These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Coelomic implantation of satellite transmitters in the bar-tailed godwit (Limosa lapponica) and the bristle-thighed curlew (Numenius tahitiensis) using propofol, bupivacaine, and lidocaine  

USGS Publications Warehouse

Intravenous propofol was used as a general anesthetic with a 2?1 (mg?mg) adjunctive mixture of lidocaine and bupivacaine as local anesthetics infiltrated into the surgical sites for implantation of satellite transmitters into the right abdominal air sac of 39 female and 4 male bar-tailed godwits (Limosa lapponica baueri and Limosa lapponica menzbeiri) and 11 female and 12 male bristle-thighed curlews (Numenius tahitiensis). The birds were captured on nesting grounds in Alaska, USA, and on overwintering areas in New Zealand and Australia from 2005 through 2008. As it was developed, the mass of the transmitter used changed yearly from a low of 22.4 ± 0.2 g to a high of 27.1 ± 0.2 g and weighed 25.1 ± 0.2 g in the final year. The mean load ratios ranged from 5.2% to 7.7% for godwits and from 5.7% to 7.5% for curlews and exceeded 5% for all years, locations, and genders of both species. The maximum load ratio was 8.3% for a female bar-tailed godwit implanted in Australia in 2008. Three godwits and no curlews died during surgery. Most birds were hyperthermic upon induction but improved during surgery. Two godwits (one in New Zealand and one in Australia) could not stand upon release, likely due to capture myopathy. These birds failed to respond to treatment and were euthanized. The implanted transmitters were used to follow godwits through their southern and northern migrations, and curlews were followed on their southern migration.

Mulcahy, Daniel M.; Gartrell, Brett; Gill, Robert E.; Tibbitts, T. Lee; Ruthrauff, Daniel R.

2011-01-01

2

Phylogeography of the Black-tailed Godwit Limosa limosa : substructuring revealed by mtDNA control region sequences  

Microsoft Academic Search

Black-tailed (Limosa limosa) and Hudsonian Godwits (L. haemastica) are sometimes described as a superspecies. The Black-tailed Godwit is further split into three subspecies on the basis of\\u000a morphological differences (L. l. limosa, L. l. islandica and L. l. melanuroides). We studied variation in partial mtDNA control region sequences among Black-tailed and Hudsonian Godwits which showed 5%\\u000a divergence. Black-tailed and Hudsonian

Jacob Höglund; Tomas Johansson; Albert Beintema; Hans Schekkerman

2009-01-01

3

Helminths of Hudsonian godwits, Limosa haemastica, from Alaska and Manitoba.  

PubMed

In total, 21 Hudsonian godwits, Limosa haemastica (Charadriiformes: Scolopacidae), were examined for helminths, 10 from Bristol Bay, Alaska, and 11 from Churchill, Manitoba. Seventeen species of helminths (9 trematodes, 6 cestodes, 2 nematodes) were collected, but only 1 trematode species, Plagiorchis elegans, was found in common between the 2 sample sites. All 17 species are new records for this host and 2 cestodes, Capsulata edenensis and Malika limosa, are new records for North America. In general, both prevalence and intensities were low, and species richness ranged from 1 to 6 (mean = 2.4). Most of the differences in the helminth faunas between the 2 sites were attributed to difference in habitats, freshwater in Manitoba versus saltwater in Alaska. PMID:17626373

Kinsella, John M; Didyk, Andy S; Canaris, Albert G

2007-06-01

4

Patterns in Nuclear and Mitochondrial DNA Reveal Historical and Recent Isolation in the Black-Tailed Godwit (Limosa limosa)  

PubMed Central

On the basis of morphological differences, three subspecies of Black-tailed Godwit (Limosa limosa) have been recognized (L. l. limosa, L. l. islandica and L. l. melanuroides). In previous studies mitochondrial DNA (mtDNA) sequence data showed minimal genetic divergence between the three subspecies and an absence of sub-structuring within L. l. limosa. Here, population genetic structure and phylogeographic patterns have been analyzed using COI, HVR1 and HVR2 mtDNA sequence data as well as 12 microsatellite loci (nuDNA). The nuDNA data suggest genetic differentiation between L. l. limosa from Sweden and The Netherlands, between L. l. limosa and L. l. islandica, but not between L. l. limosa and L. l. melanuroides. However, the mtDNA data were not consistent with the nuDNA pattern. mtDNA did support a split between L. l. melanuroides and L. l. limosa/L. l. islandica and also demonstrated two L. l. limosa haplotype clusters that were not geographically isolated. This genetic structure can be explained by a scenario of isolation of L. l. melanuroides from L. l. limosa in Beringia during the Last Glacial Maximum. During the Pleistocene separation of L. l. islandica from L. l. limosa occurred, followed by colonization of Iceland by the L. l. islandica during the Holocene. Within L. l. limosa founder events, followed by population expansion, took place during the Holocene also. According to the patterns observed in both markers together and their geographic separation, we propose that the three traditional subspecies indeed represent three separate genetic units. PMID:24416186

Trimbos, Krijn B.; Doorenweerd, Camiel; Kraaijeveld, Ken; Musters, C. J. M.; Groen, Niko M.; de Knijff, Peter; Piersma, Theunis; de Snoo, Geert R.

2014-01-01

5

Repeatable timing of northward departure, arrival and breeding in Black-tailed Godwits Limosa l. limosa , but no domino effects  

Microsoft Academic Search

When early breeding is advantageous, migrants underway to the breeding areas may be time stressed. The timing of sequential\\u000a events such as migration and breeding is expected to be correlated because of a “domino effect”, and would be of particular\\u000a biological importance if timings are repeatable within individuals between years. We studied a colour-marked population of\\u000a Black-tailed Godwits Limosa l.

Pedro M. Lourenço; Rosemarie Kentie; Julia Schroeder; Niko M. Groen; Jos C. E. W. Hooijmeijer; Theunis Piersma

6

Effects of Management Practices on Grassland Birds: Marbled Godwit  

Microsoft Academic Search

Marbled Godwit (Limosa fedoa): Breeding range Suitable habitat Area requirements Brown-headed Cowbird brood parasitism Breeding-season phenology and site fidelity Species’ response to management Management Recommendations Habitat Characteristics

Jill A. Dechant; Marriah L. Sondreal; Douglas H. Johnson; Lawrence D. Igl; Christopher M. Goldade; Melvin P. Nenneman; Betty R. Euliss

2001-01-01

7

STATUS OF MARBLED GODWITS IN SOUTH DAKOTA: BASED ON A 2007 LITERATURE SYNTHESIS  

Microsoft Academic Search

The current status of the marbled godwit (Limosa fedoa) population in South Dakota is of primary concern to natural resource managers because the two main habitats this species needs, native rangelands and wetlands, are being converted to other land uses at a rapid rate. We synthesized over 250 references to generate a comprehensive review on the occurrence and ecology of

Dawn M. Gardner; Kent C. Jensen; Kenneth F. Higgins

2008-01-01

8

STATUS OF HUDSONIAN GODWITS ON THE YUKON-KUSKOKWIM DELTA, ALASKA  

Microsoft Academic Search

Over 100 observations of the Hudsonian Godwit (Limosa haemastica) on the Yukon-Kuskokwim Delta in western Alaska since 1983 show that the species is a fairly common migrant, uncommon summer visitant, and rare, perhaps locally uncommon, breeder there. Spring arrival and fall departure dates are among the earliest and latest, respectively, in Alaska. Observations of breeding behavior and\\/or recently fledged young

BRIAN J. McCAFFERY; CHRISTOPHER M. HARWOOD

9

Shorebird community variations indicative of a general perturbation in the Mont-Saint-Michel bay (France)  

Microsoft Academic Search

The Mont-Saint-Michel bay located on the East Atlantic Flyway is the first site in France for wintering shorebirds, with, on average, 53000 individuals in January. Seven species represent 96% of that community: dunlin (Calidris alpina), knot (Calidris canutus), oystercatcher (Haematopus ostralegus), curlew (Numenius arquata), grey plover (Pluvialis squatarola), bar-tailed godwit (Limosa lapponica) and black-tailed godwit (Limosa limosa). The international bird

Marie-Christine Eybert; Thomas Geslin; Sophie Questiau; Eric Feunteun

2003-01-01

10

Insight on trace element detoxification in the Black-tailed Godwit (Limosa limosa) through genetic, enzymatic and metallothionein analyses  

E-print Network

, superoxide dismutase, glutathione peroxidase), and metallothionein (MT) levels. The results showed that Cr mechanisms such as metallothioneins. Keywords: metals; mercury; cadmium; bioaccumulation; biomarker

Boyer, Edmond

11

A comparison between high water and low water counts of shorebirds on the Wash, east England  

Microsoft Academic Search

Comparisons are made between counts of shorebirds at high water roosts and low water feeding grounds on the Wash, east England. During autumn and winter 1985–87, Shelduck, Tadorna tadorna, Oystercatcher, Haematopus ostralegus, Ringed Plover, Charadrius hiaticula, Grey Plover, Pluvialis squatarola, Knot, Calidris canutus, Dunlin, Calidris alpina, Bar-tailed Godwit, Limosa lapponica, Curlew, Numenius arquata Redshank, Tringa totanus and Turnstone, Arenaria interpres

M. G. Yates; J. D. Goss-Custard

1991-01-01

12

Variation in the innate and acquired arms of the immune system among five shorebird species  

Microsoft Academic Search

To contribute to an understanding of the evolutionary processes that shape variation in immune responses, we compared several components of the innate and acquired arms of the immune system in five related, but ecologically diverse, migratory shorebirds (ruff Philomachus pugnax L., ruddy turnstone Arenaria interpres L., bar-tailed godwit Limosa lapponica L., sanderling Calidris alba Pallas and red knot C. canutus

Luisa Mendes; Theunis Piersma; Dennis Hasselquist; Kevin D. Matson; Robert E. Ricklefs

2006-01-01

13

PCB burden and pattern in eggs of the curlew (numenius arquata) and the black-tailed godwit (limosa limosa) from Northwest Germany  

SciTech Connect

In recent decades the number of breedingpairs of the curlew has decreased in Westfalen (North-West Germany) as well as in the whole Federal Republic of Germany caused by permanent change or destruction of the environment. The hatching success decreased because of breeding in subideal habitats like fields resulting in starvation and reduced mobility to escape predators. In the District of Steinfurt (Westfalen, Germany), members of the {open_quotes}Workinggroup Wetmeadows{close_quotes} recognized decreasing hatching success of individually marked birds during several years. The burden of PCBs or other chlorinated compounds was hypothesized as a possible cause of this decrease. 18 refs., 4 figs.

