From 2000 to 2021, the number of wild boar damage incidents in China showed a significant annual increase (Figure 2), with a fitted curve showing an exponential function (y= 5.8748e^0.124x, R²=0.878). The wild boar damage incidents experienced roughly three stages of development, with the number of damage incidents not exceeding 10 per year before 2003, between 20 and 40 per year from 2004 to 2016, and exceeding 40 per year after 2017, with the growth rate increasing further after 2018. In 2021, the number of damage incidents even exceeded 100, indicating a trend toward social risk.

Figure 3 shows the number of districts (counties) in China where wild boar damage incidents occurred increased from 67 in the early period to 399 in the recent period. The number of cities also increased from 41 in the early period to 147 in the recent period, and the number of provinces increased from 18 to 25. From 2000 to 2005, there were 67 districts (counties) where wild boar damage incidents occurred in China, mainly distributed in the hilly and mountainous counties of Chongqing municipality, as well as Hubei and Jilin provinces. After that, the damage incidents expanded from Chongqing and central-western Hubei to the surrounding areas. From 2005 to 2010, 42 new districts (counties) where wild boar damage incidents occurred were added, expanding from Chongqing, Hubei, and other areas to the hilly and mountainous counties of Anhui, Zhejiang, and other provinces. From 2010 to 2015, there were 67 new districts (counties) where wild boar damage incidents occurred, expanding further into eastern, southeastern, and northwestern mountainous counties on the basis of the original spatial area. From 2015 to 2021, 223 new districts (counties) where wild boar damage incidents occurred were added, mainly concentrated in the hilly and mountainous counties of Sichuan, Guizhou, the southeastern part of Gansu, and the central-southern part of Shaanxi, gradually forming the current spatial pattern of wild boar damage incidents. It is worth noting that among the 399 districts (counties) where wild boar damage incidents occurred in recent years, 291 of them were in mountainous counties, accounting for 72.93% of the total. Generally speaking, incidents involving wild boars are more common in mountainous counties where hilly and mountainous terrain is the predominant natural geographical feature.

Currently, the human-wild boar conflicts have become an international issue, and the wide-open spaces and strong survival ability of wild boars are the main reasons for frequent incidents of wild boar damage (Snow et al., 2017; Castillo-Contreras et al., 2021). In China, human-wild boar conflicts mainly occur in hilly and mountainous areas such as the Sichuan Basin, the Loess Plateau, the middle and lower reaches of the Yangtze River, and the Changbai Mountains. The driving factors behind these conflicts exhibit distinct characteristics, and the root cause is the result of the combined effects of various factors such as ecological engineering, ecological environment restoration, hunting bans, unclear boundaries between agricultural land and ecological land, the strong survival ability of wild boars, and the lack of natural enemies.

First, the implementation of ecological engineering and improvements in the ecological environment have played significant roles in this context. In order to improve the ecological environment, China started a pilot project for returning farmland to forests and grasslands in 1999. According to the White Paper Twenty Years of Returning Farmland to Forests and Grasslands in China (1999-2019), released in 2020, approximately 34 million ha of farmland have been returned to forests and grasslands over the past 20 years, resulting in significant improvement of the ecological environment (Yang et al., 2020). Since 1994, China has been confiscating hunting guns nationwide and has banned hunting for over 20 years. In 2000, the List of Terrestrial Wildlife Protected by the State that are Beneficial or of Important Economic, Scientific and Research Value (Order No.7 of the State Forestry Administration) included wild boars in the scope of “three-have” protected animals and the population of wild boars began to recover. Simultaneously, farmers were prohibited from privately hunting wild boars except for driving them away, there are no other effective methods, which led to their population increasing continuously.

The amelioration of the ecological environment in these mountainous regions has provided an advantageous living environment for wild boars, resulting in their continued population growth. The process of urbanization, coupled with the escalating costs of agricultural labor, has prompted young laborers in rural areas to seek employment outside their villages. Consequently, the urban population experiences an annual growth of approximately 21 million individuals, while the rural population steadily declines. From 1995 to 2020, the agricultural labor force in China witnessed an average annual decrease of approximately 11 million people, with more pronounced reductions observed in mountainous regions (Li et al., 2015). At present, rural population mainly consists of women, children and the elderly, and their reliance on land has significantly diminished. This shift has resulted in changes in land use practices and intensity, gradually improving the ecological environment in rural areas (Li et al., 2017b). For instance, since the 1990s, rural areas have progressively transitioned to using gas as a fuel source, thereby reducing reliance on firewood (Lu et al., 2022). In addition, affected by national policies such as relocation and poverty alleviation, villagers living in mountainous areas, especially deep mountains, have gradually relocated, diminishing human disturbances in mountain forests. Consequently, vegetation in mountainous areas has recovered, leading to a significant improvement in the ecological environment (Li et al., 2017b; 2018; Lu et al., 2022).

