Search results for "Biological dispersal"

An alien ectosymbiotic branchiobdellidan (Annelida: Clitellata) adopting exotic crayfish: a biological co-invasion with unpredictable consequences

2015

Invasive alien species present a global threat to biodiversity, particularly where pathogens and symbionts are involved. Branchiobdellidans are clitellate annelids with an obligate ectosymbiotic association primarily on astacoidean crayfish. There are several examples of branchiobdellidan species adopting a geographically exotic host where endemic and exotic crayfishes cohabit the same water body. The first records of a western North American branchiobdellidan, Xironogiton victoriensis , adopting the eastern North American crayfish, Procambarus clarkii , in 2 river basins in Spain provide further evidence of the ectosymbionts’ tolerance to adopt an exotic host. Given worldwide translocation…

Filamentous fungi transported by birds during migration across the mediterranean sea.

2013

The potential for the transport and diffusion of some pathogenic microorganisms by migratory birds is of concern. Migratory birds may be involved in the dispersal of microorganisms and may play a role of mechanical and biological vectors. The efficiency of dispersal of pathogenic microorganisms depends on a wide range of biotic and abiotic factors that influence the survival or disappearance of a given agent in a geographical area. In the present study, 349 migratory birds were captured in four sites (Mazara del Vallo, Lampedusa, Ustica and Linosa), representing the main stop-over points during spring and autumnal migration, and analyzed for the presence of filamentous fungi. A total of 2,3…

Pleistocene allopatric differentiation followed by recent range expansion explains the distribution and molecular diversity of two congeneric crustac…

2021

AbstractPleistocene glaciations had a tremendous impact on the biota across the Palaearctic, resulting in strong phylogeographic signals of range contraction and rapid postglacial recolonization of the deglaciated areas. Here, we explore the diversity patterns and history of two sibling species of passively dispersing taxa typical of temporary ponds, fairy shrimps (Anostraca). We combine mitochondrial (COI) and nuclear (ITS2 and 18S) markers to conduct a range-wide phylogeographic study including 56 populations of Branchinecta ferox and Branchinecta orientalis in the Palaearctic. Specifically, we investigate whether their largely overlapping ranges in Europe resulted from allopatric differe…

The East African Orogen: New Zircon and Nd Ages and Implications for Rodinia and Gondwana Supercontinent Formation and Dispersal

2001

From Europe to Africa and vice versa: evidence for multiple intercontinental dispersal in ribbed salamanders (Genus Pleurodeles)

2004

Aim  The intricate puzzle-like geography of the western Mediterranean is a product of long-term tectonic and orogenic events, supplemented by repeated climatic oscillations since the Pliocene. It offers numerous vicariance events that may be invoked to explain speciation in amphibians. We test for plausibility of two mutually exclusive Iberian–African vicariance hypotheses to explain the basal split within newts of the genus Pleurodeles: (1) the disconnection of the Betic arch c. 14 Ma and (2) the end of the Messinian salinity crisis 5.33 Ma. Location  Specimens of P. waltl and P. poireti were sampled from 32 populations in Portugal, Spain, Morocco, Algeria and Tunisia. Methods  Parts of th…

Forests as dispersal barriers for Erebia medusa (Nymphalidae, Lepidoptera)

2000

Summary The nymphalid butterfly Erebia medusa is a typical species of meadows that are poor in nitrogen and fallow land. In forests, it is only found on clearings with meadow-like structures. However, it is missing on wind exposed places, too. 239 imagoes of E. medusa were sampled in the Aggtelek Karst region (north-eastern Hungary) at six different localities at the end of May 1997. The sample sizes varied between 33 and 46. The studied karst area has a typical forest steppe vegetation and is characterised by a mosaic-like distribution of meadows and forests. The sampled butterflies were analysed by allozyme electrophoresis. The level of polymorphism was significantly higher in the samples…

Widespread secondary contact and new glacial refugia in the halophilic rotifer Brachionus plicatilis in the Iberian Peninsula.

2011

Small aquatic organisms harbour deep phylogeographic patterns and highly structured populations even at local scales. These patterns indicate restricted gene flow, despite these organisms' high dispersal abilities, and have been explained by a combination of (1) strong founder effects due to rapidly growing populations and very large population sizes, and (2) the development of diapausing egg banks and local adaptation, resulting in low effective gene flow, what is known as the Monopolization hypothesis. In this study, we build up on our understanding of the mitochondrial phylogeography of the halophilic rotifer Brachionus plicatilis in the Iberian Peninsula by both increasing the number of…

Habitat effects on population connectivity in a coastal seascape

2014

Published version of an article from: Marine Ecology Progress Series. Also available from Inter Research: http://dx.doi.org/10.3354/meps10944 Knowing how population connectivity varies across heterogeneous habitats can provide insight into the mechanisms underlying population structuring, and ultimately help to inform conservation and management actions. We studied whether the spatial extent of connectivity in coastal Atlantic cod Gadus morhua varied with coastal topography, hypothesizing that connectivity during all life stages would be greater among open, exposed habitats compared to sheltered, fjord-like habitats. We tested this hypothesis using (1) an extensive mark-recapture data set t…

Genetic population structure of Epinephelus marginatus (Pisces, Serranidae) revealed by two molecular markers

2006

In this paper, data are presented regarding the population structure of dusky grouper (Epinephelus marginatus) which was sampled in the Mediterranean Sea and Atlantic Ocean using two different molecular markers, ND2 RFLP and cytochrome b (cyt b) sequence analysis. The main objective of the study is to analyse the genetic variability of E. marginatus in the Mediterranean Sea to define how the biological characteristics of the species, such as the dispersal capability of pelagic larvae and the benthonic-sedentary life style, can affect the genetic population structure or maintaining the gene flow or determining genetic differences. Furthermore, we considered an Atlantic sample to establish th…

Flower and fruit structure of the endangered species Petagnaea gussonei (Sprengel) Rauschert (Saniculoideae, Apiaceae) and implications for its repro…

2015

Petagnaea gussonei (Apiaceae) is an endangered species endemic to the Nebrodi mountains (north-eastern Sicily). Although an increasing number of studies have been performed on this species, its reproductive biology remains poorly understood. The aim of this study was to investigate in detail the structure of the flower and the fruit of Petagnaea, and the possible implications for its breeding system and seed dispersal mechanism. Results from fieldwork, light microscopy and scanning electron microscopy suggest (1) the presence of protandrous hermaphrodite flowers; (2) geitonogamy, autogamy, and allogamy as breeding system mechanisms of P. gussonei, even if asexual reproduction is preferred b…