Identifying the Critical Stakeholders for the Sustainable Development of Architectural Heritage of Tourism: From the Perspective of China

: Architectural heritages, especially heritages of tourism, were destroyed in the process of urban reconstruction of China because of lacking protection from stakeholders. Therefore, there is an urgent need to identify the critical stakeholders to perform the responsibility of protection. The paper, focusing on architectural heritage of tourism, aims to identify the most important stakeholders for making them realize their critical roles in maintaining architectural heritages. Moreover, this paper also aims to evaluate the enthusiasm of stakeholders. As a result, the stakeholders with high importance and enthusiasm would be the critical stakeholders in maintaining architectural heritages. Thirteen stakeholders were selected through comprehensive literature review and the reality of China. A questionnaire survey was conducted with the qualiﬁed respondents in Mainland China. A ﬁve-point Likert scale and other statistical methods were used for achieving the results of evaluation. The ﬁndings demonstrated local government, central government, real estate development enterprise, expert groups, administration of architectural heritage protection, and construction company of architectural heritage are considered as the critical stakeholders for the sustainable development (SD) of architectural heritage of tourism. Finally, some helpful implications were introduced for improving the efﬁciency of participation and cooperation among all stakeholders.


Introduction
Architectural heritage of tourism (AHT), as a significant part of cultural heritage and tourism resources [1,2], includes not only the most important commemorative buildings but also the secondary architectural buildings and their natural and artificial environments located in ancient towns and characteristic villages [3]. It is considered as an important cultural attraction and a testimony of history that can tell the historical changes of this city [4,5]. Therefore, AHTs are of great historical and cultural value [6,7]. Nowadays, the economic value of AHT has also been explored and, thus, it obtained great superiority to development in many cities [8][9][10].
Although the vital functions of AHT are defining the distinctiveness of cities and improving their competitiveness in an increasingly globalized world [11], the increasing economic values of AHT make stakeholders covet its economic benefits rather than the historical and cultural values.

