Sustainable management of ecosystem: Integration of life cycle and scenario approaches Yue Moriizumi and Hiroki Hondo Graduate School of Environment and Information Sciences, Yokohama National University 79-7 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
[email protected] Keywords: Life cycle approach, Mangroves, Scenario approach, Sustainability, Trade-off ABSTRACT This study proposes a new method that integrates life cycle approach and scenario approach in order to assess sustainability of ecosystem management considering both environmental and socio-economic impacts. The developed method is applied to explore a harmonious balance between conservation and use of mangroves in Thailand, especially focusing on two main dimensions: local socio-economic (e.g. employment, income) and global environmental dimensions (e.g. climate change). Introduction Ecosystem produces a wide variety of goods on which human activity depends and provides fundamental life-support services. For example, in the case of mangrove ecosystem, the following values are recognized; nutrient retention and water purification, erosion control and protection against the forces of storm and flood. These ecological functions indirectly support the well-being who live in coastal areas. In addition, mangroves play an important role in supplying goods and services, such as food and drink, medicine, on-site fisheries products, firewood, charcoal, timber and construction materials. These direct use values of mangroves support to sustain and improve the livelihoods of local communities. Another crucial function of mangroves is to serve as the basis of the food chain and as habitat for many species of fish, shellfish, insects, birds and mammals. Thus, mangroves are rich in biodiversity and highly productive ecosystem. Furthermore they act as the storage of carbon dioxide. As above mentioned, ecosystem offer a great deal of benefits to human beings and the ‘benefits’ range very widely, that is, multidimensional (environmental, social and economic), time scale-dependent (short-term and long-term) and context-dependent (local, national and global). Therefore the activity to get one benefit might result in losing another benefit, and/or the requirement of obtaining the benefit at one level might lead to cost of another level. Such trade-offs between benefits make it difficult to manage ecosystem sustainably. For instance, a management option that exclude local communities from access to the ecosystem to protect them is effective from the global and environmental aspects but is not sustainable from local and the socio-economic aspects because there is no consideration for the livelihood of the communities dependent on the ecosystem. Contrary to this, local communities could make a profit from the excessive utilization of ecosystem in short-term but this option is also not sustainable from the environmental aspects. Therefore sustainable management of ecosystem needs to consider trade-offs and balance between multidimensional benefits dependent on time and context, which requires an assessment method that can handle a wide range of benefits simultaneously. The aim of this study is to develop and demonstrate a method to assess the sustainability of ecosystem management characterized by complexity and diversities. We aim to offer valuable information for decision making of how to manage ecosystem. Method This study proposes a new method that integrates life cycle approach and scenario approach in order to assess sustainability of ecosystem management. The framework of the developed method, which is a step-wise iterative procedure that includes the following four steps, is shown in Figure 1.
Step 1: Identifying impacts of ecosystem management First step is the investigation of available options of ecosystem management and identification of impacts (i.e., costs and benefits) that would occur when options are implemented. The number of options is not limited. The identification is based on multidimensional aspects, that is, environmental, social and economic because sustainability of ecosystem management should be assessed from various aspects. It is required to select impacts which strongly influence decision-making on how to balance conservation and utilization of the ecosystem. Moreover, each impact must be measurable. The identification and selection of impacts allows for breaking the complex problems down into manageable pieces. Step 2: Scenario Planning The second step is to create baseline and alternative scenarios. Various conditions and constraints related to management options would be identified and translated into scenarios, which is a description of the assumption for quantitative analysis in the next step. Scenarios are developed with reference to the present and future management of ecosystem. Moreover, scenarios are created considering whether impacts are local, national or global scales and whether impacts are short or long terms. In the process of designing scenarios, the validity of impacts identified in step1 should be checked. That is, the iteration process between step1 and step2 is required. Step 3: Quantitative Analysis This step that creates quantitative information involves the determination of a system boundary and a functional unit, data collection, and inventory analysis. Each scenario developed in step2 is analyzed from life cycle perspective in terms of impacts which were identified in step1. It is crucial to make detailed and precise analysis using primary and secondary data at all stages in a life cycle of a management option. Accurate and reliable information is needed in order to make an appropriate decision. Therefore this step of quantifying impacts of each scenario is the most important among four steps. Step 4: Sustainability Assessment The final step is to assess and interpret the results of inventory analysis performed in step 3. If potential options that may be more sustainable are recognized through the comparison between the calculated results, scenario planning and quantitative analysis are performed again to develop new alternative scenarios corresponding to the potential options.
