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At least 1,135 records · Page 63Linked to original sources

Effect of subalpine canopy removal on snowpack, soil solution, and nutrient export, Fraser Experimental Forest, CO

Research on the effects of vegetation manipulation on snowpack, soil water, and streamwater chemistry and flux has been underway at the Fraser Experimental Forest (FEF), CO, since 1982. Greater than 95% of FEF snowmelt passes through watersheds as subsurface flow where soil processes significantly alter meltwater chemistry. To better understand the mechanisms accounting for annual variation in watershed streamwater ion concentration and flux with snowmelt, we studied subsurface water flow, its ion concentration, and flux in conterminous forested and clear cut plots. Repetitive patterns in subsurface flow and chemistry were apparent. Control plot subsurface flow chemistry had the highest ion concentrations in late winter and fall. When shallow subsurface flow occurred, its Ca 2+ , SO 4 2− , and HCO 3 − concentrations were lower and K + higher than deep flow. The percentage of Ca 2+ , NO 3 − , SO 4 2− , and HCO 3 − flux in shallow depths was less and K + slightly greater than the percentage of total flow. Canopy removal increased precipitation reaching the forest floor by about 40%, increased peak snowpack water equivalent (SWE)>35%, increased the average snowpack Ca 2+ , NO 3 − , and NH 4 + content, reduced the snowpack K + content, and increased the runoff four-fold. Clear cutting doubled the percentage of subsurface flow at shallow depths, and increased K + concentration in shallow subsurface flow and NO 3 − concentrations in both shallow and deep flow. The percentage change in total Ca 2+ , SO 4 2− , and HCO 3 − flux in shallow depths was less than the change in water flux, while that of K + and NO 3 − flux was greater. Relative to the control, in the clear cut the percentage of total Ca 2+ flux at shallow depths increased from 5 to 12%, SO 4 2− 5·4 to 12%, HCO 3 − from 5·6 to 8·7%, K + from 6 to 35%, and NO 3 − from 2·7 to 17%. The increases in Ca 2+ and SO 4 2− flux were proportional to the increase in water flux, the flux of HCO 3 − increased proportionally less than water flux, and NO 3 − and K + were proportionally greater than water flux. Increased subsurface flow accounted for most of the increase in non-limiting nutrient loss. For limiting nutrients, loss of plant uptake and increased shallow subsurface flow accounted for the greater loss. Seasonal ion concentration patterns in streamwater and subsurface flow were similar .

Hydrological Processes↗

Effects of well discharges on hydraulic heads in and spring discharges from the geothermal aquifer system in the Bruneau area, Owyhee County, southwestern Idaho

Demand for ground water in the 600- square-mile Bruneau study area has increased since 1954 because of agricultural development. Declining flow at Indian Bathtub Spring is adversely affecting a unique species of snail that inhabits the spring. The Bruneau study area is underlain by sedimentary and volcanic rocks that form a regional geothermal aquifer. Sedimentary rocks range in thickness from zero in the southern part of the study area to more than 3,000 feet in the northeastern corner. Volcanic rocks underlie the entire study area and extend southward to the Jarbidge Mountains. In the central part of the study area, the volcanic rocks are probably 2,000 to 3,000 feet thick. For purposes of study, the regional geothermal aquifer system was divided into sedimentary- and volcanic-rock aquifers. Ground water flows northward through the volcanic-rock aquifer to the sedimentary- rock aquifer, from areas of recharge along the Jarbidge and Owyhee Mountains into the study area, where it is discharged as spring flow or leaves the study area as underflow. Prior to extensive ground-water development, about 10,100 acre-feet was discharged by springs. Ground-water discharge from wells began in the late 1890's. From the 1890's through 1951, annual discharge was less than 10,000 acre-feet. From 1952 to 1978, annual discharge increased to about 40,600 acre-feet. During 1978-91, well discharge declined from the maximum of 49,900 acre-feet in 1981 to 34,700 acre-feet in 1991. Through 1991, nearly 1,400,000 acre-feet of ground water discharged from wells; about 546,000 acre-feet discharged from 1978 through 1991. Most pumped water is from the volcanic-rock aquifer. Ground-water development since the mid-1890's locally has modified the direction of water movement in both the sedimentary- and volcanic-rock aquifers. In 1989, ground water moved toward four cones of depression created by pumping two in the northern part of the study area are in the sedimentary-rock aquifer, two in the southern part are in the volcanic-rock aquifer. Pumping has caused hydraulic heads in the volcanic-rock aquifer to decline more than 30 feet in much of the area and at least 70 feet in one well. About 1 mile from Indian Bathtub Spring, the water level in one well declined about 10 feet during 1979-92, or about 0.7 feet per year. Within the past 25 years, discharge from monitored springs along Hot Creek and the Bruneau River has declined, most notably from Indian Bathtub Spring. Discharge from Indian Bathtub Spring in 1964 was about 2,400 gallons per minute, and by the summer of 1989, discharge was zero. Discharge began to decline in the mid-1960's when the rate of increase in pumpage accelerated. In contrast, discharge from Pence Hot Spring has ranged from about 700 gallons per minute to about 1,100 gallons per minute. Changes in discharge from monitored springs corresponded with changes in hydraulic head, which fluctuates seasonally, and are substantially less in late summer than in the spring. A hydraulic head/spring discharge relation was developed for two sites at Indian Bathtub Spring and a nearby test hole. The relation for Indian Bathtub Spring indicated that a spring discharge of 2,400 gallons per minute would relate to a hydraulic head of about 2,708 feet at the spring, which is about 34 feet higher than the head at zero spring discharge.

