Article Integrating Ecosystem Services and Eco-Security to Assess Sustainable Development in Liuqiu Island Han-Shen Chen 1,2, Wan-Yu Liu 3 and Chi-Ming Hsieh 4,* 1 Department of Health Diet and Industry Management, Chung Shan Medical University, No. 110, Sec. 1, Jianguo N. Rd., Taichung City 40201, Taiwan; [email protected] 2 Department of Medical Management, Chung Shan Medical University, No. 110, Sec. 1, Jianguo N. Rd., Taichung City 40201, Taiwan 3 Department of Forestry, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung City 40227, Taiwan; [email protected] 4 International Bachelor Program of Agribusiness, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung City 40227, Taiwan * Correspondence: [email protected]; Tel.: +886-4-2284-0849 (ext. 622) Academic Editor: Kelly S. Bricker Received: 20 April 2017; Accepted: 2 June 2017; Published: 9 June 2017 Abstract: Developing sustainable island tourism must be thoroughly evaluated in consideration of ecological, economic, and social factors on account of the fragility of island ecosystems. This study evaluated the ecological footprint (EF) and ecological capacity of Liuqiu Island from 2010 to 2015 using the EF model, establishing an indicator to estimate the value of ecosystem service and eco- security. The empirical results include: (1) the overall value of ecosystem service on Liuqiu Island increased from US$3.75 million in 2010 to US$5.11 million in 2015; (2) the total per capita EF considerably increased from 0.5640 gha/person in 2010 to 4.0845 gha/person in 2015; and (3) the ecological footprint index increased from 0.30 in 2010 to 2.28 in 2015. These findings indicate that island tourism recreational zones gradually increased the pressure on its ecosystem, reduced the eco-security level, and severely damaged the environment, thereby threatening the function and structure of the entire ecosystem. The innovations and contributions of this study is integrating ecological footprint and ecosystem services valuation provide insights into sustainability of an island. The theoretical and practical implications identified in this study should contribute to reducing the gap between research and practice. Keywords: ecosystem service value; eco-security; sustainable island tourism; sustainability assessment 1. Introduction With the increased demand for tourism and recreation resources along with changes in travel patterns and the growing awareness of conservation, the rapid development of island tourism has engendered concern among scholars and experts and encouraged research on international investment [1–4]. Scheyvens and Momsen (2008) [5] indicated that island tourism can be regarded as a new opportunity for development in economically vulnerable small-island developing states (SIDS). Liou and Ding (2004) [6] indicated that the overall characteristics of island and inland resources, including the economy of scale, vulnerability, degree of development, and natural disasters, are different than those of mainland areas. Thus, the development of island tourism faces more restrictions and uncertainties and must be treated differently from tourism development in mainland areas. Moreover, Macleod (2004) [7] reported that the fragility of island ecosystems coupled with traffic restrictions, land and economic patterns, and ethnic and cultural conditions necessitate a comprehensive consideration of island tourism development. Sustainability 2017, 9, 1002; doi:10.3390/su9061002 www.mdpi.com/journal/sustainability Sustainability 2017, 9, 1002 2 of 14 Broadly speaking, the preferences of tourists have changed in recent times as greater numbers of travelers have exhibited an increasing inclination toward ecotourism. At the same time, Taiwan has become an increasingly popular destination for tourists from a variety of other countries. In light of these two trends, the numbers of recreational travelers making visits to Taiwan’s national scenic areas have increased substantially. One such destination, Liuqiu Island, is among the the smaller offshore islands located south of the main island of Taiwan. The island is particularly popular among travelers wishing to experience nature via the island’s wildlife tourism opportunities and wetland ecosystems. The island’s intertidal zone provides some of its most popular recreational experiences, such as the opportunity to see green turtles in their native habitat, with these activities being enhanced by the provision of on-site interpretation services that also serve to encourage sustainable tourism (Lo, 2013) [8]. Relatedly, studies have previously been conducted in order to assess how such recreational tourist activities affect the biodiversity of Liuqiu Island (Lo, 2013) [8], as well as how such experiences impact the behavior of tourists in terms of their being environmentally responsible (Lee et al., 2015) [9]. Unfortunately, it is clear that the island’s burgeoning tourist industry brings with it a number of negative environmental impacts that affect the quality of life for locals as well as aspects of the island’s cultural heritage, with such problems including traffic jams, the excessive use of natural resources, and issues stemming directly from the inappropriate actions of tourists themselves. Liuqiu Island provides multiple uses including food provision, biodiversity maintenance, climate and water regulation, and recreational opportunities. When facing these uses, it is critical to understand the environmental conservation issues. Numerous studies have investigated land use in relation to disaster prevention (Lo, 2013) [8] and developed associated management-oriented mitigation plans (Lee et al., 2015) [9]. This study attempts to enhance the understanding of the factors that influence decision-making processes when managing island sustainability. The primary purpose of this study is to develop and test a revised ecological footprint model to estimate the value of ecosystem service and eco-security, from the perspective of the supply and demand of ecosystem services. The remainder of this article is organized. Section 2 provides the literature review of land use change, the value of ecosystem services, and the ecological securities. Section 3 illustrates the methods comprising the study area, estimation approaches and models. Our study integrates ecosystem service value model and the ecological footprint model. Section 4 presents the results and interpretations of data analysis, and discussions of findings. Section 5 focuses on the conclusion, limitations, and suggestions for future research. The present study contributes three key innovations. First, it introduces the use of the equivalence factor as a means of correcting the model by which the value of ecosystem services are calculated. Second, it provides a table listing the value of ecosystem services per unit area within the area investigated by the study. Third, it applies an enhanced model for determining an ecological footprint that includes the ecosystem service function value, with that model utilized to predict and evaluate eco-security in a quantitative manner. The approach of integrating evaluations of both ecological footprints and ecosystem services seems to be particularly innovative and may provide insights regarding the sustainability of various practices on a given island, even as the island itself is altered over time. It is hoped, relatedly, that the gap between research and practical applications in this field can thus be reduced by the theoretical and practical implications of the study. 2. Literature Review This research discusses topics related to the land-use change affected by tourism development; sustainable management and ecosystem conservation; and consideration of biodiversity, climate change, and other critical environmental concerns. Two models, including ecological footprint and ecosystem services valuation model, were used to construct the theoretical framework for this study in the island context. The proposed incorporated model attempts to advance the understanding and knowledge base of how to assess island sustainability. In short, the section of literature reviewed is organized in the following three sections: land use change; the value of ecosystem services; and the Sustainability 2017, 9, 1002 3 of 14 ecological securities. The purpose of reviewing prior literature would identify remaining gaps in the literature. 2.1. Land Use Change Advances in research on changes in the global environment have shifted both temporal- and spatial-scale studies on land-use and cover change (LUCC) from a global to a regional scale; such studies have focused particularly on administrative, vulnerable, and other ecologically sensitive areas [10–15]. The region analyzed in this study, Liuqiu Island, includes both administrative regions (Liuqiu Township) and natural areas (a fragile, environmentally sensitive area). This study analyzed six years of data on land-use variation on Liuqiu Island by evaluating the changes in land use, and other major types of land-use transfer. To promote a sustainable use of land resource, tourism development on island could bring economic, social, and environmental impacts [16], particularly provide environmental and economic benefits for island tourism or emphasize the reduction of their environmental impacts [17]. Previous research on land use and its influence on the environment have explored the effects from only a single perspective; studies investigating the effects of changes in land development