Identifying impacts of ecosystem management
(1)
(2)
Scenario approach
Scenario Planning
(3)
Life cycle approach
Quantitative Analysis
(4)
Sustainability Assessment
Sustainability -Environmental -Social -Economic
-Scale of the interaction (Global / National / Local) –Time scale (short term / long term)
-Defining System Boundaries -Data collection -Determination of functional unit -Inventory analysis
-To compare and interpret management options -To explore more sustainable management options
Information for decision making
Figure 1: The framework and procedure of the developed method
Case Study We present a practical analysis to illustrate the effectiveness of the proposed methodology. The management of mangroves planted in waste land is selected as a case study of the application of the method. Mangroves are salt tolerant ecosystem formed by an assemblage of various trees and shrubs. They are found along coastal areas and estuaries in tropical and subtropical regions. The research area is the Yeesarn village in the Amphawa district of Samut Songkhram province, which is located about 60km west of Bangkok, Thailand. Step 1: Identifying impacts of the mangrove management In the context of mangrove management in Thailand, a key issue is a conflict between the local socio-economic benefits and global environmental benefits. Mangroves have traditionally provided a wide range of socio-economic benefits to local people. Therefore mangroves are valuable regional resources which have a real relevance for local people’s daily life and support their livelihood. On the other hand, from the viewpoint of global environment, the benefits concerning biodiversity preservation and climate change mitigation are extremely valuable. Plantations especially for climate change mitigation are increasing recently. For these reasons, we select the following impacts of the mangrove management activities: • Amount of CO2 emitted from the activities and CO2 absorbed by mangroves, • Number of employment and amount of income in local communities. Step 2: Scenario Planning We design the following two scenarios based on the identified impacts in step1. • Scenario A : Preservation scenario, • Scenario B : Conservation and sustainable use scenario. Scenario A assumes that any utilization is not allowed after plantation. On the other hand, Scenario B permits charcoal making from mangroves. The main reason why charcoal making is chosen as an option of mangrove management is that mangrove charcoal is produced by the traditional technology in mangrove areas so that this option is familiar to local people and has potential for sustainable use. And mangrove charcoal is still in demand in spite of high price because of their quality. Moreover, it can be regarded as a substitution of fossil fuel. This case study assumes that evaluation period is 20 years. The detailed assumption of plantation in two scenarios is summarized in Table 1. Plantation area is divided into 10 plots and mangroves are planted on a plot every year. Scenario A assumes that mangroves are preserved after plantation, and thus plantation is over at project year 10.. Scenario B assumes that 10 year-old trees are cut down after plantation, and a cutover plot is reforested at the same time (based on the concept of ‘normal forest’). Thus, the production of charcoal and reforestation start at project year 11. Trees are planted at higher density in scenario B because straight trees are desirable for charcoal making. Step 3: Quantitative assessment Figure 2 shows life cycle of the activities for two scenarios. Charcoal produced substitutes Liquefied Petroleum Gas (LPG) used as fuel in restaurants and households etc. Hence, the production of charcoal can reduce the consumption of LPG. Primary data and information on each process of life cycle of the activities for each scenario are collected. Concretely, inputs (energy, materials, labor) and outputs (products) in each process are gathered based on field surveys in Thailand. And then the yearly inputs to the system are estimated in each scenario and life cycle impacts over 20 years for two scenarios are evaluated under the assumption in step2. Table 1: Assumption of plantation in two scenarios Scenario A : Preservation Plantation Area (Total) Plantation Area (per year) Plantation Method Plantation Density Number of Plants (per year) Cutting Age
Scenario B : Conservation and Sustainable use
1,000ha
1,000ha
100ha/year
100/year
Transplantation
Direct Plantation
4,850 plants/ha
25,000 plants/ha
485,000 plants/year
2,500,000 plants/year
-
10 years
Seed Collecting
Seed Collecting Seed Transport
Seed Transport
Seedlings
Seed Storage Plant (Seed) Transport
Plant (Seed) Transport
Plantation
Plantation Substitute
Crude Oil Production
Cutting Raw material Transport Charcoal Production
Crude Transport Oil Refining
Charcoal Transport Charcoal Consumption
LPG Distribution LPG Consumption
Scenario B: Conservation and Sustainable use
Scenario A: Preservation
Figure 2: Life cycle of the activities for two scenarios
