Impact Of Wild Boar Research Articles

Comparative Effects of Wild Boar (Sus scrofa) Rooting on the Chemical Properties of Soils in Natural and Post-Fire Environments of the Edough Forest Massif (Northeastern Algeria)

Wild boars use a wide range of habitats. Their invasive nature is gaining attention due to the complexity of its impact. The goal of this research is to analyze the impact of the wild boar on the chemical properties of soils in a natural and a post-fire forest in the Edough Forest Massif in Algeria. This study compares the impact of wild boar rooting on soil parameters to determine the functional role of the wild boar. The research was conducted during the winter of 2022. The study sites included a natural forest and a post-fire area. Rooting tracks were geolocated and soil samples were collected. The results show significant differences between rooted and control patches in the chemical parameters measured in the two environments. However, in the natural environment, significant differences were only noted for the calcium content and electrical conductivity. But in the post-fire environment, strong significant differences were observed for all measured parameters, suggesting that wild boars do not exert a noticeable soil homogenization effect on the soil properties. This research highlights the importance of understanding and managing the impact of wild boars in natural and post-fire forests on soil formation processes, the diversity of soil properties, and their magnitude.

Effects of wild boar grubbing on the soil nematode community subject to seasonal variation in a broad-leaved Korean pine forest in Northeast China

Soil disturbances caused by large animals impact soil biodiversity and potentially alter forest ecosystem functioning and productivity. However, most studies have focused on the effects of wild boar infestations on above-ground vegetation and soil physical and chemical properties. Little is known about the influence of wild boar grubbing on the soil faunal community within forested ecosystems. To address this knowledge gap, we conducted a long-term (10-year) exclosure experiment to investigate the responses of soil nematode communities to wild boar grubbing and seasonal variations in a broad-leaved Korean pine forest in Changbai Mountain, China. The results indicated that wild boar grubbing did not significantly impact soil nematode abundance, genus richness, diversity indices (Shannon-Wiener diversity index, Simpson index, and evenness index), and ecological indices (enrichment index, channel index, structural index, and basal index). However, we observed that grubbing reduced the relative abundance of plant parasites while increased that of bacterivores and the maturity index (MI), leading to changes in nematode community composition. Notably, the influence of grubbing was more pronounced in the spring than in the autumn. Although season itself did not significantly affect soil nematode genus richness and diversity indices, it did affect soil nematode relative abundance, bacterivores, omnivores-predators, plant parasites, K-strategistis, r-strategistis, MI, enrichment index, and channel index. Long-term wild boar grubbing appeared to mitigate seasonal effects on soil nematode communities, resulting in higher MI and increased stability in nematode community abundance. Our findings suggest that changes in soil parameters, such as soil NH4+, soil pH, and soil NO3–, likely mediate the observed impact of wild boars on the soil nematode community. In summary, our study demonstrated that wild boar grubbing altered the structure of soil nematode communities, albeit with seasonal variations, indicating that the effects of wild boar activity on forest soil ecosystems influence biogeochemical cycles through changes in nematode community composition rather than nematode genera richness.

Associating Metrics of Hunting Effort with Hunting Rate: A Case Study with the Wild Boar Sus scrofa

Wild boar Sus scrofa populations have increased dramatically in recent decades throughout Europe. While hunting is widely used in management activities; it rarely has an important role in regulating and reducing wild boar populations. Therefore, increasing the efficiency of hunting is a compelling issue. In this study, we used a three-year dataset (2016–2018) on a wild boar population living in Campania (southern Italy) as a case study to explore how the hunting effort made in collective drive hunts affected the hunting rate, estimated as the number of individuals culled per day. We fitted a Linear Mixed Model, in which we included the number of wild boars culled per drive hunt as the dependent variable, and the number of beaters, shooters and dogs and the month during which hunting occurred as the predictors. A mean of 1.81 wild boars were culled per drive hunt. The number of culled animals per hunt increased with the increasing number of hunting dogs and with the progression of the hunting season (i.e., from October to December), whereas the number of beaters and shooters had no effect. Overall, we observed a low hunting rate. We suggest that adjusting the hunting calendar and reorganising wild boar collective hunts, e.g., through an appropriate management of the number and training of hunting dogs, are essential to increase the hunting rate. Our results can be useful for wildlife managers to enhance hunting contribution in counteracting the negative impact of wild boar.

