Wetland is a transition zone between terrestrial and aquatic ecosystems, and is a multifunctional and unique ecosystem on earth. It not only contains rich natural resources, but also has huge ecological benefits. It plays an important role in flood and drought control, water conservation, soil conservation, climate regulation, environmental purification, siltation and land formation, degradation of pollutants, protection of biodiversity and provision of production and living resources for human beings. Therefore, wetlands are known as the "kidney" of the earth, and have a very high ecological service value.
American ecologist Costanza and others divided the global ecosystem service function into 17 items: gas regulation, disturbance regulation, water regulation, water supply, erosion control, sediment retention, soil formation, nutrient cycling, waste treatment, pollination, biological control, shelter, food production, raw materials, genetic resources, recreation and culture, etc., which have become the standard and reference for the evaluation of ecological services. The 17 functions have become the standards and references for conducting ecological service evaluation and are accepted by many scholars. For different ecosystem types, the service functions provided by ecosystems vary greatly in content and quantity. Studies have shown that among all types of ecosystems, wetland ecosystems provide the highest value of services. In this chapter, the ecological service value of wetlands in the Yellow River Delta will be assessed.
I. Ecosystem Service Functions of the Yellow River Delta Wetlands
1. Overview of the Yellow River Delta Wetlands [82]
The Yellow River Delta, located in Shandong Province, bordering on the Bohai Sea and east of the Laizhou Bay, is formed by the Yellow River, which is the river with the largest sand content in the world. It is a silted beach and continent formed by the deposition of a large amount of sediment to the mouth of the sea, and is known as the youngest land in China. The Yellow River Delta is rich in wetland resources, including offshore and coastal wetlands, riverine wetlands, marshes and marshy meadow wetlands, as well as artificial wetlands dominated by rice paddies, reeds and ponds, etc. The Yellow River Delta is the fastest-growing wetland ecosystem in the world, and the most complete and expansive one in China's warm-temperate zone. With an area of about 4,500km2, the wetland is a wetland of international importance required to be registered by the contracting parties to the Ramsar Convention on International Wetlands. It was established as the Yellow River Delta National Nature Reserve as early as 1992, the largest estuarine delta nature reserve in the country, and is one of the most representative examples of estuarine wetland ecosystems worldwide.
2.Service Functions of the Yellow River Delta Wetland Ecosystem [83, 84, 160, 163]
The wetland ecosystem of the Yellow River Delta has the following service functions:
2.1 Abundant Land Resources and Land Formation and Land Creation Functions
2.1.1 Land Resources Functions: The Yellow River Delta is rich in land resources, and the per capita land area of its main city Dongying is 0.47 hm. The per capita land area of Dongying, the main city of the Yellow River Delta, is 0.47hm2, and there is still 3.5×105hm2 of barren and alkaline land to be developed and utilized. According to the evaluation of the suitability of land reserve resources, 8.65×104hm2 of land is suitable for agriculture (arable land), 1.313×105hm2 for forestry and pastoralism, and 1.322×105hm2 for aquaculture and salinity. a large area of wetland has been maintained in its original state. This pollution-free, flat and fertile land is known as the world's most vital "virgin land".
2.1.2 Land formation: The Yellow River Delta is the fastest estuarine delta in the world, with about 20-23km2 of new land formed every year [86].
2.2 Function of marine resources
The coastline of the delta is 350km long, with a beach area of 1.2×105hm2.Because the Yellow River and other rivers bring a lot of nutritive salts and organic matter into the sea, it is the richest water area of the Bohai Sea in terms of zooplankton and flora and fauna, and it provides a good condition for the reproduction and growth of fishery resources such as fishes, shrimps, crabs, and shellfish, and the increase of culture. Known as the "township of a hundred fish" and "Oriental shrimp hometown".
2.3 Habitat Function
There are 1,524 species of wildlife in the area, of which 418 species of marine aquatic animals, belonging to the national key protection of about 170 species, including the porpoise, howling dolphins, spotted seals, minke whales and sperm whales, and other five species; 108 species of freshwater fish, belonging to the national key protection of the Dachshund's Fresh, White Fresh, and Songjiang Seabass, and other three species.
