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At least 757 records · Page 42Linked to original sources
USGS2020

Identifying life history traits that promote occurrence for four minnow (Leuciscidae) species in intermittent Gulf Coastal Plain streams

- Life history traits of stream fishes partly reflect adaptations to disturbance regimes, which in turn shape assemblage composition via environmental filters. In this study, we focused on life history traits of four morphologically similar leuciscid species in coastal plain streams of southwestern GA that are shifting from historically perennial to intermittent flow. We evaluated differences in reproductive timing, sex ratio, body size at maturity, reproductive investment, and diet, traits hypothesized to influence species persistence in intermittent streams. We first ordinated published species occurrence data for samples of fish communities in perennial and intermittent streams in the study region, and identified four focal taxa as differing in their associations with intermittency. We then periodically sampled individuals of the focal taxa in 14 streams over a year (May 2016-April 2017). We found that for Pteronotropis harperi (Redeye Chub), a species strongly associated with intermittent streams, reproductive timing did not overlap with typical seasonal stream drying. Redeye chub also had the significantly smallest minimum length at maturation and the greatest reproductive investment. Fishes associated with perennial streams (Pteronotropis grandipinnis (Apalachee Shiner) and Notropis petersoni (Coastal Shiner)), or not associated with either stream type (Notropis texanus (Weed Shiner)), had at least a portion of their reproductive timing overlapping with times when streams were likely to dry, and had similar and significantly lower reproductive investment than Redeye Chub. Redeye Chub displayed no shift in diet when streams ceased flowing, while Apalachee Shiner showed decreases in terrestrial prey. Our results suggest that the size at maturity, reproductive timing, and reproductive investment may promote persistence by the Redeye Chub given projections of more frequent and intense periods of stream intermittency.

Gulf Coast↗
USGS2005

Population status of Kittlitz's Murrelet Brachyramphus brevirostris along the southern coast of the Alaska Peninsula

The Kittlitz's murrelet ( Brachyramphus brevirostris ) is a rare seabird that nests in alpine terrain and generally forages near tidewater glaciers during the breeding season. An estimated 95% of the global population breeds in Alaska, with some unknown proportion breeding in the Russian Far East. A global population estimate using bestavailable data in the early 1990s was 20,000 individuals. However, recent survey data from two core areas (Prince William Sound and Glacier Bay) suggest that populations have declined by 75-90% during the past 10-20 years. In response to these declines, a coalition of environmental groups petitioned the USFWS in May 2001 to list the Kittlitz’s murrelet under the Endangered Species Act (ESA), and in 2004 Kittlitz’s Murrelet was declared a candidate species under the ESA. In 2005, BirdLife International classified the species as “critically endangered”. In 2002, we began a three-year project to examine population status and trend of Kittlitz’s Murrelets in areas where distribution and abundance were poorly known. Results from the 2002 field season, focused on the south coast of the Kenai Peninsula, suggested that the local population of Kittlitz’s Murrelets has declined by ca. 74% since 1986, with a current population of ca. 500 individuals. Here we present results from the 2003 field season when we surveyed Kittlitz’s Murrelets along the southern coast of the Alaska Peninsula. This is a large region that encompasses a substantial portion of the known range of the Kittlitz’s Murrelet, yet has never been surveyed rigorously for murrelets or any other non-colonial marine birds. During four weeks of surveys, we established a set of nearshore and offshore transects (over 825 linear kilometers in total) with a stratified sample design, combining random and systematically selected transects. From a total of 123 individuals seen on transects, we estimate a total population of 2265 (95% CI 1165-4405) Kittlitz’s Murrelets along the south coast of the Alaska Peninsula. For comparison, we estimate the population size of the congeneric Marbled Murrelet ( Brachyramphus marmoratus ). We discuss broad-scale murrelet habitat relationships and species comparisons, and present recommendations for management and future work. Other species of marine birds and mammals were also surveyed; summarized information is included as an appendix.