Stakeholder Analysis of Sustainable Architectural Heritage Development
A stakeholder can be defined as a person or organization who has the right and capacity to participate in a certain process [30]. Freeman [31] forwarded the notion of stakeholder to any groups or individuals that can influence or be affected by an organization's process of achieving its goals. Based on the classical definition, the involvement of multiple stakeholders was shown to enhance the value and improve the effectiveness of implementing new innovations [32]. Because of the distribution and contention of benefits of stakeholders, a uniform criterion should be designed for balancing the benefits of them. The stakeholder theory emerged at the right moment and was widely accepted and used [33]. From its inception, the stakeholder theory has shown its apparent importance especially when considering that the goals of each individual or group of stakeholders must be considered in order to understand how to satisfy their values [34]. The characteristic or the advantage of stakeholder theory lies in that it focuses on social morality and social responsibility according to the basic requirements of ethics management [35].
The stakeholder theory, which can be traced back to 1984, was proposed by Freeman. The purpose of this theory is to balance the benefits of all stakeholders which include, not only the substantial shareholders, but also other internal or external stakeholders [36]. Certainly, the benefits of stakeholders match with the responsibilities they performed. Therefore, the stakeholder theory also offed a new way when examining the responsibility of a stakeholder in a certain organization or a mission [37]. Nowadays, the stakeholder theory has been applied in many areas. The components and classifications gained an in-depth discussion by scholars around the world. From the perspective of a company, the stakeholders include shareholders, employees, creditors, suppliers, consumers, competitors, and other stakeholders such as local governments, social organizations, and media [38]. All the stakeholders are categorized into different groups based on a certain classification approach. Hannan and Freeman [39] divided all stakeholders into three types based on the extent of their influence on the enterprise production, including, stakeholders holding stocks in the company, groups having economic contact with the company, and other external stakeholders being concerned with social interests with the company. Post, et al. [40] pointed out that the influence of stakeholders on the performance of a company are different and thus all stakeholders are categorized into two groups-direct stakeholders and indirect stakeholders. The former refers to stakeholders who have direct market transaction relationships with the company, while the latter group has non-market relations with the enterprise. Another widely applied classification method which is based on the relationship with the enterprise and whether the stakeholders have social attributes was proposed by Wheeler and Sillanpaa [41]. As a result, all stakeholders belong to four different groups, namely, major social stakeholders, secondary social stakeholders, major non-social stakeholders, and secondary non-social stakeholders.
As far as the area of architectural heritage is concerned, many efforts have been devoted to the research of stakeholders, although the critical stakeholders for the SD of architectural heritage have not been clearly identified. As architectural heritage is often considered as a tourism resource that can provide economic opportunities for many heritage destinations [30], some scholars analyze the stakeholders of architectural heritage from the perspective of the tourism development. Therefore, the reasonable maintenance and conservation of AHT has a critical influence on the sustainability performance of tourism industry and then affects the economic benefits of tourism department and local government. In this view, shareholders of tourism enterprises, tourism management department, employees, residents, tourists, national and local governments, tourist attractions, hotels, and travel and transportation are all stakeholders of the architectural heritage [42]. From this perspective, visitors and tourists are the most important stakeholders [1] because their choices and attitudes towards built heritage play a decisive role in the SD of architectural heritage. Moreover, tourists' satisfaction of the travel experience, including, not merely the travel expenditure, but also other aspects such as the ecological environment protection, is another critical factor for assessing the sustainability performance of architectural heritage. Therefore, the tourism enterprises have an obligation to design an effective maintenance program for AHT and perform the daily maintenance of architectural heritage for achieving their interest requirements such as rich profit returns, long-term survival and development of enterprises, and harmonious relations with community residents. For the area of architectural heritage, the economic and social activities centered on architectural heritage are significant components of the social development of this area which are bound to influence the life of residents in this area. Therefore, local residents are another important stakeholder in the SD of AHT. Ferretti and Gandino [43] pointed out that the community residents and other stakeholders such as tourists, territorial authorities, and tourism associations should be co-designers of programs of regeneration projects of architectural heritage as well as the whole maintenance plan of the heritage site. In return, it would bring great benefits to community residents such as the enhancement of their income and welfare level, the improvement of their living conditions, the increase of employment opportunities, and the more participation in decision making in the SD of AHT and environment.
Government, including central government and local government, are often mentioned by researchers as an important stakeholder [4]. During the protection of architectural heritage, governments are responsible for formulating the policy, specification, principles, and the overall SD plan and supervising the effective implementation of all the action plans. The aim is to achieve the efficient maintenance of AHT and thus realize the coordinated development of economic, social, and environmental aspects in the area of architectural heritage [44]. In order to ensure the achievement of the goal of SD of AHT developed by local government, some governmental and non-governmental institutions, organizations, or work groups were also established under the authority and supervision of local government. Taking Serbia as an example, two important institutions, namely, the Republic Agency for Spatial Planning and the Republic Institute for the Protection of Cultural Monuments, are in charge of the coordination for protecting architectural heritage and developing the planning scheme of the area of architectural heritage [45]. A work group was established to be responsible for running the maintenance project and effectively implementing the maintenance scheme. In the whole process of the maintenance projects, an advisory group that was composed of experts and scholars took charge of providing intellectual support for the executive departments after communicating with international experts in the research area of architectural heritage [30]. The similar departments in charge of the architectural heritage protection are adopted in Québec of France when maintaining its architectural heritages, especially those included on the World Heritage list [46].
In China, there are also some departments and organizations involved in the SD of architectural heritage. Besides the common stakeholders, such as governments and their departments, tourism enterprises, tourists, and residents, local governments authorized the establishment of a non-profit architectural heritage protection committee for coordinating and organizing all the works of sustainable heritage development. For the non-profit organization, the funds required are a great challenge. Therefore, some flexible financing models were designed for raising the capital of construction. In general, real estate development companies were selected as the investors of the maintenance project of architectural heritage in the construction market of China, and in turn they would gain the managerial authority for an optimum year. The confirmed real estate development company is in charge of determining the qualified construction companies and construction technicians to complete the construction task. Based on the results of a comprehensive literature review and the market situation of architecture heritage in China, 13 stakeholders in architectural heritage maintenance were listed as the candidates for identifying who are the critical ones in the SD of AHT. All 13 stakeholders, together with their roles and interest demands, are summarized in Table 1.

Responsibilities Interests Demands References
Central government Establishing the policies and specifications and supervising the implementation A sustainable development of architectural heritage [47,48] Local government Implementing the policies of architectural heritage protection within its administrative division A sustainable development of architectural heritage within its administrative division [9,25] Tourism management departments Checking the operation of architectural heritage A favorable traveling environment including a maximum investment return [42] Community resident committees Communicating the protection plan to residents and coordinating the relationship between residents and administration of architectural heritage Reducing the adverse impact of architectural heritage protection on the community residents [44] Real Estate development enterprise Investing and organizing the project of architectural heritage protection under the authority of local government and administrations Obtaining economic benefits and enhancing the popularity of company [25] Administration of architectural heritage protection Using, managing, and maintaining the architectural heritage The normal operation and maintenance of architectural heritage [45,46] Local residents Participating in the protection of architectural heritage and understanding the policy in the architectural heritage protection Obtaining an increase of income and an improvement of life quality from the protection of architectural heritage [43] Travel agencies Ensuring the fair use of architectural heritage and the less damage of architectural heritage from tourists Obtaining better tourism resource from the protection of architectural heritage [49,50] Tourism investment company Investing for the architectural heritage protection Obtaining maximum profits and the sustainable development of company [44] Expert group Providing intellectual support for the protection of architectural heritage Obtaining theoretical achievements from the experience of architectural heritage protection [30] Media Reporting and disseminating information about architectural heritage protection An objective report and evaluation of the situation in architectural heritage protection [4,9] Construction company of architectural heritage protection Completing the project of architectural heritage protection according to the requirements of quality and time Gaining construction profit from the project of architectural heritage protection [44] Tourists Providing feedback and suggestion for the architectural heritage protection Obtaining better travel experience from the architectural heritage [1,51] Sustainability 2019, 11, 1671 6 of 20

Research Methodologies
This paper aims to investigate the importance and enthusiasm of the 13 selected stakeholders listed in Table 1 and hereby identify the critical stakeholders in the SD of AHT. In order to achieve the objects, a four-stage research framework was designed.

