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Sample records for bar-tailed godwit limosa

  1. Contrasting extreme long-distance migration patterns in bar-tailed godwits Limosa lapponica

    USGS Publications Warehouse

    Battley, Phil F.; Warnock, Nils; Tibbitts, T. Lee; Gill, Robert E., Jr.; Piersma, Theunis; Hassell, Chris J.; Douglas, David C.; Mulcahy, Daniel M.; Gartrell, Brett D.; Schuckard, Rob; Melville, David S.; Riegen, Adrian C.

    2012-01-01

    Migrating birds make the longest non-stop endurance flights in the animal kingdom. Satellite technology is now providing direct evidence on the lengths and durations of these flights and associated staging episodes for individual birds. Using this technology, we compared the migration performance of two subspecies of bar-tailed godwit Limosa lapponica travelling between non-breeding grounds in New Zealand (subspecies baueri) and northwest Australia (subspecies menzbieri) and breeding grounds in Alaska and eastern Russia, respectively. Individuals of both subspecies made long, usually non-stop, flights from non-breeding grounds to coastal staging grounds in the Yellow Sea region of East Asia (average 10 060 ± SD 290 km for baueri and 5860 ± 240 km for menzbieri). After an average stay of 41.2 ± 4.8 d, baueri flew over the North Pacific Ocean before heading northeast to the Alaskan breeding grounds (6770 ± 800 km).Menzbieri staged for 38.4 ± 2.5 d, and flew over land and sea northeast to high arctic Russia (4170 ± 370 km). The post-breeding journey for baueri involved several weeks of staging in southwest Alaska followed by non-stop flights across the Pacific Ocean to New Zealand (11 690 km in a complete track) or stopovers on islands in the southwestern Pacific en route to New Zealand and eastern Australia. By contrast, menzbieri returned to Australia via stopovers in the New Siberian Islands, Russia, and back at the Yellow Sea; birds travelled on average 4510 ± 360 km from Russia to the Yellow Sea, staged there for 40.8 ± 5.6 d, and then flew another 5680–7180 km to Australia (10 820 ± 300 km in total). Overall, the entire migration of the single baueri godwit with a fully completed return track totalled 29 280 km and involved 20 d of major migratory flight over a round-trip journey of 174 d. The entire migrations of menzbieri averaged 21 940 ± 570 km, including 14 d of major migratory flights out of 154 d total. Godwits of both populations exhibit extreme flight performance, and bauerimakes the longest (southbound) and second-longest (northbound) non-stop migratory flights documented for any bird. Both subspecies essentially make single stops when moving between non-breeding and breeding sites in opposite hemispheres. This reinforces the critical importance of the intertidal habitats used by fuelling godwits in Australasia, the Yellow Sea, and Alaska.

  2. Midazolam as an adjunctive therapy for capture myopathy in Bar-tailed Godwits (Limosa lapponica baueri) with prognostic indicators.

    PubMed

    Ward, Janelle M; Gartrell, Brett D; Conklin, Jesse R; Battley, Phil F

    2011-10-01

    Capture myopathy is a complication of capture and handling in many species of birds and mammals. Muscular necrosis leads to ataxia, paralysis, and pain, whereas metabolic disturbances can result in death. We conducted an opportunistic clinical trial on Bar-tailed Godwits (Limosa lapponica baueri) that developed capture myopathy after a cannon-net capture in New Zealand in October 2008. We assessed the beneficial effects of midazolam, a benzodiazepine with the effects of anxiolysis, muscle relaxation, and sedation, in the adjunctive treatment of capture myopathy. Physical and biochemical parameters were analyzed retrospectively for their potential as indicators for survival until release. Birds (n=16) were treated with subcutaneous fluid therapy, a nonsteroidal anti-inflammatory (meloxicam), gavage feeding, and sling therapy twice daily. The treatment group (n=8) was treated twice daily with intramuscular midazolam injections, 1.5 mg/kg. Surviving godwits were released over 1-9 days, with 6 of 8 treated birds (75%) surviving to release, compared with 3 of 8 controls (38%). Inability to counteract weight loss in captivity was the most significant problem for both groups. Lack of waterproofing and predation were contributing causes of death for at least two godwits after release. Birds treated with midazolam showed subjective benefits including improved tolerance of handling and sling therapy. Clinical parameters (change in body mass, packed cell volume [PCV], plasma creatine kinase [CK], aspartate aminotransferase [AST], total protein, and uric acid [UA] over time) were not statistically different between groups, although peak average values for CK, AST, and UA were lower in the treatment group. Decline in body mass (%), PCV, final plasma UA, and peak plasma CK were the most useful prognostic indicators. Midazolam shows potential as an ancillary treatment for capture myopathy in birds and is worthy of continued study and use. PMID:22102663

  3. 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

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

    2011-01-01

    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.

  4. Geographic variation in morphology of Alaska-breeding Bar-tailed Godwits (Limosa lapponica) is not maintained on their nonbreeding grounds in New Zealand

    USGS Publications Warehouse

    Conklin, J.R.; Battley, Phil F.; Potter, M.A.; Ruthrauff, D.R.

    2011-01-01

    Among scolopacid shorebirds, Bar-tailed Godwits (Limosa lapponica) have unusually high intra- and intersexual differences in size and breeding plumage. Despite historical evidence for population structure among Alaska-breeding Bar-tailed Godwits (L. l. baueri), no thorough analysis, or comparison with the population's nonbreeding distribution, has been undertaken. We used live captures, field photography, museum specimens, and individuals tracked from New Zealand to describe geographic variation in size and plumage within the Alaska breeding range. We found a north-south cline in body size in Alaska, in which the smallest individuals of each sex occurred at the highest latitudes. Extent of male breeding plumage (proportion of nonbreeding contour feathers replaced) also increased with latitude, but female breeding plumage was most extensive at mid-latitudes. This population structure was not maintained in the nonbreeding season: morphometrics of captured birds and timing of migratory departures indicated that individuals from a wide range of breeding latitudes occur in each region and site in New Zealand. Links among morphology, phenology, and breeding location suggest the possibility of distinct Alaska breeding populations that mix freely in the nonbreeding season, and also imply that the strongest selection for size occurs in the breeding season. ?? 2011 The American Ornithologists' Union.

