1,721,011 research outputs found
Il Gallo forcello in ambiente alpino
No full textIn light of rapidly decreasing biodiversity, conservation efforts aimed at the sustainable management of animal species and their habitats is becoming increasingly relevant. The black grouse (Lyrurus tetrix) is listed as ‘Least Concern’ by the International Union for Conservation of Nature. However, at the southern edges of its range, this species is often fragmented, and some populations are classified as threatened. Importantly for conservation actions, the genetic ‘health’ of this elusive species in these regions is poorly understood. Here we have applied a Genotyping by Sequencing (GBS) approach to identify thousands of single nucleotide polymorphisms (SNP) across the genome of the black grouse over its Alpine range, where it is of conservation concern. These numerous markers are then used to investigate spatial and temporal patterns of genetic variation and population structure, which in turn help to discern the natural and anthropogenic factors affecting these patterns in the black grouse. Knowledge of the impact of these factors allow us to suggest conservation actions. In total, 400 tissue samples were collected from hunting bags across the Italian Alps (from Liguria to Friuli- Venezia Giulia) over a 20-year period. Overall, we found that the black grouse is currently a panmictic population across the Italian Alps; that is, gene flow is high between neighbouring areas. In addition, levels of genetic variability are good and have not decreased over the last 20 years, suggesting that current management practices (including limited hunting of male black grouse) are suitable for maintaining genetic diversity. However, the data suggest that the black grouse populations east and west of Lake Como and Val Chiavenna have diverged, possibly as a result of unfavourable reproductive conditions, such as the higher level of rainfall in this area compared to the rest of the southern Alps. In addition, this species may not disperse willingly over the large expanse of Lake Como, which is also flanked by busy highways. In general, our study results suggest that the maintenance of suitable continuous habitat (or habitat corridors where this is not possible) would facilitate the dispersal of these shy grouse and prevent population isolation in the future. For this reason, we also suggest that the number and distribution of hunted animals should be re-assessed not only according to demographic criteria, but also by identifying and preserving key areas where dispersal and gene flow takes place. In fact, although our data did not reveal any genetic isolation, fragmentation of suitable habitats and subdivision into a large number of differently connected subpopulations with highly variable population densities, remain among the main threats to conservation of the black grouse
Distribuzione geografica e temporale della variabilità genetica e genomica di due specie di tetraonidi in territorio trentino: pernice bianca (Lagopus muta) e fagiano di monte (Lyrurus tetrix)
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Identification and characterization of microsatellite markers in Hermann's tortoise (Testudo hermanni, Testudinidae)
No full textThe isolation and characterization of six polymorphic loci from a Testudo hermanni genomic library is reported. Enrichment was performed for AC but four of the characterized microsatellites present also an additional motif. Variability was tested on populations of the two recognized subspecies, Testudo hermanni hermanni and Testudo hermanni boettgeri. For one locus, a size range specific for the subspecies T. h. hermanni was observed. These are the first primers identified directly in the genome of T. hermanni
Investigating geographic and temporal genetic variation in the black grouse (Lyrurus tetrix) in the Italian Alps
Full text linkThe black grouse (Lyrurus tetrix) is a Galliform distributed across northern Eurasia, and is a game bird in
most EU countries. Although the species is listed as ‘Least Concern’ by the IUCN, populations at the
western and southern edges of its range are considered ‘Vulnerable’ due to increasing habitat
fragmentation and human disturbance. Between 1995 and 2017, in collaboration with several hunting
associations, we collected more than 600 black grouse samples across seven regions of the Italian Alps.
Ten microsatellite markers (STRs) and 2442 Single Nucleotide Polymorphisms (SNPs) were analysed in
large subsets of the collected data, with the aim of identifying environmental, temporal and anthropic
factors that affect the distribution and level of genomic variation. The main factor shaping the genetic
distances between populations based on STRs is the geographic distance between them (i.e. isolation-bydistance), but even the populations on the two extremes of our sampling area are very similar (Fst between
the two regions = 0.053). SNP data supports the STR analysis. However, isolation-by-resistance methods
for the larger STR data set show that both higher altitudes and urban areas inhibit movement of grouse
between populations. While temporal analysis of STRs for the Trentino-Alto Adige region showed no
significant change in the mean number of alleles and allelic size range between the two time frames
studied (e.g. mean number of alleles 1995-1999: 8.8, 2009-2010: 8.2), and the expected heterozygosity
was high in both time frames (1995-1999: 0.740, 2009-2010: 0.722). While black grouse population size
is reportedly decreasing, our results suggest there is no measurable genetic impact from this trend. Hence
this dataset provides a basis for future monitoring of genetic diversity in this charismatic alpine species
Do it right or don't do it at all! Genetic screening of S. marmoratus exemplifies the need to revise many or most salmonid conservation and restocking programmes
Full text linkDemographic collapse of Italian trout populations, owing to the last century freshwater quantitative and qualitative impoverishment, was contrasted by massive stocking of exotic congenerics to sustain angling pressure. After the restoration - or at least regulation - of sustainable water use and management, the envisaged solution to halt population depletion turned out to be the new problem: all native Italian trout populations resulted to be heavily impacted by Atlantic brown trout through hybridisation and genetic introgression. In order to contrast the native trout decline, dozens of projects based on captive breeding programs were then started. Despite a formal general agreement that supportive or supplemental breeding should base on strong genetic data, in order to recover and conserve micro-scale diversity and evolutionary significant units, most breeding programs - sustained by from the smallest local angling association up to the European Community - still exclusively depend on i) morphological selection of breeders, ii) maintenance of captive semi-domesticated breeding stocks, and/or iii) stocking of selected conspecific from different water systems. The outcome of such management actions is, at times, favouring a phenotypic shift of hybrids to the expected or desired morphology patterns, accelerating introgression by fostering the reproduction of hybrids, promoting artificial versus natural selection in non-natural breeding conditions, depleting local biodiversity by mixing and homogenising different management units.
We here report a multi-year case study on a drainage-scale management plan of marble trout (Salmo marmoratus) in the North – East of Italy. We present the outcomes of an extensive genetic screening of breeding stocks derived from different generations of phenotype selection and maintained for supportive breeding, demonstrating all the main limitations of such a scheme; we introduce the shift to supplemental breeding, based on strict genetic evaluation of wild spawners; and we finally show the first evaluation of the qualitative and quantitative effects of this change of pace.
We thus try to exemplify the way to avoid that the foreseen solution to the problem, i.e. conservation projects, will once more translate to the next and final sprint in the race to native trout genomic extinction
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