Search results for "Biogeography"
showing 10 items of 310 documents
How do freshwater organisms cross the “dry ocean”? A review on passive dispersal and colonization processes with a special focus on temporary ponds
2014
Lakes and ponds are scattered on Earth’s surface as islands in the ocean. The organisms inhabiting these ecosystems have thus developed strategies to pass the barrier represented by the surrounding land, to disperse and to colonize new environments. The evidences of a high potential for passive long-range dispersal of organisms producing resting stages inspired the idea that there were no real barriers to their actual dispersal, and that their distribution was only limited by the ecological characteristics of the available habitats. The development of genetic techniques allowed to criticize this view and revealed the existence of a more complex and diverse biological scenario governed by an…
First record and morphological features of Hemidiaptomus (Occidodiaptomus) ingens (Gurney, 1909) (Copepoda Calanoida) in Italy
2004
During a survey, carried out to assess the consistency of microcrustacean fauna inhabiting temporary ponds in Sicily, Hemidiaptomus (Occidodiaptomus) ingens (Gurney, 1909), a large calanoid copepod up to now known only for North-African ponds, Camargue and Corse, was found in the north-western part of the island. Due to its central location in the Mediterranean Sea, Sicily represents a transition zone where several chorological zones of the West Palearctic merge and converge. A brief summary of the existing literature regarding this taxon is given with some morphological considerations on the recently found population which represents the first record for Italy. In particular, the morpholog…
Predicting the current and future global distribution of the invasive freshwater hydrozoan Craspedacusta sowerbii
2021
AbstractThe freshwater jellyfish Craspedacusta sowerbii is one of the most widespread invasive species, but its global distribution remains uncertain due to ephemeral appearances and general lack of information in various aquatic environments. The aim of this study was to map current and future distributions (2050 and 2100) using Species Distribution Models allowing to visualize the habitat suitability and make projections of its changes under potential climate change scenarios. Except in Oceania where the range decreased, an expansion of C. sowerbii was projected during the next century under modeled future scenarios being most intensive during the first half of the century. The present st…
Cladocera (Branchiopoda, Anomopoda, Ctenopoda, and Onychopoda) from Sicilian inland waters: an updated inventory
2005
An extensive survey aimed at updating and increasing the knowledge on species richness and distribution of Cladocera (Branchiopoda) in Sicily has been carried out in the period 2000-2004. More than 250 water bodies, mainly temporary, have been sampled on the whole Sicilian territory and the circum-Sicilian islands. This sampling effort led to the discovery of several species new to the fauna of the island and, coupled with a careful bibliographic review, allowed the realization of an updated checklist that includes 57 species definitely present on the island (only 33 were formerly known), and two more, whose actual presence in Sicily is dubious and needs confirmation. The chorological spect…
Ecology and distribution of Calanoid Copepods in Sicilian inland waters (Italy)
2006
(2006). Ecology and distribution of calanoid copepods in Sicilian inland waters (Italy) SIL Proceedings, 1922-2010: Vol. 29, No. 5, pp. 2150-2156.
Benthic hydroids from the south of Livingston Island (South Shetland Islands, Antarctica) collected by the Spanish Antarctic expedition Bentart 94
2006
Twenty-five species of benthic hydroids were collected during the Spanish Antarctic expedition Bentart 94 from the south of Livingston Island (Antarctica). All species are considered regarding autecology and geographical distribution. The systematic position amongst allied species is discussed when considered necessary. Antarctoscyphus asymmetricus and Symplectoscyphus nesioticus are reported for the second and the third time, respectively.
Sicilian Temporary Ponds: An Overview of the Composition and Affinities of their Crustacean Biota
2009
Available data on Sicilian entomostracans allowed an initial characterization of the freshwater crustacean biota of the island and to formulate some hypotheses on its origin.The absence of supra-specific endemic taxa and the current regional distriburion of the investigated species suggest a late Pleistocene colonisation of the island by temperate taxa with a northern affinity, currently confined to the coolest areas of the island, followed by a Holocene arrival of thermophilous species coming from the Maghreb, which is still in progress. The importance of Sicily as a "crossroad" for the faunas of the circum-Mediterranean countries is thus confirmed.Unfortunately, and in spite of the EU dir…
Molecular phylogenetics and historical biogeography of the west-palearctic common toads (Bufo bufo species complex)
2012
In most pan-Eurasiatic species complexes, two phenomena have been traditionally considered key processes of their cladogenesis and biogeography. First, it is hypothesized that the origin and development of the Central Asian Deserts generated a biogeographic barrier that fragmented past continuous distributions in Eastern and Western domains. Second, Pleistocene glaciations have been proposed as the main process driving the regional diversification within each of these domains. The European common toad and its closest relatives provide an interesting opportunity to examine the relative contributions of these paleogeographic and paleoclimatic events to the phylogeny and biogeography of a wide…
The evolutionary history of the Arabidopsis arenosa complex: diverse tetraploids mask the Western Carpathian center of species and genetic diversity.
2012
The Arabidopsis arenosa complex is closely related to the model plant Arabidopsis thaliana. Species and subspecies in the complex are mainly biennial, predominantly outcrossing, herbaceous, and with a distribution range covering most parts of latitudes and the eastern reaches of Europe. In this study we present the first comprehensive evolutionary history of the A. arenosa species complex, covering its natural range, by using chromosome counts, nuclear AFLP data, and a maternally inherited marker from the chloroplast genome [trnL intron (trnL) and trnL/F intergenic spacer (trnL/F-IGS) of tRNA(Leu) and tRNA(Phe), respectively]. We unravel the broad-scale cytogeographic and phylogeographic pa…
Gisekia(Gisekiaceae): Phylogenetic relationships, biogeography, and ecophysiology of a poorly known C4lineage in the Caryophyllales
2014
• Premise of the study: Gisekiaceae are a monogeneric family of the core Caryophyllales distributed in arid regions of Africa and Asia. The only widespread species of the genus, Gisekia pharnaceoides, performs C4 photosynthesis based on CO2 compensation point measurements. This study investigates the C4 syndrome and its evolution in Gisekia. The infrageneric relationships, distribution and bioclimatic preferences of Gisekia are also investigated.• Methods: Leaf gas exchange characteristics, activity of Rubisco and major C4 cycle enzymes, and ultrastructural characteristics of mesophyll and bundle sheath cells are studied for Gisekia pharnaceoides. δ13C values and leaf anatomy are analyzed f…