1. Introduction
In recent years, with the frequent occurrence of natural disasters, the scenic area system has been hit hard and seriously threatened tourism development [
1]. On 8 August 2017, the Jiuzhaigou earthquake was China’s first earthquake disaster, with its epicenter in the World Natural Heritage site. The magnitude was as high as seven on the Richter scale [
2]. The earthquake was another major natural disaster the Jiuzhaigou scenic area encountered after the “5·12” Wenchuan earthquake in 2008 [
3,
4]. The superimposition of two earthquakes in ten years caused severe damage to some usual scenic spots in Jiuzhaigou’s scenic area, and the hidden dangers of geological disasters became prominent. The post-earthquake recovery and reconstruction task of Jiuzhaigou is arduous. The Sichuan Provincial Government has formulated the “8·8” Jiuzhaigou Earthquake Recovery and Reconstruction Master Plan for the post-disaster recovery and reconstruction work’s overall guidance. The planning period is 2017–2020. Unique implementation plans mainly include environmental restoration and protection, geological disaster prevention, infrastructure and public service reconstruction, urban and rural housing restoration and reconstruction, scenic restoration and upgrading, and industrial development. These planning plans guide the post-disaster restoration and reconstruction of the Jiuzhaigou scenic area [
5]. Since the plan’s implementation, the scenic area has completed the ecological environment restoration in crucial areas and opened in 2020. To understand the current situation and monitor the work’s progress, it is necessary to promptly monitor and evaluate the restoration and reconstruction of the disaster area to find problems in the restoration and reconstruction and propose corresponding solutions. Restoration and reconstruction assessment of disaster areas is a comprehensive evaluation of the effectiveness in the affected areas, in order to understand the effectiveness of restoration and reconstruction implementation as well as any problems, which is conducive to better restoration and construction of the affected areas and to achieve their sustainable development [
6,
7].
Resilience is an emerging concept in the field of disaster management. Its application range extends from the original engineering field to ecological and social areas and has experienced engineering resilience, ecological resilience, and social resilience. These developments have gradually enriched the connotation of resilience [
8,
9]. Resilience in disaster management generally refers to the ability of systems and communities exposed to risks to practically resist, absorb, and adapt to threats, maintain their basic structure and functions and recover from disasters [
10]. At present, resilience research in the social field focuses on the resilience of urban communities. Scenic spots are regional places with corresponding tourist facilities and tourism services in the social ecosystem. There needs to be more research on the resilience development of scenic spots [
11]. Existing scenic area studies are mostly special studies for its earthquake disaster or scenic area sustainable development, this study is more systematic based on scenic area earthquake disaster and landscape analysis before and after restoration and reconstruction to propose a resilience enhancement path. The scenic spot’s resilience emphasizes the ability of the scenic spot system to resist disasters without overly relying on external forces to carry out self-regulation and recovery in combination with its own resources and environmental characteristics [
12]. Scenic resilience discusses a disasters’ impact on the scenic system from an innovative perspective and provides new ideas for disaster management and sustainable development of scenic spots. Improving the resilience level of scenic spots will reduce the region’s vulnerability [
13]. Establishing a framework system for the resilience development of scenic spots and exploring complementary strategies to enhance the resilience of scenic spots is conducive to promoting sustainable tourism development [
14].
