1,721,208 research outputs found
A multiple data source approach to improve abundance estimates of small populations: the brown bear in the Apennines, Italy
No full textWhen dealing with small populations of elusive species, capture-recapture methods suffer from sampling and analytical limitations, making abundance assessment particularly challenging. We present an empirical and theoretical evaluation of multiple data source sampling as a flexible and effective way to improve the performance of capture-recapture models for abundance estimation of small populations. We integrated three data sources to estimate the size of the relict Apennine brown bear (Ursus arctos marsicanus) population in central Italy, and supported our results with simulations to assess the robustness of multiple data source capture-recapture models to violations of main assumptions. During May-August 2008, we non-invasively sampled bears using systematic hair traps on a grid of 41 5 x 5 km cells, moving trap locations between five sampling sessions. We also live-trapped, ear-tagged, and genotyped 17 bears (2004-2008), and integrated resights of marked bears and family units (July-September 2008) into a multiple data source capture-recapture dataset. Population size was estimated at 40 (95% CI = 37-52) bears, with a corresponding closure-corrected density of 32 bears/1000 km(2) (95% CI = 28-36). Given the average capture probability we obtained with all data sources combined ((p) over cap = 0.311), simulations suggested that the expected degree of correlation among data sources did not seriously affect model performance, with expected level of bias <5%. Our results refine previous simulation work on larger populations, cautioning on the combined effect of lack of independence and low capture probability in application of multiple data source sampling to very small populations (N < 100). (C) 2012 Elsevier Ltd. All rights reserved
Noninvasive sampling and genetic variability, pack structure, and dynamics in an expanding wolf population
No full textAfter centuries of population decline and range contraction, gray wolves (Canis lupus) are now expanding in Europe. Understanding wolf social structure and population dynamics and predicting their future range expansion is mandatory to design sound conservation strategies, but field monitoring methods are difficult or exceedingly expensive. Noninvasive genetic sampling offers unique opportunities for the reliable monitoring of wolf populations. We conducted a 9-year-long monitoring program in a large area (approximately 19,171 km 2) in northern Italy, aiming to identify individuals, estimate kinship, reconstruct packs, and describe their dynamics. Of 5,065 biological samples (99% scats), we genotyped and sexed 44% reliably using 12 unlinked autosomal microsatellites, 4 Y-linked microsatellites, and a diagnostic mitochondrial DNA control-region sequence. We identified 414 wolves, 88 dogs, and 16 wolf × dog hybrids. Wolves in the study area belonged to at least 42 packs. We reconstructed the genealogy of 26 packs. The mean pack size was 5.6 ± 2.4 SD, including adoptees, with a mean minimum pack home range of 74 km2 ± 52 SD. We detected turnovers of breeding pairs in 19% of the packs. Reproductive wolves were unrelated and unrelated dispersers founded new packs, except for 1 pack founded by a brother-sister pair. We did not detect multiple breeding females in any packs. Overall, the population was not inbred. We found significant isolation by distance and spatial autocorrelation, with nonrandom genetic structure up to a distance of approximately 17 km. We detected 37 dispersers, 14 of which became breeders in new or already existing packs. Our results can be used to model habitat use by wolves, to estimate survival rates, to predict future expansion of the wolf population, and to build risk maps of wolf-human conflicts. © 2014 American Society of Mammalogists
Black coats in an admixed wolf x dog pack is melanism an indicator of hybridization in wolves?
No full textThe use of functional mutations, in addition to standard noncoding molecular markers, can help to detect hybridization and gene introgression in wild canid populations. We analyzed ancestry of a canid pack breeding in Central Italy that showed black coats and other unusual morphological traits suggesting wolf x dog hybrid origins. Individuals were identified by genotyping excremental DNA at 13 autosomal microsatellites, mtDNA control region sequences, a male-specific restriction site on the ZFX/Y gene to determine the gender of the individuals, four Y-linked microsatellites to determine male haplotypes, and two melanistic mutations: a SNP at exon 4 of the Agouti locus and a 3-bp deletion at a beta-Defensin gene, the K locus. Results showed that: (1) the pack was founded by a single breeding pair of related individuals, probably brother and sister, and no immigrant was detected; (2) parents and offspring showed signals of admixture at autosomal microsatellites; and (3) the melanistic K locus deletion was present in the black-coated female parent and in 8/14 offspring, but it was absent in the wild type male parent. This deletion was found also in 17/40 village dogs randomly sampled from nearby areas, but it was absent in a random sample of 40 Italian wolves. These findings suggest that the pack received the K locus deletion from dogs. Admixture analyses of empirical and simulated genotypes indicate the parents of the pack originated through a single hybridization event at least two generations back. Genetic and phenotypic assessments of coat color mutations can contribute to investigation of the origin and dynamics of functional polymorphisms in hybridizing wolf populations and to develop appropriate guidelines to contrast hybridization with their domesticated relatives
First data on north-eastern distribution of the Apennine brown bear (Ursus arctos marsicanus) using non invasive genetic sampling
No full textShe gets many and she chooses the best:Polygynandry in Salamandrina perspicillata (Amphibia: Salamandridae)
