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At least 109 records · Page 6Linked to original sources
USGS2019

Benthic community dynamics in Coyote Creek and Artesian Slough, southern San Francisco Bay, California, May 2016 to March 2018

The primary objective of this study is to quantify current (2016–18) benthic-community structure and function in the southern San Francisco Bay, and to compare those communities to the communities in the neighboring sloughs. The study area is inclusive of the area south of the Dumbarton Bridge including Coyote Creek and Artesian Slough. The southern San Francisco Bay is a system dependent on phytoplankton as the base to the food web. Despite abundant nutrients, southern San Francisco Bay has had limited phytoplankton production in the last several decades owing to poor light conditions caused by high turbidities, and high grazing losses from the water column by benthic invertebrates and zooplankton. However, the balance of biogeochemical conditions during spring of most years accommodates a short phytoplankton bloom in the southern San Francisco Bay. This balance between available light, nutrients, and grazing has maintained the phytoplankton biomass in the southern San Francisco Bay at low levels relative to other high-nutrient urban estuaries. The role of benthic invertebrates during episodic spring events, as well as in other seasons, remains of great interest to water-quality and biological resource managers.

California↗
USGS1981

Surface-water quality, Twin Ponies watershed, Pottawattamie and Mills Counties, Iowa

Existing surface-water quality in the Twin Ponies watershed is significantly affected by runoff from agricultural lands that comprise most of the area. Runoff effects include the addition of phosphate, organic nitrogen, fecal bacteria, trace metals, pesticides and notably suspended sediment to streaMflow, because runoff commonly is a transport mechanism for these constituents. Low-flow water quality generally is characterized by dissolvedoxygen concentrations near saturation, dissolved-solids concentrations of about 450 milligrams per liter, suspendedsediment concentrations less than 200 milligrams per liter, and a pH of 8.2. However~ samples collected during runoff contained biological and chemical concentrations 10 to 30 times greater than concentrations obtained from samples collected during periods of low flow. Suspended-sediment concentrations obtained during runoff ranged froM 1,000 to 7,000 milligrams per liter. Iowa Class "B" standards for dissolved oxygen, ammonia, fecal coliforms, chromium, copper, lead, and mercury in streams were exceeded in numerous samples collected during runoff. It is probable that the variations between constituent concentrations in samples collected during runoff and those collected during low flow will be similar after grade-stabilization structures have been constructed on streams and after land-treatment measures have been implemented in the watershed as proposed by the U.S. Soil Conservation Service. Grade-stabilization structures should reduce gully and channel erosion in the watershed by dissipating the erosive energy of streamflow during significant runoff. Land-treatment measures to be implemented in conjunction with the project would help reduce sediment yield to stream channels. With the impoundments~ a decrease in velocity of the in-flowing water should produce a decrease of both the suspended~sediment concentrations and the chemical and biological constituents associated with the suspended sediMent in the impounded water.

Iowa↗
USGS2019

Observations on the range and nesting biology of the Mexican endemic rufous-capped brush-finch (Atlapetes Pileatus Pileatus)

The Rufous-capped Brush-finch ( Atlapetes pileatus ) is a species endemic to Mexico, whose breeding biology has received little attention. We studied two nests of the nominate subspecies from the mountains of southern Sonora. Nests were untidy, broad, open cups, placed in low, thick vegetation. Clutch size at one nest consisted of three immaculate white eggs. The second nest contained two Brush-finch nestlings and one cowbird ( Molothrus sp.) nestling. Both parents brought food to the nestlings, but delivered significantly more food to the cowbird nestling. Most of our observations of nest architecture, egg coloration, and adult behaviors are consistent with previous descriptions for Rufous-capped Brush-finch and other members of the genus Atlapetes . This is the first report of cowbird brood-parasitism on the Rufous-capped Brush-finch, as well as the first confirmed record of breeding by this species in Sonora.

Ornitología Neotropical↗
USGS1996

Measuring and monitoring biological diversity: Standard methods for mammals

Measuring and Monitoring Biological Diversity: Standard Methods for Mammals provides a comprehensive manual for designing and implementing inventories of mammalian biodiversity anywhere in the world and for any group, from rodents to open-country grazers. The book emphasizes formal estimation approaches, which supply data that can be compared across habitats and over time. Beginning with brief natural histories of the twenty-six orders of living mammals, the book details the field techniques—observation, capture, and sign interpretation—appropriate to different species. The contributors provide guidelines for study design, discuss survey planning, describe statistical techniques, and outline methods of translating field data into electronic formats. Extensive appendixes address such issues as the ethical treatment of animals in research, human health concerns, preserving voucher specimens, and assessing age, sex, and reproductive condition in mammals. Useful in both developed and developing countries, this volume and the Biological Diversity Handbook Series as a whole establish essential standards for a key aspect of conservation biology and resource management.

