The Experts below are selected from a list of 18603 Experts worldwide ranked by ideXlab platform
William K Milsom - One of the best experts on this subject based on the ideXlab platform.
-
altitude matters differences in cardiovascular and respiratory responses to hypoxia in bar headed Geese reared at high and low altitudes
The Journal of Experimental Biology, 2016Co-Authors: Sabine L Lague, Beverly Chua, Anthony P Farrell, Yuxiang Wang, William K MilsomAbstract:ABSTRACT Bar-headed Geese ( Anser indicus ) fly at high altitudes during their migration across the Himalayas and Tibetan plateau. However, we know relatively little about whether rearing at high altitude (i.e. phenotypic plasticity) facilitates this impressive feat because most of what is known about their physiology comes from studies performed at sea level. To provide this information, a comprehensive analysis of metabolic, cardiovascular and ventilatory responses to progressive decreases in the equivalent fractional composition of inspired oxygen ( F i O 2 : 0.21, 0.12, 0.09, 0.07 and 0.05) was made on bar-headed Geese reared at either high altitude (3200 m) or low altitude (0 m) and on barnacle Geese ( Branta leucopsis ), a low-altitude migrating species, reared at low altitude (0 m). Bar-headed Geese reared at high altitude exhibited lower metabolic rates and a modestly increased hypoxic ventilatory response compared with low-altitude-reared bar-headed Geese. Although the in vivo oxygen equilibrium curves and blood-oxygen carrying capacity did not differ between the two bar-headed goose study groups, the blood-oxygen carrying capacity was higher than that of barnacle Geese. Resting cardiac output also did not differ between groups and increased at least twofold during progressive hypoxia, initially as a result of increases in stroke volume. However, cardiac output increased at a higher F i O 2 threshold in bar-headed Geese raised at high altitude. Thus, bar-headed Geese reared at high altitude exhibited a reduced oxygen demand at rest and a modest but significant increase in oxygen uptake and delivery during progressive hypoxia compared with bar-headed Geese reared at low altitude.
-
maximum running speed of captive bar headed Geese is unaffected by severe hypoxia
PLOS ONE, 2014Co-Authors: Lucy A Hawkes, Graham R. Scott, William K Milsom, P J Butler, Peter B Frappell, Jessica U Meir, Charles M BishopAbstract:While bar-headed Geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these Geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed Geese and barnacle Geese (a low altitude species) during exercise in hypoxia. Bar-headed Geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min�1. Barnacle Geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min�1) was significantly lower than bar-headed Geese. In bar-headed Geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed Geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed Geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which Geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare.
-
Molecular evolution of cytochrome c oxidase underlies high-altitude adaptation in the bar-headed goose
Molecular Biology and Evolution, 2011Co-Authors: Graham R. Scott, Angela L M Scott, Patricia M Schulte, Jeffrey G Richards, Stuart Egginton, William K MilsomAbstract:Bar-headed Geese (Anser indicus) fly at up to 9,000 m elevation during their migration over the Himalayas, sustaining high metabolic rates in the severe hypoxia at these altitudes. We investigated the evolution of cardiac energy metabolism and O(2) transport in this species to better understand the molecular and physiological mechanisms of high-altitude adaptation. Compared with low-altitude Geese (pink-footed Geese and barnacle Geese), bar-headed Geese had larger lungs and higher capillary densities in the left ventricle of the heart, both of which should improve O(2) diffusion during hypoxia. Although myoglobin abundance and the activities of many metabolic enzymes (carnitine palmitoyltransferase, citrate synthase, 3-hydroxyacyl-coA dehydrogenase, lactate dehydrogenase, and pyruvate kinase) showed only minor variation between species, bar-headed Geese had a striking alteration in the kinetics of cytochrome c oxidase (COX), the heteromeric enzyme that catalyzes O(2) reduction in oxidative phosphorylation. This was reflected by a lower maximum catalytic activity and a higher affinity for reduced cytochrome c. There were small differences between species in messenger RNA and protein expression of COX subunits 3 and 4, but these were inconsistent with the divergence in enzyme kinetics. However, the COX3 gene of bar-headed Geese contained a nonsynonymous substitution at a site that is otherwise conserved across vertebrates and resulted in a major functional change of amino acid class (Trp-116 → Arg). This mutation was predicted by structural modeling to alter the interaction between COX3 and COX1. Adaptations in mitochondrial enzyme kinetics and O(2) transport capacity may therefore contribute to the exceptional ability of bar-headed Geese to fly high.