Denker, E.; Buethe, A. [Chemisches Institut, Hannover (Germany)

1995-12-01

14

Shorebird community variations indicative of a general perturbation in the Mont-Saint-Michel bay (France).  

PubMed

The Mont-Saint-Michel bay located on the East Atlantic Flyway is the first site in France for wintering shorebirds, with, on average, 53,000 individuals in January. Seven species represent 96% of that community: dunlin (Calidris alpina), knot (Calidris canutus), oystercatcher (Haematopus ostralegus), curlew (Numenius arquata), grey plover (Pluvialis squatarola), bar-tailed godwit (Limosa lapponica) and black-tailed godwit (Limosa limosa). The international bird census organised by Wetlands International in mid-January gave us the opportunity to study, for a 23 years period, population variations in the bay. Despite a quite good carrying capacity, we showed that the decreasing proportion of 4 species in the bay relative to the other French populations may indicate a general perturbation of the bay. We discuss the different hypotheses to explain that observation. PMID:14558463

Eybert, Marie-Christine; Geslin, Thomas; Questiau, Sophie; Feunteun, Eric

2003-08-01

15

Metabolic profile of long-distance migratory flight and stopover in a shorebird  

PubMed Central

Migrating birds often complete long non-stop flights during which body energy stores exclusively support energetic demands. The metabolic correlates of such long-distance travel in free-living migrants are as yet poorly studied. Bar-tailed godwits, Limosa lapponica taymyrensis, undertake a 4500 km flight to their single spring stopover site and thus provide an excellent model in which to determine the energy fuels associated with endurance travel. To this end, we evaluated plasma concentrations of six key metabolites in arriving godwits caught immediately upon landing near their stopover site. Initial metabolite levels were compared with levels after 5 h of inactive rest to determine how flight per se affects energy metabolism. Birds refuelling on the stopover site were also examined. Arriving godwits displayed elevated plasma free fatty acids, glycerol and butyrate, confirming the importance of lipid fuel in the support of extended migratory activity. Furthermore, elevated plasma triglycerides in these birds suggest that fatty acid provisioning is facilitated through hepatic synthesis and release of neutral lipids, as previously hypothesized for small migrants with high mass-specific metabolic rates. Finally, elevations in plasma uric acid suggest that protein breakdown contributes to the support of long-distance movement, to possibly maintain citric acid cycle intermediates, gluconeogenesis and/or water balance. PMID:15705555

Landys, M?ta M.; Piersma, Theunis; Guglielmo, Christopher G.; Jukema, Joop; Ramenofsky, Marilyn; Wingfield, John C.

2005-01-01

16

Tennessee Valley Shorebird Assessment Project SHOREBIRD CONSERVATION AND MONITORING  

E-print Network

IN 1 YEAR BAR-TAILED GODWIT 6,000 MILES NON-STOP Tennessee Valley Shorebird Assessment Project NICHE Assessment Project Overview Construction of TVA dams over the past 60+ years has created extensive inland

Gray, Matthew

17

Absolute Consistency: Individual versus Population Variation in Annual-Cycle Schedules of a Long-Distance Migrant Bird  

PubMed Central

Flexibility in scheduling varies throughout an organism’s annual cycle, reflecting relative temporal constraints and fitness consequences among life-history stages. Time-selection can act at different scales, either by limiting the range of alternative strategies in the population, or by increasing the precision of individual performance. We tracked individual bar-tailed godwits Limosa lapponica baueri for two full years (including direct observation during non-breeding seasons in New Zealand and geolocator tracking of round-trip migrations to Alaska) to present a full annual-cycle view of molt, breeding, and migration schedules. At both population and individual scales, temporal variation was greater in post-breeding than pre-breeding stages, and greater in molts than in movements, but schedules did not tighten across successive stages of migration toward the breeding grounds. In general, individual godwits were quite consistent in timing of events throughout the year, and repeatability of pre-breeding movements was particularly high (r?=?0.82–0.92). However, we demonstrate that r values misrepresent absolute consistency by confounding inter- and intra-individual variation; the biological significance of r values can only be understood when these are considered separately. By doing so, we show that some stages have considerable tolerance for alternative strategies within the population, whereas scheduling of northbound migratory movements was similar for all individuals. How time-selection simultaneously shapes both individual and population variation is central to understanding and predicting adaptive phenological responses to environmental change. PMID:23342168

Conklin, Jesse R.; Battley, Phil F.; Potter, Murray A.

2013-01-01

18

Consistent annual schedules in a migratory shorebird  

PubMed Central

Many migratory birds start prebreeding moult and premigratory fuelling some months before the breeding season and face severe time constraints, while travelling up to 15?000?km between non-breeding and breeding grounds. Shorebirds typically leave Southern Hemisphere non-breeding areas over a 3–4 week period, but whether they benefit from interannually consistent timing of departure is unknown. Here, I show that individual bar-tailed godwits (Limosa limosa baueri) from New Zealand are highly consistent in their migratory scheduling. Most birds left within the same week each year (between-year repeatability, r, of 0.83) and adult males, which moult into a bright breeding plumage, were also highly repeatable in the extent of their prebreeding moult (r=0.86). This is consistent with the hypothesis that birds have individually optimized migration schedules. Within adult males, but not females, smaller birds tended to migrate earlier than large birds. Whether this reflects differences in size-related migration speed, optimal breeding time at different sites or size-related natural or sexual selection pressures, remains unknown. PMID:17148277

Battley, Phil F

2006-01-01

19

A possible case of contemporary selection leading to a decrease in sexual plumage dimorphism in a grassland-breeding shorebird  

Microsoft Academic Search

In sexually dimorphic species, males with more exaggerated plumage ornamentation generally have higher body condition, are preferred by females, and have higher reproductive output. In contrast to the majority of studies, we describe that less ornamented males of the monogamous and sexually dimorphic black-tailed godwit Limosa limosa were larger and heavier during late incubation than more ornamented males and were

Julia Schroeder; Pedro M. Lourenço; Jos C. E. W. Hooijmeijer; Theunis Piersma

2009-01-01

20

Variation in the innate and acquired arms of the immune system among five shorebird species.  

PubMed

To contribute to an understanding of the evolutionary processes that shape variation in immune responses, we compared several components of the innate and acquired arms of the immune system in five related, but ecologically diverse, migratory shorebirds (ruff Philomachus pugnax L., ruddy turnstone Arenaria interpres L., bar-tailed godwit Limosa lapponica L., sanderling Calidris alba Pallas and red knot C. canutus L.). We used a hemolysis-hemagglutination assay in free-living shorebirds to assess two of the innate components (natural antibodies and complement-mediated lysis), and a modified quantitative enzyme-linked immunosorbent assay in birds held in captivity to assess the acquired component (humoral antibodies against tetanus and diphtheria toxoid) of immunity. Ruddy turnstones showed the highest levels of both innate and acquired immune responses. We suggest that turnstones could have evolved strong immune responses because they scavenge among rotting organic material on the seashore, where they might be exposed to a particularly broad range of pathogens. Although ruffs stand out among shorebirds in having a high prevalence of avian malaria, they do not exhibit higher immune response levels. Our results indicate that relationships between immune response and infection are not likely to follow a broad general pattern, but instead depend on type of parasite exposure, among other factors. PMID:16391350

Mendes, Luisa; Piersma, Theunis; Hasselquist, Dennis; Matson, Kevin D; Ricklefs, Robert E

2006-01-01

21

1Unsolved Mystery Extreme Endurance Migration: What Is the Limit to Non- Stop Flight?  

E-print Network

Migratory birds have a history of challenging conventional wisdom about the limits of their endurance. More than half a century ago, many ornithologists doubted that a non-stop flight of 860 km across the Gulf of Mexico was possible for migratory (humming) birds [1]. But circumstantial and more direct evidence gathered in the following decade revealed that the Gulf of Mexico is a mere ditch to migratory birds [2,3], and that some are capable of non-stop flights of up to 5,000 km [4,5]. And now migratory birds have given their observers reason to pause yet again. In the past year, Gill et al. [6] have provided direct evidence that a shorebird, the Alaskan bar-tailed godwit (Limosa lapponica baueri) (Figure 1), makes its eight-day, 11,000-km autumn migration from Alaska to New Zealand in one step, with no stopovers to rest or refuel. This roughly doubles the previous maximum direct flight distance in birds, challenging experts to square this remarkable

Anders Hedenström

22

Upland Nesting Prairie Shorebirds: Use of Managed Wetland Basins and Accuracy of Breeding Surveys Utilisation de terres humides aménagées par les oiseaux de rivage des prairies nichant dans les hautes terres et précision des dénombrements d'individus nicheurs  

Microsoft Academic Search

Wetlands in southern Alberta are often managed to benefit waterfowl and cattle production. Effects on other species usually are not examined. I determined the effect of managed wetlands on upland- nesting shorebirds in southern Alberta by comparing numbers of breeding willets ( Catoptrophorus semipalmatus), marbled godwits (Limosa fedoa), and long-billed curlews ( Numenius americanus) among areas of managed wetlands, natural

Cheri L. Gratto-Trevor

23

Does Growth Rate Determine the Rate of Metabolism in Shorebird Chicks Living in the Arctic?  

