June, 2011
Journal of Resources and Ecology
J. Resour. Ecol. 2011 2(2) 132-140
Vol.2 No.2
Article
DOI:10.3969/j.issn.1674-764x.2011.02.005 www.jorae.cn
Ecosystem Regulating Services and Their Valuation of Hainan Island, China OUYANG Zhiyun*, JIN Yu, ZHAO Tongqian and ZHENG Hua State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, CAS, Beijing 100085, China
Abstract: Ecosystem services were defined as the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life. They include provisioning, regulating, cultural, and supporting services. These form the basis on which regional environmental reserves and development are assessed and for the valuation of ecosystem services. In this paper Hainan Island is used as an example to explore methods of regulating services based on the structure and processes of a natural ecosystem. Ecosystems were classified into 13 types: valley rain forest, mountainous rain forest, tropical monsoon forest, mountainous coppice forest, mountainous evergreen forest, tropical coniferous forest, shrubs, plantation, timber forest, windbreak forest, mangrove, savanna, and crop land. Regulating services and their economic values for Hainan Island ecosystems were assessed and evaluated in terms of water-holding, soil conservancy, nutrient cycle, C fixation and windbreak functions. The economic value of the regulating services in 2002 were estimated at 2035.88×108 to 2153.39×108 Chinese Yuan (CNY), which was eight times the value of provisioning services (wood and agricultural products), estimated at just 254.06×108 CNY. Our analyses imply that ecosystem regulating services play a very important role in the sustainable development of Hainan Island’s society and economy. Key words: ecosystem services; ecological regulating services; Hainan Island
1 Introduction Ecosystem services were defined as the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life. (Daily 1997; Ouyang et al. 1999). They included provisioning, regulating, cultural, and supporting services (Millennium Ecosystem Assessment Board 2003). These form the basis on which regional environmental reserves and development are assessed and for the valuation of ecosystem services. Ecosystem services are also an important research topic in regional ecological assessments and ecological planning (Daily 1997; Ehrlich and Ehrlich 1992; Pimentel 1998). Many case studies and much theoretical discussion concerning assessments of ecosystem evaluations have occurred (Björklund et al. 1999; Gren et al. 1995; Kramer and Munasinghe 1994; Munasinghe 1994; Pearce and Moran 1994). Of specific note is the work of Daily (1997) and Constanza et al. (1997) in the fields of international ecology, economy and sociology. In China, research on ecological services and assessments of Received: 2010-11-06 Accepted: 2011-04-01 Foundation: National Natural Science Foundation of China No. 40635029. * Corresponding Author: OUYANG Zhiyun. Email:
[email protected].
their value originated from investigations in the 1980s into the value of forest resources. Hou et al. (1995) evaluated the economic worth of forests in China in respect to waterholding, as windbreaks, soil conservation and atmosphere decontamination. They showed that the combined value of these three services was 13 times larger than that of timber for the first time. Ouyang et al. (1999, 1996) systematically illustrated the concept, meanings and assessment methods of ecological services and preliminarily estimated the value of ecological services for terrestrial ecosystems in China. Zhou et al. (1999) calculated the approximate public value of ecological services for forest resources in the province of Heilongjiang, and in China as a whole, by applying ecological observation data. Guo et al. (2001) systematically assessed the ecosystem services of terrestrial ecosystems in Xingshan County, Shennongjia. Xue et al. (1997, 1999) assessed indirect ecosystem services of the forest ecosystem in the Changbai Mountain region, and made use of contingent valuation methods to produce a survey about the willingness to pay for the existing value of biodiversity in this area. Li (1999) published “Ecological
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OUYANG Zhiyun, et al.: Ecosystem Regulating Services and Their Valuation of Hainan Island, China
Axiology”, which utilized the example of forest ecosystems to comprehensively summarize the theories and methodology of forest ecosystem services valuation and propose a social development period index to correctly evaluate the results of ecological values. Other research has directly applied the methods of Constanza et al. (1997) to assess the total ecosystem services value of primary forests and grasslands (Chen and Zhang 2000; Jiang and Zhou 1999; Xie et al. 2001). However, established methods for understanding regional ecosystem services, indexing systems and evaluations are lacking. During an assessment process, the impact of ecosystem structure, ecological processes and ecosystem services are usually ignored. Chinese researchers have paid much attention to overseas methods, while less effort has focused on tailoring them to the social-economic characteristics of China. As a result, comprehensive research on the value of regional ecosystem services has been difficult to undertake and apply. Using Hainan Island as an example this study focuses on ecosystem regulating services. From analysis of ecosystem structure, processes and services, methods for evaluating materials and values of ecosystem services are investigated. This was conducted to determine ecosystem services evaluation processes and methods on a regional scale based on the ecology. We are hopeful that through spatial analysis and an assessment of Hainan’s ecosystem services, a scientific base could be established for reasonable land use, sustainable resource utilization and the protection of natural resources.