Primary Selection of Stakeholders
A thorough literature review was firstly conducted to select the primary list of stakeholders. On this basis, content analysis was carried out to extract the responsibilities and interests of all selected stakeholders. Moreover, as this paper took the market of China as the research object, the situation of China in the maintenance of architectural heritage was investigated for assisting the research work in this stage. The results of this stage are shown in Table 1.

Assessing the Importance and Enthusiasm of All Selected Stakeholders
As there is no persuasive theoretical method for determining the importance and enthusiasm of stakeholders, questionnaire survey method was adopted in collecting the statements of respondents on the importance and enthusiasm of these 13 stakeholders in the process of architectural heritage maintenance. The identification and classification of the key stakeholders involved in the SD of architectural heritage are determined based on the results of the questionnaire. The successful application of this method in previous studies that had similar research objects to this research can ensure the effectiveness of the research results. The questionnaire in this paper included three parts-(1) basic information of respondents; (2) statements on the importance of stakeholders in the SD of AHT; and (3) statements on the enthusiasm of stakeholders. Moreover, clear descriptions of the purpose of this investigation were explained to ensure that all respondents could understand this survey and thus prevent a low response rate [52]. The five-point Likert scale was used to assess respondent's attitudes towards the importance (5, very important; 4, important; 3, neutral; 2, not important; and 1, not important at all) of the stakeholders in the SD of architectural heritage and the level of agreement on whether the 13 stakeholders have the enthusiasm to participate in the maintenance of architectural heritage (5, strongly agree; 4, agree; 3, medium; 2, disagree; and, 1, strongly disagree).
In order to ensure the pertinence and validity of the questionnaires, Ciqikou, a famous AHT in Chongqing, was selected as the reference for respondents to state their attitudes. It was founded in Song dynasty and was identified as a national folk ancient town and tourist attraction. The state-of-the-art of Ciqikou can basically reflect the actual situation of ancient towns of China. Therefore, the questionnaires were distributed by email and field investigation to employees who work for local government departments, profit-making and non-profit organizations related to Ciqikou, experts in this area, as well as local residents. As a result, a total number of 375 responses were received, with 18 invalid questionnaires which were missing some important information. Therefore, the remaining 357 respondents were retained for further analysis. All the respondents had different positions, from ordinary employees to senior executives, which ensured the comprehensiveness of the statement on the importance and enthusiasm of architectural heritage stakeholders. Moreover, the distributions of respondents' position and education background are shown in Figure 1; Figure 2, respectively. As can be seen from these two figures, more than half of the respondents (55.2%) had a middle-level management position and 73.1% had an undergraduate education background and higher, which demonstrated that most of the respondents had extensive experience and in-depth understanding of the SD of AHT. In light of respondents' experience, education background, and the scope of the survey, their statements were respective for the study for ensuring the reliability of the research results. respondents' position and education background are shown in Figure 1; Figure 2, respectively. As can be seen from these two figures, more than half of the respondents (55.2%) had a middle-level management position and 73.1% had an undergraduate education background and higher, which demonstrated that most of the respondents had extensive experience and in-depth understanding of the SD of AHT. In light of respondents' experience, education background, and the scope of the survey, their statements were respective for the study for ensuring the reliability of the research results.   respondents' position and education background are shown in Figure 1; Figure 2, respectively. As can be seen from these two figures, more than half of the respondents (55.2%) had a middle-level management position and 73.1% had an undergraduate education background and higher, which demonstrated that most of the respondents had extensive experience and in-depth understanding of the SD of AHT. In light of respondents' experience, education background, and the scope of the survey, their statements were respective for the study for ensuring the reliability of the research results.   Furthermore, the knowledge of all the respondents on the SD of AHT was another crucial factor impacting the reliability of the findings. Therefore, the authors of this paper insist that the statements from respondents who did not have an understanding of architectural heritage cannot ensure the reliability of the investigation. Therefore, all the respondents were selected from the heritage site for enhancing respondents' level of understanding of the architectural heritage. However, as shown in Figure 3, there still were 11.2% (40 respondents) of all the respondents lacking even a basic knowledge of architectural heritage. Therefore, the statements from these 40 respondents were neglected in the following steps of this research. The remaining 317 valid questionnaires provided a good foundation for the objectivity and credibility of the questionnaire results. from respondents who did not have an understanding of architectural heritage cannot ensure the reliability of the investigation. Therefore, all the respondents were selected from the heritage site for enhancing respondents' level of understanding of the architectural heritage. However, as shown in Figure 3, there still were 11.2% (40 respondents) of all the respondents lacking even a basic knowledge of architectural heritage. Therefore, the statements from these 40 respondents were neglected in the following steps of this research. The remaining 317 valid questionnaires provided a good foundation for the objectivity and credibility of the questionnaire results.

