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USGS2008

Age-class structure and variability of two populations of the bluemask darter etheostoma (Doration) sp.

The bluemask darter Etheostoma ( Doration ) sp. is an endangered fish endemic to the upper Caney Fork system in the Cumberland River drainage in central Tennessee. Darters ( Etheostoma spp.) are typically short-lived and exhibit rapid growth that quickly decreases with age. Consequently, estimating age of darters from length-frequency distributions can be difficult and subjective. We used a nonparametric kernel density estimator to reduce subjectivity in estimating ages of bluemask darters. Data were collected from a total of 2926 bluemask darters from the Collins River throughout three growing seasons. Additionally, data were collected from 842 bluemask darters from the Rocky River during one growing season. Analysis of length-frequencies indicated the presence of four age classes in both rivers. In each river, the majority of the population was comprised of fish <3 y old. Some age-one individuals were sexually mature, but the majority of the reproductive population was comprised of older fish. Differences in age-class structure among years reflected variable year-class strength in the Collins River that seemed related to summer discharge. Male and female growth rates differed significantly (P < 0.05); males were typically larger than females of the same age after the first growing season and the majority of age-three individuals were males. Growth rates in the Collins and Rocky Rivers were similar for each sex (P > 0.05). In both rivers, females were more abundant than males.

Tennessee↗

USGS2024

Survey effort and targeted landbird community metrics at Indiana lowland forest restoration sites

Many sampling and analytical methods can estimate the abundance, distributions, and diversity of birds and other wildlife. However, challenges with sample size and analytical capacity can make these methods difficult to implement for resource-limited monitoring programs. To apprise efficient and attainable sampling designs for landbird monitoring programs with limited observational data, we used breeding season bird point survey data collected in 2016 at four forest restoration sites in Indiana, USA. We evaluated three subsets of observed species richness, total possibly breeding landbirds, Partners in Flight Regional Conservation Concern (PIF RCC) landbirds, and interior forest specialists (IFSs). Simulated surveys based on field data were used to conduct Bayesian Michaelis–Menten curve analyses estimating observed species as a function of sampling effort. On comparing simulated survey sets with multiple habitat types versus those with one habitat, we found that those with multiple habitat types had estimated 39%–83% greater observed PIF RCC species richness and required 41%–55% fewer visits per point to observe an equivalent proportion of PIF RCC species. Even with multiple habitats in a survey set, the number of visits per point required to detect 50% of observable species was 30% higher for PIF RCC species than for total breeding landbird species. Low detection rates of IFS species at two field sites made precise estimation of required effort to observe these species difficult. However, qualitatively, we found that only sites containing mature forest fragments had detections of several bird species designated as high-confidence IFS species. Our results suggest that deriving specialized species diversity metrics from point survey data can add value when interpreting those data. Additionally, designing studies to collect these metrics may require explicitly planning to visit multiple habitat types at a monitoring site and increasing the number of visits per survey point.

Indiana↗

USGS2018

Reproductive success and contaminant associations in tree swallows (Tachycineta bicolor) used to assess a Beneficial Use Impairment in U.S. and Binational Great Lakes’ Areas of Concern

During 2010-2014, tree swallow (Tachycineta bicolor) reproductive success was monitored at 68 sites across all 5 Great Lakes, including 58 sites located within Great Lakes Areas of Concern (AOCs) and 10 non-AOCs. Sample eggs were collected from tree swallow clutches and analyzed for contaminants including polychlorinated biphenyls (PCBs), dioxins and furans, polybrominated diphenyl ethers, and 34 other organic compounds. Contaminant data were available for 360 of the clutches monitored. Markov chain multistate modeling was used to assess the importance of 5 ecological variables and 11 of the dominant contaminants in explaining the pattern of egg and nestling failure rates. Four of 5 ecological variables (Female Age, Date within season, Year, and Site) were important explanatory variables. Of the 11 contaminants, only total dioxin and furan toxic equivalents (TEQs) explained a significant amount of the egg failure probabilities. Neither total PCBs nor PCB TEQs explained the variation in egg failure rates. In a separate analysis, polycyclic aromatic hydrocarbon exposure in nestling diet, used as a proxy for female diet during egg laying, was significantly correlated with the daily probability of egg failure. The 8 sites within AOCs which had poorer reproduction when compared to 10 non-AOC sites, the measure of impaired reproduction as defined by the Great Lakes Restoration Initiative, were associated with exposure to dioxins and furan TEQs, PAHs, or depredation. Only 2 sites had poorer reproduction than the poorest performing non-AOC. Using a classic (non-modeling) approach to estimating reproductive success, 82% of nests hatched at least 1 egg, and 75% of eggs laid, excluding those collected for contaminant analyses, hatched.

