scholarly journals The influence of morphological variation on migration performance in a trans-hemispheric migratory songbird

2015 ◽  
Vol 2 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Lawrence Lam ◽  
Emily A. McKinnon ◽  
James D. Ray ◽  
Myrna Pearman ◽  
Glen T. Hvenegaard ◽  
...  
Keyword(s):  
Body Size ◽  
Morphological Traits ◽  
Light Level ◽  
Spring Migration ◽  
Future Research ◽  
Long Distance ◽  
Intrinsic Factors ◽  
Migratory Songbirds ◽  
Migratory Songbird ◽  
Direct Tracking

AbstractFor long-distance migratory songbirds, morphological traits such as longer wings and a smaller body size are predicted to increase migration efficiency. Due to previous limitations in our ability to track the long-distance journeys of small-bodied birds, the relationship between morphology and start-to-finish migration performance has never been fully tested in free-living songbirds. Using direct-tracking data obtained from light-level geolocators, we examined the effects of morphological factors (wing and body size) on spring and fall migration performance (flight speed, duration of stopovers, total stopovers taken) of a widely distributed, trans-hemispheric migratory songbird, the purple martin (Progne subis) (n = 120). We found that smaller-bodied birds spent fewer days at stopovers along fall migration, but larger-bodied birds spent fewer days at stopover and took fewer stopovers during spring migration. More of the variation in fall migration performance was explained by morphology, as compared to spring migration, possibly indicating a larger influence of environmental conditions on spring performance. Overall, our results partially support long-standing and previously untested predictions regarding the influence of intrinsic factors on migration performance. Future research should examine the influence of environmental variation on migration performance as well as additional morphological traits that may contribute to migration performance.

scholarly journals Habitat loss on the breeding grounds is a major contributor to population declines in a long-distance migratory songbird

2021 ◽  
Vol 288 (1949) ◽  
Author(s):  
Michael T. Hallworth ◽  
Erin Bayne ◽  
Emily McKinnon ◽  
Oliver Love ◽  
Junior A. Tremblay ◽  
...  
Keyword(s):  
Habitat Loss ◽  
Annual Cycle ◽  
Forest Loss ◽  
Population Declines ◽  
Migration Routes ◽  
Long Distance ◽  
Migratory Songbirds ◽  
Breeding Grounds ◽  
Migratory Songbird ◽  
Land Use Practices

Many migratory species are declining and for most, the proximate causes of their declines remain unknown. For many long-distance Neotropical migratory songbirds, it is assumed that habitat loss on breeding or non-breeding grounds is a primary driver of population declines. We integrated data collected from tracking technology, community science and remote sensing data to quantify migratory connectivity (MC), population trends and habitat loss. We quantified the correlation between forest change throughout the annual cycle and population declines of a long-distance migratory songbird, the Connecticut warbler ( Oporornis agilis , observed decline: −8.99% yr −1 ). MC, the geographic link between populations during two or more phases of the annual cycle, was stronger between breeding and autumn migration routes (MC = 0.24 ± 0.23) than between breeding and non-breeding locations (MC = −0.2 ± 0.14). Different Connecticut warbler populations tended to have population-specific fall migration routes but overlapped almost completely within the northern Gran Chaco ecoregion in South America. Cumulative forest loss within 50 km of breeding locations and the resulting decline in the largest forested patch index was correlated more strongly with population declines than forest loss on migratory stopover regions or on wintering locations in South America, suggesting that habitat loss during the breeding season is a driver of observed population declines for the Connecticut warbler. Land-use practices that retain large, forested patches within landscapes will likely benefit breeding populations of this declining songbird, but further research is needed to help inform land-use practices across the full annual cycle to minimize the impacts to migratory songbirds and abate ongoing population declines.

scholarly journals The annual cycle of a trans-equatorial Eurasian–African passerine migrant: different spatio-temporal strategies for autumn and spring migration

2011 ◽  
Vol 279 (1730) ◽  
pp. 1008-1016 ◽  
Author(s):  
Anders P. Tøttrup ◽  
Raymond H. G. Klaassen ◽  
Roine Strandberg ◽  
Kasper Thorup ◽  
Mikkel Willemoes Kristensen ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Arabian Peninsula ◽  
Light Level ◽  
Spring Migration ◽  
Control Mechanisms ◽  
Long Distance ◽  
Breeding Sites ◽  
Lanius Collurio ◽  
Breeding Grounds ◽  
Spatio Temporal

