Intact but empty forests? Patterns of hunting-induced mammal defaunation in the tropics

Tropical forests are increasingly degraded by industrial logging, urbanization, agriculture, and infrastructure, with only 20% of the remaining area considered intact. However, this figure does not include other, more cryptic but pervasive forms of degradation, such as overhunting. Here, we quantified and mapped the spatial patterns of mammal defaunation in the tropics using a database of 3,281 mammal abundance declines from local hunting studies. We simultaneously accounted for population abundance declines and the probability of local extirpation of a population as a function of several predictors related to human accessibility to remote areas and species’ vulnerability to hunting. We estimated an average abundance decline of 13% across all tropical mammal species, with medium-sized species being reduced by >27% and large mammals by >40%. Mammal populations are predicted to be partially defaunated (i.e., declines of 10%–100%) in ca. 50% of the pantropical forest area (14 million km2), with large declines (>70%) in West Africa. According to our projections, 52% of the intact forests (IFs) and 62% of the wilderness areas (WAs) are partially devoid of large mammals, and hunting may affect mammal populations in 20% of protected areas (PAs) in the tropics, particularly in West and Central Africa and Southeast Asia. The pervasive effects of overhunting on tropical mammal populations may have profound ramifications for ecosystem functioning and the livelihoods of wild-meat-dependent communities, and underscore that forest coverage alone is not necessarily indicative of ecosystem intactness. We call for a systematic consideration of hunting effects in (large-scale) biodiversity assessments for more representative estimates of human-induced biodiversity loss

Piercing and tatooing in high school students of Veneto region: prevalence and perception of infectious releated risk

Introduction. Body piercing (P) and tattoo (T) is a growing social phenomenon over recent years. Nowadays in Italy little is known about the prevalence, the attitude, the medical and social conse- quences of these activities. The purpose of this study is to examine the prevalence distribution and the attitude towards P and T and the perception of the risk for infections, in a sample of high school students living in the four Provinces of the Veneto Region (Italy). Methods. An anonymous, self administrate multiple-choice questionnaire about piercing and tattoo practices was dis- tributed during the 2009-2010 academic year to a sample of randomly extracted grades to obtain information about socio- demographic characteristics, family educational level, personal attitude, prevalence and perception of the importance of the sanitary, technical and artistic competence of the operator. Results. The correctly compiled questionnaires were 2712 (95.4%). Males and females were respectively 46.2% and 53.8% (mean age 17 ± 1.7 years). The 20.2% and the 6.4% of all the students had already experienced respectively P and T and resulted ?very interested? the 46.7% to P and the 57.4% to T. Esthetical motivations are the main ones referred to use body art. The most part of interviewed subjects (81.6%) think that it is possible to have an infection, but only about 50% of stu- dents reported to know specific information about transmission of HIV, Viral Hepatitis and skin infections. The parents? educa- tional levels do not influence the perception of the risk of infec- tion. The majority of interviewed subjects (88.0%) prefers to undergo body art practices in a qualified center. Only the 30% of students recur to a medical help to solve problem of infection. Discussion. The piercing and tattoo prevalence rate in our study (P: 20.2% and T:6.4%) resulted similar to other Italian ones (range reported: P: 20.3-35.1%, T: 4.8-8.6%), showing an increasing trend with age. Since a high rate of interviewed students referred a substan- tial ignorance about the risk of transmission of body art related infectious diseases, it is suitable to promote as soon as possible among the youth educational interventions and counseling

Mechanistic insights into the role of large carnivores for ecosystem structure and functioning

Large carnivores can exert top–down effects in ecosystems, but the size of these effects are largely unknown. Empirical investigation on the importance of large carnivores for ecosystem structure and functioning presents a number of challenges due to the large spatio-temporal scale and the complexity of such dynamics. Here, we applied a mechanistic global ecosystem model to investigate the influence of large-carnivore removal from undisturbed ecosystems. First, we simulated large-carnivore removal on the global scale to inspect the geographic pattern of top–down control and to disentangle the functional role of large carnivores in top–down control in different environmental contexts. Second, we conducted four small-scale ecosystem simulation experiments to understand direct and indirect changes in food-web structure under different environmental conditions. We found that the removal of top–down control exerted by large carnivores (> 21 kg) can trigger large trophic cascades, leading to an overall decrease in autotroph biomass globally. Furthermore, the loss of large carnivores resulted in an increase of mesopredators. The magnitude of these changes was positively related to primary productivity (NPP), in line with the ‘exploitation ecosystem hypothesis’. In addition, we found that seasonality in NPP dampened the magnitude of change following the removal of large carnivores. Our results reinforce the idea that large carnivores play a fundamental role in shaping ecosystems, and further declines and extinctions can trigger substantial ecosystem responses. Our findings also support previous studies suggesting that natural ecosystem dynamics have been severely modified and are still changing as a result of the widespread decline and extinction of large carnivores

