1,721,021 research outputs found
Habitat selection in adult males of Alpine ibex,Capra ibex ibex
Full text linkHabitat use and selection of 14 Alpine ibex males were studied in the Gran
Paradiso National Park. Alpine meadows were always overused and positively selected, because
this habitat constituted an important food resource for the ibex. Even if rocks (30%) and stone
ravines (22%) were the most frequented habitats in the study area, their use was lower than their
availability because they offered few trophic resources. Pastures were used only in spring when
the ibexes were looking for those sites just free from snow and with fresh vegetation. Stone
ravines, where the ibexes rested in the hottest days, were most used in summer. Rocks were most
used in winter: rock-faces are the only sites where the risk of avalanches is low and where it is
still possible to find snow-free patches. Larch woods were especially used in winter and spring
when it was still possible to find snow-free patches. The home range sizes proved to be
influenced by the amount of Alpine meadows and rocks
Genetic evidence of a hybrid swarm between Alpine ibex (Capra ibex) and domestic goat (C. hircus)
Full text linkImproving the understanding of the causes and effects of anthropogenic hybridization is fundamental to ensure species conservation, particularly in the case of hybridization between wild species and their domestic relatives. Knowledge is missing for many species also because of a lack of appropriate tools for hybrid identification. Here, coupling genotype and phenotype analysis, we carried out an extensive investigation of ongoing hybridization in Alpine ibex Capra ibex, a mountain ungulate of conservation concern from a genetic perspective. By genotyping 63 diagnostic and 465 neutral SNPs, 20 suspected hybrids and 126 Alpine ibex without suspicious phenotype, representing 8 populations across a major part of the species distribution, we found evidence for ongoing hybridization between Alpine ibex and domestic goat. We identified different levels of hybridization including backcrosses into both Alpine ibex and domestic goat. Our results suggest a lack of reproductive barriers between the two species and good survival and reproductive success of the hybrids. Hybridization was locally intense, like a hybrid swarm, but not spread across the rest of the species distribution. Most of the hybrids were discovered in two locations in the north‐west of Italy, while random sampling of individuals from different areas did not provide evidence of recent hybridization. Our method, based on amplicon sequencing of 63 diagnostic SNPs specifically developed for this purpose, allowed us to identify hybrids and backcrosses up to the fourth to fifth generations and was suitable for genetic samples of different quality, although with varying levels of certainty regarding the exact number of generations passed since hybridization. Based on the paired analysis of genotype and phenotype, we provide guidelines for the first identification of hybrids in the field and suggest a procedure for the reliable identification of hybrids
Heterozygosity-fitness correlation at the major histocompatibility complex despite low variation in Alpine ibex (Capra ibex)
Full text linkCrucial for the long‐term survival of wild populations is their ability to fight diseases. Disease outbreaks can lead to severe population size reductions, which makes endangered and reintroduced species especially vulnerable. In vertebrates, the major histocompatibility complex (MHC) plays an important role in determining the immune response. Species that went through severe bottlenecks often show very low levels of genetic diversity at the MHC. Due to the known link between the MHC and immune response, such species are expected to be at particular risk in case of disease outbreaks. However, so far, only few studies have shown that low MHC diversity is correlated with increased disease susceptibility in species after severe bottlenecks. We investigated genetic variation at the MHC and its correlations with disease resistance and other fitness‐related traits in Alpine ibex (Capra ibex), a wild goat species that underwent a strong bottleneck in the last century and that is known to have extremely low genetic variability, both genome‐wide and at the MHC. We studied MHC variation in male ibex of Gran Paradiso National Park, the population used as a source for all postbottleneck reintroductions. We found that individual MHC heterozygosity (based on six microsatellites) was not correlated with genome‐wide neutral heterozygosity. MHC heterozygosity, but not genome‐wide heterozygosity, was positively correlated with resistance to infectious keratoconjunctivitis and with body mass. Our results show that genetic variation at the MHC plays an important role in disease resistance and, hence, should be taken into account for successfully managing species conservation
Seeking temporal refugia to heat stress: increasing nocturnal activity despite predation risk
