mississippi River on the basis of physical or chemical variables is useful to resource managers. Wildlife managers have a keen interest in advanced estimates of food quantity such as American wildcelery (Vallisneria americana) population status to give out more informed advisories to hunters before the fall hunting season. Predictions for distribution of submerged aquatic vegetation beds can potentially increase hunter observance of voluntary avoidance zones where foraging birds are left alone to feed undisturbed. In years when submersed aquatic vegetation is predicted to be scarce in important wildlife habitats, managers can get the message out to hunters well before the hunting season (Jim Nissen, Upper Mississippi River National Wildlife and Fish Refuge, La Crosse District Manager, La Crosse, Wisconsin, personal communication). We developed a statistical model to predict the probability of occurrence of submersed aquatic vegetation in Pool 8 of the Upper Mississippi River on the basis of a few hydrological, physical, and geomorphic variables. Our model takes into consideration flow velocity, wind fetch, bathymetry, growing-season daily water level, and light extinction coefficient in the river (fig. 1) and calculates the probability of submersed aquatic vegetation existence in Pool 8 in individual 5- x 5-m grid cells. The model was calibrated using the data collected in 1998 (516 sites), 1999 (595 sites), and 2000 (649 sites) using a stratified random sampling protocol (Yin and others, 2000b). To validate the model, we chose the data from the Long Term Resource Monitoring Program (LTRMP) transect sampling in backwater areas (Rogers and Owens 1995; Yin and others, 2000a) and ran the model for each 5- x 5-m grid cell in every growing season from 1991 to 2001. We tallied all the cells and came up with an annual average percent frequency of submersed aquatic vegetation occurrence and compared the results with actual LTRMP survey data (fig. 2). Both a paired Student's test (P = 0.4620) and a Wilcoxon's two-sample test (P = 0.4738) did not contradict our null hypothesis that the model prediction and the sampling data are statistically the same. We have not found an effective statistical test to compare model-predicted spatial pattern with aerial photography geographic information, but we are satisfied with the model's outcome on the basis of visual inspection (fig. 3). A unique feature about this model is that a prediction can be made by the end of June each year; therefore, providing wildlife managers an assessment of current year vegetation growth condition 3 to 4 months ahead of the arrival of migrating waterfowl that feed on submersed aquatic vegetation. We are working with the LTRMP partnership to create a mechanism so that model predictions (fig. 4) can be updated annually and the results posted on the LTRMP Web site. Our model underestimated the prevalence of vegetation from 2001 to 2004. We speculate that the summer water level reduction conducted in 2001 and 2002 triggered vegetation responses that are outside the model's domain. Future enhancement of the model will incorporate the summer water level drawdown effects as well as the effects of growth conditions in previous years.

Open-File Report↗

USGS2005

Graphical user interface for accessing water-quality data for the Devils Lake basin, North Dakota

Maintaining the quality of surface waters in the Devils Lake Basin in North Dakota is important for protecting the agricultural resources, fisheries, waterfowl and wildlife habitat, and recreational value of the basin. The U.S. Geological Survey, in cooperation with local, State, and Federal agencies, has collected and analyzed water-quality samples from streams and lakes in the basin since 1957, and the North Dakota Department of Health has collected and analyzed water-quality samples from lakes in the basin since 2001. Because water-quality data for the basin are important for numerous reasons, a graphical user interface was developed to access, view, and download the historical data for the basin. The interface is a web-based application that is available to the public and includes data through water year 2003. The interface will be updated periodically to include data for subsequent years.

Open-File Report↗

USGS2006

Wildlife and habitat damage assessment from Hurricane Charley: Recommendations for recovery of the J. N. "Ding" Darling National Wildlife Refuge Complex