Book↗
USGS2024

In situ allelopathic expression by the invasive amphibious plant, Ludwigia hexapetala (water primrose) across habitat types, seasons, and salinities

Broad infestations of invasive, non-native vegetation have transformed wetlands around the world. Ludwigia hexapetala is a widespread, amphibious invasive plant with a creeping growth habit in open water and an erect growth habit in terrestrial habitats. In the upper San Francisco Estuary of California, L. hexapetala is increasingly terrestrializing into marshes and this expansion may be facilitated by allelopathy. We conducted the first field-based study on L. hexapetala allelopathy to determine whether (1) three allelochemicals known to be exuded by L. hexapetala are expressed in situ, (2) the allelochemicals are detectable in leaves, soil, and water, and (3) allelopathic expression varies by season, salinity, and growth habit (open water “patch” vs. terrestrial marsh “interface” locations). Water, soil, and L. hexapetala leaves were collected in two freshwater sites and two oligohaline sites in the upper San Francisco Estuary in summer 2021, fall 2021, and spring 2022. Myricitrin and quercitrin, known allelochemicals, and salipurposid, a newly identified polyphenol, were detected in water, soil, and leaves. There were significant differences in allelochemical concentrations under fresh versus oligohaline conditions in water and soil, but not leaves. All three allelochemicals generally had higher concentrations in patch versus interface locations, suggesting that L. hexapetala allelopathy plays a greater competitive role in open water than terrestrial habitats. Leaf concentrations of each allelochemical varied seasonally; however, both myricitrin and salipurposid had heightened concentrations in spring. These results suggest that herbicide application in early spring may be most effective in controlling L. hexapetala terrestrialization from open water to marshes.

California↗
USGS2020

Integrating side-scan sonar and acoustic telemetry to estimate the annual spawning run size of Atlantic sturgeon in the Hudson River

There is considerable interest in evaluating the status and trends of sturgeon populations, yet many traditional approaches to estimating the abundance of fishes are intractable due to their biology and rarity. Side-scan sonar has recently emerged as an effective tool for censusing sturgeon in rivers, yet challenges remain for censusing open populations that may visit specific habitats over periods of time (e.g., spawning runs). We use a hierarchical model to integrate side-scan sonar with acoustic telemetry, to estimate the proportion of a spawning run fitted with acoustic tags (12%; 95% CRI = 8-16%) and extrapolate to the total run size in 2014. Our investigation represents a novel approach to generating run size estimates in a large river and provides the first estimate of Atlantic sturgeon spawning run size for the Hudson River (N ̂ = 466; 95% CRI = 310-745) since the fishery moratorium in the 1990’s. Our estimate suggests that the Hudson River holds one of the largest contemporary populations of Atlantic sturgeon, but also indicates that it remains sharply depleted relative to virgin conditions.

Hudson River↗
USGS1996

Thermoregulatory effects of radiotelemetry transmitters on mallard ducklings

Many telemetry transmitter attachments disrupt downy insulation, and may bias survival studies during cold weather by making ducklings more susceptible to chilling. We compared thermal responses of untreated 1-day-old mallards ( Anas platyrhynchos ) to ducklings carrying external sutured backpack or subcutaneously implanted transmitters. Ducklings carrying external transmitters showed areas of increased surface temperature in thermographic images. However, open-circuit respirometry studies at 5, 10, 15, 20, and 25 C and wind speeds of 0.1, 0.2, 0.5, and 1 m/s indicated no biologically significant differences in total heat production, net heat production, or short-term body mass loss. These results do not exclude the possibility of other negative effects of transmitters on duckling behavior and survival.

Journal of Wildlife Management↗
USGS2007

Mapping and vessel-based capabilities

U.S. Geological Survey (USGS) scientists from the Florida Integrated Science Center (FISC) conduct scientific investigations of submerged coastal and marine resources using new and existing technologies. Each contributing technique, method, or product adds to our understanding of coastal and marine resources and provides information for resource-management decisionmaking. In support of this mission, the USGS St. Petersburg office maintains a fleet of research vessels used for inland, coastal, and open-water marine surveys and investigations. Each vessel has advantages and limitations related to water depth, carrying capacity, speed, operation in open water, and other functions. These research platforms are staffed by experienced technical and scientific professionals with expertise in marine navigation, geology, geophysics, engineering, biology, and oceanography.

