Value Assessment of Ecosystem Service Functions of Xiamen Park Expo Garden

Xiamen Park Expo Garden, full name is Xiamen international expo garden, is located in Jimei Zhongzhou Island, Xinglin Bay Xiamen, the hometown of Mr. Chen Jiageng, the vast Xinglin Bay water area is the background. The planning area covers a total area of 10.82 square kilometers, including 5.55 square kilometers of land area and 5.27 square kilometers of water area. It is composed of 9 islands and 2 peninsulas. Since its construction in 2007, Xiamen Park Expo Garden has greatly promoted the development of tourism, ecological services and real estate in Jimei District of Xiamen City, and also greatly promoted the development of the surrounding economy. Using the method of ecological economics and mathematics analysis, such as carbon tax law, afforestation cost method, market value method, industrial oxygen production method, expense method, shadow engineering method, conditional value method and achievement reference method etc, some ecological services of Xiamen Park Expo Garden are valued, such as fixed carbon dioxide, release oxygen, air purification, water storage, tourism and leisure, education and scientific research, the real estate value. The total value is about 484 million, of which the value of tourism and leisure is the largest, it is 375.9766 million yuan, and occupies the proportion of 77.71%. By analyzing the total value of the marginal effect of main components, some suggestions are proposed for the construction and development of Xiamen Park Expo Garden.


Introduction
The value of ecosystem services is estimated by ecosystem services and natural capital of economic laws. The concept of ecosystem service was first put forward in 1970 [1]. In 1972 and 1974, Wilson [2] and Ehrlieh et al. [3] improved the concept of "ecosystem service" again, and studied the global environmental service function, pointing out that the destruction of biodiversity has a direct negative impact on the ecosystem service function. In 1997, American scholars Costanza et al. published the value of world ecosystem services and natural capital in the journal named Nature [4]. From the perspective of regional scale, they analyzed the value of 17 ecosystem service functions of 16 ecosystems on a global scale, and the research results showed that: Global ecosystem services value $33 trillion, is 1.8 ~ 2 times of global GDP, including wetland in accounts for only 6% of the surface of the earth to provide as much as $5 trillion of the ecological service value. This discovery caused scholars research on wetland ecological service value of boom , also greatly improve the wetland on the ecology position. The value of ecological service function mainly includes four major aspects: adjustment function, cultural function, support function and supply function. Each of the major aspects can be subdivided into several items (as shown in table 1). These services interact and influence each other to jointly form their tourism value and promoting the economic development of the surrounding areas.

Brief Introduction of Xiamen Park Expo Garden
Xiamen Park Expo Garden, full name is Xiamen international expo garden, is located in Jimei District, Xiamen, the hometown of Mr. Chen Jiageng, the "overseas Chinese flag". It is located in Jimei Zhongzhou Island, Xinglin Bay, Jimei District. The vast Xinglin Bay water area is the background. The water area originally belongs to the beach accumulation landform of the Bay, and then the closed reservoir is formed through the artificial construction of sea embankment, which is called Xinglin Bay Reservoir. The total area of Park Expo Garden Scenic Spot is 10.82 square kilometres, of which the land area is 5.55 square kilometres, the water area is 5.27 square kilometres, and the water area is close to half of the total garden area. It is the only water garden in the world. The Park Expo Garden Scenic Area is mainly composed of forests, grasslands and waters. The functional area planning is generally arranged in the form of peninsulas and islands. It consists of five exhibition islands, four ecological landscape islands and two peninsulas ( Figure 1). It mainly includes the main exhibition area of the Expo, the Ecological Wetland Park, the China Education Park, the Navigation Culture Park, the Hot Spring Island and other related supporting facilities. It is a famous lake, wetland and landscape tourism scenic spot. According to the data and literature of Xiamen meteorological observatory [5], the annual average temperature is 21.1°C, the lowest monthly average temperature is 12.3°C, the annual temperature is 16.0°C, the annual rainfall is 1036mm, the climate is south subtropical monsoon climate, the climate is mild, the rainfall is abundant, and the life is comfortable. Since its construction, Xiamen Park Expo Garden has played a great role in promoting the development of tourism and service industry in Jimei district of Xiamen city, and also greatly promoting the development of the surrounding economy. From the perspective of ecological service value, this paper applies the method of ecological economics, mainly analyzes the accounting Xiamen Yuanbo wetland scenic area in the habitat in recent years, fix carbon release oxygen, purify air, dust retention, water storage, nutrient cycling, tourism and leisure, the value of ecological service functions such as education and scientific research, real estate value-added Propose and think the number of visitors' reduction, water environmental pollution problems.
(The floor plan is from the garden management office of Xiamen Boyuan garden).