Great Lakes↗

USGS2002

Use of regional climate model output for hydrologic simulations

Daily precipitation and maximum and minimum temperature time series from a regional climate model (RegCM2) configured using the continental United States as a domain and run on a 52-km (approximately) spatial resolution were used as input to a distributed hydrologic model for one rainfall-dominated basin (Alapaha River at Statenville, Georgia) and three snowmelt-dominated basins (Animas River at Durango. Colorado; east fork of the Carson River near Gardnerville, Nevada: and Cle Elum River near Roslyn, Washington). For comparison purposes, spatially averaged daily datasets of precipitation and maximum and minimum temperature were developed from measured data for each basin. These datasets included precipitation and temperature data for all stations (hereafter, All-Sta) located within the area of the RegCM2 output used for each basin, but excluded station data used to calibrate the hydrologic model. Both the RegCM2 output and All-Sta data capture the gross aspects of the seasonal cycles of precipitation and temperature. However, in all four basins, the RegCM2- and All-Sta-based simulations of runoff show little skill on a daily basis [Nash-Sutcliffe (NS) values range from 0.05 to 0.37 for RegCM2 and -0.08 to 0.65 for All-Sta]. When the precipitation and temperature biases are corrected in the RegCM2 output and All-Sta data (Bias-RegCM2 and Bias-All, respectively) the accuracy of the daily runoff simulations improve dramatically for the snowmelt-dominated basins (NS values range from 0.41 to 0.66 for RegCM2 and 0.60 to 0.76 for All-Sta). In the rainfall-dominated basin, runoff simulations based on the Bias-RegCM2 output show no skill (NS value of 0.09) whereas Bias-All simulated runoff improves (NS value improved from - 0.08 to 0.72). These results indicate that measured data at the coarse resolution of the RegCM2 output can be made appropriate for basin-scale modeling through bias correction (essentially a magnitude correction). However, RegCM2 output, even when bias corrected, does not contain the day-to-day variability present in the All-Sta dataset that is necessary for basin-scale modeling. Future work is warranted to identify the causes for systematic biases in RegCM2 simulations, develop methods to remove the biases, and improve RegCM2 simulations of daily variability in local climate.

Journal of Hydrometeorology↗

USGS1965

Additional records of aspergillosis among passerine birds in Maryland and the Washington, DC metropolitan area

Two cases of aspergillosis involving four adult cowbirds ( Molothrus ater ) collected during the nesting season are reported. Aspergillosis was found in house sparrows ( Passer domesticus ) on two occasions.

Maryland↗

USGS1976

Water-quality study of a reach of the Merced River in Yosemite National Park and vicinity, California, April 1973 through September 1974

A 25-mile (40-kilometre) reach of the Merced River was studied to provide the National Park Service with water-quality data prior to the operation of a new sewage-treatment plant. Data were collected periodically at four Merced River and two inflow stations. Discharge varied seasonally with highest flow occurring at the time of spring snowmelt runoff. Lowest flow occurred during late summer, coinciding with high park visitor use and elevated water temperature. Water-quality variables investigated were discharge, temperature, major chemical constituents, selected trace metals, specific conductance, suspended sediment, turbidity, dissolved oxygen, pH, alkalinity, carbon dioxide, total organic carbon, nitrogen, phosphorus, algal growth potential, coliform bacteria, periphyton, and benthic invertebrates. Diel measurements were made at some stations to delineate daily fluctuations in selected water-quality variables. Results indicate that water in the reach of the Merced River studied was of good quality. The river had low concentrations of dissolved solids (8 to 41 milligrams per litre) and low alkalinity values (2 to 24 milligrams per litre of alkalinity as CaCO 3 ). Mean concentrations of nitrogen and phosphorus were highest in the Merced River at Rancheria Flat. Algal growth potential tests showed that phosphorus was limiting algal growth at Happy Isles Bridge, El Capitan Bridge, and South Fork Merced River, whereas nitrogen was limiting growth at Rancheria Flat. Input of excessive nitrogen and phosphorus concentrations in the Merced River during the summer low-flow period, and mixing with warm tributary inflow could cause excessive algal growth and production. The algal types found were diatoms, green algae, and blue-green algae. Biomass/chlorophyll a ratios in the Merced River were low (0.3 to 7.7). Benthic invertebrates consisted chiefly of Diptera, Ephemeroptera, and Plecoptera.