Quantifying the Immediate Response of Soil to Wild Boar (Sus scrofa L.) Grubbing in Mediterranean Olive Orchards

The goals of the current research were to assess the immediate impact of invasive wild boar (Sus scrofa L.) in olive orchards of southern Italy. Over a one-year study, in grubbed and ungrubbed areas, we measured the seasonal changes on the fast soil biological and chemical responses at depths of 0–15 cm and 15–40 cm, and several leaf and fruit characteristics. The impact factor, IFG, was used to quantify the effects of wild boar on individual soil parameters. Grubbing induced an increase in the soil moisture at both depths. Soil pH, organic matter, and C/N ratio were higher in grubbed soils at 0–15 cm and lower at 15–40 cm compared to ungrubbed soils. These trends were reflected in the higher microbial community biomass and the inhibition of fungal fraction in grubbed topsoil, while an opposite tendency at 15–40 cm was found. Microbial biomass had the highest IFG in topsoil (94%) and metabolic quotient (85%) at a 15–40 cm depth. Microbial stress condition and C loss were found in grubbed soil at both depths. Furthermore, these soils were also shown to be of lower quality than ungrubbed soils, especially at 0–15 cm (SQI = 0.40 vs. 0.50, respectively). A stronger negative impact of wild boar grubbing was observed in the Autumn/Winter and for fruit polyphenol content.

Impacts of wild boars on local livelihoods in rural communities: A case study of mountainous areas in southeast China

Wild boar (Sus scrofa) seriously threatens agricultural production and rural livelihoods worldwide. Human-wild boar conflict has become an important research topic. We investigated the impact of wild boars on local livelihoods and rural community’s responses to the impact, based on a case study in Fu’an City, Fujian Province, Southeast China. We conducted a questionnaire survey of 152 rural households in six villages of Fu’an City. Results demonstrated that the overall impact of wild boars on livelihoods was significant; however, there was impact heterogeneity depending on the mentioned factors. The impact lied on the scale of agricultural output value and the extent of livelihood dependency on susceptible crops. Different impacts resulted in discrepant countermeasures of rural households in dealing with wild boars. The magnitude of economic losses caused by wild boars to a great extent determined the selection of prevention measures. Rural households with more economic losses tend to adopt costly and effective prevention measures, such as fencing and human guarding. Recommendations were put forward to address the human-wild boar conflicts in China.

Understanding the impact of wild boar on the European wild rabbit and red-legged partridge populations using a diet metabarcoding approach

European wild rabbit (Oryctolagus cuniculus) and red-legged partridge (Alectoris rufa) are main small game species of conservation concern in Mediterranean ecosystems. To date, their presence in wild boar’s (Sus scrofa) diet and factors driving their consumption have been little investigated. A genetic metabarcoding approach was used on 80 wild boar faeces collected from four hunting estates devoted to small game hunting during two different seasons. Abundances of wild boar, rabbits and partridges were first estimated. Results showed DNA of seventeen chordate species. The highest frequency of occurrence (FO) corresponded to mammals and birds, with 77.6 and 22.3%, respectively. DNA of game species was detected in 39/71 (FO = 55.0%) samples, highlighting the presence of European wild rabbit in 27 (FO = 38.0%) and red-legged partridge in eight (FO = 11.3%). Dietary composition varied between seasons and estates, being rabbit the main responsible (explaining 35.26% and 39.45% of differences, respectively). Rabbit FO in the diet was positively related to the abundance of wild boar and rabbit density on the estate. It was greater in autumn and in estates where rabbits were hunted. Regarding red-legged partridge, a significant and positive relationship between its population density and its diet FO was observed, without significant differences between seasons or estates. Overall, our results suggest wild boar as an opportunistic species whose diet is largely determined by the relative availability of different food resources. Its ecological role concerning small game species in Mediterranean agroecosystems seems to be more related to consumption of carrion during the hunting season than to direct predation.