Fact Sheet↗
USGS2001

Rainfall, Streamflow, and Water-Quality Data During Stormwater Monitoring, Halawa Stream Drainage Basin, Oahu, Hawaii, July 1, 2000 to June 30, 2001

The State of Hawaii Department of Transportation Stormwater Monitoring Program was implemented on January 1, 2001. The program includes the collection of rainfall, streamflow, and water-quality data at selected sites in the Halawa Stream drainage basin. Rainfall and streamflow data were collected from July 1, 2000 to June 30, 2001. Few storms during the year met criteria for antecedent dry conditions or provided enough runoff to sample. The storm of June 5, 2001 was sufficiently large to cause runoff. On June 5, 2001, grab samples were collected at five sites along North Halawa and Halawa Streams. The five samples were later analyzed for nutrients, trace metals, oil and grease, total petroleum hydrocarbons, fecal coliform, biological and chemical oxygen demands, total suspended solids, and total dissolved solids.

Open-File Report↗
USGS1981

Water-quality assessment of Cache Creek, Yolo, Lake, and Colusa counties, California

Cache Creek and its tributaries from Clear Lake to Yolo Bypass have been the subject of quality and quantity of water studies by several governmental agencies since the early 1900's. Water-quality data from these studies showed that water in the basin is of good quality for most of the beneficial uses defined by the California State Water Resources Control Board. Concentrations of dissolved constituents are substantially higher in the water in the two largest tributaries than in Cache Creek. Seasonal variations in dissolved constituents are also greater in the tributaries than in Cache Creek. Clear Lake has a major effect on water quality, resulting in little seasonal fluctuation in water quality in Cache Creek. Excessive voron and suspended-sediment concentrations are the greatest water-quality problems, according to existing data. Both of these problems are from natural sources. Water-quality monitoring is presently being conducted monthly at four sites by the California Department of Water Resurces and at several other sites by other agencies. Modifications in current monitoring are proposed to gain further information on diel dissolved-oxygen cycles, pesticides, and biological constituents that may adversely affect beneficial uses. (USGS)

Open-File Report↗
USGS2005

Two-stage sequential sampling: A neighborhood-free adaptive sampling procedure

Designing an efficient sampling scheme for a rare and clustered population is a challenging area of research. Adaptive cluster sampling, which has been shown to be viable for such a population, is based on sampling a neighborhood of units around a unit that meets a specified condition. However, the edge units produced by sampling neighborhoods have proven to limit the efficiency and applicability of adaptive cluster sampling. We propose a sampling design that is adaptive in the sense that the final sample depends on observed values, but it avoids the use of neighborhoods and the sampling of edge units. Unbiased estimators of population total and its variance are derived using Murthy's estimator. The modified two-stage sampling design is easy to implement and can be applied to a wider range of populations than adaptive cluster sampling. We evaluate the proposed sampling design by simulating sampling of two real biological populations and an artificial population for which the variable of interest took the value either 0 or 1 (e.g., indicating presence and absence of a rare event). We show that the proposed sampling design is more efficient than conventional sampling in nearly all cases. The approach used to derive estimators (Murthy's estimator) opens the door for unbiased estimators to be found for similar sequential sampling designs. ?? 2005 American Statistical Association and the International Biometric Society.

Journal of Agricultural, Biological, and Environme↗
USGS2017

Is GPS telemetry location error screening beneficial?

The accuracy of global positioning system (GPS) locations obtained from study animals tagged with GPS monitoring devices has been a concern as to the degree it influences assessments of movement patterns, space use, and resource selection estimates. Many methods have been proposed for screening data to retain the most accurate positions for analysis, based on dilution of precision (DOP) measures, and whether the position is a two dimensional or three dimensional fix. Here we further explore the utility of these measures, by testing a Telonics GEN3 GPS collar's positional accuracy across a wide range of environmental conditions. We found the relationship between location error and fix dimension and DOP metrics extremely weak (r 2 adj ∼ 0.01) in our study area. Environmental factors such as topographic exposure, canopy cover, and vegetation height explained more of the variance (r 2 adj = 15.08%). Our field testing covered sites where sky-view was so limited it affected GPS performance to the degree fix attempts failed frequently (fix success rates ranged 0.00–100.00% over 67 sites). Screening data using PDOP did not effectively reduce the location error in the remaining dataset. Removing two dimensional fixes reduced the mean location error by 10.95 meters, but also resulted in a 54.50% data reduction. Therefore screening data under the range of conditions sampled here would reduce information on animal movement with minor improvements in accuracy and potentially introduce bias towards more open terrain and vegetation.

