PurposeThis study aims to explore environmental factors associated with parasite infections in faecal samples collected from wild boar populations, by analysing the prevalence, intensity, and abundance of parasite communities across two Italian ecosystems: the alpine environment in the Orco Valley (Gran Paradiso National Park) and the Mediterranean lowland in the Maremma Regional Park.MethodsSeasonal faecal samples were collected from November 2023 to July 2025 along systematic transects in both study areas. Samples were analysed using the Mini-FLOTAC technique to quantify parasite eggs and (oo)cysts, and prevalence, intensity, and abundance were calculated. Environmental variables, including elevation, land use, temperature, precipitation, and season, were linked to each sample. Generalized linear models (GLMs) were fitted to evaluate the effects of environmental factors on parasite presence and abundance.ResultsParasite communities were dominated by Eimeria spp., gastrointestinal strongyles, and Metastrongylus spp., whereas other taxa (e.g., Balantioides coli, Capillaria spp., Cystoisospora sp.) were sporadic. Significant differences in intensity and/or abundance of dominant taxa were observed between the two areas. Models based on infection abundance, rather than presence, revealed environmental associations: Metastrongylus spp. abundance decreased with increasing elevation, possibly reflecting constraints on intermediate host availability; while gastrointestinal strongyles abundance was lower in open natural habitats, reflecting microclimatic influences on larval survival.ConclusionsThis study highlights associations between habitat characteristics and parasite community structure in wild boar populations, providing insights into the environmental factors potentially influencing parasite transmission across heterogeneous landscapes.

Sawfishes are highly threatened elasmobranchs, now locally extinct in many coastal areas worldwide. Global conservation efforts emphasize documenting historical shifts in species' distribution and range. In the Mediterranean Sea, these historical reconstructions suggested the past presence of two species, Pristis pristis and Pristis pectinata, thought extinct by the 1970s, revising prior assumptions on sawfish distribution. In this study, we evaluated whether any historical sawfish specimens housed in several European institutions and private collections might represent records from the Mediterranean Sea. We analysed 229 rostra, of which 28 were labelled as Mediterranean individuals. Most specimens lacked detailed taxonomic identification or reliable collection data. Using morphometrics and mitochondrial gene sequencing (partial COI and NADH2) we identified all rostra as belonging to four extant sawfish species: Pristis zijsron (104), Anoxypristis cuspidata (52), P. pristis (47), and P. pectinata (26). Specimens labelled as Mediterranean belonged to P. zijsron (9), A. cuspidata (8), P. pristis (6), and P. pectinata (5). These findings demonstrate the effectiveness of an integrative framework combining molecular and morphometric analyses for reliable species' identification in historical sawfish specimens, providing a robust basis for re-evaluating historical diversity and biogeography even when collection metadata are incomplete or uncertain.

Elasmobranchs (sharks and rays) represent a critical component of marine ecosystems. However, they are experiencing global population declines, making effective monitoring essential for their management. Underwater stationary videos, such as those from Baited Remote Underwater Video Stations (BRUVS), are vital for understanding elasmobranch spatial ecology and abundance. However, processing these videos requires time-consuming manual analysis, which can delay conservation efforts. To address this challenge, we developed SharkTrack, a semi-automatic underwater video analysis software. SharkTrack uses Object Detection and Multi-Object Tracking models to automatically detect and track elasmobranchs, providing an annotation pipeline to manually classify elasmobranch species and compute species-specific MaxN (ssMaxN), the standard metric of relative abundance. When tested on BRUVS footage from locations unseen by the model during training, SharkTrack computed ssMaxN with 89% accuracy over 207 h of footage. The semi-automatic SharkTrack pipeline required only two minutes of human labour per hour of video, an estimated 95% reduction in manual analysis time compared to traditional methods. Additionally, we demonstrate the accuracy of SharkTrack across diverse marine ecosystems and elasmobranch species, a significant improvement over previous models, which were limited to specific species or locations. SharkTrack's application extends beyond BRUVS, facilitating the analysis of any underwater stationary video. By making video analysis faster and more accessible, SharkTrack enables research and conservation organizations to monitor elasmobranch populations more efficiently, thereby improving conservation efforts. To further support these goals, we provide public open-access to the SharkTrack software.