No full textPolyandry is a widespread mating strategy, found in a broad number of taxa. Among amphibians, polyandry, and multiple paternity as its direct consequence, is quite common in salamanders, especially within Ambystomatidae and Plethodontidae. In the suborder Salamadroidea the existence of two different types of spermatheca allows several kinds of polyandry strategies to appear. We used multilocus microsatellite genotyping to investigate the presence of polyandry and its effects on the paternity in a previously unstudied species with a terrestrial habit, Salamandrina perspicillata. We collected gravid females in their natural habitat and analysed the paternity of the offspring by using the software COLONY and GERUD. We found that all the analysed clutches had been fertilized by 2-4 males and that in every clutch one male had sired most of the offspring. Our results confirmed that polyandry is an important component of the mating system of this species, suggesting that females are able to recognize the sperm of the male that will provide a genetic benefit for their offspring. We found evidence of female cryptic choice based on males' genetic dissimilarity: (1) males who sire most of the offspring of a given female tend to be genetically different from their sexual partner; (2) a same male, when mated with two females, sired a proportion of the offspring inversely correlated with his genetic similarity to the female; (3) genetic dissimilarity between mating partners is positively correlated with offspring heterozygosity. According to the genetic compatibility model, we hypothesized that in the observed non resource-based mating system the indirect benefit for the offspring should reflect interactions between paternal and maternal genomes rather than the inheritance of the so-called 'good genes'. This study suggests a polygynandrous mating system for the study species and provides the first report in a salamandrid species in natural condition that reproductive success of males is correlated with genetic dissimilarity between mates. Moreover, we found evidence of an offspring benefit (higher heterozygosity) derived from the most genetically dissimilar father.</p
Unravelling the evolutionary history and future prospects of endemic species restricted to former glacial refugia
Full text linkThe contemporary distribution and genetic composition of biodiversity bear a signature of species’ evolutionary histories and the effects of past climatic oscillations. For many European species, the Mediterranean peninsulas of Iberia, Italy and the Balkans acted as glacial refugia and the source of range recolonization, and as a result, they contain disproportionately high levels of diversity. As these areas are particularly threatened by future climate change, it is important to understand how past climatic changes affected their biodiversity. We use an integrated approach, combining markers with different evolutionary rates and combining phylogenetic analysis with approximate Bayesian computation and species distribution modelling across temporal scales. We relate phylogeographic processes to patterns of genetic variation in Myotis escalerai, a bat species endemic to the Iberian Peninsula. We found a distinct population structure at the mitochondrial level with a strong geographic signature, indicating lineage divergence into separate glacial refugia within the Iberian refugium. However, microsatellite markers suggest higher levels of gene flow resulting in more limited structure at recent time frames. The evolutionary history of M. escalerai was shaped by the effects of climatic oscillations and changes in forest cover and composition, while its future is threatened by climatically induced range contractions and the role of ecological barriers due to competition interactions in restricting its distribution. This study warns that Mediterranean peninsulas, which provided refuge for European biodiversity during past glaciation events, may become a trap for limited dispersal and ecologically limited endemic species under future climate change, resulting in loss of entire lineages.Peer reviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Why do wolves eat livestock?:Factors influencing wolf diet in northern Italy
No full textThanks to protection by law and increasing habitat restoration, wolves (Canis lupus) are currently re-colonizing
Europe fromthe surviving populations of Russia, the Balkan countries, Spain and Italy, raising the need to update
conservation strategies. A major conservation issue is to restore connections and gene flow among fragmented
populations, thus contrasting the deleterious consequences of isolation. Wolves in Italy are expanding from the
Apennines towards the Alps, crossing the Ligurian Mountains (northern Italy) and establishing connections
with the Dinaric populations. Wolf expansion is threatened by poaching and incidental killings, mainly due to
livestock depredations and conflicts with shepherds, which could limit the establishment of stable populations.
Aiming to find out the factors affecting the use of livestock by wolves, in this study we determined the composition
of wolf diet in Liguria. We examined 1457 scats collected from 2008 to 2013. Individual scats were genotyped
using a non-invasive genetic procedure, and their content was determined using microscopical analyses.
Wolves in Liguria consumed mainly wild ungulates (64.4%; in particular wild boar Sus scrofa and roe deer
Capreolus capreolus) and, to a lesser extent, livestock (26.3%; in particular goats Capra hircus). We modeled the
consumption of livestock using environmental features, wild ungulate community diversity, husbandry characteristics
and wolf social organization (stable packs or dispersing individuals).Wolf diet varied according to years
and seasons with an overall decrease of livestock and an increase ofwild ungulate consumption, but also between
packs and dispersing individuals with greater livestock consumption for the latter. The presence of stable packs,
instead of dispersing wolves, the adoption of prevention measures on pastures, roe deer abundance, and the
percentage of deciduous woods, reduced predation on livestock. Thus, we suggest promoting wild ungulate
expansion, the use of prevention tools in pastures, and supporting wolf pack establishment, avoiding lethal
control and poaching, to mitigate conflicts between wolf conservation and husbandry
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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