1,721,019 research outputs found
Demographic projections of the Apennine brown bear population Ursus arctos marsicanus (Mammalia: Ursidae) under alternative management scenarios
Full text linkApennine brown bears are a very small, isolated population of central Italy, consisting of about 50 individuals and under a severe risk of extinction.We performed a population viability analysis (PVA) for this population, contrasting a deterministic model and an individual-based stochastic model, using a set of demographic parameters estimated for the same population during the last decade. We also built a set of simulated management scenarios, in which we compared the effectiveness of alternative conservation measures and assessed the susceptibility of the population to catastrophic mortality events. The deterministic model produced an estimate of the asymptotic population growth rate r = 0.001, corresponding to an asymptotically stable population. The stochastic model produced an estimate of r = − 0.013 (standard deviation = 0.103), corresponding to an annual population decrease of 1.3%, a 17% extinction risk in 100 years, an average population of 27 bears for non-extinct populations, and an average time to extinction of 81 years for those gone extinct. Extinction probability increased to more alarming levels (> 0.4) when at least one catastrophic event occurred during a 100-year period. Current vital rates of the population are not compatible
with a more than negligible numerical increase, and this bear population is likely to remain small and exposed to a relatively high risk of extinction, if the average survival or reproductive rates do not increase. Management efforts aimed to increase food availability generated minimal to moderate variations in population growth rate and in the associated risk of extinction, whereas interventions meant to reduce adult female mortality were highly effective in increasing persistence probability. We propose that the general objectives of the action plan for the conservation of the Apennine brown bear for the incoming decade should explicitly contemplate quantitative demographic goals, focusing in particular on adult female and cub mortality
Assessing trends in wolf impact on livestock through verified claims in historical vs. recent areas of occurrence in Italy
No full textAs wolves in Europe are expanding in range, their impact on economic activities through predation on livestock is increasing. In this context, the effectiveness of damage compensation programs is being debated and requires adequate assessment. With this aim, we performed a survey of wolf depredation on livestock in Italy during the years 2010 − 2014, comparing regions of historical and more recent wolf occurrence. We collected data on livestock depredations, prevalent husbandry practices and the main features of compensation schemes. We investigated the effect of several ecological and management-related variables on the extent of wolf impact. On average, 3274 (± 195.2 SD) wolf depredation events were compensated across Italy each year, comprising 7809 (± 1278.9 SD) livestock heads, and corresponding to € 1,450,814 (± € 184,762 SD) annual compensation costs. Regions recently recolonized by wolves reported lower and decreasing levels of impact compared to those with historical wolf presence. Half of all depredations occurred in 121 municipalities (9.7% of the total), which emerged as hotspots of impact and economic cost for the system. The proportion of farms with chronically recurring damage increased by 80% in the southern Apennines, where wolves never disappeared, whereas it declined by 100% in the Alps, due to effective prevention measures implemented following wolf recolonization in the mid-1990s. Long-term human-wolf coexistence does not necessarily correspond to lower damage levels and effective conflict management, casting doubts on the effectiveness and sustainability of compensation programs, if applied without reference to a context of adaptive management
Correlates of parasites and pseudoparasites in wolves (Canis lupus) across continents: A comparison among Yellowstone (USA), Abruzzo (IT) and Mercantour (FR) national parks
Full text linkLittle is known about the impact of infectious diseases on large carnivores. We investigated factors structuring the helminth and protozoan infections of wolves (Canis lupus) by using coprological analyses. Faecal samples (n = 342) were analysed from 11 wolf packs belonging to three different geographical and ecological settings in Italy (Abruzzo, Lazio e Molise National Park, PNALM: 4 packs, 88 samples), in France (Mercantour National Park, PNM: 4 packs, 68 samples) and in the U.S.A. (Yellowstone National Park, YNP: 3 packs, 186 samples). Parasites were found in 29.4%–88.6% of the samples and parasite taxa ranged from four to ten in each study area. Taeniidae (Taenia/Echinococcus), Sarcocystis spp. and Toxascaris leonina were most common in faecal samples from YNP, whereas Capillaria spp., Taeniidae and Uncinaria stenocephala were predominant in PNALM. We used generalised linear mixed models to assess the relationship between parasite infection or the number of parasite taxa and selected ecological drivers across study areas. Significant effects illustrated the importance of the ecological factors such as occurrence of free-ranging dogs, diet composition and wolf density, as well as the ancestry of the wolf populations, in shaping parasite-wolf communities. Additional investigations are needed to elucidate the impact of parasitic infections on wolf populations, as well as the role of anthropogenic factors in facilitating parasitic diffusion to apex predators
High levels of recent wolf × dog introgressive hybridization in agricultural landscapes of central Italy
No full textRepresenting a form of anthropogenic hybridization, wolf–dog interbreeding may potentially compromise the ecological and evolutionary traits of local wolf populations and corrode social tolerance towards wolves. However, estimates of the extent of wolf–dog hybridization in wolf populations are scarce, especially at a multi-pack scale and in human-dominated landscapes. Using non-invasive (n = 215) and invasive (n = 25) samples of wolf-like canids collected in the Province of Grosseto (central Italy, 2012–2014), we assessed the extent of wolf–dog hybridization based on multi-locus genotypes (16 and 49 loci for non-invasive and invasive samples, respectively) and Bayesian clustering techniques. Based on a total of 72 genotypes, the minimum proportion of admixed individuals in our sample was 30.6%, comprising 8 out of the 13 surveyed packs; however, by correcting for the proportion of admixed individuals undetected using the 16-loci compared with the 49-loci marker set (26.7%), we suspect the rate of recent admixture could be closer to 50%. While we did not detect any F1 hybrid, four admixed individuals had a non-negligible probability of being first-generation backcrosses, one of which likely derived from a backcross of a F1 hybrid into the dog population. Complementary genetic markers (i.e., Y-haplotype and K-locus) or anomalous morphological traits further indicated widespread occurrence of admixed individuals of older generations of backcross. This high level of admixture raises serious wolf conservation concerns and exemplifies the expected dynamics of wolf–dog hybridization if left unmanaged in human-dominated landscapes. The implications of our findings need to be urgently upscaled for the implementation of management interventions that cannot be procrastinated any longer at the regional and national scale
Cost of coexisting with a relict large carnivore population: Impact of apennine brown bears, 2005–2015
Full text linkHuman-carnivore conflicts are a major conservation issue. As bears are expanding their range in Europe’s human-modified landscapes, it is increasingly important to understand, prevent, and address human-bear conflicts and evaluate mitigation strategies in areas of historical coexis-tence. Based on verified claims, we assessed costs, patterns, and drivers of bear damages in the relict Apennine brown bear population in the Abruzzo Lazio and Molise National Park (PNALM), central Italy. During 2005–2015, 203 ± 71 (SD) damage events were verified annually, equivalent to 75,987 ± 30,038 €/year paid for compensation. Most damages occurred in summer and fall, with livestock depredation, especially sheep and cattle calves, prevailing over other types of damages, with apiaries ranking second in costs of compensation. Transhumant livestock owners were less impacted than residential ones, and farms that adopted prevention measures loaned from the PNALM were less susceptible to bear damages. Livestock farms chronically damaged by bears represented 8 ± 3% of those annually impacted, corresponding to 24 ± 6% of compensation costs. Further improvements in the conflict mitigation policy adopted by the PNALM include integrated prevention, conditional compensation, and participatory processes. We discuss the implications of our study for Human-bear coexistence in broader contexts
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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