Predation is a key ecological interaction shaping prey populations through both consumptive and non-consumptive pathways, influencing prey behavior and eliciting antipredator responses. Vigilance is a fundamental antipredator strategy that may induce stress and motivational conflict in prey, potentially giving rise to displacement activities. Among these activities, self-grooming is a behavior widely recognised as an anxiety and stress-ameliorating response across many taxa. However, its role in wild ungulates remains poorly understood. We investigated the relationship between self-grooming, vigilance, and perceived predation risk in a wild, gregarious ungulate, the fallow deer, in an area recently recolonised by wolves. Using an extensive camera-trapping dataset, we quantified the relationship between vigilance and three indices of self-grooming (probability, frequency, and proportion), while testing the effects of age, sex, season, wolf and human visitation rates, habitat openness, and group size. Our results revealed a strong, direct relationship between vigilance rate and all three self-grooming indices. In contrast, group size, wolf detection rate, and season showed weak or inconsistent effects. Habitat openness was associated with reduced self‑grooming in some models for males, although only one of these models was weakly significant. Age and sex also weakly influenced self-grooming patterns: younger males groomed less frequently, while younger females groomed more frequently than adults. Overall, our findings provide the first evidence that self-grooming in fallow deer is closely linked to vigilance, supporting its interpretation as a vigilance-linked self-directed behavior. These results highlight the potential of self-grooming as a non-invasive behavioral indicator of perceived risk in wild ungulates, with important implications in predator-recolonised landscapes. Predators shape prey populations not only through killing but also through non-consumptive effects on behavior and physiology, a cost that is hard to quantify in free-ranging animals. This study identifies self-grooming, a widespread comfort behavior, as a vigilance-linked displacement activity in fallow deer living in an area recently recolonised by wolves. Using camera-trapping, we show that self-grooming closely tracks vigilance rate in both sexes, consistent with its role as a de-arousal response following a stressful, motivational conflict between feeding and scanning for danger. Notably, this relationship held regardless of group size or wolf detection rate, suggesting perceived predation risk acts on self-directed behavior primarily at the individual level rather than through group-mediated antipredator strategies. These findings support self-grooming as a practical, non-invasive behavioral indicator of perceived risk, with direct relevance for monitoring wildlife welfare in areas undergoing large carnivore recolonisation.

Body mass is one of the important ecological traits for indexing mammal phenotypic quality, determining individual survival and reproductive potential. Assessing the relative role of body mass determinants, such as weather, habitat, or population density, is crucial to predict individual and population responses to the environmental variations. We considered a widespread herbivore of temperate ecosystems, the roe deer Capreolus capreolus. We evaluated body mass responses of different sex/age classes to environmental variables, such as temperature, precipitation (considered only for fawns), habitat composition and heterogeneity (as Shannon index), and population density, throughout 15 years in a central-Italy area. Average temperature and precipitation in the previous spring-summer showed weak effects on fawns, suggesting that milder and wetter conditions during birth and weaning periods may influence the body mass. Shannon index had opposing effects on sexes: it impacted positively female body mass, and negatively male body mass in warmer months. Broadleaved woodlands were associated with higher body mass in fawns compared to agricultural land, probably because the latter is mostly bare during autumn–winter and does not provide abundant food resources. Population density was not a significant explanatory variable of body mass, probably as a consequence of the relatively high environmental quality of the study area. These findings highlight the role of habitat and weather in driving body mass differences and provide insights for individual responses to environmental variation in Mediterranean ecosystems. Results suggest that management actions should consider seasonal and sex-specific ecological needs, particularly to face the climate and habitat changes.