Study Method
Combining with the characteristics of actual research area and the research object, mainly applicant carbon tax law, afforestation cost method, market value method, industrial oxygen method, cost method, shadow engineering method, travel cost method, conditions value method . The results of reference  method and other research methods, their specific definition see  Chinese description. Because of the wetland ecosystem service  function value estimation methods have advantages and  disadvantages, please see table 2 [8][9]. This article select and use methods according to the concrete situation, accordance with the preferred direct market method, secondary indirect market method. When both are not easy to get the conclusion, choose to simulate the marketing principles again.

Biodiversity Function
Learned from Xiamen Park Yuanbo scenic area management office and Xiamen municipal bureau of parks and forests. According to the statistics of 2009 [11], there are 19 species and 15 families of rare plants in Xiamen Park Expo Garden scenic spot, including species of national first-class rare plants, 11 species of national second-class rare plants, one species of national third-class rare plants and 3 species of rare provincial plants. Trees were selected from 176 species of 48 families and 41,355 plants in public areas. According to the classified statistics of tree species planning and configuration, among the tree species as the keynote species, there are 31,046 trees of 20 species in the whole park, accounting for 75.07%. There are 7 171 tree species, accounting for 17.34% of 32 tree species. There were 122 tree species with 3 138 plants, accounting for 7.59%. In the selection and application of tree species, broadleaf trees are the main species, accounting for 76.47%, 31,626 plants of 139 species of 41 families, 4 149 plants of 7 species of conifers, accounting for 10.03%, and 5 580 plants of 28 species of Palme, accounting for 13.5%. Bamboo plants are also one of the main materials for plant configuration in Xiamen Park Expo Garden, which can be seen almost everywhere in the scenic spot. According to the statistics of Chen Songhe et al. [5] from 2010 to 2011, there are 10 general and 41 species of bamboo in Xiamen Park Expo Garden, and trees and bamboo are important raw materials for paper making industry. And, Xinglin bay in Park Expo Garden has abundant water resources, which provides favourable conditions for fish breeding, mainly ling fish, silver carp, herring, carp, crucian carp, tilapia. Almond-shaped bay reservoir is a large area of lakes, wind power is relatively smaller than the sea, which is the first selection of wintering waterfowl habitat, the shallow water area on the edge of the water body and suitable for wader's animal life, and the surrounding environment is covered by vegetation, and within the garden, garden vegetation coverage provide foraging and habitat condition for birds mainly has the common cormorants, heron, plovers, purple back starlings almond shaped bay waters community species diversity index is 3.66, ranked first in the coastal wetland bird community in Xiamen [12].
In this paper, use the results reference method to calculate the functions of biodiversity. The results reference method is a method to estimate the economic value of similar environmental service functions with the research results of one or more assessment methods, and after modification and adjustment apply it to the regional environment to be evaluated [13,14]. According to Xie Gaodi's et al. opinioned in [15] the biodiversity function of 2212.2 yuan in the ecosystem function assessment of China's terrestrial wetlands as the standard for the calculation of species habitat function value of Park Expo Garden. Then the functional value of species habitat of the garden is:

Fixed Carbon Dioxide, Releasing Oxygen Value
In this paper, carbon tax law, afforestation cost method and industrial oxygen production method are used to calculate the value of fix dioxide and release oxygen in Park Expo Garden greenbelt. The carbon tax code, is a tax system set up by several countries to cut greenhouse gas emissions, is a way to determine the value of the loss of carbon dioxide by charging for its emissions. Afforestation cost method is to obtain the fixed amount and release amount of annual biomass according to the photosynthetic equation, and then convert the economic value of fixed pure C by combining the average cost of carbon sequestration afforestation in China, and obtain the economic value by combining the current price of domestic industrial oxygen [16][17][18]. The Swedish carbon tax rate is usually 150 USD/t (proposed by Wibe in 1990). According to the exchange rate of 17:33 on July 15, 2016, the exchange rate of 1 USD is 6.681 yuan, equivalent to 1002.15 yuan/t; Industrial oxygen generation method is the basic principle of hypothesis of green oxygen is released by consists of an oxygen plant, according to the [16] [18]. China's industrial oxygen generation average costs is 400 yuan/t, afforestation of carbon sequestration in China cost is 260.9 yuan/t, afforestation cost is 325.93 yuan/t, according to this to calculate the average cost of fixed carbon is 631.53 yuan/t, the average cost of making oxygen is 362.97 yuan/t below will use the above data to calculate the value of fix carbon and release oxygen.
According to the scientific calculation of the Japanese forestry department [6], every square kilometre of forest can absorb 1600 t of carbon dioxide and release 1200 t oxygen through photosynthesis every year. According to the information obtained from Xiamen municipal bureau of parks and forests and relevant materials, the total greening area of the garden expo park is about 1.5 square kilometres at present. According to this can be calculated that: The fixed carbon value of the greenbelt in Park Expo Garden is: The oxygen release value of the greenbelt of Park Expo Garden is: Every year, the total value of fixed carbon and oxygen release in Park Expo Garden is 2.169 million yuan.

The Value of Purifying the Air
Park Expo Garden scenic area near Jimei district irrigation mouth industrial zone, there have many factories, will discharge part of the poisonous gas and dust particles, and itself has a lot of harmful gases in the atmosphere, such as O 3 , NO 2 , CO, SO 2 , PM10, of which the content of sulfur dioxide (SO 2 )), the largest of biological harm is great, green plants can absorb the harmful gas in the air, and purify the pollution of air. According to the study, in the area with 30% green coverage, the carcinogenic substances in the air can be reduced by 58% and sulfur dioxide reduced by more than 90%. The air purification value of green space is mainly reflected in the degradation and purification value of air pollutants (mainly sulfur dioxide) and the benefit of sterilization and dust retention. Recovery fee is adopted here. Recovery fee method is used to estimate the cost of restoring the environment to its original state after it is destroyed. It can evaluate the value of urban green space absorbing toxic gas or dust retention and dust removal. Firstly, it is necessary to determine the cost of controlling toxic gas or dust. Secondly, determine the cost of controlling the toxic gas or dust per unit weight during the evaluation period. Finally, multiply these two together to get the total cost of cleaning up the toxic gas or dust absorbed by the green space.
(I) Purify the value of sulfur dioxide According to the survey and statistics of the garden and expo park, trees are mainly selected for greening in public areas. In terms of tree species selection, broad-leaved trees account for 76.47%, coniferous trees account for 10.03% and palm family accounts for 13.5% [11]. According to China's biodiversity research report [19] From (I) (II), the annual air purification value of Park Expo Garden green belt is 568,500 yuan.