Another significant driver of conflicts lies in the ambiguous and overlapping boundary between farmland and ecological land. As agricultural activities and urban development intensify, ecological land continuously succumbs to encroachment by agricultural and urban expansions. The growing demand for land resources due to population growth has led to the expansion of farmland into forests, encroaching on the original habitat of wild boars (Huang et al., 2021b). As the habitat range of wild boars decreases, they are forced to enter new areas for activities and foraging, and consequently, crops in the edge areas of forests become the target of wild boar destruction (Wang et al., 2018). Presently, hotspots of wild boar damage incidents are predominantly concentrated in regions such as the Sichuan Basin, Loess Plateau, middle and lower reaches of the Yangtze River, Changbai Mountains and other hilly areas, mostly in the areas where agriculture and forestry are intermixed, with farmland and forest spatially overlapping. Compared with wild plants, wild boars prefer food in farmland, such as corn, sweet potatoes, and peanuts, which are all high-quality food for wild boars. During crop maturation periods, wild boars will enter the farmland to feed, causing large-scale damage to crops and even complete crop failure (Hua et al., 2016). In addition, in recent years, China has carried out large-scale ecological protection red line delineation, which was completed at the end of 2020. The delineation of ecological protection red lines has a large area, a wide range, and strict control, resulting in significant improvement in the ecological system’s service value. However, it has also exacerbated the conflict between humans and wild boars to a certain extent (Wang et al., 2018).

Finally, the strong survival abilities and lack of natural predators among wild boars contribute to the conflicts. Wild boars have high reproductive capacity, with an average litter size of 6 to 8 piglets and reaching sexual maturity at 14 to 18 months of age (Jiang et al., 2018). The Zhejiang Province Terrestrial Wildlife Resources Survey Report shows that in 2000, there were about 29,000 wild boars in the entire province, which increased to over 100,000 in 2006, and reached 150,000 by 2010, a fivefold increase in just 10 years. It is estimated that there are currently over one million wild boars in China, with some areas experiencing an “overpopulation” situation. Wild boars are adaptable and omnivorous animals with large appetites (Richard et al., 2004). They can quickly adapt to different environments and are active in hilly areas, where they dig the soil and feed on crops. Due to the low population of large carnivorous mammals that serve as natural predators of wild boars, such as tigers, leopards, bears, and wolves, and their slow population recovery, wild boars lack natural predators (Nyhus et al., 2004) and their populations have been growing rapidly.

The conflict between protecting wildlife and ensuring the safety of people’s lives and property is a serious challenge facing China in achieving harmonious coexistence between humans and nature. Therefore, how to handle the relationship between ecological conservation and social and economic development needs to be examined from the perspective of ecosystem services (Li et al., 2013; Jiang et al., 2021). Generally speaking, ecosystem services can be divided into “long-term” services and “short-term” services, with “long-term” services being the ultimate goal of ecological civilization construction to achieve harmonious coexistence between humans and nature, but it requires multiple “short-term” services processes. However, as the ecological environment gradually recovers, the adverse impacts of the ecosystem on human production and life gradually become apparent, that is, the phenomenon of ecosystem disservices (Shackleton et al., 2016). In recent years, with the increasingly prominent negative impacts of ecosystem improvements on humans, the issue of ecosystem disservices has gradually received attention from scholars (Shackleton et al., 2016; Yang et al., 2019), but there is still no unified standard for its definition. Generally, ecosystem disservices are perceived or actual negative impacts on human well-being caused by the functions, processes, and attributes produced by the ecosystem (Shackleton et al., 2016), mainly manifested in direct impacts on human well-being from ecosystem processes or attributes, reduced ecosystem service functions due to ecosystem damage, and negative impacts on human well-being derived from ecosystem processes, such as wildlife damaging farmland, snake bites, and pollen allergies (Shackleton et al., 2016; Yang et al., 2019).

Ecosystem disservices require some natural elements to form an ecosystem, and these elements can have adverse effects on humans. Based on the characteristics and classification standards of ecosystem disservices, it can be determined that an increase in the population of wild animals, represented by wild boars, is a reflection of the improvement of the ecosystem. However, when the population of wild boars increases to the point where they destroy crops, harm poultry, or attack humans, causing negative impacts on local residents’ production and livelihoods, it becomes a typical manifestation of ecosystem disservices (Hua et al., 2016; Yang et al., 2020). It is worth noting that the current conflict between humans and wild boars in China is concentrated in the hilly and mountainous areas of the agricultural-forestry mixed zone, which overlaps spatially with the areas of serious fallow land, poverty alleviation, and ecological vulnerability, that is, the “four zones overlap,” seriously affecting fallow land management, improving farmers’ livelihoods, and promoting regional ecological security, and has become the most typical and representative manifestation of ecosystem disservices.