Microsoft Academic Search

We measured resting and peak metabolic rates (RMR and PMR, respectively) during development of chicks of seven species of shorebirds: least sandpiper (Calidris minutilla; adult mass 20- 22 g), dunlin (Calidris alpina; 56-62 g), lesser yellowlegs (Tringa flavipes; 88-92 g), short-billed dowitcher (Limnodromus griseus; 85-112 g), lesser golden plover (Pluvialis dominicana; 150-156 g), Hudsonian godwit (Limosa haemastica; 205-274 g), and

Joseph B. Williams; B. Irene Tieleman; G. Henk Visser; Robert E. Ricklefs

2007-01-01

24

Spring-harvested game birds in the Western James Bay region of Northern Ontario, Canada: the amount of organochlorines in matched samples of breast muscle, skin, and abdominal fat  

Microsoft Academic Search

We examined matched-tissue samples (the right pectoral muscle plus the associated skin and fat was considered a breast portion)\\u000a of 81 spring-harvested waterfowl and 19 summer-harvested godwits (Limosa spp.) to assess the potential of these water birds contributing to the body burden of PCBs and DDT noted in First Nation\\u000a people of the western James Bay region, northern Ontario, Canada.

Leonard J. S. Tsuji; Ian D. Martin; Emily S. Martin; Alain LeBlanc; Pierre Dumas

2008-01-01

25

Effects of management practices on grassland birds: Marbled Godwit  

USGS Publications Warehouse

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which provides the fundamental components or keys to management for the species. A section on breeding range outlines the current breeding distribution of the species in North America, including areas that could not be mapped using BBS data. The suitable habitat section describes the breeding habitat and occasionally microhabitat characteristics of the species, especially those habitats that occur in the Great Plains. Details on habitat and microhabitat requirements often provide clues to how a species will respond to a particular management practice. A table near the end of the account complements the section on suitable habitat, and lists the specific habitat characteristics for the species by individual studies. A special section on prey habitat is included for those predatory species that have more specific prey requirements. The area requirements section provides details on territory and home range sizes, minimum area requirements, and the effects of patch size, edges, and other landscape and habitat features on abundance and productivity. It may be futile to manage a small block of suitable habitat for a species that has minimum area requirements that are larger than the area being managed. The Brown-headed Cowbird (Molothrus ater) is an obligate brood parasite of many grassland birds. The section on cowbird brood parasitism summarizes rates of cowbird parasitism, host responses to parasitism, and factors that influence parasitism, such as nest concealment and host density. The impact of management depends, in part, upon a species' nesting phenology and biology. The section on breeding-season phenology and site fidelity includes details on spring arrival and fall departure for migratory populations in the Great Plains, peak breeding periods, the tendency to renest after nest failure or success, and the propensity to return to a previous breeding site. The duration and timing of breeding varies among regions and years. Species' response to management summarizes the current knowledge and major findings in the literature on the effects of different management practices on the species. The section on management recommendations complements the previous section and summarizes specific recommendations for habitat management provided in the literature. If management recommendations differ in different portions of the species' breeding range, recommendations are given separately by region. The literature cited contains references to published and unpublished literature on the management effects and habitat requirements of the species. This section is not meant to be a complete bibliography; for a searchable, annotated bibliography of published and unpublished papers dealing with habitat needs of grassland birds and their responses to habitat management, use the Grassland and Wetland Birds Bibliography on the home page of this resource.

Dechant, Jill A.; Sondreal, Marriah L.; Johnson, Douglas H.; Igl, Lawrence D.; Goldade, Christopher M.; Nenneman, Melvin P.; Euliss, Betty R.

1998-01-01

26

Sex Promotes Spatial and Dietary Segregation in a Migratory Shorebird during the Non-Breeding Season  

PubMed Central

Several expressions of sexual segregation have been described in animals, especially in those exhibiting conspicuous dimorphism. Outside the breeding season, segregation has been mostly attributed to size or age-mediated dominance or to trophic niche divergence. Regardless of the recognized implications for population dynamics, the ecological causes and consequences of sexual segregation are still poorly understood. We investigate the foraging habits of a shorebird showing reversed sexual dimorphism, the black-tailed godwit Limosa limosa, during the winter season, and found extensive segregation between sexes in spatial distribution, microhabitat use and dietary composition. Males and females exhibited high site-fidelity but differed in their distributions at estuary-scale. Male godwits (shorter-billed) foraged more frequently in exposed mudflats than in patches with higher water levels, and consumed more bivalves and gastropods and fewer polychaetes than females. Females tended to be more frequently involved and to win more aggressive interactions than males. However, the number of aggressions recorded was low, suggesting that sexual dominance plays a lesser role in segregation, although its importance cannot be ruled out. Dimorphism in the feeding apparatus has been used to explain sex differences in foraging ecology and behaviour of many avian species, but few studies confirmed that morphologic characteristics drive individual differences within each sex. We found a relationship between resource use and bill size when pooling data from males and females. However, this relationship did not hold for either sex separately, suggesting that differences in foraging habits of godwits are primarily a function of sex, rather than bill size. Hence, the exact mechanisms through which this segregation operates are still unknown. The recorded differences in spatial distribution and resource use might expose male and female to distinct threats, thus affecting population dynamics through differential mortality. Therefore, population models and effective conservation strategies should increasingly take sex-specific requirements into consideration. PMID:22479448

Catry, Teresa; Alves, José A.; Gill, Jennifer A.; Gunnarsson, Tómas G.; Granadeiro, José P.

2012-01-01

27

Impacts of man-made landscape features on numbers of estuarine waterbirds at low tide.  

PubMed

The potential impact of human disturbance on wintering waterbirds using intertidal mudflats was considered by relating their numbers to the presence of nearby footpaths, roads, railroads, and towns. Data were obtained for six English estuaries from the Wetland Bird Survey Low Tide Count scheme. Counts were undertaken monthly from November to February, and data were available for an average of 2.8 years per estuary for the period 1992-1993 to 1999-2000. Count sections and the positions of man-made landscape features were mapped using a GIS. Generalized linear models tested whether bird numbers varied according to the estuary, month, area, whether or not the section bordered water, and the proportion of each section within a specified distance of each landscape feature. In addition, the proximity of sections to the nearest footpath access point was considered. Numbers of six of nine species, northern shelduck (Tadorna tadorna), red knot (Calidris canutus), dunlin (Calidris alpina), black-tailed godwit (Limosa limosa), Eurasian curlew (Numenius arquata) and common redshank (Tringa totanus), were significantly lower where a footpath was close to a count section, while those of brant (Branta bernicla) were greater. Northern shelduck, black-bellied plover (Pluvialis squatarola), dunlin, and black-tailed godwit numbers were reduced close to railroads and those of common ringed plover (Charadrius hiaticula), black-bellied plover, and Eurasian curlew close to roads. Common ringed plover numbers were greater close to towns. The relative distances to which species were affected by footpaths corresponded to published information concerning their flight distances in response to human disturbance. The study provided evidence that sustained disturbance associated with footpaths, roads, and railroads reduced local habitat quality for waterbirds and the carrying capacity of estuaries. PMID:12402099

Burton, Niall H K; Armitage, Michael J S; Musgrove, Andrew J; Rehfisch, Mark M

2002-12-01

28

[Temporal and spatial distribution of shorebirds (Charadriiformes) at San Ignacio Lagoon, Baja California Sur, Mexico].  

PubMed

Baja California Peninsula has several wetlands that represent important ecosystems for shorebirds. San Ignacio Lagoon is one of these sites, and supports 10% of the total abundance of shorebirds reported in this Peninsula. Since there is few information about this group in this area, we studied spatial and temporal changes in abundance and distribution of shorebirds in San Ignacio Lagoon. For this, we conducted twelve monthly censuses (October 2007-September 2008) on the entire internal perimeter of the lagoon, which we divided into four areas: two at the North and two at the South. We observed a seasonal pattern, with the lowest abundance in May (1 585 birds) and the highest in October (47 410). The most abundant species were Marbled Godwits (Limosa fedoa; 55% of the total records), Western Sandpipers (Calidris mauri; 23%), and Willet (Tringa semipalmata; 10%). All three species were more abundant in autumn; for both, the Marbled Godwit and Willet, we observed their highest numbers in winter and spring, while the Western Sandpiper showed noticeable oscillations, reaching a maximum in early winter (December). In summer, Marbled Godwit and Willet were the only birds present but in lower numbers. Here present the first records of the Pacific Red Knot (Calidris canutus roselaari) in the area. Bird abundance and species richness were influenced seasonally by migration and spatially by sites in the lagoon. The greatest shorebird abundance was in the South area of the lagoon, probably because of better accessibility to food. Our results allowed the inclusion of San Ignacio Lagoon in the Western Hemisphere Shorebirds Reserve Network (WHSRN) as a site of international importance. PMID:23894976

Mendoza, Luis Francisco; Carmona, Roberto

2013-03-01

29

An exception to the rule: carry-over effects do not accumulate in a long-distance migratory bird.  