California↗

USGS2014

Sources, transport, and trends for selected trace metals and nutrients in the Coeur d'Alene and Spokane River Basins, Idaho, 1990-2013

Data collected at 18 streamflow-gaging and water-quality sampling sites in the Coeur d’Alene and Spokane River Basins of northern Idaho were used to estimate mean streamflow‑weighted concentrations and annual loads of total and dissolved cadmium, lead, and zinc, and total phosphorus (TP) and nitrogen (TN) for water years (WYs) 2009–13. Chronic Ambient Water Quality Criteria (AWQC) and AWQC ratios also were calculated to evaluate Idaho aquatic life criteria for chronic exposure to cadmium and zinc in streams. At four sites with a longer period of record, a Seasonal Kendall trend test was used to assess historical trends in the concentrations of total cadmium, lead, and zinc, and chronic AWQC ratios for cadmium and zinc during WYs 1990–2013. Concentrations of dissolved and total cadmium, lead, and zinc varied widely both at and among sites. At most sites, dissolved cadmium and zinc constituted most of the total concentrations; dissolved lead generally constituted less than 10 percent of the total lead concentration. Trace metal concentrations increased by 2 to 4 orders of magnitude along the South Fork Coeur d’Alene River (SFCDR) from near Mullan (site 2) downstream to near Pinehurst (site 13). The mean streamflow-weighted concentrations of total cadmium, lead, and zinc in the SFCDR near Pinehurst for WYs 2009–13 were 3.71, 61.4, and 514 micrograms per liter (μg/L), respectively. In the Coeur d’Alene River (CDR) near Harrison (site 15), downstream of the confluence of the metal-enriched SFCDR and the relatively dilute North Fork Coeur d’Alene River (NFCDR), the mean streamflow-weighted concentrations of total cadmium, lead, and zinc were 1.58, 125, and 236 μg/L, respectively. Trace‑metal concentrations were smaller in the Spokane River than in the CDR because of dilution and retention of trace metals in Coeur d’Alene Lake. The mean streamflow-weighted concentrations of total cadmium, lead, and zinc in the Spokane River near Post Falls (site 18) were 0.231, 2.91, and 48.9 μg/L, respectively. AWQC ratios indicate that cadmium and zinc concentrations met the chronic criteria (ratio of less than 1.0) for the protection of aquatic life at only three sites: the NFCDR at Enaville (site 1), the upper SFCDR near Mullan (site 2), and the St. Joe River near St. Maries (site 16). Cadmium and zinc concentrations at sites on the Spokane River (sites 17 and 18) generally were close to the chronic AWQC values. The sites with the largest chronic AWQC ratios in the Coeur d’Alene and Spokane River Basins for both cadmium and zinc were in the Canyon and Ninemile Creek basins (sites 3–6). Concentrations of TP and TN generally were low along the SFCDR downstream to Kellogg. From the SFCDR near Kellogg (site 9) downstream to the SFCDR above Pine Creek (site 11), the mean streamflow-weighted concentration of the nutrients TP and TN increased by 0.036 milligram per liter (mg/L) (200 percent) and 0.124 mg/L (78 percent), respectively. The increases in nutrient concentrations along the SFCDR likely are in response to discharge from wastewater‑treatment facilities. Mean streamflow-weighted concentrations for TP and TN (0.054 and 0.284 mg/L, respectively) were the highest in the sampling network in the SFCDR above Pine Creek (site 11). LOADEST modeling was used to relate mass transport, or load, of trace metals and nutrients to variations in streamflow and time. Results indicate that most of the cadmium and zinc load in the Coeur d’Alene and Spokane Rivers is derived from the SFCDR, and that most of the lead load is derived from the Coeur d’Alene River downstream of the confluence of the NFCDR and SFCDR. Major tributary sources of trace metals to the SFCDR are Canyon Creek and Ninemile Creek. Combined, these two tributaries contributed estimated mean loads of about 0.575 ton per year (ton/yr) of total cadmium, 5.29 ton/yr of total lead, and 90.9 ton/yr of total zinc to the SFCDR during WYs 2009–13. Groundwater discharge and tributaries near the Central Impoundment Area between SFCDR near Kellogg (site 9) and SFCDR near Smelterville (site 10) were other primary sources of cadmium and zinc. Combined, these sources contributed an estimated 1.39 ton/yr of total cadmium and 143 ton/yr of total zinc to the SFCDR during WYs 2009–13. Erosion and transport of sediment-bound lead contained in the CDR flood plain and on the river bottom between Cataldo (site 14) and Harrison (site 15) were the primary source of lead. During WYs 2009–13, the mean load of trace metals delivered to Coeur d’Alene Lake included about 4.66 ton/yr of total cadmium, 398 ton/yr of total lead, and 698 ton/yr of total zinc. About 99 percent of the trace-metal load to the lake was from the CDR as measured near site 15 at Harrison. During WYs 2009–13, about 1.48 ton/yr of cadmium, 18 ton/yr of lead, and 350 ton/yr of zinc were transported from Coeur d’Alene Lake into the Spokane River as measured at the lake outlet (site 17). During WYs 2009–13, the loads of TP and TN delivered from the Coeur d’Alene and St. Joe Rivers to Coeur d’Alene Lake were about equivalent. On average, the CDR transported about 93.6 tons of TP and 369 tons of TN, and the St. Joe River transported about 92.9 tons of TP and 360 tons of TN to the lake during 2009–13. About 52.9 ton/yr of TP and 628 ton/yr of TN were transported from Coeur d’Alene Lake to the Spokane River during WYs 2009–13. Results from Seasonal Kendall trend tests indicate statistically significant downward temporal trends during WYs 1990–2013 for total cadmium, lead, zinc, and chronic AWQC ratios of cadmium and zinc in the SFCDR at Elizabeth Park (site 8) and near Pinehurst (site 13), and in the CDR near Harrison (site 15). Statistically significant downward temporal trends for total lead, zinc, and the chronic AWQC ratio of zinc also occurred in the Spokane River near Post Falls (site 18) during WYs 1991–2013. Seasonal Kendall trend tests for WYs 2003–13 indicated statistically significant downward trends for total cadmium, zinc, and chronic AWQC ratios of cadmium and zinc in the SFCDR at Elizabeth Park (site 8). The Spokane River near Post Falls (site 18) had a statistically significant downward trend for total zinc during WYs 2003–13, and a significant upward trend for the chronic AWQC ratio of cadmium. No significant trends were found in trace-metal concentrations or chronic AWQC ratios in the SFCDR near Pinehurst (site 13) and the CDR near Harrison (site 15) during WYs 2003–13. Results from this study indicate that remedial activities conducted since the 1990s have been successful in reducing the concentrations and loads of trace metals in streams and rivers in the Coeur d’Alene and Spokane River Basins. Soils, sediment, surface water, and groundwater in areas of the Coeur d’Alene and Spokane River Basins are contaminated, and the hydrological relations between these media are complex and difficult to characterize. Trace metals have variable source areas, are transported differently depending on hydrologic conditions, and behave differently in response to remedial activities in upstream basins. Based on these findings, no single remedial action would be completely effective in reducing all trace metals to nontoxic concentrations throughout the Coeur d’Alene and Spokane River Basins. Instead, unique cleanup activities targeted at specific media and specific source areas may be necessary to achieve long-term water-quality goals.

