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At least 793 records · Page 44Linked to original sources
USGS2012

Predicted eelgrass response to sea level rise and its availability to foraging Black Brant in Pacific coast estuaries

Managers need to predict how animals will respond to habitat redistributions caused by climate change. Our objective was to model the effects of sea level rise on total eelgrass ( Zostera marina ) habitat area and on the amount of that area that is accessible to Brant geese ( Branta bernicla ), specialist grazers of eelgrass. Digital elevation models were developed for seven estuaries from Alaska, Washington, California (USA), and Mexico. Scenarios of future total eelgrass area were derived from combinations of estuarine specific sediment and tectonic rates (i.e., bottom change rate) with three rates of eustatic sea level rise (ESLR). Percentages of total eelgrass areas that were accessible to foraging Brant were determined for December when the birds overwinter at more southerly sites and in April as they move north to sites where they build body stores on their way to nesting areas in Alaska. The modeling showed that accessible eelgrass area could be lower than total area due to how daytime low-tide height, eelgrass shoot length, and the upper elevation of eelgrass determined Brant-reaching depth. Projections of future eelgrass area indicated that present-day ESLR (2.8 mm/yr) and bottom change rates should sustain the current pattern of estuarine use by Brant except in Morro Bay, where use should decrease because eelgrass is being ejected from this estuary by a positive bottom change rate. Higher ESLR rates (6.3 and 12.7 mm/yr) should result in less Brant use of estuaries at the northern and southern ends of the flyway, particularly during the winter, but more use of mid-latitude estuaries. The capacity of mid-latitude estuaries to function as Brant feeding refugia, or for these estuaries and Izembek Lagoon to provide drift rather than attached leaves, is eventually limited by the decrease in total eelgrass area, which is a result of a light extinction affect on the eelgrass, or the habitat being pushed out of the estuary by positive tectonic rates. Management responses are limited to the increase or decrease of sediment supply and the relocation of levees to allow for upslope migration of eelgrass habitat.

Alaska;California;Washington↗
USGS2012

Neighborhood and habitat effects on vital rates: expansion of the Barred Owl in the Oregon Coast Ranges

In this paper, we modify dynamic occupancy models developed for detection-nondetection data to allow for the dependence of local vital rates on neighborhood occupancy, where neighborhood is defined very flexibly. Such dependence of occupancy dynamics on the status of a relevant neighborhood is pervasive, yet frequently ignored. Our framework permits joint inference about the importance of neighborhood effects and habitat covariates in determining colonization and extinction rates. Our specific motivation is the recent expansion of the Barred Owl (Strix varia) in western Oregon, USA, over the period 1990-2010. Because the focal period was one of dramatic range expansion and local population increase, the use of models that incorporate regional occupancy (sources of colonists) as determinants of dynamic rate parameters is especially appropriate. We began our analysis of 21 years of Barred Owl presence/nondetection data in the Tyee Density Study Area (TDSA) by testing a suite of six models that varied only in the covariates included in the modeling of detection probability. We then tested whether models that used regional occupancy as a covariate for colonization and extinction outperformed models with constant or year-specific colonization or extinction rates. Finally we tested whether habitat covariates improved the AIC of our models, focusing on which habitat covariates performed best, and whether the signs of habitat effects are consistent with a priori hypotheses. We conclude that all covariates used to model detection probability lead to improved AIC, that regional occupancy influences colonization and extinction rates, and that habitat plays an important role in determining extinction and colonization rates. As occupancy increases from low levels toward equilibrium, colonization increases and extinction decreases, presumably because there are more and more dispersing juveniles. While both rates are affected, colonization increases more than extinction decreases. Colonization is higher and extinction is lower in survey polygons with more riparian forest. The effects of riparian forest on extinction rates are greater than on colonization rates. Model results have implications for management of the invading Barred Owl, both through habitat alteration and removal.

Oregon↗
USGS2004

Importance of storm events in controlling ecosystem structure and function in a Florida Gulf Coast estuary

From 8/95 to 2/01, we investigated the ecological effects of intra- and inter-annual variability in freshwater flow through Taylor Creek in southeastern Everglades National Park. Continuous monitoring and intensive sampling studies overlapped with an array of pulsed weather events that impacted physical, chemical, and biological attributes of this region. We quantified the effects of three events representing a range of characteristics (duration, amount of precipitation, storm intensity, wind direction) on the hydraulic connectivity, nutrient and sediment dynamics, and vegetation structure of the SE Everglades estuarine ecotone. These events included a strong winter storm in November 1996, Tropical Storm Harvey in September 1999, and Hurricane Irene in October 1999. Continuous hydrologic and daily water sample data were used to examine the effects of these events on the physical forcing and quality of water in Taylor Creek. A high resolution, flow-through sampling and mapping approach was used to characterize water quality in the adjacent bay. To understand the effects of these events on vegetation communities, we measured mangrove litter production and estimated seagrass cover in the bay at monthly intervals. We also quantified sediment deposition associated with Hurricane Irene's flood surge along the Buttonwood Ridge. These three events resulted in dramatic changes in surface water movement and chemistry in Taylor Creek and adjacent regions of Florida Bay as well as increased mangrove litterfall and flood surge scouring of seagrass beds. Up to 5 cm of bay-derived mud was deposited along the ridge adjacent to the creek in this single pulsed event. These short-term events can account for a substantial proportion of the annual flux of freshwater and materials between the mangrove zone and Florida Bay. Our findings shed light on the capacity of these storm events, especially when in succession, to have far reaching and long lasting effects on coastal ecosystems such as the estuarine ecotone of the SE Everglades.

