Trading fear for food in the Anthropocene: How ungulates cope with human disturbance in a multi-use, suburban ecosystem

Navigating discreetly: Spatial ecology of urban wild boar in Bordeaux City's landscape of fear, France

An exemplary urban adapter, the wild boar (Sus scrofa) has successfully colonized urban ecological niches worldwide. Improvement of strategies for optimal management of urban wild boar need to gather more empirical evidence of their spatial ecology. This study is based on GPS tracking and capture-mark-recapture (CMR) of 10 and 59 wild boar, respectively, captured in Bordeaux Metropolis (France). It shows that wild boar have become urban dwellers, with intra-urban home ranges varying from 1.3 to 64.6 km2 (MCP 100 %) and from 0.5 to 9.6 km2 (KDE 95 %), depending on urban conditions. CMR results confirm the low propensity to move away from urban areas (with a mean distance of 2 km between capture and recapture sites), despite a relatively low one-year survival rate since capture (47.5 %), primarily attributable to removal efforts. Wild boar strongly depended on urban woods, mostly during daytime resting, and highly frequented urban meadows during night foraging. Their use of urban agricultural areas was minimal, but they were mostly monitored following corn and grape harvests. Wild boar mitigated the risk associated with close proximity to humans by: a nocturnal activity (72.2 % of active locations registered from sunset to sunrise), which could also be partially attributed to their sensitivity to heat; a strong use of covered habitats, especially during daytime resting and when close to buildings and roads; and a low mobility during night-time foraging (1974 m average daily distance travelled). Moreover, we demonstrate high inter- and intra-individual variability in the spatio-temporal behaviour of urban wild boar. Finally, we discuss the gap between these results and the narratives surrounding the spatial ecology of urban wild boar. Our results not only confirm the species' ability to adapt to urban environments, but also highlight their behavioural flexibility, underscoring the relevance of significant changes in representations and management activities to mitigate human-urban wild boar conflicts.

A highly variable habitat selection in moose across diel and seasonal scales

PURPOSE

Habitat selection in animals is a hierarchal process that operates across multiple temporal and spatial scales, adapting to changes in environmental conditions, human disturbances, and predation risks. Despite its significance, previous research often oversimplifies temporal dynamics by categorizing them into broad seasonal and diel patterns, overlooking the continuous nature of temporal variability and habitat specificity.

METHODS

We investigated the temporal patterns in habitat selection of moose (Alces alces) in highly heterogenous landscapes at the southwestern edge of their European range using step-selection functions. Utilizing over 700,000 GPS locations from 34 adult moose, we aimed to assess seasonal and diel patterns in their selectivity for both natural and human-related habitats.

RESULTS

Our findings revealed significant overall temporal variation in moose habitat selection at both seasonal and diel scales. Moose selectivity toward different habitats showed low repeatability over time, with 35% of cases displaying negative correlation between selectivity in different time windows. Diel changes were more pronounced, showing 5.6-fold difference in cumulative selectivity, compared to 1.4-fold difference in seasonal dynamics. Notably, moose exhibited lower selectivity during nighttime hours throughout the year compared to daytime hours. The study also highlighted distinct habitat selection patterns across different habitat types: natural habitats (deciduous forests, coniferous forests, wetlands) exhibited pronounced seasonal variation, while anthropogenic habitats (grasslands, arable land, roads and settlements) showed more diel variability. Moose generally avoided human-related habitats during daytime hours, but their preferences during nighttime varied depending on the habitat type and time of year.

CONCLUSION

This research advances our understanding of the complex temporal patterns in habitat selection by large herbivores and underscores the importance of considering temporal dynamics in habitat selection modelling.

