The Experts below are selected from a list of 4944 Experts worldwide ranked by ideXlab platform
Jesper Madsen - One of the best experts on this subject based on the ideXlab platform.
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seroprevalence of avian influenza in baltic common eiders somateria mollissima and pink footed geese anser brachyrhynchus
Environment International, 2020Co-Authors: Thomas Kjaer Christensen, Jesper Madsen, Su Shiung Lam, Rune Skjold Tjornlov, Ole Roland Therkildsen, Tobias Daugaardpetersen, Jose Maria Castano Ortiz, Wanxi Peng, Mael CharbonneauxAbstract:Abstract Blood plasma was collected during 2016–2018 from healthy incubating eiders (Somateria molissima, n = 183) in three Danish colonies, and healthy migrating pink-footed geese (Anser brachyrhynchus, n = 427) at their spring roost in Central Norway (Svalbard breeding population) and their novel Flyway through the Finnish Baltic Sea (Russian breeding population). These species and Flyways altogether represent terrestrial, brackish and marine ecosystems spanning from the Western to the Eastern and Northern part of the Baltic Sea. Plasma of these species was analysed for seroprevalence of specific avian influenza A (AI) antibodies to obtain information on circulating AI serotypes and exposure. Overall, antibody prevalence was 55% for the eiders and 47% for the pink-footed geese. Of AI-antibody seropositive birds, 12% (22/183) of the eiders and 3% (12/427) of the pink-footed geese had been exposed to AI of the potentially zoonotic serotypes H5 and/or H7 virus. AI seropositive samples selected at random (n = 33) showed a low frequency of serotypes H1, H6 and H9. Future projects should aim at sampling and isolating AI virus to characterize dominant serotypes and virus strains (PCR). This will increase our understanding of how AI exposure may affect health, breeding and population viability of Baltic common eiders and pink-footed geese as well as the potential spill-over to humans (zoonotic potential).
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connectivity between Flyway populations of waterbirds assessment of rates of exchange their causes and consequences
Journal of Applied Ecology, 2014Co-Authors: Jesper Madsen, Rune Skjold Tjornlov, Morten Frederiksen, Carl Mitchell, Arnor þ SigfussonAbstract:Summary 1. Conservation and management of migratory waterbirds use Flyway populations as the basic unit, and knowledge of the delineation, rate of exchange and gene flow between populations is fundamental. However, for the majority of global Flyway populations, information is too fragmentary to address connectivity between populations and, hence, insufficient to inform management. 2. We investigated the demographic connectivity between the eastern (breeding in Svalbard and wintering in Denmark, the Netherlands and Belgium) and western (breeding in Greenland or Iceland and wintering in Britain) Flyway populations of pink-footed geese Anser brachyrhynchus based on resightings of marked geese from both populations. Previous genetic analyses suggested a modest gene flow between the two populations. 3. Capture–recapture analysis conservatively estimated that mean annual movement probabilities were low (eastern to western population: 0071%, 95% CI = 0033–015%; western to eastern: 0076%, 95% CI = 0031–018%). Movement probability from eastern to western Flyway populations increased in years with high snow cover in the southernmost winter range in Belgium. Life histories of exchanged individuals from eastern to western (32 different individuals during 1988–2010) revealed that the majority entered Britain via Belgium and the Netherlands during winter; some returned to the eastern population via Belgium and/or the Netherlands, others moved northwards in Britain during the spring and appear to have migrated directly from Britain (western population) to Norway (eastern population). None of the birds from the eastern population emigrated permanently, but some individuals turned up in Britain in consecutive years. Out of nine individuals switching from western to eastern Flyway populations, three returned to Britain; the others were not subsequently resighted. An alternative winter strategy and spring Flyway over Britain to Norway is suggested, used by hundreds to thousands of eastern birds, particularly following severe winters. Thus, the two populations currently appear to be demographically closed; low genetic connectivity probably reflects dispersal over longer time. 4. Synthesis and applications. Current initiatives to internationally manage the eastern population of pink-footed geese do not need to consider net immigration in predictive harvest models. For waterbirds in general, a targeted approach to evaluate connectivity, using classic marking studies in combination with molecular methods and focussed sampling on breeding grounds, is recommended to better underpin management decisions at population levels.