The delta is also known as the "bird paradise", is the inland of Northeast Asia and the Western Pacific Rim an important migration of birds "stopover" and wintering, roosting, breeding places. It has been found that 270 species of birds live here, accounting for about 22.3% of the total number of birds in the country, including 7 species of national-level protected birds: Danding Crane, Whooping Crane, White Crane, Great Duck, Chinese Autumn Duck, White-tailed Sea Eagle and Golden Eagle; and 34 species of national-level protected birds: Whooper Swan, Gray Crane, Mandarin Duck, and White Pillowed Crane. The black-billed gull, a rare bird with a very small stock in the world, also has a large distribution in the nature reserve and makes nests, lays eggs and flourishes here. Included in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), there are 40 species of birds, and from November to March every year, it is a good time for bird-watching. On the mudflats and marshes along the mouth of the Yellow River, various kinds of migratory birds such as cranes, geese, black-billed gulls and wild geese, and other birds, travelers and birds, can easily be formed into groups of thousands of birds, which spread out over the sky, flying up and down, and the birds are competing for the birds' song and singing. People liken the Yellow River Delta to an international airport for birds.
2.4 Functions of material production
The Yellow River Delta can provide rich animal and plant products such as fish, shrimp, crab, shellfish and algae, etc., which are rich in nutritious foodstuffs; there are special wild medicinal plants, mainly alkali ponts, salt horn grass and yellow bearded vegetables, etc.; many animals and plants are also important raw materials for the development of light industry, such as reeds, which is an important raw material for papermaking; the use of wetland animal and plant resources indirectly drives the development of processing industry; agriculture, agriculture, and agriculture are the main industries in the Yellow River Delta, which are the main industries in the Yellow River Delta. The utilization of wetland plant and animal resources indirectly leads to the development of processing industry; agriculture, fishery, animal husbandry and secondary production to a large extent depends on the natural resources provided by the wetland. It also includes a variety of biological resources and marine aquatic products resources. The unique ecological environment of the Yellow River Delta and the unique natural conditions make this wetland unusually rich in vegetation, soil and water organisms, birds and other biological resources. There are 393 kinds of plants in the Yellow River Delta National Nature Reserve, such as: natural reed swamps, alkali ponies, strange willows, blood replenishing grasses, ya onions and some other saline plants, natural grasslands, natural willow forests, natural tree willow shrub forests, artificial acacia forests, natural live forests and so on. Is a national second-class key protection of endangered plants wild soybeans are widely distributed.
2.5 Sightseeing Tourism and Aesthetic Function
The wetland has beautiful natural scenery, which is a good place for tourism, entertainment and so on. The Yellow River Mouth Wetland Ecotourism Demonstration Area has five functional areas, including Marsh Wetland Ecological Area, Sophora Forest Ecological Reception Area, Reed Wetland Bird-watching Area, Beach Wetland Sightseeing Area and New Land Sightseeing Area, etc. It has set up the Window of Wetland, Flying Snow of Reeds, Floating Fragrance of Sophora Forest, Stacking Cui of Willow Forest, 10,000 Mu of Natural Grassland, Huanglong Entering into the Sea, Reed Sea Labyrinth, Sea-watching at Long Embankment, Sunrise on the Sea, Sunset of Changhe and other " Ten scenic spots", as well as the Yellow River has been built and is under construction "ten first" and other beautiful and charming landscape, in addition to creating direct economic benefits, but also has an important cultural value, in beautifying the environment, regulating the climate, and providing residents with open space has an important social benefit.
The aesthetic value of the wetlands: coastal wetlands of alkali pines, sea pines, isopods and Artemisia ferruginea has a high ornamental value, the vast reeds of the blue waves rolling, water countryside, the sky blue, birds competing, full of vitality. With the Danding Crane and black-billed gulls and other wildlife, it provides a good environment for people to travel and recuperate.
2.6 Educational and Scientific Research Value
The ecosystem of the Yellow River Delta wetlands, the diverse flora and fauna, and the endangered species provide objects, materials and experimental bases for educational and scientific research. The wetland retains the information of past and present biological and geographic evolutionary processes, which is of great value in the study of environmental evolution and paleogeography. Ecologists regard this place as an important base for studying the formation, evolution and development of the new land, biologists regard this place as a gene pool for studying biological derivation and the law of succession, bird experts regard this place as a special territory for studying the survival, habitat and migration law of birds in the inland of Northeast Asia and the Western Pacific Rim, and soil and water conservation experts regard this place as a barometer reflecting the effectiveness of the Yellow River governance. At the same time, it is also a national ecological education base for young people.