The Jiuzhaigou scenic area is the first nature reserve in China whose primary purpose is to protect natural scenery. It includes tourist resources such as mountain lakes, waterfalls, colorful forests, snow peaks, blue ice, and Tibetan customs. The 108 mountain lakes in the scenic area have formed the most representative lake landscape and are also the typical landscape severely damaged by earthquakes. The Jiuzhaigou earthquake destroyed the landscape in the picturesque area but also promoted the reconstruction of the landscape. For example, the earthquake caused damage to the Sparks Sea but produced a new scenic spot called Shuanglonghai Waterfall [
15]. Therefore, post-disaster restoration and reconstruction of scenic spots need to focus on natural restoration, using post-earthquake geological changes to carefully cultivate new landscapes, and at the same time, through conducting scenic restoration and reconstruction monitoring and evaluation, comprehensively improving the quality of scenic restoration and reconstruction [
16]. Traditionally, the monitoring and evaluation of the restoration and reconstruction of disaster-stricken areas are mainly based on tracking statistics, and there are problems such as large survey workloads and difficulties in data collection. However, remote sensing technology is more effective for monitoring and evaluating post-disaster restoration and reconstruction of particular landscape types, such as the World Natural Heritage combined monitoring. The problems found in the evaluation are conducive to studying sustainable tourism development strategies [
17]. This study uses high-resolution remote sensing images to compare the state of some severely damaged lakes before and after the earthquake, analyzing the post-disaster Jiuzhaigou lake landscape reconstruction process, and combines the evaluation results to further explore the resilience development path of the scenic spot under the “Build Back Better” (BBB) concept. Finally, this study may reference the sustainable development of post-disaster tourism in the World Natural Heritage scenic area.
3. Results
3.1. Analysis of Lake Landscape Restoration and Reconstruction
Through the comparison and analysis before (1 July 2017) and after (16 August 2017) the disaster of the four lake landscapes in the Jiuzhaigou scenic area, including the Jianzhu Sea, the Sparks Sea, the Panda Sea, and the Wuhua Sea, the remote sensing images of the lake landscape was compared and analyzed. The damage was monitored and evaluated. It can be seen from
Figure 2 that after the earthquake, steep slopes, and secondary disasters, such as landslides and mudslides, caused vegetation damage, and the lake water level, water quality, flow rate, and travertine deposition rate were all affected. As a result, a large amount of lake water was lost or covered by silt, increasing the silt content, turning the water body yellow, and reducing the lake landscape’s effect. Additionally, the earthquake caused damage to the vegetation in the hilly areas around the lake and the road facilities along the lake, causing heavy losses to the landscape resources. Through comparative analysis of the remote sensing images, it was found that the vegetation on the north and west sides of the Jianzhu Sea was seriously damaged, and the sightseeing roads along were also damaged to some extent. The Sparks Sea was the most severely damaged lake landscape. The south-west side of the Sparks Sea was filled with silt, causing a significant rupture, and the lake’s water level dropped considerable. The vegetation around the Panda Sea was seriously damaged, the vegetation coverage declined, the lake turned yellow, and the sightseeing road on the east side was blocked. The vegetation on the south side of the Wuhua Sea was seriously damaged, and the sightseeing road on the south side was blocked.
After further analysis of the restoration and reconstruction of the four lakes and landscapes at different times (19 April 2018 and 22 May 2019) after the disaster, it was found that the road facilities were first restored and reconstructed within eight months after the disaster, and regular traffic was restored. The Jianzhu Sea, Panda Sea, and Wuhua Sea, after the surrounding damaged roads were restored and reconstructed, still had low vegetation coverage rates. Damaged lakes, such as the Sparks Sea, had not yet been effectively repaired, and the lake landscape’s effect needed to be improved. As of May 2019, the lake landscapes of the Jiuzhaigou scenic area has been restored, and road facilities have returned to normal. The vegetation in the surrounding area has recovered more obviously. The vegetation on the north side of the Jianzhu Sea, around the Panda Sea, and the south side of the Wuhua Sea has been moderately restored.
Furthermore, the water body of the lake has been further improved. The dry lake in the south of the Jianzhu Sea has been filled. The lake, located on the southwest side of the Spark Sea, has been repaired but without its original appearance because of the severe damage. The Panda Sea and Wuhua Sea have also been moderately managed, the lake has become more apparent, and the overall landscape effect has been significantly improved.