The impact of wild boars on the temporal resource utilisation of silver pheasants in South China

Context Increased populations of wild boar (Sus scrofa) in many ecosystems have raised concern regarding the impacts of this species on ecosystems and biodiversity. The relationship between other wildlife and wild boars is not yet fully understood, due to a lack of studies on whether and how other wildlife avoid wild boar interference. Aims This study aimed to investigate the impact of wild boars on the temporal resource utilisation of silver pheasants (Lophura nycthemera). Methods Eighteen infrared camera stations were deployed during the survey period of May 2020 to April 2022. We utilised avoidance–attraction ratios for evaluating the temporal interaction between silver pheasants and wild boars. We also used a kernel density for measuring their daily activity patterns and interspecific overlap. We simultaneously analysed the impact of human activities on silver pheasants as the reference basis for evaluating the degree of interference by wild boars. Key results The total survey effort was 1620 camera days, resulting in a total of 3451 independent detections. The silver pheasants showcased avoidance of both wild boars and human activities (avoidance–attraction ratios were both significantly greater than 1; P < 0.05). The highest degree of temporal overlap was observed between silver pheasants and human activities (Δ = 0.711), followed by wild boars (Δ = 0.615). They both depicted a significant difference in temporal ecological niche differentiation (P < 0.05). Conclusions Our results indicated that wild boars had a significant impact on the temporal resource utilisation of silver pheasants. The presence of wild boars significantly prolonged the recurrent reappearance time of silver pheasants in the same location. To avoid potential interference from wild boars, silver pheasants maximised activity frequencies during low activity periods of wild boars. Implications This study provides useful information for understanding the relationship between wild boars and other wildlife that inhabited the same areas. Future research will need to investigate both individual and combined impacts of wild boars and human activities on other wildlife.

Assessing the Risk of Damages by Wild Boars (Sus Scrofa) in Italian Apennines. Preliminary Report

Wildlife, particularly wild ungulates, has experienced a significant demographic increase throughout Europe, especially in the last 30 years. The objective of this study was to create a preliminary impact map of wild boars (Sus scrofa) in the Molise region of the Italian Southern Apennines, and their correlation with road accidents. A GIS software was used to process a map, and the impact of wild boars was categorized based on land use. An analysis of the environmental characteristics of the neighboring raster was conducted, considering the presence of roads, particularly with respect to accident events. The georeferenced damages were superimposed onto the impact risk map. The geo-referenced damages caused by wild boars indicate that they are primarily concentrated in areas where road accidents have occurred and where there is a high risk of impact. These maps serve as a valuable starting point for managing wild boars in the region by optimizing strategies from technical and economic perspectives. This process must include population control by evaluating the Annual Useful Increase index (IUA), based on processes related to birth-immigration and mortality-emigration of the species.

First complete genomic sequence analysis of porcine circovirus type 4 (PCV4) in wild boars

Porcine circovirus type 4 (PCV4), a unique circovirus with a different classification from other existing circovirus, was discovered in domestic pigs in several provinces of China. In this study, in order to investigate the epidemiology and genetic diversity of PCV4 in wild boars (Sus scrofa), a total number of 138 wild boar samples were collected from five different areas in Jiangxi Province of China, between January 2020 and December 2020. Taqman based real-time PCR were used to test PCV4 as well as PCV1, PCV2, and PCV3. Among 138 samples, 30 samples (21.7%) were positive for PCV1, 31 samples (22.5%) were positive for PCV2, 8 samples (5.8%) were positive for PCV3 and 27 samples (19.6%) were positive for PCV4, respectively. Some of the samples were co-infected with multiple PCVs. In this study, we successfully sequenced the complete genome of two PCV4 strains, which shared 98.5–99.8% of their genomic nucleotide similarity with the other five PCV4 strains discovered in domestic pigs. Phylogenetic analysis showed that the two PCV4 strains derived from wild boars were located in a closed relative branch with other PCV4 strains derived from domestic pigs, but were distinguished from other circovirus. These results of this study not only expand our understanding of the prevalence of PCVs, especially PCV4, in wild boars in Jiangxi province of China, but also showed the molecular epidemiology of PCV4. Nevertheless, the impact of wild boars infected with PCV4 on intensive farmed pigs industry remains to be further explored.