Idaho↗

Assessment of runoff volume reduction associated with soil amendments added to portions of highway median-strip catchments in Ohio, 2018–20

The U.S. Geological Survey installed 10 rain gages and 12 calibrated H-flumes to measure rainfall and runoff volumes at 10 locations in Ohio Department of Transportation highway median-strip catchments. Data were collected to facilitate comparisons of rainfall and runoff volumes at study sites before and after stormwater best management practices (BMPs) were installed and between sites with different BMPs. The BMP treatments comprised removing the top layer of the existing soil, rototilling the remaining soil to a 6-inch depth, mixing the soils with one of two soil amendments (compost with sand or shale) at one of two thicknesses (4 inches or 6 inches), topping with a compost blanket, seeding, and installing erosion control matting. The overall treatment used at a given study site is referred to as “BMP.” At two locations where soil amendments were installed, a second “control” site was installed to measure runoff from an adjacent catchment in the same median strip where no soil amendment was installed. This no-treatment option (no soil amendment) was considered its own class of BMP. Rainfall and runoff data were collected during periods when air temperatures were above freezing (including all months except January, February, and parts of December and March) from 2018 to 2020. The data collection period for each study site was divided into “pre-BMP” and “post-BMP” periods. Equipment to measure rainfall and runoff was installed and data were collected from April to December 2018 before installation of soil amendments (the pre-BMP period). The post-BMP period started between April and May of 2019 at the first measured rainfall after soil amendments were installed. Rainfall and runoff monitoring continued through September 2020. For control sites, the post-BMP periods were assigned to start with the first measured rainfall in the 2019 data collection season. A rainfall-runoff “event” was defined as beginning at the time of the first measured rainfall and ending when rainfall and runoff (if any) ceased and remained ceased for at least 3 hours. A value referred to as “event runoff percentage,” defined as the total volume of runoff during an event expressed as a percentage of the total volume of rainfall falling over the catchment, was computed for each event. The distribution of rainfall totals associated with events was similar between the pre-BMP and post-BMP periods; however, there were appreciable between-site differences in the distribution of event runoff percentages during the pre-BMP and post-BMP periods. Empirical distribution function (EDF) tests were performed with and without data from events that resulted in no runoff to determine whether the distribution of event runoff percentages changed from the pre-BMP period to the post-BMP period. The null hypothesis that the EDFs of event runoff percentages were equal in the pre-BMP and post-BMP periods was rejected ( α =0.05) in at least one of the two tests for four sites (one site with a shale amendment and three sites with sand amendments). Mean event runoff percentages at each of those four sites decreased from the pre-BMP period to the post-BMP period. The null hypothesis that the EDFs of event runoff percentages were equal was not rejected for the other six sites’ draining catchments with soil amendments or the two control sites. EDF tests performed on event rainfall totals indicated no statistically significant changes between the pre-BMP and post-BMP period distributions for any of the sites. Double-mass analyses of cumulative runoff were performed for two pairs of closely spaced sites (each pair located in a common median strip): one site in each pair drained a catchment where soil amendments were installed, and the other (a control) drained a catchment without soil amendments. Those double-mass analyses indicated a small reduction in runoff from the pre-BMP to post-BMP period at the site whose catchment received the sand and compost amendment, but no perceptible reduction in runoff at the site whose catchment received the shale and compost amendment. Regression analyses indicated that (a) three rainfall factors (event rainfall totals, total rainfall for the previous 7 days, and a cross product of the factors) and the intercept term were the four most important factors explaining event runoff percentages, (b) the effect of amendment type on event runoff percentage was small in comparison to the rainfall and intercept terms, (c) event runoff percentages tended to be lower for sites with shale amendments than sites with sand amendments; however, event runoff percentages tended to be lower for control sites than for sites with shale or sand amendments, and (d) event runoff percentages increased with increasing amendment thickness. The counterintuitive results that event runoff percentages increased with increasing amendment thickness and that control sites tended to have lower event runoff percentages than sites draining soil-amended catchments likely reflects unmeasured factors that existed at the sites before BMPs were installed rather than the effect of the BMP treatments. Although not definitive, some support for the conclusion that the sand amendment was generally more effective at reducing runoff than the shale amendment was provided by results from the EDF tests, double-mass analyses, and runoff statistics.

Ohio↗

Evaluation of blood and muscle tissues for molecular detection and characterization of hematozoa infections in northern pintails ( Anas acuta ) wintering in California

Information on the molecular detection of hematozoa from different tissue types and multiple years would be useful to inform sample collection efforts and interpret results of meta-analyses or investigations spanning multiple seasons. In this study, we tested blood and muscle tissue collected from northern pintails ( Anas acuta ) during autumn and winter of different years to evaluate prevalence and genetic diversity of Leucocytozoon , Haemoproteus , and Plasmodium infections in this abundant waterfowl species of the Central Valley of California. We first compared results for paired blood and wing muscle samples to assess the utility of different tissue types for molecular investigations of haemosporidian parasites. Second, we explored inter-annual variability of hematozoa infection in Central Valley northern pintails and investigated possible effects of age, sex, and sub-region of sample collection on estimated parasite detection probability and prevalence. We found limited evidence for differences between tissue types in detection probability and prevalence of Leucocytozoon , Haemoproteus , and Plasmodium parasites, which supports the utility of both sample types for obtaining information on hematozoan infections. However, we detected 11 haemosporidian mtDNA cyt b haplotypes in blood samples vs. six in wing muscle tissue collected during the same sample year suggesting an advantage to using blood samples for investigations of genetic diversity. Estimated prevalence of Leucocytozoon parasites was greater during 2006–2007 as compared to 2011–2012 and four unique haemosporidian mtDNA cyt b haplotypes were detected in the former sample year but not in the latter. Seven of 15 mtDNA cyt b haplotypes detected in northern pintails had 100% identity with previously reported hematozoa lineages detected in waterfowl ( Haemoproteus and Leucocytozoon ) or other avian taxa ( Plasmodium ) providing support for lack of host specificity for some parasite lineages.