Large mammal behavioral defenses induced by the cues of human predation

Large mammals respond to human hunting via proactive and reactive responses, which can induce subsequent nonconsumptive effects (NCEs). Thus, there is evidence that large mammals exhibit considerable behavioral plasticity in response to human hunting risk. Currently, however, it is unclear which cues of human hunting large mammals may be responding to. We conducted a literature review to quantify the large mammal behavioral responses induced by the cues of human hunting. We detected 106 studies published between 1978 and 2022 of which 34 (32%) included at least one measure of cue, typically visual (n = 26 of 106, 25%) or auditory (n = 11 of 106, 10%). Space use (n = 37 of 106, 35%) and flight (n = 31 of 106, 29%) were the most common behavioral responses studied. Among the 34 studies that assessed at least one cue, six (18%) measured large mammal behavioral responses in relation to proxies of human hunting (e.g. hunting site or season). Only 14% (n = 15 of 106) of the studies quantified an NCE associated with an animal's response to human hunting. Moreover, the association between cues measured and antipredator behaviors is unclear due to a consistent lack of controls. Thus, while human hunting can shape animal populations via consumptive effects, the cues triggering these responses are poorly understood. There hence remains a need to link cues, responses, NCEs, and the dynamics of large mammal populations. Human activities can then be adjusted accordingly to prevent both overexploitation and unintended NCEs in animal populations.

When and where? Day-night alterations in wild boar space use captured by a generalized additive mixed model

Wild boar (Sus scrofa), an abundant species across Europe, is often subjected to management in agro-ecosystems in order to control population size, or to scare them away from agricultural fields to safeguard crop yields. Wild boar management can benefit from a better understanding on changes in its space use across the diel cycle (i.e., diel space use) in relation to variable hunting pressures or other factors. Here, we estimate wild boar diel space use in an agro-ecosystem in central Belgium during four consecutive "growing seasons" (i.e., April-September). To achieve this, we fit generalized additive mixed models (GAMMs) to camera trap data of wild boar aggregated over 1-h periods. Our results reveal that wild boar are predominantly nocturnal in all of the hunting management zones in Meerdaal, with activity peaks around sunrise and sunset. Hunting events in our study area tend to take place around sunrise and sunset, while non-lethal human activities occur during sunlight hours. Our GAMM reveals that wild boar use different areas throughout the diel cycle. During the day, wild boar utilized areas in the centre of the forest, possibly to avoid human activities during daytime. During the night, they foraged near (or in) agricultural fields. A post hoc comparison of space use maps of wild boar in Meerdaal revealed that their diurnal and nocturnal space use were uncorrelated. We did not find sufficient evidence to prove that wild boar spatiotemporally avoid hunters. Finally, our work reveals the potential of GAMMs to model variation in space across 24-h periods from camera trap data, an application that will be useful to address a range of ecological questions. However, to test the robustness of this approach we advise that it should be compared against telemetry-based methods to derive diel space use.

Temporal niche partitioning among sympatric wild and domestic ungulates between warm and cold seasons

The coexistence of sympatric species with similar ecological niches has been a central issue in ecology. Clarifying the daily activity patterns of sympatric wild ungulates can help understand their temporal niche differentiation and the mechanisms of coexistence, providing information for their conservation. The Baotianman National Nature Reserve in northern China is rich in wild ungulates, but little is known about the daily activity patterns of wild ungulates in the area, making it difficult to develop effective conservation strategies. We studied five representative wild ungulates (i.e. forest musk deer, Chinese goral, Reeve's muntjac, Siberian roe deer, and wild boar) of the region using camera-trapping data, focusing on the seasonal daily activity patterns and effects of seasonal grazing of domestic sheep, to reveal their coexistence based on temporal ecological niche differentiation. Comparative analyses of the seasonal daily activity showed that forest musk deer exhibited a single-peak activity in the warm season. Other ungulates exhibited multipeak activity. All five ungulates differed significantly in daily activity patterns. Notably, wild boar and Reeve's muntjac showed high overlap coefficients between the cold and warm seasons. In both cold and warm seasons, the five wild ungulates and domestic sheep displayed low overlap in their daily activity rhythms potentially indicating temporal ecological niche differentiation. The results suggest that temporal isolation might be a strategy for wild ungulates to avoid domestic sheep and reduce interspecific competition, and that temporal ecological niche differentiation potentially promoted the coexistence among the studied sympatric ungulates. This understanding may provide new insights for the development of targeted conservation strategies.