Alaska↗
USGS2004

Pesticides in surface water runoff in south-eastern New York State, USA: Seasonal and stormflow effects on concentrations

Samples from two streams (Kisco River and the Middle Branch of the Croton River) in the Croton Reservoir system in south-eastern New York State, USA were sampled from May 2000 through to February 2001 in order to document the effect of land use, streamflow and seasonal patterns of application on pesticide concentrations in runoff from developed watersheds. Many of the pesticides detected most commonly in this study are generally used in developed areas, and particularly on turfgrass. Pesticide concentrations were generally higher, and the numbers of compounds were generally larger, in samples from the Kisco River than in samples from the Middle Branch, probably because the Kisco River drainage has a greater population density and is more extensively developed. Four pesticides (2,4-D, 2,4-D-methyl, dicamba and metalaxyl) were detected in at least one sample from the Kisco River at a concentration > 1 ??g litre-1, and no pesticides were detected at concentrations >0.4 ??g litre-1 in Middle Branch samples. No human-health-based water-quality standards were exceeded by samples from either site in this study, but samples from the Kisco River contained four insecticides (carbaryl, chlorpyrifos, diazinon and malathion) and one herbicide (2,4-D) in concentrations that exceeded water quality criteria for the protection of aquatic life. The highest concentrations of most compounds occurred during stormflows in both streams in June, September and December, 2000. The lowest concentrations of most compounds at both sites occurred during baseflows from October 2000 through February 2001, even though the concentrations of many compounds increased substantially at the Kisco River site during stormflows in November and December. Detailed data on the variability of pesticide concentrations during stormflows indicate that there may be two sources of pesticides in the Kisco River watershed: (1) elevated concentrations of pesticides during peak flows that occur early in stormflows likely reflect runoff from paved areas, and (2) elevated concentrations during peak flows that occur later in stormflows from areas with lesser amounts of pavement. Data from the Kisco River indicate that the relation between storm discharge and pesticide concentrations varies among compounds, in part because of variation in seasonal application patterns. These variations in the timing of application result in not all stormflows producing increased concentrations of pesticides. Overall, these results indicate the importance of stormflow sampling throughout the year in assessing pesticide late and transport in urbanized, developed areas.

Conference Paper↗
USGS1969

Pre-nesting and nesting behavior of the Swainson's warbler

The Swainson?s Warbler is one of the least known of southern birds. Although fairly common in some parts of its summer range, observations of its breeding biology have been made by very few persons. The present study was conducted mostly at Macon, Georgia; Pendleton Ferry, Arkansas; and Dismal Swamp, Virginia....In central Georgia and east-central Arkansas, Swainson?s Warblers usually arrive on their territories during the first two weeks in April. Territories in several localities ranged in size from 0.3 to 4.8 acres. A color-marked Arkansas male occupied the same territory for at least four months. Hostile encounters between territorial male Swainson?s Warblers usually take place along the boundary of adjacent territories. Paired males were more aggressive than unpaired males. Toward the end of an encounter one of the two males would usually perform a display in which the wing and tail feathers were spread and the tail vibrated. Following boundary encounters males drifted back onto their territories and usually sang unbroken courses of songs for several minutes.....During pre-nesting at Macon, a mated pair spent the day mostly on the ground within 20 feet of each other, often foragin g 3 to 4 feet apart. What may have been a form of courtship display, in which the male flew from a perch down to the female and either pecked her rump or pounced on her, occurred about three times each hour throughout the day. During this period the male sang less than at other times during the breeding season.....First nests are usually built by the first week in May. Although other investigators reported finding nests of this species outside of the defended territory, all nests that I have found were within the territory. The large, bulky nest of this species usually is placed 2-6 feet above the ground. It is built by the female from materials gathered close to the nest site; and takes two or three days to complete.....Three and occasionally four white eggs are laid. The female incubates for 14-15 days. The Cowbird parasitizes nests in some parts of the breeding range of the Swainson?s Warbler.....During incubation the female spends about 78 per cent of daylight time on the nest. Both sexes feed young and clean nest. Young remain in nest from 10-12 days.