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optimal management of a goose Flyway migrant management at minimum cost
Journal of Applied Ecology, 2008Co-Authors: Marcel Klaassen, Silke Bauer, Jesper Madsen, Hugh P PossinghamAbstract:We adopt a 'whole Flyway' approach to modelling scenarios for protecting migratory birds, aiming at efficient and cost-effective conservation of Flyway habitat. We developed a model to minimize Flyway management costs while safeguarding a migrating bird population. The model assumes that the intensity of the birds' use of sites can be manipulated by varying management regimes (with concomitant costs) and that the birds make optimal use of the conditions created along their Flyway. We used dynamic programming to find the sequence of migratory decisions that maximizes the fitness of the migrants given a range of management scenarios, followed by a management cost estimate of all these scenarios and selection of those scenarios yielding an optimal solution from both an economic and the migrants' perspective. Using the population of pink-footed geese Anser brachyrhynchus that breed in Svalbard as an example, we calculated that the cheapest management scenario given current compensation payment rates at the various goose stopover sites yielded a 35% cost saving over current management. This cheapest scenario provides a migration itinerary that is very similar to the current itinerary used by the geese. This is fortuitous since changing environmental conditions may put the migrants at risk. Synthesis and application. Given the global threats to migratory birds, developing a framework for efficient and effective conservation of Flyway habitat is an urgent need. Such a framework may likewise be used to assist in controlling migrants causing conflict with agriculture, such as several goose species, in an economic and responsible fashion. Our suggested exemplified framework identified large unexplainable differences in management costs between regions. Differences in management costs between staging sites for birds make big differences to the optimal management of a Flyway. Hence, to achieve efficient and effective management of migratory birds, we firstly need an objective assessment of the cost of management in different locations, followed by a modelling approach as here advocated, and followed up by a collaborative action of managers along the entire Flyway.
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modelling behavioural and fitness consequences of disturbance for geese along their spring Flyway
Journal of Applied Ecology, 2005Co-Authors: Marcel Klaassen, Silke Bauer, Jesper Madsen, Ingunn TombreAbstract:For migratory birds the implications of environmental change may be difficult to predict because they use multiple sites during their annual cycle. Moreover, the migrants' use of these sites may be interdependent. Along the Flyway of the Svalbard pink-footed goose Anser brachyrhynchus population, Norwegian farmers use organized scaring to minimize goose use of their grasslands in spring. We assessed the consequences of this practice for regional site use of pink-footed geese along their spring migration route. 2. We used dynamic programming to find the sequence of migratory decisions that maximizes the fitness of female geese during spring migration, assuming scaring impinges on both food-intake rates and predation risk. The parameterization of the model was based on data gathered from individually marked pink-footed geese between 1991 and 2003. 3. The effect of scaring in terms of fitness and site use was most noticeable regarding food-intake rate. Scaring resulted in a redistribution of geese along the Flyway. Furthermore, the outcomes of the modelling exercises were highly dependent on whether or not the geese were omniscient or naive: at moderate scaring levels naive geese were predicted to succumb. 4. On a qualitative basis there was good correspondence between the predictions from the model and the empirical evidence gathered to date. 5. Synthesis and applications. Besides highlighting the importance of learning and changing behaviour in an adaptive fashion, our modelling exercise indicated the potential vulnerability of the geese to abrupt environmental change. In addition, the exercise emphasized the interdependence of site use along the migratory Flyway. The model supports the necessity for an integrated Flyway management approach. In Norway, discussion is ongoing about the future management of the spring conflict between [KEYWORDS: Anser brachyrhynchus ; dynamic programming ; environmental change ; Flyway ; management ; pink-footed goose ; migration ; scaring]
Su Shiung Lam - One of the best experts on this subject based on the ideXlab platform.
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seroprevalence of avian influenza in baltic common eiders somateria mollissima and pink footed geese anser brachyrhynchus
Environment International, 2020Co-Authors: Thomas Kjaer Christensen, Jesper Madsen, Su Shiung Lam, Rune Skjold Tjornlov, Ole Roland Therkildsen, Tobias Daugaardpetersen, Jose Maria Castano Ortiz, Wanxi Peng, Mael CharbonneauxAbstract:Abstract Blood plasma was collected during 2016–2018 from healthy incubating eiders (Somateria molissima, n = 183) in three Danish colonies, and healthy migrating pink-footed geese (Anser brachyrhynchus, n = 427) at their spring roost in Central Norway (Svalbard breeding population) and their novel Flyway through the Finnish Baltic Sea (Russian breeding population). These species and Flyways altogether represent terrestrial, brackish and marine ecosystems spanning from the Western to the Eastern and Northern part of the Baltic Sea. Plasma of these species was analysed for seroprevalence of specific avian influenza A (AI) antibodies to obtain information on circulating AI serotypes and exposure. Overall, antibody prevalence was 55% for the eiders and 47% for the pink-footed geese. Of AI-antibody seropositive birds, 12% (22/183) of the eiders and 3% (12/427) of the pink-footed geese had been exposed to AI of the potentially zoonotic serotypes H5 and/or H7 virus. AI seropositive samples selected at random (n = 33) showed a low frequency of serotypes H1, H6 and H9. Future projects should aim at sampling and isolating AI virus to characterize dominant serotypes and virus strains (PCR). This will increase our understanding of how AI exposure may affect health, breeding and population viability of Baltic common eiders and pink-footed geese as well as the potential spill-over to humans (zoonotic potential).
Todd E Dawson - One of the best experts on this subject based on the ideXlab platform.