Herbivory may threaten forest conservation, depleting habitat quality in protected areas, yet effects of herbivore population densities on Mediterranean forests remain poorly understood. Holm oak Quercus ilex forests are the most widely-distributed in the Mediterranean, being carbon sinks and protected under the EU-directive, despite unfavourable status. We investigated how browsing pressure by introduced fallow deer Dama dama and native roe deer Capreolus capreolus affected habitat quality of Holm oak forests in protected areas. Typical plants' cover increased forest patch palatability to deer, escalating their browsing pressure. Thus, deer impact may target sentinel species of this habitat. However, only spatiotemporal increases in fallow deer densities boosted browsing at the community- and sentinel species-levels, depleting up to half of the browse responsible for plant regeneration when at moderate-high density. This result highlights stronger ecological impacts of introduced deer compared to their native counterparts. We found fallow deer inhabiting similar to 20 % EU-protected Holm-oak forests, which raises potential bioregion-wide threats to Mediterranean forest conservation. Precipitation did not dilute deer browsing via enhanced plant resprouting; therefore, reversing current Mediterranean aridification would benefit forests only if deer densities are mitigated. Fallow deer affected browsing at multiple spatial-scales, recommending coordinated management actions at the appropriate extent to reduce impact. Throughout our study, the decline in fallow deer density, possibly triggered by wolf Canis lupus recolonisation, resulted in browsing collapse, suggesting that top-down control by apex predators may entail forest restoration. Our findings contribute practical solutions to foster conservation of Mediterranean forests under browsing pressure, offering insights into ecosystem resilience.

Ongoing environmental changes are affecting behavioral responses of animal populations. Both warming temperatures and increased human disturbance may trigger adjustments in mammal activity patterns, for example, favoring activity switch to nighttime despite a greater risk of encountering nocturnal predators. Disentangling the relative roles of these stressors is critical for predicting the population-level consequences of environmental changes, yet the joint effect of multiple stressors is poorly understood. Here we investigated how ambient summer temperature, predators, and human presence influenced temporal responses in two herbivorous mammals (the roe deer Capreolus capreolus and the fallow deer Dama dama) across Mediterranean protected areas. By conducting intensive camera trapping (∼12,400 trapping days; 196 sites), we evaluated changes in daily activity level and nocturnality of deer species. Both herbivores reduced their daily activity with warmer temperatures, emphasizing the need to minimize thermoregulatory costs, yet only roe deer increased nocturnality following diel warming. Conversely, nocturnality of the more heat-tolerant fallow deer was only affected by wolf (Canis lupus) visitation rate, although weakly, suggesting that fallow deer traded off heat avoidance with predator avoidance. We found neither reductions in daily activity levels nor an increase in nocturnality in response to higher human visitation rate, possibly depending on our relatively undisturbed protected areas (i.e., areas with low human population density and sustainable levels of outdoor recreational activities) or the stronger effect of heat avoidance. Under the anticipated warming, species-specific consequences of these behavioral responses on population viability may be expected.

As wolves recolonise their historical range across Europe, ungulates face predation once more - but in landscapes profoundly altered by human activity. This shift raises crucial questions about their capacity to express adaptive antipredator behaviours. Using a quasi-experimental camera-trap design, we examined diel activity responses of ungulates along the ongoing wolf recolonisation in the south-eastern Alps. Red deer showed higher summer diurnality in sites with a longer history of wolf presence (7% increase over five years, on average) and progressively reduced nocturnality within sites as local wolf establishment advanced (5% decrease per year, on average), also heightening activity overlap with humans. This 'diel shield effect' disappeared when human hunting occurred. Roe deer and Alpine chamois did not exhibit significant diel activity shifts in relation to wolves, though both species responded to human disturbance, with roe deer adjusting activity to hunting (18% less diurnal, on average) and chamois reducing diurnality in areas of intense outdoor use (up to 38% difference in diurnality between undisturbed and highly disturbed areas). Red deer, too, were less diurnal (up to 27% difference) and more nocturnal (up to 37% difference) in such highly disturbed areas, as well as near human settlements (up to 42% difference in diurnality between remote areas and villages). Our findings show that wolf recovery can induce detectable diel activity shifts in large herbivores over relatively short timescales, yet responses depend on species biology and behavioural plasticity. Importantly, human risk and disturbance can offset or override these behavioural adjustments, potentially altering the ecosystemic effects of returning large carnivores.

