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Journal articles on the topic 'Migratory trends'
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1
Gershon, Diane. "Migratory trends." Nature 349, no. 6309 (1991): 546–48. http://dx.doi.org/10.1038/349546a0.
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Kramer, Gunnar R., David E. Andersen, David A. Buehler, et al. "Population trends inVermivorawarblers are linked to strong migratory connectivity." Proceedings of the National Academy of Sciences 115, no. 14 (2018): E3192—E3200. http://dx.doi.org/10.1073/pnas.1718985115.
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Migratory species can experience limiting factors at different locations and during different periods of their annual cycle. In migratory birds, these factors may even occur in different hemispheres. Therefore, identifying the distribution of populations throughout their annual cycle (i.e., migratory connectivity) can reveal the complex ecological and evolutionary relationships that link species and ecosystems across the globe and illuminate where and how limiting factors influence population trends. A growing body of literature continues to identify species that exhibit weak connectivity wherein individuals from distinct breeding areas co-occur during the nonbreeding period. A detailed account of a broadly distributed species exhibiting strong migratory connectivity in which nonbreeding isolation of populations is associated with differential population trends remains undescribed. Here, we present a range-wide assessment of the nonbreeding distribution and migratory connectivity of two broadly dispersed Nearctic-Neotropical migratory songbirds. We used geolocators to track the movements of 70Vermivorawarblers from sites spanning their breeding distribution in eastern North America and identified links between breeding populations and nonbreeding areas. Unlike blue-winged warblers (Vermivora cyanoptera), breeding populations of golden-winged warblers (Vermivora chrysoptera) exhibited strong migratory connectivity, which was associated with historical trends in breeding populations: stable for populations that winter in Central America and declining for those that winter in northern South America.
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Baganha, Maria I. "The Lusophone Migratory System: Patterns and Trends." International Migration 47, no. 3 (2009): 5–20. http://dx.doi.org/10.1111/j.1468-2435.2009.00522.x.
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Farmer, Christopher J., David J. T. Hussell, and David Mizrahi. "DETECTING POPULATION TRENDS IN MIGRATORY BIRDS OF PREY." Auk 124, no. 3 (2007): 1047. http://dx.doi.org/10.1642/0004-8038(2007)124[1047:dptimb]2.0.co;2.
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Alomenu, H. S. "Current trends in African Migratory Locust plague prevention." Outlook on Agriculture 14, no. 4 (1985): 165–73. http://dx.doi.org/10.1177/003072708501400402.
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From the dawn of civilisation, locusts have been one of the great agricultural plagues, stripping vast areas bare of vegetation as they relentlessly advance. Experience shows that the most effective control measure is to attack the pest at its breeding grounds in the Niger Delta area as soon as it shows signs of swarming. Unfortunately, the prolonged sahelian drought – which for some years has put a natural brake on breeding – has encouraged complacency about the risks of another resurgence when this comes to an end.
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Farmer, Christopher J., David J. T. Hussell, and David Mizrahi. "Detecting Population Trends in Migratory Birds of Prey." Auk 124, no. 3 (2007): 1047–62. http://dx.doi.org/10.1093/auk/124.3.1047.
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Abstract Counts of visible migrants at traditional watchsites throughout North America provide an opportunity to augment population-monitoring efforts for birds of prey. We analyzed hourly counts of migrating raptors at one inland (Hawk Mountain Sanctuary, Pennsylvania) and one coastal (Cape May Point, New Jersey) watchsite in northeastern North America. Hourly counts of migrants have been collected for 38 years at Hawk Mountain Sanctuary and for 28 years at Cape May Point. We compared effort-adjusted, arithmetic-mean passage rates to five geometric-mean indexes for 12 species. We used reparameterized polynomial regression to estimate trends in the indexes and to test the significance of trends from 1976–1978 (average index over three-year period) to 2001–2003. Effort-adjusted, arithmetic-mean indexes corresponded to more sophisticated indexes on the complete data sets but did not perform well on simulated data with missing observation days. We recommend the use of a regression-based, date-adjusted index for the analysis of hawk-count data. This index produced trends similar to other geometric-mean indexes, performed well on data sets simulating reduced sampling frequency, and outperformed other indexes on data sets with large blocks of missing observation days. Correspondence between trends at the watchsites and trends from Breeding Bird Surveys (BBSs) suggests that migration counts provide robust estimates of population trends for raptors. Furthermore, migration counts allow the monitoring of species not detected by BBS and produce trends with greater precision for species sampled by both methods. Analysis of migration counts with appropriate methods holds considerable promise for contributing to the development of integrated strategies to monitor raptor populations. Detección de Tendencias Poblacionales en Aves de Presa Migratorias
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Feld, Serge. "Labor Force Trends and Immigration in Europe." International Migration Review 39, no. 3 (2005): 637–62. http://dx.doi.org/10.1111/j.1747-7379.2005.tb00283.x.
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Labor force trends up to 2025 for the fifteen countries (before May 1, 2004) of the European Community are examined. Will demographic decline have an early effect on manpower volume? An estimation is made to determine whether present migratory flow levels in these countries will be sufficient to counter labor force stagnation. Manpower trend scenarios are proposed for each country. They show highly contrasting situations. These countries favor different policies for mobilizing and increasing their manpower volume. There is wide divergence between the various EU countries as concerns their demographic situation and labor force participation rate as well as their social security systems. Considering these highly diverse national characteristics, the difficulty in arriving at a consensus on EU migratory policy harmonization is stressed.
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Lilleyman, Amanda, Danny I. Rogers, Micha V. Jackson, Richard A. Fuller, Gavin O'Brien, and Stephen T. Garnett. "An artificial site provides valuable additional habitat to migratory shorebirds in a tropical harbour." Pacific Conservation Biology 26, no. 3 (2020): 249. http://dx.doi.org/10.1071/pc19036.
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Migratory shorebirds are declining in all transequatorial flyways, most rapidly in the East Asian–Australasian Flyway. Population trends for shorebirds have been derived at a flyway and continental scale, but changes at the local scale are less well understood. Here we compare trends in migratory shorebird populations using natural and artificial roost sites within a tropical harbour, examine possible drivers of change, and identify appropriate conservation management responses. Counts of 19 migratory shorebird species from 2010 and 2018 showed that total abundance increased at an average annual rate of 3.3% (95% CI=1.3–5.4%, P=0.001) across five natural roost sites. This was driven largely by increases in great knot, with most other species declining. At an artificial site in an adjacent shorebird area, total abundance increased at an average annual rate of 14.5% (95% CI=10.5–18.6%, P ≤ 0.000), with few species declining. These results suggest that there is a need to include both natural and artificial sites within shorebird conservation and management planning and that trends in different species can be driven by a combination of local and external drivers.
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Bonilla, Frank, and Juan E. Hernandez Cruz. "Corrientes migratorias en Puerto Rico/Migratory Trends in Puerto Rico." Hispanic American Historical Review 76, no. 2 (1996): 333. http://dx.doi.org/10.2307/2517157.