The Value of Water Supply and Storage
This function mainly includes the water storage value of Park Expo Garden and the water conservation value of the green area.
(I) Water storage value Park Expo Garden waters almond shaped bay area original belongs to is the gulf beaches accumulation landforms, 1956 by the artificial building apricot seawall became closed reservoir, the existing water area is about 5.27 square kilometres, learn from the results of the investigation and exploration [11], Park Expo Garden waters not much affected by the causeway bay outside the water of the sea, bay is still as fresh water, water isolation DiNa salinity in 0. 6 ‰ ~ 0. 8 ‰, change is small, and the farther deep the salinity is smaller, more suitable for the growth of plants. The normal water capacity is usually 6.43 million. After renovation and protection. It can be used as an emergency water supply for industry, agriculture and living water in Jimei district and Haicang district in case of special circumstances. According to the information obtained from Xiamen water supply and Xiamen municipal development and reform commission (Xiamen municipal development and reform commission price [2015] no. 1021), the tap water price in Xiamen is divided into three grades. The average price of tap water in the first and second grades is 2.75 Yuan/ton, as the water density is 1000kg/ ton. The total annual water supply value of the Park Expo Garden water area is: (II) The value of conserving water The value of green space water conservation is mainly reflected in the increase of effective water quantity, improvement of water quality and regulation of runoff, which is positively correlated with green space volume. The larger the volume is, the stronger the capacity is. When the volume of the wetland is determined, the larger the precipitation and rain-bearing area is, the stronger the capacity of green land to conserve water is. First according to the water balance method (the basic principle of balance is the law of conservation of mass. The quantity of the water cycle represents the continuity of the water movement (including the phase transition) in the time domain space at any given scale, maintaining the balance of payments in quantity. Calculate the total amount of green water conservation, that is, the difference between green precipitation and evapotranspiration and other consumption. Here, we ignore other consumption and then use shadow engineering (that is looking for alternative markets for goods), Calculate the total amount of green belt water conservation, that is, the difference between green belt precipitation and evapotranspiration and other consumption. Here, we ignore other consumption, and then use the shadow engineering method (i.e., looking for alternative markets for goods, using the same product price on the market to estimate the value of the goods, using the artificial reservoir with storage function as the alternative project) to figure out the value of water conservation. The following formula is: The value of water conservation in the greenbelt forest area of Park Expo Garden = ( ) S P E C × − × S, P and E respectively represent the green area (square kilometres), average annual precipitation (mm) and evapotranspiration (mm) of Park Expo Garden. C is the cost per unit storage capacity, which is 7 yuan. Combined with relevant literature [21,25,26], the average annual evapotranspiration of the national forest is usually 56% of the annual precipitation of the green forest land. Assume that the annual evapotranspiration of the green land in Park Expo Garden is 60%. According to information obtained from Xiamen meteorological bureau and Xiamen forestry bureau, the average annual rainfall in Park Expo Garden area is 1036mm, and the total greening area of Park Expo Garden scenic area is about 1.5 square kilometres, it can be obtained from the above data: Annual water conservation value of green area forest in Park Expo Garden is: 6 3 1.5 10 1036 40% 10 7 0.4351 − × × × × × ≈ million yuan (7) The water supply and storage value of Park Expo Garden is 18.1176 million yuan.

Nutrient Cycling Value
Calculated according to the Ouyang Zhiyun [24] China indirect value of ecosystem nutrient cycling, calculated the ecological system 1 g per fixed carbon, can accumulate nitrogen 0.025 426 g, 0.00201 g phosphorus and potassium. Take November 2015 Hengshui Hebei province NPK fertilizer to an average price of 2019 yuan/ton as a reference, by 3.3, to estimate the Park Expo Garden for nutrient cycling ecosystem service value is: 1600 (0.025426+0.00201+0.01012) 3 1.5 2019 0.0607 × ÷ × × ≈ million yuan (8)

Tourism and Leisure Value
Xiamen Park Expo Garden scenery is beautiful, water close to the island, Wetland Park, Hot Spring Island and regularly holds flower expo, garden expo, lantern fair attracting many tourists from other parts of the country. The cost expenditure method is usually adopted to estimate the value of leisure tourism, and the specific algorithm is [28], leisure tourism value = travel cost expenditure + travel time value + consumer surplus. The travel expenses mainly include the direct and return transportation expenses from the origin to the scenic spots, accommodation and food expenses during the journey, scenic spot tickets and various service fees. The value of travel time is obtained by multiplying the total time tourists spend in scenic spots by the opportunity wage cost per unit of time. The consumer surplus is generally about 10% of other expenses. The opportunity cost is generally 1/3 of the wage cost. The average hourly wage in Xiamen in 2015 is 17