Procurement and ex-situ perfusion of isolated slaughterhouse-derived livers as a model of donors after circulatory death

Ex-situ machine perfusion (MP) techniques are increasingly used in clinical settings, especially on grafts derived from donors after cardiac death (DCD). However, comprehension of biological effects elicited during MP are largely unknown and a substantial number of animal studies are presently focused on this topic. The aim of the present study was to describe a model of DCD based on ex-situ perfusion of liver grafts derived from animals dedicated to food production. Procurement took place within a slaughterhouse facility. A clinically fashioned closed circuit normothermic MP (NMP) was built up. Autologous blood-enriched perfusion fluid was adopted. Perfusate and tissue samples were collected to asses NMP functionality. Grafts were classified as transplantable (LT-G) or not (n-LT) according to clinical criteria, while histopathological analysis was used to confirm graft viability. After cold storage, the liver grafts were connected to the NMP. During the rewarming phase, temperature and flows were progressively increased to reach target values. At the end of NMP, 4 grafts were classified as LT-G and 3 nLT-G. Histology confirmed absence of major damage in LT-G, while diffuse necrosis appeared in nLT-G. Interestingly, in nLT-G an early impairment of hepatocyte respiratory chain, leading to cell necrosis and graft non-viability, was documented for the first time. These parameters, together with indocyanine-green dye and citrate clearance could contribute to graft evaluation in clinical settings. In conclusion, this model provides a promising and reproducible method to replace dedicated experimental animals in DCD and MP research, in line with the 3Rs principles

Population level consequences of facultatively cooperative behaviour in a stochastic environment

1. The social environment in which individuals live affects their fitness and in turn population dynamics as a whole. Birds with facultative cooperative breeding can live in social groups with dominants, subordinate helpers that assist with the breeding of others, and subordinate non-helpers. Helping behaviour benefits dominants through increased reproductive rates and reduced extrinsic mortality, such that cooperative breeding might have evolved in response to unpredictable, harsh conditions affecting reproduction and/or survival of the dominants. Additionally, there may be different costs and benefits to both helpers and non-helpers, depending on the time-scale. For example, early-life costs might be compensated by later-life benefits. These differential effects are rarely analysed in the same study. 2. We examined whether helping behaviour affects population persistence in a stochastic environment and whether there are direct fitness consequences of different life-history tactics adopted by helpers and non-helpers. 3. We parameterised a matrix population model describing the population dynamics of female Seychelles warblers Acrocephalus sechellensis, birds that display facultative cooperative breeding. The stochastic density-dependent model is defined by a (st)age structure that includes life-history differences between helpers and non-helpers and thus can estimate the demographic mechanisms of direct benefits of helping behaviour. 4. We found that population dynamics are strongly influenced by stochastic variation in the reproductive rates of the dominants, that helping behaviour promotes population persistence and that there are only early-life differences in the direct fitness of helpers and non-helpers. 5. Through a matrix population model, we captured multiple demographic rates simultaneously and analysed their relative importance in determining population dynamics of these cooperative breeders. Disentangling early-life versus lifetime effects of individual tactics sheds new light on the costs and benefits of helping behaviour. For example, the finding that helpers and non-helpers have similar lifetime reproductive outputs and that differences in reproductive values between the two life-history tactics arise only in early life suggests that overall, helpers and non-helpers have a similar balance of costs and benefits when analysing direct benefits. We recommend analysing the consequence of different life-history tactics, during both early life and over the lifetime, as analyses of these different time frames may produce conflicting results

Novel risk calculator performance in athletes with arrhythmogenic right ventricular cardiomyopathy