Idaho↗

USGS2018

Simulation of hydrodynamics, water quality, and lake sturgeon habitat volumes in Lake St. Croix, Wisconsin and Minnesota, 2013

Lake St. Croix is a naturally impounded, riverine lake that makes up the last 40 kilometers of the St. Croix River. Substantial land-use changes during the past 150 years, including increased agriculture and urban development, have reduced Lake St. Croix water-quality and increased nutrient loads delivered to Lake St. Croix. A recent (2012–13) total maximum daily load phosphorus-reduction plan set the goal to reduce total phosphorus loads to Lake St. Croix by 20 percent by 2020 and reduce Lake St. Croix algal bloom frequencies. The U.S. Geological Survey, in cooperation with the National Park Service, developed a two-dimensional, carbon-based, laterally averaged, hydrodynamic and water-quality model, CE–QUAL–W2, that addresses the interaction between nutrient cycling, primary production, and trophic dynamics to predict responses in the distribution of water temperature, oxygen, and chlorophyll a. Distribution is evaluated in the context of habitat for lake sturgeon, including a combination of temperature and dissolved oxygen conditions termed oxy-thermal habitat. The Lake St. Croix CE–QUAL–W2 model successfully reproduced temperature and dissolved oxygen in the lake longitudinally (from upstream to downstream), vertically, and temporally over the seasons. The simulated water temperature profiles closely matched the measured water temperature profiles throughout the year, including the prediction of thermocline transition depths (often within 1 meter), the absolute temperature of the thermocline transitions (often within 1.0 degree Celsius), and profiles without a strong thermocline transition. Simulated dissolved oxygen profiles matched the trajectories of the measured dissolved oxygen concentrations at multiple depths over time, and the simulated concentrations matched the depth and slope of the measured concentrations. Additionally, trends in the measured water-quality data were captured by the model simulation, gaining some potential insights into the underlying mechanisms of critical Lake St. Croix metabolic processes. The CE–QUAL–W2 model tracked nitrate plus nitrite, total nitrogen, and total phosphorus throughout the year. Inflow nutrient contributions (loads), largely dominated by upstream St. Croix River loads, were the most important controls on Lake St. Croix water quality. Close to 60 percent of total phosphorus to the lake was from phosphorus derived from organic matter, and about 89 percent of phosphorus to Lake St. Croix was delivered by St. Croix River inflows. The Lake St. Croix CE–QUAL–W2 model offered potential mechanisms for the effect of external and internal loadings on the biotic response regarding the modeled algal community types of diatoms, green algae, and blue-green algae. The model also suggested the seasonal dominance of blue-green algae in all four pools of the lake. A sensitivity analysis was completed to test the total maximum daily load phosphorus-reduction scenario responses of total phosphorus and chlorophyll a. The modeling indicates that phosphorus reductions would result in similar Lake St. Croix reduced concentrations, although chlorophyll a concentrations did not decrease in the same proportional amounts as the total phosphorus concentrations had decreased. The smaller than expected reduction in algal growth rates highlighted that although inflow phosphorus loads are important, other constituents also can affect the algal response of the lake, such as changes in light penetration and the breakdown of organic matter releasing nutrients. The available habitat suitable for lake sturgeon was evaluated using the modeling results to determine the total volume of good-growth habitat, optimal growth habitat, and lethal temperature habitat. Overall, with the calibrated model, the fish habitat volume in general contained a large proportion of good-growth habitat and a sustained period of optimal growth habitat in the summer. Only brief periods of lethal oxy-thermal habitat were present in Lake St. Croix during the model simulation.