California↗

Coastal change from Hurricane Sandy and the 2012-13 winter storm season: Fire Island, New York

The U.S. Geological Survey (USGS) mounted a substantial effort in response to Hurricane Sandy including an assessment of the morphological impacts to the beach and dune system at Fire Island, New York. Field surveys of the beach and dunes collected just prior to and after landfall were used to quantify change in several focus areas. In order to quantify morphologic change along the length of the island, pre-storm (May 2012) and post-storm (November 2012) lidar and aerial photography were used to assess changes to the shoreline and beach, and to measure volumetric changes. The extent and thicknesses of overwash deposits were mapped in the field, and measurements were used to determine volume, distribution, and characteristics of the deposits. The beaches and dunes on Fire Island were severely eroded during Hurricane Sandy, and the island breached in three locations on the eastern segment of the island. Landward shift of the upper portion of the beach averaged 19.7 meters (m) but varied substantially along the coast. Shoreline change was also highly variable, but the shoreline prograded during the storm by an average of 11.4 m, due to the deposition of material eroded from the upper beach and dunes onto the lower portion of the beach. The beaches and dunes lost 54.4 percent of their pre-storm volume, and the dunes experienced overwash along 46.6 percent of the island. The inland overwash deposits account for 14 percent of the volume lost from the beaches and dunes, indicating that the majority of material was moved offshore. In the winter months following Hurricane Sandy, seven storm events with significant wave heights greater than four m were recorded at a wave buoy 30 nautical miles south of Fire Island. Monthly shoreline and profile surveys indicate that the beach continued to erode dramatically. The shoreline, which exhibited a progradational trend immediately after Sandy, eroded an average of 21.4 m between November 2012 and mid-March 2013, with a maximum landward shift of nearly 60 m. By March 2013 the elevation of the beach in the majority of the surveyed profiles was lowered below the mean high water level (0.46 m), and the beach lost an additional 18.9 percent of its remaining volume. In the final time period of the field surveys (March to April 2013), the beach began to show signs of rapid recovery, and in 90 percent of the profiles, the volume of the beach in April 2013 was similar to the volume measured immediately after Hurricane Sandy. Overall, Hurricane Sandy profoundly impacted the morphology of Fire Island and resulted in an extremely low elevation, low relief configuration that has left the barrier island vulnerable to future storms. The coastal system subsequently began to show signs of recovery, and although the beach is likely to experience continued recovery in the form of volume gains, the dunes will take years to rebuild. Events such as Sandy result in a coastal environment that is a more vulnerable to future storm impacts, but they are an important natural process of barrier islands that allow these systems to evolve in response to sea-level rise.

New York↗

Evolving infrasound detections from Bogoslof volcano, Alaska: Insights from atmospheric propagation modeling

Bogoslof volcano, a back-arc volcano in Alaska’s Aleutian arc, began an eruptive sequence in mid-December 2016 that ended in late August 2017, with 70 individual eruptive episodes. Because there were no local seismic or infrasound stations on the island, the Alaska Volcano Observatory (AVO) relied on distant geophysical networks and remote sensing techniques to assess activity during the eruption. AVO maintains six infrasound arrays to monitor activity along the Aleutian arc: Adak, the Island of Four Mountains, Okmok, Akutan, Sand Point, and Dillingham. Eruption detection at infrasound arrays is subject to local as well as mesoscale meteorological conditions that vary greatly over both short and long timescales. Infrasound detections from the array nearest to Bogoslof (Okmok), with a latency of about 3 min, played a crucial role in monitoring activity during the eruption. Despite the relative proximity of the Okmok array to Bogoslof (60 km), infrasound detections were not uniformly observed with only about two-thirds of the events successfully detected. The farthest array at Dillingham (816 km) detected approximately half of the explosive events, with all other arrays detecting less than half of the events. We compare observations with infrasound propagation model predictions, using both normal mode and parabolic equation forward models, to interpret the variation in detections of the 70 explosive events across the AVO infrasound network. The forward models utilize the newly created, publicly available AVO-G2S atmospheric reconstruction using numerical weather predictions data for the lower atmosphere, coupled with upper atmosphere empirical models of wind speeds and temperature. We find that long-range detections (> 100 km) of Bogoslof events are largely aligned with seasonal variability in favorable propagation conditions, while regional detections (< 100 km) are less consistent with propagation modeling. Understanding the output of numerical models in comparison to past observations will facilitate their use in future operational settings for AVO and other observatories.

Alaska↗

Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California—2020 Annual Report