CO2 emission and removal Fig. 3 shows the amount of CO2 absorbed by mangroves in scenarios A and B. Gross CO2 removals by sink for 20 years in scenarios A and B are estimated to be 343x103 and 602x103 t-CO2, respectively. In scenario A, the annual CO2 removal peaks at project year 14 and then decreases year by year. On the other hand, the annual CO2 removal in scenario B increases until project year 10, and after that becomes constant because a given trees are reforested after project year 11. The amount of CO2 emission for 20 years in scenario A and B are estimated to be 12 and 91,045t-CO2, respectively. It is made clear that transport processes account for a large proportion of total CO2 emissions in the plantation processes in both scenarios. In the charcoal production processes, the combustion of fuel wood at the production of charcoal causes CO2 emission (17,761t-CO2). In contrast, since charcoal substitutes LPG, CO2 emission associated the LPG production is reduced due to the decrease in the LPG consumption. Furthermore, CO2 are also emitted from the charcoal combustion (153,990t-CO2) while CO2 emission from the use of LPG decreases due to the assumption that charcoal substitutes LPG. 50,000 Gross removal [Scenario A] Gross removal [Scenario B]
CO2 removal [t-CO2 / year]
45,000 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 0 1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 Project year
Figure 3: Gross CO2 removal at each project year for Scenarios A and B
Finally, the net CO2 removal is estimated by taking CO2 emission away from gross CO2 removal. Fig. 4 indicates the net CO2 removals for two scenarios. The net CO2 removals for scenario A and B are estimated to be 343x103 and 511x103 t-CO2, respectively. Employment The activities in life cycle systems create the local employment. The created employment is estimated to be 607 and 5,512 persons in scenarios A and B, respectively. It should be noted that while Scenario A provides no employment opportunities after project year 11, scenario B constantly creates jobs over 20 years. Income Plantation and charcoal production increase the incomes of local people. The estimated total incomes for 20 years in scenarios A and B are 60 million and 416 million Baht, respectively (Fig.5). Besides, the average income per capita is calculated from total employment and total income. The average personal incomes per capita are 98,640 Baht in scenario A and 75,403 Baht in scenario B. Although total income in scenario A is less than that in scenario B, average income per capita in scenario A is more than that in scenario B. This is attributed to the difference in wages among processes. The values in both cases are higher than that of Samut Songkharam province (68,445Baht).
600,000
Removal
500,000
Emission
400,000
[t-CO2 / 20years]
CO2 removal
700,000
601,581
300,000 200,000
342,949
100,000 0 -12
-100,000
-91,045
-200,000 Scenario A
Scenario B
342,937 t-CO2
510,536 t-CO2
Net CO2 removal
Figure 4: Net CO2 removal for 20 years for scenario A and B
Income of Employees [100 million Baht / 20years
450
416 Million Baht
400
Charcoal Transport
350
Charcoal Productoin
300
Cutting and transport
250
Plantation
200
Plant (seed) transport Seedlings
150 100
Seed Collecting 60 Million Baht
50 0 Scenario A 98,640 B/capita
Scenario B 75,403 B/capita
Samut Songkhram: 68,445B / capita
Figure 5: Total income for 20 years and average income per capita
Conclusion and discussion In this study, we have proposed a method to contribute to decision-making about the management of ecosystem and carried out the empirical analysis using the method. In the case study, we have designed two scenarios about conservation and utilization of mangroves and estimated the amount of CO2 emitted and absorbed, number of employment and the amount of income that generated by these activities. The results of this case study show that the option of scenario B has a potential to be one solution for sustainable management of mangroves. This option, however, also has the following two problems. 1) no consideration of biodiversity conservation 2) no examination of the feasibility The former problem is that single species plantations, which is a plantation method that we assumed in scenario B, may have a negative effect on biodiversity conservation. And the main issue of the latter problem is that there is no income until charcoal making starts under the assumption of scenario B. In addition, in order to turn the management of ecosystem into a business, there is a need to make it clear how to distribute the costs and benefits. We now plan to propose new options that have a potential to get over the problems mentioned above as step 4 and aim to provide an available information for decision making for sustainable management of ecosystem. Acknowledgement The authors would like to thank Dr. Sonjai Havanond, Mr. Somsak Piriyayota, Mr. Pisake Salikul, Dr. Noparat Bamroongrugsa, Dr. Vipak Jintana, Dr. Yoshiaki Kitaya, Dr. Naohiro Matsui, Mr. Makoto Nogami, Mr. Katsushi Hatayama, and Mr. Yoshihiro Ideta for their helps with field surveys in Thailand. This work was funded in part by KANSAI Electric Power Company, Japan. References [1] T Nakamura, T Nakasuga (1998). A Guide to Mangroves., Mekon, Tokyo (in Japanese). [2] FAO (1994). Mangrove forest management guidelines., FAO Forestry Paper No.117, Rome. [3] Pesonen HL, Ekvall T, Fleischer G, Huppes G, Jahn C, Klos ZS, Rebitzer G, Sonnemann GW, Tintinelli A, Weidema BP, Wenzel H (2000). Framework for Scenario Development in LCA. The International Journal of Life Cycle Assessment, 5 (1) 21–30 [4] Fukushima Y, Hirao M (2002). A Structured Framework and Language for Scenario-Based Life Cycle Assessment. The International Journal of Life Cycle Assessment, 7 (6) 317-329 [5] Hondo H, Moriizumi Y, Sakao T (2006). A Method for Technology Selection considering Environmental and Socio-Economic Impacts: Input-Output Optimization Model and its Application to Housing Policy’ The International Journal of Life Cycle Assessment, 11(6) 383-393