3.2. Lake Landscape Composition and Cause Analysis
The Jiuzhaigou lake landscape was formed under specific geological and geographical conditions. The formation of these landscapes is affected by many factors (
Table 3). The geological structure has thick limestone with good permeability, and the rock formations are compressed faults. The development of folds, fractures, and joints promotes underground water infiltration. Secondly, the height difference between the mountain peak and the valley is significant, promoting the formation of travertine deposits in the groundwater exposed in the valley under the effects of temperature and pressure. Furthermore, the CO
2 generated after the decomposition of the vegetation around the lake promotes the increase in carbonic acid in the water. The abundant microbial photosynthesis also enables the supersaturation of calcium carbonate to form travertine deposits [
22].
Additionally, lake water quality becomes better and increases the color gradation due to the high transparency of the lake water, coupled with the selective absorption and reflection of the perspective light by the grey-white travertine and yellow-green algae at the bottom of the lake. The lake water has a low sand content. There are 13 types of lake plant communities, an incomplete ecological community series, and a simple community structure (
Table 4). These vegetation characteristics promote the diversification of the lake landscape [
23,
24].
3.3. Landscape Index Analysis
3.3.1. Basic Landscape Parameters
It can be seen from
Table 5 that during the restoration process from before the disaster to the two years after, the landscape pattern of the four lakes has undergone significant changes. After the catastrophe (16 August 2017) compared with the pre-disaster (1 July 2017), bare land in the four lake areas dramatically increased, while forest land, water bodies, and construction land decreased to varying degrees. Among them, forest land occupied the most significant area, constituting the great change between the two time points.
Further discussion on the recovery and reconstruction situation two years after the disaster (19 April 2018 and 22 May 2019) found that most areas restored regular transportation facilities within eight months. However, the vegetation coverage rate was still at a low level, due to the recurrence of mudslides, thus increasing the area of bare land. However, the vegetation coverage rate increased to varying degrees, as seen from relevant data two years after the disaster. The proportion of forest land in the Sparks Sea area increased by 8%, and more obvious restoration results have been achieved. However, there is still a certain degree of gap before the earthquake.
3.3.2. Patch Density Index
Table 6 shows that the patch density indexes of different land types in the four lake landscapes after the earthquake mostly declined. One year after the post-disaster restoration and reconstruction (2018), the patch density indexes of woodland, water area, and bare land continued to decline while construction land increased. Two years after the post-disaster restoration and reconstruction (2019), the patch density indexes of various land types gradually increased. Among them, the Wuhua Sea showed more apparent changes in its landscape than the other three lakes.
3.3.3. Fragmentation Indexes
Table 7 shows that in the same area and the same year, most of the four landscapes had the highest fragmentation index, indicating that the fragmentation degree was relatively strong. The fragmentation indexes of the different regions and landscape types were equal two years after the disaster (2019). There were different degrees of reduction, which means that the fragmentation decreased over time and the waters and vegetation were restored. The impact of earthquake damage and reconstruction can be seen by classifying the woodland, water area, bare land, and construction land, especially for the woodland and bare land. The water landscape of the Wuhua Sea was even restored its pre-disaster level to a level close to zero.
5. Discussion and Conclusions
5.1. Discussion
5.1.1. The Jiuzhaigou Scenic Area after the Disaster Restoration and Reconstruction of the Dynamic Monitoring Approach Based on the More Diversified Actual Needs
The Jiuzhaigou scenic area is high in the south and low in the north, with deep valleys and vast differences in elevation. There are problems, such as an extensive survey workload and difficulties in data collection for post-disaster recovery and reconstruction monitoring. The high-resolution remote sensing satellite images in this paper facilitate the monitoring of post-disaster recovery and reconstruction to a certain extent but monitoring the lake landscape and other elements need to be further combined with manual field surveys and relevant instruments for water quality testing. At the same time, it is necessary to conduct more microscopic monitoring and identification with the help of drones for areas that are difficult to cover by high-definition remote sensing satellite images. It is necessary to combine various forms of field exploration and sensor monitoring to identify landslides and other potential mountain geological disaster sites and the composition of biodiversity after the disaster. In this paper, post-disaster restoration and reconstruction monitoring methods were proposed. Based on these methods, research can combine with actual cases to verify the various methods’ effectiveness and suitable environments and finally provide technical guidance for the dynamic monitoring of post-disaster restoration and reconstruction in disaster-prone scenic areas.