2.7 Function of purifying environment
The wetland is conducive to purifying the environment and improving its quality. The large area of reeds, meadows and marshes have the function of purifying water quality and degrading various inland river pollutants, thus reducing the pollution of the Bohai Sea, improving the fishery production capacity and ecological function of the Bohai Sea, and is a natural sewage treatment plant. Marsh reeds have obvious effects on various pollutants in water, such as BOD5, SS, nutrient elements N and P, trace elements, difficult to degrade organic matter as well as pathogenic bacteria, etc. Its main mechanism is physical sedimentation, filtration, adsorption, chemical precipitation, decomposition, biological metabolism and so on. According to the experimental study of P.R. Adelaide and others, the nutrient removal capacity has been enhanced with the increase of wetland productivity, and the ideal turf wetland can remove 92% of phosphorus, and the removal rate of nitrogen is also above 40%. The "red tide" that appeared in the offshore waters in the recent period was formed due to the excess nutrients in the water body. Making full use of the purification function of the wetland is conducive to reducing the pollution of offshore waters and preventing the occurrence of eutrophication.
2.8 Flood storage function
The flood storage function of the wetland is due to the ground slope is very small, the water table is high, in the seawater top support, a large amount of river water stagnation in the coastal wetland, so that this place becomes a natural flood storage reservoir before the land water into the sea. If 5m above sea level as the boundary of the wetland, in addition to the developed rice planting area, can be used as a natural flood storage reservoir area of about 1400km2, according to the average depth of flood water 2m calculation, can be stored 2.8 billion m3, coastal wetlands in the lower reaches of the river to regulate the Yellow River plains of the river water level and water balance plays an important role.
2.9 Function of regulating atmospheric components
The ecosystem regulates atmospheric components by exchanging CO2 and O2 with the atmosphere through photosynthesis and respiration, thus playing an important role in the dynamic balance of CO2 and O2 in the atmosphere. Wetlands are also a source of greenhouse gas emissions, including emissions of gases such as CH4 and N2O.
2.10 Moisture regulation function
Moisture regulation is one of the important functions of wetlands. Wetlands have huge infiltration capacity and water storage capacity, and due to the absorption and infiltration of precipitation by wetland plants, precipitation enters into the river with a lag, and the amount of water entering into the river is reduced, which reduces flood runoff and achieves the purpose of cutting down floods.
Two, wetland ecological service function value assessment method
1. Land formation value
Land formation value is assessed by the market value method (Marketvalueapproach). Through the market survey to understand the local land use right transfer price, take its average value of 410,000 yuan / hm2 to estimate, the Yellow River Delta annual natural land creation of 20 ~ 23km2, the research of this paper uses 21,000hm2 to estimate. The formula for calculating the value of land formation (V) is as follows:
V=Local land use right transfer price×Area of land formation per year
V=V1+V2=(Land area+Area of land formation per year)×Local land use right transfer price=2100hm2×410,000 Yuan/hm2=861 million Yuan
2. Material Production Function
The value of the material production function is also assessed using the market value method. The formula is as follows:
Economic Evaluation of Urban Geo-Environmental Risks
Equation (4-1-1) in which V is the value of material products, including both the value of aquatic products and the value of raw material production; Si is the harvestable area of the ith class of substances, Yi is the medium production of the ith class of substances, and Pi is the market price of the ith class of substances. class of substances in the market price.
The market price of the product is referred to the 2005 national price yearbook and the actual local price. In the estimation of the value of raw materials, the harvestable area is calculated as 50% of the total production area.
3. Atmospheric component regulation value
The atmospheric component regulation function is divided into 3 parts: plants fix CO2, release O2 and emit greenhouse gas gas component regulation function value is the sum of plants fix CO2, value and release O2 value minus the value of greenhouse gas emission.
3.1 The value of plant carbon sequestration
Based on the production of organic matter in the wetland ecosystem of the Yellow River estuary, according to the photosynthesis equation, it is estimated that for every 1g of dry matter, it takes 1.62g of CO2 to be formed, and 1.2g of O2 to be released.
The value of carbon sequestration of plants is usually assessed by the carbon tax approach in the international arena. Carbon tax rate to the Swedish government's proposal of 150 U.S. dollars / t (C) (i.e., 1024 yuan / t) as the standard. This value is undoubtedly high for our country, so the study in this paper adopts our Reforestation cost approach (RCA) for calculation. According to the net increase of annual carbon per unit area of plants and silvicultural cost and the total area of wetland plants, the product of the three to calculate the value of wetland plant carbon sequestration yielded our country's silvicultural cost of 260.9 yuan / t [87].