Increasing wild boar density explains the decline of a Montagu’s harrier population on a protected coastal wetland

We studied the rapid decline in the number of breeding pairs (geometric growth rate λ = 0.86; 14 % annual decrease) of a semi–colonial ground–nesting bird of prey, the Montagu’s harrier (Circus pygargus), after twelve years of rapid population growth (λ = 1.15; 15 % rate of annual increase) in a protected coastal wetland in Eastern Spain. The study was conducted from 1992–2017, and the range of values in population size was: 2–37 breeding pairs. We contrasted 20 biologically–sound hypotheses (including local and regional factors) to explain the trend over time in the annual number of pairs. The most parsimonious model included a surrogate of wild boar (Sus scrofa) density in the region during the previous year and the annual number of Montagu’s harrier pairs breeding inland in the study province during the focal year. Syntopic western marsh harriers (C. aeruginosus) were not found to have any effect on the numbers of Montagu’s harriers either in our modelling or when we performed a quantitative and qualitative study both for years t and t–1. Our final ‘best’ models did not include spring rainfall, regional forest fires or local land use changes. The impact of wild boars on breeding success, together with conspecific attraction, could have resulted in the dispersal of coastal wetland birds to larger populations in dense inland shrub lands where levels of wild boar nest predation were more likely lower

Percepción del impacto de cerdos cimarrones (jabalíes) sobre la producción agropecuaria de Argentina

Para conocer la percepción de los productores agropecuarios respecto al impacto del jabalí sobre la actividad productiva y el ambiente, se elaboró una encuesta destinada a tal fin en Argentina, realizándose un análisis descriptivo y estadístico de los resultados. Los productores que respondieron la encuesta se dedicaban en su mayoría a la actividad ganadera (96%) y el 69% realizaba actividad mixta (ganadera y agrícola). El 39% de los productores detectó daños a cultivos provocados por jabalíes, principalmente en cereales (maíz, sorgo, trigo, avena, cebada, centeno) y en oleaginosas (soja y girasol), sin que se hayan demostrado diferencias significativas entre el daño y el tipo de cultivo (p = 0,88). Otros daños fueron deterioros a la infraestructura (30%), animales atacados (20%) y consumo del alimento del ganado (45%). El 37% conoció personas involucradas en accidentes automovilísticos relacionados con jabalíes. De una escala de 1 (dañino) a 10 (beneficioso), el puntaje promedio del jabalí fue de 3,16 (desvío estándar = 2,27). En algunas zonas este animal fue considerado beneficioso debido a su uso como especie cinegética (cacería). No obstante, el jabalí resulta ser un problema relevante para gran parte de los productores agropecuarios pues se lo asocia a pérdidas económicas importantes. Considerando que los productores son destinatarios directos del impacto benéfico que tendría la disminución de la cantidad de jabalíes, su concientización respecto al tema resultaría alentadora, favoreciéndose el desarrollo de controles poblacionales de la especie, involucrándose a las autoridades ambientales y las vinculadas a la industria agropecuaria.

Does wild boar rooting affect spatial distribution of active burrows of meadow-dwelling voles?

Soil overturn by wild boar Sus scrofa is known to affect biodiversity, from plant communities to invertebrates, reptiles and small mammals. Rooting activity has been shown to be particularly intensive in open areas and particularly on fallows and meadows located on hill or mountain tops. In these habitat types, the impact of wild boar on small mammal assemblies has never been assessed. In this work, we evaluated whether rooting activity affected the spatial distribution of the Savi’s pine vole Microtus savii in a hilly area of Central Italy, throughout four seasons. The spatial distribution of this vole has been determined through the open-hole index, i.e. by assessing the vole propensity to reopen tunnel entrances which we previously closed with soil. Rooting intensity was the highest in cold months, i.e. when drive hunting may increase wild boar occurrence within protected areas and outside wooded areas. According to our GLMM, reopening of vole burrow entrances increased with increasing distances from rooted areas and with increasing geophytic diversity. Meadow-dwelling voles living on shallow underground burrow systems seem to avoid soil overturn by wild boar and that they prefer creating their tunnels where plant diversity building up the staple of their diet is the highest. Our results furtherly emphasized the importance of wild boar monitoring also in open areas and hill grasslands, particularly when rooting intensity is the highest, i.e. in cold months.