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Bonilla, Frank. "Corrientes migratorias en Puerto Rico/Migratory Trends in Puerto Rico." Hispanic American Historical Review 76, no. 2 (1996): 333–34. http://dx.doi.org/10.1215/00182168-76.2.333.
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Blancher, Peter J., R. Dean Phoenix, Debra S. Badzinski, et al. "Population trend status of Ontario’s forest birds." Forestry Chronicle 85, no. 2 (2009): 184–201. http://dx.doi.org/10.5558/tfc85184-2.
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Recent population trends of Ontario’s forest birds were assessed by integrating results across 8 bird surveys to provide an estimate of trend status for all of Ontario, and for 2 forested regions of Ontario separately. Surveys with mid- and longterm trends were relied on most extensively in this assessment. Comparison of the first and second Breeding Bird Atlases was especially important for estimating trends in northern forests, but overall reliability of status assessments in the north was considered poor due to limited coverage and significant potential for bias. Trends of most forest birds were stable or positive at the Ontario-wide scale, with trends at least as positive as forest birds elsewhere in North America, and showing more positive trends overall than birds of agricultural landscapes. Nevertheless, individual species trends ranged from large declines to large increases, and several forest birds have been added to Species at Risk lists largely because of population declines. There were few differences in trend status among forest birds grouped by habitat association or migratory guild, although all 5 aerial insectivore species have declined. Better monitoring coverage of the boreal will be needed if improved reliability of trends is desired in the near future. Key words: Ontario, forest birds, boreal forest, population trend, bird surveys, monitoring reliability
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Dembicz, Katarzyna. "The End of the Myth of the Cuban Exile? Current Trends in Cuban Emigration." International Studies. Interdisciplinary Political and Cultural Journal 25, no. 1 (2020): 75–88. http://dx.doi.org/10.18778/1641-4233.25.05.
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Cuban migrants are considered as and referred to as exiles. However, in the face of the economic transformations in Cuba, as well as the rapprochement between the U.S. and Cuba, it has become necessary to revise the epistemological and semiotic foundations of this phenomenon. The current migratory trends among the Cubans do not meet the definition of exiles. Thus, the title of this article reflects the research assumption and the principal aim that the current circumstances in Cuba, as well as the migratory flows of Cubans mark the decline of the myth of the Cuban exile; a myth built by the media.
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Hoffman, Stephen W., and Jeff P. Smith. "POPULATION TRENDS OF MIGRATORY RAPTORS IN WESTERN NORTH AMERICA, 1977–2001." Condor 105, no. 3 (2003): 397. http://dx.doi.org/10.1650/7146.
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Gitelman, Zvi. "RECENT DEMOGRAPHIC AND MIGRATORY TRENDS AMONG SOVIET JEWS: IMPLICATIONS FOR POLICY." Post-Soviet Geography 33, no. 3 (1992): 139–45. http://dx.doi.org/10.1080/10605851.1992.10640895.
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Chiba, Naoki. "Pacific Professional Baseball Leagues and Migratory Patterns and Trends: 1995-1999." Journal of Sport and Social Issues 28, no. 2 (2004): 193–211. http://dx.doi.org/10.1177/0193723504264773.
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Hoffman, Stephen W., and Jeff P. Smith. "Population Trends of Migratory Raptors in Western North America, 1977–2001." Condor 105, no. 3 (2003): 397–419. http://dx.doi.org/10.1093/condor/105.3.397.
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Abstract Trained observers counted migrating raptors and vultures from ridgetops at six sites in the Intermountain and Rocky Mountain Flyways of western North America: Goshute Mountains, Nevada (autumn 1983–2001); Wellsville Mountains, Utah (autumn 1977–1979 and 1987–2001); Bridger Mountains, Montana (autumn 1992–2001); Manzano Mountains, New Mexico (autumn 1985–2001); Sandia Mountains, New Mexico (spring 1985–2001); and Lipan Point, Arizona (autumn 1991–2001). We analyzed site-specific trends in annual passage rates (raptors per 100 hr of observation), conducting species-level analyses for 13 species and age-specific analyses for Northern Goshawks (Accipiter gentilis) and Golden Eagles (Aquila chrysaetos). Our findings suggest that, until the late 1990s when possibly drought-related downturns began, Intermountain–Rocky Mountain populations of Turkey Vultures (Cathartes aura), Ospreys (Pandion haliaetus), Broad-winged Hawks (Buteo platypterus), Red-tailed Hawks (B. jamaicensis), Merlins (Falco columbarius), and Peregrine Falcons (F. peregrinus) were increasing for diverse reasons. In contrast, our migration data and other sources indicate concern over the status of western Golden Eagles and Ferruginous Hawks (B. regalis), and uncertainty about the status of western Northern Goshawks and American Kestrels (F. sparverius). Breeding Bird Survey and Christmas Bird Count trends generally corroborated our results. The migration data reveal regional variation in the status of some species, give new insight concerning Golden Eagle and Northern Goshawk migrations, and suggest effects of an ongoing, widespread drought. Our analyses demonstrate the value of standardized, long-term migration counts for monitoring the regional status and trends of migratory raptors in western North America. Tendencias Poblacionales de Aves Rapaces Migratorias en el Oeste de Norte América Entre 1977 y 2001 Resumen. Varios observadores entrenados contaron aves rapaces migratorias desde las cimas de montañas en seis sitios en los corredores de vuelo inter-montañas y de las Montañas Rocallosas en el oeste de Norte América: Goshute Mountains, Nevada (otoño 1983–2001); Wellsville Mountains, Utah (otoño 1977–1979 y 1987–2001); Bridger Mountains, Montana (otoño 1992–2001); Manzano Mountains, New Mexico (otoño 1985–2001); Sandia Mountains, New Mexico (primavera 1985–2001); Lipan Point, Arizona (otoño 1991–2001). Analizamos las tendencias específicas de cada sitio en las tasas anuales de paso (número de rapaces por 100 hr de observación), realizando análisis por especie para 13 especies y por edad para las especies Accipiter gentilis y Aquila chrysaetos. Nuestros hallazgos sugieren que hasta finales de los años 1990s (cuando comenzaron a verse tendencias negativas posiblemente relacionadas con sequías) las poblaciones de Cathartes aura, Pandion haliaetus, Buteo platypterus, B. jamaicensis, Falco columbarius y F. peregrinus estaban aumentando por diversos motivos. En contraste, nuestros datos de migración y otras fuentes causan preocupación en cuanto al estatus de A. chrysaetos y B. regalis, e incertidumbre sobre el estatus de A. gentilis y F. sparverius. Las tendencias evidentes en los censos de aves reproductivas y los conteos navideños generalmente corroboraron nuestros resultados. Los datos de migración mostraron la existencia de variación regional en el estatus de algunas especies, revelaron información nueva con respecto a las migraciones de A. chrysaetos y A. gentilis e indicaron los efectos de una sequía actual generalizada. Nuestros análisis demuestran el valor de conteos estandarizados de aves rapaces migratorias a largo plazo para monitorear el estatus regional y las tendencias poblacionales de estas aves en el oeste de Norte América.