Impacts of zoning and landscape structure on the relative abundance of wild boar assessed through a Bayesian N-mixture model

Increasing human-wild boar interactions have led to damage to agricultural crops, traffic collisions and disease transmissions. Dividing natural areas in zones with differential hunting pressure is one of the currently adopted management strategies. However, the effectiveness of this approach is under debate. Hence, there is a need to better understand how to mitigate negative human-wild boar interactions effectively. Camera traps are cost-efficient, and non-invasive tools to monitor animal populations. N-mixture models can reliably estimate spatial variation in relative abundances when animals are imperfectly detected and/or cannot be individually identified. Thus, they are useful tools to infer the impacts of several factors on the land-use intensity of wild boar, based on camera trap data. In a nature area in central Belgium, we compare "summer" (April-September) land-use intensity of wild boar from 2018 until 2021 between three zones: a hunting free core zone, a winter hunting zone where hunting only takes place between November and March, and a year-round hunting zone. The latter is also close to the forest edge, agricultural crops and settlements. We compare spatial abundance models that capture these zone effects, or attractive effects of croplands, repulsive effects of hunting and repulsive effects of non-lethal human disturbances. We reveal between zone differences in wild boar land-use intensities across all summers. Additionally, we find that non-lethal human disturbance and croplands also explain variation in wild boar land-use intensity, but do not find negative associations with hunting locations. Our results suggest that the effects of zoning on wild boar land-use patterns are relevant in medium-sized natural areas. Moreover, we identify the need to install additional cameras outside of the managed area in order to assess the impacts of hunting in combination with non-lethal human activities on wild boar to mitigate negative human-wild boar interactions in the future.

Land cover preferences and spatiotemporal associations of ungulates within a Scottish mammal community

In the degraded and modified environment of the Scottish Highlands, novel ungulate communities have arisen following local extinctions, reintroductions, and the introduction of non-native species. An understanding of the dynamics and interactions within these unique mammal communities is important as many of these mammals represent keystone species with disproportionate impacts on the environment. Using a camera trap survey, we investigated land cover preferences and spatiotemporal interactions within a Scottish ungulate community: the sika deer (Cervus nippon), the roe deer (Capreolus capreolus), the red deer (Cervus elaphus), and the wild boar (Sus scrofa). We used generalised linear models to assess land cover preferences and the effect of human disturbance; spatiotemporal interactions were characterised using time interval modelling. We found that sika deer and roe deer preferred coniferous plantations and grasslands, with sika deer additionally preferring woodland. For red deer, we found a slight preference for wetland over woodland; however, the explained variance was low. Finally, wild boar preferred grassland and woodland and avoided coniferous plantations, heathland, and shrubland. Contrary to our expectations, we found no evidence that human disturbance negatively impacted ungulates' distributions, potentially because ungulates temporally avoid humans or because dense vegetation cover mitigates the impacts of humans on their distributions. Furthermore, we detected a spatiotemporal association between sika deer and roe deer. Although the underlying cause of this is unknown, we hypothesise that interactions such as grazing facilitation or an anti-predator response to culling could be driving this pattern. Our work provides a preliminary analysis of the dynamics occurring within a novel ungulate community and also highlights current knowledge gaps in our understanding of the underlying mechanisms dictating the observed spatiotemporal associations.

Simulation-based assessment of the performance of hierarchical abundance estimators for camera trap surveys of unmarked species

Knowledge on animal abundances is essential in ecology, but is complicated by low detectability of many species. This has led to a widespread use of hierarchical models (HMs) for species abundance, which are also commonly applied in the context of nature areas studied by camera traps (CTs). However, the best choice among these models is unclear, particularly based on how they perform in the face of complicating features of realistic populations, including: movements relative to sites, multiple detections of unmarked individuals within a single survey, and low detectability. We conducted a simulation-based comparison of three HMs (Royle-Nichols, binomial N-mixture and Poisson N-mixture model) by generating groups of unmarked individuals moving according to a bivariate Ornstein-Uhlenbeck process, monitored by CTs. Under a range of simulated scenarios, none of the HMs consistently yielded accurate abundances. Yet, the Poisson N-mixture model performed well when animals did move across sites, despite accidental double counting of individuals. Absolute abundances were better captured by Royle-Nichols and Poisson N-mixture models, while a binomial N-mixture model better estimated the actual number of individuals that used a site. The best performance of all HMs was observed when estimating relative trends in abundance, which were captured with similar accuracy across these models.