Background: Disease progression and ventricular arrhythmias (VAs) in arrhythmogenic right ventricular cardiomyopathy (ARVC) are correlated with physical exercise, and clinical detraining and avoidance of competitive sport practice are suggested for ARVC patients. An algorithm assessing primary arrhythmic risk in ARVC patients was recently developed by Cadrin-Tourigny et al. Data regarding its transferability to athletes are lacking. Objective: The purpose of this study was to assess the reliability of the Cadrin-Tourigny risk prediction algorithm in a cohort of athletes with ARVC and to describe the impact of clinical detraining on disease progression. Methods: All athletes undergoing clinical detraining after ARVC diagnosis at our institution were enrolled. Baseline and follow-up clinical characteristics and data on VA events occurring during follow-up were collected. The Cadrin-Tourigny algorithm was used to calculate the a priori predicted VA risk, which was compared with the observed outcomes. Results: Twenty-five athletes (age 36.1 \ub1 14.0 years; 80% male) with definite ARVC who were undergoing clinical detraining were enrolled. Over median (interquartile range) follow-up of 5.3 (3.2\u20136.6) years, a reduction in premature ventricular complex (PVC) burden (P = .001) was assessed, and 10 VA events (40%) were recorded. The a priori algorithm-predicted risk seemed to fit with the observed cohort arrhythmic risk [mean observed\u2013predicted risk difference over 5 years \u20130.85% (interquartile range \u20134.8% to +3.1%); P = .85]. At 1-year follow-up, 11 patients (44%) had an improved stress ECG response, and no significant changes in right ventricular ejection fraction were observed. Conclusion: Clinical detraining is associated with PVC burden reduction in athletes with ARVC. The novel risk prediction algorithm does not seem to require any correction for its application to ARVC athletes

Structural equation modeling reveals determinants of fitness in a cooperatively breeding bird

Even in well-studied organisms, it is often challenging to uncover the social and environmental determinants of fitness. Typically, fitness is determined by a variety of factors that act in concert, thus forming complex networks of causal relationships. Moreover, even strong correlations between social and environmental conditions and fitness components may not be indicative of direct causal links, as the measured variables may be driven by unmeasured (or unmeasurable) causal factors. Standard statistical approaches, like multiple regression analyses, are not suited for disentangling such complex causal relationships. Here, we apply structural equation modeling (SEM), a technique that is specifically designed to reveal causal relationships between variables, and which also allows to include hypothetical causal factors. Therefore, SEM seems ideally suited for comparing alternative hypotheses on how fitness differences arise from differences in social and environmental factors. We apply SEM to a rich data set collected in a long-term study on the Seychelles warbler (Acrocephalus sechellensis), a bird species with facultatively cooperative breeding and a high rate of extra-group paternity. Our analysis reveals that the presence of helpers has a positive effect on the reproductive output of both female and male breeders. In contrast, per capita food availability does not affect reproductive output. Our analysis does not confirm earlier suggestions on other species that the presence of helpers has a negative effect on the reproductive output of male breeders. As such, both female and male breeders should tolerate helpers in their territories, irrespective of food availability

Structural equation modeling reveals determinants of fitness in a cooperatively breeding bird

Even in well-studied organisms, it is often challenging to uncover the social and environmental determinants of fitness. Typically, fitness is determined by a variety of factors that act in concert, thus forming complex networks of causal relationships. Moreover, even strong correlations between social and environmental conditions and fitness components may not be indicative of direct causal links, as the measured variables may be driven by unmeasured (or unmeasurable) causal factors. Standard statistical approaches, like multiple regression analyses, are not suited for disentangling such complex causal relationships. Here, we apply structural equation modeling (SEM), a technique that is specifically designed to reveal causal relationships between variables, and which also allows to include hypothetical causal factors. Therefore, SEM seems ideally suited for comparing alternative hypotheses on how fitness differences arise from differences in social and environmental factors. We apply SEM to a rich data set collected in a long-term study on the Seychelles warbler (Acrocephalus sechellensis), a bird species with facultatively cooperative breeding and a high rate of extra-group paternity. Our analysis reveals that the presence of helpers has a positive effect on the reproductive output of both female and male breeders. In contrast, per capita food availability does not affect reproductive output. Our analysis does not confirm earlier suggestions on other species that the presence of helpers has a negative effect on the reproductive output of male breeders. As such, both female and male breeders should tolerate helpers in their territories, irrespective of food availability