Highly migratory sharks such as the shortfin mako (Isurus oxyrinchus) undertake extensive oceanic movements that cross ecological and political boundaries. This wide-ranging behavior increases their exposure to human impacts, primarily from fishing activities, as the species is frequently caught as bycatch in longline fisheries. Consequently, the shortfin mako is listed as Endangered globally and Critically Endangered in the Mediterranean Sea. Despite growing conservation concerns, knowledge of its population structure within the Mediterranean, and its genetic and ecological connectivity with the Atlantic Ocean, remains limited, hindering the development of effective management measures. We investigated the population structure and demographic history of shortfin mako across the Eastern Atlantic Ocean and Mediterranean Sea using double-digest restriction-site associated DNA (ddRADseq) sequencing on 66 individuals collected from six regions in the two areas. After sequence filtering, we retained 4349 neutral SNPs to assess population structure and demography. Our results indicated a single, genetically mixed population across the Eastern Atlantic-Mediterranean range, suggesting high connectivity and gene flow. Demographic analyses revealed a historically stable population size, although recent declines may not be detectable given the resolution of our genetic markers. While such connectivity may enhance resilience to localized pressures, it also implies that intense Mediterranean fishing could have population-wide consequences. These findings challenge the assumption of strong genetic isolation between basins but do not preclude demographic differentiation. Given that ICCAT currently treats the Mediterranean as a separate, data-poor stock, our results highlight the need for coordinated, basin-wide monitoring and management to safeguard this endangered species.

Preserving ecological complexity is a major goal of conservation biology. The recovery of large carnivores across Europe is expected to restore key interspecific interactions in trophic webs. Apex predators generally interfere with mesocarnivores, but facilitative interactions may occur through scavenging. Facilitative versus suppressive interactions may vary with increasing predator abundance, but information is scarce. We analysed changes in spatiotemporal and trophic behaviour of the red fox Vulpes vulpes in a prey-rich, Mediterranean protected area recently recolonized by the wolf Canis lupus, over six years from early recolonisation to the time of maximum predator expansion. Camera trapping records (n = 2619 wolf and n = 26195 fox detections) revealed a strong interspecific spatiotemporal association. Seasonal interspecific temporal overlap was high (Δ = 0.70–0.94, 0–1 scale) and increased throughout the study. A positive spatial association occurred between fox and wolf detection rates, and recurrent-event analyses supported attraction rather than avoidance. The occurrence of ungulates in the fox diet (n = 5150 analysed scats) peaked in the early recolonisation phase, but decreased with increasing wolf abundance. The wolf diet was dominated by wild ungulates and fox hair occurred in only 2 of the 2849 wolf scats. Our results emphasise complex interactions following wolf recovery, with increased foraging opportunities for foxes, and association prevailing over avoidance. However, benefits decreased with increasing wolf abundance, suggesting a lesser availability of leftovers for scavengers. Overall, our results indicate the restoration of the ecological role of apex predators in a prey-rich area, as well as the importance of prey availability to reduce competitive interactions.