The Wilson Bulletin↗
USGS2025

Multispectral red-edge indices accurately estimate nitrogen content in winter cereal cover crops

Winter cover crops reduce erosion and nutrient runoff from agricultural systems. Although cereal cover crops can decrease field nitrate leaching by 50%–95%, the magnitude of this reduction varies within and between fields, making it challenging to monitor the impact of cover crops on nitrate leaching at large spatial extents. Satellite remote sensing using red-edge bands has been shown to effectively estimate crop nitrogen (N) content (kg ha −1 ) in later growth-stage crops with a closed canopy. In this study, we evaluated 15 spectral indices derived from Sentinel-2 imagery to estimate N concentration (%) and content (kg ha −1 ) of cereal cover crops, using 1627 destructive samples collected from 2018 to 2023 in Maryland. Observed N content ranged from 0.1 to 214.7 kg ha −1 , while N concentration ranged from 0.6% to 5.5%. The 15 indices considered were poor predictors of N concentration (adj. R 2 = 0.089, root mean squared error [RMSE] = 0.802%), but were more successful at measuring N content (biomass × N concentration). Delta red-edge (ΔRE) was the best predictor of N content (adj. R 2 = 0.748, RMSE = 13.10 kg ha −1 from cross-validation with 80% train and 20% test splits iterated 100 times) using samples with imagery collected within ±4 days of destructive sampling ( n = 1110). Our findings indicate that longer red-edge wavelengths (783 and 740 nm) are more suited for estimating N content in cereal cover crops compared to shorter red-edge wavelengths, which have been shown to be more sensitive to biomass. Leave-one-year-out cross-validation demonstrated that the relationship between ΔRE and N content was robust across all four cover crop sampling years included in the study (adj. R 2 = 0.700–0.769, RMSE = 10.70–15.40 kg ha −1 ). Regression model performance improved with the addition of multiple predictors, including biomass (estimated from Normalized Difference Vegetation Index), weather variables (adj. R 2 = 0.765, RMSE = 12.37 kg ha −1 ), management variables (species, season, adj. R 2 = 0.772, and RMSE = 12.13 kg ha −1 ), and biophysical variables (height, fractional ground cover, adj. R 2 = 0.818, and RMSE = 10.29 kg ha −1 ). These findings demonstrate the feasibility of quantifying N content in cereal cover crops using a red-edge-based spectral index across large geographic extents and indicate the inclusion of additional predictors, such as weather and management data, improves model accuracy. This work has implications for quantifying reductions in N leaching associated with cover crops, aiding in policymaking and evaluation of conservation programs that impact water bodies such as Chesapeake Bay.

Maryland↗
USGS1994

Determination of atrazine in rainfall and surface water by enzyme immunoassay

Rainwater and surface water from four sites in Germany (Bavaria and Lower Saxony) were analyzed for atrazine by enzyme immunoassay from June 1990 until October 1992. The limit of quantification of the immunoassay was 0.02 μg/L with a middle of the test at 0.2 μg/L. About 60 % of the samples contained measurable amounts of atrazine. Seasonal trends were observed, with the highest concentration in the summer months of up to 4 μg/L for rainwater and up to 15 μg/L for surface waters. The highest concentrations were found in agricultural areas, while in the investigated national parks up to 0.56 μg/L could be detected in rain water. This points to long-range atmospheric transport from agricultural areas to pristine national parks. Samples from forest stands usually showed higher atrazine concentrations than samples from open fields. Deposition rates of 10 – 50 μg/m 2 · yr were observed in the national parks and 10–180 μg/m 2 · yr at the agricultural sites. Comparison of results obtained by enzyme immunoassay and GC/MS showed a good correlation of r = 0.95.

Environmental Science and Pollution Research↗
USGS2014

Climate remains an important driver of post-European vegetation change in the eastern United States

The influence of climate on forest change during the past century in the eastern United States was evaluated in a recent paper (Nowacki & Abrams, 2014 ) that centers on an increase in ‘highly competitive mesophytic hardwoods’ (Nowacki & Abrams, 2008 ) and a concomitant decrease in the more xerophytic Quercus species. Nowacki & Abrams ( 2014 ) concluded that climate change has not contributed significantly to observed changes in forest composition. However, the authors restrict their focus to a single element of climate: increasing temperature since the end of the Little Ice Age ca. 150 years ago. In their study, species were binned into four classifications (e.g., Acer saccharum – ‘cool-adapted’, Acer rubrum – ‘warm-adapted’) based on average annual temperature within each species range in the United States, reducing the multifaceted character of climate into a single, categorical measure. The broad temperature classes not only veil the many biologically relevant aspects of temperature (e.g., seasonal and extreme temperatures) but they may also mask other influences, both climatic (e.g., moisture sensitivity) and nonclimatic (e.g., competition).