The small size of the billions of migrating songbirds commuting between temperate breeding sites and the tropics has long prevented the study of the largest part of their annual cycle outside the breeding grounds. Using light-level loggers (geolocators), we recorded the entire annual migratory cycle of the red-backed shrike Lanius collurio , a trans-equatorial Eurasian-African passerine migrant. We tested differences between autumn and spring migration for nine individuals. Duration of migration between breeding and winter sites was significantly longer in autumn (average 96 days) when compared with spring (63 days). This difference was explained by much longer staging periods during autumn (71 days) than spring (9 days). Between staging periods, the birds travelled faster during autumn (356 km d –1 ) than during spring (233 km d –1 ). All birds made a protracted stop (53 days) in Sahelian sub-Sahara on southbound migration. The birds performed a distinct loop migration (22 000 km) where spring distance, including a detour across the Arabian Peninsula, exceeded the autumn distance by 22 per cent. Geographical scatter between routes was particularly narrow in spring, with navigational convergence towards the crossing point from Africa to the Arabian Peninsula. Temporal variation between individuals was relatively constant, while different individuals tended to be consistently early or late at different departure/arrival occasions during the annual cycle. These results demonstrate the existence of fundamentally different spatio-temporal migration strategies used by the birds during autumn and spring migration, and that songbirds may rely on distinct staging areas for completion of their annual cycle, suggesting more sophisticated endogenous control mechanisms than merely clock-and-compass guidance among terrestrial solitary migrants. After a century with metal-ringing, year-round tracking of long-distance migratory songbirds promises further insights into bird migration.

scholarly journals Ontogeny of body size and shape of Antarctic and subantarctic fur seals

2007 ◽  
Vol 85 (12) ◽  
pp. 1275-1285 ◽  
Author(s):  
Sebastián P. Luque ◽  
Edward H. Miller ◽  
John P.Y. Arnould ◽  
Magaly Chambellant ◽  
Christophe Guinet
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Morphological Traits ◽  
Body Shape ◽  
Size And Shape ◽  
Fur Seals ◽  
Fur Seal ◽  
Adult Body ◽  
Weaning Age ◽  
Lactation Duration

Pre- and post-weaning functional demands on body size and shape of mammals are often in conflict, especially in species where weaning involves a change of habitat. Compared with long lactations, brief lactations are expected to be associated with fast rates of development and attainment of adult traits. We describe allometry and growth for several morphological traits in two closely related fur seal species with large differences in lactation duration at a sympatric site. Longitudinal data were collected from Antarctic ( Arctocephalus gazella (Peters, 1875); 120 d lactation) and subantarctic ( Arctocephalus tropicalis (Gray, 1872); 300 d lactation) fur seals. Body mass was similar in neonates of both species, but A. gazella neonates were longer, less voluminous, and had larger foreflippers. The species were similar in rate of preweaning growth in body mass, but growth rates of linear variables were faster for A. gazella pups. Consequently, neonatal differences in body shape increased over lactation, and A. gazella pups approached adult body shape faster than did A. tropicalis pups. Our results indicate that preweaning growth is associated with significant changes in body shape, involving the acquisition of a longer, more slender body with larger foreflippers in A. gazella. These differences suggest that A. gazella pups are physically more mature at approximately 100 d of age (close to weaning age) than A. tropicalis pups of the same age.