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Matsyura, О. V., та D. V. Zhdanova. "АНАЛІЗ ВАРІАЦІЇ ЧИСЕЛЬНОСТІ МІГРУЮЧИХ ПТАХІВ". Biological Bulletin of Bogdan Chmelnitskiy Melitopol State Pedagogical University 2, № 1 (2012): 96. http://dx.doi.org/10.15421/20122_10.
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<p>The technical approach developed for the estimation of migratory birds population trends was presented|. The review of applied software that can be implemented in the analysis of population trends was done|. The suggested models could be used in analysis and prognosis of birds abundance.</p>
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Freshwater, Cameron, Brian J. Burke, Mark D. Scheuerell, Sue C. H. Grant, Marc Trudel, and Francis Juanes. "Coherent population dynamics associated with sockeye salmon juvenile life history strategies." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 8 (2018): 1346–56. http://dx.doi.org/10.1139/cjfas-2017-0251.
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Although the importance of diversity to maintaining metapopulation stability is widely recognized, the ecological characteristics that lead to synchronous dynamics within population aggregates are often unclear. We used a constrained dynamic factor analysis to explore patterns of covariance in productivity among 16 Fraser River sockeye salmon (Oncorhynchus nerka) conservation units (CUs). Specifically, we tested whether coherent trends in productivity covaried with five distinct ecological attributes: physical characteristics of nursery lakes, large-scale management interventions, genetic similarity, adult migration phenology, or juvenile migratory traits. The top-ranked model had two trends based on nursery lake characteristics and juvenile migratory traits. One trend represented the dynamics of CUs that rear in nursery lakes prior to ocean entry and undergo relatively rapid marine migrations. The second included a sea-type CU, Harrison River, which enters the marine environment without rearing in a nursery lake and migrates more slowly. The uniform response of lake-type CUs, as well as Harrison River CU’s unique life history, suggests that coherent trends are structured by traits that covary with broad life history type, rather than fine-scale characteristics. Furthermore, we document substantial temporal variability in the strength of synchronous dynamics among Fraser River CUs. Greater synchrony in recent years suggests that the importance of shared regional drivers, relative to local processes, may have increased.
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Lynch, Patrick D., Kyle W. Shertzer, Enric Cortés, and Robert J. Latour. "Abundance trends of highly migratory species in the Atlantic Ocean: accounting for water temperature profiles." ICES Journal of Marine Science 75, no. 4 (2018): 1427–38. http://dx.doi.org/10.1093/icesjms/fsy008.
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Abstract Relative abundance trends of highly migratory species (HMS) have played a central role in debates over the health of global fisheries. However, such trends have mostly been inferred from fishery catch rates, which can provide misleading signals of relative abundance. While many biases are accounted for through traditional catch rate standardization, pelagic habitat fished is rarely directly considered. Using a method that explicitly accounts for temperature regimes, we analysed data from the US pelagic longline fishery to estimate relative abundance trends for 34 HMS in the Atlantic Ocean from 1987 through 2013. This represents one of the largest studies of HMS abundance trends. Model selection emphasized the importance of accounting for pelagic habitat fished with water column temperature being included in nearly every species’ model, and in extreme cases, a temperature variable explained 50–60% of the total deviance. Our estimated trends represent observations from one fishery only, and a more integrated stock assessment should form the basis for conclusions about stock status overall. Nonetheless, our trends serve as indicators of stock abundance and they suggest that a majority of HMS (71% of analysed species) are either declining in relative abundance or declined initially with no evidence of rebuilding. Conversely, 29% of the species exhibited stable, increasing, or recovering trends; however, these trends were more prevalent among tunas than either billfishes or sharks. By estimating the effects of pelagic habitat on fishery catch rates, our results can be used in combination with ocean temperature trends and forecasts to support bycatch avoidance and other time-area management decisions.
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Murphy, Michael T. "Avian Population Trends Within the Evolving Agricultural Landscape of Eastern and Central United States." Auk 120, no. 1 (2003): 20–34. http://dx.doi.org/10.1093/auk/120.1.20.
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Abstract State-level Breeding Bird Survey (1980–1998) and U.S. Department of Agriculture statistics were used to test the hypothesis that changes in agricultural land use within the eastern and central U.S. have driven population trends of grassland and shrub habitat birds over the past two decades. The degree to which population trends differed between grassland and shrub habitats was evaluated with respect to migratory and nesting behavior. Grassland birds declined significantly between 1980 and 1999, but, on average, shrub habitat species did not. Grassland-breeding, long-distance migrants exhibited the strongest negative trends. Most species (78%; n = 63) exhibited at least one significant association between population trends and changes in agricultural land use, and in most, land use “explained” 25–30% of the variation in population trends among states. Changes in the farmland landscape accounted for more of the interstate variability of population trends of short-distance migrants than of both long-distance migrants and residents, and that variability was greater in grassland than shrub species. Declines in the area of rangeland and cover crops were followed by population declines and increases, respectively, by many species. Increases of land in the Conservation Reserve Program had negative associations with population trends of some shrub species. The results indicate that grassland birds have declined strongly over the past two decades, and that regardless of migratory behavior or nesting habits, avian population trends are linked strongly to changes in agricultural land use within North America.
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Granados Alcántar, José Aurelio. "Las corrientes migratorias en las ciudades contiguas a la Zona Metropolitana de la Ciudad de México: el caso de la aglomeración urbana de Pachuca / Migratory Trends in Cities Adjacent to the Mexico City Metropolitan Area. The Case of Urban Agglomeration i." Estudios Demográficos y Urbanos 22, no. 3 (2007): 619. http://dx.doi.org/10.24201/edu.v22i3.1273.
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En los últimos veinte años la ciudad de Pachuca ha sufrido grandes transformaciones en su territorio; el ritmo de crecimiento poblacional ha provocado que la ciudad se expanda físicamente como no lo había hecho en sus casi quinientos años de existencia. Una parte de este crecimiento poblacional se debe a los procesos inmigratorios que han ocurrido en los últimos años. Tomando en cuenta las tendencias y las experiencias de otras ciudades contiguas a la Zona Metropolitana de la Ciudad de México, pensamos que el actual flujo migratorio se consolidará e intensificará en los próximos años. De ahí que el objetivo del presente trabajo sea realizar un estudio sobre las corrientes migratorias en el espacio urbano de Pachuca, describiendo el perfil del migrante según los flujos establecidos. Nos interesa prever los cambios económicos y sociales en la ciudad, el desarrollo de su influencia regional y su nuevo papel en el sistema de ciudades y en la megalópolis de la Ciudad de México. AbstractOver the past twenty years, the city of Pachuca has undergone enormous transformations in its territory while the rate of population growth has meant that the city has expanded more than ever before in its nearly 500 years of existence. Part of this population growth is due to the migratory processes that have taken place in recent years. Given the trends and experiences of other cities adjacent to the Mexico City Metropolitan Zone, the authors believe that the current migratory flow will be consolidated and intensified over the next few years. The aim of this study is to therefore to undertake a study of migratory trends in the urban space of Pachuca, by describing migrants’ profiles according to the established flows. The authors are interested in predicting the economic and social changes in the city, the development of its regional influence and its new role in the system of cities and the Mexico City megalopolis.
