An Empirical Study on the Effects of the “Sky Window” Policy on Household Income in Rural Communities: Evidence from Wuyi Mountain National Park

Abstract

The increasing contradiction between ecological conservation and community development is a common challenge faced in most protected areas worldwide. Since 2019, China has used a “sky window” policy to alleviate the dilemma of environmental protection and sustainable production activities in national parks. This policy’s impact on household income in national park communities has received little attention. In this study, we aimed to evaluate the impact of the sky window policy on household income in Wuyi Mountain National Park communities in China and explore its mechanism of action in order to provide policy recommendations for achieving the protection goal of the national park and enabling win–win development of the community. Based on a total of 951 samples, which were collected through face-to-face interviews with 518 households in two periods, we used the difference-in-differences (DID) model to obtain consistent results and conducted robustness tests on the model by employing propensity score matching (PSM). The results showed that the “sky window” policy had a significant negative impact on the income of households in national park communities, which was mainly caused by the relaxation of restrictive regulations on farmers’ planting and breeding activities within national parks. The findings indicate that government departments in China need to further improve the laws and regulations regarding national park construction, establish a dynamic evaluation mechanism to regularly review the effects of the “sky window” policy, and make timely adjustments based on changes in the ecological environment of national parks and the development needs of local communities. At the same time, to ensure a stable source of income for residents, it is also necessary to establish a platform for realizing the value of ecological products, strengthen support for livelihood transformation, and establish long-term benefit linkage mechanisms. This study contributes to the research on the effective management of national parks, community welfare improvement, and sustainable development in developing countries.

1. Introduction

The Earth is experiencing a biodiversity crisis, which has sparked urgent global calls for the protection of the world’s oceans and terrestrial ecosystems [1]. Over the past century, countries have carried out practical explorations to varying degrees based on their resource endowments and fundamental national conditions. Through this process, the concept of nature conservation and management models has continuously evolved and developed, gradually accumulating into a rich system of experiences in national park construction [2,3,4]. In many countries, the establishment of national parks is regarded as a crucial strategy for mitigating the adverse impacts of external pressures on biodiversity [5,6,7]. Nevertheless, the various stringent regulatory measures implemented in national parks may force residents in surrounding communities to engage in illegal hunting, logging, and over-exploitation of resources to make a living, exacerbating the contrast between ecological protection and community development [8,9]. As a result, the conflict between ecological protection goals and the livelihood development of residents continues to escalate, becoming one of the main obstacles restricting the improvement of national park management efficiency [10,11,12,13].

The impact of the management and construction of national parks on the livelihoods of local residents has received widespread attention in recent years. From a global perspective, due to differences in national conditions and park characteristics in various countries, a diverse range of impact situations has emerged. Existing studies have shown that, due to factors such as regional economic development levels and management systems, the impact of national parks on residents’ household income and community development varies significantly. On the one hand, in terms of developed countries, numerous studies have found that national parks promote income growth by transforming residents’ household income structures [3,5,14,15]. In many countries, park construction has driven the rise in ecotourism and supporting service industries, optimized community participation management models, and created new income sources for community residents [16,17]. Taking Yellowstone National Park as an example, the surge in tourist numbers has directly improved the prosperity of industries, such as accommodation, catering, and guide services. Some residents have obtained stable rental income by operating homestays [18,19,20]. Japan’s current national park system focuses on the provision of cultural ecosystem services, such as recreational opportunities. The protected landscape concept emphasizes the relationship between nature, livelihoods, and communities, which contributes to the development of the community economy [21]. Australia’s Uluru-Kata Tjuta National Park and Germany’s Bayerischer Wald National Park benefited economically by collaborating with local communities to develop characteristic tourism projects. This model, which integrates culture with tourism, not only enriches tourists’ travel experience but also provides substantial economic returns to community residents [22,23,24]. Additionally, a large number of studies have indicated that the construction of national parks has promoted the improvement of infrastructure and public services. For instance, in some national parks in Canada, such as Banff, the government has increased investment in infrastructure, which has not only enhanced the convenience of community life but also provided strong support for the economic development of the community [25,26].

On the other hand, in some developing countries, the establishment and management measures of national parks have had varying impacts on their community development. For example, Serengeti National Park in Tanzania and some national parks in Kenya have adopted co-management arrangements, as well as promoted the construction and renovation of community schools and medical facilities through collaboration with local governments, directly improving residents’ educational attainment and health security levels [3,27,28]. Additionally, a case study of Manu Biosphere Reserve in Peru indicates that supporting indigenous communities’ contributions, empowering their environmental stewardship and avoiding a shift towards intensive agriculture often applied by immigrant groups, are critical to fulfilling the conservation role of national parks and improving social and economic development [29]. Brazil’s Iguaçu National Park is currently facing substantial impacts from illegal hunting, fishing and palm-heart extraction, and although local illegal actors profit from it, this approach is not sustainable [30]. However, many studies have also shown that the protection measures and institutional deficiencies of national parks have had a variety of negative impacts on local communities due to the demand for economic development in developing countries. For example, the transportation problems related to inadequate infrastructure construction have had a negative impact on the tourism industry of Kruger National Park in South Africa, hindering the development of local communities [31]. Further, traditional livelihood patterns have been impacted. In Kenya’s Maasai Mara National Reserve, in order to protect the ecological environment within the park, the grazing areas of the Maasai people have been unreasonably reduced, restricting their traditional nomadic lifestyle [32]. As a result, Maasai residents, whose main source of income is animal husbandry, are facing the challenge of reduced income. In addition, traditional agricultural production has also been restricted in some national parks. For example, to protect water sources or biological habitats, some arable land has been included in protected areas, and the use of modern agricultural production materials, such as chemical fertilizers and pesticides, has been prohibited, resulting in a decline in crop yields, thus directly affecting income [8,33]. For families whose arable land and forest land have been adjusted due to policies, the imperfect ecological compensation mechanism—such as low compensation standards and delayed payment of compensation—also has a negative impact on household income [34,35]. Furthermore, in countries such as Nepal, during the construction of national parks, due to unbalanced interest distribution, different community residents may encounter uneven distribution of benefits when participating in tourism development, ecological protection, and other projects, thereby intensifying internal conflicts [17,34,36].