Archaic Origins of the Lowland Maya

2010 ◽  
Vol 21 (3) ◽  
pp. 312-352 ◽  
Author(s):  
Jon C. Lohse
Keyword(s):  
Cultural Change ◽  
New Technologies ◽  
Cultural Practices ◽  
Future Research ◽  
Late Archaic ◽  
Long Distance ◽  
Radiocarbon Data ◽  
Cultural Origins ◽  
Lines Of Evidence ◽  
Lowland Maya

The earliest Lowland Maya are commonly recognized by permanent architecture and the appearance of pottery. However, when other lines of evidence are considered, strong continuities with late Archaic populations can be seen. Reconciling these views relies on more than simply gathering more data. It is also necessary to consider the effect of decades of scholarship that defines the precolumbian Maya as “civilization” rather than considering the historical contexts of important transitions, such as the one that culminated with sedentism, the adoption of new technologies, and participation in long-distance exchange. The Archaic-to-Preclassic transition was relatively brief and largely obscured by the practices of establishing permanent dwellings. Nevertheless, this period must have been extremely dynamic and marked by significant cultural change, making it important to researchers interested in early Mesoamerica. Using three lines of evidence—subsistence, economy and technology, and stratigraphically controlled radiocarbon data—this article argues that the Lowland Maya had their cultural origins at least in the late Archaic and that the case for pottery before ca. 1000 B.C. remains uncertain. Future research is needed to determine precisely how far back in time certain cultural practices that characterize Preclassic and Classic Maya society can be documented.

scholarly journals The movement ecology of seagrasses

2014 ◽  
Vol 281 (1795) ◽  
pp. 20140878 ◽  
Author(s):  
Kathryn McMahon ◽  
Kor-jent van Dijk ◽  
Leonardo Ruiz-Montoya ◽  
Gary A. Kendrick ◽  
Siegfried L. Krauss ◽  
...  
Keyword(s):  
Life History ◽  
Clonal Growth ◽  
Movement Ecology ◽  
Future Research ◽  
The Novel ◽  
Long Distance ◽  
Spatial And Temporal Scales ◽  
Life History Stages ◽  
Research Areas ◽  
Time Movement

A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.

Range‐wide populations of a long‐distance migratory songbird converge during stopover in the tropics

2019 ◽  
Vol 89 (2) ◽  
pp. e01349 ◽  
Author(s):  
Camila Gómez ◽  
Sara L. Guerrero ◽  
Alyssa M. FitzGerald ◽  
Nicholas J. Bayly ◽  
Keith A. Hobson ◽  
...  
Keyword(s):  
Long Distance ◽  
Migratory Songbird ◽  
The Tropics

scholarly journals Birds facing climate change: a qualitative model for the adaptive potential of migratory behaviour

2015 ◽  
Vol 85 (1) ◽  
pp. 3 ◽  
Author(s):  
Michelangelo Morganti
Keyword(s):  
Climate Change ◽  
Phenotypic Plasticity ◽  
Migratory Birds ◽  
Future Research ◽  
Qualitative Model ◽  
Migratory Behaviour ◽  
Adaptive Potential ◽  
Long Distance ◽  
Genetic Determination ◽  
Recent Climate

Recent climate change is altering the migratory behaviour of many bird species. An advancement in the timing of spring events and a shift in the geographical distribution have been detected for birds around the world. In particular, intra-Palearctic migratory birds have advanced arrivals in spring and shortened migratory distances by shifting northward their wintering grounds. These changes in migratory patterns are considered adaptive responses facilitating the adjustment of the life cycle to the phenological changes found in their breeding areas. However, in some cases, populations exposed to the same selective pressures do not show any appreciable adaptive change in their behaviour. Basing on the comparison of realized and non-realized adaptive changes, I propose here the formulation of a qualitative model that predicts the potential of migratory birds populations to change adaptively their migratory behaviour. The model assumes that the adaptive potential of migratory behaviour is fuelled by both genetic diversity and phenotypic plasticity. Populations of long-distance migrants are exposed to strong environmental canalization that largely eroded their phenotypic plasticity and reduced genetic variability, so that they show a very low amount of adaptive potential regarding migratory behaviour. On the contrary, partial-migrant populations have a highly varied genetic profile and are more plastic at the phenotypic level, and consequently show the highest amount of adaptive potential. Species with mainly social and mainly genetic determination of the migratory behaviour are separately treated in the model. Specific empirical models to foresee the adaptive strategies of wild bird populations that face to climate change can be derived from the general theoretical model. As example, a specific model about the shortening of migratory distances in Western European migratory bird is presented. Finally, a number of future research lines on the topic of adaptive potential of migratory behaviour are discussed, including some examples of concrete study cases. In conclusion, partial-migration emerge as the less known system and future research efforts on this topic are expected to be especially fruitful.