Global Change Biology↗
USGS1981

Common tern colonies along the mid-Atlantic coast. I. Nestling chronology

1. Sixteen Common Tern colonies in Rhode Island, New Jersey, Virginia, and North Carolina were studied from May through July 1980 by four investigators. Nests were marked during egg laying and were monitored every 5-7 days until fledging of young. 2. Results from 1980 indicate that ambient temperature differences in the four study areas account for differences in the onset of egg laying with North Carolina and Virginia colonies beginning 12-16 days before New Jersey and Rhode Island birds. Temperature alone, however, does not seem to have a significant effect on either median egg-laying dates or total duration of the season. 3. The low frequency of late-season nesting was not correlated with colony size or success of peak nests in 1980, but renesting (or late nesting) in all study areas was rare because of the benign weather conditions during the spring. Similarly, no significant correlation was found between success of nests and colony size.

Colonial Waterbirds↗
USGS2005

Mortality in the endangered Laysan teal, Anas laysanensis: conservation implications

The Laysan Teal Anas laysanensis is an endangered anatid of the Hawaiian Islands, currently restricted to an emergent atoll, Laysan Island. Laysan Island lacks terrestrial mammalian predators, which permits the examination of mortality rates and causes without the anthropogenic effects of introduced predators. Mass and morophometrics were measured during the colour-marking of 297 Laysan Teal between 1998 and 2001. Intensive mark-resighting and recovery methods were used to estimate adult and juvenile mortality. One hundred and nineteen carcasses were collected on Laysan between 1998 and 2003, and systematic gross and microscopic examinations were undertaken on 63 of these. Causes of mortality were categorised as trauma, emaciation, miscellaneous or undetermined. Annual adult mortality rates were low, 0.05-0.10 (s.e. <0.01), but duckling mortality was much higher, varying from approximately 0.7-0.9 during 1998-2000 and 2003. Body condition of both sexes deteriorates during the breeding season, and most adult mortality (88%) occurred during or post-breeding (May-October). Cause of mortality was determined via necropsy in 22 ducks. Of three adults, one died from bacterial infections, one was egg bound, and one died from botulism concomitant with nematode infestation. Fourteen ducklings died from acute trauma, four from emaciation sometimes associated with nematode infection, and one from bacterial pneumonia Trauma is a significant factor in Laysan duckling mortalities, and elucidating the cause of and preventing such trauma may allow for management measures to enhance duckling survivability. High duckling mortality rates and emaciation also indicate that habitat on Laysan Island may have limited capacity to support broods.

Hawai'i↗
USGS1993

Annual and Spatial Variation of the Kelp Forest Fish Assemblage at San Nicolas Island, California

The kelp forest fishes of San Nicolas Island, California were studied from 1981-1986 to examine the causes of among-site and among-year variation in the fish assemblages. Fish counts and seven physical and biological variables were recorded at six sites around the island every spring and fall. Over the study period, a total of 45 fish species from 18 families were recorded, though members of nive families dominated at all sites. Among-site variation was considereable with two sites on the south side of the island having two to four times as many non-schooling fishes as the other four sites. Three variables, based on stepwise multiple regression techniques, were important predictors of site-specific fish abundance: 1) vertical relief; 2) sand cover and 3) understory algal cover. The total number of fishes varied interannually by a factor of three. Due to recruitment occuring each spring, there was a strong seasonal component to the variation in fish abundance. The extent of seasonal and interannual variaton of fish abundance is an indication of the variable nature of recruitment to this area. Over the 6 yr period, there were three distinct groupings of fish assemblages correspondong to pre- (Fall 1981 - Fall 1982), during spring (Spring 1983 - Spring 1984) and post El Nino (Fall 1984 - Fall 1986) sampling dates. During El Nino sampling period, there was considerable recruitment of southern affinity fish species, increasing both the abundance and diversity of the fish assemblages. Large-scale oceanographic processes, coupled with site-specific features of the reef habitat, produce a moderately diverse, though relatively abundant fish fauna at San Nicolas Island.