  5. Guts don't fly: Small digestive organs in obese Bar-tailed Godwits

    USGS Publications Warehouse

    Piersma, Theunis; Gill, R.E., Jr.

    1998-01-01

    We documented fat loads and abdominal organ sizes of Bar-tailed Godwits (Limosa lapponica baueri) that died after colliding against a radar dome on the Alaska Peninsula, most likely just after takeoff on a trans-Pacific flight of 11,000 km, and of birds of the same subspecies just before northward departure from New Zealand. We compared these data with data on body composition of godwits of the smaller lapponica subspecies obtained during a northward stopover in The Netherlands. As a consequence of high amounts of subcutaneous and intraperitoneal fat, and very small fat-free mass, Bar-tailed Godwits from Alaska had relative fat loads that are among the highest ever recorded in birds (ca. 55% of fresh body mass). Compared with northbound godwits from New Zealand, the Alaskan birds had very small gizzards, livers, kidneys, and guts. This suggests that upon departure, long-distance migrants dispense with parts of their 'metabolic machinery' that are not directly necessary during flight, and rebuild these organs upon arrival at the migratory destination.

  6. Hemispheric-scale wind selection facilitates bar-tailed godwit circum-migration of the Pacific

    USGS Publications Warehouse

    Gill, Robert E., Jr.; Douglas, David C.; Handel, Colleen M.; Tibbitts, T. Lee; Hufford, Gary; Piersma, Theunis

    2014-01-01

    The annual 29 000 km long migration of the bar-tailed godwit, Limosa lapponica baueri, around the Pacific Ocean traverses what is arguably the most complex and seasonally structured atmospheric setting on Earth. Faced with marked variation in wind regimes and storm conditions across oceanic migration corridors, individuals must make critical decisions about when and where to fly during nonstop flights of a week's duration or longer. At a minimum, their decisions will affect wind profitability and thus reduce energetic costs of migration; in the extreme, poor decisions or unpredictable weather events will risk survival. We used satellite telemetry to track the annual migration of 24 bar-tailed godwits and analysed their flight performance relative to wind conditions during three major migration legs between nonbreeding grounds in New Zealand and breeding grounds in Alaska. Because flight altitudes of birds en route were unknown, we modelled flight efficiency at six geopotential heights across each migratory segment. Birds selected departure dates when atmospheric conditions conferred the greatest wind assistance both at departure and throughout their flights. This behaviour suggests that there exists a cognitive mechanism, heretofore unknown among migratory birds, that allows godwits to assess changes in weather conditions that are linked (i.e. teleconnected) across widely separated atmospheric regions. Godwits also showed adaptive flexibility in their response not only to cues related to seasonal changes in macrometeorology, such as spatial shifting of storm tracks and temporal periods of cyclogenesis, but also to cues associated with stochastic events, especially at departure sites. Godwits showed limits to their response behaviours, however, especially relative to rapidly developing stochastic events while en route. We found that flight efficiency depended significantly upon altitude and hypothesize that godwits exhibit further adaptive flexibility by varying flight altitude en route to optimize flight efficiency.

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

    PubMed

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

    2007-06-01

    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

  8. Site selection and resource depletion in black-tailed godwits Limosa l. limosa eating rice during northward migration.

    PubMed

    Loureno, Pedro M; Mandema, Freek S; Hooijmeijer, Jos C E W; Granadeiro, Jos P; Piersma, Theunis

    2010-05-01

    1. During migratory stopovers, animals are under strong time stress and need to maximize intake rates. We examine how foragers react to resource depletion by studying the foraging ecology and foraging site selection of black-tailed godwits Limosa l. limosa staging in rice fields during their northward migration stopover (January-March 2007). 2. We analysed godwit abundance and foraging behaviour, sampled the availability of rice in the fields and used the functional response model to predict the giving-up density (GUD) of rice kernels when godwits should give up a rice field. Sightings of individually colour-marked birds were used to verify whether individuals moving between rice fields confirmed the predicted GUD. 3. Black-tailed godwit intake rates at different rice densities fitted Holling's functional response curve. The predicted GUD of rice necessary to balance allometric estimates of daily energy expenditure (DEE) and measured time budgets were confirmed by GUD measured in the field. 4. Individually marked birds moved towards rice fields with higher rather than lower rice densities more often than randomly expected. These birds increased the measured intake rates after this move. 5. Godwit foraging caused a decrease in the rice density of individual fields during the stopover period. Despite this, overall intake rates remained constant as godwits reacted to resource depletion by moving to a new foraging site as soon as their intake rate falls below the required levels to achieve DEE. PMID:20070431

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

    PubMed Central

    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

    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

  10. Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit.

    PubMed

    Yosefi, Sara; Hen, Gideon; Rosenblum, Charles I; Cerasale, David J; Beaulieu, Michaël; Criscuolo, Francois; Friedman-Einat, Miriam

    2010-10-01

    Unsuccessful attempts to identify the leptin gene in birds are well documented, despite the characterization of its receptor (LEPR). Since leptin and LEPR have poor sequence conservation among vertebrates, we speculated that a functional assay should represent the best way to detect leptin in birds. Using a leptin bioassay that is based on activation of the chicken LEPR in cultured cells, blood samples from wild birds with extreme seasonal variation in voluntary food intake and fat deposition (Adélie penguins and bar-tailed godwits) were tested for leptin activity. In these experiments, blood samples collected during the pre-incubation and the chick-rearing periods of Adélie penguins, and during the migratory flight and refueling stages of bar-tailed godwits, were found to contain no detectable leptin activity, while the sensitivity of the assay to activation by human blood samples from donor subjects representing a variety of body mass indices and fat contents was clearly demonstrated. These results suggest that in birds, an alternative control mechanism to that of mammals operates in the communication between the body fat tissues and the central control on energy homeostasis. PMID:20675300

  11. Lead poisoning of a marbled godwit

    USGS Publications Warehouse

    Locke, L.N.; Smith, M.R.; Windingstad, R.M.; Martin, S.J.

