1,720,967 research outputs found
Catching roe deer with box-traps: lesson learned from a decadal experience
No full textThe study of animal movement necessarily relies on the acquisition of data from tagged animals and is thus strongly dependent on the capture success of the target individuals. Box trapping is a quite common methodology implemented to live-catch animals, especially in those contexts where the adoption of other methodologies such as drive nets is logistically complex (e.g., in mountain environments) and/or tele-anesthesia is not a viable option. Despite their wide usage by field ecologists and wildlife managers, we feel that information about the best practices to successfully capture animals through box-trapping remains quite often in the grey literature. Therefore, we present the lesson learned from over 10 years of box-trapping activity on roe deer (Capreolus capreolus) in an alpine environment, where we captured more than 100 individuals in two different study sites. We describe all the phases of roe deer captures, from pre-baiting to the release of the animals, showing the modalities that increment capture success but also the mistakes to be avoided. Among other, we investigate circadian patterns in the capture probability, as well as the link between animal immediate post-release behavior and capture-to-handling interval. Based on the above, we propose a ‘vademecum’ on capture modalities that we hope can be beneficial to ecologists and wildlife managers for tagging wildlife of interest
Wildlife response to human functional disturbance: a case study during the Anthropause
No full textAnimal species are subject to two main different forms of an thropogenic disturbance, i.e. structural (e.g., presence of bar riers or habitat fragmentation) or functional (e.g., actual human presence for hunting or recreational activities). With specific reference to the latter, animals adopt a series of behavioural adaptations to cope with human disturbance, for example by switching their activity patterns towards night-time to minimize the risk of being hunted, or to reduce the temporal overlap with human activities, especially in highly anthropized environments. Examining the degree of behavioural plasticity of animal spe cies in relation to modifications of anthropogenic disturbance is therefore essential to fully understand the impact of humans on animal behaviour, and the capability of the animal species to adapt to human pressure. In this context, the reduction in human activities during COVID-19 lockdowns, which has been particularly severe in some Countries as Italy, constitutes an unprecedented semi-experimental condition to examine the responsiveness of animals to a dramatic alteration of human pressure, namely the “Anthropause”. We investigated this aspect in an anthropized area of Italian Alps, with the specific aim to analyse the adaptive response of three mammal species, namely roe deer (Capreolus capreolus), red deer (Cervus elaphus) and European badger (Meles meles) to the variation in functional disturbance that occurred during the Anthropause. We performed our assessment in a peri-urban area of the Eastern Alps (Valle di Cembra, Trentino Alto-Adige), focusing on the patterns of visits by these three species to eight artificial foraging sites, which have been monitored by means of camera traps both during the lockdown (9 March–4 May 2020) and in the same period in 2019, the latter being used as a baseline for our empirical evaluation of animal responsiveness to alteration of human pressure. We have used an artificial intelligence (AI) algorithm (YOLOv4), combined with manual observation, to analyse over 130000 pictures collected in 2019 and 2020. We have analysed the circadian pattern of visits to the feeding sites by means of circular statistics (daily trend), while we have used Generalized Additive Mixed Models (GAMMs) to investigate the trend of use of feeding sites by the three target species over the period of analysis (i.e., 9 March–4 May 2020 compared with 9 March–4 May 2019). We found that all the three species increased their number of visits to feeding sites in 2020 compared to 2019. We did not detect any temporal circadian alteration in the patterns of visits from 2019 to 2020, with badgers and red deer remaining strictly nocturnal, while roe deer exhibited the typical peaks of visits at dawn and dusk, with the rest of activity concentrated in nightly hours. Instead, the trend of visits to feeding sites over the examined period changed both for roe deer and badger, but not for red deer. While the pattern of visits to these anthropogenic resources was mainly dictated by seasonality in 2019, in 2020 we observed a clear link with the intensity of the lockdown, i.e., an increase of visits over the strict lockdown period, followed by a reduction when some mining activities occurring in the immediate surroundings restarted. The absence of a clear change in the circadian pattern of visits, i.e., without an increase in daytime visits during lockdown — often time reported by several unusual