Impact of green space connectivity on urban tick presence, density and Borrelia infected ticks in different habitats and seasons in three cities in southern England

Understanding the effects of local habitat and wider landscape connectivity factors on tick presence, nymph density and Borrelia species (spp.) prevalence in the tick population is important for identifying the public health risk from Lyme borreliosis. This multi-city study collected data in three southern England cities (Bath, Bristol, and Southampton) during spring, summer, and autumn in 2017. Focusing specifically on urban green space used for recreation which were clearly in urbanised areas, 72 locations were sampled. Additionally, geospatial datasets on urban green space coverage within 250 m and 1 km of sampling points, as well as distance to woodland were incorporated into statistical models. Distance to woodland was negatively associated with tick presence and nymph density, particularly during spring and summer. Furthermore, we observed an interaction effect between habitat and season for tick presence and nymph density, with woodland habitat having greater tick presence and nymph density during spring. Borrelia spp. infected Ixodes ricinus were found in woodland, woodland edge and under canopy habitats in Bath and Southampton. Overall Borrelia spp. prevalence in nymphs was 2.8%, similar to wider UK studies assessing prevalence in Ixodes ricinus in rural areas. Bird-related Borrelia genospecies dominated across sites, suggesting bird reservoir hosts may be important in urban green space settings for feeding and infecting ticks. Whilst overall density of infected nymphs across the three cities was low (0.03 per 100 m²), risk should be further investigated by incorporating data on tick bites acquired in urban settings, and subsequent Lyme borreliosis transmission.

Intensive hunting changes human-wildlife relationships

Wildlife alter their behaviors in a trade-off between consuming food and fear of becoming food themselves. The risk allocation hypothesis posits that variation in the scale, intensity and longevity of predation threats can influence the magnitude of antipredator behavioral responses. Hunting by humans represents a threat thought to be perceived by wildlife similar to how they perceive a top predator, although hunting intensity and duration varys widely around the world. Here we evaluate the effects of hunting pressure on wildlife by comparing how two communities of mammals under different management schemes differ in their relative abundance and response to humans. Using camera traps to survey wildlife across disturbance levels (yards, farms, forests) in similar landscapes in southern Germany and southeastern USA, we tested the prediction of the risk allocation hypothesis: that the higher intensity and longevity of hunting in Germany (year round vs 3 months, 4x higher harvest/km²/year) would reduce relative abundance of hunted species and result in a larger fear-based response to humans (i.e., more spatial and temporal avoidance). We further evaluated how changes in animal abundance and behavior would result in potential changes to ecological impacts (i.e., herbivory and predation). We found that hunted species were relatively less abundant in Germany and less associated with humans on the landscape (i.e., yards and urban areas), but did not avoid humans temporally in hunted areas while hunted species in the USA showed the opposite pattern. These results are consistent with the risk allocation hypothesis where we would expect more spatial avoidance in response to threats of longer duration (i.e., year-round hunting in Germany vs. 3-month duration in USA) and less spatial avoidance but more temporal avoidance for threats of shorter duration. The expected ecological impacts of mammals in all three habitats were quite different between countries, most strikingly due to the decreases in the relative abundance of hunted species in Germany, particularly deer, with no proportional increase in unhunted species, resulting in American yards facing the potential for 25x more herbivory than German yards. Our results suggest that the duration and intensity of managed hunting can have strong and predictable effects on animal abundance and behavior, with the potential for corresponding changes in the ecological impacts of wildlife. Hunting can be an effective tool for reducing wildlife conflict due to overabundance but may require more intensive harvest than is seen in much of North America.