2 Methods for the evaluation of Hainan Island ecosystem services 2.1 Ecosystem types on Hainan Island According to existing ecosystem structures and ecological
processes, ecosystems on Hainan Island were classified into 13 types. This study assessed ecosystem products and ecological regulating services provided by the Hainan Island ecosystem. The content of the ecosystem product evaluations included income from the agriculture and timber industries on Hainan Island, while the ecological regulating services evaluation included soil conservation, water-holding, CO2 fixation, nutrient cycle and windbreak function (Table 1). 2.2 Evaluation of ecosystem product values The ecosystem product value of Hainan Island is the product or service value provided by the Hainan Island ecosystem for supporting human life. It includes agricultural products and forestry timber values. • Agricultural product value: The term agriculture here refers to macro-agriculture and includes cropping, forestry, animal husbandry and fisheries. Specifically, cropping activities include the cultivation of grains, cotton, oil plants, sugar plants, hemp, tobacco, medicinal materials, melons and other crops, together with the management of tea and mulberry gardens and orchards. Forestry includes timber planting, harvesting of forest products, and the timber used by villagers. Animal husbandry includes all animal breeding and grazing. Fisheries include fish farming and the harvesting of aquatic species and algae. The net value of agricultural production in 2002 was used as a standard for the agricultural service value delivered by Hainan Island ecosystems. • Forestry timber value: Live stumpage value was used in this study as the standard for the forestry timber value. Using the second classification survey data of forestry resources on Hainan Island, annual net growth of the total quantity of timber for each age group in the
Table 1 Index system for assessment of the ecological regulating services of the Hainan Island ecosystem. Soil conservancy Ecosystem type
Surface soil
Silt decreasing
Fertilizer holding
Nutrient cycle Water-holding
Valley rain forest + + + + Mountainous rain forest + + + + Tropical monsoon forest + + + + Mountainous coppice forest + + + + Mountainous evergreen forest + + + + Tropical coniferous forest + + + + Shrubs + + + + Plantation + + + + Timber forest + + + + Windbreak forest + + + + Mangrove Savanna + + + + Crop land + + + + Note: “+” represents the indicators were assessed.
C fixation
N
P2O5 K
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+
+
+
+
Windbreak
function
+
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Hainan forest ecosystem was ascertained by statistical methods. These values were then multiplied by the live stumpage price to give the timber value for each timber stand in the Hainan forestry ecosystem. 2.3 Assessment of the ecosystem’s soil conservation service The ecosystems play an important role in soil conservation in Hainan Island due to heavy precipitation. The quantity of conserved soil material was calculated and then valued by the shadow price method, the opportunity cost method (OCM), and shadow engineering. 2.3.1 Method for assessing the ecosystem’s soil conservation quantity Soil conservation quantity was assessed as the difference between potential soil erosion and actual soil erosion (Equation 1) (Ouyang and Wang 1996; Ouyang et al. 1999). Actual soil erosion refersto soil erosion under the current land cover, while potential soil erosion is the quantity of soil erosion that would occur with no land cover or land management. Ac= Ap–Ar
(1)
AP= R·K·LS
(2)
Ar= R·K·LS·C·P
(3) -1
-1
Ac, soil conservation quantity (t ha y ), AP, potential soil conservation quantity (t ha -1 y -1); Ar, actual soil erosion (t ha-1 y-1), R, rainfall erosivity index; K, factor of soil erodibility; LS, length and slope factor; C, land cover factor; P, mean soil conservation factor. 2.3.2 Method for assessing the economic benefits of soil conservation Using the shadow price method, OCM, and shadow engineering, the economic benefits of soil fertilizer conservation and decreasing abandoned land and silting could be assessed. • Assessment of the fertilizer conservancy value: Soil erosion causes a large amount of soil nutrients to be lost, especially nitrogen (N), phosphorus (P) and potassium (K). Concentrations of N, P and K in the different ecosystems were estimated from GIS averages. The economic benefits of conserving soil
Surface soil conservancy
Soil conservancy
Fertilizer conservancy Silt decreasing Material quantity assessment
Fig. 1 Model of soil conservancy service assessment.