Executive Summary Surveys for the endangered Southwestern Willow Flycatcher ( Empidonax traillii extimus ) were done at Marine Corps Base Camp Pendleton (MCBCP or “Base”), California, between May 4 and July 31, 2020. All of MCBCP’s historically occupied riparian habitat (core survey area) was surveyed for flycatchers in 2020. Additionally, one-fifth of the unoccupied riparian habitat (non-core survey area) was surveyed for flycatchers. Thirteen transient Willow Flycatchers of unknown subspecies were observed on four of the seven drainages surveyed in 2020. No Willow Flycatchers were detected at Fallbrook Creek, Pilgrim Creek, or San Mateo Creek. Transients occurred in a range of habitat types, including mixed willow ( Salix spp.) riparian, riparian scrub, willow-sycamore ( Platanus racemosa ) or willow-cottonwood ( Populus fremontii ) dominated riparian vegetation, and upland scrub. Exotic vegetation, primarily poison hemlock ( Conium maculatum ), was present in most flycatcher locations. The resident population of Southwestern Willow Flycatchers on MCBCP declined 33 percent from three individuals in 2019 to two individuals in 2020. In 2020, the resident Southwestern Willow Flycatcher population on Base consisted of one male and one female. No single males or non-territorial floaters were observed in 2020. Overall, one territory was established consisting of one monogamous pair. Resident flycatchers were restricted to the Santa Margarita River, and distribution was limited to the Pueblitos breeding area. All resident flycatchers were located in mixed willow riparian habitat. Nesting was initiated in late May and continued into early August. Three nesting attempts were documented, of which 33 percent (1/3) were successful. Predation and substrate failure accounted for the two nest failures. Two fledglings were produced, yielding a seasonal productivity of two young/pair. No instances of Brown-headed Cowbird ( Molothrus ater ) parasitism were observed. Flycatchers placed nests in two plant species: native sandbar willow ( Salix exigua ) and exotic poison hemlock. One hundred percent of resident birds that were present at MCBCP in 2020 were banded in previous years; no unbanded birds were detected. Of the three uniquely banded adult flycatchers present during the 2019 breeding season, 100 percent (1/1) of males and 50 percent (1/2) of females returned to MCBCP in 2020, and both banded flycatchers returned to the same breeding area they occupied in 2019. None of the seven nestlings banded in 2019 returned to MCBCP in 2020, and none were detected off Base. Six nestlings from two nests were banded in 2020; only two survived to fledging. From 2000 to 2020, overall adult survival of Southwestern Willow Flycatchers on MCBCP was 60 percent, while first-year survival was 20 percent. A conspecific attraction study initiated on Base in 2018 and repeated annually through 2020 found that 100 percent of breeding flycatchers detected in 2020 settled close to automated playback units.

California↗

Environmental drivers of demography and potential factors limiting the recovery of an endangered marine top predator

Understanding what drives changes in wildlife demography is fundamental to the conservation and management of depleted or declining populations, though making inference about the intrinsic and extrinsic factors that influence survival and reproduction remains challenging. Here we use mark–resight data from 2000 to 2018 to examine the effects of environmental variability on age-specific survival and natality for the endangered western distinct population segment (wDPS) of Steller sea lions ( Eumetopias jubatus ) in Alaska, USA. Though this population has been studied extensively over the last four decades, the causes of divergent abundance trends that have been observed across the wDPS range remain unknown. We developed a Bayesian multievent mark–resight model that accounts for female reproductive state uncertainty. Annual survival probabilities for male pups (0.44; 0.36–0.53), female yearlings (0.63; 0.49–0.73), and male yearlings (0.62; 0.51–0.71) born in the western portion of the wDPS range, estimated here for the first time, were lower than those in the eastern portion of the wDPS range, estimated as: male pups (0.69; 0.65–0.74), female yearlings (0.76; 0.71–0.81), and male yearlings (0.71; 0.65–0.78). There was a higher proportion of young female breeders in the western portion of the range, but overall natality was lower (0.69; 0.47–0.96) than in the eastern portion of the range (0.80; 0.74–0.84). Additionally, pup mass had a positive effect on pup survival in the eastern portion of the range and a negative effect in the western portion of the range, potentially due to earlier weaning of heavier pups. Local- and basin-scale oceanographic features such as the Aleutian Low, the Arctic Oscillation Index, the North Pacific Gyre Oscillation, chlorophyll concentration, upwelling, and wind in certain seasons were correlated with vital rates. However, drawing strong inferences from these correlations is challenging given that relationships between ocean conditions and an adaptive top predator in a dynamic ecosystem are exceedingly complex. This study provides the first demographic rate estimates for the western portion of the range where abundance estimates continue to decline. These results will advance efforts to identify factors driving regionally divergent abundance trends, with implications for population-level responses to future climate variability.

Alaska↗

Hydrology and chemistry of floodwaters in the Yolo Bypass, Sacramento River system, California, during 2000

Discharges to and floodwaters in the Yolo Bypass were sampled during winter and spring, 2000. The primary purpose of the study was to link changes in water quality in the Yolo Bypass to inflows from the Sacramento River (over Fremont Weir) and from four local streams that discharge to the west side of the floodplain. Specific conductance, chloride, sulfate, dissolved inorganic nutrients, dissolved organic carbon, particulate carbon and nitrogen, suspended particulate matter (mass), and selected dissolved metals were measured in most of the samples. When the Sacramento River was spilling over Fremont Weir, the water chemistry in the Yolo Bypass was very similar to that in the river except along the western margin of the floodplain where influences of local stream inflow were evident. When flow over Fremont Weir stopped, floodwaters drained from the Yolo Bypass, and the local streams were the major discharges as the floodwaters receded eventually to the perennial channel along the eastern margin of the floodplain. After the initial draining of the floodplain, chemical concentrations at sites along the perennial channel showed strong influences of inflows from Cache Creek and Ridge Cut, which are sources of nutrients and contaminants that are potentially hazardous to wildlife. Runoff from spring storms increased flow in the perennial channel and flushed accumulated nutrients and organic matter to the tidal river. Releases of freshwater to the perennial channel might be beneficial in maintaining habitat quality for aquatic species during the dry seasons.

California↗

Upland duck nesting related to land use and predator reduction

Duck nesting was studied during 1971 in north-central South Dakota under four conditions: in idle, five or six year old fields of domestic grass-legume mixtures in an area where predators including the red fox ( Vulpes fulva ), raccoon ( Procyon lotor ), striped skunk ( Mephitis mephitis ), and badger ( Taxidea taxus ) were (1) reduced and (2) not reduced. Nesting was also studied in tracts of active agricultural land (primarily croplands and pastures) where predators were (3) reduced, and (4) not reduced. Under condition (1), 260 nests were found on 0.87 km 2 (299 nests/km 2 ), eggs hatched in 92 percent of the nests and production was 22.0 ducklings/hectare. Under condition (2), 187 nests were found on 2.22 km 2 (84 nests/km 2 ), nest success was 68 percent and 4.7 ducklings/hectare were produced. On active agricultural land subject to predator reduction (condition 3), 64 nests were found on 5.14 km 2 (12 nests/km 2 ). Eggs in 85 percent of the nests hatched and production was 0.7 duckling/hectare. On active agricultural land not subject to predator reduction (condition 4), 58 nests were found on 4.01 km 2 (14 nests/km 2 ), nest success was 51 percent and 0.5 duckling/hectare was produced. Idle, 16 to 65-hectare (40 to 160-acre) stands of cool-season, introduced grasses in combination with legumes produced maximum numbers of upland nesting ducks.