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Micelli, Ezio. "The intercultural city: real estate markets, migratory trends and social dynamics [La città interculturale: dinamiche immobiliari, migratorie e sociali]." Valori e Valutazioni 28 (July 2021): 59–66. http://dx.doi.org/10.48264/vvsiev-20212806.
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New ethnicities and new cultures are taking up residence in our cities: for years the flow of foreign people has been compensating the decreasing rates of natural growth and population ageing. This trend comes along with several consequences in the real estate market, and the scientific literature has shown up events in common with many countries. Spatial segregation, as a consequence of real estate dynamics, has to be critically evaluated: it is by no means a neutral mechanism, yet it contributes in no small measure to the spatial segregation of the smaller communities. Nuove etnie e nuove culture abitano le nostre città: da anni il flusso di persone straniere compensa il decrescente saldo naturale e l’invecchiamento della popolazione. Ciò non è senza conseguenze sul mercato immobiliare e la letteratura scientifica mette in luce fenomeni comuni a molti paesi. La segregazione spaziale effetto di dinamiche di mercato va considerata criticamente: quest’ultimo non è dispositivo neutrale, ma concorre attivamente alla segregazione spaziale delle comunità.
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Bastille-Rousseau, Guillaume, James A. Schaefer, Shane P. Mahoney, and Dennis L. Murray. "Population decline in semi-migratory caribou (Rangifer tarandus): intrinsic or extrinsic drivers?" Canadian Journal of Zoology 91, no. 11 (2013): 820–28. http://dx.doi.org/10.1139/cjz-2013-0154.
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Many populations of caribou (Rangifer tarandus (L., 1758)) across North America, including Newfoundland, are in a state of decline. This phenomenon may reflect continental-scale changes in either the extrinsic or the intrinsic factors affecting caribou abundance. We hypothesized that caribou decline reflected marked resource limitation and predicted that fluctuations should correspond to time-delayed density dependence associated with a decline in range quality and decadal trends in winter severity. By conducting time-series analysis using 12 populations and evaluating correlations between caribou abundance and trends in (i) vegetation available at calving (normalized difference vegetation index, NDVI), (ii) winter weather severity (index of North Atlantic Oscillation, NAO), and (iii) caribou morphometrics, we observed strong evidence of density dependence in population dynamics (i.e., a negative relationship between caribou population size and caribou morphometrics). Caribou population trajectories were time-delayed relative to winter severity, but not relative to calving-ground greenness. These island-wide correlations could not be traced to dispersal between herds, which appears rare at least for adult females. Our results suggest that trends in winter severity may synchronize broad-scale changes in caribou abundance that are driven by time-delayed density dependence, although it remains possible that calving-ground deterioration also may contribute to population limitation in Newfoundland. Our findings provide the basis for additional research into density dependence and caribou population decline.
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Guy, Judith, and John Switzer. "The Migratory Trends of International Baccalaureate Diploma Students in Asia Pacific: Going Global?" Journal of the World Universities Forum 3, no. 5 (2010): 59–74. http://dx.doi.org/10.18848/1835-2030/cgp/v03i05/56705.
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Tinker, Catherine Jane, and Laura Madrid Sartoretto. "New trends in migratory and refugee law in Brazil: the expanded refugee definition." Revista do Direito 3, no. 50 (2016): 118–38. http://dx.doi.org/10.17058/rdunisc.v3i50.8277.
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This paper aims to explore new trends in Brazilian refugee and migratory law in the last 20 years. In doing so it addresses the evolution of the definition of “refugee” in Brazil, expanding the eligibility grounds provided by the 1951 Geneva Convention on the Status of Refugees (1951 Convention). Reviewing international and regional refugee law, the article analyzes the broader understanding of the notion of "refuge" and its complexity expressed in regional and national legal frameworks, taking account of lawyers, scholars and activists who criticize the narrow scope of the classical refugee definition from 1951 which has become distant from current refugee voices and struggles. At the domestic level, although the 1980 Aliens Statute (Act. n. 6815/80) is still in effect, there have been important changes in refugee law in Brazil since the implementation of the 1997 Refugee Statute (Act n. 9.474/97), influenced by the 1984 Cartagena Declaration (a regional soft law instrument) regarding the definition of “refugee”, Exploring the interconnection of the Refugee Statute and complementary forms of human rights protection which fall outside the scope of international refugee law, the article concludes that in the specific case of Haitians in Brazil, the broader protections of Brazilian refugee law should be available rather than the complementary system of humanitarian visas.
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Morrison, Catriona A., Robert A. Robinson, Jacquie A. Clark, and Jennifer A. Gill. "Spatial and temporal variation in population trends in a long-distance migratory bird." Diversity and Distributions 16, no. 4 (2010): 620–27. http://dx.doi.org/10.1111/j.1472-4642.2010.00663.x.
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Tinker, Catherine, and Laura Madrid Sartoretto. "NEW TRENDS IN MIGRATORY AND REFUGEE LAW IN BRAZIL: THE EXPANDED REFUGEE DEFINITION." Panorama of Brazilian Law 3, no. 3-4 (2015): 143–69. http://dx.doi.org/10.17768/pbl.a3.n3-4.p143.
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Tinker, Catherine, and Laura Madrid Sartoretto. "NEW TRENDS IN MIGRATORY AND REFUGEE LAW IN BRAZIL: THE EXPANDED REFUGEE DEFINITION." PANORAMA OF BRAZILIAN LAW 3, no. 3-4 (2018): 143–69. http://dx.doi.org/10.17768/pbl.v3i3-4.34406.
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This paper aims to explore new trends in Brazilian refugee and migratory law in the last 20 years. In doing so it addresses the evolution of the definition of “refugee” in Brazil, expanding the eligibility grounds provided by the 1951 Geneva Convention on the Status of Refugees (1951 Convention). Reviewing international and regional refugee law, the article analyzes the broader understanding of the notion of “refuge” and its complexity expressed in regional and national legal frameworks, taking account of lawyers, scholars and activists who criticize the narrow scope of the classical refugee definition from 1951 which has become distant from current refugee voices and struggles. At the domestic level, although the 1980 Aliens Statute (Act. n. 6815/80) is still in effect, there have been important changes in refugee law in Brazil since the implementation of the 1997 Refugee Statute (Act n. 9.474/97), influenced by the 1984 Cartagena Declaration (a regional soft law instrument) regarding the definition of “refugee”. Exploring the interconnection of the Refugee Statute and complementary forms of human rights protection which fall outside the scope of international refugee law, the article concludes that in the specific case of Haitians in Brazil, the broader protections of Brazilianrefugee law should be available rather than the complementary systemof humanitarian visas.
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Tinker, Catherine, and Laura Madrid Sartoretto. "NEW TRENDS IN MIGRATORY AND REFUGEE LAW IN BRAZIL: THE EXPANDED REFUGEE DEFINITION." PANORAMA OF BRAZILIAN LAW 3, no. 3-4 (2018): 143–69. http://dx.doi.org/10.17768/pbl.v3i3-4.p143-169.
