After a long period of human persecution that led it to extinction in most of its distribution range, the wolf is undergoing a fast recovery. Despite being described as an elusive species only living ...in remote areas, wolves are recently occupying also human‐dominated landscapes, increasing the frequency of direct contacts with humans. Nevertheless, it is unclear whether this situation is only caused by a numerical increase or partially facilitated by a higher tolerance of wolves with respect to human proximity. We focused on a European region offering an abundant, widespread and long‐term monitored wolf population to analyse wolf pack distribution and its relationship with human presence across areas recolonized across four different time periods (1972, 1996, 2005 and 2016). Throughout areas recolonized during different periods, wolves were initially located in mountains and hills, occupying plains only in the recent past. Although they consistently tended to be located as far as possible from urban settlements, especially from those with over 5000 inhabitants, in 2016, 70% of packs included at least one urban settlement within the expected home range. Moreover, the distance kept by wolves from the nearest urban settlement was more constrained in areas of recent recolonization (2005 and 2016) and in the mountainous altitudinal range, likely due to a reduced availability of territories. We showed that wolves tend to keep as far away as possible from humans, but they can also permanently occupy human‐dominated landscapes to cope with the lower availability of space induced by their remarkably successful recolonization. Our results shed light on an upcoming scenario for the conservation of large carnivores.
Abbreviated summary for graphical TOC: Wolves are increasingly occupying anthropogenic landscapes, producing novel scenarios for their conservation in the near future. We analysed the temporal patterns of the spatial distribution of wolf packs with respect to urban settlements, focusing on an abundant wolf population monitored between 1974 and 2016. Wolves kept as far away as possible from humans during the whole period, but they were forced to permanently occupy human‐dominated landscapes to cope with the lower availability of territories.
Is horn length crucial for Alpine chamois? Grignolio, S.; Brivio, F.; Chirichella, R. ...
Journal of zoology (1987),
August 2022, 2022-08-00, 20220801, Letnik:
317, Številka:
4
Journal Article
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Animal weapons are one of the most studied morphological traits, particularly in Artiodactyla. Since in polygynous species males with larger weapons tend to be more successful in gaining access to ...females, researchers have traditionally focused on horn size. However, in species with limited horn size, weapon size has been assumed to have a reduced or null effect on life history traits. We examined the effect of intrinsic and extrinsic factors on the length of the second and third segments of Alpine chamois horns (Rupicapra rupicapra) in a population living in a poor environment. Our aim was to test how environmental conditions affected weapon growth and whether compensatory growth occurred. We showed that horn length was isometric to body size, although male horns grew more quickly. Ecological factors such as snow and forage availability affected weapon length, though mildly. No sign of compensatory growth was detected. We inferred that chamois mainly use horns as armament in intrasexual interactions. However, horn length was not a key element since horn growth remained isometric, at least under suboptimal ecological conditions. In species without extreme weapons, the handicap caused by longer horns is likely not compensated by an increase in individual fitness.
Studies on species with weapons that are not extreme have analysed intrinsic and extrinsic factors affecting weapon growth. However, they have often failed to provide full understanding of the actual benefits associated with larger weapons in these species. In Alpine chamois, we found that some environmental factors significantly affected horn length, however the magnitude of such influence was negligible from biological point of view, the actual weapon size being only mildly influenced. The linearity of the relationship between the horns and body weight and the absence of compensatory growth indicate that these biometric measures are isometric during the first years of life. Our findings, on a monomorphic species without extreme weapons, suggest focusing not only on weapon size but also on their use, shape and the different drivers affecting their ontogenesis.
Among ungulates, capital breeding males, especially in highly dimorphic species, support higher reproductive costs than females. Roe deer, a relatively monomorphic species, is defined as an ‘income ...breeder’, using a concurrent intake of energy from forage to pay for a reproductive attempt. In a Northern Apennines (Arezzo province, Tuscany, Central Italy) population, we detected sexual dimorphism in adult roe deer according to average body mass (males 11% heavier than females), mandible size (male mandibles are 2% longer than female ones), and tooth measurements (first lower molar 10% higher and mandible cheek teeth row 4% longer in males than in females, providing males with a larger surface for chewing). In our study, body mass and body condition of roe deer males decreased with increasing tooth wear as in females. However, males started losing weight at a lower tooth wear level than females; after losing about 15% (~3.2 kg) of body mass they had greater probability of death than females. For low‐dimorphic species like roe deer, these findings raise new considerations about the role of sexual dimorphism in feed intake efficiency.
