Economic valuation of mangrove ecosystems at u minh ha national park, vietnam

Nội dung text: Economic valuation of mangrove ecosystems at u minh ha national park, vietnam

1. ECONOMIC VALUATION OF MANGROVE ECOSYSTEMS AT U MINH HA NATIONAL PARK, VIETNAM Nguyen Huu Dung Department of Natural Resources Economics. National Economics University Email: nguyen.huudung@neu.edu.vn. Mobile phone: 0961151148 Abstract Mangrove ecosystems provide a wide range of both direct and indirect use values to coastal communities in developing countries. The full value of mangrove products and services is not yet recognized and is therefore often ignored in development planning. As a result, decisions are made which favour commercial developments over mangrove conservation. The direct use value for U Minh Ha mangrove forest is not well understood but is considered to be high and important to about 80% of the local people in the area. This report presents an economic value of direct uses of mangroves at U Minh Ha, to support policy makers identify an economically optimal integrated management strategy for the ecosystem. The direct uses of the mangrove ecosystem were examined through a survey of the local people, in which 5% of total U Minh Ha population was represented in the survey. Use rates for firewood, charcoal, construction poles, fishing gears, honey, medicinal plant, fish, crabs and prawns were quantified, and values were ascribed according to current commodity prices in local market. With a population of whom 80% depend on the ecosystem for their livelihood, if the extraction rate is not checked, all of U Minh Ha mangrove forest will be lost in about 52 years. Revenues from the mangrove wood products result in an annual benefit to the community of 526 US$/ha and 1,216 US$/ha from fish/shellfish products. Income obtained from the mangrove ecosystem contributes 51% to total annual per capita income. Moreover, the community recognizes importance of the ecosystem to their livelihood and showed willingness to participate in its management and conservation. Key words: Economic valuation; mangrove ecosystems; U Minh Ha National Park. 1. Introduction Mangroves are evergreen types of forests occurring along the coastlines of tropical and subtropical regions mainly along deltas and bays where fresh-water rivers enter the sea. These forests are characterized by trees, shrubs and vines that thrive in brackish waters of varying salinity. Mangrove trees can grow to a height of up to 45m, producing dense, closed canopy forests. These mangroves provide important ecological and socioeconomical functions to coastal societies. For example, mangroves are important for conservation of biological diversity including a number of endangered mammals, reptiles, amphibians and birds, protection of coral reefs, sea grass beds and shipping lanes against siltation through their immense root system (Michelle et al., 2003). In addition, they 447
2. provide habitat, spawning grounds and nutrients for a variety of fish species, molluscs and crustaceans. Timber harvested from the trees benefit local people as construction material, firewood and charcoal. Moreover, mangroves function as a shelter belt for coastal zones during storms, cyclones and tsunamis. Area with dense mangrove forests suffered less human losses and property damage than areas without mangroves (Thampanya, 2006). However, conversion of intertidal land for marinas, ports and adjacent industrial and housing developments has resulted in destruction of significant areas of mangroves. In addition, mangrove environment has suffered substantially from upland agricultural mismanagement, large scale deforestation and water resource developments, oil spills, pollution and eutrophication. Losses of mangroves in U Minh Ha have largely been attributed to over-harvesting for timber and fuel wood, conversion for aquaculture, rice farming, salt production and infrastructure (Valiela et al., 2001). Various reports (Semesi, 1998; Kairo et al., 2001) have indicated that extensive bare lands occur as a result of indiscriminate cutting of mangrove trees. Surveys at U Minh Ha have cited poor management and unsustainable utilization of the ecosystem by local people. The seven mangrove tree species found in the region i.e. Rhizophora mucronata, Avicennia marina, Sonneratia alba, Ceriops tagal, Xylocarpus granatum, Bruguiera gymnorrhizae and Lumnitzera racemosa were noted to be showing signs of depletion, despite government’s involvement in protection and management of the ecosystem. To successfully address the problem of unsustainable utilization of natural resources, government intervention is required but this needs to be justified by providing data on rate of harvest of the natural resources in order to determine the level of exploitation and the overall status of the natural resources. Additionally, information on economic values of the mangrove ecosystem is important in determining how the ecosystem contributes to economic interests of the local communities, and as well provide inputs for policymakers so that the policies they develop reflect value of the resources and issues related to their management and conservation. Though little research on conservation of mangroves in the area has been done, the scanty information about utilization of the mangrove forest by local people has not been linked to policy making. Besides, no study on total economic value of the mangrove ecosystem has been carried out and that leaves a gap in knowledge of total economic values. This gap of information has contributed to improper implementation of conservation strategies by the government, and consequently threatens livelihoods of 70% of the local population living around the area. The main goal of this study is to provide information on economic benefits of U Minh Ha mangrove ecosystem, to support environmental managers and policy makers to identify an economically optimal integrated management strategy for the ecosystem. The research focused on the mangrove forest, and relied on data obtained from a household 448
