Search results for "Biological dispersal"
showing 10 items of 326 documents
Flexibility in otherwise consistent non-breeding movements of a long-distance migratory seabird, the long-tailed skua
2017
Quantifying within- and between-individual variation in animal migration strategies is a first step towards our understanding of the ability of migrants to adjust to changes in the en - vironment. We studied consistency (or, conversely, flexibility) in movement patterns at large (>1000 km) to meso-scales (100−1000 km) during the non-breeding season of the long-tailed skua Stercorarius longicaudus, a long-distance migratory Arctic seabird, using light-based geolocation. We obtained 97 annual tracks of 38 individuals and quantified similarity between routes. Overall, tracks of the same individual were generally within about 200 to 300 km of their previous year’s route, and more similar than t…
Re-establishment of zooplankton communities in temporary ponds after autumn flooding: Does restoration age matter?
2012
Abstract In temporary ponds, reestablishment of zooplankton communities depends on recruitment from the egg bank, the arrival of dispersers from within the region, and on successful establishment of newly arrived species following interaction with local abiotic and biotic factors. When the ponds dry up, zooplankton species may survive as dormant eggs, and since not all eggs hatch in the next season, eggs will accumulate in the sediment over time, representing an archive of the pond's historical biodiversity. To study the effect of “restoration age” (the time since a water body was restored), we studied groups of ponds that were restored in different years (1998, 2003 and 2007). The restorat…
Age-dependent inbreeding risk and offspring fitness costs in female black grouse
2011
Dispersal is an important mechanism used to avoid inbreeding. However, dispersal may only be effective for part of an individual's lifespan since, post-dispersal individuals that breed over multiple reproductive events may risk mating with kin of the philopatric sex as they age. We tested this hypothesis in black grouse Tetrao tetrix , and show that yearling females never mated with close relatives whereas older females did. However, matings were not with direct kin suggesting that short-distance dispersal to sites containing kin and subsequent overlap of reproductive lifespans between males and females were causing this pattern. Chick mass was lower when kinship was high, suggesting impor…
Phylogeography of Ptychadena mascareniensis suggests transoceanic dispersal in a widespread African-Malagasy frog lineage
2004
Aim The Mascarene ridged frog, Ptychadena mascareniensis, is the only African amphibian species thought to occur on Madagascar and on the Seychelles and also Mascarene islands. We explored its phylogenetic relationships and intraspecific genetic differentiation to contribute to the understanding of transoceanic dispersal in amphibians. Methods Fragments of the mitochondrial 16S rRNA gene were sequenced from specimens collected over most of the distribution area of P. mascareniensis, including populations from Madagascar, Mascarenes and Seychelles. Results We identified five deeply divergent clades having pairwise divergences >5%, which probably all represent cryptic species in a P. mascaren…
The large invasive population of Xenopus laevis in Sicily, Italy
2008
AbstractThe worldwide spread of invasive species is considered to be one of the main causes of global amphibian declines and the loss of biodiversity in general. The African Clawed Frog, Xenopus laevis, shows a strong ability to establish populations and invade various geographic regions. In 2004 X. laevis was found in Sicily for the first time. The Sicilian population is probably the largest in Europe with a range of about 225 km2 in an area characterized by numerous agricultural ponds. This high density of ponds has potentially facilitated the dispersal of X. laevis. The frogs can move far from rivers or watercourses by utilizing the ponds as suitable "islands". The analysis of their diet…
Can the introduction of Xenopus laevis affect native amphibian populations? Reduction of reproductive occurrence in presence of the invasive species
2010
Biological invasions are regarded as a form of global change and potential cause of biodiversity loss. Xenopus laevis is an anuran amphibian native to sub-Saharan Africa with strong invasive capacity, especially in geographic regions with a Mediterranean climate. In spite of the worldwide diffusion of X. laevis, the effective impact on local ecosystems and native amphibian populations is poorly quantified. A large population of X. laevis occurs in Sicily and our main aim of this work was to assess the consequences of introduction of this alien species on local amphibian populations. In this study we compare the occurrence of reproduction of native amphibians in ponds with and without X. lae…
Origin and age of Australian Chenopodiaceae
2005
Abstract We studied the age, origins, and possible routes of colonization of the Australian Chenopodiaceae. Using a previously published rbc L phylogeny of the Amaranthaceae–Chenopodiaceae alliance (Kadereit et al. 2003) and new ITS phylogenies of the Camphorosmeae and Salicornieae, we conclude that Australia has been reached in at least nine independent colonization events: four in the Chenopodioideae, two in the Salicornieae, and one each in the Camphorosmeae, Suaedeae, and Salsoleae. Where feasible, we used molecular clock estimates to date the ages of the respective lineages. The two oldest lineages both belong to the Chenopodioideae ( Scleroblitum and Chenopodium sect. Orthosporum / Dy…
Out of Asia: Mitochondrial DNA Evidence for an Oriental Origin of Tiger Frogs, Genus Hoplobatrachus
2001
Most examples of intercontinental dispersal events after the Miocene contact between Africa and Asia involve mammal lineages. Among amphibians, a number of probably related groups are known from both continents, but their phylogenies are so far largely unresolved. To test the hypothesis of Miocene dispersal against a Mesozoic vicariance scenario in the context of Gondwana fragmentation, we analyzed fragments of the mitochondrial 16S rRNA gene (572 bp) in 40 specimens of 34 species of the anuran family Ranidae. Results corroborated the monophyly of tiger frogs (genus Hoplobatrachus), a genus with representatives in Africa and Asia. The African H. occipitalis was the sister group of the Asian…
Detection of tick-borne encephalitis virus in I. ricinus ticks collected from autumn migratory birds in Latvia.
2014
Birds have a potential of spreading ticks via bird migration routes. In this study, we screened 170 ticks removed during autumn 2010 from 55 birds belonging to 10 species for the presence of tick-borne encephalitis virus (TBEV). In total, TBEV RNA was detected in 14% of I. ricinus tick samples obtained from different birds species. The results of this study indicate the possible role of migrating birds in the dispersal of TBEV-infected ticks along the southward migration route.
Population structure of Brachidontes pharaonis (P. Fisher, 1870) (Bivalvia, Mytilidae) in the Mediterranean Sea, and evolution of a novel mtDNA polym…
2006
Abstract Brachidontes pharaonis (Fisher P, 1870) is an Indo-Pacific mussel that has colonized the Mediterranean Sea via the Suez Canal. Mussels may have migrated by natural dispersal of pelagic larvae, or they may have been transported on the hulls of ships, or in ballast water, or by some combination of these. Mitochondrial COI sequences (618 bp) from 101 mussels from six localities in the central and eastern Mediterranean Sea and from one site in the Red Sea were used to describe population structure. Analysis of molecular variance indicated that frequencies differed among populations, and that 92% of the variation resided within populations. The majority of haplotypes were private allele…