In a Northern Apennines (Italy) population, we detected sexual dimorphism in adult roe deer according to body mass, mandible size, and tooth measurements. Moreover, we evaluated the role of tooth wear in causing senescence. Body mass and body condition of roe deer males decreased with increasing tooth wear. However, once they reached tooth wear values half of those of females, they were no longer able to support the intake of a necessary amount of energy, suggesting that chewing capacity in males has been compromised. Males also wear down a larger proportion of teeth than females over their lifetime; after losing about 15% of body mass, they have a greater probability of death than females. These data open up new questions for low‐dimorphic species like roe deer, that is, exploring sexual dimorphism in relation to feed intake efficiency among different populations.
The wild boar (Sus scrofa) is an ungulate of major management concern, often controlled only by indiscriminate, recreational hunting, which represents its main cause of death. Several studies have ...dealt with the effects of hunting on wild boar populations, pointing out controversial changes in spatial behavior and habitat use related to it. However, little information on the relationship between spatial behavior, habitat use and hunting mortality is available. In this study, 105 wild boars were monitored by means of radio‐tracking. Their cause of death was assessed, thus confirming the major role of hunting. For 89 of them, spatial behavior and habitat use as well as social class were related to hunting mortality. Spatial behavior, expressed as home range size, average daily distance among fixes and familiarity with the hunting area, resulted in having no strong effect on hunting mortality. Conversely, the relationship between the wild boar and the habitat, expressed in the proportion of forests in the home range, landscape complexity and habitat diversity, had a major role in predicting hunting mortality. In particular, the best model including social class and refuges pointed out a positive effect of landscape complexity on hunting mortality, while animals having a higher proportion of forests in their home range (assessed when this did not overlap the protected area) were less likely to be culled. Adult males and subadults of both sexes were more liable to be hunted than family groups. On the whole, behavioral and ecological differences in hunting vulnerability should be taken into account in management plans in order to optimize population management.
We investigated the cause of death of 105 wild boars monitored by means of radio‐tracking. For 89 of them, spatial behavior, habitat use and social class were related to hunting mortality. Spatial behavior did not significantly affect hunting mortality, which however was affected by the proportion of forests in the home range, landscape complexity and habitat diversity. Moreover, adult males and subadults of both sexes were more liable to be hunted than family groups. Accordingly, behavioral and ecological differences in hunting vulnerability should be taken into account in population management plans. Photo credit: Andrea Castellini.
Abstract
Human‐dominated environments are growing worldwide, forcing animals to adapt to new conditions characterized by increased risks and/or anthropogenic resources availability. While numerous ...studies have compared behavioural patterns of rural and urban populations, little is known about plastic behavioural responses to temporal variations in human presence. We modelled the behaviour‐specific resource selection of 15 wild boars (
Sus scrofa
) GPS‐tracked between 2017 and 2019 in a tourist area in Italy characterized by high seasonal variability of human presence. By means of activity sensor data, we differentiated between two behavioural states with different ecological needs: resting (safe shelter) and activity (food intake). We investigated the variability of selection/avoidance of infrastructures and beaches, across seasons and behavioural states. We expected human‐built landscape features to be avoided for resting and selected for activity, with a strength proportional to the seasonal level of human presence. Instead, wild boars selected locations near infrastructures and away from beaches, both for resting and while being active. We showed that the similarity of behavioural patterns exhibited during the resting and active phases was accountable to the wild boar activities being spatially constrained by the proximity with their previous resting location. As expected, the selection for infrastructure proximity and avoidance of beaches peaked in summer (maximum human presence) and was negligible in winter (least human presence), showing that a variable human presence elicits intra‐individual plastic responses in animal populations. Our results suggest the behavioural flexibility of wild boars as a key factor enabling them to rapidly colonize human‐dominated environments.
Protected areas are often blamed for offering refuge to pest species populations, giving rise to the so-called “reserve effect”. Nevertheless, this major conservation side effect has seldom been ...investigated or verified on a local scale. Along the borders of two protected areas of different size, we modelled wild boar individual likelihood of being either inside or outside the protected areas throughout the year, considering their activity rhythms and resource availability. No evidence of reserve effect was found in the small protected area, yet the percentage of wild boar moving across the border was smaller in the large one. Moreover, although wild boar use of the large protected area resulted to increase in autumn, we showed that this was not the consequence of hunting avoidance. Our results clearly highlighted the importance to verify reserve effect on a local scale with studies based on detailed information on animal spatial behaviour and environmental variables.