PubMed

Recent years have seen a growing consensus that events during one part of an animal's annual cycle can detrimentally affect its future fitness. Notably, migratory species have been shown to commonly display such carry-over effects, facing severe time constraints and physiological stresses that can influence events across seasons. However, to date, no study has examined a full annual cycle to determine when these carry-over effects arise and how long they persist within and across years. Understanding when carry-over effects are created and how they persist is critical to identifying those periods and geographic locations that constrain the annual cycle of a population and determining how selection is acting upon individuals throughout the entire year. Using three consecutive years of migration tracks and four consecutive years of breeding success data, we tested whether carry-over effects in the form of timing deviations during one migratory segment of the annual cycle represent fitness costs that persist or accumulate across the annual cycle for a long-distance migratory bird, the Hudsonian godwit, Limosa haemastica. We found that individual godwits could migrate progressively later than population mean over the course of an entire migration period, especially southbound migration, but that these deviations did not accumulate across the entire year and were not consistently detected among individuals across years. Furthermore, neither the accumulation of lateness during previous portions of the annual cycle nor arrival date at the breeding grounds resulted in individuals suffering reductions in their breeding success or survival. Given their extreme life history, such a lack of carry-over effects suggests that strong selection exists on godwits at each stage of the annual cycle and that carry-over effects may not be able to persist in such a system, but also emphasizes that high-quality stopover and wintering sites are critical to the maintenance of long-distance migratory populations. PMID:24523862

Senner, Nathan R; Hochachka, Wesley M; Fox, James W; Afanasyev, Vsevolod

2014-01-01

30

An Exception to the Rule: Carry-Over Effects Do Not Accumulate in a Long-Distance Migratory Bird  

PubMed Central

Recent years have seen a growing consensus that events during one part of an animal's annual cycle can detrimentally affect its future fitness. Notably, migratory species have been shown to commonly display such carry-over effects, facing severe time constraints and physiological stresses that can influence events across seasons. However, to date, no study has examined a full annual cycle to determine when these carry-over effects arise and how long they persist within and across years. Understanding when carry-over effects are created and how they persist is critical to identifying those periods and geographic locations that constrain the annual cycle of a population and determining how selection is acting upon individuals throughout the entire year. Using three consecutive years of migration tracks and four consecutive years of breeding success data, we tested whether carry-over effects in the form of timing deviations during one migratory segment of the annual cycle represent fitness costs that persist or accumulate across the annual cycle for a long-distance migratory bird, the Hudsonian godwit, Limosa haemastica. We found that individual godwits could migrate progressively later than population mean over the course of an entire migration period, especially southbound migration, but that these deviations did not accumulate across the entire year and were not consistently detected among individuals across years. Furthermore, neither the accumulation of lateness during previous portions of the annual cycle nor arrival date at the breeding grounds resulted in individuals suffering reductions in their breeding success or survival. Given their extreme life history, such a lack of carry-over effects suggests that strong selection exists on godwits at each stage of the annual cycle and that carry-over effects may not be able to persist in such a system, but also emphasizes that high-quality stopover and wintering sites are critical to the maintenance of long-distance migratory populations. PMID:24523862

Senner, Nathan R.; Hochachka, Wesley M.; Fox, James W.; Afanasyev, Vsevolod

2014-01-01

31

Sex-biases in distribution and resource use at different spatial scales in a migratory shorebird  

PubMed Central

In migratory species, sexual size dimorphism can mean differing energetic requirements for males and females. Differences in the costs of migration and in the environmental conditions occurring throughout the range may therefore result in sex-biases in distribution and resource use at different spatial scales. In order to identify the scale at which sexual segregation operates, and thus the scale at which environmental changes may have sex-biased impacts, we use range-wide tracking of individually color-ringed Icelandic black-tailed godwits (Limosa limosa islandica) to quantify sexual segregation at scales ranging from the occupation of sites throughout the non-breeding range to within-site differences in distribution and resource use. Throughout the range of this migratory shorebird, there is no evidence of large-scale sex differences in distribution during the non-breeding season. However, the sexes differ in their selection of prey types and sizes, which results in small-scale sexual segregation within estuaries. The scale of sexual segregation therefore depends on the scale of variation in resource distribution, which, in this system, is primarily within estuaries. Sexual segregation in within-site distribution and resource use means that local-scale anthropogenic impacts on estuarine benthic prey communities may disproportionately affect the sexes in these migratory shorebirds. PMID:23610645

Alves, José A; Gunnarsson, Tómas G; Potts, Peter M; Sutherland, William J; Gill, Jennifer A

2013-01-01

32

Variation in numbers and behaviour of waders during the tidal cycle: implications for the use of estuarine sediment flats  

NASA Astrophysics Data System (ADS)

Estuarine sediment flats are essential feeding areas for waders, but their exploitation is constrained by the movements of tides. In this cyclic environment the exposure period of sediment flats decreases several fold from upper to lower flats, and the moving tidal waterline briefly creates particular conditions for waders and their prey. This study attempts to determine how the exposure period and the movement of the tide line influence the use of space and food resources by waders across the sediment flats. Wader counts and observations of feeding behaviour were carried out in all phases of the tidal cycle, in plots forming a transect from upper to lower flats, thus representing a gradient of exposure periods. Pecking, prey intake, and success rates varied little along the gradient. Some species actively followed the tide line while foraging, whereas others are evenly spread over the exposed flats. Black-tailed Godwit, Dunlin and Avocet were 'tide followers', whereas Grey Plover, Redshank and Bar-tailed Godwit were 'non-followers'. Densities of 'followers' near the tide line were up to five times higher than elsewhere. Species differed markedly in the way they used space on the flats, but in general the rate of biomass acquisition (in grams of ash-free dry weight per time exposed) was much higher in lower flats. However, this preference was insufficient to counter the much longer exposure of the upper flats, so the total amount of biomass consumed on the latter was greater. Therefore, it was in these upper flats that waders fulfilled most of their energetic needs. Consequently, upper flats are of particular importance for the conservation of wader assemblages, but because they are usually closer to shore they tend to suffer the highest pressure from disturbance and land reclamation.

Granadeiro, José P.; Dias, Maria P.; Martins, Ricardo C.; Palmeirim, Jorge M.

2006-05-01

33

Trophic resource partitioning within a shorebird community feeding on intertidal mudflat habitats  

NASA Astrophysics Data System (ADS)

In ecological systems, it is necessary to describe the trophic niches of species and their segregation or overlap to understand the distribution of species in the community. In oceanic systems, the community structure of top predators such as seabird communities has been well documented with many studies in several biogeographical areas. But for coastal habitats, very few investigations on the trophic structure have been carried out in avian communities. In this study, the trophic resource partitioning was investigated on eight of the most abundant species of a shorebird community on the central Atlantic coast of France. Our work comprised a comprehensive sample of birds with different ecomorphogical patterns and data on their main prey to encompass potential sources of overlap and segregation in this community. We examined the stable carbon (?13C) and nitrogen (?15N) isotopic composition of blood to investigate the trophic structure (1) on a temporal scale by comparing migration and wintering periods; (2) on a spatial scale through inter-site comparisons; and (3) on the community level within groups of phylogenetically related species. Diets appeared different in several cases between periods, between sites and between juveniles and adults for the same sites. A clear trophic partitioning was established with four functional groups of predators in winter inside the community. The Grey Plover, the Bar-tailed Godwit, the Curlew and a majority of the dunlins were worm-eaters mainly feeding on Nereis diversicolor or Nephtys hombergii. Two species were predominantly deposit-suspensivorous mollusc-eaters, including the Red Knot and the Black-tailed Godwit feeding mainly on Macoma balthica. The Oystercatcher fed mainly on suspensivorous molluscs like Cerastodrema edule and two species including the Redshank and some dunlins adopted opportunistic behaviours feeding on mudflat and/or in marshes.

Bocher, Pierrick; Robin, Frédéric; Kojadinovic, Jessica; Delaporte, Philippe; Rousseau, Pierre; Dupuy, Christine; Bustamante, Paco

2014-09-01

34

Proceedings of the South Dakota Academy of Science,Vol. 87 (2008) 85 STATUS OF MARBLED GODWITS IN SOUTH DAKOTA  

E-print Network

market and sport hunting during the late 1800s and early 1900s (Brown et al. 2001). The Migratory Bird Convention Act of 1916 reduced hunting pressure, but a large portion of breeding habitat had already been

35

Does growth rate determine the rate of metabolism in shorebird chicks living in the Arctic?  

PubMed

We measured resting and peak metabolic rates (RMR and PMR, respectively) during development of chicks of seven species of shorebirds: least sandpiper (Calidris minutilla; adult mass 20-22 g), dunlin (Calidris alpina; 56-62 g), lesser yellowlegs (Tringa flavipes; 88-92 g), short-billed dowitcher (Limnodromus griseus; 85-112 g), lesser golden plover (Pluvialis dominicana; 150-156 g), Hudsonian godwit (Limosa haemastica; 205-274 g), and whimbrel (Numenius phaeopus; 380 g). We tested two opposing hypotheses: the growth rate-maturity hypothesis, which posits that growth rate in chicks is inversely related to functional maturity of tissues, and the fast growth rate-high metabolism hypothesis, which suggests that rapid growth is possible only with a concomitant increase in either RMR or PMR. We have found no evidence that chicks of shorebirds with fast growth rates have lower RMRs or lower PMRs, as would be predicted by the growth rate-maturity hypothesis, but our data suggested that faster-growing chest muscles resulted in increased thermogenic capacity, consistent with the fast growth-high metabolism hypothesis. The development of homeothermy in smaller species is a consequence primarily of greater metabolic intensities of heat-generating tissues. The maximum temperature gradient between a chick's body and environment that can be maintained in the absence of a net radiative load increased rapidly with body mass during development and was highest in least sandpipers and lowest among godwits. Chicks of smaller species could maintain a greater temperature gradient at a particular body mass because of their higher mass-specific maximum metabolic rates. PMID:17717813

Williams, Joseph B; Tieleman, B Irene; Visser, G Henk; Ricklefs, Robert E

2007-01-01

36

Trace element accumulation in relation to trophic niches of shorebirds using intertidal mudflats  

NASA Astrophysics Data System (ADS)

This study investigated the link between trace element concentrations and respective diets of two shorebird species present in the Pertuis Charentais, Atlantic coast of France: the Dunlin (Calidris alpina) and Redshank (Tringa totanus). Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidney, muscle and feathers of 28 dunlins and 15 redshanks accidentally dead during catches by mist net. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers to determine whether differences in diet explained the variations in elemental levels. These results were compared to previous data obtained on two other shorebird species present on the same sites: the Black-tailed Godwit (Limosa limosa) and the Red Knot (Calidris canutus). This study demonstrated that shorebirds of the Pertuis Charentais were characterized by differential trace element bioaccumulation. Arsenic and Se concentrations in internal tissues were elevated in red knots and dunlins, whereas redshanks displayed higher Cd concentrations. These trace element bioaccumulation discrepancies could mainly come from divergences of trophic habits between shorebirds. Species with the highest trophic position displayed the highest Hg concentrations in the liver, muscle and feathers demonstrating therefore the biomagnification potential of this metal, as opposed to Cd and Pb. The same trend was observed in muscle and feathers for Se and only in feathers for As. These data highlighted the need to study several tissues to obtain a full comprehension of trace element exposure and pathways especially for long-distance migrating species using various habitats and sites.