OCM
Shadow price Shadow engineering
fertilizer in the different ecosystems of Hainan Island were determined using the following equation:
Ef=
Ac·Ci·Pi/10 000 (i=N, P, K)
(4)
Ef, economic benefits of protecting soil fertilizer (CNY y -1); A c, soil conservation quantity (t y -1); C i, pure concentration of N, P and K in the soil; Pi, average price of chemical fertilizer. • Assessment of decreasing abandoned lands: The amount of land abandoned due to soil erosion was calculated using the soil conservation quantity and average surface soil thickness (0.6m) (Group of Tropical Agriculture Inquiry in Hainan Island 1981). Then through OCM the annual economic value lost as a result of abandoned land was determined (Equation 5). Es=Ac·B/(0.6·1000·ρ) (5) Es, decreased annual economic value caused by abandoned lands; Ac, soil conservation quantity (t y-1); B, annual income of forestry industry; ρ, soil bulk density (t m-3). • The value of decreasing silting: The movement of silt in China’s main drainage areas has caused 24% of silt coming from soil erosion to enter reservoirs, rivers and lakes (Ouyang and Wang 1996). In this study, the cost of reservoir construction was used to calculate the economic benefits to ecosystems from decreasing silting. En=24%·Ac·C/ρ (6) En, economic benefits from decreasing silt (CNY y-1); Ac, soil conservation quantity (t y-1); C, cost to construct reservoirs (CNY m-3); ρ, soil bulk density (t m-3). 2.4 Assessment of ecosystem water-holding services The water-holding capability of the litter layer and soil were used in this study to quantitatively evaluate the water-holding service of ecosystems on Hainan Island from the perspective of material quantity. Based on the quantity of retained water, the value of ecosystem waterholding services was quantitatively assessed by the shadow
Value of surface soil conservancy
Value of fertilizer conservancy Value of silt decreasing Valuation
Value of soil conservancy
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engineering method. • Assessment of litter layer water-holding capability: The water-holding capability of the litter layer was evaluated based on its current quantity.
M=–0.4723+0.3313W
net growth of each stand in each age group could then be calculated. Using the relative correlativity among trunks, biomass and other tree organs (Equation 8, Table 2) the annual net growth of the quantity of Hainan’s forest stands in each age group were determined.
(7)
M: water-holding quantity of litter, W: current quantity of litter • Assessment of soil water-holding capability: The difference between the maximum soil water-holding quantity and the wilting coefficient constituted the soil water-holding capability. The following model estimated the soil water-holding capability. The percentages of sand, silt, clay and organic matter, the soil bulk density and the total thickness were determined by soil survey.
θ v = a+(b·Vsa)+(c·Vsi)+(d·Vcl) +(e·Vor)+(f ·ρ b) (8) θv , soil water volumetric percentage; Vsa, soil sand percentage; V si, soil silt percentage; V cl, soil clay percentage; Vor, soil organic matter percentage; ρ b, soil bulk density. • Evaluation of the ecosystem’s water-holding service: A value for the ecosystem’s water-holding service was determined by combining two of the resources noted above. Specifically, by overlaying maps of the ecosystem and soil types of Hainan Island with GIS.