Data Process and Validation
Firstly, the reliability test measured by Cronbach's coefficient (α) was conducted to assess the reliability of the Likert scales in the investigation. The Kaiser-Meyer-Olkin (KMO) test was then applied for measuring the validity of the data. The value of 0.7 was accepted as the minimum value that could verify the internal consistency of all the responses according to the standard mentioned by Jiao, et al. [53]. The acceptable values should be greater than 0.5 [54].
Secondly, mean scores were used to determine the level of importance and enthusiasm of all the 13 selected stakeholders in the SD of AHT. The mean score was computed by the following formulas: where n is the total number of respondents; aij is the score of the importance of stakeholder i stated by respondent j; and Xi is the mean score of the importance stakeholder i.
where n is the total number of respondents; bij is the score of the degree of enthusiasm of stakeholder i assessed by respondent j; and Yi is the mean score of the enthusiasm degree of stakeholder i in the SD of AHT.
Finally, the paired samples t-test was adopted to test the significance of the mean scores difference between the selected stakeholders. If the ρ-value is less than 0.01, it means there is statistical significance between the mean scores of the two stakeholders compared to each other at a 99% confidence level. Similarly, a ρ-value less than 0.05 stands for a statistically significant difference at a 95% confidence level [55]. All these two cases are discussed in this research. 11

Data Process and Validation
Firstly, the reliability test measured by Cronbach's coefficient (α) was conducted to assess the reliability of the Likert scales in the investigation. The Kaiser-Meyer-Olkin (KMO) test was then applied for measuring the validity of the data. The value of 0.7 was accepted as the minimum value that could verify the internal consistency of all the responses according to the standard mentioned by Jiao, et al. [53]. The acceptable values should be greater than 0.5 [54].
Secondly, mean scores were used to determine the level of importance and enthusiasm of all the 13 selected stakeholders in the SD of AHT. The mean score was computed by the following formulas: where n is the total number of respondents; a ij is the score of the importance of stakeholder i stated by respondent j; and X i is the mean score of the importance stakeholder i.
where n is the total number of respondents; b ij is the score of the degree of enthusiasm of stakeholder i assessed by respondent j; and Y i is the mean score of the enthusiasm degree of stakeholder i in the SD of AHT. Finally, the paired samples t-test was adopted to test the significance of the mean scores difference between the selected stakeholders. If the p-value is less than 0.01, it means there is statistical significance between the mean scores of the two stakeholders compared to each other at a 99% confidence level. Similarly, a p-value less than 0.05 stands for a statistically significant difference at a 95% confidence level [55]. All these two cases are discussed in this research.

Results, Discussions, and Extraction of Implications from the Results
In this stage, all the 13 stakeholders were categorized into different groups according to the level of their importance and enthusiasm. A matrix was designed to demonstrate the relative position of all the 13 stakeholders. Finally, a comprehensive analysis on the importance and enthusiasm of stakeholders on the SD of AHT and the implications for improving the efficiency of architectural heritage were conducted based on the statistical results. Table 2 shows the results of the reliability and validity test of the investigation. It can be seen that the Cronbach's alpha coefficient was 0.895 for the statement of importance of all selected stakeholders. The Cronbach's alpha coefficient of the degree of enthusiasm of stakeholders was 0.873. Moreover, the KMO values for the statement of importance and enthusiasm of stakeholders were 0.873 and 0.872, respectively. All the test results verified that the five-point scale measurement investigation was reliable and valid for the purpose of this research.  Table 3 represents the survey results on the importance of the 13 stakeholders. The different values of importance mean that the respondents had different recognition on the importance of different stakeholders in the SD of AHT. It can be seen from Table 3 that there were five stakeholders with a mean score more than 4.00. Local government had the maximum mean score (4.37) and ranked first from the perspective of importance, followed by the real estate development company (4.35), central government (4.32), local residents (4.19), and expert groups (4.05). This reflects that these five stakeholders play a leading role in the SD of AHT. On the contrary, the travel agency, the media, and the community resident committee had a mean score value less than 3.00 and thus ranked in the last three positions of the 13 stakeholders. The low scores of the travel agency (1.68) and media (2.40) indicate that the respondents were in agreement on the weak role of the two stakeholders. It could be because the respondents regard travel agencies just as the user of architectural heritage for the economic benefits and they will never proactively devote themselves to the protection of architectural heritage. Moreover, the power of media is not powerful enough for arousing the attention of relative departments in charge of the SD of AHT. Unexpectedly, as a communication intermediary between government and residents, community resident committees got a low score (2.97). This demonstrates that the daily routines of community resident committees in China concentrate on the basic livelihood issues such as mediating neighborhood disputes, keeping the safety of the community, and other convenience services for local residents. They need to continue efforts to enhance the capability of participating in major issues related to social development such as the SD of AHT.