3. survey conducted within the community. However, secondary data from related studies and government reports were used for additional information. The research concentrated primarily on direct uses of the mangrove ecosystem. 2. Study site U Minh Ha National Park has been established on the basis of merging Vo Doi Nature Reserve of special use forest and a part of U Minh Ha melaleuca forests. It has a total area of over 8,000 hectares. This is used for conservation and development of many diversity animal and plant ecosystems. U Minh Ha National Park brings typical features of Southern mangrove forest, trees in U Minh are mainly mangrove melaleuca, pimply lasia (a type of water grass), eleocharis, reed and vines with varied fauna such as: freshwater fish, pangolin, wild boar, deer, monkey, squirrel, lizard, python, snake, turtle Many rare species listed in Vietnam Red Book should be preserved. A primary factor of the natural environment that affects mangroves over the long term is sea level and its fluctuations. Other shorter-term factors are air temperature, salinity, ocean currents, storms, (Snedaker, 1993) shore slope, and soil substrate. Most mangroves live on muddy soils, but they also grow on sand, peat, and coral rock. If tidal conditions are optimal, mangroves can flourish far inland, along the upper reaches of coastal estuaries. Mangroves vary in height according to species and environment, from mere shrubs to over 40 meter trees. The prop roots of some mangrove species, such as Rhizophora, commonly referred to as red mangrove and the pneumataphores of others contain many small breathing lenticels. These allow oxygen to diffuse into the plant, and down to the underground roots by means of air space tissue in the aerenchyma. The lenticels are inactive during high tide. 3. General model Economists typically classify ecosystem goods and services according to how they are used and the main framework used is the Total Economic Value (TEV) approach (Pearce and Warford, 1993). These include; (i) direct use value; (ii) indirect use value; (iii) option value and (iv) non-use value. The first three are generally referred together as use value. Direct use values are the easiest to value, since they usually involve observable quantities of products whose prices can be observed in the marketplace. Recreation is also relatively easy to value as the number of visits is directly observable though assessing the benefit received by visitors is more difficult. Furthermore, it is hard to calculate the economic value of indirect uses since the quantities of services provided such as the amount of carbon stored in biomass are often hard to measure. While their contribution to production of marketed goods and services may be significant, it is often difficult to distinguish it from that of other marketed inputs to production. Moreover, many of these services do not enter markets at all, so their price is also difficult to establish. Non-use 449
4. value is the most difficult type of value to estimate, since it is not reflected in people’s behaviour and is thus unobservable. However, surveys have been used to estimate its value in which people are asked how much they are willing to pay (Willingness to Pay Method) for conservation of an endangered species or ecosystems, which they themselves do not use directly. 4. Data collection and valuation Techniques Techniques for valuing natural ecosystem services are still relatively new. Putting a monetary value on a natural ecosystem helps to demonstrate why its survival is important (Turner et al., 2003). Economic values can be calculated from the cost of the products (e.g. fish) and services (e.g. tourism) derived from an ecosystem, or from the cost of replacing a service (e.g. building seawalls where natural storm protection has been lost). A survey of 120 households in six villages around U Minh Ha area was undertaken from January 2018 to March 2018. Villages were chosen from the 3 administrative locations of the ecosystem and at various distances to the forest, to provide a representative sample for utilization of the entire ecosystem. Households neighbouring the mangrove ecosystem were visited and from each village, 20 households were approached. Out of 120 families interviewed, 101 provided useful information for data analysis. Total population of sampled households (1,219 persons) indicated 5% of entire the population in the buffer zone, which currently stands at 23,000 people. The average number of persons per household in the region was 12. Most villagers interviewed were fishermen who had low education level, indicating exclusion from margins of labour markets and low monthly income of 4 million VND per person. One person per household was interviewed to avoid repetition from members of the same household. A local guide from the community for each village led the process to necessitate easy conversation with the respondents. 