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This paper aims to explore new trends in Brazilian refugee and migratory law in the last 20 years. In doing so it addresses the evolution of the definition of “refugee” in Brazil, expanding the eligibility grounds provided by the 1951 Geneva Convention on the Status of Refugees (1951 Convention). Reviewing international and regional refugee law, the article analyzes the broader understanding of the notion of “refuge” and its complexity expressed in regional and national legal frameworks, taking account of lawyers, scholars and activists who criticize the narrow scope of the classical refugee definition from 1951 which has become distant from current refugee voices and struggles. At the domestic level, although the 1980 Aliens Statute (Act. n. 6815/80) is still in effect, there have been important changes in refugee law in Brazil since the implementation of the 1997 Refugee Statute (Act n. 9.474/97), influenced by the 1984 Cartagena Declaration (a regional soft law instrument) regarding the definition of “refugee”. Exploring the interconnection of the Refugee Statute and complementary forms of human rights protection which fall outside the scope of international refugee law, the article concludes that in the specific case of Haitians in Brazil, the broader protections of Brazilianrefugee law should be available rather than the complementary systemof humanitarian visas.
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Tinker, Catherine, and Laura Madrid Sartoretto. "NEW TRENDS IN MIGRATORY AND REFUGEE LAW IN BRAZIL: THE EXPANDED REFUGEE DEFINITION." PANORAMA OF BRAZILIAN LAW 3, no. 3-4 (2015): 143–69. http://dx.doi.org/10.17768/pbl.y3.n3-4.p143-169.
Full textAbstract:
This paper aims to explore new trends in Brazilian refugee and migratory law in the last 20 years. In doing so it addresses the evolution of the definition of “refugee” in Brazil, expanding the eligibility grounds provided by the 1951 Geneva Convention on the Status of Refugees (1951 Convention). Reviewing international and regional refugee law, the article analyzes the broader understanding of the notion of “refuge” and its complexity expressed in regional and national legal frameworks, taking account of lawyers, scholars and activists who criticize the narrow scope of the classical refugee definition from 1951 which has become distant from current refugee voices and struggles. At the domestic level, although the 1980 Aliens Statute (Act. n. 6815/80) is still in effect, there have been important changes in refugee law in Brazil since the implementation of the 1997 Refugee Statute (Act n. 9.474/97), influenced by the 1984 Cartagena Declaration (a regional soft law instrument) regarding the definition of “refugee”. Exploring the interconnection of the Refugee Statute and complementary forms of human rights protection which fall outside the scope of international refugee law, the article concludes that in the specific case of Haitians in Brazil, the broader protections of Brazilianrefugee law should be available rather than the complementary systemof humanitarian visas.
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Tinker, Catherine, and Laura Madrid Sartoretto. "NEW TRENDS IN MIGRATORY AND REFUGEE LAW IN BRAZIL: THE EXPANDED REFUGEE DEFINITION." PANORAMA OF BRAZILIAN LAW 3, no. 3-4 (2018): 143–69. http://dx.doi.org/10.17768/pbl.y3n3-4.p143-169.
Full textAbstract:
This paper aims to explore new trends in Brazilian refugee and migratory law in the last 20 years. In doing so it addresses the evolution of the definition of “refugee” in Brazil, expanding the eligibility grounds provided by the 1951 Geneva Convention on the Status of Refugees (1951 Convention). Reviewing international and regional refugee law, the article analyzes the broader understanding of the notion of “refuge” and its complexity expressed in regional and national legal frameworks, taking account of lawyers, scholars and activists who criticize the narrow scope of the classical refugee definition from 1951 which has become distant from current refugee voices and struggles. At the domestic level, although the 1980 Aliens Statute (Act. n. 6815/80) is still in effect, there have been important changes in refugee law in Brazil since the implementation of the 1997 Refugee Statute (Act n. 9.474/97), influenced by the 1984 Cartagena Declaration (a regional soft law instrument) regarding the definition of “refugee”. Exploring the interconnection of the Refugee Statute and complementary forms of human rights protection which fall outside the scope of international refugee law, the article concludes that in the specific case of Haitians in Brazil, the broader protections of Brazilianrefugee law should be available rather than the complementary systemof humanitarian visas.
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Gillanders, Bronwyn M., Christopher Izzo, Zoë A. Doubleday, and Qifeng Ye. "Partial migration: growth varies between resident and migratory fish." Biology Letters 11, no. 3 (2015): 20140850. http://dx.doi.org/10.1098/rsbl.2014.0850.
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Partial migration occurs in many taxa and ecosystems and may confer survival benefits. Here, we use otolith chemistry data to determine whether fish from a large estuarine system were resident or migratory, and then examine whether contingents display differences in modelled growth based on changes in width of otolith growth increments. Sixty-three per cent of fish were resident based on Ba : Ca of otoliths, with the remainder categorized as migratory, with both contingents distributed across most age/size classes and both sexes, suggesting population-level bet hedging. Migrant fish were in slightly better condition than resident fish based on Fulton's K condition index. Migration type (resident versus migratory) was 56 times more likely to explain variation in growth than a model just incorporating year- and age-related growth trends. While average growth only varied slightly between resident and migratory fish, year-to-year variation was significant. Such dynamism in growth rates likely drives persistence of both life-history types. The complex relationships in growth between contingents suggest that management of species exhibiting partial migration is challenging, especially in a world subject to a changing climate.
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Fikadu Tolossa Ayanie, Dagnachew T. Melese, Eyayew T. Beze, and Tihtina A. Fanta. "Trends in Contemporary International Migration of Ethiopia." PanAfrican Journal of Governance and Development (PJGD) 1, no. 2 (2020): 30–60. http://dx.doi.org/10.46404/panjogov.v1i2.2342.
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Ethiopia is found in the ‘Eastern Africa migration system’ known for turbulent population mobility due to a host of social, economic, and political factors. The migration problem of East Africa, in which, a substantial exploration of the complexity and intensity of the migration pattern of Ethiopia has become necessary in the context of social transformation and development processes. To this end, this study is designed to provide migratory change and developmental patterns of international migration of Ethiopia in regional and sub-regional perspectives based on long-term macro statistics. The data obtained from the Reports of the United Nations Department for Economic and Social Affairs and World Bank’s Development Indicators have been used to describe, analyze and explain long-term patterns of international migration of Ethiopia within the regional contexts. Results show the trend that Ethiopia experienced a continuous increase in its international migrant stock in the last five decades, from less than 400,000 in 1960 to over 1 million in 2015. Refugees and transit migrants constituted the largest number of immigrants, mostly from the neighboring countries, driven by continuous conflicts and political instability. Ethiopia, once dominant in refugee flows in the Horn of Africa due to political conflict, famine, and persecution, experienced a sharp decline in the share of refugees in the Horn of Africa in the last three decades. Economic motives have recently become the prime factors in migration decisions among the Ethiopians as observed with the fact that the USA and the Middle East are the major destinations. The findings revealed that Ethiopian emigration is characterized by the inter-continental flows unlike the Sub-Saharan migration pattern known to have an intra-continental migratory link. Feminization of Ethiopian migration is also evident particularly in core destination countries of the Global North, which indicates the increasing role of females in migration decisions but also disproves the widely held perception about Ethiopians emigration to the Arab World as female-specific. In the final analysis, Ethiopia could be regarded rather as a destination, with over 1.2 million migrants, than as an origin, with just over 800,000 as of 2017, which now make the country a regional migration hub in the Horn of Africa.