observations of wildlife in that period — suggests that the adaptation towards noctur nality in these species is likely a fixed behavioural trait, which a relatively short alteration of human disturbance has not been able to release. The response obtained in badger and roe deer relative to the trend during the observation period denotes the high plasticity of these species, which have increased the use of a resource linked to anthropogenic risk in the absence of cues of anthropic functional disturbance (for example noises quarries or forestry works). Taken together, these results confirm what has already been observed in numerous other studies, namely that the response of wildlife to the so called Anthropause is articulated and complex, depending on the characteristics of the species and the time scale at which the analysis is performed
The wolf is back! Non‐consumptive effects of the return of a large carnivore on the use of supplementary feeding sites by roe deer
Get PDFUnderstanding how prey species tradeoff predation risk and resource acquisition is particularly important for advancing our knowledge of predator–prey relationships. We investigated this by studying the use of concentrated anthropogenic resources, namely supplementary feeding sites, by roe deer Capreolus capreolus before and after grey wolf Canis lupus recolonisation in an area of the eastern Italian Alps. We used camera traps to monitor roe deer visits to feeding sites, where ad libitum food was provided, before and after wolf recolonisation, in winter and spring, to control for seasonal effects. First, we compared the daily cycle of visits using circular statistics. We then used generalised linear mixed models to assess roe deer, duration of visits, and tendency to congregate at feeding sites as a function of wolf presence and season. Roe deer became more diurnal after wolf recolonisation, particularly in winter, while in spring they tended to concentrate their visits around dusk and dawn. Roe deer visits to feeding sites decreased from winter to spring, but only after wolf recolonisation, while their duration was shorter in spring when wolves were absent than in any other period. Roe deer grouping at feeding sites decreased from winter to spring, especially after wolf recolonisation. These results show that roe deer have changed their resource use behaviour following wolf recolonisation, adopting a range of behavioural tactics that could mitigate predation risk, while maintaining resource acquisition when more profitable. The increase in diurnality may reduce the temporal overlap with wolves' predominantly nocturnal activity; access to the resource-rich, but fairly exposed sites mainly occurred during the most limiting season, or with solitary visits. We call for further research to understand whether other unmeasured processes contribute to shaping the observed patterns, such as demographic decline and fine-scale behavioural adjustments (e.g. increased vigilance
Proactive and reactive movement behaviours shape the antipredator sequence in a large herbivore
Get PDFBackground: Prey species can display antipredator movement behaviours to reduce predation risk, including proactive responses to chronic or predictable risk, and reactive responses to acute or unpredictable risk. Thus, at any given time, prey movement choice may reflect a trade-off between proaction and reaction. In previous studies, proaction and reaction have generally been considered separately, which neglects their potentially simultaneous influence on animal movement decisions and overall space use. Methods: In this study, we analysed how proaction and reaction interact to shape the movements of GPS-collared red deer (Cervus elaphus) in response to hunting by humans. Using an exhaustive inventory of red deer hunting events and very high-resolution canopy cover density (LiDAR), we combined movement metric (displacement and path length) models and integrated step selection functions to investigate antipredator movement responses to lethal risk on various spatiotemporal scales, considering a dynamic landscape of risk. Results: Our results show that red deer either proactively avoided areas of chronic risk, or they selected canopy cover where and when risk was predictably high. However, when risk was encountered anyway, canopy cover was no longer selected, but only modulated a reactive response along a remain-to-leave continuum. This reaction was even more evident when the environment was unfamiliar, underlining the importance of memory in such reaction patterns. Conclusions: We describe how proaction and reaction fuse in an antipredator sequence of interconnected movement decisions in a large herbivore, and discuss how this result may help disentangle the ecological consequences of behavioural responses to predation. Finally, we lay the foundations for further investigations into the origins of similarities and differences between proactive and reactive movement response
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
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