4.1. Identification and Quantification of Local Direct Uses To assess whether U Minh Ha mangrove forest is useful to local people, a semi- structured questionnaire with multiple-choice as well as some open-ended questions was used in which questions were aimed at providing information regarding various uses of the ecosystem, size of each household, amount of products collected and frequency of harvesting. In some situations, like for easily noticeable uses, visual observations were used. For quantification of local uses, amount of products collected was converted to one unit (kilograms) for statistical purposes. To illustrate the procedures used, Table 3 shows examples of the steps undertaken. 450
5. Table 1: Weight estimation procedure for mangrove products collected at U Minh Ha mangrove ecosystem based on a survey done in 2018 Estimate Parameter Unit weight Method of Estimation Notes (kg) Firewood Bundle 5 A scale was used to weigh 3 bundles, and an average weight taken Construction Pole 10 A scale was used to poles weigh 3 poles, and an average weight taken Fishing gears Bundle 30 A scale was used to weigh 3 bundles, and an average weight taken Charcoal Bag 90 1bag of charcoal was Assuming all weighed using a scale charcoal is packed in bags of same size Honey Liter 1.44 Means of metric Assuming conversion honey density value of 1.44g/ml (Krell, 1996). Medicinal Bunch 1 Quoted by respondents plant Fish kg kg Quoted by respondents Crabs kg kg Quoted by respondents Prawns kg kg Quoted by respondents Source: Author’s calculation 451
6. Assuming an average of 30 days in a month, total amount of products collected on monthly basis for each household was calculated by multiplying the amount of product collected per visit to the forest by frequency of harvest (daily, weekly, monthly, yearly etc) and then divided by number of persons within a household to determine monthly per capita quantity of forest resources used. Consequently, regarding extraction of products in the six villages, the rates of annual per capita extraction and the rate of annual extraction rate per village are used. 4.2. Estimation of Direct Use Value Data obtained from the questionnaires was further analyzed for estimation of direct use value of the ecosystem. Information regarding prices of materials used in harvesting was received from respondents, in addition to consultations with shop owners. Besides, few individuals among the respondents were interviewed concerning lifespan of tools used in harvesting. Minimum hourly wage rates used to calculate cost of time and price for construction poles were got from the Ministry of Labour and the Forest Department respectively. Using the following formula, as explained by Turner et al. (2003) in his study, direct use value was estimated by calculating net income generated by local communities in terms of products extracted directly from the ecosystem. Local Direct Use Value=Net income = ∑ 푃푖푄푖− 푖 where Pi =prices of product I; Qi =amount of product i being collected; Ci =costs involved in the collection of product i. Gross benefit was estimated by calculating total quantity of all products collected on monthly basis and then multiplied by market prices of each. For all products, market price was used to determine gross income generated. To derive net benefits, it was necessary to determine extraction costs which included cost of time spent walking to the forest, in harvesting products, and cost of tools such as axes or knives. 5. Evaluation of Impacts of Local Direct Uses to the Ecosystem Information on impacts of local direct uses on the mangrove ecosystem, and their concurred consequences to the local communities, was gathered from previous surveys carried out in the area. Further information was obtained by analysing responses from the questionnaires. Questions were posed to help respondents, in accordance to their knowledge to identify current threats to the mangrove ecosystem, and to give their views on causes of the threats. We assume that the average number of 12 persons per household was similar in all villages and representative for the entire community; Market prices for all products were used in valuation of the ecosystem as there was no data on proportions of products sold in markets to subsistence food; Fish/shellfish products collected are linked to the 452