As a typical developing country, the original intention of establishing national parks is to protect biodiversity. The distribution of national parks in China is uneven, but most of them are located in economically underdeveloped areas. Due to the heavy reliance of local residents on natural resources for their production activities, there is a contradiction between environmental protection and community development. This realistic background prompted China to make efforts to improve the construction and management of national parks. Since the establishment of the first batch of five national parks in 2021, China has promoted high-quality development through high-level protection and actively explored new models for the construction of the national park system. In addition to ecological compensation mechanisms and community co-management models, China proposed a new management policy known as the “sky window” policy in 2019, which is an important means of resolving the conflict between ecological protection and community development in the integration and optimization of natural protected areas in China. Its essence is to adjust the boundaries of protected areas and remove land parcels that conflict with protection goals (such as built-up areas, villages, and farmland) from the boundary range, while keeping the geographical space within the protected area [37,38]. However, since the launch of national spatial planning and the integration and optimization of national nature reserves, with national parks serving as the main body, the topic of the “sky window” policy has highly attracted the focus of various sectors of society and is even considered controversial. Many studies have analyzed the impact of the “sky window” policy on mitigating ecological protection and sustainable community development from a theoretical perspective. The Chinese Ministry of Natural Resources and other management departments have emphasized that it is extremely necessary to include the “sky window” in the unified monitoring and scientific control scope of ecological protection red lines [39]. Applying the “sky window” policy within national parks to preserve farmland, residential communities, mineral resource areas, or reserve development zones will enable the implementation of ecological protection and control policies, meet the relevant interests of original residents and rights holders, and reserve greater space for future development [40]. On the contrary, some scholars have argued that the “sky window” policy has turned national parks into a sieve, which is likely to trigger new livelihood risks, thereby eliminating their protective significance [41,42].

Wuyi Mountain National Park (WMNP) is one of the first batches of officially established national parks in China. It is not only a global human and biosphere reserve but also a national park under the World Natural and Cultural Heritage list [43], and it has been widely studied. It is generally believed that at the beginning of the construction of WMNP, the conflict between humans and nature remained quite severe [42]. Ecotourism has introduced many benefits to local communities. Measures such as ecological forest protection compensation and easement management are also pioneering initiatives of WMNP [44]. However, research has shown that local communities are still dissatisfied with some management practices of the national park, especially when faced with resource usage restrictions [38]. Regarding the “sky window” policy, community feedback has been mixed. Therefore, research methods for coordinating the relationship between ecological protection and sustainable community development through effective policies and measures are an important issue.

There are still some research gaps worth amending when examining the most relevant studies on the impact of the “sky window” policy on the welfare of residents in national park communities. Firstly, recent research has mainly examined the potential impact of the policy on local communities from a theoretical perspective, lacking systematic quantitative analyses. The analysis results based on empirical data can reveal the impact and effectiveness of the “sky window” policy, which facilitates the adjustment and optimization of the policy. Secondly, although many studies have analyzed the advantages and disadvantages of implementing the “sky window” policy, few have focused on the impact of this policy on the income level of community residents. Thirdly, the potential mechanism of the impact of the policy on household income in national park communities remains to be explored, which is of great significance for implementing more targeted policies.

This study contributes to the research on the effective management of national parks, community welfare improvement, and sustainable development in developing countries. The contributions of this study are multiple in nature. Firstly, the impact of the “sky window” policy on the household income of communities in Wuyi Mountain National Park was quantitatively assessed for the first time; the findings have strong practical value and innovation. Secondly, the relevant mechanisms of the impact of the “sky window” policy on residents’ income were discussed, providing more targeted policy recommendations for the sustainable development of the community. Finally, our findings enrich the relevant research on the effectiveness of administrative measures with respect to adjustments of the boundaries of national parks, and we provide experience and practices for other developing countries to manage their national parks.

The rest of this article is divided into the following sections. Section 2 provides a literature review and the conceptual framework. Section 3 introduces the methodology, including sampling and data collection, variables, and model specification. Section 4 presents the results of descriptive analyses and empirical results from DID and PSM models. Section 5 presents the discussion and policy implications. Section 6 provides our conclusions.

2. Literature Review and Conceptual Framework

2.1. Literature Review

In June 2019, the General Office of the Communist Party of China Central Committee and the General Office of the State Council issued the “Guiding Opinions on Establishing a Nature Reserve System with National Parks as the Main Body”, which comprehensively launched the integration and optimization of nature reserves for the first time [45,46]. Since then, the implementation of the “sky window” policy in national parks has become more standardized.

Current academic research on the impact of the “sky window” policy is mostly focused on the theoretical level, especially in China, where government departments are particularly concerned about this policy. The Ministry of Natural Resources and other departments posit that it is extremely necessary to include the “sky window” in the unified monitoring and scientific control scope of ecological protection red lines. Retaining farmland, residential communities, mineral resource areas, or reserving reserve development areas through a sky window within natural protected areas can not only better implement ecological protection and control policies but also meet the relevant interests of original residents and rights holders and reserve greater development space for future development [41]. However, many scholars have raised different opinions, finding that the “sky window” policy has resulted in the fragmentation of protected areas and has lost the original ecological protection intention [47]. In addition, some studies have found that residents of window communities hold negative attitudes towards the delineation and management mechanisms of the sky window, insisting that they have adverse effects on family production and life [44,48]. In response to this situation, the Chinese government has introduced some countermeasures. First, it proposes that the land parcels that create the “sky window” via the transfer of natural protected areas for permanent basic farmland should be backfilled and retained within the natural protected areas. Permanent basic farmlands should be gradually transferred out by local authorities, and they should still be counted, utilized, and managed according to cultivated land practices. The specific vector data of the land parcels will be issued uniformly [49]. Second, it is necessary to reasonably backfill the “sky window” plots that do not generate conflicts and contradictions and to leave the plots that truly offer protective value within the natural protected areas. The plots that need to be backfilled should be evaluated, and the reasons for backfilling should be explained. In addition, if a project is no longer being implemented, the site’s selection changes, the land use scope is significantly reduced, or the mining rights are lost due to the transfer of project land or mining rights. The unused part should be backfilled to a natural protected area in principle [50]. However, although the disposal method is not a one-size-fits-all approach to backfilling, it still poses a severe problem with respect to the governing ability of local governments at all levels. Problems such as handling the relationship between protection and development and determining which areas should have a “sky window” and which areas must be backfilled still require urgent resolution.