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Robinson, W. Douglas, Christina Partipilo, Tyler A. Hallman, Karan Fairchild, and James P. Fairchild. "Idiosyncratic changes in spring arrival dates of Pacific Northwest migratory birds." PeerJ 7 (November 7, 2019): e7999. http://dx.doi.org/10.7717/peerj.7999.
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Shifts in the timing of bird migration have been associated with climatic change and species traits. However, climatic change does not affect all species or geographic locations equally. Climate in the Pacific Northwest has shifted during the last century with mean temperatures increasing by 1 °C but little change in total annual precipitation. Few long-term data on migration phenology of birds are available in the Pacific Northwest. We analyzed trends in spring arrival dates from a site in the Oregon Coast Range where nearly daily inventories of birds were conducted in 24 of 29 years. Several species showed statistically significant shifts in timing of first spring arrivals. Six of 18 species occur significantly earlier now than during the initial phase of the study. One species arrives significantly later. Eleven show no significant shifts in timing. We associated trends in spring migration phenology with regional climatic variables, weather (precipitation and temperature), traits of species such as migration strategy, foraging behavior, diet, and habitat use, and regional trends in abundance as indexed by Breeding Bird Survey data. We found no set of variables consistently correlated with avian phenological changes. Post hoc analyses of additional climate variables revealed an association of migratory arrival dates across the 18 species with rainfall totals in northern California, presumably indicating that songbird arrival dates in Oregon are slowed by spring storm systems in California. When only the six species with the most strongly advancing arrival dates were analyzed, winter maximum temperatures in the preceding three winters appeared consistently in top models, suggesting a possible role for food availability early in spring to promote the survival and successful reproduction of the earliest-arriving birds. However, additional data on food availability and avian survival and reproductive success are required to test that hypothesis. Despite the appearance of some climate variables in top models, there remains a mismatch between strongly advancing arrival dates in some songbirds and a lack of clear directional change in those climate variables. We conclude that either some previously unrecognized variable or combination of variables has affected the timing of migration in some species but not others, or the appearance of statistically significant directional changes over time can occur without being driven by consistent environmental or species-specific factors.
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De Ruyck, Christopher C., James Duncan, and Nicola Koper. "Northern Saw-Whet Owl (Aegolius acadicus) Migratory Behavior, Demographics, and Population Trends in Manitoba." Journal of Raptor Research 46, no. 1 (2012): 84–97. http://dx.doi.org/10.3356/jrr-10-30.1.
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Doyle, Susan, David Cabot, Alyn Walsh, Richard Inger, Stuart Bearhop, and Barry J. McMahon. "Temperature and precipitation at migratory grounds influence demographic trends of an Arctic‐breeding bird." Global Change Biology 26, no. 10 (2020): 5447–58. http://dx.doi.org/10.1111/gcb.15267.
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Saunders, Sarah P., Leslie Ries, Naresh Neupane, et al. "Multiscale seasonal factors drive the size of winter monarch colonies." Proceedings of the National Academy of Sciences 116, no. 17 (2019): 8609–14. http://dx.doi.org/10.1073/pnas.1805114116.
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Monarch butterflies in eastern North America have declined by 84% on Mexican wintering grounds since the observed peak in 1996. However, coarse-scale population indices from northern US breeding grounds do not show a consistent downward trend. This discrepancy has led to speculation that autumn migration may be a critical limiting period. We address this hypothesis by examining the role of multiscale processes impacting monarchs during autumn, assessed using arrival abundances at all known winter colony sites over a 12-y period (2004–2015). We quantified effects of continental-scale (climate, landscape greenness, and disease) and local-scale (colony habitat quality) drivers of spatiotemporal trends in winter colony sizes. We also included effects of peak summer and migratory population indices. Our results demonstrate that higher summer abundance on northern breeding grounds led to larger winter colonies as did greener autumns, a proxy for increased nectar availability in southern US floral corridors. Colony sizes were also positively correlated with the amount of local dense forest cover and whether they were located within the Monarch Butterfly Biosphere Reserve, but were not influenced by disease rates. Although we demonstrate a demographic link between summer and fine-scale winter population sizes, we also reveal that conditions experienced during, and at the culmination of, autumn migration impact annual dynamics. Monarchs face a growing threat if floral resources and winter habitat availability diminish under climate change. Our study tackles a long-standing gap in the monarch’s annual cycle and highlights the importance of evaluating migratory conditions to understand mechanisms governing long-term population trends.
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Gardali, Thomas, Grant Ballard, Nadav Nur, and Geoffrey R. Geupel. "Demography of a Declining Population of Warbling Vireos in Coastal California." Condor 102, no. 3 (2000): 601–9. http://dx.doi.org/10.1093/condor/102.3.601.
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Abstract We investigated population trends, adult survival, and productivity indices of a breeding population of Warbling Vireos (Vireo gilvus) in north coastal California using capture-recapture data from 19 years of standardized mist-netting conducted at Point Reyes National Seashore. We found significant long-term declines in abundance of both breeding and migratory Warbling Vireos. In addition, we found a significant long-term decline of hatching-year birds captured during the breeding season. The number of new adults in a given year, defined as those birds not previously banded and assumed to be an index of adult recruitment, was significantly correlated with the capture rate of hatching-year birds in the previous year, suggesting a link between reproductive success and adult abundance and recruitment. Our analysis of capture-recapture data provided an estimate of 50.4% for adult annual survival, similar to estimates for other species in stable populations. We could detect no temporal trend in survival. Nest survivorship from areas near our netting site was relatively low. We suggest that the decline of breeding and migratory populations of Warbling Vireos observed in coastal California may be the result of low productivity on the breeding grounds.
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Bowlin, Melissa S. "Sex, Wingtip Shape, and Wing-Loading Predict Arrival Date at a Stopover Site in the Swainson's Thrush (Catharus Ustulatus)." Auk 124, no. 4 (2007): 1388–96. http://dx.doi.org/10.1093/auk/124.4.1388.