3.2 O2 release and its value
The economic value was estimated by the afforestation cost method and the shadow price method of industrial oxygen production (Market price), respectively, and the average of the two was taken for calculation. According to the amount of O2 released per unit area with O2 silvicultural cost and industrial oxygen price can be deduced from the economic value of oxygen. the silvicultural cost of CO2 is 352.93 yuan / t [87]. The price of industrial oxygen production is 0.4 yuan/kg [88].
3.3 Emission of greenhouse gases
Based on the emission flux of greenhouse gases from wetland and the area of natural wetland, the dispersion value of greenhouse gases, and the product of the three to get the emission value of greenhouse gases. In this example, the dispersion values of CH4 and N2O proposed by Pearce et al. in the economic analysis of climate change in OECD are used to assess the economic value of these two gases, and the dispersion values of these two gases are adopted as 0.86 Yuan/kg and 20 US dollars/kg, respectively.
4. Water Resource Adjustment Value or Functional Value of Floodwater Storage and Retention
The total water adjustment of the wetlands can be obtained according to the following formula can be obtained according to the following formula
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Equation (4-1-2), Si is the area of the ith land use type, and Di is the depth of water storage of the ith land use type. The water regulation value was calculated using the shadow engineering method. By establishing the cost of shadow engineering of reservoirs with a storage capacity of 1t to estimate the value of the culverted water source The total value of the water regulation function is the product of the total water regulation and the cost of the median storage capacity of the two product of the median storage capacity of the reservoir into. This example calculated that each construction of 1m3 storage capacity needs to be invested in the cost of 0.67 yuan (at present, the domestic research in this area more than the use of this data).
Therefore, the functional value of flood water storage, using the market value method of calculation, according to the flood water storage 2.8 billion m3 calculation, it is
Storage of flood water functional value = 2.8 billion m3 × 0.67 yuan / m3 = 1.876 billion yuan
5. Purification of water value
Wetland purification of water value for the wetland to remove nutrients and heavy metals value of the sum of the value. and The production cost method was used to estimate the value of nutrient removal from sewage in the estuarine wetland ecosystem. Apply the expert assessment method to estimate the value of removing heavy metals. The value of removing nutrient salts is calculated according to the following formula:
Et=Ej×Pj=max{Tj/Nj%}×Pj
In the above formula, Et is the value of wetland purification of N, P, yuan/a; Ej is the amount of sewage purified by the wetland, t/a; Pj is the value of the cost of removing unit sewage by the wastewater treatment plant, yuan/a; Tj is the amount of wetland purification of N, P; Nj% is the content of N, P in sewage. for the amount of N, P in the sewage, Tj/Nj% of the maximum value of the wetland to purify the total amount of combined sewage that is Ej.
Currently, the national secondary wastewater treatment plant treatment of sewage costs for 1600 to 3300 yuan / million t (including tons of water investment costs, tons of water running costs, tons of water sludge treatment investment costs, tons of water sludge treatment and running costs, etc.), the monthly take the average value of 2450 yuan / million t [89]. Combined sewage nitrogen content Nn% is 2.90% [90].
According to the expert assessment method, the value of the environmental benefits of removing heavy metals from the wetland is obtained by taking 40% of the total environmental benefit value of removing heavy metals [91].
6. Habitat value
The habitat value was preliminarily valued using the alternative method, and the average of this value and the habitat value of the global wetland ecosystem was taken as the habitat value of the estuarine wetland ecosystem. When calculating the habitat value with the alternative method, the preliminary valuation of the habitat value is based on the bird data in the region, where the investment in habitat protection = investment in protection works + investment in scientific research and culture × 50%.
7. Cultural scientific research value
The average scientific research value per unit area of ecosystem in China of RMB 382/hm2 and the average value of Costanza et al.'s value of global wetland ecosystem's scientific research and cultural function of RMB 861/hm2 of RMB 3129.9/hm2 were used as the scientific research value of estuarine wetland.
8. Aesthetic (Tourism) Value
The tourism value consists of three parts, namely, travel cost expenditure, value of time spent on travel, and other costs, and was calculated using the number of tourists received in 2005.
