Convergence of broad-scale migration strategies in terrestrial birds

Migration is a common strategy used by birds that breed in seasonal environments. Selection for greater migration efficiency is likely to be stronger for terrestrial species whose migration strategies require non-stop transoceanic crossings. If multiple species use the same transoceanic flyway, then we expect the migration strategies of these species to converge geographically towards the most optimal solution. We test this by examining population-level migration trajectories within the Western Hemisphere for 118 migratory species using occurrence information from eBird. Geographical convergence of migration strategies was evident within specific terrestrial regions where geomorphological features such as mountains or isthmuses constrained overland migration. Convergence was also evident for transoceanic migrants that crossed the Gulf of Mexico or Atlantic Ocean. Here, annual population-level movements were characterized by clockwise looped trajectories, which resulted in faster but more circuitous journeys in the spring and more direct journeys in the autumn. These findings suggest that the unique constraints and requirements associated with transoceanic migration have promoted the spatial convergence of migration strategies. The combination of seasonal atmospheric and environmental conditions that has facilitated the use of similar broad-scale migration strategies may be especially prone to disruption under climate and land-use change.

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Retinopathy of Prematurity: A New Epidemic?

PEDIATRICS ◽

10.1542/peds.83.4.486 ◽

1989 ◽

Vol 83 (4) ◽

pp. 486-492

Author(s):

Donna L. Gibson ◽

Samuel B. Sheps ◽

Martin T. Schechter ◽

Sandra Wiggins ◽

Andrew Q. McCormick

Keyword(s):

British Columbia ◽

Birth Weight ◽

Retinopathy Of Prematurity ◽

Population Level ◽

Population Based ◽

Standardized Incidence Ratio ◽

Canadian Province ◽

Annual Population ◽

Diagnostic Changes ◽

Increases In Risk

This study provides the first empiric evidence for the existence of a new epidemic of retinopathy of prematurity-induced blindness. Data from a population-based register of handicapping conditions in the Canadian province of British Columbia, and a birth weight-specific census of live-born infants in British Columbia, were used to determine annual, population-level incidences of retinopathy of prematurity-induced blindness during 1952 to 1983. Changes in incidence since the end of the original epidemic (1954) were determined by subdividing the 29-year period (1955 to 1983) into two intervals (1955 to 1964 and 1965 to 1983). Standardized incidence ratio analyses revealed a marginally significant increase in the overall incidence of retinopathy of prematurity-induced blindness in the later as compared with the earlier period. Infants weighing 750 to 999 g at birth had a significantly increased standardized incidence ratio of 3.07 (95% confidence interval 1.26, 11.06). No increases in risk were observed in heavier or lighter weight infants. Because ascertainment and diagnostic changes do not explain the weight-specific increases in incidence, these results provide the first population-level evidence for a new epidemic.

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Aridity weakens population-level effects of multiple species interactions on Hibiscus meyeri

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1708436115 ◽

2017 ◽

Vol 115 (3) ◽

pp. 543-548 ◽

Cited By ~ 13

Author(s):

Allison M. Louthan ◽

Robert M. Pringle ◽

Jacob R. Goheen ◽

Todd M. Palmer ◽

William F. Morris ◽

...

Keyword(s):