South Dakota↗

Hydrologic and water-quality conditions in the Kansas River, northeast Kansas, November 2001–August 2002, and simulation of ammonia assimilative capacity and bacteria transport during low flow

Large concentrations of ammonia and densities of bacteria have been detected in reaches of the Kansas River in northeast Kansas during low streamflow conditions, prompting the Kansas Department of Health and Environment (KDHE) to list these reaches as water-quality limited with respect to ammonia and fecal coliform bacteria. Sources for ammonia and bacteria in the watershed consist of wastewater-treatment facilities (WWTFs) and agricultural and urban runoff. The U.S. Geological Survey (USGS), in cooperation with KDHE, conducted an investigation of the Kansas River to characterize hydrologic and water-quality conditions and to simulate ammonia assimilative capacity and bacteria transport during low streamflow. This report characterizes the water-quality conditions, documents the calibration of a two-dimensional water-quality model, and presents results of hypothetical simulations of existing and future WWTFs discharging to the Kansas River during low streamflow. Water samples were collected during low streamflow conditions at 50 sampling sites along and near the Kansas River between Wamego and Kansas City, Kansas, during three synoptic surveys conducted between November 2001 and August 2002. The analytical results from these samples indicated that ammonia and other nutrient concentrations and fecal coliform bacteria densities increased in the Kansas River from Wamego to Kansas City. Point sources were the primary contributors of ammonia and fecal coliform bacteria during low-flow conditions. Generally, ammonia concentrations in the Kansas River were largest at sampling sites just downstream from WWTFs. Overall, ammonia concentrations in the Kansas River, tributaries, and WWTF effluent were larger in the winter than during the summer. None of the main-stem sample concentrations exceeded the State of Kansas pH- and temperature-dependent chronic aquatic-life criteria for ammonia during the sampling periods. Other nutrients, such as total nitrogen and total phosphorus, indicated a similar, but less variable, spatial pattern along the main stem of the Kansas River, with concentrations increasing slightly downstream from major WWTFs. The temporal variance defined by the results of synoptic survey III (July 22&ndash;August 8, 2002) indicated that ammonia concentrations in the Kansas River sometimes varied daily by as much as 155 percent at a single site. Samples analyzed for densities of fecal coliform bacteria illustrated a seasonal, spatial, and temporal pattern slightly different from that of nutrients. Overall, the bacteria densities measured during the summer were larger than the densities measured in the winter. The only fecal coliform bacteria density to exceed the former State water-quality, single-sample criteria of 2,000 col/100 mL (colonies per 100 milliliters of water) was measured at 4,000 col/100 mL during synoptic III (summer 2002) on the main stem of the Kansas River at Kansas City. Temporal variability measured during synoptic survey III indicated up to a 263-percent difference in bacteria density over a 12-day period. Instantaneous loads of ammonia and bacteria were computed to determine primary inputs to the Kansas River and ammonia and bacteria decay rates in the river. The Oakland WWTF in Topeka was the largest contributor of both ammonia and bacteria on the basis of samples collected during the three synoptic surveys, except for fecal coliform bacteria collected during synoptic survey III when the DeSoto WWTF was discharging the largest concentration of bacteria. The ammonia assimilative process was about twice as effective during the summer synoptic survey than it was during the winter survey. Decay of fecal coliform bacteria density was less evident and appeared to have little seasonal effect on the basis of data collected for this report. The summer low-streamflow water-quality conditions were suitable for nitrification, algae that consume ammonia, and consequently, decaying organic matter that consume oxygen. The consumption of dissolved oxygen due to nitrification and decaying algae contributed to three measurements of dissolved oxygen that were less than the State of Kansas aquatic-life-support use criteria of 5.0 milligrams per liter. CE&ndash;QUAL&ndash;W2, a two-dimensional, hydrodynamic and water-quality model, was used to simulate ammonia and bacteria transport in the Kansas River from Topeka to Kansas City. The model was calibrated and verified using data from the three synoptic surveys. The calibrated model successfully simulated the hydrodynamics, water temperature, dissolved oxygen, ammonia, and fecal coliform bacteria in the Kansas River. Simulated in-stream ammonia concentrations were compared to measured concentrations upstream to downstream along the Kansas River. The simulated in-stream ammonia concentrations mostly overestimated the measured values for both winter and summer, with a few exceptions. Comparisons between measured and simulated in-stream ammonia concentrations indicated ammonia assimilation was simulated more accurately in the summer than during the winter. Four hypothetical simulations of varied effluent discharges from existing WWTFs and addition of a proposed WWTF near DeSoto were simulated to better understand future water-quality conditions in the Kansas River. Results indicated that ammonia and dissolved-oxygen concentrations in the Kansas River will decrease from the conditions observed during synoptic surveys II (February 25 through March 1, 2002) and III (July 22 through August 8, 2002) except near the proposed WWTF where concentrations of ammonia would be near or exceed criteria for waterborne species. Effects of the proposed WWTF on dissolved oxygen would result in concentrations less than the State of Kansas aquatic-life-support use criteria of 5.0 milligrams per liter for 1 to 2 miles downstream from either of the proposed sites.