2.5 Assessment of the ecosystem’s CO2 fixation service During the evaluation process, the net primary production of all ecosystem types on Hainan Island were calculated based on statistical data and the fourth survey of forestry resources. According to the photosynthesis equation, ecosystems will fix 1.63g CO2 during 1.00 g dry matter production (Editorial Committee of State Report on Biodiversity of China Committee 1997). Based on this fact, the quantity of CO 2 fixation and its value were estimated. The methods for calculating the net primary productivity of all ecosystem types were as follows: • Net production of forests: Forests included valley rain, mountainous rain, tropical monsoon, tropical coniferous, mountainous evergreen broadleaf, mountainous coppice, windbreak, timber, and tropical economic forests and shrubs, but not mangroves. Based on the data from the fourth survey of forestry resources on Hainan Island, the cumulative quantity and the growth rates of each stand in each age group were determined by statistical methods. The annual
BM(t) = SUM(ai· AMi + bi)
(9)
BM, biomass; AMi, cumulative quantity of forest type i. • Annual quantity of the net growth of mangroves: Using the fourth survey of forestry resources on Hainan Island, the area and the cumulative quantity of mangroves on Hainan Island were estimated. The annual quantity of net growth was then inferred from the net primary productivity of mangroves. • Annual quantity of the net growth of agricultural ecosystems: Here the biomass of the main crops grown on Hainan in 2002 were used as the standard for the net production of the island’s agricultural ecosystem. The main crops included rice, soybeans, peanuts, gingili, sugarcane, vegetables and melons. The relationship between crop biomass and economic production is shown in the following equation:
Q = B·(1–R) / f
(10)
Q, crop biomass; B, economic production; R, water content of economic production; f, economic coefficient. • Annual quantity of the net growth of the grass ecosystem: According to Hainan Island regional agricultural reports the productivity of the grass ecosystem is 33–66 kg of fresh grass ha -1 (Bureau of Statistics of Hainan Province 2003). The annual quantity of the net growth of the grass ecosystem can be calculated by the following equation:
Qn = ((1–W)·Qf·S )·(1+1/R)
(11)
Qn, annual net growth quantity of grass ecosystem; W, water content in fresh grass; Qf, annual fresh grass production per Mu; S, area; R, ratio of roots and stems. • Net quantity of the growth of mountainous coppice forest: The net quantity of the growth of mountainous coppice forest can be determined from the cumulative amount using Equation 12. P = (Q·ρ) / (Y·R) (12) P, productivity (t ha-1); Q, accumulation amount (m3 ha-1), ρ, proportion of dominant trees (g cm-3); Y, ages of trees (a); R, merchantable volume tables. The cumulative amount of mountainous coppice forest
Table 2 Relative coefficient between biomass and the cumulative quantity of forest ecosystems. Type ai bi
Cunningha mia
Pinus
Eucalyptus
Broadleaf
0.40 22.54
0.52 33.24
0.79 6.93
0.63 91.00
Casuarina 0.76 8.31
Hevea 0.80 12.23
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in Jianfengling was 141m3 ha-1, in which the dominant tree species were Quercus and Castanopsis. The proportion of Hainan Castanopsis trees was 0.787g cm-3 (Research Institute of Wood Industry (CRIWI), Chinese Academy of Forestry 1982), and the proportion of Alpine Oaks was 0.960g cm3. 2.6 Assessment of ecosystem nutrient cycle maintenance service The nutrient cycle within the ecosystem operates among the biological systems, litter and soil resources. The most significant process is the nutrient exchange between organisms and soil. Many elements such as total nitrogen, available phosphorus, and available potassium participate in the ecosystem nutrient cycle maintenance service. The retention of nutrients in the soil resources was analyzed. With the aid of GIS, the cycling of macronutrients such as total nitrogen, effective phosphorus and effective potassium was quantified. Based on these values and using the shadow price method the amount of nutrient retention in the soil resources and subsequently, the value of the ecosystem’s nutrient cycle maintenance service, could be ascertained. 2.7 Assessment of the forest’s coastline windbreak service Hainan Island is located near the coastline of mainland China in the western Pacific. It is within the tropical monsoon zone where cyclonic winds often wreck havoc. Windbreak forests along the coastline play an essential role in retaining soil and water, resisting the destructive forces of wind, improving soil fertility, extending the farming area and protecting agricultural industry and human life. This study used the market price of reduced typhoon damage to assess the value of the coastline windbreak forest ecosystem.