-
evolution of muscle phenotype for extreme high altitude flight in the bar headed goose
Proceedings of The Royal Society B: Biological Sciences, 2009Co-Authors: Graham R. Scott, Jeffrey G Richards, Stuart Egginton, William K MilsomAbstract:Bar-headed Geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed Geese with that of low altitude birds (barnacle Geese, pink-footed Geese, greylag Geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed Geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O2 diffusion capacity from the blood and reduce intracellular O2 diffusion distances, respectively. The unique differences in bar-headed Geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O2 kinetics and phosphorylation efficiencies across species. Bar-headed Geese have therefore evolved for exercise in hypoxia by enhancing the O2 supply to flight muscle.
P J Butler - One of the best experts on this subject based on the ideXlab platform.
-
maximum running speed of captive bar headed Geese is unaffected by severe hypoxia
PLOS ONE, 2014Co-Authors: Lucy A Hawkes, Graham R. Scott, William K Milsom, P J Butler, Peter B Frappell, Jessica U Meir, Charles M BishopAbstract:While bar-headed Geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these Geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed Geese and barnacle Geese (a low altitude species) during exercise in hypoxia. Bar-headed Geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min�1. Barnacle Geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min�1) was significantly lower than bar-headed Geese. In bar-headed Geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed Geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed Geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which Geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare.
-
the paradox of extreme high altitude migration in bar headed Geese anser indicus
Proceedings of The Royal Society B: Biological Sciences, 2013Co-Authors: Lucy A Hawkes, Yuansheng Hou, Sivananinthaperumal Balachandran, Nyambayar Batbayar, P J Butler, Beverly Chua, David C Douglas, Peter B Frappell, Scott H NewmanAbstract:Bar-headed Geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why Geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed Geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 Geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound Geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed Geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima.
-
predicting the rate of oxygen consumption from heart rate in barnacle Geese branta leucopsis effects of captivity and annual changes in body condition
The Journal of Experimental Biology, 2009Co-Authors: Steven J Portugal, Peter B Frappell, Jonathan A Green, Phillip Cassey, P J ButlerAbstract:SUMMARY Quantifying a relationship between heart rate ( f H ) and rate of oxygen consumption ( V O 2 ) allows the estimation of V O 2 from f H recordings in free-ranging birds. It has been proposed that this relationship may vary throughout an animal9s annual cycle, due to changes in physiological status. Barnacle Geese, Branta leucopsis , provide an ideal model to test this hypothesis, as they exhibit significant intra-annual variability in body mass, body composition and abdominal temperature, even in captivity. Heart rate data loggers were implanted in 14 captive barnacle Geese, and at six points in the year the relationship between f H and V O 2 was determined. The f H / V O 2 relationship was also determined in seven moulting wild barnacle Geese to examine whether relationships from captive animals might be applicable to wild animals. In captive barnacle Geese, the f H / V O 2 relationship was significantly different only between two out of the six periods when the relationship was determined (late September–early October and November). Accounting for changes in physiological parameters such as body mass, body composition and abdominal temperature did not eliminate this difference. The relationship between f H and V O 2 obtained from wild Geese was significantly different from all of the relationships derived from the captive Geese, suggesting that it is not possible to apply calibrations from captive birds to wild Geese. However, the similarity of the f H and V O 2 relationship derived during moult in the captive Geese to those during the remainder of the annual cycle implies it is not unreasonable to assume that the relationship between f H / V O 2 during moult in the wild Geese is indicative of the relationship throughout the remainder of the annual cycle.