Kansas↗

Avian comparisons between Kingman and Kenilworth Marshes: Final report 2001-2004

In 2001 avi-fauna was added as a parameter to be monitored as an indicator of the status and relative success of the two reconstructed freshwater tidal wetlands residing in the Anacostia River estuary in Washington, D.C. at that time. They were Kenilworth Marsh which was reconstructed in 1993 and Kingman Marsh seven years later in 2000. Other studies were already underway looking at vegetation, seeds, soils and contaminants. Even though these new wetlands were relatively small, together about 70 acres, it was felt this might be sufficient area to sustain and attract birds to the habitat. Birds have been used elsewhere as wetland indicators and we hoped they could prove useful here especially in terms of numbers and species richness. The study was conducted for almost four years (2001-2004) and was designed to ascertain if the recently reconstructed Kingman Marsh evolved similarly with respect to the avi fauna as Kenilworth which had the seven year head start. Twelve observation points were established, six at each marsh, which were to be used weekly so as to alternate the high and low tidal regimes and the observation start times. Additional notations were recorded for species while walking between observation points. The course of the study became interrupted with the incursion of resident Canada geese particularly upon the Kingman Marsh site. Goose herbivory coupled with lowered sediment elevations reduced vegetation cover at Kingman Marsh to less than one-third its intended scope while Kenilworth was barely affected. The result was actually much less impact on the bird populations than on the vegetation. In fact the additional mudflat area at Kingman may have actually helped attract some birds. Together 177 species were identified at the marshes comprising 14 taxonomic orders and 16 families, 137 species at Kingman and 164 at Kenilworth. However, Kingman actually attracted more birds than Kenilworth, whether or not Canada Geese were included. At both wetlands winter usage was significantly greater than at other seasons; however, there were more species in the spring and summer. Three functional guilds were looked at in particular: wetland users, freshwater marsh users and mudflat/shore users. Mudflat users were greatest during the winter while marsh users were greater in the fall. Additional useful data was collected relative to the Canada Goose impacts. The interruption in marsh evolution at Kingman driven by the goose herbivory precluded the opportunity to use the avifauna as an indicator of marsh restoration success.

Book↗

Trends in the quality of water in New Jersey streams, water years 1998-2007

Trends were determined in flow-adjusted values of selected water-quality characteristics measured year-round during water years 1998-2007 (October 1, 1997, through September 30, 2007) at 70 stations on New Jersey streams. Water-quality characteristics included in the analysis are dissolved oxygen, pH, total dissolved solids, total phosphorus, total organic nitrogen plus ammonia, and dissolved nitrate plus nitrite. In addition, trend tests also were conducted on measurements of dissolved oxygen made only during the growing season, April to September. Nearly all the water-quality data analyzed were collected by the New Jersey Department of Environmental Protection and the U.S. Geological Survey as part of the New Jersey Department of Environmental Protection Ambient Surface-Water Quality Monitoring Network. Monotonic trends in flow-adjusted values of water quality were determined by use of procedures in the ESTREND computer program. A 0.05 level of significance was selected to indicate a trend. Results of tests were not reported if there were an insufficient number of measurements or insufficient number of detected concentrations, or if the results of the tests were affected by a change in data-collection methods. Trends in values of dissolved oxygen, pH, and total dissolved solids were identified using the Seasonal Kendall test. Trends or no trends in year-round concentrations of dissolved oxygen were determined for 66 stations; decreases at 4 stations and increases at 0 stations were identified. Trends or no trends in growing-season concentrations of dissolved oxygen were determined for 65 stations; decreases at 4 stations and increases at 4 stations were identified. Tests of pH values determined trends or no trends at 26 stations; decreases at 2 stations and increases at 3 stations were identified. Trends or no trends in total dissolved solids were reported for all 70 stations; decreases at 0 stations and increases at 24 stations were identified. Trends in total phosphorus, total organic nitrogen plus ammonia, and dissolved nitrate plus nitrite were identified by use of Tobit regression. Two sets of trend tests were conducted-one set with all measurements and a second set with all measurements except the most extreme outlier if one could be identified. The result of the test with all measurements is reported if the results of the two tests are equivalent. The result of the test without the outlier is reported if the results of the two tests are not equivalent. Trends or no trends in total phosphorus were determined for 69 stations. Decreases at 12 stations and increases at 5 stations were identified. Of the five stations on the Delaware River included in this study, decreases in concentration were identified at four. Trends or no trends in total organic nitrogen plus ammonia were determined for 69 stations. Decreases and increases in concentrations were identified at six and nine stations, respectively. Trends or no trends in dissolved nitrate plus nitrite were determined for 66 stations. Decreases and increases in concentration were identified at 4 and 19 stations, respectively.

Scientific Investigations Report↗

Occurrence and distribution of pesticides in surface waters of the Hood River basin, Oregon, 1999-2009

The U.S. Geological Survey analyzed pesticide and trace-element concentration data from the Hood River basin collected by the Oregon Department of Environmental Quality (ODEQ) from 1999 through 2009 to determine the distribution and concentrations of pesticides in the basin's surface waters. Instream concentrations were compared to (1) national and State water-quality standards established to protect aquatic organisms and (2) concentrations that cause sublethal or lethal effects in order to assess their potential to adversely affect the health of salmonids and their prey organisms. Three salmonid species native to the basin are listed as "threatened" under the U.S. Endangered Species Act: bull trout, steelhead, and Chinook salmon. A subset of 16 sites was sampled every year by the ODEQ for pesticides, with sample collection targeted to months of peak pesticide use in orchards (March-June and September). Ten pesticides and four pesticide degradation products were analyzed from 1999 through 2008; 100 were analyzed in 2009. Nineteen pesticides were detected: 11 insecticides, 6 herbicides, and 2 fungicides. Two of four insecticide degradation products were detected. All five detected organophosphate insecticides and the one detected organochlorine insecticide were present at concentrations exceeding water-quality standards, sublethal effects thresholds, or acute toxicity values in one or more samples. The frequency of organophosphate detection in the basin decreased during the period of record; however, changes in sampling schedule and laboratory reporting limits hindered clear analysis of detection frequency trends. Detected herbicide and fungicide concentrations were less than water-quality standards, sublethal effects thresholds, or acute toxicity values. Simazine, the most frequently detected pesticide, was the only herbicide detected at concentrations within an order of magnitude (factor of 10) of concentrations that impact salmonid olfaction. Some detected pesticides are of concern, not for their toxicity alone, but for their ability to potentiate the harmful impacts of other pesticides, particularly organophosphates, on salmonids or their prey. Many samples contained mixtures of pesticides, but the effects to salmonids of relevant mixtures at environmentally realistic concentrations for the basin are unknown. Trace-element concentration data, although limited, indicate that eight trace elements are also of concern for their potential to harm salmonid health. The dataset is limited with regard to the spatial and seasonal distribution of pesticides and trace elements in all salmonid-bearing streams, the presence of particle-bound pesticides, and the presence of several unmonitored pesticides known to be used in the basin.