5.1.2. The Jiuzhaigou Scenic Area Post-Disaster Recovery and Reconstruction Effect Evaluation System Refined Based on Land Type
The Jiuzhaigou scenic environment is characterized by a complex ecological environment and frequent disaster risks, and the earthquake caused significant damage to the surrounding vegetation, water bodies, and tourism facilities. Through restoration and reconstruction, the fragmentation indexes of the different landscape types have been reduced by differing degrees, and the landscape has been moderately restored. However, the vegetation cover in some areas needs to be improved. By analyzing remote sensing images of the Jiuzhaigou scenic area, it is possible to understand the shortcomings of the restoration and reconstruction of forest land, water bodies, bare land, and construction land. Nevertheless, due to the differences between the different land types, a more specific evaluation system can be constructed by combining various types of land in order to propose targeted improvement measures. In addition, there is a need to balance the relationship between ecological restoration and the repair of tourism facilities post-disaster [
50]. The construction of external tourism facilities has, to a certain extent, contributed to the challenges of ecological restoration in the scenic area post-disaster, and subsequent evaluation needs to consider the potential impact of these facilities on the ecological environment. This study focused on the restoration and reconstruction analysis in conjunction with the changes in the lake landscape. Specific evaluation of the restoration and reconstruction effects of the different land types, such as natural vegetation and tourism facilities, is pending to provide a more systematic understanding of the effectiveness of post-disaster restoration and reconstruction.
5.1.3. Geological Disaster-Prone Scenic Areas Need to Integrate the Synergistic Relationship between Post-Disaster Recovery and Reconstruction and Development Revitalization
The Jiuzhaigou scenic area experienced the “5·12” Wenchuan earthquake in 2008 and the “8·8” Jiuzhaigou earthquake in 2017, and the two consecutive earthquakes have made the geological hazards of the scenic area more prominent. In this process, it is necessary to coordinate the intrinsic links between restoration and reconstruction and development revitalization, ensuring that the limited funds and materials are sufficient to complete restoration and reconstruction while promoting the development and revitalization of scenic spots to the greatest extent. This study combined the post-disaster reconstruction experience of some scenic spots in the “5·12” Wenchuan earthquake. It attempted to build a World Natural Heritage scenic spot with more tourism and ecological value after the disaster by integrating the recovery and reconstruction into developing and revitalizing scenic spots. If the scenic area is blindly rebuilt after the disaster, the deterioration of the scenic ecosystem will only intensify. The scenic area’s process of restoration and reconstruction should be based on natural recovery, supplemented with artificial intervention, and to explore the scenic area’s mode of restoration and reconstruction. There needs to be more research on the relationship between restoration and reconstruction and the development and revitalization of scenic spots. The post-disaster restoration and reconstruction planning of World Natural Heritage scenic spots can be in conjunction with the concept of “black tourism”. This strategy focuses on the ecological planning of black tourism resources to meet the emotional experience of tourists to memorable scenes such as earthquake disasters and environmental evolution. Integrating recovery and reconstruction with development and revitalization through various forms can realize the efficient use of resources and the sustainable development of the region.
5.1.4. Post-Disaster Resilience Development Mechanisms of Geological Disaster-Prone Scenic Areas Needs to Be Further Transformed with Regional Characteristics
The dynamic monitoring and comprehensive evaluation of the post-disaster restoration and reconstruction of the Jiuzhaigou scenic area are conducive to exploring the resilience development mechanisms of geological disaster-prone scenic areas. Due to differences in World Natural Heritage scenic areas in various types of geological hazard-prone areas, it is necessary to make appropriate adjustments to the resilience development measures proposed in this study. Furthermore, to meet the development needs of specific scenic areas, the resource environment and disaster risk characteristics of the scenic areas need to be taken into account. Jiuzhaigou’s remote sensing image analysis showed that the lake water body, surrounding vegetation, and supporting facilities still need to be improved. The development mechanisms need to be optimized in post-disaster restoration and reconstruction. This paper’s “BBB” principle provides the basic idea for post-disaster scenic resilience development, of which risk reduction is the most fundamental principle. However, different types of scenic areas need to further explore the specific measures and sequence of resilience development in combination with their regional characteristics. In the future, the development of resilience development measures for scenic spots in geological disaster-prone areas needs to follow the concept of multi-body participation and propose more innovative guiding measures for resilience development with the perspective of resilience theory combined with the regional resources and environment characteristics [
51].