-
heart rate and the rate of oxygen consumption of flying and walking barnacle Geese branta leucopsis and bar headed Geese anser indicus
The Journal of Experimental Biology, 2002Co-Authors: S Ward, Charles M Bishop, A J Woakes, P J ButlerAbstract:We tested the hypotheses that the relationship between heart rate ( f H) and the rate of oxygen consumption ( V O2) differs between walking and flying in Geese and that f H and V O2 have a U-shaped relationship with flight speed. We trained barnacle Geese Branta leucopsis (mean mass 2.1 kg) and bar-headed Geese Anser indicus (mean mass 2.6 kg) to walk inside a respirometer on a treadmill and to fly in a wind tunnel with a respirometry mask at a range of speeds. We measured f H and V O2 simultaneously during walking on the treadmill in five individuals of each species and in one bar-headed goose and four barnacle Geese during flight in the wind tunnel. The relationships between f H and V O2 were significantly different between flying and walking. V O2 was higher, and the increment in V O2 for a given increase in f H was greater, for flying than for walking Geese. The relationship between f H and V O2 of free-living barnacle Geese during their natural migratory flights must differ from that measured in the wind tunnel, since the f H of wild migratory birds corresponds to values of V O2 that are unrealistically low when using the calibration relationship for our captive birds. Neither f H nor V O2 varied with flight velocity across the range of speeds over which the Geese would fly sustainably.
Graham R. Scott - One of the best experts on this subject based on the ideXlab platform.
-
maximum running speed of captive bar headed Geese is unaffected by severe hypoxia
PLOS ONE, 2014Co-Authors: Lucy A Hawkes, Graham R. Scott, William K Milsom, P J Butler, Peter B Frappell, Jessica U Meir, Charles M BishopAbstract:While bar-headed Geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these Geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed Geese and barnacle Geese (a low altitude species) during exercise in hypoxia. Bar-headed Geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min�1. Barnacle Geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min�1) was significantly lower than bar-headed Geese. In bar-headed Geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed Geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed Geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which Geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare.
-
Molecular evolution of cytochrome c oxidase underlies high-altitude adaptation in the bar-headed goose
Molecular Biology and Evolution, 2011Co-Authors: Graham R. Scott, Angela L M Scott, Patricia M Schulte, Jeffrey G Richards, Stuart Egginton, William K MilsomAbstract:Bar-headed Geese (Anser indicus) fly at up to 9,000 m elevation during their migration over the Himalayas, sustaining high metabolic rates in the severe hypoxia at these altitudes. We investigated the evolution of cardiac energy metabolism and O(2) transport in this species to better understand the molecular and physiological mechanisms of high-altitude adaptation. Compared with low-altitude Geese (pink-footed Geese and barnacle Geese), bar-headed Geese had larger lungs and higher capillary densities in the left ventricle of the heart, both of which should improve O(2) diffusion during hypoxia. Although myoglobin abundance and the activities of many metabolic enzymes (carnitine palmitoyltransferase, citrate synthase, 3-hydroxyacyl-coA dehydrogenase, lactate dehydrogenase, and pyruvate kinase) showed only minor variation between species, bar-headed Geese had a striking alteration in the kinetics of cytochrome c oxidase (COX), the heteromeric enzyme that catalyzes O(2) reduction in oxidative phosphorylation. This was reflected by a lower maximum catalytic activity and a higher affinity for reduced cytochrome c. There were small differences between species in messenger RNA and protein expression of COX subunits 3 and 4, but these were inconsistent with the divergence in enzyme kinetics. However, the COX3 gene of bar-headed Geese contained a nonsynonymous substitution at a site that is otherwise conserved across vertebrates and resulted in a major functional change of amino acid class (Trp-116 → Arg). This mutation was predicted by structural modeling to alter the interaction between COX3 and COX1. Adaptations in mitochondrial enzyme kinetics and O(2) transport capacity may therefore contribute to the exceptional ability of bar-headed Geese to fly high.
-
evolution of muscle phenotype for extreme high altitude flight in the bar headed goose
Proceedings of The Royal Society B: Biological Sciences, 2009Co-Authors: Graham R. Scott, Jeffrey G Richards, Stuart Egginton, William K MilsomAbstract:Bar-headed Geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed Geese with that of low altitude birds (barnacle Geese, pink-footed Geese, greylag Geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed Geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O2 diffusion capacity from the blood and reduce intracellular O2 diffusion distances, respectively. The unique differences in bar-headed Geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O2 kinetics and phosphorylation efficiencies across species. Bar-headed Geese have therefore evolved for exercise in hypoxia by enhancing the O2 supply to flight muscle.
Charles M Bishop - One of the best experts on this subject based on the ideXlab platform.