Estimating wild boar density and rooting activity in a Mediterranean protected area

The mitigation of ecological/economic impacts of wild boar Sus scrofa is one of the most challenging issues in wildlife management worldwide. Monitoring population density and impact of wild boar is crucial to plan appropriate management actions to reduce its density, environmental impact and epidemiological risk, as well as to evaluate control effectiveness. In 2018–2019, we used plot-based faeces counts, coupled with specific estimates of daily defecation rates, to estimate wild boar density and rooting activity in natural/semi-natural habitats, in a Mediterranean protected area. Daily defecation rate was 6.7 faeces/individual, much lower than that of ruminants. We obtained estimates of 70.0–70.5 faeces/km2, corresponding to wild boar densities of c. 10.5 individuals/km2 (relative standard error: 18%) in both years. Low daily defecation rates and skewed distribution frequencies of wild boar faeces should be considered to plan surveys with an adequate sampling design and intensity. Faeces abundance and rooting activity peaked in ecotones, i.e. open areas at the interface of wood patches, whereas they did not differ between other habitat types, suggesting a fine-scale concordance between the two indicators. Long-term monitoring is needed to assess relationships between indicators of impact and abundance at a broad scale. Our work shows how to undertake simultaneously wild boar density estimates and impact assessment in natural environments, which is particularly important for protected areas and/or habitats of conservation concern across the globally distributed Mediterranean biome.

Impact of wild boar rooting on small forest‐dwelling rodents

AbstractAssessing impacts of wild boar on ecosystems is a research priority worldwide, with applied implications for environmental management. We evaluated whether rooting intensity by wild boar affected a rodent community in Central Italy. Rooting intensity was measured within trap transects and all around them, following standard procedures. We live‐trapped rodents in coppiced forests with a gradient of rooting intensity (including a fenced, boar‐proof, area) and evaluated relationships between abundance and rooting for two arboreal and five ground‐dwelling species. Among those, the most abundant ones were the bank vole Myodes glareolus and the yellow‐necked wood mouse Apodemus flavicollis. Rooting within and outside transects correlated to each other, as well as with the local passage rate of the wild boar, assessed through camera‐trapping. We found a negative relationship between rooting intensity and abundance of bank voles, that is, the main food resources of some predators of conservation concern. Rooting activity may trigger effects on ground‐dwelling rodents at the population level.

Influence of seasonality, environmental and anthropic factors on crop damage by wild boar Sus scrofa

In recent decades, wild boar Sus scrofa populations have increased both in number and distribution in Italy, thus enhancing problems of cohabitation with humans. Crop damage represents one of the main sources of conflict; understanding the spatiotemporal variation of damage events and which factors increase the risk of damage is crucial to the development of effective management strategies. The aims of this study were to determine the impact of wild boar on croplands in the Special Protection Area “Risaie della Lomellina” (western Po Plain, northern Italy) and to formulate a risk prediction model through a binary logistic regression analysis. Damage events almost exclusively involved maize, and were concentrated in spring and summer. Sporadic cases of damage concerned rice, soybean and sorghum fields. The risk of damage was higher in fields close to forests, far from main roads, urban areas and continuous hedgerows, and in areas with low human population densities.

Impact of wild boars on the feeding behavior of smaller frugivorous mammals

We examined the interspecific relationships among wild boars, raccoon dogs, and badgers with regard to the consumption of fallen fruits to assess how the presence of the largest mammal, the boar, affects the frugivory behavior of the two smaller species. In our 2-year survey, automatic cameras were set under the crown of wild cherry trees to observe frugivory; all mammals had access to the trees in the first year, but only wild boars were blocked access with a fence in the second year. The survey was conducted in a temperate broad-leaved forest in central Japan. All three species frequently visited those trees with abundant fruit production, and the presence of wild boars affected the feeding behavior of smaller badgers and raccoon dogs. When wild boars were present, the raccoon dogs partly shifted the time of day when they fed and tended to shift to places that the wild boars visited infrequently. In contrast, the badgers partly shifted the time of day when they fed and reduced their feeding time per visit. When wild boars were excluded from the area, raccoon dogs and badgers, which are generally nocturnal, consumed fruit under the crown not only at night but also during the day. The reason for this may be that the smaller species may not have yet responded to the sudden exclusion of the boar as a competitor. Our findings indicate that these three frugivorous mammals exhibit resource partitioning of fallen fruits on the forest floor.