Results and Discussions
Another important value that should be noted in Table 1 is the value of standard deviation of the 13 stakeholders. There are two groups of stakeholders based on the comparison results between the values of standard deviation to 1. The first group includes central government, local government, the real estate development company, the travel agency, expert groups, local residents, and administration of architectural heritage protection, for which value of standard deviation is less than 1. The results indicate that the statements of all respondents on these seven stakeholders are more uniform and concentrated. Therefore, the mean scores of these stakeholders evaluated by the respondents can be directly used as the judgment standard for determining the importance of stakeholders. However, the values of standard deviation of the other six stakeholders are all greater than 1, especially the value of the community resident committee, which is as high as 1.40. Therefore, the statements of respondents on these six stakeholders are very discrete. Therefore, the large difference cognition of respondents demonstrates that further analysis should be conducted for determining the importance of stakeholders. The percentages of five Likert scores from 1 to 5 for each stakeholder were calculated for assisting the further analysis, as shown in Table 4. It can be seen from Table 4, the statements on the tourism management department (mean score = 3.21) obtained from respondents concentrated on points 2 (24%), 3 (34.7%), and 4 (27.4%) with a total percentage of 86.1%. Moreover, the value of standard deviation for this stakeholder was 1.01-only 0.01 higher than 1. This means that the dispersion degree of respondents' statements can be neglected. For the construction company of architectural heritage, although the value of standard deviation was 1.29, more than half of the respondents believed that this stakeholder is important or very important for the SD of AHT because of the total 59% percentage for points 4 and 5. Similar situations occurred in the stakeholders of the tourism investment company, tourists, and the media. Although the values of standard deviation for these three stakeholders were higher than 1, more than half of the respondents gave a close evaluation on their importance. For example, the first two percentages of score for media were 2 and 3 with percentage of 39.7% and 27.4%, respectively. However, it is worth noting that the statements on the importance of community resident committees had the greatest divergence among the respondents, although more than 40% of the respondents considered that community resident committees played a weak role in the SD of AHT. This can be attributed to the busy basic community services and the lack of ability and energy in participating the SD of AHT, although some respondents expected the community resident committee be a critical part of the SD of AHT. It means that the community resident committee should adjust its responsibilities and enhance its ability for adapting to the requirements of affairs related to the social sustainable development.
Based on the analysis above, the following conclusions can be drawn: In the opinion of the respondents, five stakeholders, namely local government, real estate development enterprises, central government, local residents, and expert groups, are the most important stakeholders for the SD of AHT. The importance ranking of all stakeholders is shown in Figure 4. responsibilities and enhance its ability for adapting to the requirements of affairs related to the social sustainable development.
Based on the analysis above, the following conclusions can be drawn: In the opinion of the respondents, five stakeholders, namely local government, real estate development enterprises, central government, local residents, and expert groups, are the most important stakeholders for the SD of AHT. The importance ranking of all stakeholders is shown in Figure 4. Although the importance of these 13 stakeholders was analyzed based on the numerical difference of the mean scores, the significance of difference between each stakeholder were not considered. Therefore, paired-samples t-test method was used for achieving this goal. The t-test results are shown in Table 5. The results are only expressed on the upper part of symmetric matrix because of the same comparative results on the bottom half.  Although the importance of these 13 stakeholders was analyzed based on the numerical difference of the mean scores, the significance of difference between each stakeholder were not considered. Therefore, paired-samples t-test method was used for achieving this goal. The t-test results are shown in Table 5. The results are only expressed on the upper part of symmetric matrix because of the same comparative results on the bottom half.  For each matching test between two stakeholders in Table 5, two kinds of values were calculated. One was expressed in parentheses and another one was not. The values which are not in parentheses refer to the numerical difference of the mean scores of importance between two different stakeholders, while the values in parentheses are the results of the paired-sample t-test between two stakeholders. If the difference between two stakeholders was significant at the 95% or the 99% confidence level, it is marked with * and **, respectively. Moreover, an underline represents the non-significant difference between a pair of stakeholders' importance. Among the 78 pairs of matching tests, four pairs did not pass the paired-sample t-test, which are marked with underlines in Table 5. The four pairs are local government (LG) and central government (CG), real estate development enterprise (REDE) and central government (CG), real estate development enterprise (REDE) and local government (LG), and local residents (LR) and expert group (EG). All the stakeholders involved in the four matching pairs are the first five important stakeholders according to the numerical value of mean scores. The results provided further proof of validity and effectiveness of the statistical data from all respondents. The other 74 pairs, especially those between the last five stakeholders and the first five important stakeholders, were significantly different according to the t-test results. Therefore, the ranking of the 13 stakeholders demonstrated in Figure 4 can be used as the reference for determining the importance of stakeholders in the SD of AHT. Table 6 represents the survey results on the enthusiasm of stakeholders in the SD of AHT. It can be seen that there are different statements on the enthusiasm of stakeholders as the mean scores ranged from 2.12 to 4.49. There are five stakeholders with a mean score more than 4.00, including central government (4.49), local government (4.40), tourism investment company (4.02), expert group (4.31), and administration of architectural heritage protection (4.13), among which central government ranked first from the perspective of enthusiasm on the SD of architectural heritage. This demonstrates that these five stakeholders were generally considered to be highly motivated in the SD of architectural heritage. Similar to the results of the importance investigation, travel agency, the media, and the community resident committee also got a mean score value less than 3.00 for enthusiasm, and thus ranked the last three positions in the 13 stakeholders. The low scores of travel agency (2.12) and media (2.28) indicate that the respondents had an agreement on the poor enthusiasm of the two stakeholders. For the media, the low score on enthusiasm means that there is still much space for more propaganda on the positive and negative events about the maintenance and conservation of architectural heritage for arousing the awareness of the public to do what they can for the improvement of the sustainability performance of architectural heritage. The reasons for the low score of travel agency may be various negative activities imposed on the tourists. All the respondents are tourists in their daily life. As mentioned above, the travel agencies function as the user of architectural heritage for economic benefit maximization. The extreme economic benefit pursuit often leads to the contradiction between travel agencies and tourists. As a result, the negative images are adjudged by all the respondents. Unlike the results of the statement on stakeholders' importance, the real estate development enterprise and local residents are not in the first five groups based on the value of the mean score. For most of the real estate development enterprises in China, their main development programs concentrate on the public buildings and commercial residential housings. Very few real estate development enterprises depend on the maintenance projects of architectural heritage. Therefore, the benefits from architectural heritage maintenance projects have little contribution to enterprise revenue. Comparatively speaking, the travel investment companies who live on investing in tourism projects have more enthusiasm in the SD of AHT. The low enthusiasm of local residents' attributes to their low level of consciousness. However, another critical factor that impels the low enthusiasm is the low participation of local residents in formulating and executing the plans of the SD of AHT. The feeling of being kept out of affairs aggravates the decline of enthusiasm to pay close attention to the SD of AHT.