-
maximum running speed of captive bar headed Geese is unaffected by severe hypoxia
PLOS ONE, 2014Co-Authors: Lucy A Hawkes, Graham R. Scott, William K Milsom, P J Butler, Peter B Frappell, Jessica U Meir, Charles M BishopAbstract:While bar-headed Geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these Geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed Geese and barnacle Geese (a low altitude species) during exercise in hypoxia. Bar-headed Geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min�1. Barnacle Geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min�1) was significantly lower than bar-headed Geese. In bar-headed Geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed Geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed Geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which Geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare.
-
heart rate and the rate of oxygen consumption of flying and walking barnacle Geese branta leucopsis and bar headed Geese anser indicus
The Journal of Experimental Biology, 2002Co-Authors: S Ward, Charles M Bishop, A J Woakes, P J ButlerAbstract:We tested the hypotheses that the relationship between heart rate ( f H) and the rate of oxygen consumption ( V O2) differs between walking and flying in Geese and that f H and V O2 have a U-shaped relationship with flight speed. We trained barnacle Geese Branta leucopsis (mean mass 2.1 kg) and bar-headed Geese Anser indicus (mean mass 2.6 kg) to walk inside a respirometer on a treadmill and to fly in a wind tunnel with a respirometry mask at a range of speeds. We measured f H and V O2 simultaneously during walking on the treadmill in five individuals of each species and in one bar-headed goose and four barnacle Geese during flight in the wind tunnel. The relationships between f H and V O2 were significantly different between flying and walking. V O2 was higher, and the increment in V O2 for a given increase in f H was greater, for flying than for walking Geese. The relationship between f H and V O2 of free-living barnacle Geese during their natural migratory flights must differ from that measured in the wind tunnel, since the f H of wild migratory birds corresponds to values of V O2 that are unrealistically low when using the calibration relationship for our captive birds. Neither f H nor V O2 varied with flight velocity across the range of speeds over which the Geese would fly sustainably.
Anthony D Fox - One of the best experts on this subject based on the ideXlab platform.
-
does snowmelt constrain spring migration progression in sympatric wintering arctic nesting Geese results from a far east asia telemetry study
Ibis, 2020Co-Authors: Xin Wang, Lei Cao, Lei Fang, Anthony D FoxAbstract:Telemetry data from sympatric Eastern Tundra Bean Geese Anser serrirostris captured on their winter quarters in the Yangtze River Floodplain, China, tracked to two discrete breeding areas (the Anadyr Region (AR) at 65°N and Central Russian Arctic (CRA) at 75°N) showed that, despite longer migration distance (6300 vs. 5300 km), AR Geese reached their destination 23 days earlier than CRA Geese as a result of increasingly delayed date of 50% snow cover along the route of CRA Geese (based on satellite imagery data). Both groups arrived at breeding areas 8–9 days prior to the local date of 50% snow cover thaw, suggesting optimal timing of arrival for subsequent reproduction. Despite small sample sizes from one season of tracking, these intra‐specific data are the first to suggest that, in time‐limited Arctic‐nesting Geese, snowmelt conditions regulated the individual progress and duration of spring migration along the flyway to coincide with arrival at optimal spring conditions on breeding areas.
-
population estimates and geographical distributions of swans and Geese in east asia based on counts during the non breeding season
Bird Conservation International, 2016Co-Authors: Qiang Jia, Lei Cao, Kazuo Koyama, Changyong Choi, Hwajung Kim, Dali Gao, Guanhua Liu, Anthony D FoxAbstract:For the first time, we estimated the population sizes of two swan species and four goose species from observations during the non-breeding period in East Asia. Based on combined counts from South Korea, Japan and China, we estimated the total abundance of these species as follows: 42,000–47,000 Whooper Swans Cygnus cygnus ; 99,000–141,000 Tundra Swans C. columbianus bewickii ; 56,000–98,000 Swan Geese Anser cygnoides ; 157,000–194,000 Bean Geese A. fabalis ; 231,000–283,000 Greater White-fronted Geese A. albifrons ; and 14,000–19,000 Lesser White-fronted Geese A. erythropus. While the count data from Korea and Japan provide a good reflection of numbers present, there remain gaps in the coverage in China, which particularly affect the precision of the estimates for Bean, Greater and Lesser White-fronted Geese as well as Tundra Swans. Lack of subspecies distinction of Bean Geese in China until recently also limits our ability to determine the true status of A. f. middendorffii there, but all indications suggest this population numbers around 18,000 individuals and is in need of urgent attention. The small, highly concentrated and declining numbers of Lesser White-fronted Geese give concern for this species, as do the major declines in Greater White-fronted Geese in China (in contrast to numbers in Japan and Korea, considered to be a separate flyway). In the absence of any demographic data, it is impossible to interpret the causes of these changes in abundance. Improved monitoring, including demographic and tracking studies are required to provide the necessary information to retain populations in favourable conservation status.