Minnesota, Wisconsin↗

USGS1952

Preliminary summary of reconnaissance for uranium on the Seward Peninsula, Alaska, During 1951

Reconnaissance examinations for uranium were made at nine localities in the York, Nome, and Koyuk districts of the Seward Peninsula, Alaska, during .the 1951 field season. In addition carborne radiometric traverses were made of four roads in the Nome and Council districts. Only at Brooks Mountain in the York district are uranium-bearing deposits that required detailed study. On the southwest flank of Brooks Mountain, zeunerite occurs as a surface coating on quartz-tourmaline veins occupying joint fractures in granite| at a second locality, also on the southwest flank of the mountain, zeunerite is disseminated in a highly-weathered, altered zone of granite near a contact with limestone. Preliminary radiometric analyses show an average of about 0.05 percent equivalent uranium in the vein material and about 0.07 percent equivalent uranium in the weathered, altered granitic zone.

Alaska↗

USGS1980

Water quality of Tampa Bay, Florida, June 1972 - May 1976

A comprehensive assessment of the water quality of Tampa Bay, Florida, was initiated in 1970 to provide background information to evaluate the effects of widening and deepening the ship channel to the port of Tampa. This report provides results of water-quality sampling in the bay from 1972 to 1976, prior to dredging. Measurements of temperature, dissolved oxygen, pH, turbidity, specific conductance, biochemical oxygen demand, and total organic carbon were made as well as measurements for several nutrient, metal, and pesticide parameters. Many parameters were measured at as many as three points in the vertical. These data indicate that Tampa Bay is well-mixed vertically with little density stratification. Time histories of average temperature, dissolved oxygen, pH, turbidity, specific conductance and nutrient values within four subareas of Tampa Bay are given to reveal seasonal or other trends during the period of record. Temperature, dissolved oxygen, pH, turbidity, specific conductance, nutrient, biochemical oxygen demand, total organic carbon, and metal data are also presented as areal distributions. Nutrient concentrations were generally higher in Hillsborough Bay than in other sub-areas of Tampa Bay. Biochemical oxygen demand, total organic carbon, and total organic nitrogen distribution patterns show regions of highest concentrations to be along bay shorelines near population centers. Of the metals analyzed, all were present in concentrations of less than 1 milligram per liter. (USGS)

Florida↗

USGS2003

Climate change and northern prairie wetlands: Simulations of long-term dynamics

A mathematical model (WETSIM 2.0) was used to simulate wetland hydrology and vegetation dynamics over a 32-yr period (1961–1992) in a North Dakota prairie wetland. A hydrology component of the model calculated changes in water storage based on precipitation, evapotranspiration, snowpack, surface runoff, and subsurface inflow. A spatially explicit vegetation component in the model calculated changes in distribution of vegetative cover and open water, depending on water depth, seasonality, and existing type of vegetation. The model reproduced four known dry periods and one extremely wet period during the three decades. One simulated dry period in the early 1980s did not actually occur. Simulated water levels compared favorably with continuous observed water levels outside the calibration period (1990–1992). Changes in vegetative cover were realistic except for years when simulated water levels were significantly different than actual levels. These generally positive results support the use of the model for exploring the effects of possible climate changes on wetland resources.