Oregon↗

Hydrogeology and simulation of groundwater flow in Columbia County, Wisconsin

This report describes the regional hydrogeology and groundwater resources of Columbia County, Wisconsin, and documents a regional groundwater flow model developed for the county. Regional hydrostratigraphic units include the unlithified aquifer, the upper bedrock aquifer, and the Elk Mound aquifer. The unlithified aquifer consists of deposits that range in composition from sand and gravel outwash and stream deposits to silty, sandy till. This aquifer is less than 25 ft thick in much of eastern Columbia County, but consists of permeable sand and gravel extending to over 250 ft in depth in the Wisconsin River valley bottom. The upper bedrock aquifer consists of Ordovician and upper Cambrian sedimentary formations, including sandstone, siltstone and dolomitic strata. The upper bedrock aquifer underlies the unlithified aquifer in eastern portions of the County, but is absent to the west, where these formations are largely eroded. The contact between the Tunnel City Group and Wonewoc Formation (Top of Elk Mound Group) forms the base of the upper bedrock aquifer. Bedding plane fractures are common to this aquifer, although only a portion of the observed fractures appear to be hydraulically active. The upper bedrock aquifer is a significant source of groundwater at a regional scale. Measurements of hydraulic head showed a difference of several feet across the bottom of this aquifer to the underlying Wonewoc sandstone, indicating that the basal facies of the Tunnel City Group functions as an aquitard separating the upper bedrock aquifer from the Elk Mound aquifer. Conditions vary considerably within this aquifer, depending on the local lithostratigraphy. For example, where present, the St. Lawrence Fm. and fine-grained intervals of the Tunnel City Group may be locally-extensive aquitards. The Elk Mound aquifer consists of Cambrian sandstone of the Wonewoc, Eau Claire, and Mount Simon Formations. It is thin to absent in several locations but ranges up to 600 ft in thickness over much of southern Columbia County. The variation in thickness is due in large part to the irregular topography of the underlying Precambrian crystalline rock, which generally serves as the base of the groundwater system. In neighboring counties, a fine-grained facies within the Eau Claire Fm. acts as a regionally extensive aquitard, referred to as the Eau Claire aquitard. Much of the data collected and compiled for this study suggest that shale or dolomite within the Eau Claire Fm., which is the equivalent of the Eau Claire aquitard, occurs only within southwestern Columbia County. There is little to no evidence of the Eau Claire aquitard over most of the county. Where the dolomite and shale are absent, the Elk Mound aquifer is relatively homogenous and does not include a mappable aquitard. A three-dimensional steady-state flow model presented here represents long-term, average conditions in the regional groundwater system since about 1970. The model was constructed with the U.S. Geological Survey’s MODFLOW-NWT code; it has six layers with a uniform grid of 300 ft x 300 ft cells. Layers 1 and 2 simulate the unlithified aquifer and layer 3 represents the upper bedrock aquifer. The Elk Mound aquifer is simulated by layers 4, 5 and 6, representing the Wonewoc, Eau Claire, and Mount Simon Formations, respectively. The model extends beyond the boundaries of Columbia County to ensure that hydrologic conditions simulated within the County are consistent with regional conditions. Recharge to the groundwater flow model is based on results from a GIS-based soil-water-balance model. Recharge was simulated with the unsaturated zone flow (UZF) package in MODFLOW. This approach is particularly useful for quantifying groundwater discharge to riparian wetlands because UZF tracks recharge that would lead to the simulated water table exceeding the land surface (represented by the top of model layer 1) and reroutes it to nearby stream segments. The model includes pumping from 256 wells, and 178 of these are located within Columbia County. Pumping totaled about 28 million gallons per day (mgd) on average since 1970, with 7.2 mgd of the withdrawal from within the County. Model calibration was performed with the PEST parameter estimation code. Calibration targets included approximately 3,900 head measurements and 91 stream flow measurements. Four vertical-head differences across hydrogeologic units, calculated from data collected during packer testing in wells in Columbia County, were also used in model calibration. Results from the calibrated model provide a groundwater balance for the region. About 83 percent of groundwater originates as recharge to the water table, 12 percent comes from leakage from streams, and about 5 percent of the groundwater flows into the model domain from surrounding areas. About 95 percent of the simulated groundwater discharges to steams and other surface water features, about 3 percent flows across model boundaries to surrounding areas of the groundwater system, and pumping accounts for 2 percent of discharge. Simulated flow paths are relatively local, from recharge in upland areas to discharge in nearby streams and wetlands. The model has many potential applications, including simulation of the effects of existing or proposed high-capacity wells, estimating the zone of contribution for these wells, and understanding relationships between surface water and groundwater. Future refinements to the model, such as incorporating new information about the extent and hydraulic characteristics of the Tunnel City Group, will improve its utility in understanding advective flow between the upper bedrock and Elk Mound aquifers. If seasonal or annual variations in the groundwater system are of interest, this steady-state model could be brought into a transient mode.