California↗
USGS1953

Progress report of southeastern monazite exploration, 1952

Reconnaissance of placer monazite during the field season of 1952 covered 6,600 square miles drained by streams in the western Piedmont of Virginia 5 North Carolina, South Carolina,, and Georgia. Emphasis during this investigation was placed on the area between the Savannah River at the border of South Carolina and Georgia and the Catawba River in North Carolina because it contains most of the placers formerly mined for monaziteo Four other areas along the strike of the monazite-bearing crystalline rocks were also studied, They center around Mt. Airy, N.C., Athens, Ga. Griffin, Ga. and LaGrange, Ga. In the Savannah River Catawba River district, studies indicate that even the highest grade stream deposits of more than 10 million cubic yards of alluvium contain less than 1 pound of monazite per cubic yard. The average grade of the better deposits is about 0 0 5 pound of monazite per cubic yard. Only trace amounts of niobium, tantalum, and tin have been detected in the placers. Tungsten is absent. Locally gold adds a few cents per cubic yard to the value of placer ground. The best deposits range in size from 1 to 5 million cubic yards and contain 1 to 2 pounds of monazite to the cubic yard. Hundreds of placers smaller than 1 million cubic yards exceed 2 pounds of monazite to the cubic yard and locally attain an average of 10 pounds Monazite deposits around Athens, Ga., are similar to the smaller deposits in the central part of the Savannah River - Catawba River district. A few small very low-grade monazite placers were found near Mt. Airy, N.C., Griffin, Ga., and LaGrange Ga., but they are of no economic value. The larger the flood plain and the farther it lies from the source of the stream, the lower is the monazite content of the sediment. Monazite cannot be profitably mined .from the crystalline rocks in the five areas. The alluvial placers are in stream sediments of post-Wisconsin age. Some pre-Wisconsin terrace gravel of small areal extent is exposed but it contains only a small amount of monazite Pre-Wisconsin to early post-Wisconsin colluvial sediments locally contain 2 pounds of monazite to the cubic yard. Mode of presentation of reports covering field work during the seasons of 1951 - 52 is given. No further reconnaissance will be undertaken, in the western monazite belt.

Georgia;North Carolina;South Carolina;Virginia↗
USGS2017

Nitrogen additions affect litter quality and soil biochemical properties in a peatland of Northeast China

Nitrogen (N) is a limiting nutrient in many peatland ecosystems. Enhanced N deposition, a major component of global climate change, affects ecosystem carbon (C) balance and alters soil C storage by changing plant and soil properties. However, the effects of enhanced N deposition on peatland ecosystems are poorly understood. We conducted a two-year N additions field experiment in a peatland dominated by Eriophorum vaginatum in the Da Xing’an Mountains, Northeast China. Four levels of N treatments were applied: (1) CK (no N added), (2) N1 (6 g N m −2 yr −1 ), (3) N2 (12 g N m −2 yr −1 ), and (4) N3 (24 g N m −2 yr −1 ). Plant and soil material was harvested at the end of the second growing season. N additions increased litter N and phosphorus (P) content, as well as β-glucosidase, invertase, and acid-phosphatase activity, but decreased litter C:N and C:P ratios. Litter carbon content remained unchanged. N additions increased available NH 4 + –N and NO 3 − –N as well as total Gram-positive (Gram+), Gram-negative (Gram−), and total bacterial phospholipid fatty acids (PLFA) in shallow soil (0–15 cm depth). An increase in these PLFAs was accompanied by a decrease in soil labile organic C (microbial biomass carbon and dissolved organic carbon), and appeared to accelerate decomposition and reduce the stability of the soil C pool. Invertase and urease activity in shallow soils and acid-phosphatase activity in deep soils (15–30 cm depth) was inhibited by N additions. Together, these findings suggest that an increase in N deposition in peatlands could accelerate litter decomposition and the loss of labile C, as well as alter microbial biomass and function.

Ecological Engineering↗
USGS1989

Postfledging survival of European starlings

We tested the hypotheses that mass at fledging and fledge date within the breeding season affect postfledging survival in European Starlings (Sturnus vulgaris). Nestlings were weighed on day 18 after hatch and tagged with individually identifiable patagial tags. Fledge date was recorded. Marked fledglings were resighted during weekly two—day intensive observation periods for >9 wk postfledging. Postfledging survival and sighting probabilities were estimated for each of four groups (early or late fledging by heavy or light fledging mass). Body mass was related to postfledging survival for birds that fledged early. Results were not clear—cut for relative fledge date, although there was weak evidence that this also influenced survival. Highest survival probability estimates occurred in the EARLY—HEAVY group while the lowest survival estimate occurred in the LATE—NIGHT group. Sighting probabilities differed significantly among groups, emphasizing the need to estimate and compare survival using models which explicitly incorporate sighting probabilities.