Although research on the “sky window” policy by the academic community remains limited, research related to protected land boundaries is well established. Although the term “sky window” is not directly used abroad, many countries have taken similar measures in the management of national parks or protected areas, such as boundary adjustments; protected area downgrading, downsizing, and degazettement (PADDD); zoning; or community-based conservation, to balance ecological conservation with human needs [51,52,53,54]. Research in the Maasai Mara National Park shows that boundary adjustments result in a decrease in the carrying capacity of the land on the edges of the protected area and an increase in the risk of vegetation degradation. Moreover, herdsmen have passively shifted from traditional nomadism to tourism services, resulting in increased income fluctuations. In addition, border adjustments have resulted in difficulties in confirming indigenous land rights and restricted logging and mining activities [55]. PADDD refers to adjusting the boundaries of protected areas, reducing protection levels, or completely revoking protection status through legal means, similar to the removal of conflict areas in the “sky window” policy [52]. For example, the road proposal includes downgrading the protected status of a portion of the park, which reflects a worldwide pattern of downsizing, downgrading, and degazetting protected areas that is particularly evident in Brazil [30]. Zoning is the process of protecting internal partitions within a protected area, such as core zones, buffer zones, and traditional use zones, allowing communities to operate in specific areas. Through zoning management, the biodiversity within the core protected area can be significantly restored, and communities are able to obtain limited resource use rights to develop ecotourism, reducing land disputes between communities. Brazil’s Iguaçu National Park delimited the buffer zone to include illegal activities registered in forest areas [30]. However, there are also some problems, such as insufficient regulatory capacity in remote areas, inadequate implementation of zoning rules, income decline for residents in core areas due to activity restrictions, differences in zoning standards between local governments and communities, and low implementation efficiency [53,56]. A community-based conservation policy grants local communities management rights and allows for sustainable resource use within the conservation area, which is considered an effective measure for achieving both resource conservation and community development [54,57]. Germany’s Bayerischer Wald National Park benefited the local community by collaborating with them to develop unique tourism projects. This model, which combines culture with tourism, not only enriches tourists’ travel experience but also provides considerable economic returns for community residents [24]. Serengeti National Park in Tanzania has adopted a joint management arrangement, strengthened community participation, and directly improved the education level and health safety level of residents [28]. Numerous studies have shown that a community-based conservation policy not only provides an increase in household income but also increases the knowledge utilization rate of community residents, greatly alleviating conflicts between communities and departments responsible for protected area management [57,58].

It can be observed that the global goal of border adjustment is mainly achieved through legal tools or community consultations, and the effectiveness of policy implementation varies. While China’s “sky window” policy emphasizes administrative-led border adjustment, there is still a research gap in terms of its impact on community livelihood outcomes, especially with respect to household income.

2.2. Theoretical Framework

Based on the sustainable livelihoods framework (SLF), this study explored the impact of the “sky window” policy on the livelihood outcomes of residents in national park communities. This theoretical framework, first proposed by the Department for International Development (DFID), elaborates on the key factors influencing people’s livelihoods and constructs the roles and connections between livelihood capital, strategies, and outcomes [59]. Specifically, the framework categorizes livelihood capital into five types: natural capital, human capital, financial capital, social capital, and physical capital. Natural capital mainly refers to the land area owned or operated by a household, including arable land and forest land [60,61]. Human capital generally refers to the number of household members and their educational attainment, the age of household members, and whether there is a Communist Party member in the household [61,62]. Financial capital mainly includes household loans, savings, investments and wealth management products, etc. [63]. Social capital is often measured by interpersonal relationships and membership in certain institutions or organizations [61,62,63]. Physical capital is usually represented by the accessibility of infrastructure and equipment, such as factory buildings and residential property [62,63,64]. The availability of these livelihood capitals directly affects the choices and decisions of household livelihood strategies. People ensure survival by optimizing the combination of various livelihood capital they possess while also being impacted by various policy factors [59,60].

Specifically, community residents within national parks generally integrate different types of livelihood capital through various agricultural and non-agricultural activities to obtain household income [61]. It is worth noting that different policy variables often have a significant impact on livelihood outcomes. To solve a series of problems caused by land resource restructuring during the construction of national parks and to further alleviate the contradiction between ecological protection and local community development, the Chinese government has creatively proposed the “sky window” policy, which adjusts the boundaries of national parks and delineates areas that conflict with ecological conservation goals from the administrative jurisdiction of national parks (although they are still within the spatial geographic scope of national parks).

This policy may have a positive effect on optimizing the configuration of space, but it also has a negative impact on the livelihoods of families in the window communities [26,65]. On the one hand, these “window communities” are easily influenced by various inherent factors. In general, these communities often face challenges such as dense population resources, unclear land ownership, and high dependence on natural resources, resulting in conflicts between resource utilization and conservation goals. On the other hand, once these communities are designated as national parks, their living space, employment opportunities, and sources of income are directly threatened [37,42,44]. In addition to the inherent system complexity of window communities, due to the redefinition of the physical boundaries of space via the “sky window” policy, community residents’ legitimate rights to access and utilize natural resources within national parks are restricted to varying degrees, directly leading to a reduction in the natural capital stock of households [44]. Simultaneously, as a result of the administrative separation between these window communities and the national park management system, they lack supportive industrial development measures, vocational training programs, and long-term compensation mechanisms [38,44], which may lead to a short-term decline in household income.

Furthermore, the “sky window” policy may affect farmers’ income in two ways: First, the “sky window” policy eases the restrictive regulations on farmers’ planting and breeding activities within national parks, thereby exerting an impact on the total household income of residents. The “sky window” policy allows farmers to cultivate in national parks. In addition, as national parks impose restrictions on water-intensive and pollution-heavy agricultural activities (such as large-scale breeding and greenhouse farming), farmers are compelled to shift toward low-intensity, eco-friendly production methods (e.g., understory economies). This transition reduces the constraints that the “sky window” measure places on farmers’ engagement in understory planting and breeding. However, such industries are characterized by high initial investment, long payback periods, and significant market risks (e.g., fluctuations in agricultural product prices and limited sales channels) [66], which may result in a decline in farmers’ income in the short term.

Second, constrained by policy frameworks, farmers are less inclined to engage exclusively in agricultural activities and instead show a greater propensity for part-time activities. Without the “sky window” policy, farmers would lose the possibility of cultivating land within the geographical scope of national parks. This policy permits farmers to engage in agricultural activities within national parks, thereby providing them with arable land resources. As a result, farmers can not only carry out agricultural production activities but can also gain access to local employment opportunities. Therefore, the “sky window” policy is conducive to farmers’ part-time employment, which in turn promotes income growth. A substantial body of research suggests that, relative to purely agricultural or purely non-agricultural livelihood strategies, part-time strategies are associated with higher economic returns [67,68]. The theoretical framework of this study is shown in Figure 1.

Based on the above analysis, the following hypotheses are proposed:

Hypothesis 1.

The “sky window” policy may cause a decrease in household income for residents.

Hypothesis 2.

The “sky window” policy eases restrictive regulations on farmers’ planting and breeding activities within national parks, thereby exerting an impact on the total household income of residents.