Journal of Coastal Research↗
USGS2018

Coherence between coastal and river flooding along the California coast

Water levels around river mouths are intrinsically determined by sea level and river discharge. If storm-associated coastal water-level anomalies coincide with extreme river discharge, landscapes near river mouths will be flooded by the hydrodynamic interactions of these two water masses. Unfortunately, the temporal relationships between ocean and river water masses are not well understood. The coherence between extreme river discharge and coastal water levels at six California river mouths across different climatic and geographic regions was examined. Data from river gauges, wave buoys, and tide gauges from 2007 to 2014 were integrated to investigate the relationships between extreme river discharge and coastal water levels near the mouths of the Eel, Russian, San Lorenzo, Ventura, Arroyo Trabuco, and San Diego rivers. Results indicate that mean and extreme coastal water levels during extreme river discharge are significantly higher compared with background conditions. Elevated coastal water levels result from the combination of nontidal residuals (NTRs) and wave setups. Mean and extreme (>99th percentile of observations) NTRs are 3–20 cm and ∼30 cm higher during extreme river discharge conditions, respectively. Mean and extreme wave setups are up to 40 cm and ∼20–90 cm higher during extreme river discharge than typical conditions, respectively. These water-level anomalies were generally greatest for the northern rivers and least for the southern rivers. Time-series comparisons suggest that increases in NTRs are largely coherent with extreme river discharge, owing to the low atmospheric pressure systems associated with storms. The potential flooding risks of the concurrent timing of these water masses are tempered by the mixed, semidiurnal tides of the region that have amplitudes of 2–2.5 m. In summary, flooding hazard assessments for floodplains near California river mouths for current or future conditions with sea-level rise should include the temporal coherence of fluvial and oceanic water levels.

California↗
USGS2018

Identifying and eliminating sources of recreational water quality degradation along an urban coast

Restoration of highly degraded urban coastal waters often requires large-scale, complex projects, but in the interim, smaller-scale efforts can provide immediate improvements to water quality conditions for visitor use. We examined short-term efforts to improve recreational water quality near the Grand Calumet River (GC) in the Laurentian Great Lakes. Identified as an Area of Concern (AOC) by the International Joint Commission, the GC has experienced years of industrial and municipal waste discharges, and as a result, coastal beaches have some of the highest rates of beach closings (>70%) in the United States. Project objectives were to identify sources of microbial contamination and to evaluate a short-term management solution to decrease beach closings: during 2015 (partial) and 2016 (season-long), canines were used to deter gull presence. Water samples were analyzed for Escherichia coli in 2015 and 2016, and fecal sources were evaluated using microbial source tracking markers (2015): human ( Bacteroides HF183, Methanobrevibacter nifH ), gull (Gull2), and dog (DogBact). Hydrometeorological conditions were simultaneously measured. Results indicated that human, gull, and canine fecal sources were present, with gulls being the dominant source. Escherichia coli densities were highly correlated with number of gulls present, Gull2 marker, and turbidity. Gull deterrence decreased E. coli and Gull2 marker detection during 2015, but numbers rebounded after program completion. The full-season program in 2016 resulted in lower E. coli densities and fewer beach closings. Large-scale restoration efforts are underway at this location, but short-term, small-scale projects can be useful for reducing beach closings and restoring ecosystem services.

Indiana↗
USGS1983

Organochlorine residues in Atlantic coast black-crowned night-heron eggs, 1979

Eggs of Black-crowned Night-Herons (Nycticorax nycticorax) were collected in 1979 from two colonies in North Carolina, two colonies in Rhode Island, and one colony in Massachusetts. Mean concentrations of DDE and PCBs were higher in the New England samples than in those from North Carolina, Mean concentrations of organochlorine contaminants in addled eggs collccted at two New England colonies were not significantly different from those in randomly selected eggs. In comparison with the results of a similar study conducted in 1973 at two of the New England colonies, concentrations of DDE in night-heron eggs were lower in 1979, DDD was less frequently detected, DDT and dieldrin were less frequently detected in eggs from one of the two colonies, and eggshell thickness was greater in 1979 for one of the colonies. PCB concentrations in eggs from one colony were lower in 1979 than 1973.

Colonial Waterbirds↗
USGS1983

Organochlorine residues in common tern eggs from nine Atlantic coast colonies, 1980

In 1980, 178 Common Tern (Sterna hirundo) eggs were collected in nine colonies from Rhode Island to North Carolina and were analyzed for organochlorines. DDE and PCBs were detected in most of the eggs. Mean concentrations of DDE and PCBs differed among colonies and seemed related to local contamination. Concentrations of DDE and PCBs in Common Tern eggs were well below those reported to have adverse effects in this species. In one colony, eggs of known laying sequence were collected. First, second, and third eggs in the clutch did not differ significantly from one another in shell weight, shell thickness, and concentration of DDE or PCBs.