3 Ecosystem service and ecological economic value on Hainan Island 3.1 Ecosystem product value The value of the ecosystem products of Hainan Island was 254.06×108 CNY in 2002. Agricultural net production and timber values were 229.23×108 CNY and 24.83×108 CNY,
respectively (Table 3). 3.2 Ecosystem’s soil conservation service Using GIS by Universal Soil Loss Equation (USLE)the amount of potential soil erosion, the actual amount of soil erosion and its spatial distribution characteristics were determined. • Potential amount of soil erosion: The potential amount of soil erosion on Hainan Island ranged from 0 to 170.00 t ha-1 y-1, but in 96.5% of the island it was below 25.00 t ha-1 y-1. The total amount of potential soil erosion on Hainan Island was 1.57×107 t y-1. The central mountain areas on Hainan such as Qiongzhong, Tongshi, Ledong Lingshui, and Changjiang, consist of long slopes and steep gradients where the risk of soil erosion is high and the potential amount of soil erosion was above 10.00 t ha-1 y-1 (Table 4). • Actual amount of soil erosion: The actual amount of soil erosion on Hainan Island ranged from 0 to 16.55 t ha-1 y-1, but in 96.2% of the island it was below 2.0 t ha-1 y-1. The amount of soil erosion in the middle mountain area was above 1.00 t ha -1 y -1, and was between 0 and 1.00 t ha-1 y-1 in the surrounding mesa, plain and valley areas. Using the value of 5.00 t ha-1 y-1 as the non-erosion standard, the plain and valley areas in the middle mountain area of Hainan Island are all considered non-erosion regions. The total amount of actual soil erosion on Hainan Island was 8.98×105 t y-1 (Table 4). • The ecosystem’s soil conservancy service: The annual soil conservancy capability was 1.48×107t. By comparing the average amount of actual soil erosion and average amount of potential soil erosion in all the ecosystems on Hainan Island, it was clear that the amount of soil held by the mountainous coppice, mountainous evergreen, mountainous rain, valley rain and tropical monsoon forests were all significant, with values above 10.0 t ha-1 y-1 (Table 4). • Assessment of the ecosystem’s soil conservancy value: Based on Equations (6), (7), and (8), if the average price of chemical fertilizer was 2549 CNY t -1, the forest’s economic benefit would be 263.58 CNY ha-1 y-1 and the sluice cost for reservoirs would be 0.67 CNY m-3
Table 3 Net wood cumulative quantity and value of Hainan Island forests per year. Dominant tree species
The net wood cumulative per year (m3 y-1) Young forest
Cunninghamia 9070.32 Pinus 13 071.09 Eucalyptus 2 636 927.02 Broadleaf 49 953.12 Casuarina 92 530.28 Hevea
Middle-aged forest
Mature forest
Value (CNY y-1) Young forest
6121.33 858.18 2 693 885.04 69 776.78 30 915.36 3 516 124.29 4 257 895.59 2 776 848.75 627 588 630.52 74 996.16 37 298.67 11 888 842.32 229 552.34 89 593.37 19 338 828.31 781 455.92
Middle-aged forest
Mature forest
1 407 906.36 296 072.79 14 443 794.29 9 614 676.96 783 452 788.01 766 410 254.45 13 799 292.52 10 294 434.02 36 957 927.38 21 681 595.06 159 417 007.68
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Table 4 Soil erosion and soil conservation of various ecosystems. Average soil erosion rate (t ha-1 y-1)
Total soil losses (t y-1) Ecosystem type Windbreak forest Valley rain forest Shrubs Crop land Tropical monsoon forest Tropical coniferous forest Plantation Mountainous evergreen forest Mountainous rain forest Mountainous coppice forest Savanna Timber forest Total
Area (ha)
Actual
Potential
Actual
Potential
Soil conservation (t ha-1 y-1)
63 471 3832 626 265 433 181 500 353 6792 548 329 36 482 99 728