Wisconsin↗

Movements of wolves at the northern extreme of the species' range, including during four months of darkness

Information about wolf ( Canis lupus ) movements anywhere near the northern extreme of the species' range in the High Arctic (>75&deg;N latitude) are lacking. There, wolves prey primarily on muskoxen ( Ovibos moschatus ) and must survive 4 months of 24 hr/day winter darkness and temperatures reaching -53 C. The extent to which wolves remain active and prey on muskoxen during the dark period are unknown, for the closest area where information is available about winter wolf movements is >2,250 km south. We studied a pack of &ge;20 wolves on Ellesmere Island, Nunavut, Canada (80&deg;N latitude) from July 2009 through mid-April 2010 by collaring a lead wolf with a Global Positioning System (GPS)/Argos radio collar. The collar recorded the wolf's precise locations at 6:00 a.m. and 6:00 p.m. daily and transmitted the locations by satellite to our email. Straight-line distances between consecutive 12-hr locations varied between 0 and 76 km. Mean (SE) linear distance between consecutive locations (n = 554) was 11 (0.5) km. Total minimum distance traveled was 5,979 km, and total area covered was 6,640 km 2 , the largest wolf range reported. The wolf and presumably his pack once made a 263-km (straight-line distance) foray to the southeast during 19&ndash;28 January 2010, returning 29 January to 1 February at an average of 41 km/day straight-line distances between 12-hr locations. This study produced the first detailed movement information about any large mammal in the High Arctic, and the average movements during the dark period did not differ from those afterwards. Wolf movements during the dark period in the highest latitudes match those of the other seasons and generally those of wolves in lower latitudes, and, at least with the gross movements measurable by our methods, the 4-month period without direct sunlight produced little change in movements.

Ellesmere Island;Nunavut↗

Resilience of predators to fishing pressure on coral patch reefs

Numbers and biomass of piscivorous fish and their predation on other fish may often be high in undisturbed coral reef communities. The effects of such predation have sometimes been studied by removal of piscivores (either experimentally or by fishermen). Such perturbations have usually involved removal of large, highly vulnerable, mobile piscivores that are often actively sought in fisheries. The effects of fishing on smaller, demersal, semi-resident piscivores have been little studied. We studied such effects on the fish communities of patch reefs at Midway atoll by experimentally removing major resident, demersal, piscivorous fishes. First, four control reefs and four experimental reefs were selected, their dimensions and habitats mapped, and their visible fish communities censused repeatedly over 1 year. Census of all control and experimental reefs was continued for the following 39 months, during which known piscivores were collected repeatedly by hand spearing. Records were kept of catch and effort to calculate CPUE as an index of predator density. Spearfishing on the experimental reefs removed 2504 piscivorous fish from 12 families and 43 taxa (mostly species). The species richness of the catch did not show an overall change over the duration of the experiment. Spearman rank correlation analysis showed some unexpected positive correlations for density in numbers and biomass of major fished piscivorous groups (especially lizardfish) over the experiment. Only two relatively minor fished piscivorous taxa declined in abundance over the experiment, while the overall abundance of piscivores increased. Visual censuses of fish on the experimental reefs also failed to show reduction of total piscivores over the full experimental period. No significant trend in the abundance of lizardfish censused over the full period was apparent on any of the control reefs. The high resilience of piscivores on these experimental reefs to relatively intense fishing pressure could result from their protracted recruitment seasons, high immigration rates, cryptic habits, or naturally high abundances. A major factor was the high immigration rates of lizardfish, replacing lizardfish and other less mobile piscivores removed from the reefs by spearing. On the fished reefs, the removed lizardfish population replaced itself >20 times during the experiment; other piscivorous taxa replaced themselves only 5 times.

Journal of Experimental Marine Biology and Ecology↗

Role of landscape features in resource selection by female Greater Prairie-chickens within a constrained environment

Greater Prairie-chickens ( Tympanuchus cupido ) historically occupied 20 states within the contiguous United States; however, due to habitat degradation and loss, they are currently found in 11 states, only four of which have a stable population. Kansas supports a relatively large abundance of Greater Prairie-chickens, where the Flint Hills ecoregion historically supported the largest population density of all ecoregions. In the past decade, the Flint Hills population has declined by 75 % to an estimated 8,334 individuals in 2021 from 34,180 individuals in 2015 due to landscape changes and intensification of grassland management practices. The Fort Riley Military Reservation in the northwest portion of the Flint Hills ecoregion is one of a few areas within the ecoregion that does not implement grazing or vast annual burning. The Greater Prairie-chicken population within Fort Riley has remained relatively stable over the past 25 years despite being constrained by surrounding landscape features and development. We analyzed multiple scales of resource selection by 46 female Greater Prairie-chickens during March-April 2019–2021 on Fort Riley to investigate why this population is doing relatively well compared to populations in surrounding areas. We tested landscape feature, vegetation, and burn mosaic variables to evaluate which variables had the greatest influence on resource selection. Landscape features had the greatest influence on resource selection. Females avoided trees within Fort Riley for both breeding season use and nest-site selection at a greater margin than any other study in Kansas. Additionally, fourth-order selection was not evident within this study system, contrary to studies within surrounding areas. Our findings join a growing body of literature that suggests containment of woody encroachment as a high priority for managers to maintain or expand prairie grouse habitat in many different environments. This containment is especially critical on Fort Riley because of its constrained environment, and further woody encroachment could lead to loss of habitat that is inescapable by the Greater Prairie-chicken population on Fort Riley. Spatially-explicit evaluations of habitat availability are increasingly important as more areas within the Greater Prairie-chicken range become constrained by urbanization, agricultural expansion, and intensive management practices.

Kansas↗