    1991-01-01

    A thin adult female marbled godwit (Limosa fedoa) found dead at Benton Lake National Wildlife Refuge, Montana, was found to have 17 ingested lead shot in its gizzard. Its liver contained 51.7 ppm lead (wet weight). Based on these necropsy findings a diagnosis of lead poisoning was made.

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

    SciTech Connect

    Denker, E.; Buethe, A.

    1995-12-01

    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.

  13. Phenotype-limited distributions: short-billed birds move away during times that prey bury deeply.

    PubMed

    Duijns, Sjoerd; van Gils, Jan A; Smart, Jennifer; Piersma, Theunis

    2015-06-01

    In our seasonal world, animals face a variety of environmental conditions in the course of the year. To cope with such seasonality, animals may be phenotypically flexible, but some phenotypic traits are fixed. If fixed phenotypic traits are functionally linked to resource use, then animals should redistribute in response to seasonally changing resources, leading to a 'phenotype-limited' distribution. Here, we examine this possibility for a shorebird, the bar-tailed godwit (Limosa lapponica; a long-billed and sexually dimorphic shorebird), that has to reach buried prey with a probing bill of fixed length. The main prey of female bar-tailed godwits is buried deeper in winter than in summer. Using sightings of individually marked females, we found that in winter only longer-billed individuals remained in the Dutch Wadden Sea, while the shorter-billed individuals moved away to an estuary with a more benign climate such as the Wash. Although longer-billed individuals have the widest range of options in winter and could therefore be selected for, counterselection may occur during the breeding season on the tundra, where surface-living prey may be captured more easily with shorter bills. Phenotype-limited distributions could be a widespread phenomenon and, when associated with assortative migration and mating, it may act as a precursor of phenotypic evolution. PMID:26543585

  14. Sex-specific winter distribution in a sexually dimorphic shorebird is explained by resource partitioning

    PubMed Central

    Duijns, Sjoerd; van Gils, Jan A; Spaans, Bernard; ten Horn, Job; Brugge, Maarten; Piersma, Theunis

    2014-01-01

    Sexual size dimorphism (SSD) implies correlated differences in energetic requirements and feeding opportunities, such that sexes will face different trade-offs in habitat selection. In seasonal migrants, this could result in a differential spatial distribution across the wintering range. To identify the ecological causes of sexual spatial segregation, we studied a sexually dimorphic shorebird, the bar-tailed godwit Limosa lapponica, in which females have a larger body and a longer bill than males. With respect to the trade-offs that these migratory shorebirds experience in their choice of wintering area, northern and colder wintering sites have the benefit of being closer to the Arctic breeding grounds. According to Bergmann's rule, the larger females should incur lower energetic costs per unit of body mass over males, helping them to winter in the cold. However, as the sexes have rather different bill lengths, differences in sex-specific wintering sites could also be due to the vertical distribution of their buried prey, that is, resource partitioning. Here, in a comparison between six main intertidal wintering areas across the entire winter range of the lapponica subspecies in northwest Europe, we show that the percentage of females between sites was not correlated with the cost of wintering, but was positively correlated with the biomass in the bottom layer and negatively with the biomass in the top layer. We conclude that resource partitioning, rather than relative expenditure advantages, best explains the differential spatial distribution of male and female bar-tailed godwits across northwest Europe. PMID:25505527

  15. Phenotype-limited distributions: short-billed birds move away during times that prey bury deeply

    PubMed Central

    Duijns, Sjoerd; van Gils, Jan A.; Smart, Jennifer; Piersma, Theunis

    2015-01-01

    In our seasonal world, animals face a variety of environmental conditions in the course of the year. To cope with such seasonality, animals may be phenotypically flexible, but some phenotypic traits are fixed. If fixed phenotypic traits are functionally linked to resource use, then animals should redistribute in response to seasonally changing resources, leading to a ‘phenotype-limited’ distribution. Here, we examine this possibility for a shorebird, the bar-tailed godwit (Limosa lapponica; a long-billed and sexually dimorphic shorebird), that has to reach buried prey with a probing bill of fixed length. The main prey of female bar-tailed godwits is buried deeper in winter than in summer. Using sightings of individually marked females, we found that in winter only longer-billed individuals remained in the Dutch Wadden Sea, while the shorter-billed individuals moved away to an estuary with a more benign climate such as the Wash. Although longer-billed individuals have the widest range of options in winter and could therefore be selected for, counterselection may occur during the breeding season on the tundra, where surface-living prey may be captured more easily with shorter bills. Phenotype-limited distributions could be a widespread phenomenon and, when associated with assortative migration and mating, it may act as a precursor of phenotypic evolution. PMID:26543585

  16. Absolute consistency: individual versus population variation in annual-cycle schedules of a long-distance migrant bird.

    PubMed

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

    2013-01-01

    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

  17. Inorganic and organic contaminants in Alaskan shorebird eggs.

    PubMed

    Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

    2016-05-01

    Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are relatively free of most contaminants and that contaminant concentrations are below levels (except potentially strontium) that would likely affect the survival of individuals and consequently regulate the species at the population level. PMID:27059035

  18. Extreme endurance flights by landbirds crossing the Pacific Ocean: Ecological corridor rather than barrier?

    USGS Publications Warehouse

    Gill, R.E., Jr.; Tibbitts, T.L.; Douglas, D.C.; Handel, C.M.; Mulcahy, D.M.; Gottschalck, J.C.; Warnock, N.; McCaffery, B.J.; Battley, Phil F.; Piersma, Theunis

    2009-01-01

    Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes. We used satellite telemetry to track the southward flights of bar-tailed godwits (Limosa lapponica baueri), shorebirds whose breeding and non-breeding areas are separated by the vast central Pacific Ocean. Seven females with surgically implanted transmitters flew non-stop 8117-11680km (10153??1043 s.d.) directly across the Pacific Ocean; two males with external transmitters flew non-stop along the same corridor for 7008-7390km. Flight duration ranged from 6.0 to 9.4 days (7.8??1.3 s.d.) for birds with implants and 5.0 to 6.6 days for birds with externally attached transmitters. These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility. Predicted changes in climatic systems may affect survival rates if weather conditions at their departure hub or along the migration corridor should change. We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators. ?? 2008 The Royal Society.