Population Growth ◽

Species Interactions ◽

Abiotic Factors ◽

Population Level ◽

Distinct Species ◽

High Elevation ◽

Relative Strength ◽

Herbaceous Plant ◽

Species Abundances ◽

Multiple Species

Predicting how species’ abundances and ranges will shift in response to climate change requires a mechanistic understanding of how multiple factors interact to limit population growth. Both abiotic stress and species interactions can limit populations and potentially set range boundaries, but we have a poor understanding of when and where each is most critical. A commonly cited hypothesis, first proposed by Darwin, posits that abiotic factors (e.g., temperature, precipitation) are stronger determinants of range boundaries in apparently abiotically stressful areas (“stress” indicates abiotic factors that reduce population growth), including desert, polar, or high-elevation environments, whereas species interactions (e.g., herbivory, competition) play a stronger role in apparently less stressful environments. We tested a core tenet of this hypothesis—that population growth rate is more strongly affected by species interactions in less stressful areas—using experimental manipulations of species interactions affecting a common herbaceous plant, Hibiscus meyeri (Malvaceae), across an aridity gradient in a semiarid African savanna. Population growth was more strongly affected by four distinct species interactions (competition with herbaceous and shrubby neighbors, herbivory, and pollination) in less stressful mesic areas than in more stressful arid sites. However, contrary to common assumptions, this effect did not arise because of greater density or diversity of interacting species in less stressful areas, but rather because aridity reduced sensitivity of population growth to these interactions. Our work supports classic predictions about the relative strength of factors regulating population growth across stress gradients, but suggests that this pattern results from a previously unappreciated mechanism that may apply to many species worldwide.

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Changes in migration phenology and biometrical traits of Reed, Marsh and Sedge Warblers

Open Life Sciences ◽

10.2478/s11535-011-0101-1 ◽

2012 ◽

Vol 7 (1) ◽

pp. 115-125 ◽

Cited By ~ 5

Author(s):

Szilvia Kovács ◽

Péter Fehérvári ◽

Krisztina Nagy ◽

Andrea Harnos ◽

Tibor Csörgő

Keyword(s):

Body Mass ◽

Population Level ◽

Long Distance ◽

Stopover Site ◽

Sedge Warbler ◽

Global Environmental ◽

Migration Phenology ◽

Spring Arrival ◽

Migration Strategies ◽

Migrant Birds

AbstractGlobal environmental processes like climate change could severely affect population level migratory behaviour of long range migrant birds. We analyzed changes in migration phenology and biometrics of three closely-related long-distance migrant Acrocephalus species. We used the records of 12 063 Sedge, 12 913 Reed, and 5 409 Marsh Warblers caught and ringed between 1989–2009, at a Hungarian stopover site. Quantile regressions were used to analyse the changes in spring and autumn migration phenology. Median spring arrival date of Sedge and Reed Warblers shifted 6.5 and 7.5 days earlier, respectively. Autumn arrival of all species shifted one (Reed and Marsh Warblers) or two (Sedge Warbler) weeks later. Mean body mass of adult Reed and Marsh Warblers decreased in spring (by 0.3 and 0.2 grams, respectively) and in autumn (by 0.8 and 0.2 grams, respectively) while body mass of adult Sedge Warblers decreased only in autumn (by 0.4 grams). Mean wing length of all species increased significantly (range of change: 0.6–1 mm). Despite the fact that the studied species are closely related, all three have remarkably different migration strategies. However, similar patterns can be observed in the studied parameters, indicating that global processes may have general effects on these species, albeit through markedly different mechanisms.

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Maximizing a new quantity in sequential reserve selection

Environmental Conservation ◽

10.1017/s0376892913000544 ◽

2013 ◽

Vol 41 (2) ◽

pp. 198-205 ◽

Cited By ~ 1

Author(s):

ADAM W. SCHAPAUGH ◽

ANDREW J. TYRE

Keyword(s):

Empirical Studies ◽

Optimal Solution ◽

Reserve Selection ◽

Stochastic Dynamic ◽

Site Assessment ◽

Reserve Network ◽

Fundamental Goal ◽

Markov Decision ◽

Dynamic Optimization Model ◽

Multiple Species

SUMMARYThe fundamental goal of conservation planning is biodiversity persistence, yet most reserve selection methods prioritize sites using occurrence data. Numerous empirical studies support the notion that defining and measuring objectives in terms of species richness (where the value of a site is equal to the number of species it contains, or contributes to an existing reserve network) can be inadequate for maintaining biodiversity in the long-term. An existing site-assessment framework that implicitly maximized the persistence probability of multiple species was integrated with a dynamic optimization model. The problem of sequential reserve selection as a Markov decision process was combined with stochastic dynamic programming to find the optimal solution. The approach represents a compromise between representation-based approaches (maximizing occurrences) and more complex tools, like spatially-explicit population models. The method, the inherent problems and interesting conclusions are illustrated with a land acquisition case study on the central Platte River.