Educational Research Value
Park Expo Garden scenic area of Chinese education park is the first in China with education as the theme of the landscape garden, the garden design style is unique, has the strong sense of history and appeal. To the comprehensive, focused, classical Chinese teaching blind cultural history and the present, expression of "inheriting Chinese nation long culture, promote the healthy growth of Chinese harmonious education", the theme of the attracted the lovers of primary and middle school students and the lovers of education research. Result reference method has been used here to calculate the educational and scientific research value of the Park Expo Garden. Using China's per unit area ecosystem and the average value of 382 dollars a year in [13] and [4]  Yuan/square meters, refresh the record of the Xiamen nonlocal piece of floor price, fully embodies Park Expo Garden's influence on the surrounding real estate. Later, there were "Zhonghangcheng", "oak bay", "IOI Yuanbo bay" and "longhu-Chun Jiang li cheng" on the west were developed. Eastside "crystal lake county" "waterfront one mile", "waterfront community" and the north "palm city", "lotus" series and other real estate were developed, And commercial housing prices grow with time, and Park Expo Garden built and improved. investigation and analysis shows that under the influence of without considering other factors, and the influence of Yuanbo on the surrounding land price has a two dimensional normal distribution characteristics, that is with the increase of Park Expo Garden centre distance, real estate appreciation will decline, but change range decrease with the distance increase, then flattened. Literature [6] divides the plots near Park Expo Garden into three levels according to the distance between the building and the centre of Park Expo Garden (see figure 2). And calculate three levels block 's house price from 2012 to 2014 as well as the average price of house, level classification method has been reffered, combining with the Xiamen city real estate network, Xiamen to guest information, as well as the results of actual investigation, telephone consultation, supplemented by some special unknown housing price and the situation of the three levels of 2015 block buildings and average price. In the third level median home price as a benchmark, calculated the Park Expo Garden in real estate appreciation value. The supplemented real estate situation around Xiamen Park Expo Garden in the past four years is as follows: According to [26], from the time scale of regression model analysis infer the green park, the biggest impact on the surrounding real estate range is 2. 6 km, and from the space dimension of the regression model analysis infer green park affect prices around the maximum range for 1. 59 km. The authors take an average of them is 2.1 km, because of the Park Expo Garden around the center, 1.5 km radius area is water area, distance is too close to the water's edge is not suitable for residential building. It is considered that Park Expo Garden scenic area's maximum radiation radius is 2.1 km + 1.5 km = 3.6 km. The range mainly includes the first level and second level area in figure 2, in fact, the results of our research conform to this conclusion, Park Expo Garden scenic area for the third level of regional value is very weak. There is little difference between the real estate price of the third level plot and that of Jimei plots far away from the Park Expo Garden. Therefore, we in the third level land prices as a benchmark, calculate the Park Expo Garden scenic area the added value of impact on the prices. Note Among them , a b is a year on average for the first level and second level land on the development of the housing area, Among them for a year on average for the first level and second level land on the development of the housing area, they depend on the floor height and degree of the development of the plot. Authors replace the abutment letters, from (11) it can be seen that marginal effect of price appreciation, the first level plot every increase 1 square meters, can increase the value of 5570.25 yuan, while the second level increase is only 1413.75 yuan, while the real estate price changes also affected by recent years the Xiamen city real estate natural increase and other factors (such as the price of the second and third level by the almond shaped bay municipal service center construction of the impact of price increases a lot), However, it can also be clearly seen that the driving effect of Park Expo Garden scenic spot on the surrounding real estate, If