Limnology and Oceanography↗

USGS2006

Occupancy Estimation and Modeling : Inferring Patterns and Dynamics of Species Occurrence

This is the first book to examine the latest methods in analyzing presence/absence data surveys. Using four classes of models (single-species, single-season; single-species, multiple season; multiple-species, single-season; and multiple-species, multiple-season), the authors discuss the practical sampling situation, present a likelihood-based model enabling direct estimation of the occupancy-related parameters while allowing for imperfect detectability, and make recommendations for designing studies using these models. It provides authoritative insights into the latest in estimation modeling; discusses multiple models which lay the groundwork for future study designs; addresses critical issues of imperfect detectibility and its effects on estimation; and explores the role of probability in estimating in detail.

Book↗

USGS1989

Acid precipitation studies in Colorado and Wyoming: interim report of surveys of montane amphibians and water chemistry

Acid deposition may be detrimental or stressful to native populations of wildlife. Because many species of amphibians breed in shallow ponds created by spring rains or melting snow, they may be particularly vulnerable to the effects of acidification. From 1986 to 1988, we surveyed 105 locations in the central Rocky Mountains where amphibians had been recorded previously, and we found that two species of amphibians had experiences major losses. We found the northern leopard frog ( Rana pipiens ) at only 4 of 33 (12%) historically known localities, and the boreal toad ( Bufo boreas ) was present at 10 of 59 (17%) known localities. Three other species have not suffered region-wide declines. Tiger salamanders ( Ambystoma tigrinum ) and wood frogs ( Rana sylvatica ) were present at 45% and 69% of known localities respectively, and were observed at several localities were they had not been recorded previously. Chorus frogs ( Pseudacris triseriata ) suffered a catastrophic decline in population size in one population monitored since 1961, but regionally, this species was observed in 36 of 56 (64%) known localities and in another 19 localities where there were no previous records. Complete water chemistry was recorded for 41 localities, and pH was measured at 110 sites in total. Acid neutralizing capacity, pH, specific conductivity, and cation concentrations were negatively correlated with elevation. However, in mountain ponds and lakes, pH was rarely less than 6.0 during the amphibian breeding season. We tested the tolerance of embryos of the four species of frogs to low pH. The LC 50 pH was 4.8 for chorus frogs, 4.4-4.7 for leopard frogs, 4.4-4.5 for boreal toads, and 4.2-4.3 for wood frogs. Survival of wood frog embryos declined when exposed to aluminum concentrations of 100 µg/L or greater, but boreal toad embryos survived exposure to aluminum concentrations of 400 µg/L. Acid deposition does not appear to be a major factor in the decline of leopard frogs and boreal toads. However, we have not yet investigated effects of sublethal pH on growth and development of tadpoles. Pollution remains suspect, but other factors, including natural fluctuations in population size, may account for the observed declines.

Colorado;Wyoming↗

USGS2015

Water Quality, Cyanobacteria, and Environmental Factors and Their Relations to Microcystin Concentrations for Use in Predictive Models at Ohio Lake Erie and Inland Lake Recreational Sites, 2013-14