Estimating wildlife density is challenging, and various methods have been developed to account for imperfect detection probability. In this study, we applied the Random encounter model (REM) to estimate the population density of the European mouflon Ovis aries on the Mediterranean island of Dugi Otok, Croatia. Our goal was to test if density estimations vary throughout the year in a closed population. We systematically placed 27 camera traps over an area of 35 km2 at the intersections of 1.5-km grid cells and kept them active for 12 months (March 2022 – March 2023). All REM parameters (i.e., average movement speed, angle and radius) were estimated from the camera trap data. To explore potential correlations of mean temperature and humidity with REM parameters, six data loggers were placed systematically. The mouflon was recorded at 21 locations in 1,227 independent events on 6,719 camera-trapping days. The lowest density was recorded in winter while the highest density was observed in autumn. Our findings indicate that mouflon changed activity patterns between July and October, with trap rates increasing during the rut, which led to a fluctuation in density estimates. Correlations of temperature and humidity with the trapping rate were statistically non-significant. The trend in density estimates from two-month data subsets suggests that the largest variation in density estimation occurred between June and November, coinciding with high temperatures and the rut season. This research suggests that density estimation using REM may be influenced by sampling bias driven by seasonal variation in animal behaviour. Consequently, integrating behavioural ecology into survey design is critical to an appropriate study planning and interpretation of results.

Predators can indirectly stimulate the development of anti-predator strategies in prey species. Within populations, these behavioral responses may vary according to sex and age classes of individuals, although the existing literature presents conflicting results. Using camera trapping, spatiotemporal responses to the wolf Canis lupus were assessed in relation to sex and age classes in two prey species, the fallow deer Dama dama and the roe deer Capreolus capreolus, within a Mediterranean area recently recolonized by this canid. In fallow deer, results suggest stronger temporal avoidance in females than in adult males, increasing their diurnal activity as the wolf detection rate increased and reducing their temporal overlap with the predator. In roe deer, the avoidance responses were less marked, but females, particularly during the warm period, exhibited different activity patterns compared to males. Smaller body size (fallow deer) and presence of offspring are expected to make females more vulnerable to predation, which would emphasize the perceived predation risk in these individuals, in turn promoting a stronger response to predators compared to males. Females of both species may adopt different activity patterns from males to minimize temporal overlap with the wolf and reduce the risk of direct predator encounters. By providing support to sexual differences in antipredator responses, our results provide a novel contribution to increasing knowledge on the indirect effects of recolonizing predators in human-dominated landscapes of Europe.

Resource partitioning between apex and subordinate carnivores is modulated by interspecific interactions, potentially affecting the ecology of all the species involved. Top predators may positively affect smaller species through increased carrion availability. However, for mesocarnivores, the risk of intraguild killing may outweigh the benefits of exploiting these resources, resulting in a complex tradeoff between attraction and avoidance. Despite its key importance, such a network of indirect interactions is particularly understudied in areas recently recolonized by large carnivores. We investigated wolfered fox spatiotemporal interactions using camera trapping in a protected alpine area that recently experienced wolf recolonization. We evaluated red fox temporal behaviour at the seasonal level, comparing sites with higher and lower wolf activity (higher wolf use site and lower wolf use site, respectively) and at a finer scale using a novel and recently developed approach: recurrent event analysis. Eventually, we evaluated the spatial variation of red fox detection rates in relation to wolf activity. Our results suggest a high temporal overlap between the two species in each season, with increased red fox activity in higher wolf use sites during spring. The fine-scale approach revealed a higher red fox observation rate shortly after a wolf detection. At the spatial scale, mixed models showed a positive association of wolf and fox detection rates in spring and marginally in winter. Overall, our results suggest spatiotemporal attraction rather than avoidance in alpine environments, thus emphasizing the wide behavioural plasticity of red foxes. The ultimate consequences of this mechanism on red fox fitness and population dynamics need to be further evaluated in the long term. (c) 2025 The Authors. Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Predators have the potential to affect prey ecology through both direct effects on population dynamics or indirect effects on behaviour, e.g., by triggering antipredator strategies. Direct effects of predation on single prey species may be limited in ecosystems hosting alternative prey, possibly being overwhelmed by indirect effects. The novel exposure to a predator would provide the opportunity to test for immediate prey responses, but information is scanty for areas recolonised by carnivores. We took advantage of the natural expansion of the wolf Canis lupus in a protected area of western Alps hosting five ungulate species to test the potential for direct versus indirect effects on the main prey, i.e., a widespread mountain herbivore (the Northern chamois Rupicapra rupicapra). After verifying the contribution of the latter to the diet of the former, we used a semi-experimental (before vs. after) approach by comparing chamois demography, elevation used and group size between two valleys with different recolonisation time (Site A: medium-term vs. Site B: short-term). Scat analyses (N = 335 samples) indicated that chamois were the staple in the wolf diet in both valleys. Analyses of counts throughout 21 years supported no direct effect of wolf on chamois abundance and survival. Following wolf recolonisation, female chamois (n = 3594 observations) in Site A were observed at average elevations 137 m higher compared to the former period, and a concurrent decrease of group size was reported; these effects were not detected in Site B. The same trend was not observed in temperature, precipitation or NDVI, providing no support to a weather- or resource-mediated uplift. Although direct/indirect effects of current changes in weather patterns on the observed uplift of chamois may not be ruled out, our results suggest antipredator behaviour as a main determinant of chamois upshift. Finally, we discuss the role of indirect versus direct short-term prey responses in complex ecosystems.