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Population-level effects of immunocontraception in white-tailed deer (Odocoileus virginianus)

Wildlife Research ◽

10.1071/wr07128 ◽

2008 ◽

Vol 35 (6) ◽

pp. 494 ◽

Cited By ~ 29

Author(s):

Allen T. Rutberg ◽

Ricky E. Naugle

Keyword(s):

New York ◽

Odocoileus Virginianus ◽

Population Change ◽

Population Level ◽

Management Tool ◽

Strongly Correlated ◽

Management Tools ◽

Annual Population ◽

Population Effects

In North America, dense populations of white-tailed deer (Odocoileus virginianus) in suburbs, cities and towns have stimulated a search for new population-management tools. Most research on deer contraception has focused on the safety and efficacy of immunocontraceptive vaccines, but few studies have examined population-level effects. We report here results from two long-term studies of population effects of the porcine zona pellucida (PZP) immunocontraceptive vaccine, at the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, USA, and at Fire Island National Seashore (FIIS), New York, USA. Annual population change at NIST was strongly correlated with population fertility (rP = 0.82, P = 0.001); when population fertility at NIST dropped below 0.40 fawns per female, the population declined. Contraceptive treatments at NIST were associated with a 27% decline in population between 1997 and 2002, and fluctuated thereafter with the effectiveness of contraceptive treatments. In the most intensively treated segment of FIIS, deer population density declined by ~58% between 1997 and 2006. These studies demonstrate that, in principle, contraception can significantly reduce population size. Its usefulness as a management tool will depend on vaccine effectiveness, accessibility of deer for treatment, and site-specific birth, death, immigration, and emigration rates.

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Estimating the movements of terrestrial animal populations using broad-scale occurrence data

Movement Ecology ◽

10.1186/s40462-021-00294-2 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Sarah R. Supp ◽

Gil Bohrer ◽

John Fieberg ◽

Frank A. La Sorte

Keyword(s):

Population Level ◽

Sampling Bias ◽

Population Movements ◽

Spatial And Temporal Scales ◽

Temporal Sampling ◽

Multiple Observations ◽

Occurrence Data ◽

Population Distributions ◽

Animal Populations ◽

Broad Scale

AbstractAs human and automated sensor networks collect increasingly massive volumes of animal observations, new opportunities have arisen to use these data to infer or track species movements. Sources of broad scale occurrence datasets include crowdsourced databases, such as eBird and iNaturalist, weather surveillance radars, and passive automated sensors including acoustic monitoring units and camera trap networks. Such data resources represent static observations, typically at the species level, at a given location. Nonetheless, by combining multiple observations across many locations and times it is possible to infer spatially continuous population-level movements. Population-level movement characterizes the aggregated movement of individuals comprising a population, such as range contractions, expansions, climate tracking, or migration, that can result from physical, behavioral, or demographic processes. A desire to model population movements from such forms of occurrence data has led to an evolving field that has created new analytical and statistical approaches that can account for spatial and temporal sampling bias in the observations. The insights generated from the growth of population-level movement research can complement the insights from focal tracking studies, and elucidate mechanisms driving changes in population distributions at potentially larger spatial and temporal scales. This review will summarize current broad-scale occurrence datasets, discuss the latest approaches for utilizing them in population-level movement analyses, and highlight studies where such analyses have provided ecological insights. We outline the conceptual approaches and common methodological steps to infer movements from spatially distributed occurrence data that currently exist for terrestrial animals, though similar approaches may be applicable to plants, freshwater, or marine organisms.

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Variable individual consistency in timing and destination of winter migrating fish

Biology Letters ◽

10.1098/rsbl.2011.0634 ◽

2011 ◽

Vol 8 (1) ◽

pp. 21-23 ◽

Cited By ~ 30

Author(s):

Jakob Brodersen ◽

P. Anders Nilsson ◽

Ben B. Chapman ◽

Christian Skov ◽

Lars-Anders Hansson ◽

...