  19. Extreme endurance flights by landbirds crossing the Pacific Ocean: ecological corridor rather than barrier?

    PubMed Central

    Gill, Robert E.; Tibbitts, T. Lee; Douglas, David C.; Handel, Colleen M.; Mulcahy, Daniel M.; Gottschalck, Jon C.; Warnock, Nils; McCaffery, Brian J.; Battley, Philip F.; Piersma, Theunis

    2008-01-01

    Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes. We used satellite telemetry to track the southward flights of bar-tailed godwits (Limosa lapponica baueri), shorebirds whose breeding and non-breeding areas are separated by the vast central Pacific Ocean. Seven females with surgically implanted transmitters flew non-stop 8117–11 680 km (10 153±1043 s.d.) directly across the Pacific Ocean; two males with external transmitters flew non-stop along the same corridor for 7008–7390 km. Flight duration ranged from 6.0 to 9.4 days (7.8±1.3 s.d.) for birds with implants and 5.0 to 6.6 days for birds with externally attached transmitters. These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility. Predicted changes in climatic systems may affect survival rates if weather conditions at their departure hub or along the migration corridor should change. We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators. PMID:18974033

  20. Pair bonds: arrival synchrony in migratory birds.

    PubMed

    Gunnarsson, T G; Gill, J A; Sigurbjörnsson, T; Sutherland, W J

    2004-10-01

    Synchronous arrival of pairs of migratory birds at their breeding grounds is important for maintaining pair bonds and is achieved by pairs that remain together all year round. Here we show that arrival is also synchronized in paired individuals of a migratory shorebird, the black-tailed godwit (Limosa limosa islandica), even though they winter hundreds of kilometres apart and do not migrate together. The mechanisms required to achieve this synchrony and prevent 'divorce' illustrate the complexity of migratory systems. PMID:15470417

  1. Sweet salvation.

    PubMed

    Bates, Jane

    2016-04-20

    A bar-tailed godwit, I thought, feeling rather smug. I was photographing wading birds at the nearby salt marshes, and was very pleased with myself, not only for recognising the creature, but for getting some reasonable pictures. I also saw a flock of migrant geese and some lapwings, so altogether it was a satisfying trip. PMID:27097190

  2. Individual specialization in a shorebird population with narrow foraging niche

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    Individual specialization in resource use is a widespread driver for intra-population trait variation, playing a crucial evolutionary role in free-living animals. We investigated the individual foraging specialization of Black-tailed Godwits (Limosa limosa islandica) during the wintering period. Godwits displayed distinct degrees of individual specialization in diet and microhabitat use, indicating the presence of both generalist and specialist birds. Females were overall more specialist than males, primarily consuming polychaetes. Specialist males consumed mainly bivalves, but some individuals also specialized on gastropods or polychaetes. Sexual dimorphism in bill length is probably important in determining the differences in specialization, as longer-billed individuals have access to deep-buried polychaetes inaccessible to most males. Different levels of specialization within the same sex, unrelated to bill length, were also found, suggesting that mechanisms other traits are involved in explaining individual specialization. Godwits specialized on bivalves achieved higher intake rates than non-specialist birds, supporting the idea that individual foraging choices or skills result in different short-term payoffs within the same population. Understanding whether short-term payoffs are good indicators of long-term fitness and how selection operates to favour the prevalence of specialist or generalist godwits is a major future challenge.

  3. Effects of management practices on grassland birds: Marbled Godwit

    USGS Publications Warehouse

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

    1998-01-01

    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.

  4. Evidence of species-specific detoxification processes for trace elements in shorebirds.

    PubMed

    Lucia, Magali; Bocher, Pierrick; Cosson, Richard P; Churlaud, Carine; Bustamante, Paco

    2012-11-01

    This study investigated sub-lethal effects and detoxification processes activated in free-ranging Red Knots (RKs) (Calidris canutus) from the Pertuis Charentais on the Atlantic coast of France, and compared the results with previous data obtained on another shorebird species, the Black-tailed Godwit (Limosa limosa). The concentrations of 13 trace elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were assessed in the liver, kidneys, muscle and feathers. Stable isotope analyses of carbon and nitrogen were carried out to determine whether differences in diet explained variations in elemental uptake. The mRNA expression of relevant genes (cytochrome c oxidase 1, acetyl-CoA carboxylase, Cu/Zn and Mn superoxide dismutase, catalase, metallothionein, malic enzyme), antioxidant enzyme activities (catalase, glutathione peroxidase (GPx), superoxide dismutase), and metallothionein (MT) levels were investigated to shed light on trace element detoxification and toxic effects. Although Red Knots were characterized by elevated As and Se concentrations which were potentially toxic, most elements were usually below toxicity threshold levels. The results strongly suggested a dietary specialization of Red Knots, with individuals feeding on higher trophic status prey experiencing higher As, Hg and Se burdens. Red Knots and Godwits also showed discrepancies in elemental accumulation and detoxification processes. Higher As and Se concentrations in Red Knots enhanced catalase gene expression and enzyme activity, while Godwits had higher Ag, Cu, Fe and Zn levels and showed higher MT production and GPx activity. The results strongly suggest that detoxification pathways are essentially trace element- and species-specific. PMID:23001427

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

    PubMed Central

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

    2012-01-01

    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

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

    PubMed

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

    2002-12-01

    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

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

    PubMed

    Mendoza, Luis Francisco; Carmona, Roberto

    2013-03-01

    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

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

    PubMed

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

    2014-01-01

    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

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

    PubMed Central

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

    2014-01-01

    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

  10. Rapid changes in phenotype distribution during range expansion in a migratory bird

    PubMed Central

    Gunnarsson, Tmas Grtar; Sutherland, William J.; Alves, Jos A.; Potts, Peter M.; Gill, Jennifer A.