Lucia, Magali; Bocher, Pierrick; Chambosse, Mélanie; Delaporte, Philippe; Bustamante, Paco

2014-09-01

37

Validation of the doubly labeled water method in growing precocial birds: the importance of assumptions concerning evaporative water loss.  

PubMed

The doubly labeled water (DLW) method was validated against respiration gas analysis in growing precocial chicks of the black-tailed godwit (Limosa limosa) and the northern lapwing (Vanellus vanellus). To calculate the rate of CO2 production from DLW measurements, Lifson and McClintock's equations (6) and (35) were employed, as well as Speakman's equation (7.17) (all single-pool models). The average errors obtained with the first two equations (+7.2% and -11.6%, respectively) differed significantly from zero but not the error obtained with Speakman's equation (average: -2.9%). The latter error could be reduced by taking a fractional evaporative water loss of 0.13, instead of the value of 0. 25 recommended by Speakman. Application of different two-pool models resulted in relative errors of the DLW method of -15.9% or more. After employing the single-pool model with a fractional evaporative water loss value of 0.13, it was found that there was no relationship between the relative growth rate of the chick and the relative error of the DLW method. Recalculation of previously published results on Arctic tern (Sterna paradisaea) chicks revealed that the fit of the validation experiment could be considerably improved by employing a single-pool model and assuming a fractional evaporative water loss of 0.20 instead of the value of 0.50 taken originally. After employing the value of 0.20, it was found that there was no relationship between the relative growth rate of the chick and the relative error of the DLW method. This suggests that isotope incorporation into new body substances does not cause a detectable error. Thus, the DLW method seems to be applicable in young birds growing as fast as 20% d-1, after making adjustments for the fractional evaporative water loss. We recommend Speakman's equation (7.17) for general use in growing birds when evaporation is unknown. PMID:10603338

Visser, G H; Schekkerman, H

1999-01-01

38

Spring-harvested game birds in the Western James Bay region of Northern Ontario, Canada: the amount of organochlorines in matched samples of breast muscle, skin, and abdominal fat.  

PubMed

We examined matched-tissue samples (the right pectoral muscle plus the associated skin and fat was considered a breast portion) of 81 spring-harvested waterfowl and 19 summer-harvested godwits (Limosa spp.) to assess the potential of these water birds contributing to the body burden of PCBs and DDT noted in First Nation people of the western James Bay region, northern Ontario, Canada. In general, the dabbling ducks (mallard duck, Anas platyrhynchos; and northern pintail, A. acuta) had significantly lower percent lipid (gravimetrically determined) values in skin tissue, fat tissue, and breast muscle compared to the goose species (Canada goose, Branta canadensis; lesser snow goose, Chen caerulescens); godwits had percent lipid values not significantly different than ducks and geese. Also, the percent lipid values in skin for all species of birds examined approached those found in fat tissue. Organochlorine data were expressed as the amount (microg) of each contaminant per breast portion to show contaminant consumption in terms of typical and easily recognizable dietary portions; direct comparisons were made to acceptable daily intake (ADI) or tolerable daily intake (TDI) values as recommended by Health Canada. Significant differences in the amount of organochlorines between bird species for skin, fat tissue, and breast muscle samples were found. In general, breast portions from snow geese contained the least amount of organochlorines, followed by godwits (except for mirex) and then Canada geese; the dabbling ducks had the greatest amount of organochlorines on a breast portion basis. However, on average, no 60 kg person would exceed the calculated organochlorine ADI/TDI values consuming one breast portion (i.e., breast + associated skin and fat), but the maximum value of SigmaPCBs for skin tissue alone in male mallards (47 microg) was more than twice the ADI/TDI (18 microg/day); while, that in fat tissue alone (17 microg) approached the ADI/TDI. Thus, the consumption of dabbling ducks by children is an issue that should be explored further, if tissue other than breast muscle is eaten. Lastly, the consumption of waterfowl was a source of PCBs for people of Fort Albany and Kashechewan, but not DDT, as this organochlorine was infrequently detected. PMID:18058032

Tsuji, Leonard J S; Martin, Ian D; Martin, Emily S; LeBlanc, Alain; Dumas, Pierre

2008-11-01

39

Abdominally implanted satellite transmitters affect reproduction and survival rather than migration of large shorebirds  

USGS Publications Warehouse

Satellite telemetry has become a common technique to investigate avian life-histories, but whether such tagging will affect fitness is a critical unknown. In this study, we evaluate multi-year effects of implanted transmitters on migratory timing and reproductive performance in shorebirds. Shorebirds increasingly are recognized as good models in ecology and evolution. That many of them are of conservation concern adds to the research responsibilities. In May 2009, we captured 56 female Black-tailed Godwits Limosa limosa limosa during late incubation in The Netherlands. Of these, 15 birds were equipped with 26-g satellite transmitters with a percutaneous antenna (7.8 % ± 0.2 SD of body mass), surgically implanted in the coelom. We compared immediate nest survival, timing of migration, subsequent nest site fidelity and reproductive behaviour including egg laying with those of the remaining birds, a comparison group of 41 females. We found no effects on immediate nest survival. Fledging success and subsequent southward and northward migration patterns of the implanted birds conformed to the expectations, and arrival time on the breeding grounds in 2010–2012 did not differ from the comparison group. Compared with the comparison group, in the year after implantation, implanted birds were equally faithful to the nest site and showed equal territorial behaviour, but a paucity of behaviours indicating nests or clutches. In the 3 years after implantation, the yearly apparent survival of implanted birds was 16 % points lower. Despite intense searching, we found only three eggs of two implanted birds; all were deformed. A similarly deformed egg was reported in a similarly implanted Whimbrel Numenius phaeopus returning to breed in central Alaska. The presence in the body cavity of an object slightly smaller than a normal egg may thus lead to egg malformation and, likely, reduced egg viability. That the use of implanted satellite transmitters in these large shorebirds reduced nesting propensity and might also lead to fertility losses argues against the use of implanted transmitters for studies on breeding biology, and for a careful evaluation of the methodology in studies of migration.

Hooijmeijer, Jos C.E.W.; Gill, Robert E.; Mulcahy, Daniel M.; Tibbitts, T. Lee; Kentie, Rosemarie; Gerritsen, Gerrit J.; Bruinzeel, Leo W.; Tijssen, David C.; Harwood, Christopher M.; Piersma, Theunis

2014-01-01

40

Population identification of western hemisphere shorebirds throughout the annual cycle  

USGS Publications Warehouse

Identification of relationships among geographically distinct populations of migratory species can provide an understanding of breeding and natal philopatry, migration pathways, and population mixing during winter. We used random amplified polymorphic DNA (RAPD) analyses to search for markers specific to difficult-to-differentiate shorebird species (e.g. long-billed dowitcher Limnodromus scolopaceus and short-billed dowitcher L. griseus) as well as geographically distinct breeding populations of Hudsonian godwits Limosa haemastica, red-necked phalaropes Phalaropus lobatus, semipalmated plovers Charadrius semipalmatus, dunlin Calidris alpina, pectoral sandpipers C. melanotos, semipalmated sandpipers C. pusilla and western sandpipers C. mauri. Markers clearly differentiated all shorebird species. Estimates of population differentiation varied greatly among species (FST= 0.095a??0.685) and correlated with interspecific variation in philopatry and geographical separation of breeding populations. We assigned individuals to putative breeding locales with greater certainty in well-differentiated species than in poorly differentiated species. Our findings indicate specific phylogeographical structure varies among species, which has strong implications for conservation of habitats within migratory corridors. We suggest that RAPDs are useful in identifying geographical populations of migratory species and that molecular markers should be considered for tracking migratory birds throughout the annual cycle.

Haig, Susan M.; Gratto-Trevor, C. L.; Mullins, Thomas D.; Colwell, M.A.

1997-01-01

41

Remote sensing aides studies of climate and wildlife in the Arctic-on land, at sea, and in the air (Invited)  

NASA Astrophysics Data System (ADS)

Every day a variety of remote sensing technologies collects large volumes of data that are supporting new analyses and new interpretations about how weather and climate influence the status and distribution of wildlife populations worldwide. Understanding how climate presently affects wildlife is crucial for projecting how climate change could affect wildlife in the future. This talk highlights climate-related wildlife studies by the US Geological Survey in the Arctic. The Arctic is experiencing some of the most pronounced climate changes on earth, raising concerns for species that have evolved seasonal migration strategies tuned to habitat availability and quality. On land, large herbivores such as caribou select concentrated calving areas with high abundance of rapidly growing vegetation and calf survival increases with earlier green-up and with the quantity of food available to cows at peak lactation. Geese time their migrations and reproductive efforts to coincide with optimal plant phenology and peak nutrient availability and departures from this synchrony can influence the survival of goslings. At sea, the habitats of polar bears and other sea-ice-dependent species have dramatically changed over just the past two decades. The ice pack is comprised of younger ice that melts much more extensively during summer-a trend projected to continue by all general circulation models under all but the most aggressive greenhouse gas mitigation scenarios. Studies show that by mid-century optimal polar bear habitats will be so reduced that the species may become extirpated from some regions of the Arctic. In the air, a variety of shorebird species make non-stop endurance flights between northern and southern hemispheres. The bar-tailed godwit undertakes a trans-Pacific flight between Alaska and Australasia that lasts more than seven days and spans more than 10,000 km. Studies show that godwits time their flights to coincide with favorable wind conditions, but stochastic weather events en route can impose energetic costs that affect reproduction and possibly survival. As more is learned about how climate and climate change affect species and ecosystems, better adaptive management decisions can be made. Remote sensing will continue to play an essential role.