Wildlife Biology↗
USGS2012

2008 Joint United States-Canadian program to explore the limits of the Extended Continental Shelf aboard the U.S. Coast Guard cutter Healy --Cruise HLY0806

In September 2008, the U.S. Geological Survey (USGS), in cooperation with Natural Resources Canada, Geological Survey of Canada (GSC), conducted bathymetric and geophysical surveys in the Arctic Beaufort Sea aboard the U.S. Coast Guard cutter USCGC Healy . The principal objective of this mission to the high Arctic was to acquire data in support of delineation of the outer limits of the U.S. and Canadian Extended Continental Shelf (ECS) in the Arctic Ocean in accordance with the provisions of Article 76 of the Law of the Sea Convention. The Healy was accompanied by the Canadian Coast Guard icebreaker Louis S. St- Laurent . The science parties on the two vessels consisted principally of staff from the USGS ( Healy ), and the GSC and the Canadian Hydrographic Service ( Louis ). The crew included marine mammal and Native-community observers, ice observers, and biologists conducting research of opportunity in the Arctic Ocean. The joint survey proved an unqualified success. The Healy collected 5,528 km of swath (multibeam) bathymetry (38,806 km 2 ) and CHIRP subbottom profile data, with accompanying marine gravity measurements. The Louis acquired 2,817 km of multichannel seismic (airgun) deep-penetration reflection-profile data along 12 continuous lines, as well as 35 sonobuoy refraction stations and accompanying single-beam bathymetry. The coordinated efforts of the two vessels resulted in seismic-reflection profile data of much higher quality and continuity than if the data had been acquired with a single vessel alone. Equipment failure rate of the seismic equipment gear aboard the Louis was greatly improved with the advantage of having a leading icebreaker. When ice conditions proved too severe to deploy the seismic system, the Louis led the Healy , resulting in much improved quality of the swath bathymetry and CHIRP sub-bottom data in comparison with data collected by the Healy in the lead or working alone. Ancillary science objectives, including ice observations, deployment of ice-monitoring buoys and water-column sampling for biologic (phytoplankton) studies, were also successfully accomplished.

Open-File Report↗
USGS2016

Observations of recruitment and colonization by tunicates and associated invertebrates using giant one-meter 2 recruitment plates at Woods Hole, Massachusetts

Large recruitment plates measuring 1 × 1 m were deployed over an 18-month period from September 2013 to March 2015 for the purpose of documenting recruitment and colonization processes of marine invertebrate species at Woods Hole, Massachusetts. Each side of two plates was subdivided into 16 subareas (25 × 25 cm), and an observational strategy was developed whereby, at approximately two-week intervals, a different subarea was cleaned. Using this approach, we were able to photographically document species recruitment and growth interactions. Water temperature records from the site show that steady warming and cooling between 3 and 20° C changed at a mean rate of 0.2 ° C d -1 . However, temperature changes during the coolest and warmest parts of the temperature cycle were highly variable. In 2014, between the first and last occurrence of 0° C, temperatures were ≤0° C 15 percent of the time, but in 2015 temperatures were ≤0° C 93 percent of the time. In 2014, between the first and last occurrence of 21° C, temperatures were ≥21° C 88 percent of the time, and this warm period correlated with the disappearance of the hydroid Ectopleura crocea , the solitary tunicates Ascidiella aspersa and Ciona intestinalis , and the 2013 generation of Botrylloides violaceus . In Woods Hole, large plates provided enough space to accommodate both fast- and slow-colonizing species, resulting in the establishment of a diverse assemblage that was observed over a long time period. The most successful colonizing species had relatively long reproductive and recruitment periods, grew rapidly, repelled settlement onto their surfaces by larvae of any species, defended themselves against overgrowth by any species, overwintered, and lived a long time. Of the three dominant species observed in this study, the colonial tunicates Didemnum vexillum and Botrylloides violaceus had these qualities; the encrusting colonial bryozoan Schizoporella unicornis had all but one, it grew more slowly than the others. Barnacles constituted the only biological substrate that was effectively colonized by other species, both by larval recruitment and overgrowth. In Woods Hole, after a substrate had become fully colonized, there was very little opportunity for new recruitment or colony growth until new substrate opened after the death of colonies and individuals and the disappearance of biogenic structures such as amphipod tubes. An understanding of colonization processes utilized by invasive species allows prediction of their potential effects on ecosystems in areas where they are not yet present.

Massachusetts↗