Colonial Waterbirds↗
USGS1985

Habitat comparisons and productivity in nesting common terns on the mid-Atlantic coast

Nesting Common Terns (Sterna hirundo) were studied at a number of barrier beaches and small islands of tidal salt marsh in New Jersey and the Eastern Shore of Maryland-Virginina from 1980 through 1982. Data were collected on clutch sizes, nest spacing, and nesting success. The principal null hypothesis tested was that no difference in reproductive success exists between beach and marsh habitats. Nests were monitored from egg-laying in mid-May until mid-July when young fledged. Clutch sizes varied among colonies and across years but no systematic effect of year, habitat, or colony size on mean clutch size per colony was detected. Analyses of nest productivity (estimated using both the Mayfield method and using a colony average) failed to reveal significant effects of habitat or colony size but showed a stronger year effect. Storm tide flooding and egg chick disappearance (presumably predation by Herring Gulls Larus argentatus and Laughing Gulls L. atricilla nesting nearby) accounted for most nest failures. Losses due to both these mortality factors were unpredictable from year to year. Nest spacing in salt marsh colonies was much closer than it was on barrier beaches. In mixed-species colonies with Black Skimmers (Rynchops niger), distances between tern and skimmer nests were also much smaller in marsh colonies than they were on beaches. The limited amount of wrack (windrows of dead, matted vegetation) preferred by marsh-nesting terns probably explains these spacing differences. Several lines of evidence suggest that terns prefer beaches to marshes for nesting, however, the uncertainty of predation and flooding may often obscure any intrinsic differences in habitat quality. Long-term field studies are essential for testing hypotheses related to differential fitness of individuals among habitats.

Colonial Waterbirds↗
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↗
USGS1995

Upper Eocene impactites of the U.S. East Coast; depositional origins, biostratigraphic framework, and correlation

Similar successions of planktonic foraminifera, calcareous nannofossils, and bolboformids document coeval deposition of the Exmore impact breccia (Virginia Coastal Plain) and an impact ejecta layer at DSDP Site 612 (New Jersey Continental Slope). Both impactites accumulated in the late Eocene during the early part of biochrons P15 (planktonic foraminifera) and NP 19-20 (calcareous nannofossils), approximately 35.5-35.2 Ma. The impactite at Site 612 is part of an allochthonous debriite, 22.8 cm thick, displaced from the Toms Canyon impact crater, 40 km north-northwest of Site 612. The Exmore breccia, possibly 2000 m thick, is composed of debris displaced from the Chesapeake Bay impact crater, located in southeastern Virginia, 330 km southwest of Site 612.

U.S. East Coast↗
USGS1977

Mid-Atlantic coast osprey population: Present numbers, productivity, pollutant contamination, and status

An estimated 233 + 16 (95% C.I.) pairs of ospreys ( Pandion haliaetus ) nested in coastal New Jersey, Delaware, Maryland, and Virginia in 1975. The present populations were considerably smaller than those reported for selected locations at the turn of the century in these four states. The New Jersey population has continued to decline during the last 25 years, although it showed some signs of improved production in 1974-75. The insecticide DDT was used intensively in New Jersey for mosquito control from about 1946 until 1966; its use in the other states was much less intensive, and of shorter duration. In a segment of the pelaware population of ospreys, production was normal and numbers increased slightly in 1970-75. Fragmentary information from Maryland suggests that the number of pairs nesting on duck blinds was about the same in 1958 and 1975. The population in coastal Virginia north of Cape Henry increased from 1970 to 1975. DDE residues in osprey eggs were highest in the areas showing the greatest population declines and the lowest production rates.

Journal of Wildlife Management↗
USGS1989

Winter survival of female American black ducks on the Atlantic coast

We used radio telemetry to monitor the winter survival and cause-specific mortality of 227 female American black ducks ( Anas rubripes ) captured in New Jersey and Virginia, 1983-85. Mean survival rate for 19 December-15 February was 0.65. Survival from hunting and nonhunting risk was 0.84 and 0.78, respectively. Causes of nonhunting mortality included predation and emaciation (winter stress). After-hatch-year (AHY) ducks had a higher probability of survival than hatch-year (HY) ducks (0.73 vs. 0.60); most of this difference was related to survival from nonhunting risk. After-hatch-year ducks with body masses > median had a higher survival probability (0.85) than AHY ducks with < median body masses (0.61) because of differential survival from hunting risk. Hatch-year ducks had lower body mass than AHY ducks, but among HY ducks body mass was not related to survival. There were no consistent patterns in survivorship in relation to mean daily temperature, although the timing of the onset of low temperatures and storms may have influenced movement patterns. Our estimated survival rates are consistent with estimates from other studies of seasonal and annual survival. It may be possible to manage habitats for population segments at high risk (HY and low body mass birds), and increase black duck survivorship.

New Jersey, Virginia↗