Full text link: Flexibility in activity timing may enable organisms to quickly adapt to environmental changes. Under global warming, diurnally adapted endotherms may achieve a better energy balance by shifting their activity towards cooler nocturnal hours. However, this shift may expose animals to new or increased environmental challenges (e.g. increased predation risk, reduced foraging efficiency). We analysed a large dataset of activity data from 47 ibex (Capra ibex) in two protected areas, characterized by varying levels of predation risk (presence versus absence of the wolf-Canis lupus). We found that ibex increased nocturnal activity following warmer days and during brighter nights. Despite the considerable sexual dimorphism typical of this species and the consequent different predation-risk perception, males and females demonstrated consistent responses to heat in both predator-present and predator-absent areas. This supports the hypothesis that shifting activity towards nighttime may be a common strategy adopted by diurnal endotherms in response to global warming. As nowadays different pressures are pushing mammals towards nocturnality, our findings emphasize the urgent need to integrate knowledge of temporal behavioural modifications into management and conservation planning
Hormones, parasites and male mating tactics in Alpine chamois: identifying the mechanisms of life history trade-offs
No full textAlternative mating tactics (AMTs) may show different trade-offs between current reproduction and survival; however, the proximate mechanisms underlying this pattern remain unclear. Among them, the relationship between reproductive effort and parasite resistance mediated by hormonal secretion has received increasing attention. We monitored 19 marked adult male chamois, Rupicapra rupicapra, within the Gran Paradiso National Park (Italy) between the pre- and postrut 2011, to investigate the trade-off between mating effort and parasites associated with AMTs, and the underlying physiological mechanism. Territorial males sharply increased mating effort, faecal androgen and cortisol metabolites, and parasite levels during the rut, whereas nonterritorial ones displayed a similar pattern only for androgen metabolite levels. During the rut, territorial males invested more in rutting activities, while having higher levels of hormone metabolites and greater faecal counts of parasites than nonterritorial males. Before and after the rut, differences between male types (territorial and nonterritorial males) were smaller. Our analysis suggests that a trade-off between mating effort and parasitism exists, and that the proximate mechanism underlying this pattern may be found in the secretion of androgen metabolites. The greater investment in rutting activities, which territorial males make, suggests potentially high mating benefits. However, mating benefits could be counterbalanced by greater risk of injuries, consumption of fat reserves and higher hormone levels, which might favour the suppression of immunological defence and the subsequent decrease in parasite resistance
Horn growth but not asymmetry heralds the onset of senescence in male Alpine ibex (Capra ibex)
Full text linkSenescence can be defined as accelerating phenotypic deterioration with old age. For traits that grow throughout life, such as the horns of some ungulates, senescence may be expressed as a decrease in annual growth rates, or an increase in asymmetry, in the years preceding death. Age-specific yearly horn-growth segments of 378 male Alpine ibex Capra ibex L. that died from natural causes were analysed in the Gran Paradiso National Park (Italian Alps). Horn annuli displayed fluctuating asymmetry. The hypothesis that asymmetry and size of the annuli of the horns could predict annual survival probability was tested. It was found that between 5 and 11 years of age, male ibex that grew shorter annuli than the average for the population had a greater probability of mortality over the following years than those with greater rates of horn growth. Horn asymmetry and mortality rates were not significantly correlated. Annulus size, reflecting the onset of senescence, seemed to be a better indicator of individual quality than annulus asymmetry
Patterns of biodiversity in the northwestern Italian Alps: a multi-taxa approach
No full textThe current loss of biodiversity requires long-term monitoring of the distribution of living organisms, particularly in regions, such as mountains, which are highly sensitive to climatic and environmental changes. In 2007, three alpine parks in N-W Italy started a field program to determine the factors which influence animal biodiversity and identify the most appropriate methods for periodically repeatable monitoring. Twelve altitudinal transects (from montane to alpine belt) were chosen, each composed of 4-7 sampling units, for a total of 69 monitored plots. In each station, five taxonomic groups (carabids, butterflies, spiders, staphylinids, birds) were systematically sampled and topographic, environmental and micro-climatic variables were recorded. The aim was to assess the distribution of different taxa along altitudinal gradients and the relative influence of geographical, environmental and climatic factors. The data showed that species richness and community composition of invertebrates are mainly determined by altitude and microclimatic conditions, whereas birds are more sensitive to habitat structure. For invertebrates, the strong relationship with temperature suggests their potential sensitivity to climatic variations. The analysis of biodiversity patterns across vegetation belts indicated that the alpine belt hosts few species but a high percentage of endemic and vulnerable species, highlighting its importance for conservation purposes. This work offers a representative sample of the northwestern Italian Alps and it is a first step of a monitoring effort that will be repeated every five years to highlight the response of alpine biodiversity to climate and land-use changes
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
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