Ecology↗
USGS1875

Systematic catalogue of vertebrata of the Eocene of New Mexico, collected in 1874

The present essay completes the determination of the species of vertebrata obtained by the geographical survey under your charge in the Eocene formation of New Mexico during the field-season of 1874. The descriptions which have already appeared in your [George M. Wheeler] report to the Chief of Engineers, as published in the annual report of the latter for 1874, are not now repeated. The total number of mammalia is forty-seven species, of which the present report introduces twenty-four for the first time.

Monograph↗
USGS2012

Assessing the vulnerability of public-supply wells to contamination: Rio Grande aquifer system in Albuquerque, New Mexico

This fact sheet highlights findings from the vulnerability study of a public-supply well in Albuquerque, New Mexico (hereafter referred to as “the study well”). The study well produces about 3,000 gallons of water per minute from the Rio Grande aquifer system. Water samples were collected at the study well, at two other nearby public-supply wells, and at monitoring wells installed in or near the simulated zone of contribution to the study well. Untreated water samples from the study well contained arsenic at concentrations exceeding the Maximum Contaminant Level (MCL) of 10 micrograms per liter (µg/L) established by the U.S. Environmental Protection Agency for drinking water. Volatile organic compounds (VOCs) and nitrate also were detected, although at concentrations at least an order of magnitude less than established drinking-water standards, where such standards exist. Overall, study findings point to four primary influences on the movement and (or) fate of contaminants and the vulnerability of the public-supply well in Albuquerque: (1) groundwater age (how long ago water entered, or recharged, the aquifer), (2) groundwater development (introduction of manmade recharge and discharge sources), (3) natural geochemical conditions of the aquifer, and (4) seasonal pumping stresses. Concentrations of the isotope carbon-14 indicate that groundwater from most sampled wells in the local study area is predominantly water that entered, or recharged, the aquifer more than 6,000 years ago. However, the additional presence of the age tracer tritium in several groundwater samples at concentrations above 0.3 tritium units indicates that young (post-1950) recharge is reaching the aquifer across broad areas beneath Albuquerque. This young recharge is mixing with the thousands-of-years-old water, is migrating to depths as great as 245 feet below the water table, and is traveling to some (but not all) of the public-supply wells sampled. Most groundwater samples containing a fraction of young water also contain manmade VOCs, including chloroform (a byproduct of drinking-water chlorination), which indicates that the source of young recharge is, at least in part, infiltration of chlorinated municipal-supply water from leaking waterlines and sewerlines or from turf watering. Other likely manmade, urban recharge sources are seepage from constructed ponds and unlined portions of a stormwater diversion channel. A regional-scale computer-model simulation of groundwater flow and transport to the public-supply well shows that manmade sources of recharge and discharge that were added after about 1930 have greatly altered directions of groundwater flow near Albuquerque and have caused water levels to decline by as much as 120 feet. Local-scale simulations show that seasonal changes in the pumping schedule of the study well affect the age and quality of water produced by the well. Increased pumping during the summer causes significant volumes of water to flow downward from the shallow to the intermediate zones of the aquifer, causing a higher fraction of young water to be produced by the well in the summer than in the winter months and a corresponding increase in VOC detections in the summer relative to the winter. During the winter when the study-well pump is idle for several hours each day, old, high-arsenic water from the deep zone of the aquifer travels up the wellbore and exits into the intermediate zone of the aquifer. When the pump is activated in the winter (for a relatively short time each day), some of the leaked, high-arsenic water is recaptured by the well. This results in a higher arsenic concentration (commonly more than 12 µg/L) in water produced in the winter than in the summer, and a smaller fraction of young water being produced by the well in the winter than in the summer (6 percent in the winter, compared to 11 percent in the summer). Knowledge of the vertical flow direction (both natural and pumping-enhanced) in the vicinity of a long-screened well, coupled with understanding of variations in contaminant concentrations with depth in the aquifer, can help water managers predict the positive or negative effect that wellbore flow will have on water quality and can lead to development of strategies to mitigate contamination (such as changes in pumping schedules or development of devices to inhibit wellbore flow when the pump is off).