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Abstract Pointed wingtips and low wing-loading are believed to reduce the amount of energy used during migratory flight. If this is true, individuals with pointed wingtips or consistently low wing-loading should be able to migrate faster than conspecifics and may arrive on the breeding grounds and at stopover sites earlier. To test this hypothesis, I captured 97 Swainson's Thrushes (Catharus ustulatus; hereafter “thrushes”) during May in three consecutive field seasons, 2003-2005, at a stopover site in central Illinois. I used molecular techniques to sex 47 of these thrushes and created a discriminant function analysis using wing, tarsometatarsus, and tail lengths that predicted sex with 80.9% accuracy (P < 0.001). I applied this function to the remaining 50 thrushes so that I could control for any sexual dimorphism in morphology and arrival timing, and then examined seasonal trends in sex and morphology. Male thrushes arrived earlier at my stopover site than females (P < 0.001). After controlling for sex, thrushes with more pointed wingtips (P = 0.002) and lower wing-loading (P = 0.044) arrived earlier than thrushes with more rounded wingtips and higher wing-loading. The general linear model with sex, wingtip pointedness, and wing-loading explained nearly one-third of the variation in arrival date (P < 0.001, r2 = 0.281, n = 90). Pointed wingtips and lower wing-loading may help migratory birds cover distance more quickly and arrive at the breeding grounds sooner; alternatively, thrushes with more pointed wingtips and lower wing-loading may have departed from the wintering grounds earlier. If wing shape and size affect rate of migration, these variables may be important determinants of individual quality in migratory passerines. El Sexo, la Forma de las Puntas de las Alas y la Carga Alar Predicen la Fecha de Arribo de Catharus ustulatus a un Sitio de Escala Migratoria
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Nilsson, Sven G., Ola Olsson, Sören Svensson, and Ulf Wiktander. "Population trends and fluctuations in Swedish woodpeckers." Ornis Svecica 2, no. 1 (1992): 13–21. http://dx.doi.org/10.34080/os.v2.22398.
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This is a quantitative study of population changes in four non-migratory woodpeckers in Sweden. Data were collected during five periods from late autumn to spring and during the breeding season, mainly using point counts. Most analyses are based on the proportion of the routes (each with 20 points) with observation of the species in each year. From 1975 to 1991 there were no population trends in the Great Spotted and Black Woodpeckers, but decreases in the Green and Lesser Spotted Woodpeckers. The mean annual decrease was about 2% in the Green and 4% in the Lesser Spotted Woodpecker. There was no trend in winter weather over this period, and only for the Black Woodpecker we found associations between mild winters and numbers recorded. The Great Spotted Woodpecker population increased in years with a high spruce seed supply. In southernmost Sweden frequency of observation was higher for the Green and, in winter, for the Black Woodpecker than further north, while the reverse was true for the Great Spotted Woodpecker. No regional difference was found for the Lesser Spotted Woodpecker.
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Rushing, Clark S., J. Andrew Royle, David J. Ziolkowski, and Keith L. Pardieck. "Migratory behavior and winter geography drive differential range shifts of eastern birds in response to recent climate change." Proceedings of the National Academy of Sciences 117, no. 23 (2020): 12897–903. http://dx.doi.org/10.1073/pnas.2000299117.
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Over the past half century, migratory birds in North America have shown divergent population trends relative to resident species, with the former declining rapidly and the latter increasing. The role that climate change has played in these observed trends is not well understood, despite significant warming over this period. We used 43 y of monitoring data to fit dynamic species distribution models and quantify the rate of latitudinal range shifts in 32 species of birds native to eastern North America. Since the early 1970s, species that remain in North America throughout the year, including both resident and migratory species, appear to have responded to climate change through both colonization of suitable area at the northern leading edge of their breeding distributions and adaption in place at the southern trailing edges. Neotropical migrants, in contrast, have shown the opposite pattern: contraction at their southern trailing edges and no measurable shifts in their northern leading edges. As a result, the latitudinal distributions of temperate-wintering species have increased while the latitudinal distributions of neotropical migrants have decreased. These results raise important questions about the mechanisms that determine range boundaries of neotropical migrants and suggest that these species may be particularly vulnerable to future climate change. Our results highlight the potential importance of climate change during the nonbreeding season in constraining the response of migratory species to temperature changes at both the trailing and leading edges of their breeding distributions. Future research on the interactions between breeding and nonbreeding climate change is urgently needed.
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Fleischer, Shelby, Greg Payne, Thomas Kuhar, et al. "Helicoverpa zea Trends from the Northeast: Suggestions Towards Collaborative Mapping of Migration and Pyrethroid Susceptibility." Plant Health Progress 8, no. 1 (2007): 58. http://dx.doi.org/10.1094/php-2007-0719-03-rv.
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In the northeastern US, sweet corn is attacked by three lepidopterans, two of which are primarily migrants from the south. Knowledge about when and where these immigrants arrive can dramatically reduce insecticide inputs. We discuss progress on monitoring for pyrethroid resistance in one of the migrants, Helicoverpa zea, and in developing interactive cartography for regional monitoring of migratory lepidopterans in the northeastern US. Accepted for publication 14 November 2006. Published 19 July 2007.
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Jonzén, Niclas, Anders Hedenström, and Per Lundberg. "Climate change and the optimal arrival of migratory birds." Proceedings of the Royal Society B: Biological Sciences 274, no. 1607 (2006): 269–74. http://dx.doi.org/10.1098/rspb.2006.3719.
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Recent climate change has sparked an interest in the timing of biological events, which is a general problem in life-history evolution. Reproduction in many organisms breeding in seasonal environments, e.g. migratory birds, is dependent on the exploitation of a short but rich food supply. If the seasonal timing of the food peak advances owing to climate change, then one would expect the bird to track those changes, hence, initiate migration and breeding earlier. However, when there is competition for territories and a risk of pre-breeding mortality, the optimal response to a shifting food distribution is no longer obvious. We develop a theoretical model to study how the optimal arrival time depends on the mean and variance of the food distribution, the degree of competition for territories and the risk of mortality. In general, the optimal shift in arrival date should never be as extreme as the shift in food peak date. Our results also show that we should expect the high variation of trends in arrival date observed among migratory birds, even if migration and information about climate change were unconstrained.
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Patsiorkovskiy, Valery V., Yuriy A. Simagin, and Dzhamilya D. Murtuzalieva. "The population dynamic in Russian municipal formations from 2010 to 2018." VESTNIK INSTITUTA SOTZIOLOGII 30, no. 3 (2019): 59–77. http://dx.doi.org/10.19181/vis.2019.30.3.589.
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During the period from the end of 2010 and up to the beginning of 2018, after a long pause, we saw an increase in the population of the Russian Federation. Meanwhile, on most of the country’s territory the population has not ceased to decline in recent years. This is very apparent when analyzing the demographic situation on the level of first order municipalities – city districts and municipal areas. Indexes of natural population growth during recent years have exceeded values from the first decade of the 21st century. However, in 80% of municipalities a negative dynamic is evident compared to 2010, primarily due to natural decline. Natural decline is often accompanied by a negative balance in the migratory flow of the population. As a result, depopulation in certain cases reaches catastrophic proportions – at over 2% each year. This article examines peculiarities in the differentiation of natural population increase and migratory flow of Russia’s population by city district, municipal area, and broken down by territory (as in by federal district). It was revealed that negative trends are more inherent to municipal areas than they are to city districts. The most complicated situation with indexes of death rate and birthrate can be observed in municipalities of the Central, North-West and Privolzhsky Federal Districts. Mostly due to an intense migratory outflow, the population is decreasing in many municipal formations of the Far Eastern Federal District. As was the case in previous decades, the most favorable demographic situation can be observed in the North Caucasian Federal District. Meanwhile its municipal formations are gradually approaching the rest of Russia in terms of population birthrate and death rate indexes. Though this trend is of ambiguous nature, since, on the one hand, it evens out the excessive interregional socio-economic differentiation we see in Russia, while on the other it has a negative effect on the country’s demographic development in general. The migratory outflow of the population from the majority of North Caucasian municipal formations narrows the foundation for this region’s demographic development in the future.
