Search results for "Charadriiformes"
showing 10 items of 20 documents
Demographic responses of a site-faithful and territorial predator to its fluctuating prey: long-tailed skuas and arctic lemmings.
2014
Summary1. Environmental variability, through interannual variation in food availability or climaticvariables, is usually detrimental to population growth. It can even select for constancy in keylife-history traits, though some exceptions are known. Changes in the level of environmentalvariability are therefore important to predict population growth or life-history evolution.Recently, several cyclic vole and lemming populations have shown large dynamical changesthat might affect the demography or life-histories of rodent predators.2. Skuas constitute an important case study among rodent predators, because of theirstrongly saturating breeding productivity (they lay only two eggs) and high deg…
Analysis of trematode parasite communities in fish eye lenses by pyrosequencing of naturally pooled DNA.
2011
Infections by multiple parasite species are common in nature and have important consequences for between species interactions and coevolutionary dynamics with the host populations. For example ecological and evolutionary factors underlying the structure of parasite communities determine the range of hosts a parasite can infect and set the basis for both evolution of host defences and parasite virulence as well as management of diseases. Studies investigating these factors have been facilitated in the recent past by genetic methods which surmount difficulties of traditional morphological taxonomy in identifying individual parasite species. Here we take a step further and present a novel meth…
Guano-Derived Nutrient Subsidies Drive Food Web Structure in Coastal Ponds.
2016
A stable isotope study was carried out seasonally in three coastal ponds (Marinello system, Italy) affected by different gull guano input to investigate the effect of nutrient subsidies on food web structure and dynamics. A marked 15N enrichment occurred in the pond receiving the highest guano input, indicating that gull-derived fertilization (guanotrophication) had a strong localised effect and flowed across trophic levels. The main food web response to guanotrophication was an overall erosion of the benthic pathway in favour of the planktonic. Subsidized primary consumers, mostly deposit feeders, switched their diet according to organic matter source availability. Secondary consumers and,…
Living on the edge of a shrinking habitat: the ivory gull, Pagophila eburnea, an endangered sea-ice specialist.
2016
International audience; The ongoing decline of sea ice threatens many Arctic taxa, including the ivory gull. Understanding how ice-edges and ice concentrations influence the distribution of the endangered ivory gulls is a prerequisite to the implementation of adequate conservation strategies. From 2007 to 2013, we used satellite transmitters to monitor the movements of 104 ivory gulls originating from Canada, Greenland, Svalbard-Norway and Russia. Although half of the positions were within 41 km of the ice-edge (75% within 100 km), approximately 80% were on relatively highly concentrated sea ice. Ivory gulls used more concentrated sea ice in summer, when close to their high-Arctic breeding …
Comparative host–parasite population structures: disentangling prospecting and dispersal in the black-legged kittiwake Rissa tridactyla
2005
Although much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black-legged kittiwake ( Rissa tridactyla ) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species’ range and, at the same time, collected individuals of one of its common ectoparasites, the tick Ixodes uriae . Parasites were …
Unexpected diversity in socially synchronized rhythms of shorebirds.
2016
The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1,2,3,4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1,5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6,7,8,9,10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6,7,8,9,11. The behavioural rhythms that em…
Susceptibility of eye fluke-infected fish to predation by bird hosts.
2005
Host manipulation by trophically transmitted parasites may predispose infected hosts to predation and in this way enhance parasite transmission. In most study systems, however, the evidence comes from laboratory studies, and therefore knowledge of the effect of manipulation on parasite transmission efficiency in the wild is still limited. Here we examined the effect ofDiplostomum spathaceum(Trematoda) eye flukes on the susceptibility of fish intermediate hosts to predation by bird definitive hosts. Our earlier studies have shown that the parasite alters fish phenotype and increases their susceptibility to artificial predation under laboratory conditions. In the present field study, we allow…
Variable exposure and immunological response to Lyme disease Borrelia among North Atlantic seabird species.
2008
Colonial seabirds often breed in large aggregations. These individuals can be exposed to parasitism by the tick Ixodes uriae , but little is known about the circulation of pathogens carried by this ectoparasite, including Lyme disease Borrelia . Here we investigated the prevalence of antibodies (Ab) against Borrelia burgdorferi sensu lato in seabird species sampled at eight locations across the North Atlantic. Using enzyme-linked immunosorbent assay tests, we found that the prevalence of anti- Borrelia Ab in adult seabirds was 39.6% on average (over 444 individuals), but that it varied among colonies and species. Common guillemots showed higher seroprevalence (77.1%±5.9) than black-legged …
Status, distribution and conservation of Kentish plover <em>Charadrius alexandrinus</em> (Aves, Charadriiformes) in Sicily
2021
The Kentish Plover Charadrius alexandrinus is a sensitive species whose national breeding population has been undergoing a sharp decrease, up to 50%, in 2010 compared to the previous decade. Due to the lack of updated data and fragmented knowledge about its current status and distribution in Sicily, a specific and accurate monitoring of this species was carried out during the years 2018 and 2019. About 230 km of coastline and 64 UTM squares 10x10 km were investigated during the breeding seasons, and a total of 205-287 pairs have been estimated for the whole region, distributed in 41 UTM squares (including the island of Favignana). Pairs are mainly concentrated in the complex of “Saline di T…
Behavioural responses of breeding arctic sandpipers to ground-surface temperature and primary productivity
2021
Most birds incubate their eggs, which requires time and energy at the expense of other activities. Birds generally have two incubation strategies: biparental where both mates cooperate in incubating eggs, and uniparental where a single parent incubates. In harsh and unpredictable environments, incubation is challenging due to high energetic demands and variable resource availability. We studied the relationships between the incubation behaviour of sandpipers (genus Calidris) and two environmental variables: temperature and a proxy of primary productivity (i.e. NDVI). We investigated how these relationships vary between incubation strategies and across species among strategies. We also stud…