Changing numbers of three gull species in the British Isles

Between-population variation of changes in numbers can provide insights into factors influencing variation in demography and how population size or density is regulated. Here, we describe spatio-temporal patterns of population change of Herring Gull (Larus argentatus), Lesser Black-backed Gull (L. fuscus) and Great Black-backed Gull (L. marinus) in the British Isles from national censuses and survey data. The aim of this study was to test for density-dependence and spatial variation in population trends as two possible, but not mutually exclusive, explanations of population changes with important implications for the understanding of these changes. Between 1969 and 2013 the three species showed different population trends with Herring Gulls showing a strong decline, Great Black-backed Gulls a less pronounced decline and Lesser Black-backed Gulls an increase until 2000 but then a decline since. Population changes also varied between different regions of the British Isles, with the Atlantic coast showing declines and the North Sea coast increases in all three species. Population changes were density-dependent in the Herring Gull, and Lesser Black-backed Gulls showed faster population increases at lower Herring Gull densities. Contrasting numbers of gulls nest in coastal habitats or on roofs (mainly in urban habitats). Herring Gulls seem to seek refuge in urban environments, whereas Lesser Black-backed Gulls expand their range into the urban environment. The large declines in hitherto abundant species create a dilemma for conservation bodies in prioritizing conservation policies. The spatial variation in population changes and the differences between species suggest that there is no single cause for the observed changes, thus requiring region-specific conservation management strategies

Increased use of intertidal resources benefits breeding success in a generalist gull species

Determining how resource use impacts on a species’ demography is important, especially in habitats which are being altered by anthropogenic land-use change. If changes result in species consuming resources of reduced quality their demographic traits may be adversely affected. Generalist species are useful when investigating changes in resource availability as they can switch to alternatives if their preferred food becomes unavailable. For species that can forage on marine and terrestrial resources, it is often not known whether a switch from marine to terrestrial resources will have negative consequences. The herring gull, Larus argentatus, is one widespread generalist that opportunistically forages within marine and terrestrial habitats that are increasingly altered by humans. We determined marine and terrestrial resource use of gulls from eight colonies over two years across south-west Scotland and Northern Ireland using pellets and stable isotope analysis of chick feathers, which gave comparable results. Herring gulls in the study region used very little marine offshore resources but birds from colonies located in areas with sheltered coastlines, which provide abundant and diverse marine food from the intertidal zone, foraged more on marine intertidal resources. In contrast, colonies closer to built-up areas used more terrestrial resources. Herring gulls raised larger broods in colonies where they consumed a higher proportion of marine resource. Therefore, where generalist species, such as gulls, switch to an alternative resources that is available to them within their foraging range this may come at a cost of lower breeding success

A cross-sectional study of retired Great British Olympians (Berlin 1936 - Sochi 2014):Olympic career injuries, joint health in later life, and reasons for retirement from Olympic sport

The relationship between Olympic career sport injury and the long-term musculoskeletal health of the elite athlete remains unclear. This study describes the lifetime prevalence of medical attention injuries that occurred during training and/or competition as part of the athlete’s Olympic career, reasons for retirement from Olympic sport, and the point prevalence of pain and osteoarthritis (OA) among retired Great Britain’s (GB) Olympians

BDNF Val66Met polymorphism in patterns of neural activation in individuals with MDD and healthy controls.

BACKGROUND: Rs6265 single nucleotide polymorphism, which influences brain-derived neurotrophic factor (BDNF) levels in the cortical and subcortical brain structures, may result in distinguished patterns of neural activation during a major depressive disorder (MDD) episode. Valine homozygotes with high levels of BDNF and methionine carriers with lower levels of BDNF may present specific neural correlates of MDD. In our study we have tested differences in blood oxygen level dependant (BOLD) signal between individuals with MDD and healthy controls for both allelic variants. METHODS: Individuals with MDD (N = 37) and healthy controls (N = 39) were genotyped for rs6265 and compared separately in each allelic variant for BOLD response in a functional magnetic resonance imaging experiment examining appraisal of emotional scenes. The two allelic variants were also compared separately for both individuals with MDD and healthy controls. RESULTS: In the homozygous valine group MDD was associated with decreased neural activation in areas responsible for cognitive appraisal of emotional scenes. In the methionine group MDD was related to increased activation in subcortical regions responsible for visceral reaction to emotional stimuli. During an MDD episode methionine carriers showed more activation in areas associated with cognitive appraisal of emotional information in comparison to valine homozygotes. LIMITATIONS: Small sample size of healthy controls carrying methionine (N=8). CONCLUSION: Our results suggest that allelic variations in the rs6265 gene lead to specific neural correlates of MDD which may be associated with different mechanisms of MDD in the two allelic groups. This may have potential importance for screening and treatment of patients.Funding for this study was provided by the Science Foundation Ireland (Grant Number: SFI/07SK/B1214C). Health Research Board (HRB) Ireland provided funding for magnetic resonance imaging infrastructure at the Centre of Advanced Medical Imaging (CAMI) at St. James’s Hospital in Dublin.This is the author accepted manuscript. The final version is available from Elsevier at http://www.jad-journal.com/article/S0165-0327%2815%2900383-3/abstract