• On 13 August 2004, the first of four hurricanes to strike Florida in <6 weeks came ashore near J. N. “Ding” Darling National Wildlife Refuge (JNDDNWR) Complex, Sanibel Island, Florida. The eye of Category 4 Hurricane Charley passed just north of Sanibel Island with maximum sustained winds of 145 mph (123 knots) and a storm surge of 0.3-2.7 m (1-9 ft). Three USGS-BRD scientists (coastal ecologist and research wildlife biologists) and a USFWS wildlife biologist surveyed the storm damage to JNDDNWR Complex on the ground from 20-24 September 2004. • At the request of United States Fish and Wildlife Service refuge staff, the USGS team concentrated on assessing damage to wetlands and habitat for selected bird populations (especially mangrove forests, Mangrove Cuckoos [Coccyzus minor], and Black-whiskered Vireo [Vireo altiloquus]), waterbird rookeries (mangrove islands), impoundments (waterbirds and waterfowl), sea grass beds (manatees), and upland hardwood hammocks and ridges (threatened eastern indigo snake [Drymarchon couperi]). • The refuge complex sustained moderate to catastrophic damage to vegetation, especially mangrove forests and waterbird nesting or roosting islands. Lumpkin Island, Hemp Island, and Bird Key waterbird nesting areas had >50% and sometimes 90% of their vegetation severely damaged (dead, broken tree stems, and tipped trees). The Shell Mound Trail area of JNDDNWR sustained catastrophic damage to its old growth mangrove forests. Direct storm mortality and injury to manatees in the area of the JNDDNWR Complex was probably slight as manatees may have several strategies to reduce storm mortality. Damage to seagrass beds, an important habitat for manatees, fishes and invertebrates, is believed to be limited to the breach at North Captiva Island. At this breach, refuge staff documented inundation of beds by sand and scarring by trees dragged by winds. • Because seagrass beads and manatee habitat extend beyond refuge boundaries (see p. 28), a regional approach with partner agencies to more thoroughly assess storm impacts and monitor recovery of seagrass and manatees is recommended. • Besides intensive monitoring of waterbirds and their nesting habitat (pre- and post-storm), the survey team recommends that the Mangrove Cuckoo be used as an indicator species for recovery of mangrove forests and also for monitoring songbirds at risk (this songbird is habitat-area sensitive). Black-whiskered Vireo may be another potential indicator species to monitor in mangrove forests. Monitoring for these species can be done by distance sampling on transects or by species presenceabsence from point counts. • Damaged vegetation should be monitored for recovery (permanent or long-term plots), especially where previous study plots have been established and with additional plots in mangrove forests of waterbird nesting islands and freshwater wetlands. • Potential loss of wetlands (and information for management) may be prevented by water level monitoring (3 permanent stations), locating the positions (GPS-GIS) and maintaining existing water control structures, creating a GIS map of the refuge with accurate vertical data, and monitoring and eradicating invasive plants. Invasive species, including Brazilian pepper (Schinus terebinthifolius) and air potato (Dioscorea bulbifora), were common in a very limited survey and may become more dominant in areas damaged by the storm. Special attention is needed to eradicate these exotic plants. • As an important monitoring goal, the survey team recommends that species presence-absence data analysis (with probability of detection) be used to determine changes in animal communities. This could be accomplished possibly with comparison to other storm-damaged and undamaged refuges in the Region. This information may be helpful to refuge managers when storms return in the future.

Florida↗

USGS2009

Results From a Microbial Source-Tracking Study at Villa Angela Beach, Cleveland, Ohio, 2007

During the 2007 recreational season at Villa Angela Beach in Cleveland, Ohio, scientists with the U.S. Geological Survey (USGS) and the Northeast Ohio Regional Sewer District (NEORSD) found high Escherichia coli (E. coli) concentrations that were not easily explained by results obtained to date in ongoing investigations of recreational water quality at the beach. To help understand the sources behind these elevated E. coli concentrations, the USGS and NEORSD sampled beach-area water for Bacteroides DNA markers. Bacteroides are a group of enteric bacteria that are being used in microbial source tracking, in hope that host-associated DNA markers could be used to indicate potential sources of E. coli in the Villa Angela environment. The USGS Ohio Water Microbiology Laboratory analyzed a total of 13 source samples (sewage and waterfowl feces) and 33 beach-area water and sand samples for three Bacteroides DNA markers. This report lists the results of those analyses, along with environmental conditions at Villa Angela on the dates that samples were collected.