Travel Expenses = Transportation Expenses + Accommodation + Park Tickets, Attraction Tickets and Service Costs
Value of Travel Time Spent = Total Tourist Travel Time x Tourist Opportunity Wage per Unit of TimeOther Costs = Photography, Shopping Costs
In the calculation of the value of time spent on travel, the tourist's wage is calculated at 90 yuan/d. Tourist opportunity wage costs are generally 30% to 50% of actual wages [92], and a discount rate of 40% was used in this study.
9. Total ecological value of estuarine wetlands
The total value is equal to the sum of each value, i.e.
Total ecological value = land-forming and land-forming value + value of material production + value of regulation of atmospheric components + value of water regulation + value of purification of water bodies + value of habitat + value of cultural and scientific research + value of aesthetics (tourism) + function of storing and retaining flood water
Third, the results of assessment and Discussion
This paper classifies the ecosystem service functions of the Yellow River Delta wetlands into 8 types, and obtains the service value of the wetland ecosystem of 9.45 billion yuan/a. The results of the assessment of each service value are shown in Table 4-1-1, of which the ecological service value of the wetland is higher in the value of terrestrial land formation, the value of material production and the value of cultural and scientific research, followed by the value of cultural and scientific research. scientific research value is higher, followed by aesthetic value, water purification value, habitat value, water regulation value and gas regulation value The service value of the Yellow River Delta wetland per unit area is 17,900,000 yuan/hm2-a, which is much larger than the national ecosystem service value per unit area (0.54 million yuan/hm2-a), and is comparable to the results of the ecological function value assessment of the wetland of Yangtze River estuary by Wu Lingling et al. [177], which is comparable to the results of the ecological function value assessment of the wetland of Yangtze River estuary. The results were comparable. This indicates that the service value of the wetland ecosystem is high, which is consistent with the results of Costanza's study.
Table 4-1-1 Results of the ecosystem service value assessment of the Yellow River Delta
(1) The land formation and land creation value of the Yellow River Delta wetlands is high, accounting for 10.71% of the total value. As the river water in the middle and upper reaches of the Yellow River (especially the annual water and sand transfer project after the operation of Xiaolangdi Reservoir) transports a large amount of river sand into the Yellow River estuary to accumulate into land, creating rich mudflat and land resources, it determines that the wetland has a high value of land formation and land creation.
(2) There are usually two kinds of assessment for the value of habitat, one is the substitution method, which is to substitute the value of habitat according to the direct investment of the protected area; the other is the weighted variable valuation method (CVM-contingent valua-tion method), by investigating the value of the WTP (Willingtopay, Willingness to pay) or the WTA (Will-ingness to accept, Will-ingness to accept, Will-ingness to accept, Will-ingness to accept, WTA). Will-ingness to accept, accept compensation) can be realized.CVM is greatly influenced by the subjective factors of the evaluator, and in developed countries with a low Engel's coefficient, where people pay more attention to the environment, they pay more for the value of the habitat. And the use of the alternative method will be the investment in protected areas to replace the habitat value, is based on the importance of protected areas in our country and the ability to pay, the results are lower than the world level of assessment of habitat value, the authors believe that it must be established on the basis of the appropriate national conditions, but also to take into account the evaluation of foreign countries on this function.
The results of this evaluation show that the habitat value is 20.71% of the total value, which is an extremely high percentage. As the evaluated area is one of the few in the world in terms of biodiversity or a variety of rare plants and animals, etc., it is not high by the standards of developed countries, but perhaps it is a bit high for our country's situation.
(3) In the research of this paper, the cultural scientific research value is high, accounting for 21.81%. In fact, the current cultural scientific research value of the Yellow River Delta wetland is far from being developed and utilized, and the actual utilization value is much lower than this value, which also indicates that the potential for the development and utilization of the cultural scientific research value of this wetland is very great.
(4) Among the eight ecological function values mentioned above, the flood storage and water retention function has the highest value, accounting for 23.33% of the total value. Perhaps, for the evaluation area, due to the salinization of soil in most of the area and the relatively poor quality of the water contained, the evaluation result may be on the high side. However, since there is no more appropriate method than the engineering cost method, the result can only be accepted.
(5) When estimating the value of purifying water, the estimation is mainly for the purifying function that has been realized by the wetland, and the estimation of the value of the potential purifying function of the wetland is still to be further researched.