The spatial ecology of red deer under different land use and management scenarios: Protected areas, mixed farms and fenced hunting estates

Spatiotemporal dynamics of Ixodes ricinus abundance in northern Spain

Ixodes ricinus is the most medically relevant tick species in Europe because it transmits the pathogens that cause Lyme borreliosis and tick-borne encephalitis. Northern Spain represents the southernmost margin of its main European range and has the highest rate of Lyme borreliosis hospitalisations in the country. Currently, the environmental determinants of the spatiotemporal patterns of I. ricinus abundance remain unknown in this region and these may differ from drivers in highly favourable areas for the species in Europe. Therefore, our study aimed to understand the main factors modulating questing I. ricinus population dynamics to map abundance patterns in northern Spain. From 2012 to 2014, monthly/fortnightly samplings were conducted at 13 sites in two regions of northern Spain to estimate spatiotemporal variation in I. ricinus questing abundance. Local abundance of I. ricinus was modelled in relation to variation in local biotic and abiotic environmental conditions by constructing generalised linear mixed models with a zero-inflated negative binomial distribution for overdispersed data. The different developmental stages of I. ricinus were most active at different times of the year. Adults and nymphs showed a peak of abundance in spring, while questing larvae were more frequent in summer. The main determinants affecting the spatiotemporal abundance of the different stages were related to humidity and temperature. For adults and larvae, summer seemed to be the most influential period for their abundance, while for nymphs, winter conditions and those of the preceding months seemed to be determining factors. The highest abundances of nymphs and adults were predicted for the regions of northern Spain with the highest rate of Lyme borreliosis hospitalisations. Our models could be the basis on which to build more accurate predictive models to identify the spatiotemporal windows of greatest potential interaction between animals/humans and I. ricinus that may lead to the transmission of I. ricinus-borne pathogens.

Animal Exposure Model for Mapping Crimean-Congo Hemorrhagic Fever Virus Emergence Risk

To estimate the determinants of spatial variation in Crimean-Congo hemorrhagic fever virus (CCHFV) transmission and to create a risk map as a preventive public health tool, we designed a survey of small domestic ruminants in Andalusia, Spain. To assess CCHFV exposure spatial distribution, we analyzed serum from 2,440 sheep and goats by using a double-antigen ELISA and modeled exposure probability with environmental predictors by using generalized linear mixed models. CCHFV antibodies detected in 84 samples confirmed low CCHFV prevalence in small domestic ruminants in the region. The best-fitted statistical model indicated that the most significant predictors of virus exposure risk were cattle/horse density and the normalized difference vegetation index. Model validation showed 99.7% specificity and 10.2% sensitivity for identifying CCHFV circulation areas. To map CCHFV exposure risk, we projected the model at a 1 × 1-km spatial resolution. Our study provides insight into CCHFV ecology that is useful for preventing virus transmission.

Mapping the risk of exposure to Crimean-Congo haemorrhagic fever virus in the Iberian Peninsula using Eurasian wild boar (Sus scrofa) as a model

Crimean-Congo haemorrhagic fever (CCHF) virus (CCHFV) is a tick-borne zoonotic pathogen that can cause a lethal haemorrhagic disease in humans. Although the virus appears to be endemically established in the Iberian Peninsula, CCHF is an emerging disease in Spain. Clinical signs of CCHFV infection are mainly manifested in humans, but the virus replicates in several animal species. Understanding the determinants of CCHFV exposure risk from animal models is essential to predicting high-risk exposure hotspots for public health action. With this objective in mind, we designed a cross-sectional study of Eurasian wild boar (Sus scrofa) in Spain and Portugal. The study analysed 5,291 sera collected between 2006 and 2022 from 90 wild boar populations with a specific double-antigen ELISA to estimate CCHFV serum prevalence and identify the main determinants of exposure probability. To do so, we statistically modelled exposure risk with host- and environment-related predictors and spatially projected it at a 10 × 10 km square resolution at the scale of the Iberian Peninsula to map foci of infection risk. Fifty-seven (63.3 %) of the 90 populations had at least one seropositive animal, with seroprevalence ranging from 0.0 to 88.2 %. Anti-CCHFV antibodies were found in 1,026 of 5,291 wild boar (19.4 %; 95 % confidence interval: 18.3-20.5 %), with highest exposure rates in southwestern Iberia. The most relevant predictors of virus exposure risk were wild boar abundance, local rainfall regime, shrub cover, winter air temperature and soil temperature variation. The spatial projection of the best-fit model identified high-risk foci as occurring in most of western and southwestern Iberia and identified recently confirmed risk foci in eastern Spain. The results of the study demonstrate that serological surveys of CCHFV vector hosts are a powerful, robust and highly informative tool for public health authorities to take action to prevent human cases of CCHF in enzootic and emergency settings.