Wild Boar Survives in a Landscape That Prohibits Anthropogenic Persecution

Geopolitical borderlands are politically sensitive areas and biodiversity hotspots, strictly controlled by the government and military. How to ensure political security, while protecting the biodiversity in borderlands is a problem for ecologists and governments. In this study, the nest site selection of the wild boar Sus scrofa was a case study in the Sino-Russia borderland to understand the survival strategy of wild life under anthropogenic pressure. We investigated (a) how the spatial distribution of anthropogenic pressure and wild boar nests in the borderland and (b) how anthropogenic pressure and the border influence on the wild boars’ nest site selection. The Getis-Ord Gi* analysis was used to analyze the distribution patterns of wild boar nest sites and anthropogenic pressures in the borderland, the Structural Equation Models was used to explore the influence of border, roads, settlements, agricultural land, grassland and anthropogenic pressure on wild boars’ nest site selection. The results indicated that wild boar nest sites are close to the border, roads and agricultural land and away from settlements and grassland. Regardless of the combination of anthropogenic pressure, wild boars make the most advantageous choice and prefer to be closer to the borderland. We speculated that military control played a vital role in borderlands for animal protection under anthropogenic pressure. Wild boars benefit from the prohibition of anthropogenic persecution due to military control. Compared with existing measures, we suggest a different protection/wildlife management strategy, what we need to do may be to prohibit anthropogenic persecution rather than perform other human interventions to protect animals. However, for a species with trouble potential, we need to base our conservation strategies on the recovery of top predators, and play the community control role of top predators to avoid the occurrence of trouble.

Seasonal resource selection of an arboreal habitat specialist in a human-dominated landscape: a case study using red panda

Human dominated landscapes provide heterogeneous wildlife habitat. Conservation of habitat specialists, like red pandas Ailurus fulgens, inhabiting such landscapes is challenging. Therefore information on resource use across spatial and temporal scales could enable informed-decision making with better conservation outcomes. We aimed to examine the effect of geo-physical, vegetation, and disturbance variables on fine-scale habitat selection of red pandas in one such landscape. We equipped 10 red pandas with GPS collars in eastern Nepal in 2019 and monitored them for one year. Our analysis was based on a generalized-linear-mixed model. We found the combined effect of geo-physical, vegetation and disturbance variables resulted in differences in resource selection of red pandas and that the degree of response to these variables varied across seasons. Human disturbances, especially road and cattle herding activities, affected habitat utilization throughout the year whereas other variables were important only during restricted periods. For instance, geo-physical variables were influential in the premating and cub-rearing seasons while vegetation variables were important in all seasons other than premating. Red pandas selected steeper slopes with high solar insolation in the premating season while they occupied elevated areas and preferred specific aspects in the cub-rearing season. Furthermore, the utilized areas had tall bamboo in the birthing and cub-rearing seasons while they also preferred diverse tree species and high shrub cover in the latter. Our study demonstrates the significance of season-specific management, suggests the importance of specific types of vegetation during biologically crucial periods, and emphasizes the necessity to minimize disturbances throughout the year.

Differences in wild boar spatial behaviour among land uses and management scenarios in Mediterranean ecosystems

The ubiquitous wild boar is causing diverse and growing conflicts of socio-ecological and economic relevance worldwide. For that reason, knowledge of its spatial ecology is crucial to designing effective management programmes. But this knowledge is scarce in Mediterranean areas with mixed land uses. We describe the spatial ecology and habitat selection of 41 adult wild boar monitored using GPS collars and analyse the effects of sex and the period (food shortage period, hunting season and food abundance period) under different land uses (protected areas, mixed farms and fenced hunting estates). The spatial ecology of wild boar was characterised by marked temporality, mediated by sex and the land uses in the area. The activity (ACT), daily range (DR) and home range (HR) were higher for males than females, and in mixed farms versus fenced hunting estates, while the lowest values were obtained in protected areas. These effects were more marked for ACT and DR (movement) than HR. The selection of scrublands and avoidance of woodlands was observed where drive hunt events occur (mixed farms and fenced estates), but not in the protected areas. The differences in the requirements, reproductive behaviour and, interestingly, response to disturbance according to sex may explain this dissimilar behaviour. Disturbance originated higher movement rates and the selection of sheltering land cover as a refuge during the hunting season. This information is useful for designing species monitoring and management programmes; including both preventive and reactive actions in response to events such as outbreaks of African swine fever and agricultural damage produced by wild boar in Europe.