As the nation intensifies its efforts to protect the ecology and ecological environment in various regions continue to improve, the negative impact of wild animals, represented by wild boars, on the production and livelihoods of rural residents has spread from sporadic to extensive areas, reaching the hilly and mountainous counties in China. This has led to about 6.7 million ha of farmland facing abandonment, 40 million t of grain production capacity being damaged, and the livelihoods of 30 million farmers being affected. At present, local governments should actively formulate strategies for regulating the population of wild boars and improve the corresponding compensation mechanism for damage by wild boars, in order to alleviate the harm caused by conflicts between humans and wild boars. The following measures can be implemented:

Firstly, the National Forestry and Grassland Administration has revised the draft of the List of important terrestrial wild animals with ecological, scientific, and social values, removing wild boars from the list. This revision provides legal support for the scientific and phased protection of wild boars. To scientifically and moderately hunt wild boars, detailed assessments are required concerning hunting time, quantity, range, and frequency of wild boars in different regions, and supervision should be strengthened during the implementation process. Moreover, China currently has approximately 12,000 nature reserves, accounting for about 18% of the land area. Inside the nature reserves, the regulation of the population of wild animals and plants should be based on the protection of wild animals and plants, ensuring the normal functioning of the ecosystem, and the evolutionary potential of biological species. Given the vegetation destruction caused by wild boars in nature reserves and their competition for food with other herbivores, the population density of wild boars needs to be adjusted under strict scientific demonstration. Introducing natural enemies of wild boars and restoring the food chain of the ecosystem, as well as conducting scientific experiments such as sterilization, can also be considered. Outside the nature reserves, encompassing 82% of the national land, the regulation of wild animals and plants population should focus on safeguarding the production and livelihoods of humans and ensuring their safety, as well as controlling the rapid growth of the population of wild boars.

Furthermore, providing compensation for damages caused by wild boars is an effective economic measure to reduce the occurrence of such damage. Economic compensation can increase the tolerance of local residents towards wildlife, reduce retaliatory hunting, and promote wildlife conservation while balancing the costs and benefits of protecting wildlife (Zhou et al., 2008). Article 19 of the Wildlife Protection Law stipulates that “compensation shall be given by the local people’s government for personal injury or damage to crops or other property caused by wildlife protected by law. The funds needed for prevention and control of the harm caused by the key protected wildlife and the compensation shall be subsidized by the central finance in accordance with the relevant regulations of the state.” However, currently, only provinces such as Beijing, Shaanxi, Anhui, and Gansu have implemented compensation measures for personal and property losses caused by key terrestrial wildlife protection, and there are problems such as low compensation standards and difficulties in assessing the degree of damage. Therefore, the government should formulate detailed loss assessment standards and compensation systems, choose some pilot areas, and promote them comprehensively as soon as possible.

Drawing on the “pivot” concept model of the human-environment relationship evolution mechanism (Dong et al., 2021), this study explores the synergistic evolutionary relationship between natural ecological systems and social-economic systems (Figure 9). Under certain organizational structures and technological levels, the evolution of natural ecological systems and social-economic systems is influenced by multiple factors, such as human activities and climate change. When humans carry out activities such as returning farmland to forests and grasslands or banning hunting in a specific area, or when the climate environment improves, the ecological environment in that area improves, providing a good living environment for certain species of wildlife (such as wild boars). The population of the wildlife species grows rapidly, leading to the abandonment of farmland in the area, a decline in the livelihoods of farmers, and even forcing them to relocate. At the same time, the growth of the wildlife population is further fueled, exhibiting a typical ecosystem disservices phenomenon (Wang et al., 2018). Conversely, when humans engage in activities such as excessive grazing or excessive land cultivation in a specific area, the ecological environment in the region deteriorates, leading to a loss of biodiversity and ecological imbalance. For example, an excess of rodents (due to a lack of natural predators) can lead to crop failures and a decline in the sustainability of farmers’ livelihoods, exhibiting a typical decline in the value of ecosystem services (Dong et al., 2021). Both of the above states are imbalanced states of natural ecological systems and social-economic systems, and the two systems are difficult to synergistically evolve. Only when the natural ecological system and social-economic system are in a certain balance range, can the natural ecological system and social-economic system synergistically evolve. At this time, the ecosystem can fully play its potential ecosystem service value, thereby promoting harmonious coexistence between humans and nature.