6977.21 49.36 274 609.63 6541.03 20 435.32 5081.78 307 820.94 36 468.00 30 774.10
49 839.63 47 983.03 3 230 762.25 726 314.58 5 103 123.50 46 105.64 2 052 188.88 608 068.81 1 538 645.38
0.1099 0.0129 0.4373 0.0151 0.0407 0.7482 0.5586 0.9996 0.3086
0.7853 12.5217 5.1446 1.6767 10.1716 6.7882 3.7239 16.6667 15.4275
0.6754 12.5088 4.7073 1.6616 10.1309 6.0400 3.1653 15.6671 15.1189
6446 435 596 8132 2 768 607
10 356.06 196 204.36 3032.06 898 349.90
122 009.42 2 191 737.77 20 215.86 15 736 995.00
1.6063 0.4495 0.3726 5.6593
18.9250 5.0208 2.4844 99.3364
17.3187 4.5714 2.1118 93.6772
(Editorial Committee of State Report on Biodiversity of China Committee 1997). The value of the different ecosystems was demonstrated by their ability to prevent soil erosion and reduce wastelands, maintain nutrients and reduce silt loss (Table 5). The ecological economic value of the ecosystem of Hainan Island in preventing soil erosion was 7189.98×10 4 CNY, in which 46.39×104 CNY was a result of decreasing wastelands The value of maintaining nutrients was 6984.99×104 CNY, in which the values of maintained N, P and K were 6456.01×10 4 , 47.29×10 4 and 481.69×104 CNY, respectively. The value of reducing silt loss was 158.60×104 CNY. The ecological value of soil conservancy per unit varied according to the ecosystem type. The highest value was for the mountainous coppice forest, 142 CNY ha -1 y -1,
followed by mountainous evergreen, mountainous rain, valley rain and tropical monsoon forests with values of 120, 110, 70 and 49 CNY ha-1 y-1, respectively. 3.3 Ecosystem’s water-holding service By calculating litter fall and soil water-holding capability for all kinds of soil, and overlaying maps of the ecosystem and the soil types of Hainan Island, we determined the quantity of water held by the soil and its spatial distribution. Based on this information and the cost of reservoir sluices, a value for the water-holding service was determined using the shadow engineering method (Table 6). The mountainous coppice, valley rain, and mountainous evergreen forest ecosystems displayed great water-holding capabilities that were above 620 t ha-1 y-1. The water quantity held by the soil resources in the Hainan
Table 5 Economic value of ecosystem soil conservation.
Ecosystem type Windbreak forest Valley rain forest Shrubs Crop land Tropical monsoon forest Tropical coniferous forest Plantation Mountainous evergreen forest Mountainous rain forest Mountainous coppice forest Savanna Timber forest Total
Conservation (CNY y-1) Land Area (ha)
Silt decreasing (CNY y-1)
N (CNY y-1)
63 471 3832 626 265 433 181 500 353 6792 548 329 36 482 99 728
1238.98 1506.75 91 920.51 22 155.05 158 491.38 1269.91 54 215.86 18 426.53 48 128.10
6446 435 596 8132 –
3639.14 12 443.02 861 753.38 62 329.86 213 119.22 9 639 238.46 532.14 1819.50 62 748.95 463 854.21 1 586 017.44 64 560 146.16
P (CNY y-1)
K (CNY y-1)
Total (104 CNY y-1)
4236.33 63 900.72 858.44 6218.65 7.65 5151.92 244 147.50 1751.20 14 514.35 26.71 314 296.03 10 331 811.00 83 864.59 911 957.25 1173.38 75 752.88 1 934 335.20 18 113.95 193 013.10 224.34 541 916.13 21 707 772.00 153 843.14 1 799 603.00 2436.16 4342.09 121 606.20 1202.51 9338.22 13.78 185 375.69 5 364 568.50 47 908.77 496 030.41 614.81 63 004.29 4 086 307.25 26 298.44 184 475.98 437.85 164 560.34 10 141 957.00 64 656.52 517 943.44 1093.72 5540.20 34 332.94 91.77 68 330.56 644 289.47 1062.73 501.39 5164.64 7.08 472 869.71 4 816 881.45 7189.98
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Table 6 Water-holding ability of ecosystem soil and its value.