    2012-01-01

    The capacity of species to track changing environmental conditions is a key component of population and range changes in response to environmental change. High levels of local adaptation may constrain expansion into new locations, while the relative fitness of dispersing individuals will influence subsequent population growth. However, opportunities to explore such processes are rare, particularly at scales relevant to species-based conservation strategies. Icelandic black-tailed godwits, Limosa limosa islandica, have expanded their range throughout Iceland over the last century. We show that current male morphology varies strongly in relation to the timing of colonization across Iceland, with small males being absent from recently occupied areas. Smaller males are also proportionately more abundant on habitats and sites with higher breeding success and relative abundance of females. This population-wide spatial structuring of male morphology is most likely to result from female preferences for small males and better-quality habitats increasing both small-male fitness and the dispersal probability of larger males into poorer-quality habitats. Such eco-evolutionary feedbacks may be a key driver of rates of population growth and range expansion and contraction. PMID:21715406

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

    PubMed Central

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

    2013-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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 (δ13C) and nitrogen (δ15N) 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  15. When Siberia came to the Netherlands: The response of continental black-tailed godwits to a rare spring weather event

    USGS Publications Warehouse

    Senner, Nathan R.; Verhoeven, Mo A.; Abad-Go´mez, Jose´ M.; Gutie´rrez, Jorge S.; Hooijmeijer, Jos C. E. W.; Kentie, Rosemarie; Masero, Jose´ A.; Tibbitts, T. Lee; Piersma, Theunis

    2015-01-01

    This suggests that populations with continued access to food, behavioural flexibility and time to dissipate the costs of the event can likely withstand the consequences of an extreme weather event. For populations constrained in one of these respects, though, extreme events may entail extreme ecological consequences.

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

    USGS Publications Warehouse

    Hooijmeijer, Jos C. E. W.; Gill, Robert E., Jr.; 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

    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.

  17. 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)

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

    2013-12-01

    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.

  18. Consumption of benthic fauna by carnivorous birds in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Scheiffarth, G.; Nehls, G.

    1997-12-01

    Consumption by carnivorous birds was estimated for the Sylt-Rømø tidal inlet in the northern part of the Wadden Sea, as well as the subarea Königshafen, a small, tidal bay. The bird community of the Sylt-Rømø Wadden Sea was dominated by Dunlin (35% of all birds counted), Eider (9%), Oystercatcher (8%), Knot (8%), and Shelduck (7%). The community in the Königshafen was dominated by Eider (20%), Knot (17%), Bar-tailed Godwit (17%), Dunlin (13%), and Oystercatcher (8%). Annual consumption was estimated at 3.4 g AFDW · m-2 · year-1 for the entire Sylt-Rømø Wadden Sea and 19.2 g AFDW · m-2 · year-1 for the Königshafen. Restricting the calculations to the intertidal area resulted in a consumption of 8.7 g AFDW · m-2 · year-1 for the Sylt-Rømø Wadden Sea and 17.6 g AFDW · m-2 · year-1 for the Königshafen. In the two areas, consumption was dominated by the Eider with 37% and 60% of the total consumption, respectively. In comparison to the western parts of the Wadden Sea the seasonal pattern of consumption as well as species composition differed, most probably as an effect of different climatic conditions, whereas annual consumption on intertidal flats seems to be in the same order of magnitude. On average, 15 25% of the mean annual macrozoobenthic biomass seems to be taken by carnivorous birds in the Wadden Sea, which is in the same order of magnitude as in other northern temperate estuarine areas.

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

    PubMed

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

    2007-11-01

    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

  20. [The life cycle of Plagiorchis neomidis Brendow, 1970, digenean parasite of Neomys fodiens in the Pyrénées. Chronobiology of cercarial emergence (author's transl)].

    PubMed

    Theron, A

    1976-01-01

    The first host in the life cycle of Plagiorchis neomidis in the Pyrenees is the Mollusc Radix limosa var, glacialis. The cercariae encyst in the aquatic larvae of the Insect Sialis lutaria (Megaloptera). The adult parasite is found in the rectum of Neomys fodiens. The chetotaxy and the rhythm of cercarial emergence are described in detail as is the development of the metacercaria in its second intermediate host. Comparison of the life cycle of P. neomidis in the Pyrenees with that described in Germany demonstrates differences in the biology at both larval and adult stage. PMID:984664

  1. Passive internal dispersal of insect larvae by migratory birds

    PubMed Central

    Green, Andy J; Snchez, Marta I

    2005-01-01

    It has long been assumed that the resistant eggs of many zooplankton are able to survive passage through the gut of migratory waterbirds, thus facilitating their dispersal between isolated aquatic habitats. We present the first evidence that such passive internal transport within birds may be relevant for insect populations. In three out of six faecal samples from black-tailed Godwits on autumn migration in southwest Spain, we found larvae of the chironomid Chironomus salinarius which had survived gut passage. Although adult chironomids can fly, they are likely to disperse greater distances when transported as larvae via birds. In insects with discrete generations, such passive transport also enables colonization of new habitats at times when flight by adults is not an option. PMID:17148325

  2. Polyhydroxyalkanoates production by actinobacteria isolated from soil.

    PubMed

    Matias, Fernanda; Bonatto, Diego; Padilla, Gabriel; Rodrigues, Maria Filomena de Andrade; Henriques, João Antonio Pêgas

    2009-07-01

    Polyhydroxyalkanoates (PHAs) are biodegradable and renewable polymers produced by a wide range of bacterial groups. New microbial bioprospection approaches have become an important way to find new PHA producers and new synthesized polymers. Over the past years, bacteria belonging to actinomycetes group have become known as PHA producers, such as Nocardia and Rhodococcus species, Kineosphaera limosa Liu et al. 2002, and, more recently, Streptomyces species. In this paper, we disclose that there are more actinobacteria PHA producers in addition to the genera cited. Some unusual genera, such as Streptoalloteichus, and some genera frequently present in soil, such as Streptacidiphilus, have been found. Thirty-four isolates were able to accumulate poly(3-hydroxybutyrate) and a number of these have traces of poly(3-hydroxyvalerate) when cultivated on glucose or glucose and casein as carbon source. Furthermore, some strains showed traces of medium chain length PHA. Transmission electron microscopy demonstrated that the PHA accumulation occurs in hyphae and spores. PMID:19767851