Sharks play a crucial role in the structure of marine ecosystems but are heavily threatened by overfishing globally. Due to their slow life history traits, even low fishing pressure can have an extreme influence on shark populations. The Mediterranean Sea, which has had historical overexploitation over the course of many centuries, is considered a hotspot for elasmobranchs. One particular species is the bluntnose sixgill shark, Hexanchus griseus , which has recently become more prominent in sightings and landings. Because of its deep range, H. griseus is difficult to study in situ so we used opportunistic data from sharkPulse, a crowd-sourcing platform that collects and organizes image-based shark occurrence records from all over the world, to better understand the abundance and distribution of H. griseus over the past decade. Additionally, we explored historical data to create a baseline of the species’ abundance starting from the late 1800s. We found that H. griseus underwent a quadratic-shaped change in their abundance where they started out as a rare catch, became increasingly more prominent in fisheries data, and now is declining like many other cartilaginous fishes in the Mediterranean Sea. This work is important because H. griseus is not yet threatened according to the IUCN so research is not heavily focused on this species but the decreasing trend we detected here is concerning while in line with the degree of exploitation of one of the most exploited regions of the world, as well as illustrative of a broader ecological process that will likely occur in many other large marine ecosystems worldwide. ### Competing Interest Statement The authors have declared no competing interest.

Environmental drivers can influence animal behaviour, affecting movement patterns and spatial dynamics with a cascading effect. Furthermore, most species adapt their behaviour to ecological factors, such as predation risk. In human-dominated landscapes, most medium-to-large terrestrial mammals are crepuscular or nocturnal, limiting their opportunities for other temporal changes. However, the role of nocturnal illumination and the lunar cycle in these spatiotemporal patterns remains understudied. We used camera trapping data, kernel density estimation, and generalized additive models to analyse the effects of the lunar cycle and moonlight on activity patterns of wolves Canis lupus and their ungulate prey in a Mediterranean area, accounting for cloudiness and habitat. Our results give no support to spatial avoidance by prey, and wolves were spatially synchronized with them. Additionally, we found no evidence of changes in animal activity modulated by moon brightness. Instead, we identified more refined mechanisms driving the relationships between wolves and their prey. Specifically, wolves seemed to exploit darker nights in areas more frequently used by their main prey (i.e. wild boar Sus scrofa and fallow deer Dama dama). Wild boar were more active during the brightest nights in the sites most used by the predator, whereas fallow deer were more active in the sites used in an intermediate way by the wolf and during nights with a middle nocturnal light intensity. Roe deer Capreolus capreolus were slightly more active during darker nights and in more concealed sites. These outcomes suggest that animal activity patterns reflect a trade-off between species-specific physiological features (e.g. poor nocturnal visual acuity in wild boars), the need for foraging, prey availability, vigilance, predation risk, human disturbances, and ambient light levels. Our results contribute to shed light on the underexplored effects of lunar illumination on predator and prey activities and relationships, particularly in ecosystems experiencing the return of apex predators.