Douglas, D. C.; Durner, G. M.; Gill, R. E.; Griffith, B.; Schmutz, J. A.

2013-12-01

42

Mercury concentrations in muscle, brain and bone of Western Alaskan waterfowl.  

PubMed

Total mercury (THg), which includes both inorganic (Hg(2+)) and methylmercury (MeHg) species, has been reported for seabirds in the North Pacific and Alaska. For the Yup'ik and Aleut people of Alaska, waterfowl are a small but important seasonal component of the diet, but many Alaskan species have not been studied extensively for the presence of mercury. Birds are good subjects for examination of mercury concentrations because they feed at different trophic levels, they can be long-lived, and many are both abundant and widely distributed. In this study, we present the levels of mercury in muscle, brain, and bone tissue of 140 birds taken by subsistence food users across Western Alaska. THg wet weight mean concentrations in the 18 species of waterfowl surveyed ranged from 0.8 to 268.6 ng/g in muscle, from 0.4 to 197.7 ng/g in brain and from 0.7 to 422.9 ng/g in bone. The null hypothesis that there are no interspecific differences in the level of total mercury in the 18 species of Alaska birds surveyed was not supported. We found interspecific differences with the Lesser Scaup (Aythya affinis), and the Black Scoter (Melanitta nigra), having the highest muscle tissue levels of THg. In general, THg mean levels were higher in muscle than in brain with the exceptions of the Bar-tailed Godwit and Northern Shoveler. Bone THg were highest in the Black Scoter. The mean values for THg in the species studied are unlikely to cause adverse reproductive or behavioral effects in the birds. PMID:16076480

Rothschild, Roger F N; Duffy, Lawrence K

2005-10-15

43

Spring-harvested game birds from the western James Bay region of northern Ontario, Canada: organochlorine concentrations in breast muscle.  

PubMed

Although studies have assessed organochlorine concentration in breast tissue (pectoral muscle) of fall-harvested game birds in Canada, data for spring-harvested game birds are limited, especially for remote sub-arctic areas. Taking into account that most traditional Aboriginal diets include a large number of spring-harvested game birds, there is a need to assess organochlorine concentration in spring-harvested water birds with respect to suitability for human consumption. We examined organochlorine concentrations in breasts of 20 mallard ducks (Anas platyrhynchos), 20 northern pintails (A. acuta), 21 Canada geese (Branta canadensis interior), and 20 lesser snow geese (Chen caerulescens caerulescens) harvested in the spring; summer-harvested shorebirds (godwits; Limosa spp.) were also assessed as these water birds are an important part of the game bird harvest for First Nation Cree of the western James Bay region of Ontario, Canada. The most frequently detected organochlorines in striated (pectoral) muscle were SigmaPCBs (sum of 14 congeners [CBs]) and SigmaDDT (sum of DDE and DDT) followed by SigmaCHL (sum of oxy-chlordane, cis- and trans-nonachlor) and hexachlorobenzene with beta-hexachlorocyclohexane being the least frequently detected. For organochlorines that had < or =70% of the samples with detectable concentrations of an organochlorine (i.e., CBs 105, 128, 156, 170, 180, 183, cis-nonachlor, DDT, and mirex), log-linear contingency modelling revealed that the dabbling ducks had significantly more than expected detectable concentrations of most organochlorines; by contrast, geese and shorebirds had significantly less than expected detectable concentrations of most organochlorines. ANOVA for organochlorines with frequency of detection > or =70% (i.e., Aroclor 1260, SigmaPCBs, CBs 118, 138, 153, 187, DDE, hexachlorobenzene, oxy-chlordane and trans-nonachlor) revealed significant differences between bird species: Breast tissue in snow geese contained significantly less organochlorines than Canada geese (Aroclor 1260, CBs 118, 138, and 153) and godwits (Aroclor 1260, CBs 138, 153); mallards had significantly higher concentrations compared to godwits (DDE, trans-nonachlor, and SigmaCHLs), Canada geese (oxy-chlordane and SigmaCHLs), and snow geese (oxy-chlordane, trans-nonachlor, SigmaCHLs); and pintails had elevated levels compared to snow geese (CB 153, oxy-chlordane, trans-nonachlor, and SigmaCHLs) and Canada geese (oxy-chlordane). However, none of the samples analyzed in the present study exceeded the consumption guideline for organochlorines in fish or poultry with most samples being orders of magnitude less than the consumption guideline even when compared to maxima. Thus, the present spring-harvested-game bird study supports previous studies of fall-harvested game birds that contend that pectoral muscle portions are safe to eat. Nevertheless, skin and fat associated with the breast muscle may be another matter. PMID:17675140

Tsuji, Leonard J S; Martin, Ian D; Martin, Emily S; LeBlanc, Alain; Dumas, Pierre

2007-10-15

44

Supplement 3, Authors: A To I  

E-print Network

Prof. Al- fonso Lamas. Montevideo. Limosa.?Limosa. Orgaan der Club van Neder- lansche Vogelkundigen. Wageningen. Live Stock Bull., Sydney.?Live Stock Bulletin. Sydney. MSN.?MSN. Monthly Science News. London. Manadsblad Skand. Kreatursf... Prof. Al- fonso Lamas. Montevideo. Limosa.?Limosa. Orgaan der Club van Neder- lansche Vogelkundigen. Wageningen. Live Stock Bull., Sydney.?Live Stock Bulletin. Sydney. MSN.?MSN. Monthly Science News. London. Manadsblad Skand. Kreatursf...

Doss, Mildred A.; Humphrey, Judith H.

1955-01-01

45

Periphyton grazing by Amnicolalimosa: An enclosure-exclosure experiment  

Microsoft Academic Search

An enclosure-exclosure experiment was performed in Nonquit Pond, Rhode Island to test the effect of grazing by Amnicola limosa (Say) (Gastropoda) upon lentic periphyton. Periphyton from enclosures with A. limosa had higher organic content in May and July, and lower standing crops in May, July, August, and September than periphyton from exclosures without A. limosa. Small diatom (< 18 ?m

David H. Kesler

1981-01-01

46

Shorebird use of an exposed sandy beach in southern California  

NASA Astrophysics Data System (ADS)

Frequent morning surveys of birds were conducted on 1 km of beach in southern California to investigate shorebird use of an exposed sandy beach. The overall mean abundance (98.6 individuals km -1), estimated biomass (9.6 kg km -1), and species richness (5.5 species km -1) of shorebirds observed were very high for a sandy beach in the temperate zone. Eight species, sanderling ( Calidris alba), semipalmated plover ( Charadrius semipalmatus), marbled godwit ( Limosa fedoa), black-bellied plover ( Pluvialis squatarola), western sandpiper ( Calidris mauri), willet ( Catoptrophorus semipalmatus), surfbird ( Aphriza virgata), and whimbrel ( Numenius phaeopus), occurred in overall mean abundances >1 bird km -1 and accounted for 97% of the abundance and biomass of shorebirds. Sanderlings were the most abundant shorebird every year (64% of individuals and 35% of the biomass). Different species of abundant shorebirds exhibited distinct patterns of use of beach habitat, including fall, spring, and winter peaks in abundance. Temporal variation in shorebird use on seasonal and interannual scales was associated with migration patterns, and also with habitat availability and condition. Seasonal variation in monthly mean abundance and estimated biomass of shorebirds varied over more than an order of magnitude and followed a similar pattern in each year, reaching maxima in the fall or winter (161-280 individuals km -1 and 15.4-23.9 kg km -1) and minima in May or June (3-11 individuals km -1 and 0.8-2.2 kg km -1). A minor peak in shorebird abundance and biomass coinciding with spring migration was observed in April of most years. The number of species of shorebirds observed in individual surveys ranged from 0 to 11 species km -1 and was positively and significantly correlated with abundance. Monthly mean species richness and the total species observed monthly followed similar seasonal patterns, ranging from annual maxima of 7.4-9.1 and 12-17 species km -1 between August and October to minima of 0.8-2.1 and 2-8 species km -1, respectively, during June. In contrast, species turnover was lowest (1.1-1.7) in October and November, and generally highest (2-4) during early summer (June). The amount of sandy intertidal habitat available to shorebirds on the transect was estimated using sand elevations and predicted tide heights. In the fall and winter, the abundance of shorebirds was significantly and positively correlated with tide height, possibly reflecting feeding opportunities and high tide refuge effects during the highest tides. In the spring when sand levels were low, the abundance of shorebirds was negatively correlated with tide height. Prey availability, beach condition and the local availability, and condition of alternative foraging habitats may influence those relationships. Interannual variations in shorebird use and beach condition were observed in the course of the study. During an El Nino Southern Oscillation (ENSO) event (1997-1998), the extent of sandy habitat was greatly reduced and intertidal habitat was mostly converted to rocky substrate. The overall abundance of shorebirds and the mean abundance of some common species (e.g. sanderling) were depressed, and an uncommon species (surfbird, A. virgata) was unusually abundant during the ENSO event. In summary, the results suggest that sandy beaches are important habitat for many species of shorebirds, particularly in areas where alternative coastal foraging habitats, such as coastal wetlands, have become scarce. Understanding the dynamics of and threats to exposed sandy beaches may be increasingly important for shorebird conservation in many coastal regions.

Hubbard, David M.; Dugan, Jenifer E.

2003-10-01

47

On-Site Wastewater Treatment Systems: Septic Tank/Soil Absorption Field (Spanish)  

E-print Network

hasta la superficie del suelo y protegerse con una buena tapa. Estos tubos ascendentes facilitan mucho el mantenimiento del tanque. Textura del suelo: Hay tres texturas de suelo: arenosa, limosa y arcillosa. La textura del suelo afecta la rapidez con la... hasta la superficie del suelo y protegerse con una buena tapa. Estos tubos ascendentes facilitan mucho el mantenimiento del tanque. Textura del suelo: Hay tres texturas de suelo: arenosa, limosa y arcillosa. La textura del suelo afecta la rapidez con la...