Enthusiasm of the Stakeholders on the Sustainable Development of Architectural Heritage
Regarding the value of standard deviation of the 13 stakeholders in Table 6, central government, local government, tourism management department, expert group, and administration of architectural heritage protection have a value of standard deviation less than 1. The results show that the statements of all respondents on these five stakeholders are more uniform and concentrated. Therefore, the mean scores of these stakeholders evaluated by the respondents can be directly used as the judgment standard for determining the level of enthusiasm of stakeholders. However, the values of standard deviation of the other eight stakeholders are all greater than 1. Therefore, the statements of respondents on these eight stakeholders are very discrete. Therefore, the large difference cognition of respondents demonstrates that further analysis should be conducted for determining the level of enthusiasm of stakeholders. The percentages of five Likert scores from 1 to 5 for these eight stakeholders were measured, as shown in Table 7. It can be seen from Table 7 that the scores of the construction company of architectural heritage protection (mean score = 3.80) obtained from respondents concentrated on points 3 (21.8%), 4 (33.1%), and 5 (31.2%), with a total percentage of 86.1%. Moreover, the value of standard deviation for this stakeholder was 1.07-only 0.07 higher than 1. This means that the dispersion degree of respondents' statements is in an acceptable range. Similar situations occurred in the stakeholders of travel agency and media. Although the values of standard deviation for these two stakeholders were higher than 1, more than half of the respondents gave a close evaluation on their enthusiasm. For example, the first two percentages of scores for travel agency were points 1 and 2, with percentages of 31.2% and 42.0%, respectively. For real estate development enterprise, although the value of standard deviation was 1.20, more than half of the respondents believed that this stakeholder is active or very active in the SD of AHT because of the total 62.5% percentage for points 4 and 5. In spite of the fact that it was not ranked in the first five group based on the mean score of enthusiasm, the increasing benefits from the maintenance and conservation of architectural heritage are evoking the participating enthusiasm of real estate development enterprises. The local residents and the media have an acceptable consistent degree of statements from the respondents because more than half of respondents assign points 3 or 4 for their enthusiasm. However, the special situation still occurred for the stakeholder of community resident committees, because there are small gaps between the percentages of the five Likert scores on the enthusiasm of community resident committees. Despite this, point 3 accounts for the highest percentage of the five Likert scores, which is consistent with its mean score (2.86).
Based on the analysis above, the mean scores evaluated by all respondents can be used for assessing the level of enthusiasm of all stakeholders. Currently, the five stakeholders, namely central government, local government, expert group, administration of architectural heritage protection, and the travel investment company, are the most active participators. The ranking of the level of enthusiasm of all stakeholders is shown in Figure 5.
the maintenance and conservation of architectural heritage are evoking the participating enthusiasm of real estate development enterprises. The local residents and the media have an acceptable consistent degree of statements from the respondents because more than half of respondents assign points 3 or 4 for their enthusiasm. However, the special situation still occurred for the stakeholder of community resident committees, because there are small gaps between the percentages of the five Likert scores on the enthusiasm of community resident committees. Despite this, point 3 accounts for the highest percentage of the five Likert scores, which is consistent with its mean score (2.86).
Based on the analysis above, the mean scores evaluated by all respondents can be used for assessing the level of enthusiasm of all stakeholders. Currently, the five stakeholders, namely central government, local government, expert group, administration of architectural heritage protection, and the travel investment company, are the most active participators. The ranking of the level of enthusiasm of all stakeholders is shown in Figure 5. The paired-sample t-test method was adopted to verify whether there was significant difference between the enthusiasm level of each stakeholder. The results are shown in Table 8. Table 8. The results of paired-sample t-test between the enthusiasm of each stakeholder.