•Larger reserves can host a higher portion of pest species populations.•Wild boar increases the use of protected areas during nightlight in autumn.•Pest species can move into reserves for reasons different from hunting avoidance.•Data on resource use and activity patterns are needed to understand reserve effect.
The European wild boar is an important game species, subjected to local extinctions and translocations in the past, and currently enormously and worryingly expanding in some areas where management is ...urgently required. Understanding the relative roles of ancient and recent events in shaping the genetic structure of this species is therefore not only an interesting scientific issue, but it represents also the basis for addressing future management strategies. In addition, several pig breeds descend from the European wild boar, but the geographical location of the domestication area(s) and the possible introgression of pig genomes into wild populations are still open questions. Here, we analysed the genetic variation in different wild boar populations in Europe. Ten polymorphic microsatellites were typed in 252 wild boars and the mtDNA control region was sequenced in a subset of 145 individuals. Some samples from different pig breeds were also analysed. Our results, which were obtained considering also 612 published mtDNA sequences, suggest that (i) most populations are similarly differentiated, but the major discontinuity is found along the Alps; (ii) except for the Italian populations, European wild boars show the signature of a postglacial demographic expansion; (iii) Italian populations seem to preserve a high proportion of preglaciation diversity; (iv) the demographic decline which occurred in some areas in the last few centuries did not produce a noticeable reduction of genetic variation; (v) signs of human-mediated gene flow among populations are weak, although in some regions the effects of translocations are detectable and a low degree of pig introgression can be identified; (vi) the hypothesis of an independent domestication centre in Italy is not supported by our data, which in turn confirm that Central European wild boar might have represented an important source for domestic breeds. We can therefore conclude that recent human activities had a limited effect on the wild boar genetic structure. It follows that areas with high variation and differentiation represent natural reservoirs of genetic diversity to be protected avoiding translocations. In this context controlling some populations by hunting is not expected to affect significantly genetic variation in this species.
Game species are often manipulated by human beings, whose activities can deeply affect their genetic make-up and population structure. We focused on a geographically isolated wild boar population ...(Sardinia, Italy), which is classified, together with the Corsican population, as a separate subspecies (Sus scrofa meridionalis). Two hundred and ten wild boars collected across Sardinia were analysed with a set of 10 microsatellites and compared with 296 reference genotypes from continental wild populations and to a sample of domestic pigs. The Sardinian population showed remarkable diversity and a high proportion of private alleles, and strongly deviated from the equilibrium. A Bayesian cluster analysis of only the Sardinian sample revealed a partition into five subpopulations. However, two different Bayesian approaches to the assignment of individuals, accounting for different possible source populations, produced consistent results and proved the admixed nature of the Sardinian population. Indeed, introgressive hybridization with boars from multiple sources (Italian peninsula, central Europe, domestic stocks) was detected, although poor evidence of crossbreeding with free-ranging domestic pigs was unexpectedly found. After excluding individuals who carried exotic genes, the population re-entered Hardy-Weinberg proportions and a clear population structure with three subpopulations emerged. Therefore, the inclusion of introgressed animals in the Bayesian analysis implied an overestimation of the number of clusters. Nonetheless, two of them were consistent between analyses and corresponded to highly pure stocks, located, respectively, in north-west and south-west Sardinia. This work shows the critical importance of including adequate reference samples when studying the genetic structure of managed wild populations.
Mandibles of 2161 juvenile roe deer (8–10 months; 1176 females and 985 males) were studied to check for dental anomalies. The sample was legally shot during the annual harvest ...(1st January–15th March) of the hunting seasons 2013–2015 in the Arezzo province (Central Italy). The frequency of anomalies was 0.32% (
n
= 7), confirming that anomalies are uncommon in roe deer dentition. All individuals had only one type of dental anomaly. The teeth of the incisor arcade seldom showed anomalies (10%) in comparison to premolars (20%) and molars (70%). In more than half of juveniles with anomalies, the length of the posterior section of the mandible was shorter than the population average (from − 8 to − 20%), unlike the length of the medio-anterior section. Some dental anomalies seem to affect the growth of the posterior section of the mandible, which occurs mostly during the first year of life, rather than the growth of the medio-anterior section, which occurs mostly in utero. Due to the complex relationship between mandible growth and dental anomalies and their low frequency, further data are needed to deepen the possible influence of anomalies on growth pattern.
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