  3. Downstream-migrating fluvial point bars in the rock record

    NASA Astrophysics Data System (ADS)

    Ghinassi, Massimiliano; Ielpi, Alessandro; Aldinucci, Mauro; Fustic, Milovan

    2016-04-01

    Classical models developed for ancient fluvial point bars are based on the assumption that meander bends invariably increase their radius as meander-bend apices migrate in a direction transverse to the channel-belt axis (i.e., meander bend expansion). However, many modern meandering rivers are also characterized by down-valley migration of the bend apex, a mechanism that takes place without a significant change in meander radius and wavelength. Downstream-migrating fluvial point bars (DMFPB) are the dominant architectural element of these types of meander belts. Yet they are poorly known from ancient fluvial-channel belts, since their disambiguation from expansional point bars often requires fully-3D perspectives. This study aims to review DMFPB deposits spanning in age from Devonian to Holocene, and to discuss their main architectural and sedimentological features from published outcrop, borehole and 3D-seismic datasets. Fluvial successions hosting DMFPB mainly accumulated in low accommodation conditions, where channel belts were affected by different degrees of morphological (e.g., valleys) or tectonic (e.g., axial drainage of shortening basins) confinement. In confined settings, bends migrate downstream along the erosion-resistant valley flanks and little or no floodplain deposits are preserved. Progressive floor aggradation (e.g., valley filling) allow meander belts with DMFPB to decrease their degree of confinement. In less confined settings, meander bends migrate downstream mainly after impinging against older, erosion-resistant channel fill mud. By contrast, tectonic confinement is commonly associated with uplifted alluvial plains that prevented meander-bend expansion, in turn triggering downstream translation. At the scale of individual point bars, translational morphodynamics promote the preservation of downstream-bar deposits, whereas the coarser-grained upstream and central beds are less frequently preserved. However, enhanced preservation of upstream-bar deposits can be controlled by aggradation at the scale of the entire meander belt. Despite their different preservation potential, the sedimentology of downstream-bar deposits is overall similar to that of expansional bars, since a downstream decrease in grain size and dominance of upbar-directed palaeoflows are observed in both cases. Bar-tail deposits are instead distinctive of DMFPB, specifically when channel-flow impinges at high angle against river outer banks. There, fine-grained counter-point bars or coarse-grained eddy-accretion deposits can accumulate. Channel belts dominated by DMFPB develop cross-sectional configurations featuring two main marginal trenches, commonly filled with bar tail deposits.

  4. Birds Generally Carry a Small Repertoire of Bitter Taste Receptor Genes.

    PubMed

    Wang, Kai; Zhao, Huabin

    2015-09-01

    As they belong to the most species-rich class of tetrapod vertebrates, birds have long been believed to possess an inferior taste system. However, the bitter taste is fundamental in birds to recognize dietary toxins (which are typically bitter) in potential food sources. To characterize the evolution of avian bitter taste receptor genes (Tas2rs) and to test whether dietary toxins have shaped the repertoire size of avian Tas2rs, we examined 48 genomes representing all but 3 avian orders. The total number of Tas2r genes was found to range from 1 in the domestic pigeon to 12 in the bar-tailed trogon, with an average of 4, which suggested that a much smaller Tas2r gene repertoire exists in birds than in other vertebrates. Furthermore, we uncovered a positive correlation between the number of putatively functional Tas2rs and the abundance of potential toxins in avian diets. Because plant products contain more toxins than animal tissues and insects release poisonous defensive secretions, we hypothesized that herbivorous and insectivorous birds may demand more functional Tas2rs than carnivorous birds feeding on noninsect animals. Our analyses appear to support this hypothesis and highlight the critical role of taste perception in birds. PMID:26342138

  5. Birds Generally Carry a Small Repertoire of Bitter Taste Receptor Genes

    PubMed Central

    Wang, Kai; Zhao, Huabin

    2015-01-01

    As they belong to the most species-rich class of tetrapod vertebrates, birds have long been believed to possess an inferior taste system. However, the bitter taste is fundamental in birds to recognize dietary toxins (which are typically bitter) in potential food sources. To characterize the evolution of avian bitter taste receptor genes (Tas2rs) and to test whether dietary toxins have shaped the repertoire size of avian Tas2rs, we examined 48 genomes representing all but 3 avian orders. The total number of Tas2r genes was found to range from 1 in the domestic pigeon to 12 in the bar-tailed trogon, with an average of 4, which suggested that a much smaller Tas2r gene repertoire exists in birds than in other vertebrates. Furthermore, we uncovered a positive correlation between the number of putatively functional Tas2rs and the abundance of potential toxins in avian diets. Because plant products contain more toxins than animal tissues and insects release poisonous defensive secretions, we hypothesized that herbivorous and insectivorous birds may demand more functional Tas2rs than carnivorous birds feeding on noninsect animals. Our analyses appear to support this hypothesis and highlight the critical role of taste perception in birds. PMID:26342138

  6. Diversity and ecological tolerance of bacteria isolated from the rhizosphere of halophyton plants living nearby Kiskunság soda ponds, Hungary.

    PubMed

    Borsodi, Andrea K; Bárány, Ágnes; Krett, Gergely; Márialigeti, Károly; Szili-Kovács, Tibor

    2015-06-01

    Many halophytes and halophilic microorganisms are capable to adapt to the extremities of saline habitats. This study reveals the taxonomic diversity and ecological tolerance of bacteria isolated from the rhizosphere of three different halophytes (Bolboschoenus maritimus, Puccinellia limosa and Aster tripolium) living in the vicinity of Kiskunság soda ponds. Following a sampling in September 2013, altogether 76 bacterial strains were isolated using two different media. The strains were identified on the basis of 16S rRNA gene sequencing following ARDRA grouping. Salt and pH tolerance of the strains were examined by measuring their growth in broths containing 0-15% NaCl (w/V) and characterized with pH 7-12 values. Among the strains genera of Anaerobacillus, Bacillus and Exiguobacterium (Firmicutes), Agromyces, Isoptericola, Microbacterium, Micrococcus, Nocardiopsis, Nesterenkonia and Streptomyces (Actinobacteria), Halomonas and Idiomarina (Proteobacteria) and Anditalea (Bacteroidetes) were identified. The Bolboschoenus and Puccinellia samples characterized with the highest pH and electric conductivity values were dominated by Bacillus, Halomonas and Nesterenkonia, respectively. The salt tolerance of the bacterial strains was strongly dependent on the sampling location and plant species. In contrast, growth of bacterial strains in broths with alkaline pH values was more balanced. The strains from the Puccinellia sample showed the widest salt and pH tolerance. PMID:26132838