Hypothesis 3.

The “sky window” policy may induce a shift among farming households toward a part-time model, which would diversify their income structure and enhance their risk resistance capacity, thereby increasing total household incomes.

3. Methodology

3.1. Study Area

Wuyi Mountain National Park is part of the first batch of national parks established in China, with a total area of 1279.82 square kilometers. It boasts the most representative primary mid-subtropical forest ecosystem in the coastal mountains of Zhejiang and Fujian Provinces, and it is the most typical primary mid-subtropical forest ecosystem compared to other global forests at the same latitude. It is also a renowned gene bank of species and a source of biological specimens. Wuyi Mountain National Park not only stands as a paradigmatic representative of mid-subtropical forest ecosystems but also serves as a treasure trove of flora and fauna in the southeast region while being recognized as a dual World Heritage site for both its cultural and natural values; it spans nine townships across four counties (cities and districts) in Nanping City, Fujian Province—namely Wuyishan City, Guangze County, Shaowu City, and Jianyang District—and three townships in Yanshan County, Shangrao City, and Jiangxi Province [69].

As one of the first pilot areas for the national park system, Wuyi Mountain National Park has, since 2017, adopted systematic regulatory measures to adjust the modes of production, living, and resource utilization within its jurisdiction with the aim of balancing the needs of ecological conservation and community development. For example, the national park has set up 11 ecological compensation content types, including compensation for the protection of ecological public welfare forests and compensation for forest right owners [70]. The management of servitude rights has also been implemented, meaning that the ownership of forest land and trees in the bamboo forest remains unchanged, and the National Park Management Bureau has obtained the right to protect and manage them. However, forest farmers are not allowed to engage in business activities, such as harvesting bamboo or digging bamboo shoots, and are given subsidies ranging from CNY 90 to 118 per mu per year [71]. By creating ecological tea gardens and constructing the National Park No.1 Scenic Road, as well as developing an under-forest economy, the national park continues to expand green industries such as tea, tourism, and bamboo. These measures have made important contributions, achieving a “win–win” situation between ecological protection and socio-economic development.

Since the official establishment of national parks in 2021, the institutional development of Wuyi Mountain National Park has been progressively refined. Nevertheless, the construction of the national park has also posed challenges to the development of rural communities within its boundaries. To reconcile the conflict between ecological conservation and community development, the national park has implemented the “sky window” policy, which optimizes the spatial layout by excluding some rural communities from the park’s boundaries. In the case of Wuyi Mountain National Park, due to the scarcity of local arable land resources, the government has implemented strict farmland protection strategies, designating even scattered patches of arable land within the park as sky windows. However, the actual effectiveness of such a measure remains undetermined. Therefore, investigating exactly how this policy has impacted the household livelihoods of residents in communities within Wuyi Mountain National Park holds significant theoretical and practical implications for the future construction of national parks. The study area is distributed as shown in Figure 2.

3.2. Survey Program

A field survey was conducted in Wuyi Mountain National Park in June 2024. Before conducting the survey, we provided the researchers with training. During the half month research period, our interviews with the respondents covered two period dimensions, asking them to retrospect relevant information for the years 2017 and 2023. The survey area covered 22 administrative villages across 9 townships within the national park, including 13 communities in window zones and 9 communities in non-window zones. We selected the villages randomly. For the investigation, rural households were randomly selected from each village. For each selected village, the village cadres were first interviewed to obtain a household register list, from which 15 to 20 households were randomly selected for the survey. A total of 581 households were surveyed via face-to-face interviews. There were a total of 1036 samples in the two data periods. After removing missing data, information from 951 samples was used in the study (

Table 1. Distribution of rural communities and the number of valid samples in Wuyi Mountain National Park.

Region	Classification of Community Types	Observations
Jiangxi region	“window” communities	88
	“non-window” communities	290
Fujian region	“window” communities	402
	“non-window” communities	171
Total		951

).

This study designed three questionnaires with different dimensions, and the survey subjects were the management committee of WMNP, villages, and households. The questionnaire survey of the management committee was completed through discussions with the relevant department staff, and it collected information including the fundamental situation, organizational structure and management system, protection measures, and national park investments. As for the village questionnaire survey, it was conducted through in-depth interviews with village officials, covering the basic population structure; infrastructure construction; various transfer payments, including ecological compensation; community development initiatives; and connections with administrative agencies. The household questionnaire was the focus of this study, and its design was based on the theoretical framework described earlier. The interviewees were mainly household heads. The interview content specifically covered the following: basic information on family members, ownership of five types of livelihood capital, choices of livelihood activities, and household income. The detailed information collected from the sampled households is shown in

Table 2. Descriptive statistics of the total sample.

Variable	Definition	Total		2017		2023		Observations
		Mean	Std. Dev.	Mean	Std. Dev.	Mean	Std. Dev.
The “sky window” policy	Whether the household is located in a “sky window” community (1 = yes; 0 = no)	0.52	0.5	0.52	0.5	0.52	0.5	951
Human capital
Education	Whether the education level of the household head is above junior middle (1 = yes; 0 = no)	0.16	0.36	0.15	0.36	0.16	0.36	951
Age	Age of the household head	53.92	11.93	51.02	11.51	56.81	11.65	951
Party	Whether the household head is a member of the Communist Party of China (1 = yes; 0 = no)	0.14	0.35	0.14	0.35	0.14	0.35	951
Household member	Total household population	4.33	1.67	4.27	1.6	4.39	1.74	951
Physical capital
House value	Log of the value of house property	12.47	2.46	12.32	2.45	12.62	2.46	951
Business	Whether the household has self-operated businesses (1 = yes; 0 = no)	0.48	0.5	0.45	0.5	0.52	0.5	951
Financial capital
Saving	Household savings (1 = household savings of CNY ten thousand or more; 0 = household savings below CNY ten thousand)	0.55	0.5	0.55	0.5	0.55	0.5	951
Loan	Whether there is a loan in the household (1 = yes; 0 = no)	0.26	0.44	0.2	0.4	0.33	0.47	951
Natural capital
Land	Forest land area and farmland area (mu)	40.63	71.14	40.65	71.48	40.6	70.87	951
Social capital
Relationship	How many people usually help in the village during weddings and funerals	36.96	42.06	38.79	43.09	35.13	40.96	951
Losses	Whether there are any losses caused by unexpected events (1 = yes; 0 = no)	0.22	0.42	0.21	0.41	0.23	0.42	951
Region	Family region (1 = Fujian Province; 0 = Jiangxi Province)	0.6	0.49	0.6	0.49	0.6	0.49	951
Off-farm job	Whether there is anyone in the family engaged in off-farm job (1 = yes; 0 = no)	0.88	0.33	0.87	0.34	0.89	0.31	951
Work in NP	Whether there is anyone working in the national park (1 = yes; 0 = no)	0.23	0.42	0.21	0.41	0.25	0.44	951
Income per village	The per capita annual income of the village where the family is located (CNY)	28,246	23,744	28,190	22,508	28,302	24,941	951
Total income	Total income of household (CNY)	259,000	489,000	260,000	555,000	259,000	414,000	951
Farm income	Agricultural income of household (CNY)	4345	26,930	4360	11,584	4331	36,284	951
Off-farm income	Off-farm income of the household (CNY)	254,000	487,000	254,000	555,000	254,000	408,000	951

.