Open-File Report↗

USGS2010

Distribution of the non-native gastropod Melanoides tuberculatus in Biscayne National Park, Florida

Introduction Melanoides tuberculatus (fig. 1), a gastropod that is not native to South Florida, was identified in Biscayne National Park (BNP) while researchers from the U.S. Geological Survey were conducting other studies around the Black Point canals in the summer of 2003. A study to determine the distribution, genetics, and salinity tolerance of this freshwater species began in 2004. For park managers and the recreational users of BNP, the presence of Melanoides tuberculatus is cause for concern because it is the intermediate host for several trematode parasites that affect humans and animals in multiple ways: Human health concerns include parasites (trematode worms) that affect the lung (Paragonimus westermani) and the liver ( Clonorchis sinensis , and Opisthorchis sp. ). Skin irritations and lesions can also be caused by trematodes that normally infect other species. Animal health concerns include parasites that affect the eyes of waterfowl ( Philophthalmus megalurus ), a trematode that burrows into the cartilage of fish and can lead to death ( Centrocestus formosanus ), and a trematode that infects the muscle tissue of fish and causes multiple abnormalities ( Haplorchis sp. ). When parasite-infected fish or crustaceans are eaten by birds or mammals, the next stage of the life cycle is in place (fig. 2). Native snail species concerns include the potential displacement of invertebrate species that make up the natural nearshore benthic communities in BNP. M. tuberculatus has very high reproductive rates, reproduces via parthenogenesis, and is live bearing, factors which increase the survivability of the offspring and increase competition for limited resources. These snails are considered to be freshwater animals in their native habitat of Southeast Asia. However, they have been collected in BNP in both estuarine and marine waters along the western margins of BNP and, as far as 1.7 kilometers (km) from shore at the Black Point canal inflow into Biscayne Bay (383 live per square meter (/m 2 ). In BNP, M. tuberculatus is a benthic inhabitant grazing on micro algal components at the sediment surface. A documented population with as many as 23,000/m 2 was observed at Snapper Creek, near Coral Gables, FL (Roessler and others, 1977), north of BNP.

Florida↗

USGS2011

DS-Software for analyzing data collected using double sampling

DS analyzes count data to estimate density or relative density and population size when appropriate. The software is no longer available. The software was designed to analyze data collected using double sampling, but it also can be used to analyze index data. DS is not currently configured to apply distance methods or methods based on capture-recapture theory. Double sampling for the purpose of this report means surveying a sample of locations with a rapid method of unknown accuracy and surveying a subset of these locations using a more intensive method assumed to yield unbiased estimates. "Detection ratios" are calculated as the ratio of results from rapid surveys on intensive plots to the number actually present as determined from the intensive surveys. The detection ratios are used to adjust results from the rapid surveys. The formula for density is (results from rapid survey)/(estimated detection ratio from intensive surveys). Population sizes are estimated as (density)(area). Double sampling is well-established in the survey sampling literature—see Cochran (1977) for the basic theory, Smith (1995) for applications of double sampling in waterfowl surveys, Bart and Earnst (2002, 2005) for discussions of its use in wildlife studies, and Bart and others (in press) for a detailed account of how the method was used to survey shorebirds across the arctic region of North America. Indices are surveys that do not involve complete counts of well-defined plots or recording information to estimate detection rates (Thompson and others, 1998). In most cases, such data should not be used to estimate density or population size but, under some circumstances, may be used to compare two densities or estimate how density changes through time or across space (Williams and others, 2005). The Breeding Bird Survey (Sauer and others, 2008) provides a good example of an index survey. Surveyors record all birds detected but do not record any information, such as distance or whether each bird is recorded in subperiods, that could be used to estimate detection rates. Nonetheless, the data are widely used to estimate temporal trends and spatial patterns in abundance (Sauer and others, 2008). DS produces estimates of density (or relative density for indices) by species and stratum. Strata are usually defined using region and habitat but other variables may be used, and the entire study area may be classified as a single stratum. Population size in each stratum and for the entire study area also is estimated for each species. For indices, the estimated totals generally are only useful if (a) plots are surveyed so that densities can be calculated and extrapolated to the entire study area and (b) if the detection rates are close to 1.0. All estimates are accompanied by standard errors (SE) and coefficients of variation (CV, that is, SE/estimate).

Open-File Report↗