  7. Isoprene emission from a subarctic peatland under enhanced UV-B radiation.

    PubMed

    Tiiva, Päivi; Rinnan, Riikka; Faubert, Patrick; Räsänen, Janne; Holopainen, Toini; Kyrö, Esko; Holopainen, Jarmo K

    2007-01-01

    Isoprene is a reactive hydrocarbon with an important role in atmospheric chemistry, and emissions from vegetation contribute to atmospheric carbon fluxes. The magnitude of isoprene emissions from arctic peatlands is not known, and it may be altered by increasing UV-B radiation. Isoprene emission was measured with the dynamic chamber method from a subarctic peatland under long-term enhancement of UV-B radiation targeted to correspond to a 20% loss in the stratospheric ozone layer. The site type of the peatland was a flark fen dominated by the moss Warnstorfia exannulata and sedges Eriophorum russeolum and Carex limosa. The relationship between species densities and the emission was also assessed. Isoprene emissions were significantly increased by enhanced UV-B radiation during the second (2004) and the fourth (2006) growing seasons under the UV-B exposure. Emissions were related to the density of E. russeolum. The dominant moss, W. exannulata, proved to emit small amounts of isoprene in a laboratory trial. Subarctic fens, even without Sphagnum moss, are a significant source of isoprene to the atmosphere, especially under periods of warm weather. Warming of the Arctic together with enhanced UV-B radiation may substantially increase the emissions. PMID:17888116

  8. Microcystin-producing and non-producing cyanobacterial blooms collected from the Central India harbor potentially pathogenic Vibrio cholerae.

    PubMed

    Chaturvedi, Prashant; Kumar Agrawal, Manish; Nath Bagchi, Suvendra

    2015-05-01

    On the basis of relative abundance, frequency and biovolume, the important value index ranks were assigned to individual cyanobacteria in phytoplankton samples collected from fourteen water resources of Central India. The mcyABDE genes were detected in all the blooms with Microcystis (-aeruginosa, -viridis, -panniformis, -botrys) as being the major constituent morphospecies. On the other hand, blooms composed of primarily Oscillatoria (-limosa,-agardhii, -laetevirens) along with Anabaena, Nostoc, Phormidium and Spirulina as sub-dominant forms exhibited quite a patchy distribution of one or the other mcy genes. Fifty percent of Microcystis- but none of the Oscillatoria dominant blooms produced microcystins-RR and desmethyl-RR at 0.03-0.41mgg(-1) bloom dry mass. Traces of dissolved microcystin was detected in lake water, which is well below the WHO guideline. Irrespective of cyanobacterial composition and microcystin production ability, during the study period 43-64% of the cyanobacterial bloom samples exhibited association of viable but nonculturable forms of Vibrio cholerae O1 and O139, as evident from amplification of the antigen genes. We believe that spread of endemic cholera is the major threat associated with harmful algal blooms. PMID:25682583

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

    PubMed

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

    2013-07-01

    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 β-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

  10. Goals and objectives: chapter 1

    USGS Publications Warehouse

    Bart, Jonathan; Johnston, Victoria

    2012-01-01

    We report results from shorebird surveys in the North American Arctic, defined here as Bird Conservation Regions 2 and 3 of the North American Bird Conservation Initiative (http://www.nabci.net/International/English/bcrmap.html). The surveys estimate population size and trend, and provide information on habitat relationships, at the regional and Arctic-wide scale (Table 1, Fig 1). Of the 53 species of shorebirds that breed in the United States and Canada, 26 (47%) breed in the arctic in sufficient numbers that arctic surveys are an important part of monitoring programs for them (Brown et al. 2001, Donaldson et al. 2000; Table 1). Arctic-breeding shorebirds are a diverse group that exhibits a wide range of migration, reproductive, and wintering strategies (Table 1.1). Some species migrate a short distance to the northern United States and southern Canada (e.g. Purple Sandpiper; for scientific names, see Appendix D), while others undertake epic migrations to West Africa (e.g. Red Phalarope) or southern South America (e.g. Hudsonian Godwit, Red Knot). Some migrate in huge flocks, while others trickle south singly or in small groups. There are monogamous, polygamous, and polyandrous breeders, and most habitats in the Arctic provide nesting opportunities for shorebird species. Despite their different life history characteristics, all Arctic shorebird species share two traits: 1) they are all are migrants (none inhabit the Arctic year-round) and 2) because of their migratory behavior, all are exposed to anthropogenic hazards at some point(s) in their life cycle.

  11. Avian assemblages on altered grasslands

    USGS Publications Warehouse

    Knopf, Fritz L.

    1994-01-01

    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.