Soil type
Litter fall waterholding (t y-1)
Soil waterholding (t y-1)
Coastal sand soils Fluvo-aquic sand soils Brown latosols Red and yellow latosols Mountainous latosol red earths Mountainous brown latosols Mountainous red and yellow latosols Mountainous yellow earths Paddy soils Saline soils Torrid red soils Bog soils Total
183 884.99 353 692.01 700 857.92 1 259 507.52 533 753.87 625 356.48 100 175.00 1 747 235.94 0.00 0.00 24 775.90 0.00 5 529 239.63
52 865 981.73 243 285 577.88 836 331 758.71 2 749 757 371.26 365 024 999.77 796 734 526.82 1 803 806 996.83 369 669 464.57 62 653 168.46 1 460 234.99 183 215 708.96 647 211.19 7 465 453 001.16
Total waterholding (t y-1) 53 049 866.72 243 639 269.89 837 032 616.63 2 751 016 878.78 365 558 753.64 797 359 883.30 1 803 907 171.83 371 416 700.51 62 653 168.46 1 460 234.99 183 240 484.86 647 211.19 7 470 982 240.79
Value (104 CNY y-1) 3 554.34 16 323.83 56 081.19 184 318.13 24 492.44 53 423.11 120 861.78 24 884.92 4 197.76 97.84 12 277.11 43.36 500 555.81
Table 7 C fixation ability and its value of various ecosystem. Net primary Cosystem type Windbreak forest Valley rain forest Shrubs Mangrove Crop land Tropical monsoon forest Tropical coniferous forest Plantation Mountainous evergreen forest Mountainous rain forest Mountainous coppice forest Savanna Timber forest Total
productivity -2 -1 Area (ha) (g m y )
Net primary production (104 t y-1)
CO2 fixation (104 t y-1)
C fixation (104 t y-1)
Value (104 CNY y-1) Forestation cost
C tax
63 471 3832 626 265 4958 433 181 500 353 6792 548 329 36 482 99 728
700 2 200 700 2 950 650 1 600 1 110 700 1 912 2 210
44.43 8.43 438.39 14.63 281.57 800.56 7.54 383.83 69.75 220.40
72.42 13.74 714.57 23.84 458.96 1 304.92 12.29 625.64 113.70 359.25
19.75 3.75 194.88 6.50 125.17 355.89 3.35 170.63 31.01 97.98
5 153.01 977.66 50 844.90 1 696.32 32 657.09 92 850.99 874.49 44 517.13 8 090.27 25 562.27
24 521.74 4 652.43 241 956.65 8 072.33 155 405.94 441 851.84 4 161.45 211 844.55 38 499.34 121 643.68
6446 435 596 8 132 –
880 900 2 200 –
5.67 392.04 17.89 2 789.13
9.25 639.02 29.16 480.76
2.52 174.28 7.95 1 297.66
658.18 45 469.18 2 074.87 311 426.36
3 132.09 216 375.08 9873.71 1 481 990.83
ecosystem was 7.47×109 t y-1, with a value of 50.06×108 CNY y-1.
between the two values stated above.
3.4 Ecosystem’s CO2 fixation service
Using the Hainan soil survey data (Soil Station of the Bureau of Agriculture in Hainan Province 1994), all physical characteristics of the soil resources including the average bulk density and total thickness, and nutrient concentrations of total nitrogen, effective phosphorus and effective potassium could be calculated (Table 8). With the support of GIS, the spatial distribution characteristics of all nutrients in the Hainan Island ecosystem could also be determined. Using the shadow price method and assuming the average price of chemical fertilizer was 2549 CNY t-1 (Editorial Committee of State Report on Biodiversity of China Committee 1997), the total value of soil nutrients in
The amount of annual fixed CO2 was 4480.76×104 t (Table 7), which can be converted into a quantity of C fixation of 1297.66×104 t. Assuming the cost of forestation was 260.90 CNY t-1 C (the price being the same as in 1990) and the Swedish tax rate was 150 Dollar t-1 C (Editorial Committee of State Report on Biodiversity of China Committee 1997) (100 Dollars = 827.7 CNY), the total value of C fixation by the ecosystem of Hainan Island was 31.14×108 CNY or 148.20×108 CNY for forestation costs and carbon tax methods, respectively. Thus the total value of C fixation by the ecosystem on Hainan Island is
3.5 Ecosystem’s nutrient maintenance service
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Table 8 Quantity of nutrilites held in the ecosystem soil and its value. Soil type Coastal sand soils Fluvo-aquic sand soils Brown latosols Red and yellow latosols Mountainous latosol red earths Mountainous brown latosols Mountainous red and yellow latosols Mountainous yellow earths Paddy soils Saline soils Torrid red soils Bog soils Total Value(104 CNY y-1)
N (t y-1)
P2O5 (t y-1)
612 101.46 1 177 341.30 4 765 513.49 19 989 188.21 3 652 648.56 4 252 138.17 13 001 464.44 2 369 793.04 314 126.28 20 838.44 1 268 398.24 13 090.71 51 436 642.33 13 111 200.13
the Hainan Island ecosystem was 1952.61×108 CNY. 3.6 Ecosystem’s windbreak service There are 1×104 km of windbreak forests along the 1.8×104 km coastline of China, which help decrease the economic loss of the littoral zone from typhoons by 9–12×108 CNY. Specifically, the value of the windbreak service from the 1500 km of windbreak forests on Hainan Island is estimated to be between 1.35×108 and 1.80×108 CNY. 3.7 Integrated assessment of ecosystem services on Hainan Island Through a quantitative assessment of the substantive and economic quantities of ecosystem services on Hainan Island, the Hainan Island ecosystem product value was estimated as 254.06×10 8 CNY, while the value of the regulating services was between 2035.88×10 8 and 2153.39×108 CNY (Table 9); a value eight times greater than the ecosystem product value.
