Search results for "Distance"
showing 10 items of 1009 documents
Substantial decline of Northern European peatland bird populations: Consequences of drainage
2017
Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peat land species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habit…
Does the genetic diversity among pubescent white oaks in southern Italy, Sicily and Sardinia islands support the current taxonomic classification?
2020
AbstractMolecular diversity analysis of deciduous pubescent oaks was conducted for populations from Calabria, Sicily and Sardinia. The aims of this study were twofold. First, to provide data on the genetic diversity of pubescent oaks from an understudied area which currently exhibits one of the highest concentrations of pubescent oak species in Europe. Second, to verify if these groups of oaks are genetically distinct and if their identification is in accordance with the current taxonomic classification. Molecular analyses of leaf material of 480 trees from seventeen populations belonging to putatively different pubescent oak species (Quercus amplifolia,Q. congesta,Q. dalechampii,Q. ichnusa…
Genetic relationships between Sicilian wild populations of Brassica analysed with RAPD markers
2001
Brassica comprises very variable species, both morphologically and genetically. Among these species, the Sicilian populations of Brassica sect. Brassica, species related to kale crops form a complex group. The genetic relationships among 15 populations occurring in Sicily and one from Calabria, representing the existing diversity, have been investigated using random amplified polymorphic DNA (RAPD) markers. This assay, carried out with 22 arbitrary primers, generated 236 polymorphic fragments, 21 of which were specific for single populations (mainly Brassica insularis, Brassica incana and Brassica macro-carpa). Jaccard's genetic distances were computed and the phylogenic tree was establishe…
Pleurotus opuntiae revisited e An insight to the phylogeny of dimitic Pleurotus species with emphasis on the P. djamor complex
2018
Abstract The name Pleurotus opuntiae is indiscriminately used for describing mushrooms with white to off-white to white-grey pilei with short or absent stipe and dimitic hyphal system, which grow on plants of the genera Opuntia, Yucca, Agave, Phytolacca etc. However, the outcome of the present study evidences that this name should be reserved for specimens deriving from the Mediterranean area only; an epitype originating from Italy on Opuntia ficus-indica is designated. Pertinent material was sequenced by using the internal transcribed spacer region (ITS) and found to be phylogenetically related to P. djamor from Kenya and Nigeria, while members of the P. djamor complex from other continent…
Comparison of Bayesian and numerical optimization-based diet estimation on herbivorous zooplankton
2020
Consumer diet estimation with biotracer-based mixing models provides valuable information about trophic interactions and the dynamics of complex ecosystems. Here, we assessed the performance of four Bayesian and three numerical optimization-based diet estimation methods for estimating the diet composition of herbivorous zooplankton using consumer fatty acid (FA) profiles and resource library consisting of the results of homogeneous diet feeding experiments. The method performance was evaluated in terms of absolute errors, central probability interval checks, the success in identifying the primary resource in the diet, and the ability to detect the absence of resources in the diet. Despite …
Whistle variation in Mediterranean common bottlenose dolphin: The role of geographical, anthropogenic, social, and behavioral factors.
2020
Abstract The studies on the variation of acoustic communication in different species have provided insight that genetics, geographic isolation, and adaptation to ecological and social conditions play important roles in the variability of acoustic signals. The dolphin whistles are communication signals that can vary significantly among and within populations. Although it is known that they are influenced by different environmental and social variables, the factors influencing the variation between populations have received scant attention. In the present study, we investigated the factors associated with the acoustic variability in the whistles of common bottlenose dolphin (Tursiops truncatu…
Fine-scale spatial genetic structure and gene dispersal in Silene latifolia
2010
Plants are sessile organisms, often characterized by limited dispersal. Seeds and pollen are the critical stages for gene flow. Here we investigate spatial genetic structure, gene dispersal and the relative contribution of pollen vs seed in the movement of genes in a stable metapopulation of the white campion Silene latifolia within its native range. This short-lived perennial plant is dioecious, has gravity-dispersed seeds and moth-mediated pollination. Direct measures of pollen dispersal suggested that large populations receive more pollen than small isolated populations and that most gene flow occurs within tens of meters. However, these studies were performed in the newly colonized rang…
Distance decay 2.0 – a global synthesis of taxonomic and functional turnover in ecological communities
2021
AbstractUnderstanding the variation in community composition and species abundances, i.e., β-diversity, is at the heart of community ecology. A common approach to examine β-diversity is to evaluate directional turnover in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distances. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 149 datasets comprising different types of organisms and environments. We modelled an exponential distance decay for each dataset using generalized linear models and extracted r2 and slope to analyse the streng…
Diversifying selection on MHC class I in the house sparrow (Passer domesticus).
2009
10 pages; International audience; Genes of the major histocompatibility complex (MHC) are the most polymorphic loci known in vertebrates. Two main hypotheses have been put forward to explain the maintenance of MHC diversity: pathogen-mediated selection and MHC-based mate choice. Host-parasite interactions can maintain MHC diversity via frequency-dependent selection, heterozygote advantage, and diversifying selection (spatially and/or temporally heterogeneous selection). In this study, we wished to investigate the nature of selection acting on the MHC class I across spatially structured populations of house sparrows (Passer domesticus) in France. To infer the nature of the selection, we comp…
Drosophila cuticular hydrocarbons revisited : Mating status alters cuticular profiles
2010
Editor: Frederic Marion-Poll, INRA - Paris 6 - AgroParisTech, France.; International audience; Most living organisms use pheromones for inter-individual communication. In Drosophila melanogaster flies, several pheromones perceived either by contact/at a short distance (cuticular hydrocarbons, CHs), or at a longer distance (cis-vaccenyl acetate, cVA), affect courtship and mating behaviours. However, it has not previously been possible to precisely identify all potential pheromonal compounds and simultaneously monitor their variation on a time scale. To overcome this limitation, we combined Solid Phase Micro-Extraction with gas-chromatography coupled with mass-spectrometry. This allowed us (i…