Total Value and Analysis of Ecosystem Service of Xiamen Park Expo Garden
Through the analysis of the third part, Xiamen Park Expo Garden of ecological service function value is about 484 million yuan, accounting for Xiamen, 0.13% of GDP in 2015 (356.5 billion yuan), accounted for 0.97% of GDP (49.4 billion) in 2015 in Jimei district, of which the tourism and leisure value, about 376 million, accounts for nearly 80% of the total ecosystem service value, followed by the real estate appreciation value, accounted for 17.36% of the total value. Other specific proportion information is shown in table 4. For information and accounting process into the problems found in the table, we found that the ecological service value of Park Expo Garden is influenced by four aspects, that is green areas, biological diversity, tourism and leisure, property value added 4 aspects, if the number of ecosystem service value for garden is Y (ten thousand yuan), green space area, biological diversity, the number of tourism and leisure per year, real estate appreciation number respectively because of carbon-oxygen release, purify air, water conservation, nutrient cycling function directly influenced by green areas, water storage value and the sum of the education scientific research value 18.9103 million yuan can be temporary as a constant, with reference to the third part of the discussion is x is mainly related to the propaganda, local transportation and leisure facilities in the park. By comparing the average annual number and scope of 1.4331 million in the paper, it can be seen that the tourism and leisure value of Park Expo Garden has great potential to be developed. What needs to be paid attention to is that the number of tourists living in Park Expo Garden has been decreasing year by year in the past five years, which needs special attention. The real estate appreciation 4 x depends on the greening and leisure facilities of the park. However, due to the limited land, it will gradually approach a stable value, so the real estate appreciation value of Park Expo Garden makes a small contribution to maintaining the sustainable development of the ecology. Reason to upgrade the ecological service value of Park Expo Garden, should be mainly from the 1 x and 3 x the affected and aspects, from (13), Y, respectively, and the partial derivative 1 x and 3 x , can have both the marginal value were 583.77 and 262.65 + (a), the study found that green area, small range, and is limited by public facilities construction to the contradiction of land (both and 5.55 square kilometres, need reasonable balance), the number of tourists growth potential, and with greater weight ascending garden, garden of ecological service value (especially the number of tourists). Therefore, we put forward the following three Suggestions: (1) Increase the proportion of the green area is conducive to improving the ecological service value of Park Expo Garden. Every one square kilometre increase can gain an additional 5.83777 million Yuan of ecological service value. At the same time, the greening rate can increase the tourist comfort level and improve the leisure and health index of people around. In the tourists and people around the publicity, increase the attraction; (2) Increase the propaganda dynamics, in the north station of the underground passage, increase billboards around the wall and optimize the garden, garden surrounding traffic construction, for example, increase from Xiamen north station bus for Park Expo Garden, increase from Xiamen university institute of technology, Xiamen engineering area buses for Park Expo Garden, provide convenience for tourists. (3) Strengthen the construction of supporting facilities of Park Expo Garden, increase the attraction, such as optimizing the construction of Xinglin bay water area, do well in water entertainment activities, often engage in activities in the park, attract shops (such as famous products discount) to live around or inside Park Expo Garden, increase the fun of public tourism and leisure.

Conclusions and Prospects
(1) Based on the research of the Park Expo Garden ecological service system we can found that the top three of the ecological service value respectively is tourism and leisure, real estate appreciation value, water supply reservoir, especially the tourism and leisure value more than 70%, in accordance with the Park Expo Garden construction goal "to build a collection of garden show, leisure, culture, entertainment and education as one of the theme park" basic agreement; Besides reflecting the service value of Park Expo Garden, the ratio of real estate appreciation also reflects the "soaring" speed of housing price in Xiamen in recent years. The water supply and storage value are mainly reflected in the strong water storage and water supply capacity of Xinglinwan reservoir in Park Expo Garden. (2) Ecosystem services evaluation is a multi-disciplinary comprehensive research field, closely with the local natural geographic, economic and social situation picture frames, the current evaluation system is not perfect enough. For Park Expo Garden built time is short, greening area and the Non-greening area supporting facilities is not very perfect, the construction of each island is in constant innovation and update, the reason of our ecosystem service value accounting has a certain reference value, but not accurate enough, need to further optimize the evaluation index, detailed evaluation criteria. How to optimize the construction of land resources, achieve a relative balance between the value of ecological services and profits, and promote the natural, harmonious and sustainable development of Xiamen Park Expo Garden and its surrounding areas are still needed to be considered.