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Lea, Mary-Anne, Devin Johnson, Rolf Ream, Jeremy Sterling, Sharon Melin, and Tom Gelatt. "Extreme weather events influence dispersal of naive northern fur seals." Biology Letters 5, no. 2 (2009): 252–57. http://dx.doi.org/10.1098/rsbl.2008.0643.
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Since 1975, northern fur seal ( Callorhinus ursinus ) numbers at the Pribilof Islands (PI) in the Bering Sea have declined rapidly for unknown reasons. Migratory dispersal and habitat choice may affect first-year survivorship, thereby contributing to this decline. We compared migratory behaviour of 166 naive pups during 2 years from islands with disparate population trends (increasing: Bogoslof and San Miguel Islands; declining: PI), hypothesizing that climatic conditions at weaning may differentially affect dispersal and survival. Atmospheric conditions (Bering Sea) in autumn 2005–2006 were anomalously cold, while 2006–2007 was considerably warmer and less stormy. In 2005, pups departed earlier at all sites, and the majority of PI pups (68–85%) departed within 1 day of Arctic storms and dispersed quickly, travelling southwards through the Aleutian Islands. Tailwinds enabled faster rates of travel than headwinds, a trend not previously shown for marine mammals. Weather effects were less pronounced at Bogoslof Island (approx. 400 km further south), and, at San Miguel Island, (California) departures were more gradual, and only influenced by wind and air pressure in 2005. We suggest that increasingly variable climatic conditions at weaning, particularly timing, frequency and intensity of autumnal storms in the Bering Sea, may alter timing, direction of dispersal and potentially survival of pups.
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Meller, Kalle, Anssi V. Vähätalo, Tatu Hokkanen, Jukka Rintala, Markus Piha, and Aleksi Lehikoinen. "Interannual variation and long-term trends in proportions of resident individuals in partially migratory birds." Journal of Animal Ecology 85, no. 2 (2016): 570–80. http://dx.doi.org/10.1111/1365-2656.12486.
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Bastos, Wanderley Rodrigues, Mauro de Freitas Rebelo, Márlon de Freitas Fonseca, Ronaldo de Almeida, and Olaf Malm. "A description of mercury in fishes from the Madeira River Basin, Amazon, Brazil." Acta Amazonica 38, no. 3 (2008): 431–38. http://dx.doi.org/10.1590/s0044-59672008000300006.
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Over the last 20 years several projects carried on the Madeira River basin in the Amazon produced a great amount data on total Hg concentration in different fish species. In this paper we discuss temporal trends in Hg contamination and its relation to body weight in some of those fishes, showing that even within similar groups, such as carnivorous and non-migratory fish, the interspecies variability in Hg accumulation is considerable.
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Strieder Philippsen, Juliana, Carolina Viviana Minte-Vera, Edson Kiyoshi Okada, Adriana Rosa Carvalho, and Ronaldo Angelini. "Fishers' and scientific histories: an example of consensus from an inland fishery." Marine and Freshwater Research 68, no. 5 (2017): 980. http://dx.doi.org/10.1071/mf16053.
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In this study we tested the basic premise that fishers’ knowledge provides similar perceptions about exploited stocks to data gathered by standardised monitoring in a small-scale commercial fishery. To that end, we compared temporal trends in catch and individual size for fish species between data obtained from interviews with fishers and a 25-year dataset from a landing monitoring program in the Itaipu Reservoir (Brazil). Fishers described with accuracy changes in species composition of the catches, from large migratory species of high commercial value (common before impoundment) to migratory species of low commercial value and sedentary species following damming. Temporal trends in catches reported by fishers and documented in the landing data matched for most species. Histories diverge when absolute values are involved, such as when fishers were asked to recall their largest catch. Fishers were homogeneous in their reports, indicating that instead of individual opinions, they revealed knowledge resulting from their observation and fishery experience. Fishers can be a reliable source of information for detecting changes in catches over time, especially when large-scale habitat changes have occurred within the time scale of a fisher career. Fishers may be key partners to be considered by managers in information gathering for effective management.
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Chan, Bunyeth, Peng Bun Ngor, Zeb S. Hogan, Nam So, Sébastien Brosse, and Sovan Lek. "Temporal Dynamics of Fish Assemblages as a Reflection of Policy Shift from Fishing Concession to Co-Management in One of the World’s Largest Tropical Flood Pulse Fisheries." Water 12, no. 11 (2020): 2974. http://dx.doi.org/10.3390/w12112974.
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Inland fisheries management in Cambodia has undergone two major policy reforms over the last two decades. These reforms led to the abolishment of a century-old commercial fishing lot system in 2012 and the establishment of new fish sanctuary and community fishing areas. However, the status of fisheries and fish assemblages following the reforms is not well understood. Here, we investigated the temporal changes in fish catch weight and fish assemblage structure for the period 1995–2000 before fishing lot abolishment (BLA) and for the period 2012–2015 after the removal of all fishing lots (after lot abolishment-ALA) using time-series fish catch data recorded from the Tonle Sap Lake (TSL), one of the world largest inland fisheries. We found (i) mean catch trends vary seasonally, with stable catch trends during the BLA and decreasing catch trends during the ALA and (ii) significant shifts in fish assemblage composition, notably a shift from large-bodied, migratory, and/or predatory species during the BLA toward more short-distance migratory and/or floodplain, small-bodied species during the ALA. Fishing lot abolishment coincided with substantial changes to floodplain habitats and increases in fishing pressure, threatening TSL fish stocks. Flow alterations caused by dams and climate change may exacerbate the problem. Therefore, to realize the fisheries reform objectives, it is imperative to strengthen the fisheries’ governance and management system, including effective law enforcement, institutional strengthening, improved planning, cooperation, and coordination as well as clearly defined roles and responsibilities among concerned stakeholders at all levels.
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Kupiszewski, Marek, Dušan Drbohlav, Philip Rees, and Helen Durham. "Internal Migration and Regional Population Dynamics - Czech Republic in the Context of European Trends." Geografie 104, no. 2 (1999): 89–105. http://dx.doi.org/10.37040/geografie1999104020089.
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This paper is a shortened version of the publication "Czech Case Study: Internal Migration and Regional Population Dynamics in Europe" that originated as part of a comparative research carried out in ten European countries under the umbrella of the Council of Europe in between 1995 and 1998. It concentrates on analysis of internal migration movements (by Czech districts in 1984 and 1994/1995) and on the migratory behaviour by different age groups (in different life course stages). Furthermore, the paper is focused on the relationships between migration on one side and the following independent variables on the other side: urbanisation rate, population density, functional classification, and unemployment.