3.3. Model Specification

The difference-in-differences (DID) model is an econometric method based on natural experiments, which evaluate the net effect of policies by comparing the differences between the experimental group and the control group before and after policy shocks, removing confounding factors such as time trends. Its basic idea is based on a counterfactual framework that compares changes in observed variables with and without the implementation of policies. In short, “differencing” means subtraction, and “double differencing” means subtracting twice [72]. In this study, the impact of the “sky window” policy of Wuyi Mountain National Park on community livelihoods (income) was regarded as a quasi-natural experiment. By comparing the differences in household income changes between the experimental group (window community) and the control group (non-window community) before and after policy implementation, the influence of other common factors was eliminated, thus obtaining the net effect of policy implementation.

However, due to the possibility of policy implementation being related to some omitted variables, there may still be endogeneity issues in the use of the DID model, resulting in bias and inconsistency in the estimation results. This study adopted a fixed-effect model to control for time-invariant heterogeneity at the individual level in order to address endogeneity issues. Based on the above analysis, the model used in this study is as follows.

Y_it = α₀ + α₁treat_i × post_t + α₂X_it + μ_i + ν_i + ε_it

(1)

In Equation (1), i denotes the household, and t denotes the period. α₀ is the constant term; Y_it is the explained variable, representing the income of a household in the community. treat_i × post_t is the interaction term between the grouping dummy variable and the policy implementation dummy variable. treat_i is a group dummy variable indicating whether the policy is implemented. If i is affected by policy implementation, then i belongs to the treatment group, and treat_i is assigned a value of 1. If i is not affected by policy implementation, then i belongs to the control group, and treat_i is assigned a value of 0. post_t is a time dummy variable for policy implementation, with a value of 0 before policy implementation and a value of 1 after policy implementation. The “sky window” policy of Wuyi Mountain National Park was officially implemented in 2022. α₁ reflects the net effect of policy implementation, which is also the most important factor we focus on when using DID. X_it denotes the control variables affecting Y_it; α₂ denotes the corresponding coefficients of the control variables, including different livelihood capital and other control variables. μ_i, ν_t, and ε_it represent the individual fixed effects, time fixed effects, and random error terms, respectively.

4. Results

4.1. Descriptive Statistical Analysis Results

Table 3. Descriptive statistics of “window” communities and “non-window” communities.

Variable	Window Communities				Non-Window Communities
	2017		2023		2017		2023
	Mean	Std. Dev.	Mean	Std. Dev.	Mean	Std. Dev.	Mean	Std. Dev.
Human capital
Education	0.18	0.38	0.18	0.38	0.13	0.34	0.13	0.34
Age	50.83	11.82	56.66	11.76	51.22	11.19	56.97	11.56
Party	0.14	0.35	0.14	0.35	0.14	0.35	0.14	0.35
Household member	4.22	1.55	4.34	1.71	4.32	1.65	4.46	1.79
Physical capital
House value	12.62	2.29	12.96	2.03	12.00	2.56	12.25	2.81
Business	0.51	0.5	0.58	0.5	0.38	0.49	0.46	0.5
Financial capital
Saving	0.6	0.49	0.58	0.5	0.49	0.5	0.52	0.5
Loan	0.19	0.4	0.33	0.47	0.2	0.4	0.32	0.47
Natural capital
Land	44.8	79.04	44.28	77.69	36.22	62.3	36.71	62.77
Social capital
Relationship	42.27	51.82	39.51	50.57	35.09	30.92	30.49	26.63
Losses	0.21	0.41	0.27	0.44	0.21	0.41	0.2	0.4
Region	0.82	0.39	0.82	0.39	0.37	0.48	0.37	0.48
Off-farm job	0.85	0.36	0.89	0.32	0.88	0.32	0.9	0.3
Work in NP	0.24	0.43	0.28	0.45	0.18	0.39	0.23	0.42
Income per village	30,245	22,205	36,580	31,358	26,002	22,669	19,522	9545
Total income	324,000	675,000	299,000	448,000	192,000	378,000	216,000	372,000
Farm income	4777	10,209	2682	7297	3914	12,896	6079	51,540
Off-farm income	318,000	676,000	296,000	448,000	185,000	378,000	210,000	357,000

shows the descriptive statistics of window communities and non-window communities. It can be observed that at the household level, from 2017 to 2023, there was no significant change in residents’ educational attainment. However, residents in window communities had a higher level of education than those in non-window communities, and the same pattern was observed in the operation of self-employed industrial and commercial businesses. The value of housing also showed an upward trend, indicating that the series of measures (such as supporting ecotourism and strengthening infrastructure construction) adopted during the construction of the national park effectively increased the physical capital of community residents. In addition, residents in window communities observed a decrease in savings and an increase in loaning, while residents in non-window communities experienced an increase in both savings and loans. Regarding the area of operational cultivated land, residents in window communities had a significantly larger area than those in non-window communities, and the same result was observed in terms of interpersonal relationships. It can also be noted that the number of residents working in the national park increased in both window and non-window communities, with a larger number observed in window communities compared to non-window communities.

At the community level, from 2017 to 2023, the per capita income of villages in window communities increased significantly from CNY 30,245 to CNY 36,580, while that in non-window communities showed a downward trend, decreasing from CNY 26,002 to CNY 19,522. In terms of income levels, the total household income, agricultural income, and non-agricultural income in window communities were all higher than those in non-window communities, but they all exhibited a downward trend, whereas the household income in non-window communities exhibited an increase.

The above results indicate that window communities are superior to non-window communities in terms of human capital, natural capital, and household income, but they mostly exhibited a downward trend after the implementation of the “sky window” policy.