Effect of disturbances and habitat fragmentation on an arboreal habitat specialist mammal using GPS telemetry: a case of the red panda

CONTEXT

Habitat specialists residing in human-modified landscapes are likely to be more vulnerable to disturbance because of a functional reliance on very particular habitat features. However, there have been few studies designed to specifically address that issue.

OBJECTIVES

This study aimed to explore how the red panda, an iconic endangered habitat specialist, behaves when faced with disturbances and habitat fragmentation. In particular, we attempted to examine the effect of anthropogenic disturbances and fragmentation on home-range size, activity patterns, and recursion.

METHODS

Using GPS telemetry we monitored 10 red pandas and documented disturbances using camera trapping for one year in eastern Nepal. We performed spatial analysis, analysed activity patterns and evaluated the effect of habitat fragmentation and disturbances on home-range size and residence time using Linear Mixed Models.

RESULTS

Home-range size increased in areas with low availability of forest cover whilst home ranges were smaller in areas with a high road density. Red pandas spent more time in large habitat patches away from roads and cattle stations. Crossing rates suggested that roads acted as a barrier for movement across their habitat. Red pandas also partitioned their activity to minimize interactions with disturbances.

CONCLUSIONS

Red pandas seem to make a trade-off to co-exist in human-dominated landscapes which may have adverse long-term effects on their survival. This indicates that current patterns of habitat fragmentation and forest exploitation may be adversely affecting red panda conservation efforts and that landscape-scale effects should be considered when planning conservation actions.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10980-021-01357-w.

Managing African Swine Fever: Assessing the Potential of Camera Traps in Monitoring Wild Boar Occupancy Trends in Infected and Non-infected Zones, Using Spatio-Temporal Statistical Models

The recent spreading of African swine fever (ASF) over the Eurasian continent has been acknowledged as a serious economic threat for the pork industry. Consequently, an extensive body of research focuses on the epidemiology and control of ASF. Nevertheless, little information is available on the combined effect of ASF and ASF-related control measures on wild boar (Sus scrofa) population abundances. This is crucial information given the role of the remaining wild boar that act as an important reservoir of the disease. Given the high potential of camera traps as a non-invasive method for ungulate trend estimation, we assess the effectiveness of ASF control measures using a camera trap network. In this study, we focus on a major ASF outbreak in 2018-2020 in the South of Belgium. This outbreak elicited a strong management response, both in terms of fencing off a large infected zone as well as an intensive culling regime. We apply a Bayesian multi-season site-occupancy model to wild boar detection/non-detection data. Our results show that (1) occupancy rates at the onset of our monitoring period reflect the ASF infection status; (2) ASF-induced mortality and culling efforts jointly lead to decreased occupancy over time; and (3) the estimated mean total extinction rate ranges between 22.44 and 91.35%, depending on the ASF infection status. Together, these results confirm the effectiveness of ASF control measures implemented in Wallonia (Belgium), which has regained its disease-free status in December 2020, as well as the usefulness of a camera trap network to monitor these effects.

Habitat-Related Differences in Winter Presence and Spring–Summer Activity of Roe Deer in Warsaw

Preliminary research conducted in Warsaw in the 1970s and 2000s showed that roe deer (Capreolus capreolus) stayed in forest habitat and avoided anthropogenic areas. Activity and exploration patterns of animals are shaped by indices of anthropogenic disturbances, elevated in large cities. The aims of the study were (1) to compare the presence of roe deer in natural and anthropogenic habitats of Warsaw during three periods: 1976–1978, 2005–2008 and 2017–2021, based on snow tracking on transect routes (681.2 km in total), and (2) to describe the presence and activity of roe deer in relation to human disturbances in selected urban forests in its reproductive period (March–August), based on camera trap survey (2019–2020, 859 observations, 5317 trap-days in total). The number of tracks was higher in natural habitat during all three periods, with the highest value in 2017–2021 (9.85/km/24h). The peak of roe deer activity was recorded at dusk, and it changed with moon phases between spring and summer. Landscape connectivity and level of light pollution did not affect the activity pattern of roe deer. Our research showed that roe deer inhabiting urban areas avoided human presence by using well-covered habitats and being active in periods when the level of human disturbance was lower.