CG
LG   The paired-sample t-test method was adopted to verify whether there was significant difference between the enthusiasm level of each stakeholder. The results are shown in Table 8.  Among the 78 pairs of matching tests in Table 8, seven pairs did not pass the paired-sample t-test, indicating that there was no significant difference between the paired stakeholders. The seven pairs are local government (LG) and central government (CG), real estate development enterprise (REDE) and construction company of architectural heritage protection (CCAHP), expert group (EG) and local government (LG), tourists (TU) and travel management department (TMD), travel agency (TA) and media (ME), tourists (TU) and local residents (LR), and administration of architectural heritage protection (AAHP) and travel investment company (TIC). All the stakeholders involved in each matching pair are either the top five stakeholders with high enthusiasm or stakeholders with the similar level of enthusiasm according to the numerical value of mean scores. The results provided further proof of validity and effectiveness of the statistical data from all respondents. The other 71 pairs, especially those between the top five stakeholders and the last five stakeholders, were significantly different according to the t-test results. Therefore, the ranking of the 13 stakeholders demonstrated in Figure 5 can be used as the reference for determining the level of enthusiasm of stakeholders in the SD of AHT.

Critical Stakeholders Analysis
As mentioned above, the critical stakeholders in this research refer to the stakeholders who have both importance and enthusiasm. In this paper, the mean score and the standard deviation were adopted to classify all stakeholders into four groups. Taking the importance of all 13 stakeholders as an example, it supposed that the mean score of importance of all 13 stakeholders is X i and the standard deviation is S i . If the value of a stakeholder's importance is more than the sum of X i and S i , the stakeholder would be classified into the first group, which means very important in the SD of AHT. The values which are from X i to the sum of X i and S i belong to the second group. It includes the stakeholders who are important in the SD of AHT. In a similar way, the values ranging from the difference between X i and S i to X i are considered as the third group which includes all the unimportant stakeholders. All the stakeholders with a value less than the difference between X i and S i are regarded as the last group with the most trifling importance. Based on the classification method and the data in Table 3, the results of the classification of the stakeholders' importance are shown in Table 9. Similarly, if the mean score of enthusiasm of all 13 stakeholders and the standard deviation are X e and S e , the classification of stakeholders based on their level of enthusiasm is shown in Table 10. On the basis of considering the classification of stakeholders' importance and enthusiasm, a matrix which includes sixteen boxes was obtained, as shown in Figure 6. The horizontal axis of the matrix demonstrates the level of importance of enthusiasm with an increasing trend from the origin of coordinates. The vertical axis shows the level of importance of stakeholders with an increasing trend from the origin of the coordinates. Each box in this matrix represents the different level of stakeholder's importance and enthusiasm in the SD of AHT. All the 13 stakeholders were grouped into eight kinds of boxes (see Figure 6). For example, if the stakeholder has an importance of category I and an enthusiasm of category II, it will be put into box 2.
On the basis of considering the classification of stakeholders' importance and enthusiasm, a matrix which includes sixteen boxes was obtained, as shown in Figure 6. The horizontal axis of the matrix demonstrates the level of importance of enthusiasm with an increasing trend from the origin of coordinates. The vertical axis shows the level of importance of stakeholders with an increasing trend from the origin of the coordinates. Each box in this matrix represents the different level of stakeholder's importance and enthusiasm in the SD of AHT. All the 13 stakeholders were grouped into eight kinds of boxes (see Figure 6). For example, if the stakeholder has an importance of category I and an enthusiasm of category II, it will be put into box 2. It can be seen from Figure 6 that all the 13 stakeholders are grouped into eight different boxes. For stakeholders involved in boxes 1, 2, 5, and 6, they all have both an important role and enough It can be seen from Figure 6 that all the 13 stakeholders are grouped into eight different boxes. For stakeholders involved in boxes 1, 2, 5, and 6, they all have both an important role and enough enthusiasm to participate in the activities of architectural heritage maintenance and conservation. Therefore, local government, central government, real estate development enterprise, expert group, administration of architectural heritage protection, and construction company of architectural heritage are identified as the critical stakeholders for the SD of AHT. However, the media and travel agency in box 16 are considered as the negligible stakeholders by respondents because of the low level of importance and enthusiasm. Local residents in box 3 are regarded as a very important power for the SD of AHT. However, the enthusiasm was not showing currently. Therefore, it would be a significant force that should be attracted.