4.2. Baseline Regression Results

To examine the impact of the demarcation of window communities in the national park on farmers’ household income, this study uses the implementation of the window community demarcation as a variable to represent the “sky window” policy, aiming to assess its relationship with household income. Based on the application of the DID model, this study controlled for double fixed effects, including individual fixed effects and time fixed effects, and we obtained the baseline regression results (see

Table 4. Baseline regression results of the impact of the demarcation of national park window communities on farmers’ total income.

Variables	(1)	(2)	(3)
	Total Income	Farm Income	Off-Farm Income
The “sky window” policy	−0.106 *	−1.219 ***	−0.126 *
	−0.057	−0.454	−0.066
Constant	10.252 ***	6.464 ***	9.947 ***
	−0.71	−5.019	−0.84
Controlled variables	YES	YES	YES
Individual fixed effects	YES	YES	YES
time fixed effects	YES	YES	YES
Observations	951	951	951
R-squared	0.936	0.869	0.926

Robust standard errors in parentheses; *** p < 0.01, ** p < 0.05, and * p < 0.1.

). The results indicate that the demarcation of window communities in Wuyi Mountain National Park exerted a statistically significant negative impact on farmers’ total household income at the 10% significance level. Regarding the impact of the “sky window” policy, previous studies found that the policy resulted in the fragmentation of protected areas and hindered the development of community economy [47]. In addition, residents of window communities insisted that they had adverse effects on family production and life [44,48]. The research results of this paper are consistent with these research conclusions.

Specifically, compared with non-window communities, the total household income of farmers in window communities decreased by CNY 0.106, validating Hypothesis 1. Furthermore, it can be observed that the demarcation of window communities in the national park also exerted significant negative impacts on both agricultural income and non-agricultural farmer household incomes, with statistical significance at the 1% and 10% levels, respectively.

4.3. Robustness Analysis

To ensure the reliability and robustness of the empirical results, this study conducted robustness tests on the model by employing propensity score matching (PSM) followed by regression analyses. As shown in

Table 5. Results of the PSM-DID robustness test on the impact of the “sky window” policy on farmers’ total income.

Variables	Total Income			Farm Income			Off-Farm Income
	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
	Radius	Kernel	Nearest Neighbor	Radius	Kernel	Nearest Neighbor	Radius	Kernel	Nearest Neighbor
The “sky window” policy	−0.108 *	−0.106 *	−0.106 *	−1.328 ***	−1.303 ***	−1.219 ***	−0.129 *	−0.124 *	−0.126 *
	−0.061	−0.058	−0.057	−0.469	−0.457	−0.454	−0.071	−0.067	−0.066
Constant	10.859 ***	10.368 ***	10.252 ***	6.394	7.246	6.464	10.381 ***	10.036 ***	9.947 ***
	−0.78	−0.729	−0.71	−5.817	−5.242	−5.019	−0.96	−0.869	−0.84
Controlled variables	YES	YES	YES	YES	YES	YES	YES	YES	YES
Individual fixed effects	YES	YES	YES	YES	YES	YES	YES	YES	YES
time fixed effects	YES	YES	YES	YES	YES	YES	YES	YES	YES
Observations	908	940	951	908	940	951	908	940	951
R-squared	0.938	0.936	0.936	0.876	0.87	0.869	0.927	0.925	0.926

Robust standard errors in parentheses; *** p < 0.01, ** p < 0.05, and * p < 0.1.

, the regression results obtained via radius-matching, kernel-matching, and nearest-neighbor-matching methods for re-matching are consistent with those presented earlier, confirming that the “sky window” policy exerted a significant negative effect on farmers’ household income. This further validates the robustness of the empirical findings of this study.

4.4. Mechanism Analysis

To further analyze the specific pathways through which the “sky window” policy affects farmers’ household income, two mechanism variable categories were selected (

Table 6. Results of mechanism analysis on the impact of the “sky window” policy on farmers’ household income—DID.

Variables	Whether There Are Restrictions on This Type of Activity (1 = yes; 0 = no)		Livelihood Strategy
	Understory Planting	Understory Breeding	Whether the Household Is Part-Time (1 = Yes; 0 = No)
The “sky window” policy	−0.022 *	−0.030 **	−0.001
	−0.012	−0.012	−0.025
Constant	0.833 ***	1.280 **	−0.384
	−0.112	−0.414	−0.492
Controlled variables	YES	YES	YES
Individual fixed effects	YES	YES	YES
Time fixed effects	YES	YES	YES
Observations	951	951	951
R-squared	0.982	0.979	0.914

Robust standard errors in parentheses; *** p < 0.01, ** p < 0.05, and * p < 0.1.

). The first category comprises restrictive behaviors, including understory planting and understory breeding; the second category refers to livelihood strategies, specifically whether a household engages in multiple occupations (i.e., part-time household). The results indicate that the “sky window” policy reduces restrictions on farmers’ understory planting and understory breeding activities within the national park, resulting in a significant decline in their income, which validates Hypothesis 2. The “sky window” policy has reduced restrictions on households’ understory planting and understory breeding activities within the national park, resulting in a decline in their income. This reduction may be caused by the relaxation of planting restrictions, which has allowed farmers to expand and intensify their agricultural production. Furthermore, such industries are characterized by high initial investments, long payback periods, and substantial market risks, which may result in short-term income downturns.

The “sky window” policy exerted no significant impact on household income through part-time activities, which is inconsistent with Hypothesis 3. This can be attributed to the fact that the policy merely adjusts the spatial boundaries of the national park without directly involving the development of non-agricultural industries, changes in employment policies, adjustments to land contracting relationships, or mandatory modifications to farming practices. As land ownership remains unchanged, farmers still retain management rights to their original land and can independently decide the level of agricultural input or choose to transition to non-agricultural employment. Consequently, the “sky window” policy does not induce a transition of farming households to part-time households, nor does it exert a significant influence on livelihood strategies.

4.5. Heterogeneity Analysis

According to the above analysis, the “sky window” policy has resulted in a decrease in farmers’ household income. With this being the case, we further examine the differences in this impact across different groups.

Table 7. Results of heterogeneity analysis—DID.