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

    PubMed

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

    2012-09-01

    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

  13. Multidisciplinary approach to identify aquifer-peatland connectivity

    NASA Astrophysics Data System (ADS)

    Larocque, Marie; Pellerin, Stéphanie; Cloutier, Vincent; Ferlatte, Miryane; Munger, Julie; Quillet, Anne; Paniconi, Claudio

    2015-04-01

    In southern Quebec (Canada), wetlands sustain increasing pressures from agriculture, urban development, and peat exploitation. To protect both groundwater and ecosystems, it is important to be able to identify how, where, and to what extent shallow aquifers and wetlands are connected. This study focuses on peatlands which are especially abundant in Quebec. The objective of this research was to better understand aquifer-peatland connectivity and to identify easily measured indicators of this connectivity. Geomorphology, hydrogeochemistry, and vegetation were selected as key indicators of connectivity. Twelve peatland transects were instrumented and monitored in the Abitibi (slope peatlands associated with eskers) and Centre-du-Quebec (depression peatlands) regions of Quebec (Canada). Geomorphology, geology, water levels, water chemistry, and vegetation species were identified/measured on all transects. Flow conditions were simulated numerically on two typical transects. Results show that a majority of peatland transects receives groundwater from a shallow aquifer. In slope peatlands, groundwater flows through the organic deposits towards the peatland center. In depression peatlands, groundwater flows only 100-200 m within the peatland before being redirected through surface routes towards the outlet. Flow modeling and sensitivity analysis have identified that the thickness and hydraulic conductivity of permeable deposits close to the peatland and beneath the organic deposits influence flow directions within the peatland. Geochemical data have confirmed the usefulness of total dissolved solids (TDS) exceeding 14 mg/L as an indicator of the presence of groundwater within the peatland. Vegetation surveys have allowed the identification of species and groups of species that occur mostly when groundwater is present, for instance Carex limosa and Sphagnum russowii. Geomorphological conditions (slope or depression peatland), TDS, and vegetation can be measured/observed with limited effort in the field. Results from this study have the potential to help water managers and decision makers better understand and characterize aquifer-peatland interactions.

  14. Two New Species of Homalometron (Digenea: Apocreadiidae) from Nearctic Freshwater Fundulids, Elucidation of the Life Cycle of H. cupuloris, and Molecular Phylogenetic Analysis of Some Congeners.

    PubMed

    Fayton, Thomas J; Curran, Stephen S; Andres, Michael J; Overstreet, Robin M; McAllister, Chris T

    2016-02-01

    Two species of digeneans belonging in Homalometron are described from Nearctic freshwater fundulid fishes: Homalometron robisoni n. sp. is described from the Blackstripe Topminnow, Fundulus notatus , from Oklahoma and Homalometron frocioneae n. sp. is described from the Banded Killifish, Fundulus diaphanus , from New York. Homalometron robisoni n. sp. differs from all congeners by having vitelline follicles that extend into the forebody, a feature that necessitates altering the generic diagnosis for the genus. Homalometron frocioneae n. sp. may be distinguished from North and Middle American congeners by the position of the intestinal bifurcation (relatively more posterior in the forebody than in other species) and tegumental spine coverage on the body (spines are absent from the posterior body extremity and on most of the dorsal surface). Comparison of ribosomal DNA (ITS 1 and 2 regions, 5.8S gene, and partial fragment of 28S gene) from the 2 new species and some congeners from the Western Hemisphere provided evidence for the validity of the 2 new species and affirmed a close relationship between H. robisoni n. sp. and Homalometron pallidum. Comparison of ribosomal DNA from newly collected Homalometron spp. and larval stages of an apocreadiid from brackish water hydrobiid snails (cercariae in rediae in Littoridinops palustris and metacercariae in L. palustris and Amnicola limosa ) from a tidal river in Mississippi revealed that larval stages represented Homalometron cupuloris. A phylogeny based on Bayesian inference analysis using partial 28S rDNA gene fragments from 14 species of Homalometron (all from the Western Hemisphere) and 1 megaperine and rooted by a second megaperine was conducted and produced a strongly supported phylogram that estimates the interrelationships among species. The estimated phylogeny suggests that ecological factors such as salinity and food web interactions between species of Homalometron, intermediate hosts, and fishes drive coevolutionary forces influencing speciation within Homalometron. PMID:26541490

  15. Generation, transport and preservation of armoured mudballs in an ephemeral gully system

    NASA Astrophysics Data System (ADS)

    Mather, Anne; Stokes, Martin; Pirrie, Duncan; Hartley, Richard

    2008-08-01

    Armoured mudballs have been reported from modern fluvial catchments and preserved in ancient (Quaternary and older) sedimentary sequences. Despite many descriptions of mudballs in the literature there is little systematic analysis of their physical properties, genesis, transport and deposition within alluvial sequences. This study uses two adjacent catchments developed on identical geology in southeast Spain that offer a unique opportunity to examine the key controls on armoured mudball development as one catchment produces armoured mudball whilst the second does not. Field survey using a Total Station together with laboratory tests for material composition and aggregate stability were used to examine the catchment and the armoured mudballs. The results show that the generation of the armoured mudballs is heavily dependent on the correct sediment supply (suitable aggregates to act as mudball 'seeds', and suitable fragments to source the armour) and good slope-channel coupling within the catchment. Coupling is facilitated by steep gully sides which deliver the weathered blocks of marl (mudball 'seeds') to the gully floor. The 'seeds' form the core of the mudballs in the 'mudball factory' zone. If the 'seeds' are subjected to sealing by moisture from rainfall the mudball will hold together through negative pore pressures and can be transported by the ensuing gully flow. As the mudball rolls it picks up a surface armour which becomes embedded into the mudball. With longer transport paths the turbulent nature of the flow creates spherical mudballs which are size sorted downstream by the hydraulics of the flow rather than attrition. Armoured mudball deposition occurs within unit braid bars in areas of waning flow (due to transmission losses), within vegetated, point or mid-channel bars. The armoured mudballs are preferentially deposited within the coarser bar head of these depositional units, with smaller marl fragments forming the finer bar tail. Trenching of the bars reveals that the armoured mudballs are preserved in the subsurface although they may become increasingly flattened upon burial at depth, and may be difficult to recognise due to disaggregation by roots. This study suggests that armoured mudballs recognised in ancient alluvial sequences imply seasonality of climate and good slope-channel coupling within the catchment area, and that they are capable of transporting delicate flora undamaged, making them good targets for pollen recovery in ancient alluvial sequences. Where armoured mudballs were present but go unrecognised in the ancient record the mode and energy of transportation and deposition of the fine sediment may be misinterpreted as the fines are in fact being transported as bedload rather than suspended load. The armoured mudballs have also been noted to transport pristine microfauna such as ostracod shells from the source area material. This may provide challenges to palaeoenvironmental interpretations of the mud-dominated unit as environmentally significant fauna may not be contemporaneous with the unit.

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    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.