Wild ungulates play crucial roles in food webs and their impacts can propagate across trophic levels. The recent spread of wild boar Sus scrofa is generating concerns worldwide for its potential negative impacts on biodiversity and human activities. Under particular conditions, its foraging activity through digging the topsoil (i.e., rooting) may affect endangered plant/animal species or agriculture. Identifying environmental drivers of rooting is crucial to address spatially-explicit measures to reduce negative impacts, as well as to clarify the often unclear link between rooting and wild boar density. We performed six-year intensive spring-summer surveys (763 sampling plots; 3343 surveys between 2019-2024) in 9 protected areas of central Italy encompassing heterogeneous habitats and a gradient in wild boar densities, to investigate spatial variations in wild boar rooting and relevant drivers. Strong support was obtained for a positive relationship between rooting, at both large (i.e., study area) and fine (i.e., sampling plot) scales, and wild boar density in the area. Results supported lower rooting with increasing landscape diversity. Rooting was affected by topography, being reduced by rock cover and terrain steepness, and increased with distance from the nearest road/railway. Models of fine-scale rooting variation were elaborated to develop high-resolution (10 x 10 m) predictive maps of rooting impact, providing a tool scalable to ecologically comparable areas. Findings support the control of wild boar population density and maintenance of high landscape diversity as measures to reduce wild boar impacts. Finally, the present study also supports that rooting can serve as an effective indicator of within- and between-area variations in wild boar density.

Interspecific interactions are important drivers of population dynamics and species distribution. These relationships can increase niche partitioning between sympatric species, which can differentiate space and time use or modify their feeding strategies. Roe deer Capreolus capreolus and red deer Cervus elaphus are two of the most widespread ungulate species in Europe and show spatial and dietary overlap. However, limited information is available on their interspecific relationships, especially in mountainous areas. In this study we used 5 years of camera trapping data collected in the Stelvio National Park (Central Italian Alps) to investigate spatial and temporal interactions between roe deer and red deer. Analyses were based on 2060 and 9030 roe deer and red deer detections, respectively, collected from July to September, from 2019 to 2023, using 50 camera traps randomly distributed over a 10,000-ha study area. Spatial interactions were assessed by fitting a single-season, single-species occupancy model to calculate the probability of roe deer detection and occupancy as a function of relative red deer abundance and site-specific environmental covariates. Temporal interactions were obtained by comparing the diel activity patterns of the two species. Results showed no significant effect of red deer relative abundance on the probability of presence of roe deer. Spatial analysis suggested a higher probability of roe deer presence in forested habitats, at lower elevations, and in areas with gentler slopes. Diel activity patterns of roe deer were consistent across sites with higher and lower red deer relative abundance, with moderate to high interspecific overlap, suggesting moderate temporal partitioning and no major support for temporal avoidance of the latter by the former. The high degree of overlap between the two species may be the result of area-specific ecological conditions, such as the widespread distribution of red deer during the summer period, as well as of the adoption of strategies that favor coexistence.

Theory predicts that high population density leads to more strongly connected spatial and social networks, but how local density drives individuals' positions within their networks is unclear. This gap reduces our ability to understand and predict density-dependent processes. Here we show that density drives greater network connectedness at the scale of individuals within wild animal populations. Across 36 datasets of spatial and social behaviour in >58,000 individual animals, spanning 30 species of fish, reptiles, birds, mammals and insects, 80% of systems exhibit strong positive relationships between local density and network centrality. However, >80% of relationships are nonlinear and 75% are shallower at higher values, indicating saturating trends that probably emerge as a result of demographic and behavioural processes that counteract density's effects. These are stronger and less saturating in spatial compared with social networks, as individuals become disproportionately spatially connected rather than socially connected at higher densities. Consequently, ecological processes that depend on spatial connections are probably more density dependent than those involving social interactions. These findings suggest fundamental scaling rules governing animal social dynamics, which could help to predict network structures in novel systems.