Variables	The Household Head Is not a Member of the Communist Party of China	The Household Head Is a Member of the Communist Party of China	Household Savings Below CNY 10,000	Household Savings Above CNY 10,000	The Land Area Is Below the Average Level	The Land Area Is Above the Average Level	There Are no Elderly Members Aged 60 and Above in This Household	The Household Has Elderly Members Aged 60 and Above
	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
The “sky window” policy	−0.107 *	0.018	0.09	−0.136 *	−0.016	−0.118	−0.244 **	−0.079
	−0.06	−0.179	−0.098	−0.079	(0.081)	(0.081)	(0.117)	(0.087)
Constant	10.460 ***	11.396 ***	10.627 ***	10.984 ***	9.548 ***	10.809 ***	12.171 ***	9.264 ***
	−0.477	−2.069	−0.864	−1.481	(0.677)	(0.997)	(2.124)	(1.019)
Controlled variables	YES	YES	YES	YES	YES	YES	YES	YES
Individual fixed effects	YES	YES	YES	YES	YES	YES	YES	YES
Time fixed effects	YES	YES	YES	YES	YES	YES	YES	YES
Observations	817	134	430	521	474	477	441	510
R-squared	0.936	0.947	0.935	0.947	0.934	0.942	0.923	0.964

Robust standard errors in parentheses; *** p < 0.01, ** p < 0.05, and * p < 0.1.

presents the results for different groups. It can be observed that for non-party-member households, the “sky window” policy exerts a significantly negative impact on their income, illustrating the crucial role of human capital in improving income levels. Furthermore, for households with high savings, the “sky window” policy also significantly reduces their income levels. This may be attributed to the fact that households with higher savings tend to adopt conservative investment strategies, especially for those with relatively older household heads in national parks, which are not conducive to income improvement [73,74]. The policy also exhibits a significant negative impact on income for households operating on relatively large land areas, which may be attributed to the fact that the “sky window” policy allows residents to access more natural resources, resulting in a decrease in their enthusiasm for non-agricultural production. This further results in a single channel for increasing income and ultimately lowering their income levels. In addition, the policy has a greater impact on young and middle-aged families, causing a decrease in their household income. Due to the implementation of the “sky window” policy, young adults are more inclined to stay in the local area and reduce the diversified livelihood strategy of working outside, which makes the income structure more singular and leads to a decrease in income.

5. Discussion

The “sky window” policy is regarded by national parks as an effective ecological governance tool for protecting the natural environment, and its implementation has intensified against the backdrop of ecological redline adjustments [38]. However, an overemphasis on ecological protection goals while neglecting the sustainability of community development essentially fails to truly realize the government’s vision of the harmonious coexistence of humans and nature. By quantitatively analyzing farmers’ livelihood outcomes, this study systematically evaluates the impact of the “sky window” policy on farmers’ total income in Wuyi Mountain National Park. The “sky window” policy implemented in Wuyi Mountain National Park has been observed to result in a reduction in farmers’ incomes. This result may be explained by various factors, as shown through analysis of the data in the previous sections and the in-depth interviews with important interviewees, such as management departments and village cadres.

5.1. There Is a Structural Contraction in Resource Utilization Rights

Although the geographical space of “window” communities remains within the national park, the policy adjustment of “being excluded from the national park boundary” deprives them of the flexibility in resource utilization that they previously enjoyed within the original protected area [37,38]. Although the “sky window” policy theoretically relaxes certain restrictions, the livelihood activities traditionally relied upon by these communities (such as understory planting and traditional breeding) are, in practice, subject to dual constraints, resulting in a decline in their income. This reduction may be caused by the relaxation of planting restrictions, which has allowed farmers to expand and intensify their agricultural production. Furthermore, such industries are characterized by high initial investments, long payback periods, and substantial market risks, which may result in short-term income downturns. Further, as their geographical space still belongs to the national park, resource development activities must meet higher ecological thresholds (e.g., pollution control, scale limitations), which reduces the profit margins of the original production models [41,42,44]. Furthermore, after being excluded from the boundaries of the national park, some communities are no longer included in the ecological compensation and industrial support systems of the national park (such as special subsidies and technical training), resulting in an increase in resource acquisition costs (e.g., agricultural input procurement, production licensing) without a corresponding increase in returns.

5.2. The Household Income Is Influenced by the Discontinuity Effect and Lagging Supporting Measures in Livelihood Transition

As mentioned earlier, “window” communities are typically characterized by “a strong dependence on natural resources and a weak economic foundation” [41,42]. The period from 2017 to 2023 coincided with the institutional reform stage of the national park, During this period. After the implementation of the “sky window” policy, the original livelihood models of the communities that relied on national park resources (such as conservation-compatible agriculture and tourism-supporting services) were weakened due to policy adjustments. Simultaneously, new alternative livelihood models (such as non-agricultural employment and market-oriented industries) have been slow to develop due to the lack of supporting measures, including vocational training and credit services, resulting in a sharp reduction in residents’ income channels [75]. When residents’ farmlands were excluded from the protected area, the government failed to provide timely and effective guidance on agricultural transformation and financial support. Many residents lack training in ecological tourism services, and the area’s underdeveloped tourism infrastructure fails to attract a sufficient number of tourists, resulting in extremely limited income from the tourism industry [38,42]. Furthermore, the ecological compensation mechanism, a crucial support measure, has not been effectively implemented in the national park. The traditional livelihood model of the “window” community was damaged and lacks new livelihood models, ultimately resulting in a decline in income.

5.3. Imperfect Laws Resulted in a Lack of Protection of Rights and Interests

Currently, there are still several areas in the legal system of national parks in China that need to be improved. This not only hinders the protection of the rights and interests of residents in park communities but also directly affects their economic income status [76,77]. Firstly, there are ambiguous areas in current laws and regulations regarding the definition of core rights, such as residents’ land rights and resource utilization rights. In the process of promoting the “sky window” policy, residents have always lacked clear legal standards as a basis for judging whether their land and resources have been reasonably delineated for protection and whether their legitimate rights and interests have been fully protected. For example, when some residents’ homesteads or contracted land is included in the adjustment scope, due to the unclear definition of the land acquisition process and compensation standards in the law, residents are often prone to being passive and unable to obtain economic compensation that matches their losses [78]. Secondly, there is no clear legal regulation on the mechanism for coordinating interests between national park management agencies and community residents. In the process of policy implementation, management agencies often overlook the development demands of community residents due to excessive focus on ecological protection goals [42]. When residents experience a decline in income due to protection policies, they often lack accessible legal channels to safeguard their rights, and they encounter numerous legal barriers when exploring new sources of income, which limits their potential for income growth.

5.4. The Marginalization of Market Access and Value Realization Indirectly Affected the Welfare of Residents in National Park Communities

Upon being excluded from the protected area’s boundary, products from window communities (such as agricultural products and handicrafts) lose the premium brand associations, such as “National Park Origins”, and unified marketing channels (e.g., national-park-led e-commerce platforms) [79]. The community also loses the brand effect of the national park, directly affecting the development of the community’s ecological tourism industry [38,41,42]. At the same time, as their geographical space remains within the national park, their production activities must bear additional costs for ecological compliance (such as environmental certification). However, they are unable to share the market resources of the national park, resulting in damage to welfare benefits. In addition, due to not being under the jurisdiction of national parks, local communities are often prone to the dilemma of weak local leadership, resulting in a lack of development vitality and financial support.