5.2. Conclusions
The restoration and reconstruction of the disaster area is a long-term project. Although the essential restoration and reconstruction tasks were completed after the Jiuzhaigou earthquake, there are still many restoration and reconstruction processes to complete. The study took the lake landscapes as the research object, analyzed the impact of earthquake disasters and the effect of restoration and reconstruction and put forward a resilience development mechanism of post-disaster scenic spots based on the BBB principle based on the evolutionary resilience perspective. The study used high-resolution remote sensing images to analyze the changing process of the Jianzhu Sea, Sparks Sea, Panda Sea, and Wuhua Sea lake landscapes. By comparing remote sensing images at different periods before and after the disaster, it found that the earthquake impacts the lake landscape. After restoration and reconstruction, the water quality of the damaged lake, surrounding vegetation, and road facilities have been improved in response. However, the restoration status of vegetation and construction land around different lake landscapes varies, and only moderate landscape reconstruction has been carried out. The recovery and reconstruction monitoring can be carried out more macroscopically with the help of high-resolution remote sensing images, pending further combination with field exploration to understand the specific recovery situation. In general, the overall landscape effect still needs to be fully restored. In fact, the monitoring and assessment of lake water quality and vegetation diversity in this study can be further assisted by integrating air-space and space monitoring technologies in the future. This will more realistically reflect the restoration and reconstruction situation, and at the same time allow more targeted exploration according to the resource and environmental characteristics of specific affected areas to propose effective measures suitable for the resilience development of different types of scenic areas. To ensure better post-disaster recovery and reconstruction, and to achieve long-term development in the later period of the scenic spot, the research was based on the three principles of risk reduction, scenic restoration, and efficient implementation advocated by BBB. Combined with the evolutionary resilience theory, the overall planning, structural resilience, disaster prevention and reduction, landscape facilities, social psychology, management mechanisms, policies and regulations, monitoring, and evaluation, could be organized to propose specific measures for the resilience development of scenic spots after the disaster to guide the sustainable development of tourism. Post-disaster restoration and reconstruction is a long-term systematic project.
After the Jiuzhaigou Scenic area completed the three-year essential restoration and reconstruction task, the hidden dangers of geological disasters still exist. Combined with the problems found in the monitoring and evaluation of scenic restoration and reconstruction, the proposed scenic resilience development path plays an important role in promoting the sustainable development of scenic areas. The restoration and reconstruction will also have a particular impact on the ecological environment. The rapid increase in tourists in recent years has led to increased algae and sediments in the lake, the degradation of travertine, and increased threats to biodiversity. It is necessary to research the development of tourism resilience based on the concept of BBB to promote tourism in scenic spots to return to their original levels and ensure sustainable tourism development in scenic spots. As a World Natural Heritage site, the destruction of the ecological environment of the Jiuzhaigou scenic area is equivalent to the destruction of the economic sources of production in the region. After a disaster, the restoration and reconstruction of the scenic area must also consider the comprehensive unity of the social, economic, and ecological benefits. Traditional resilience research focuses on urban planning, engineering, and ecology. The resilience research of post-disaster recovery and reconstruction from disaster risk management has only come into view in recent years. It is imperative to explore the development path of tourism resilience based on BBB by analyzing the problems and experiences in restoring and reconstructing the Jiuzhaigou scenic area.