New Mexico↗
USGS2011

Vegetation communities at Big Muddy National Fish and Wildlife Refuge, Missouri

New and existing data were used to describe and map vegetation communities at Big Muddy National Fish and Wildlife Refuge. Existing data had been gathered during the growing seasons of 2002, 2003, and 2004. New data were collected in 2007 to describe previously unsampled communities and communities within which insufficient data had been collected. Plot data and field observations were used to describe 17 natural and semi-natural communities at the Association level of the National Vegetation Classification System (NVCS). Four ruderal communities not included in the NVCS are also described. Data were used to inform delineation of communities using aerial photos from 2000, 2002, 2003, 2005, 2006, and 2007. During this process, eleven additional land cover classes including cultural features, managed vegetation communities, and water features were identified. These features were mapped, some were described, but no vegetation data were collected. In 2009, nearly all community polygons were field visited and classified to the Association level. When necessary, polygon boundaries were adjusted based on field observations. The final map includes 482 polygons of 27 land cover classes encompassing 3,174 hectares on 5 units of the refuge. Data and information will inform the development of the refuge Comprehensive Conservation Plan.

Missouri↗
USGS2013

Nearshore thermal gradients of the Colorado River near the Little Colorado River confluence, Grand Canyon National Park, Arizona, 2010

Construction and operation of Glen Canyon Dam has dramatically impacted the flow of the Colorado River through Glen, Marble, and Grand Canyons. Extremes in both streamflow and water temperature have been suppressed by controlled releases from the dam. Trapping of sediment in Lake Powell, the reservoir formed by Glen Canyon Dam, has also dramatically reduced the supply of suspended sediment entering the system. These changes have altered the riverine ecosystem and the habitat of native species, including fish such as the endangered humpback chub ( Gila cypha ). Most native fish are adapted to seasonally warm water, and the continuous relatively cold water released by the dam is one of the factors that is believed to limit humpback chub growth and survival. While average mainstem temperatures in the Colorado River are well documented, there is limited understanding of temperatures in the nearshore environments that fish typically occupy. Four nearshore geomorphic unit types were studied between the confluence of the Colorado and Little Colorado Rivers and Lava Canyon in the summer and fall of 2010, for study periods of 10 to 27 days. Five to seven sites were studied during each interval. Persistent thermal gradients greater than the 0.2 °C accuracy of the instruments were not observed in any of the sampled shoreline environments. Temperature gradients between the shoreline and mainstem on the order of 4 °C, believed to be important to the habitat-seeking behavior of native or nonnative fishes, were not detected.

Arizona;Nevada;Utah↗
USGS2015

Fire patterns in the range of the greater sage-grouse, 1984-2013 - Implications for conservation and management

Fire ranks among the top three threats to the greater sage-grouse ( Centrocercus urophasianus ) throughout its range, and among the top two threats in the western part of its range. The national research strategy for this species and the recent U.S. Department of the Interior Secretarial Order 3336 call for science-based threats assessment of fire to inform conservation planning and fire management efforts. The cornerstone of such assessments is a clear understanding of where fires are occurring and what aspects of fire regimes may be shifting outside of their historical range of variation. This report fulfills this need by describing patterns of fire area, fire size, fire rotation, and fire season length and timing from 1984 to 2013 across the range of the greater sage-grouse. This information need is further addressed by evaluating the ecological and management implications of these fire patterns. Analyses are stratified by major vegetation types and the seven greater sage-grouse management zones, delineated regionally as four western and three eastern management zones. Soil temperature and moisture indicators of resilience to fire and resistance to cheatgrass invasion, and the potential for establishment of a grass/fire cycle, are used as unifying concepts in developing fire threat assessments for each analysis strata. The results indicate that fire threats are higher in the four western than in the three eastern management zones. Among the four western management zones, the Snake River Plain and the Columbia Basin ranked somewhat higher than the Southern Great Basin and Northern Great Basin in terms of fire effects on sage-grouse habitat. These results support the previous high ranking of fire as a threat to the greater sage-grouse in the western region. In contrast, considering the low rankings for fire threats in the eastern region, it may be useful to reconsider the relative importance of wildfire as a threat to greater sage-grouse in those three management zones.

California, Colorado, Idaho, Montana, Nevada, Oreg↗