5.5. The Severe Impact of COVID-19 on the Income of Residents in National Park Communities

Communities in the national park are highly reliant on ecotourism and its derivative services. During the pandemic, the closure of scenic spots and a sharp decrease in tourist flow directly led to the shutdown of homestays, tour guide unemployment, and the breakdown of related income chains [80]. Simultaneously, the community’s characteristic agricultural products are mostly sold directly through tourism channels. The pandemic disrupted offline transactions, while logistical restrictions hindered online sales, resulting in unsold and overstocked agricultural products and heavy losses for farmers. Handicraft production and ecological experience programs that rely on national park resources also came to a complete halt, exacerbating the already simplistic income structure. In addition, pandemic prevention and control measures increased operational costs, while the slow recovery of tourist flows after reopening kept residents’ income depressed, affecting even their basic livelihoods [81,82].

The findings of this study have profound policy implications. Given the short duration of the “sky window” policy’s implementation and its insufficient operational timeframe, many supporting measures remain underdeveloped, resulting in a short-term decline in income. Nevertheless, from a long-term perspective, there is ample room for optimizing policy design, which will, in turn, contribute to income-level improvements.

In the future, efforts should primarily focus on the following aspects. First, laws and regulations governing national park construction should be further improved. During legislative revisions, the scope, standards, and procedures of the “sky window” policy should be clarified, with clear definitions of areas suitable for such measures and the ecological, social, and economic conditions required. For instance, in relevant regulations such as the National Park Law, detailed provisions should be formulated for the “sky window” in specific scenarios, including permanent basic farmland and artificial commercial forests. It is also necessary to clarify the management subject and responsibilities of window communities. At the same time, a dynamic assessment mechanism should be established to conduct regular reviews of the policy effects of the “sky window”, with timely adjustments carried out based on changes in the ecological environment of national parks and the development needs of local communities. Furthermore, the alignment between different regulations should be strengthened to ensure that the “sky window” policy is coordinated and unified within the regulatory framework, including territorial spatial planning and ecological protection redline management, avoiding contradictions and conflicts and thereby enhancing the overall effectiveness of the policy.

In addition, from the perspective of the residents, the national park should facilitate income improvement through four approaches: First, the national park should strengthen cooperation with local communities by establishing a normalized collaboration mechanism that includes management agencies, community representatives, and ecological/planning experts. Priority can also be given to providing positions such as forest rangers and guides to jointly develop ecological products and feedback profits, thus building a benefit sharing model. Second, a platform for realizing the value of ecological products should be established. For example, community handicrafts and organic agricultural products can be incorporated into the national park’s brand certification system and marketed through unified e-commerce platforms and cultural and creative tourism stores. Third, support for livelihood transitions should be enhanced by providing targeted training tailored to residents’ different skill levels, such as homestay management and ecological agriculture techniques, which could be accompanied by microcredit and entrepreneurship subsidies to reduce barriers to transitions. Furthermore, it is necessary to establish a long-term interest linkage mechanism, allocating a certain proportion of tourism revenue to community development funds for residents’ dividends and public service improvement; this would further improve the franchising of national parks, and the participation of community residents in park management, cleaning, and other operations could be prioritized to ensure a stable source of income.

6. Conclusions

This study employed the DID model to quantitatively evaluate the impact of the “sky window” policy on the income levels of community farmers in the context of national park construction. The theoretical significance of this study lies in two aspects: on the one hand, it enriches the existing literature on the impact of the “sky window” policy in national parks and fills some gaps in this field of research; on the other hand, it expands the research scope of the sustainable livelihood framework and offers a brand-new research perspective for the expanded application of this theory in the field of national parks. The major conclusions of this study are as follows.

The demarcation of window communities in Wuyi Mountain National Park exerted a statistically significant negative impact on farmers’ total household income at the 10% significance level. Specifically, compared with non-window communities, the total household income of farmers in window communities decreased by CNY 0.106. The demarcation of window communities in the national park also exerted significant negative impacts on both the agricultural and non-agricultural income of farmers’ households.

The “sky window” policy relaxed restrictions on households’ understory planting and breeding activities within the national park, resulting in a decline in their income, which may be due to the relaxation of planting restrictions, which allowed farmers to intensify their agricultural production. However, such industries are characterized by high initial investments, long payback periods, and substantial market risks, which may result in short-term income downturns. On the other hand, the “sky window” policy had no significant impact on household income through part-time activities.

The “sky window” policy had a significant negative impact on the income of non-party-member households, further illustrating the crucial role of human capital in improving income levels. Furthermore, the “sky window” policy significantly reduced the income levels of households with large savings. The policy also had a significant negative impact on the income of households operating on relatively large land areas, which may be attributed to the fact that it allows residents to access more natural resources, leading to a decrease in their enthusiasm for non-agricultural production, thus resulting in a single channel for increasing income and ultimately lowering their income levels. Additionally, the policy had a greater impact on young and middle-aged families, resulting in a decrease in their household income. Due to the implementation of the “sky window” policy, young adults are more inclined to stay in the local area, reducing the diversified strategy of working outside for their livelihood, which makes the income structure more singular and leads to a decrease in income.

In the future, we recommend the following for improving policy implementation in national parks: First, the laws and regulations on the construction of national parks should be improved. Second, a dynamic evaluation mechanism should be established. In addition, coordination between different regulations should be strengthened to ensure that the “sky window” policy is coordinated and unified within a regulatory framework. From the perspective of residents, income growth can be achieved through the following measures: establishing a platform for realizing the value of ecological products, enhancing support for livelihood transformation, establishing a long-term interest linkage mechanism, and further improving the concessionary operation mechanism of national parks to secure a stable source of income.

We acknowledge that this study has shortcomings. First, the survey focused only on Wuyi Mountain National Park and lacks empirical data from other national parks, which imposes certain limitations. Additionally, the data analyzed is retrospective and may have a certain degree of subjectivity, leading to limitations in the research conclusions. Moreover, our research lacks detailed information on the livelihood strategies employed by local communities to offset income losses; this information could have increased the depth of the study. Furthermore, we only conducted short-term surveys on two sets of data. The results are limited due to various factors, such as insufficient infrastructure and policy support in the short term. A long-term investigation is necessary and will be of great value in understanding the possible changes in household income over time. In response to these two shortcomings, we need to enrich the questionnaire content further, conduct long-term surveys, and comprehensively explore the results in the future in order to provide more targeted insights for management authorities.