Harmful cyanobacterial “algal” blooms (cyanoHABs) and associated toxins, such as microcystin, are a major water-quality issue for Lake Erie and inland lakes in Ohio. Predicting when and where a bloom may occur is important to protect the public that uses and consumes a water resource; however, predictions are complicated and likely site specific because of the many factors affecting toxin production. Monitoring for a variety of environmental and water-quality factors, for concentrations of cyanobacteria by molecular methods, and for algal pigments such as chlorophyll and phycocyanin by using optical sensors may provide data that can be used to predict the occurrence of cyanoHABs. To test these monitoring approaches, water-quality samples were collected at Ohio recreational sites during May–November in 2013 and 2014. In 2013, samples were collected monthly at eight sites at eight lakes to facilitate an initial assessment and select sites for more intensive sampling during 2014. In 2014, samples were collected approximately weekly at five sites at three lakes. Physical water-quality parameters were measured at the time of sampling. Composite samples were preserved and analyzed for dissolved and total nutrients, toxins, phytoplankton abundance and biovolume, and cyanobacterial genes by molecular methods. Molecular assays were done to enumerate (1) general cyanobacteria, (2) general Microcystis and Dolichospermum ( Anabaena ), (3) mcyE genes for Microcystis , Dolichospermum ( Anabaena ), and Planktothrix targeting deoxyribonucleic acid (DNA), and (4) mcyE transcripts for Microcystis , Dolichospermum ( Anabaena ), and Planktothrix targeting ribonucleic acid (RNA).The DNA assays for the mcyE gene provide data on cyanobacteria that have the potential to produce microcystin, whereas the RNA assays provide data on cyanobacteria that are actively transcribing the toxin gene. Environmental data were obtained from available online sources. Quality-control (QC) samples were collected and analyzed for all constituents to characterize bias and variability; however, QC data for molecular assays were examined in more detail than for the other constituents. The QC data for molecular assays suggested that sampling variability and qPCR variability were small in comparison with the combined variability associated with sample filtering, extraction and purification, and the matrix itself. A total of 46 water-quality samples were collected during 2013 at 8 beach sites—Buck Creek, Buckeye Crystal, Deer Creek, Harsha Main, Maumee Bay State Park (MBSP) Inland (negative control site), MBSP Lake Erie, Port Clinton, and Sandusky Bay. Microcystin was detected in 67–100 percent of samples at all sites except for MBSP Inland, where microcystin was detected in only 20 percent of samples. Microcystin concentrations ranged from <0.10 to 48 micrograms per liter (µ/L), with the widest range found at MBSP Lake Erie and the highest concentrations found at Buckeye Crystal. Saxitoxin was detected in five samples, and cylindrospermopsin was not detected in any samples. A total of 65 water-quality samples were collected during 2014 at 5 sites on 3 lakes—Buckeye Fairfield and Onion Island, Harsha Main and Campers, and MBSP Lake Erie beach. Four of the sites were bathing beaches and one site, Onion Island, was an offshore boater swim area. Concentrations of microcystin ranged from <0.10 to 240 µ/L and, as in 2013, the widest range was found at MBSP Lake Erie. At Buckeye Lake, microcystin concentrations were consistently high (greater than 20 µ/L), ranging from 23 to 81 µ/L. At Harsha Main and Campers, microcystin concentrations ranged from <0.10 to 15 µ/L. Saxitoxin was detected in four samples collected at MBSP Lake Erie. Throughout the 2014 season, the cyanobacterial community, as determined by molecular and microscopy methods, and the dominance associated with the highest microcystin concentrations were unique to individual lakes. At Buckeye Lake, Planktothrix dominated the cyanobacterial community throughout the season and Planktothrix DNA and RNA were found in 100 percent of samples; Microcystis mcyE DNA was found in low concentrations. At Harsha Lake, Dolichospermum and Microcystis were a substantial percentage of the community from late May through August, and the highest microcystin concentrations occurred in June and July. At MBSP Lake Erie, Microcystis generally dominated from mid-July through early November, and the highest microcystin concentrations occurred in August. Spearman’s correlation coefficient (rho) was computed to determine the relations between environmental and water-quality factors and microcystin concentrations at four sites—Buckeye Fairfield, Buckeye Onion Island, Harsha Main, and MBSP Lake Erie. Factors were evaluated for use as potential independent variables in two types of predictive models—daily and long-term models. Easily or continuously measured water-quality factors and available environmental data are used for daily predictions that do not require a site visit. Data from factors used in daily predictions and results from samples collected and analyzed in a laboratory are used for long-term predictions (a few days to several weeks). A few statistically significant correlations (p ≤ 0.05) between microcystin concentrations and factors for both daily and long-term predictions were found at Buckeye Onion Island, and many were found at Harsha Main and MBSP Lake Erie. There were only a few statistically significant factors for daily predictions at Buckeye Fairfield, likely because of the lack of variability in microcystin concentrations. Among factors for daily predictions, phycocyanin had the highest Spearman’s correlation to microcystin concentrations (rho = 0.79 to 0.93) at all sites except for Buckeye Fairfield. Turbidity, pH, algae category, and Secchi depth were significantly correlated to microcystin concentrations at Harsha Main and MBSP Lake Erie. Algae categories were observational categories from 0 (none) to 4 (extreme). Several discharge variables (Maumee River at Waterville, river mouth is approximately 3.5 miles from the beach) at MBSP Lake Erie were promising environmental factors for daily predictions. In addition to discrete water-quality measurements recorded at Harsha Main at the time of sampling, many manipulated measurements (factors derived from mathematical manipulation of time-series data) available from a nearby continuous monitor were strongly correlated to microcystin concentrations; the highest correlation was found for the relation between microcystin concentrations and the antecedent 7-day average phycocyanin (rho = 0.98). For long-term predictions, the most highly correlated molecular assays were Planktothrix mcyE DNA at Buckeye Onion Island and Microcystis mcyE DNA at Harsha Main and MBSP Lake Erie. Concentrations of several nutrient constituents were significantly correlated to microcystin concentrations including total nitrogen at Buckeye Onion Island, ammonia and nitrate plus nitrite (both negatively correlated) at Harsha Main and MBSP Lake Erie, and total phosphorus at MBSP Lake Erie. The results of this study showed that water-quality and environmental variables are promising for use in site-specific daily or long-term predictive models. In order to develop more accurate models to predict toxin concentrations at freshwater lake sites, data need to be collected more frequently and for consecutive days in future studies.