Environmental filtering drives the assembly of mammal communities in a heterogeneous Mediterranean region

Agricultural expansion and intensification are major drivers of global change. Quantifying the importance of different processes governing the assembly of local communities in agroecosystems is essential to guide the conservation effort allocated to enhancing habitat connectivity, improving habitat quality or managing species interactions. We used multiple detection methods to record the occurrence of medium-sized and large-sized mammals in three managed landscapes of a heterogeneous Mediterranean region. Then we used a joint species distribution model to evaluate the relative influence of dispersal limitation, environmental filtering, and interspecific interactions on the local assembly of mammal communities in 4-km² plots. The partitioning of the explained variation in species occurrence was attributed on average 99% to environmental filters and 1% to dispersal filters. No role was attributed to biotic filters, in agreement with the scarce support for strong competition or other negative interactions found after a literature review. Four principal environmental factors explained on average 63% of variance in species occurrence and operated mainly at the landscape scale. The amount of shrub cover in the neighboring landscape was the most influential factor favoring mammal occurrence and accounted for nearly one-third of the total variance. The proportion of intensively managed croplands and proxies of human activity within landscape samples limited mammal presence. At the microhabitat scale (~80 m² plots) the mean percentage area deprived of woody vegetation also had a negative effect. Functional traits such as body mass or social behavior accounted for a substantial fraction of the variation attributed to environmental factors. We concluded that multiscale environmental filtering governed local community assembly, whereas the role of dispersal limitation and interspecific interactions was negligible. Our results suggest that further removal of shrubland, the expansion of intensive agriculture, and the increase of human activity are expected to result in species losses. The fact that community integrity responds to a single type of ecological process simplifies practical recommendations. Management strategies should focus on the conservation and restoration of shrubland, adopting alternatives to intensive schemes of agricultural production, and minimizing recreational and other human activities in remnant natural habitats within agroecosystems or mosaic landscapes.

Antimicrobial resistance in commensal Staphylococcus aureus from wild ungulates is driven by agricultural land cover and livestock farming

Staphylococcus aureus is a human pathobiont (i.e., a commensal microorganism that is potentially pathogenic under certain conditions), a nosocomial pathogen and a leading cause of morbidity and mortality in humans. S. aureus is also a commensal and pathogen of companion animals and livestock. The dissemination of antimicrobial resistant (AMR) S. aureus, particularly methicillin-resistant (MRSA), has been associated to its ability for establishing new reservoirs, but limited attention has been devoted to the role of the environment. To fill this gap, we aimed to characterize animal carrier status, AMR phenotypes, predominant clonal lineages and their relationship with clinical and food-chain settings, as well as to find predictors of AMR occurrence. Nasal swabs (n = 254) from wild boar (n = 177), red deer (n = 54) and fallow deer (n = 23) hunted in Portugal, during the season 2019/2020, yielded an overall carrier proportion of 35.8%, ranging from 53.7% for red deer and 32.2% for wild boar to 21.7% for fallow deer. MRSA from wild boar and phenotypically linezolid-resistant S. aureus from wild boar and red deer were isolated, indicating that resistance to antimicrobials restricted to clinical practice also occurs in wildlife. The most prevalent genotypes were t11502/ST2678 (29.6%) and t12939/ST2678 (9.4%), previously reported in wild boar from Spain. Clonal lineages reported in humans and livestock, like CC1, CC5 or CC8 (19.1%) and ST425, CC133 or CC398 (23.5%), respectively, were also found. The sequence type ST544, previously restricted to humans, is described in wildlife for the first time. We also identified that land use (agricultural land cover), human driven disturbance (swine abundance) and host-related factors (sex) determine resistance occurrence. These findings suggest that antibiotics used in clinical settings, agriculture and livestock farming, spill over to wildlife, leading to AMR emergence, with potential biological, ecological, and human health effects. This work is one of the most comprehensive surveys in Europe of S. aureus occurrence and determinants among widely distributed wild ungulates.