scholarly journals Systematic Review and Meta-Analysis of Virtual Reality in Mental Healthcare: Effects of Full Body Illusions on Body Image Disturbance

2021 ◽  
Vol 2 ◽  
Author(s):  
Collin Turbyne ◽  
Abe Goedhart ◽  
Pelle de Koning ◽  
Frederike Schirmbeck ◽  
Damiaan Denys
Keyword(s):  
Body Image ◽  
Virtual Reality ◽  
Body Size ◽  
Clinical Utility ◽  
Meta Analysis ◽  
Future Research ◽  
Head Mounted Display ◽  
Full Body ◽  
Virtual Body ◽  
Clinical Populations

Background: Body image (BI) disturbances have been identified in both clinical and non-clinical populations. Virtual reality (VR) has recently been used as a tool for modulating BI disturbances through the use of eliciting a full body illusion (FBI). This meta-analysis is the first to collate evidence on the effectiveness of an FBI to reduce BI disturbances in both clinical and non-clinical populations.Methods: We performed a literature search in MEDLINE (PubMed), EMBASE, PsychINFO, and Web of Science with the keywords and synonyms for “virtual reality” and “body image” to identify published studies until September 2020. We included studies that (1) created an FBI with a modified body shape or size and (2) reported BI disturbance outcomes both before and directly after the FBI. FBI was defined as a head-mounted display (HMD)-based simulation of embodying a virtual body from an egocentric perspective in an immersive 3D computer-generated environment.Results: Of the 398 identified unique studies, 13 were included after reading full-texts. Four of these studies were eligible for a meta-analysis on BI distortion inducing a small virtual body FBI in healthy females. Significant post-intervention results were found for estimations of shoulder width, hip width, and abdomen width, with the largest reductions in size being the estimation of shoulder circumference (SMD = −1.3; 95% CI: −2.2 to −0.4; p = 0.004) and hip circumference (SMD = −1.0; 95% CI: −1.6 to −0.4; p = 0.004). Mixed results were found in non-aggregated studies from large virtual body FBIs in terms of both estimated body size and BI dissatisfaction and in small virtual body FBI in terms of BI dissatisfaction.Conclusions: The findings presented in this paper suggest that the participants' BIs were able to conform to both an increased as well as a reduced virtual body size. However, because of the paucity of research in this field, the extent of the clinical utility of FBIs still remains unclear. In light of these limitations, we provide implications for future research about the clinical utility of FBIs for modulating BI-related outcomes.

scholarly journals RNA Motifs and Modification Involve in RNA Long-Distance Transport in Plants

2021 ◽  
Vol 9 ◽  
Author(s):  
Tao Wang ◽  
Xiaojun Li ◽  
Xiaojing Zhang ◽  
Qing Wang ◽  
Wenqian Liu ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Future Research ◽  
Rna Transport ◽  
Long Distance ◽  
Rna Motifs ◽  
Related Sequence ◽  
Long Distance Transport ◽  
Nucleotide Mutation ◽  
Distance Transport

A large number of RNA molecules have been found in the phloem of higher plants, and they can be transported to distant organelles through the phloem. RNA signals are important cues to be evolving in fortification strategies by long-distance transportation when suffering from various physiological challenges. So far, the mechanism of RNA selectively transportation through phloem cells is still in progress. Up to now, evidence have shown that several RNA motifs including Polypyrimidine (poly-CU) sequence, transfer RNA (tRNA)-related sequence, Single Nucleotide Mutation bound with specific RNA binding proteins to form Ribonucleotide protein (RNP) complexes could facilitate RNA mobility in plants. Furthermore, some RNA secondary structure such as tRNA-like structure (TLS), untranslation region (UTR) of mRNA, stem-loop structure of pre-miRNA also contributed to the mobility of RNAs. Latest researchs found that RNA methylation such as methylated 5′ cytosine (m5C) played an important role in RNA transport and function. These studies lay a theoretical foundation to uncover the mechanism of RNA transport. We aim to provide ideas and clues to inspire future research on the function of RNA motifs in RNA long-distance transport, furthermore to explore the underlying mechanism of RNA systematic signaling.

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