Ohio↗

USGS1997

Evidence of Newell's Shearwater breeding in Puna District, Hawaii

Nocturnal surveys using auditory cues and night-vision equipment were conducted during the seabird breeding season in 1993 to determine use of inland areas in the Puna District, Hawaii by Newell's Shearwater ( Puffinus auricularus newelli ). Two hundred sixty Newell's Shearwater auditory or visual detections were made during 275 survey hours from 23 Jul. 1993 - 20 Sep. 1993. Mean detection rates were 1.26 birds/h at Puulena Crater ( n = 160 Newell's Shearwater detections), 1.05 birds/h at Heiheiahulu ( n = 99) and 0.04 birds/ h at Puu Kaliu ( n = 2). Vocalizing peaked between 50 and 90 min after sunset and 4 h before sunrise. Although night-vision equipment was used on most of the seabird surveys, only 4% of seabirds were detected visually. Two road-killed birds collected in Puna in June 1993, and four burrows located in Puulena Crater after the 1994 breeding season, provided additional evidence of breeding.

Hawaii↗

USGS2014

Importance of reservoir tributaries to spawning of migratory fish in the upper Paraná River

Regulation of rivers by dams transforms previously lotic reaches above the dam into lentic ones and limits or prevents longitudinal connectivity, which impairs access to suitable habitats for the reproduction of many migratory fish species. Frequently, unregulated tributaries can provide important habitat heterogeneity to a regulated river and may mitigate the influence of impoundments on the mainstem river. We evaluated the importance of tributaries to spawning of migratory fish species over three spawning seasons, by comparing several abiotic conditions and larval fish distributions in four rivers that are tributaries to an impounded reach of the Upper Parana River, Brazil. Our study confirmed reproduction of at least 8 long-distance migrators, likely nine, out of a total of 19 occurring in the Upper Parana River. Total larval densities and percentage species composition differed among tributaries, but the differences were not consistent among spawning seasons and unexpectedly were not strongly related to annual differences in temperature and hydrology. We hypothesize that under present conditions, densities of larvae of migratory species may be better related to efficiency of fish passage facilities than to temperature and hydrology. Our study indicates that adult fish are finding suitable habitat for spawning in tributaries, fish eggs are developing into larvae, and larvae are finding suitable rearing space in lagoons adjacent to the tributaries. Our findings also suggest the need for establishment of protected areas in unregulated and lightly regulated tributaries to preserve essential spawning and nursery habitats.

River Research and Applications↗

USGS1973

Seasonal variation of nitrogen, phosphorus, and chlorophyll a in Lake Michigan and Green Bay, 1965

Total and dissolved phosphorus, nitrate, and chlorophyll a were measured at four stations in northern Lake Michigan (inshore Michigan, offshore Michigan, offshore Wisconsin, and inshore Wisconsin) and one station in southern Green Bay during 16 sampling periods in 1965. The nutrients were measured at depths of 2, 5, and 10 meters and chlorophyll a at 2 meters. In Green Bay total phosphorus (33.7 ppb) was about five times as high and dissolved phosphorus (7.0 ppb) more than twice as high as the averages for the four Lake Michigan stations, but nitrate nitrogen concentration (37.3 ppb) was only about onethird that in the lake. Total and dissolved phosphorus were about 50 percent higher in the inshore Michigan area than in the other three lake areas. Concentration and seasonal trends in nitrates differed relatively little among the four lake stations. Nitrate at all areas and depths sampled decreased to almost nondetectable levels during September. Chlorophyll a was 70 percent higher at the two inshore areas than at the two offshore areas in the lake and was more than four times higher in Green Bay than at any lake area.

Technical Paper↗

USGS2003

Den site activity patterns of adult male and female swift foxes, Vulpes velox, in northwestern Texas

Activity of Swift Foxes ( Vulpes velox ) at den sites was studied in northwestern Texas during pup rearing seasons in 2000 and 2001 to determine role of males in parental care. Twenty-four percent of radio-collared females with a potential to breed successfully raised pups to eight weeks of age. We intensively monitored presence and absence of male and female Swift Foxes at two den sites each year. Females were present >2.6 times more at den sites than males during the pup rearing season. Female and male Swift Foxes largely stayed at dens during diurnal hours and were active away from dens during nocturnal and crepuscular hours. Females and males spent 12.4% and 3.0% more time at dens before pups emerged, than after pups emerged, respectively. Following depredation of one male parent, the female spent 29% less time at the den site. Decrease in time spent at the den by the female following loss of her mate suggested that loss of one parent might severely impact recruitment of Swift Foxes. Our observations indicated that intense Coyote ( Canis latrans ) depredation may severely impact pup-rearing success as well as the parental care within Swift Fox family groups.

Texas↗