-
Post-moult distribution and abundance of white-fronted Geese
2016Co-Authors: A. D. Fox, Anthony D Fox, Christian M. GlahderAbstract:Rapid increases in North American Canada Geese (Branta canadensis) summer-ing in West Greenland since the mid-1980s compare with declines in the endemic population of white-fronted Geese (Anser albifrons flavirostris) nesting in the same region since 1999 (wintering in Europe). To provide information on the distribution and abundance of the two species in Greenland during the prelude to the autumn migration back to winter quarters, we here report on the first ever post-moult aerial surveys of West Greenland between 64 ° and 73°N (from regular transects and transit reconnaissance flights in August 2007), which located 1888 Greenland white-fronted Geese and 6071 Canada Geese. Strip transect surveys found 733 Greenland white-fronted Geese and 1318 Canada Geese in the 993 km2 surveyed, which, given a white-fronted goose global population of 23 200 in winter 2007/08, suggests more than 41 500 Canada Geese in West Greenland post-moult in 2007. Virtually no Geese were found south of 66°N. The Eqalummiut nunaat–Nassuttuup nuna
-
food constraints explain the restricted distribution of wintering lesser white fronted Geese anser erythropus in china
Ibis, 2013Co-Authors: Xin Wang, Peihao Cong, Anthony D Fox, Lei CaoAbstract:More than 90% of the Lesser White-fronted Geese Anser erythropus in the Eastern Palearctic flyway population winter at East Dongting Lake, China. To explain this restricted distribution and to understand better the winter feeding ecology and habitat requirements of this poorly known species, we assessed their food availability, diet and energy budgets at this site through two winters. Lesser White-fronted Geese maintained a positive energy budget when feeding on above-ground green production of Eleocharis and Alopecurus in recessional grasslands in autumn and spring to accumulate fat stores. Such food was severely depleted by late November and showed no growth in mid-winter. Geese fed on more extensive old-growth Carex sedge meadows in mid-winter where they were in energy deficit and depleted endogenous fat stores. Geese failed to accumulate autumn fat stores in one year when high water levels prevented the Geese from using recessional grassland feeding areas. Fat stores remained lower throughout that winter and Geese left for breeding areas later in spring than in the previous year, perhaps reflecting the need to gain threshold fat stores for migration. Sedge meadows are widespread at other Yangtze River floodplain wetlands, but recessional grasslands are rare and perhaps restricted to parts of East Dongting Lake, which would explain the highly localized distribution of Lesser White-fronted Geese in China and their heavy use of these habitats at this site. Sympathetic management of water tables is essential to maintain the recessional grasslands in the best condition for Geese. Regular depletion of fat stores whilst grazing sedge meadows in mid-winter also underlines the need to protect the species from unnecessary anthropogenic disturbances that enhance energy expenditure. The specialized diet of the Lesser White-fronted Goose may explain its highly restricted winter distribution and global rarity.
-
within winter shifts in lesser white fronted goose anser erythropus distribution at east dongting lake china
Ardea, 2012Co-Authors: Peihao Cong, Xin Wang, Lei Cao, Anthony D FoxAbstract:At the important wintering site, East Dongting Lake in the Yangtze River floodplain, Lesser White-fronted Geese Anser erythropus showed within-season shifts in distribution and abundance between local areas. On arrival in November, over 4,000 Geese grazed high-biomass stands of new growth spikerush Eleocharis migoana on exposed mud flats at Caisang Lake. High feeding densities depleted Eleocharis by early December, when the Geese departed to feed on old-growth above-ground Carex heterolepis at nearby lakes. Cool, arid conditions inhibited plant growth until January, when the grass Alopecurus aequalis and C. heterolepis restarted growing, attracting Geese back to Caisang Lake. Greater numbers returned in late February when E. migoana began to grow, rapidly building to peak at 4,500 in late March when Geese began spring migration. Habitat management that maintains these patterns of plant growth and availability may be critical to keeping present Lesser White-fronted Goose numbers at this site.