Catastrophic impact of wild boars: insufficient hunting pressure pushes snakes to the brink

AbstractClimatic changes, habitat loss and invasive species are important threats for many animal populations. Here, we report rapid declines and extinctions of adder populations monitored during 12 years in Belgium where none of the above causes was involved. This study provides the first large‐scale data showing that wild boars represent a major risk for snakes, pushing populations to extinction. Drastic population declines were observed in the sites impacted by wild boars (N = 14), while in other sites spared by wild boars populations remained stable (N = 9). Wild boars are highly fertile and their main predators have been extirpated from Western Europe; yet, recreational hunting kept populations in check during decades. Hunting pressure is currently insufficient to control the rapid expansion of wild boars, demographic outbreaks are increasingly frequent. Wild boars are omnivorous; they can destroy snakes directly and indirectly through the depletion of snake's preys and via the destruction of key microhabitats. Snakes exhibit limited dispersal capacities; they cannot escape local perturbations and thus are highly vulnerable. Because wild boars have a very eclectic diet, are prolific breeders and are able to devastate a range of habitats their negative impact under relaxed hunting pressure applies to a huge variety of organisms, including reptiles. Policies to limit wild boar populations are urgently needed. Recommendations to target reproductive females and piglets should be generalized and applied.

Potential impact of Wild boar (Sus scrofa) on Pheasant (Phasianus colchicus) nesting success

In recent decades wild boar have greatly increased in Europe due a combination of environmental and human factors. Because of a high reproduction rate, wild boar cause conflicts with human activities and in particularly agriculture. However, there are concerns also about environmental impact and in particular on ground nesting birds. Our study aim to evaluate the potential impact of wild boar on pheasants nests. Predation rates were compared between two areas with different wild boar abundance and between nests placed in fenced plots with no wild boar access (but accessible to other predators) and open plots in which the wild boar gains access. Predation rate by wild boar in the area with higher wild boar abundance was 61.5% whereas in the area with lower abundance was 16.0%. In plots with free access, wild boar predation was 34.2% whereas in exclusion plots we did not registered predation by wild boar. Moreover, wild boar resulted the main nest predator (total loss 22.8%). Our findings suggest that wild boar could have e strong impact on pheasant reproductive success.

Wild Boar Impact to the Natural Regeneration of Oak and Acorn Importance in its Diet

In this study, the impact of wild boar on the natural regeneration of oak and importance of acorns in the wild boar diet were surveyed. The data were collected near Moravian Krumlov (Czech Republic) in three types of oak stands differing in the canopy density: fully-stocked stand (1), open-canopy stand (2) and the forest stand in a conversion to the coppice forest (3). Within each stand 150 m long lines were set out. Seed traps to collect acorn harvest and control plots were installed on these lines. The plots were inspected at weekly intervals. After the end of acorn fall the average amount of fallen acorns was evaluated. The quantity of metabolizable energy in acorns was assessed and daily survival dose of energy for average weight of wild boar was counted. In spring 2014 the number of seedlings was counted at the same plots. Production of acorns per hectare and basic energy needs for one individual wild boar per day were evaluated for each chosen stand type. The found seedling density amounted to 29,600, 32,000 and 14,000 ind./ha in the first, second and third stand under study, respectively. Wild boar is a major consumer of acorns. In the studied area the production of acorns sufficiently supplied the local wild boar population during winter. Necessary amount of acorns remained for the natural regeneration.

Complexes of Formica s. str. nests in the Darwin Nature Reserve and causes of their degradation

Nest complexes of Formica ants were studied in the Darwin Nature Reserve, in Rybinsk Reservoir basin (Vologda and Yaroslavl Provinces). A strong negative influence of wild boars was demonstrated based on the data of 1997–2012. Boars damage ant nests, which may lead to their complete destruction. The adverse influence of boars is intensified in the years with high water levels in the reservoir, when the boars cannot feed in the temporary inundation zone and thus increase their impact on the forest and ant nests. Due to the long succession of highwater years since 2004 and the resulting strong impact of wild boars, the number and size of ant nests drastically decreased, and the abundance and biomass of Formica ants in forest ecosystems were reduced.