Survey of Culicoides-borne Bluetongue and Schmallenberg viruses at the wildlife-livestock interface in Doñana National Park (Spain)

A cross-sectional study was carried out to assess the circulation of bluetongue virus (BTV) and Schmallenberg virus (SBV) within the wild and domestic ungulate host community in Doñana National Park (southwestern Spain). A total of 440 animals, including 138 cattle, 102 red deer (Cervus elaphus), 101 fallow deer (Dama dama) and 99 wild boar (Sus scrofa) were sampled in 2015 during the seasonal peak of Culicoides spp. (summer-autumn). Serum and spleen samples were analysed to detect exposure (using commercial blocking ELISAs) and infection (by RT-PCR), respectively, to BTV and SBV. Cattle were not tested by BTV-bELISA because all were previously vaccinated against BTV serotypes 1 and 4. High BTV seroprevalences were found in red deer (97.0%) and fallow deer (64.7%). Antibodies against SBV were detected in 37.0% of cattle, 16.8% of red deer, 23.5% of fallow deer and 2.0% of wild boar. Thirty-eight of the 203 deer (18.7%; 17 red deer and 21 fallow deer) were co-exposed to both viral agents. BTV-4 RNA was confirmed in four red deer and two fallow deer. SBV RNA was found in two fallow deer. Co-infections were not detected. Our results indicate high exposure, widespread distribution, and active circulation of BTV and SBV in the ruminant community in the study area. We provide additional evidence for the potential role of wild cervids as reservoirs of these Culicoides-borne viruses in two different epidemiological scenarios: with vaccination (BTV) and without vaccination (SBV) of sympatric livestock. This study highlights the importance of wildlife surveillance, particularly of cervid species, for the proper execution of control programmes of Culicoides-borne diseases in extensively reared livestock. This article is protected by copyright. All rights reserved.

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.

Characterization and management of interaction risks between livestock and wild ungulates on outdoor pig farms in Spain

Background

To control the transmission of relevant shared diseases, such as animal tuberculosis (TB) and African swine fever (ASF), it is essential to reduce the risk of interaction between livestock and wild ungulates. In Eastern and Central Europe, the current spread of ASF virus affecting wild boar and domestic pigs (especially those raised outdoors and/or in backyards) has devastated the pig sector in affected regions and is seriously threatening other exporting countries. Here, we evaluated the risk of wildlife-livestock interactions on 45 outdoor pig farms in Spain, the second largest pork producer in the EU and then proposed biosecurity-related actions. An integrated, systematic wildlife risk mitigation protocol based on interviews, questionnaires and field audits was developed and applied on each farm.

Results

Most of the interaction risk points were associated with water sources (84.2%; 701/832), mainly springs and ponds, which accounted for almost all the specific points with high or very high risk scores. The risk of interaction at feeding points (6.9%; 57/832) and those associated with facilities for livestock and/or game management (8.9%; 74/832) were rated as low and very low risk, respectively. Wild boar were present and hunted on 69% of the farms. Supplementary feeding for wild ungulate species (mainly wild boar) was provided on almost half (48.9%; 22/45) the surveyed farms. Risk mitigation actions were categorised to target water access, waterers, food, other livestock species, grazing, wildlife, and offal disposal. Of the total number of actions (n = 2016), 82.7% were identified as priority actions while 17.3% represented alternative options which were identified less cost-effective. On average, 37.1 (median: 32; range 14–113) action proposals per study farm were made and 2.0 (median: 1; range 0–4) per risk point. The mean estimated cost of implementing the proposed priority actions was 14,780 €/farm (25.7 €/hectare and 799.4 €/risk point).

Conclusions

This study expands the knowledge of interaction risks between domestic pigs and wild ungulates in outdoor pig farming systems and highlights the importance of considering local risks and management practices when designing and prioritising adapted wildlife risk mitigation and biosecurity actions. This practical and feasible protocol developed for Mediterranean ecosystems is easily transferable to professionals and can be adapted to extensive (outdoor) production or epidemiological systems in other European regions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40813-021-00246-7.

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.