Lesikar, Bruce J.; Enciso, Juan

2000-10-13

48

Irrigation Monitoring with Soil Water Sensors (Spanish)  

E-print Network

1.9 (16) 0.8 (7) 1.1 (9) Marga arenosa 2.5 (21) 1.1 (9) 1.4 (12) Marga 3.2 (27) 1.4 (12) 1.8 (15) Marga limosa 3.6 (30) 1.8 (15) 1.8 (15) Marga arcillo-arenosa 4.3 (36) 2.4 (20) 1.9 (16) Arcilla arenosa 3.8 (32) 2.2 (18) 1.7 (14) Marga arcillosa 3....5 (29) 2.2 (18) 1.3 (11) Marga arcillo-limosa 3.4 (28) 1.8 (15) 1.6 (13) Arcilla limosa 4.8 (40) 2.4 (20) 2.4 (20) Arcilla 4.8 (40) 2.6 (22) 2.2 (18) *Los n?meros en par?ntesis representan el contenido volum?trico de humedad en porcentajes. Fuente...

Enciso, Juan; Porter, Dana; Peries, Xavier

2007-07-25

49

Food habits, habitat, distribution, numbers, and subspecies of sandhill cranes wintering in southern Texas  

E-print Network

through October, but by eazly November had. i'ruited, and was decaying. Lush stands of arrowhead, sephyr-l1ly, mud-planta1n (Heteranthera limosa), and senna (Cassia sp. ) became evident during late October and early November. Semi- aquatic species... through October, but by eazly November had. i'ruited, and was decaying. Lush stands of arrowhead, sephyr-l1ly, mud-planta1n (Heteranthera limosa), and senna (Cassia sp. ) became evident during late October and early November. Semi- aquatic species...

Guthery, Frederick Stewart

2012-06-07

50

On-Site Wastewater Treatment Systems: Sand Filters (Spanish)  

E-print Network

peque?o reduce la velocidad del movimiento del agua y Las aguas negras que se aplican al filtro de arena deben ser pretratadas, como en una fosa s?ptica. Figura 2: Un filtro de arena. Conducto el?ctrico Material filtrante Arena limosa Conjunto de v... peque?o reduce la velocidad del movimiento del agua y Las aguas negras que se aplican al filtro de arena deben ser pretratadas, como en una fosa s?ptica. Figura 2: Un filtro de arena. Conducto el?ctrico Material filtrante Arena limosa Conjunto de v...

Lesikar, Bruce J.; Enciso, Juan

2000-10-13

51

Texas Rice, Volume 1, Number 8  

E-print Network

of Agriculture’s Agricultural Re- search Service, a substantial number have been evalu- ated for allelopathic effects on aquatic weeds-about 12,000 for ducksalad [Heteranthera limosa (Sw.) Willd] and around 5,000 for redstem (Ammannia coccinea Rottb.). In field... of Agriculture’s Agricultural Re- search Service, a substantial number have been evalu- ated for allelopathic effects on aquatic weeds-about 12,000 for ducksalad [Heteranthera limosa (Sw.) Willd] and around 5,000 for redstem (Ammannia coccinea Rottb.). In field...

52

New, known and unidentified species of Eulimdana (Nematoda): additional information on biologically unusual filarioids of charadriiform birds  

Microsoft Academic Search

Eulimdana spp. were found in 13 of 32 species of charadriiform birds from North America and Iceland; 88 of 636 adult birds and seven\\u000a of 72 juvenile birds harboured infections. Described are: E. andersoni n. sp. from Chlidonias niger; E. metcalforum n. sp. from Sterna hirundo; E. sonini n. sp. from Charadrius hiaticula; E. wongae n. sp. from Limosa fedoa;

Cheryl M. Bartlett

1992-01-01

53

General Descriptions of Major Wetland Plant Communities in the upper portion of the Flathead Subbasin  

E-print Network

), beaked sedge (Carex utriculata), inflated sedge (Carex vesicaria), and awned sedge (Carex atherodes). Wet of the constituent species. Slender sedge #12;(Carex lasiocarpa), Buxbaum's sedge (Carex buxbaumii), and mud sedge (Carex limosa) are three sedges that can dominate portions of fens and sedge meadows. Marshes

54

Structure, dynamics and production of the benthic fauna in Lake Manitoba  

Microsoft Academic Search

The structure and diversity, including seasonal variation, and the energy budget of the benthic fauna in southern Lake Manitoba were studied and related to physical and chemical properties of the water and sediment. A total of 47 taxa were identified but 90 percent of individuals were represented by seven taxa (Candona rawsoni, Cytheromorpha fuscata, Pisidium spp., Amnicola limosa, Harnischia curtilamellata,

Claudiu Tudorancea; Roger H. Green; Judith Huebner

1979-01-01

55

Review of new world hagfishes of the genus Myxine  

E-print Network

of230 and 175 mm, respectively. Hermaphroditism is often found in individuals ofM. hubbsi, M. limosa specimens to state with certainty whether or not hermaphroditism occurs among them. Great variation- fishes, the latest by us in a series on the family Myxinidae begun by Carl L. Hubbs (deceased), includes

56

Limicolen-Vorkommen an der westafrikanischen Küste auf der Banc d'Arguin (Mauretanien)  

Microsoft Academic Search

Zusammenfassung 1.Neben den Lagunen der Küste Marokkos und dem Tal des Senegal stellen die Watten und Inseln der Banc d'Arguin ein drittes wichtiges Ruhegebiet für Limicolen in West-und Nordwestafrika dar, das vor allem von Arten mit enger Bindung an das Meer aufgesucht wird:Calidris alpina, Calidris canutus, Crocethia alba, Limosa lapponica, Numenius phaeopus undArenaria interpres.2.Außer eigenen Daten im Mai 1967 konnten

Wolfgang von Westernhagen

1968-01-01

57

Kulturverfahren zur Bestimmung der Salz- und Über-flutungsverträglichkeit von Puccinellia spp. (Gramineae)  

Microsoft Academic Search

In the ecology ofPuccinellia species (P. maritima, P. distans, P. retroflexa andP. limosa of the German flora described to date) two environmental factors seem to be very important: the salinity of the soil or of the tidal sea water and, especially in regard toP. maritima, the periodical inundation during the tidal cycle. The latter species forms an important community (Puccinellietum

K. von Weihe; G. Dreyling

1970-01-01

58

Methane emissions from an alpine fen in central Switzerland  

Microsoft Academic Search

Methane emissions and below ground methane pore water concentrations were determined in an alpine fen at 1,915 m a.s.l. in\\u000a central Switzerland. The fen represented an acidic (pH 4.5–4.9), nutrient-poor to mesotrophic habitat dominated by Carex limosa, Carex rostrata, Trichophorum caespitosum and Sphagnum species. From late fall to late spring the fen was snow-covered. Throughout winter the temperatures never dropped below

Susanne Liebner; Simon P. Schwarzenbach; Josef Zeyer

59

Structural identification of the beta-hydroxy fatty acid-based diester preen gland waxes of shorebirds.  

PubMed

The intact C33-C52 diester wax esters of the preen gland of the shorebirds Limosa lapponica, Pluvialis squatarola, and Pluvialis fulva were determined, using synthesized standards, to comprise predominantly C12-C16 beta-hydroxy fatty acids esterified with a C8-C18 fatty acid at the beta-hydroxy position and with predominantly C12-C20 fatty alcohols esterified at the carboxyl group. PMID:17960891

Rijpstra, W Irene C; Reneerkens, Jeroen; Piersma, Theunis; Damsté, Jaap S Sinninghe

2007-11-01

60

Environmental conditions in high mountain lakes containing toxic benthic cyanobacteria  

Microsoft Academic Search

In glacial lakes on an alpine pasture in Switzerland, benthic cyanobacteria produced microcystin, a cyclic hepatotoxic heptapeptide.\\u000a The cyanobacteria formed dense mats on sediments and submerged stones. The mats consisted mainly of Oscillatoria limosa, Phormidium\\u000a konstantinosum (= Oscillatoria tenuis) and Tychonema granulatum (= Oscillatoria granulata). In order to characterize the ecological\\u000a conditions of these cyanobacteria, nutrient concentrations were determined, and

Konstanze Mez; Kurt Hanselmann; Hans Rudolf Preisig

1998-01-01

61

Morphodynamically-based sediment budget in gravel-bed rivers: methodological problems (Invited)  

NASA Astrophysics Data System (ADS)

Estimation of the bed-material sediment budget from morphological changes has been adopted as an acceptable practice for gravel-bed rivers in which trends of morphological change persist for some considerable period. The qualification is important: co-located erosion and deposition within a survey interval biases the result. Another source of significant bias that has not generally been noted is the ';two-speed' nature of the fluvial sediment system by which sand moves through a reach much more quickly than gravel. Resident sand occurs in particular sedimentary environments (e.g., bar tail) and as cover sands - sometimes extensively so - in addition to forming gravel matrix. These materials are readily entrained during high flows and may constitute a large proportion of mobile sediment during flood. Unless explicitly accounted for in end-point assessments, they may significantly bias the gravel budget. Furthermore, they may easily be replaced during a single flood event, introducing the problem of co-located exchange. In Fraser River, British Columbia, a large gravel-bed river that appears suitable for sediment budget calculations by morphodynamic methods, an attempt is being made to understand this problem by mapping surficial sand using hyperspatial air photography and assessing its volume by application of a distribution of sand depths. The volume of these deposits may thereby be separately estimated and discounted in the assessments of changing gravel storage.

Church, M. A.