Keyword(s):

Population Level ◽

Differential Migration ◽

Migration Patterns ◽

Final Destination ◽

Individual Trait ◽

Timing Of Migration ◽

History Of ◽

Migration Strategies ◽

Individual Consistency ◽

Electronic Tags

Migration is an important event in the life history of many animals, but there is considerable variation within populations in the timing and final destination. Such differential migration at the population level can be strongly determined by individuals showing different consistencies in migratory traits. By tagging individual cyprinid fish with uniquely coded electronic tags, and recording their winter migrations from lakes to streams for 6 consecutive years, we obtained highly detailed long-term information on the differential migration patterns of individuals. We found that individual migrants showed consistent site fidelities for over-wintering streams over multiple migratory seasons and that they were also consistent in their seasonal timing of migration. Our data also suggest that consistency itself can be considered as an individual trait, with migrants that exhibit consistent site fidelity also showing consistency in migratory timing. The finding of a mixture of both consistent and inconsistent individuals within a population furthers our understanding of intrapopulation variability in migration strategies, and we hypothesize that environmental variation can maintain such different strategies.

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Systematic Review on International Salt Reduction Policy in Restaurants

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17249570 ◽

2020 ◽

Vol 17 (24) ◽

pp. 9570

Author(s):

Jingmin Ding ◽

Yuewen Sun ◽

Yuan Li ◽

Jing He ◽

Harriet Sinclair ◽

...

Keyword(s):

Salt Intake ◽

Early Stage ◽

Grey Literature ◽

Population Level ◽

Long Term Effects ◽

Menu Labeling ◽

Salt Reduction ◽

Reduction Strategies ◽

Scientific Papers ◽

Common Strategy

As the catering sector has increasingly contributed to population-level salt intake, many countries have begun developing salt-reduction strategies for restaurants. This paper aims to provide an overview of global salt reduction policies in restaurants. Scientific papers and website materials were systematically searched from Web of Science, Science Direct, and PubMed, as well as official websites of government departments and organizations. A total of 78 full-text papers and grey literature works were included. From 58 countries and regions, 62 independent policies were identified, 27 of which were mandatory (3 with fines). The most common strategy was menu labeling, which was a component of 40 policies. Target setting (n = 23) and reformulation (n = 13) of dishes were also widely implemented. Other salt-reduction strategies included education campaign, chef training, toolkits delivery, table salt removal, media campaign, and government assistance such as free nutrition analysis and toolkits distribution. Most policies focused on chain restaurants. Evaluations of these policies were limited and showed inconsistent results, and more time is needed to demonstrate the clear long-term effects. Attention has been paid to salt reduction in restaurants around the world but is still at its early stage. The feasibility and effectiveness of the strategies need to be further explored.

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Year-round spatial distribution and migration phenology of a rapidly declining trans-Saharan migrant—evidence of winter movements and breeding site fidelity in European turtle doves

Behavioral Ecology and Sociobiology ◽

10.1007/s00265-021-03082-5 ◽

2021 ◽

Vol 75 (11) ◽

Author(s):

Yvonne R. Schumm ◽

Benjamin Metzger ◽

Eric Neuling ◽

Martin Austad ◽

Nicholas Galea ◽

...

Keyword(s):