4 Discussion According to the latest studies, ecosystem services have been divided into provision services, regulating services, cultural services and supporting services (Millennium Ecosystem Assessment Board 2003). Ecological regulating services refer to soil conservancy, water-holding, pollutant decontamination, CO 2 fixation, nutrient cycle, climate regulation, bio-control of harmful species, disaster prevention and windbreak function (Millennium Ecosystem Assessment Board 2003; Costanza et al. 1997). In this study, the ecological regulating services were selected to determine the indirect value of ecological regulating services in the Hainan Island ecosystem. They were then compared with the product value. Due to the limitation of basic data and research, the services selected were not comprehensive and our assessment was not complete.
176 325.52 339 151.81 1 955 994.34 4 201 931.45 720 240.56 1 745 280.59 9 458 831.08 332 333.44 72 792.19 2 858.31 327 027.17 1 795.59 19 334 562.06 4 928 379.87
K (t y-1) 65 492.34 125 970.67 835 743.04 2 160 993.32 600 200.47 745 710.80 743 953.01 232 633.41 22 397.60 3 933.58 291 988.54 2 471.07 5 831 487.84 1 486 446.25
However, the significance of ecological regulating services is indisputable since their contribution to humans (soil conservation, water-holding, CO2 fixation, nutrient cycle maintenance, windbreak function and disaster prevention) was eight times greater than the product value. Regulating services for different ecosystems were variable (Farber et al. 2002; Montoya et al. 2003). As far as soil conservancy was concerned, mountainous coppice forest, mountainous evergreen forest, mountainous rain forest, valley rain forest and tropical monsoon forest ecosystems played significant roles. The water-holding capability of mountainous coppice forest, valley rain forest and mountainous evergreen forest ecosystems was more than 620 t ha-1 y-1. Due to the high net primary productivity, mangrove, mountainous rain forest and valley rain forest ecosystems have distinguishing CO2 fixation capability. The tropical forest ecosystems have great regulating services (Kaiser and Roumasset 2002) and are obviously an essential part of maintaining Hainan ecological integrity. Moreover, different areas or ecosystems have distinct ecological regulating services, and these services correlate with the area (Konarska et al. 2002). During an assessment of regional services, other Table 9 Assessment of the ecological regulating services of the Hainan Island ecosystem.
Service Soil conservancy Water-holding C fixation Nutrient cycle Windbreak function Total
Material quantity (104 t y-1) 1 480.00 747 098.22 4 480.76 7 660.27 — —
Monetary quantity (108 CNY y-1) Lower limit Upper limit 0.72 50.06 31.14 1 952.61 1.35 2 035.88
0.72 50.06 148.20 1 952.61 1.80 2 153.39
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海南岛生态系统调节功能及其价值评估 欧阳志云，金 羽，赵同谦，郑 华 中国科学院生态环境研究中心城市与区域国家重点实验室，北京 100085
摘要：生态系统服务功能是指生态系统与生态过程所形成及所维持的人类赖以生存的自然环境条件与效用，主要包括生态系 统产品提供功能、调节功能、支持功能与文化功能。对生态调节功能的认识与评价是区域生态环境保护与资源开发的基础。本文 以海南岛为例，探讨了基于生态系统结构与过程的生态调节功能评价方法。在研究中，将海南生态系统类型划分为沟谷雨林、山 地雨林、热带季雨林、山顶矮林、山地常绿阔叶林、热性针叶林、灌丛、热作园、用材林、防护林、红树林、热带草原、耕地等 13类，分析与评价了海南岛各类生态系统在水源涵养、土壤保持、营养物质循环、固碳、防风减灾等方面的调节功能及其经济价 值。研究表明，2002年海南岛生态系统所提供的生态调节功能的价值为2035.88×108 – 2153.39×108元，而生态系统产品价值仅为 254.06×108元，生态调节功能价值是其产品价值的8倍多。 关键词：生态系统服务功能；生态调节功能；海南岛