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using oxygen and hydrogen stable isotopes to track the migratory movement of sharp shinned hawks accipiter striatus along western Flyways of north america
PLOS ONE, 2020Co-Authors: Elizabeth A Wommack, Lisa Marrack, Stefania Mambelli, Joshua M Hull, Todd E DawsonAbstract:The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two Flyways from the measured isotope values of migrant's feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins than those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.
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using oxygen and hydrogen stable isotopes to track the migratory movement of sharp shinned hawks accipiter striatus along western Flyways of north america
bioRxiv, 2020Co-Authors: Elizabeth A Wommack, Lisa Marrack, Stefania Mambelli, Joshua M Hull, Todd E DawsonAbstract:Abstract The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two Flyways from the measured isotope values of migrant’s feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins then those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.
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stable isotope composition of feathers help track the migratory patterns of sharp shinned hawks accipiter striatus along western Flyways of north america
bioRxiv, 2019Co-Authors: Elizabeth A Wommack, Lisa Marrack, Stefania Mambelli, Joshua M Hull, Todd E DawsonAbstract:Abstract The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from different natal/breeding populations. We applied Stable Isotope Analysis (SIA) of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (IsoScapes) to formulate spatially explicit predictions of the origin of the migrant birds. For both hydrogen and oxygen isotope composition, novel relationships were assessed between the measured isotope values of feathers from A. striatus museum specimens of known origin and the IsoScape modeled compositions of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two Flyways from the measured isotope values of migrant’s feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The A. striatus from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen SIA to track the movement of birds of prey on continental scales.
Mael Charbonneaux - One of the best experts on this subject based on the ideXlab platform.
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seroprevalence of avian influenza in baltic common eiders somateria mollissima and pink footed geese anser brachyrhynchus
Environment International, 2020Co-Authors: Thomas Kjaer Christensen, Jesper Madsen, Su Shiung Lam, Rune Skjold Tjornlov, Ole Roland Therkildsen, Tobias Daugaardpetersen, Jose Maria Castano Ortiz, Wanxi Peng, Mael CharbonneauxAbstract:Abstract Blood plasma was collected during 2016–2018 from healthy incubating eiders (Somateria molissima, n = 183) in three Danish colonies, and healthy migrating pink-footed geese (Anser brachyrhynchus, n = 427) at their spring roost in Central Norway (Svalbard breeding population) and their novel Flyway through the Finnish Baltic Sea (Russian breeding population). These species and Flyways altogether represent terrestrial, brackish and marine ecosystems spanning from the Western to the Eastern and Northern part of the Baltic Sea. Plasma of these species was analysed for seroprevalence of specific avian influenza A (AI) antibodies to obtain information on circulating AI serotypes and exposure. Overall, antibody prevalence was 55% for the eiders and 47% for the pink-footed geese. Of AI-antibody seropositive birds, 12% (22/183) of the eiders and 3% (12/427) of the pink-footed geese had been exposed to AI of the potentially zoonotic serotypes H5 and/or H7 virus. AI seropositive samples selected at random (n = 33) showed a low frequency of serotypes H1, H6 and H9. Future projects should aim at sampling and isolating AI virus to characterize dominant serotypes and virus strains (PCR). This will increase our understanding of how AI exposure may affect health, breeding and population viability of Baltic common eiders and pink-footed geese as well as the potential spill-over to humans (zoonotic potential).
Elizabeth A Wommack - One of the best experts on this subject based on the ideXlab platform.
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using oxygen and hydrogen stable isotopes to track the migratory movement of sharp shinned hawks accipiter striatus along western Flyways of north america
PLOS ONE, 2020Co-Authors: Elizabeth A Wommack, Lisa Marrack, Stefania Mambelli, Joshua M Hull, Todd E DawsonAbstract:The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two Flyways from the measured isotope values of migrant's feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins than those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.
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using oxygen and hydrogen stable isotopes to track the migratory movement of sharp shinned hawks accipiter striatus along western Flyways of north america
bioRxiv, 2020Co-Authors: Elizabeth A Wommack, Lisa Marrack, Stefania Mambelli, Joshua M Hull, Todd E DawsonAbstract:Abstract The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two Flyways from the measured isotope values of migrant’s feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins then those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.
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stable isotope composition of feathers help track the migratory patterns of sharp shinned hawks accipiter striatus along western Flyways of north america
bioRxiv, 2019Co-Authors: Elizabeth A Wommack, Lisa Marrack, Stefania Mambelli, Joshua M Hull, Todd E DawsonAbstract:Abstract The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from different natal/breeding populations. We applied Stable Isotope Analysis (SIA) of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (IsoScapes) to formulate spatially explicit predictions of the origin of the migrant birds. For both hydrogen and oxygen isotope composition, novel relationships were assessed between the measured isotope values of feathers from A. striatus museum specimens of known origin and the IsoScape modeled compositions of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two Flyways from the measured isotope values of migrant’s feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The A. striatus from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen SIA to track the movement of birds of prey on continental scales.