Site Fidelity ◽

Central And Eastern Europe ◽

Bird Species ◽

Environmental Parameters ◽

Breeding Site ◽

Migratory Bird ◽

Tracking Data ◽

Migratory Species ◽

Satellite Transmitters ◽

Migration Strategies

Abstract Populations of migratory bird species have suffered a sustained and severe decline for several decades. Contrary to non-migratory species, understanding the causal mechanisms proves difficult (for migratory bird species) as underlying processes may operate across broad geographic ranges and stages of the annual cycle. Therefore, the identification of migration routes, wintering grounds, and stopover sites is crucial for the development of relevant conservation strategies for declining migrant bird species. We still lack fundamental data of the non-breeding movements for many migratory species, such as European turtle doves Streptopelia turtur, a trans-Saharan migrant. For this species, knowledge of non-breeding movements is mainly based on ringing data that are limited by a low recovery rate in Africa, and tracking studies with a strong bias towards individuals breeding in France. We used Argos satellite transmitters to obtain detailed year-round tracks and provide new insights on migration strategies and winter quarters, of turtle doves breeding in Central and Eastern Europe. The tracking data along with analysis of land cover data confirm previously assumed use of multiple wintering sites and the use of a wide range of forest and agricultural landscapes at the breeding grounds. Tracking data in combination with environmental parameters demonstrated that most environmental parameters and niche breadth differed between breeding and wintering grounds. “Niche tracking” was only observed regarding night-time temperatures. Furthermore, we provide evidence for breeding site fidelity of adult individuals and for home range size to increase with an increasing proportion of agricultural used areas. Significance statement The European turtle dove, a Palearctic-African migrant species, is one of the fastest declining birds in Europe. The rapid decline is presumed to be caused mainly by habitat modification and agricultural changes. Here, we represent data on migration strategies, flyways, and behavior on European breeding and African non-breeding sites of turtle doves breeding in Central and Eastern Europe equipped with satellite transmitters. Our results confirm the use of different migration flyways and reveal an indication for “niche switching” behavior in terms of environmental factors during the different annual phases. The migratory behaviors revealed by the tracking approach, e.g., prolonged stopovers during autumn migration in Europe overlapping with time of hunting activities, stopovers in North Africa during spring migration, or evidence for loop migration, are important protection-relevant findings, particularly for the Central-Eastern flyway, for which no tracking data has been analyzed prior to our study.

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Seasonal and year-round use of the Ramsar-listed Kushiro Wetland by sika deer (Cervus nippon yesoensis)

10.7287/peerj.preprints.3048v1 ◽

2017 ◽

Author(s):

Hino Takafumi ◽

Tatsuya Kamii ◽

Takunari Murai ◽

Ryoto Yoshida ◽

Atsuki Sato ◽

...

Keyword(s):

Sika Deer ◽

Movement Patterns ◽

Cervus Nippon ◽

Population Level ◽

Seasonal Migration ◽

Home Ranges ◽

Seasonal Movement ◽

Annual Population ◽

The Impact ◽

Cervus Nippon Yesoensis

The sika deer (Cervus nippon yesoensis) population in the Ramsar-listed Kushiro Wetland has increased in recent years, and the Ministry of the Environment of Japan has decided to take measures to reduce the impact these sika deer are having on the ecosystem. However, their seasonal movement patterns, i.e., when and how the deer inhabit the wetland, remain unclear. Thus, we examined seasonal movement patterns and the population structure of sika deer in the Kushiro Wetland from 2013 to 2015 by analyzing GPS location data for 28 hinds captured at three sites in the wetland. Seasonal movement patterns were quantitatively classified as seasonal migration, dispersal, nomadic, resident, or atypical, and the degree of wetland utilization for each individual was estimated. The overlap areas of population-level home ranges among capture sites were calculated for both the entire year and for individual seasons. Our results showed that approximately one-third of the individuals moved into and out of the wetland during the year as either seasonal migrants or individuals with atypical movement. Some of the individuals migrated to farmland areas outside the wetland (the farthest being 64 km away). Half of the individuals inhabited the wetland all or most of the year, i.e., 81–100% of their annual home range was within the wetland area. The movement patterns of these deer were classified not only as resident but also as seasonal migration, dispersal, nomadic, and atypical. Even among individuals captured at the same site, various seasonal movement patterns were identified. Annual population-level home ranges showed little to no overlap, and seasonal population-level home ranges were completely segregated among capture sites. Individual deer used the wetland either seasonally or year-round, and some populations inhabiting the wetland had sub-populations with different seasonal movement patterns, which need to be considered to achieve more effective ecosystem management including deer management in the wetland.

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