Implications
Different stakeholders play different roles in the SD of AHT. Appropriate participation mechanisms and participation modes should be designed based on stakeholders' importance and enthusiasm. The findings of this paper can provide some helpful implications for guiding the cooperation of critical stakeholders for achieving the SD of AHT.

Consolidate the Importance and Participating Enthusiasm of Critical Stakeholders
The six identified critical stakeholders involve government, management organizations, and enterprises. Measures should be taken to keep their importance.
For central government, the following three key issues reflected from the investigation results must be addressed. Firstly, compulsory and punitive measures should be formulated and strengthened for eliminating the disruptive behaviors of some stakeholders because of the pursuit of economic benefits coming from architectural heritages. As a result, all stakeholders' behaviors would be under reasonable norms and regulations and can meet the requirements of the concept of sustainable development. Secondly, the media has a low level of enthusiasm based on the results in Table 6. Central governments should notify the general information of architectural heritage termly through media and hold special conferences and meetings with local officials. In this way, the enthusiasm of media would be motivated steadily. Thirdly, as an extremely important stakeholder (the mean score of importance = 4.35), real estate development enterprises should fully participate in the SD of AHT. However, the level of its enthusiasm is severely inferior to the level of importance. Therefore, more efficient incentive measures should be launched by government for encouraging the participation of these enterprises in the SD of AHT.
For these management organizations, they undertake the mission of implementing the government programs into the practice of architectural heritage maintenance and conservation. Taking the administration of architectural heritage protection as an example, all respondents gave it a very high evaluation on the enthusiasm (4.13). However, the evaluation on the importance from respondents was low (3.77). It is indirectly reflected that the work performance of administration of architectural heritage protection had not been recognized by respondents, although they work full-heartedly in the SD of AHT. Therefore, introspection is needed and measures should be taken for enhancing the efficiency of their participation.
For companies such as real estate development enterprises, they have the enterprise social responsibility for the sustainable development of their industries and regions [56]. They also have an ethical and moral responsibility for the protection and inheritance of historical culture. Therefore, they are supposed to actively participate in the practice of architectural heritage maintenance and conservation. However, real estate development enterprises only had a low evaluation of their enthusiasm, which was not in compliance with their importance. Efforts should be devoted in the following two aspects. Firstly, awareness of architectural heritage maintenance and conservation should be strengthened. Moreover, taking charge of the SD of AHT should be regarded as a significant component of their enterprise social responsibility. Secondly, the behaviors of developing real estate should not damage local natural and cultural environment. The relationship between new buildings and reserved buildings should be handled properly. Furthermore, real estate development enterprises should strive to make new buildings developed harmonious in architectural style, layout, color, etc., so as to inherit and carry forward local traditional features and styles.

Enhance the Participation of the Public
The essence of the concept of sustainable development is people-oriented. In the process of decision-making of sustainable development plan, the efficiency participation of the public must be ensured. Unfortunately, there is a strange phenomenon that local residents had a very high score of importance and a low level of enthusiasm. Local residents keep a listless attitude on the SD of AHT because of the low evaluation of the level of their enthusiasm (see Figure 5). The low level of enthusiasm can be attributed to the lack of knowledge of sustainable development and architectural heritage. Therefore, knowledge about the importance of architectural heritage to the sustainable development of the society and the improvement of their living standards should be infused to local residents. As a result, local residents may realize that the issue of the SD of AHT is closely related to each person. Another factor impacting the enthusiasm of local residents may be the lack of unimpeded channels for participation which can reduce the participation enthusiasm of local residents. Therefore, an effective participation mechanism which provides an expedite participation channel in the issues of the SD of AHT for local residents should be introduced.

Conclusions
This study adopted a questionnaire survey method to examine the importance and the level of enthusiasm of 13 selected stakeholders in the SD of AHT. Based on the results of the value of importance and enthusiasm stated by 317 respondents, the critical stakeholders with high importance and enthusiasm were identified. The findings demonstrated that there are different levels of importance among the 13 stakeholders and the enthusiasm differs sharply because of their different interest demands. The results showed that local government, central government, real estate development enterprise, expert group, administration of architectural heritage protection, and construction company of architectural heritage are considered as the critical stakeholders for the SD of AHT. They should play leading roles in the SD of AHT. Finally, some helpful implications were introduced for improving the efficiency of participation and cooperation among all stakeholders.
Albeit the purpose was achieved, there are some limitations related to this research. Because some respondents have a basic understanding of architectural heritage, their knowledge will, to some extent, affect their statements on the importance and enthusiasm of stakeholders. Moreover, this study focused on the identification of critical stakeholders considering both their importance and enthusiasm. The reasons for the results were explained according to the reality of China. Because of the complexity of stakeholders, in-depth research is still needed to be carried out in the future. Despite these limitations, this paper suggests some useful implications for governments to take measures in ensuring the sustainable development of architectural heritage.