2013-12-01

62

Avian assemblages on altered grasslands  

USGS Publications Warehouse

Grasslands comprise 17% of the North American landscape but provide primary habitat for only 5% of native bird species. On the Great Plains, grasslands include an eastern component of tall grasses and a western component of short grasses, both of which have been regionally altered by removing native grazers, plowing sod, draining wetlands, and encouraging woody vegetation. As a group, populations of endemic bird species of the grasslands have declined more than others (including neotropical migrants) in the last quarter century. Individually, populations of the Upland Sandpiper and McCown’s Longspur have increased; the wetlands-associated Marbled Godwit and Wilson’s Phalarope appear stable; breeding ranges are shifting for the Ferruginous Hawk, Mississippi Kite, Short-eared Owl, Upland Sandpiper, Horned Lark, Vesper, Savannah, and Henslow’s sparrows, and Western Meadowlark; breeding habitats are disappearing locally for Franklin’s Gull, Dickcissel, Henslow’s and Grasshopper sparrows. Lark Bunting, and Eastern Meadowlark; and populations are declining throughout the breeding ranges for Mountain Plover, and Cassin’s and Clay-colored sparrows. Declines of these latter three species, and also the Franklin’s Gull, presumably are due to ecological phenomena on their respective wintering areas. Unlike forest species that winter in the neotropics, most birds that breed in the North American grasslands also winter on the continent and problems driving declines in grassland species are associated almost entirely with North American processes. Contemporary programs and initiatives hold promise for the conservation of breeding habitats for these birds. Ecological ignorance of wintering habits and habitats clouds the future of the endemic birds of grasslands, especially those currently experiencing widespread declines across breeding locales.

Knopf, Fritz L.

1994-01-01

63

The stability of aerobic granular sludge under 4-chloroaniline shock in a sequential air-lift bioreactor (SABR).  

PubMed

The aerobic granular sludge technology has a great potential in treatment of municipal wastewater and industrial wastewater containing toxic non-degradable pollutants. However, the formation and structural stability of aerobic granular sludge is susceptible to toxic shock. In the study, the effect of 4-chloroaniline (4-ClA) as a common toxic pollutant on the granular structure and performance was investigated, and the mechanism was revealed to provide more information on 4-ClA degradation with aerobic granular sludge process. The results showed that a 4-ClA shock at influent 200 mg L(-1) could cause the disintegration of aerobic granular sludge and decrease of the pollutant removal performance. The analysis of extracellular polymeric substances (EPS) within the mature and disintegrated granular sludge showed that the decrease of protein content in EPS, especially the components like Amide I 3-turn helix and ?-sheet structures and aspartate, was not good for the stability of aerobic granular sludge. The microbial community results demonstrated that the disappearance of dominant bacteria like Kineosphaera limosa or appearance like Acinetobacter, might contribute to the reduction of EPS and disintegration of aerobic granular sludge. PMID:23685649

Zhu, Liang; Lv, Mei-le; Dai, Xin; Zhou, Jia-heng; Xu, Xiang-yang

2013-07-01

64

[Temporal and spatial variation of shorebirds in Barra de Navidad lagoon, Jalisco, during three non-breeding seasons].  

PubMed

Resident and migratory shorebirds inhabit different kinds of wetlands such as lagoons, rivers and seashores among others. In recent years, these areas have been importantly affected by urban, agriculture and touristic activities, such as the Barra de Navidad lagoon, for which little information is available to support conservation programs. The aim of this work was to describe shorebirds temporal and spatial distribution in Barra de Navidad lagoon during three non-breeding seasons (1999-2000, 2006-2007 and 2008-2009). For this, monthly censuses were performed from November-April with the purpose of registering all the shorebirds species. We were able to identify 19 shorebirds species (three residents and 16 winter visitors), of which Charadrius wilsonia, Limosa fedoa and Tringa semipalmata were the most abundant. The greater number of species was registered for November, December and March of the first and third seasons. The greater number of individuals was registered when birds were feeding during low tides, mainly in December, January and February of the first and third seasons. At low tide, there was a great number of species and individuals in zone C. This area had muddy substrates that were exposed during low tides and were used to feed. Barra de Navidad lagoon provided suitable habitats for feeding and resting for resident and migratory birds. Twelve of the 19 species were considered as priority within the Mexican bird conservation strategy. However, these habitats are threatened by human activities performed in the nearby areas of the lagoon that may have negative consequences for the distribution, abundance and conservation of these species. PMID:23025100

Hernández, Salvador; Serrano, Sergio; Hernández, Xóchitl A; Robles, María Isabel

2012-09-01

65

Mechanisms of point bar growth and accretion in experimental bedload-dominated streams  

NASA Astrophysics Data System (ADS)

As channels migrate across their floodplains they erode their outer banks and create new floodplain on their inner bank via deposition of a point bar. While there has been considerable work on flow through bends and on erosion of the outer bank, there has been comparatively little study of the mechanisms of lateral point bar growth and accretion. We hypothesize that if slope and discharge are sufficient for meandering channels, meandering requires three additional conditions: (1) increased bank strength so that bar growth can keep pace with bank erosion; (2) overbank flows so the point bar can grow to the elevation of the floodplain; and (3) finer (suspendable) particles to allow the point bar to attach to the floodplain downstream of the bar apex. The first condition stems from experiments conducted with the same bed and bank material without sprouts that resulted in a braided morphology and observations of characteristics of meandering channels in the field. The second condition arises because sediment deposition to the elevation of the floodplain requires flow depth that exceeds the elevation of floodplain. The last condition emerges from the strong tendency for the downstream tail of point bars to form a ridge away from the inner bank and leave a trough where bedload sediment doesn't enter. These hypotheses are based on initial single bend experiments in a 3.7 m by 6.1 m flume with a slope of 0.005 that uses alfalfa sprouts to provide bank strength. New experiments are now underway using a 6.1 m wide and 16.5 m long flume with a valley slope of 0.004. The initial channel is set to 1.9 cm deep and 40 cm wide. As before, we have used alfalfa sprouts to increase the bank strength and reduce the bank erosion rate. The previous experiments consisted of two runs with 4 discharges ranging from the critical flow for the initiation of sediment transport to a flow double bankfull. In the experiments in the larger basin, we will use a two-stage hydrograph with a long-duration bankfull flow and a shorter-duration overbank flow. Our goal is to model a meandering gravel bedded stream, which puts particular emphasis on the availability of finer sediment to bridge the gap between the bar tail and the floodplain. Here we use two sediment types to represent gravel and sand. The model gravel was sand with a median size of 0.85 mm and a specific gravity of 2.66. We used plastic sediment with a median size of 370 microns and specific gravity of 1.5 as the model sand. The lower specific gravity allows the plastic to be re-entrained more easily than denser particles with the same settling velocity. We anticipate being able to develop four bends, with the lower ones evolving to cutoff. Initial experiments without plastic were able to connect the bar to the floodplain upstream of the bar apex but the trough remained downstream of the bar apex. Subsequent test runs with both plastic and sand showed that the plastic was able to deposit where the trough formed downstream of the bar apex.

Braudrick, C. A.; Leverich, G.; Dietrich, W. E.; Sklar, L.

2006-12-01

66

Constructing a Baseline Model of Alpine Wetlands of the Uinta Mountains, Utah, USA  

NASA Astrophysics Data System (ADS)

Alpine wetlands of the Uinta Mountains, northeastern Utah, contain a variety of groundwater-dependent ecosystems. Unlike their counterparts in other areas of the Rocky Mountains, these systems have been relatively unstudied. The Reader Lakes area on the southern slope of the range was selected for detailed study because of its variety of wetland plant communities, homogenous bedrock geology, and minimal human impact. The primary goal of this interdisciplinary study is to establish the functional links between the geomorphology and hydrogeology of these high mountain wetlands and their constituent plant communities. In addition to traditional field studies and water chemistry, geospatial technologies are being used to organize and analyze both field data (water chemistry and wetland vegetation) and archived multispectral imagery (2006 NAIP images). The hydrology of these wetlands is dominated by groundwater discharge and their surface is dominated by string-and-flark morphology of various spatial scales, making these montane wetlands classic patterned fens. The drainage basin is organized into a series of large-scale stair-stepping wetlands, bounded by glacial moraines at their lower end. Wetlands are compartmentalized by a series of large strings (roughly perpendicular to the axial stream) and flarks. This pattern may be related to small ridges on the underlying ground moraine and possibly modified by beaver activity along the axial stream. Small-scale patterning occurs along the margins of the wetlands and in sloping-fen settings. The smaller-scale strings and flarks form a complex; self-regulating system in which water retention is enhanced and surface flow is minimized. Major plant communities have been identified within the wetlands for example: a Salix planifolia community associated with the peaty strings; Carex aquatilis, Carex limosa, and Eriophorum angustifolium communities associated with flarks; as well as a Sphagnum sp.- rich hummocky transition zone between wetland and non-wetland areas. On-going analyses of water-chemistry data will be used to identify discrete water sources and to characterize the degree of horizontal and vertical water mixing within the system, as well as to help identify the biochemical requirements of the different plant communities. Results indicate that the chemical composition of the main creek reflects the accumulative effect that the peaty flarks have on the creek as it passes through the wetland system, with pH overall decreasing from 7.3 to 7.0, dissolved oxygen decreasing from 9400 to 8400 micrograms per liter and total dissolved solids increasing from 9 mg/L to 13 mg/L. String ground water is characterized by relatively high pH (ranging from 6.0 to 7.1), high oxidizing-reducing potential (ORP) (ranging from 50 mV to 180 mV), high dissolved oxygen (from 2500 ?g/L to 9600 ?g /L) while flark ground water has relatively lower pH (5.6 to 6.8), low oxidizing reducing potential (ORP) (ranging from -66 mV to 150 mV), low dissolved oxygen (from 900 ?g /L to 9000 ?g /L).

Matyjasik, M.; Ford, R. L.; Bartholomew, L. M.; Welsh, S. B.; Hernandez, M.; Koerner, D.; Muir, M.

2008-12-01