7. mangrove ecosystem as feeding or spawning grounds; Market prices are not distorted; Transport costs to commercial centers were not considered as most respondents especially fishermen indicated that they sold their products through middle men, who came to collect them at the sea shore; Furthermore, selling some products to tourists, which normally fetches higher prices was not considered. The results of this study must be considered in the light of these assumptions. 6. Results 6.1. Identification of Local Uses of Mangroves Based on the household survey analysis, importance of U Minh Ha mangrove forest to the local people stems from the many products taken directly as well as the indirect benefits associated with the ecosystem. The table 2 contains a summary of the benefits identified, in which the results were grouped according to; (i) direct consumptive uses (ii) direct non-consumptive uses and (iii) indirect uses. The respondents indicated their reliance on the ecosystem for wood, fish/shellfish and other products. The mangrove ecosystem also provides opportunities for tourism and recreation, education and scientific research in addition to indirect benefits as shown in the table. Table 2: Uses of U Minh Ha mangrove ecosystem Direct Consumptive Use Direct Non- Consumptive Use Wood Fish/shellfish Other Products Products Firewood Fish Honey Tourism and Water recreation Purification Charcoal Crabs Medicinal Education and Control floods plant research Fishing gear Prawns Spawning sites Construction Reduce poles erosion of coastline Cultural importance Source: Author’s calculation 453
8. 6.2. Quantification of Local Direct Uses The study revealed how much the villagers rely on the ecosystem for their livelihoods. Use of mangrove wood products within their households for either fuel wood or other purposes was evident, and on the other hand most respondents were fishermen who depend on functions of mangroves as breeding and spawning grounds for fish and other marine animal species. Table 3 gives an overview of annual per capita extraction rates of the different products collected from the ecosystem. Among the wood products, firewood and charcoal was most utilized with average annual per capita extraction rates of 317kg and 91kg respectively. Wood for making fishing gears and for house construction is as well harvested but at lower rates. Based on analysis performed for fish/shellfish products, majority of the respondents reported that fish extraction was the major use recording an annual per capita extraction rate of 82kg. In addition, the ecosystem is used for collection of crabs and prawns. Production of honey and extraction of medicinal plants from the ecosystem was also observed though the products are utilized at very low quantities. Table 3. Summary of annual per capita extraction rates for various mangrove products collected at U Minh Ha in 2018 Annual per Capita Extraction of Mangrove Products (kg) Study Fish/shellfish Wood products Others sites Villages products Fishi Construct Medici Firewo Charc Fis Cra Praw Hon ng ion nal od oal h bs ns ey gear poles Plant Khánh 356 121 53 15 45 8 2 0,6 1,3 Lâm Khánh An 64 76 55 22 70 6 2 0,5 3,1 Khánh 237 103 91 8 79 8 3 0,7 0,0 Bình Tây Bắc Trần Hợi 174 71 17 77 69 8 6 3.0 0,0 Average 208 93 54 31 66 7,5 3,3 1,2 1,1 annual/ca pita extraction (kg) Source: Author’s calculation Further revealed from the analysis is that wood products are in total harvested at an annual per capita rate of 493kg. Fish/shellfish and other products on the other hand are utilized at average rates of 92kg and 2kg respectively. Khánh Bình Tây Bắc exhibited the highest annual per capita extraction rate for wood products in which firewood contributed 454
9. the highest proportion. Fish contributed the highest proportion of the total quantity extracted annually by each person in all villages. 6.3. Local Direct Use Value Estimation of annual net benefits derived from U Minh Ha mangrove ecosystem were based on utilization of firewood, charcoal, fishing gear and construction pole (wood products); fish, crabs and prawns (fish/shellfish) as well as honey collection (other). Further, the annual direct use value was derived from sample population of 1,219 persons represented in the 101 households surveyed. Table 4: Summary of annual per capita net benefits derived from various mangrove products collected at U Minh Ha mangrove Ecosystem Annual net benefit/person (US$) Total Total annual/ annual Study Fish/shellfish Villages capita Wood products Others net sites products net benefit benefit (US$) (US$) Constructi Medic Firew Charc Fishing Fis Cra Praw Hon on inal ood oal gear h bs ns ey poles Plant Khánh 42 4 3 2 26 27 2 1 106 20996 Lâm Khánh 7 3 3 3 77 21 4 1 118 29941 An Khánh 28 3 5 1 44 25 7 1 112 29652 Bình Tây Bắc Trần 20 2 1 10 69 27 8 12 137 21400 Hợi Averag 41 3 2 5 90 22 6 3 172 209777 e annual/ capita extracti on (kg) Source: Author’s calculation As indicated in the Table, the ecosystem is valued at 209,777 US$ per year or 120 US$/ha. On average, the local people earn 172 US$ per person per year from the mangrove ecosystem, with fish contributing the highest annual income of 90 US$ per person. Firewood and use of crabs earn 41 US$ and 22 US$ per person per year respectively. 6.4. Impacts of Local Uses on the Ecosystem 455
10. The most important threat to U Minh Ha mangrove ecosystem was cited as uncontrolled exploitation of wood products. Based on analysis done to determine villagers opinion on utilization of the ecosystem, 73 out of 170 responses reported over extraction of wood products where 57 responses cited over fishing as a threat to the ecosystem. A further 40 answers stated lack of information on how the ecosystem was being exploited. The local people expressed different opinions concerning depletion of the ecosystem. Majority of the villagers, 81 out of 288 responses according to survey results felt that over-exploitation of forest vegetation, which was cited as the most important threat might lead to further reduction on food resources, in terms of reduced fish, prawn and crab catches. Lack of fuel wood and other wood products especially materials for house construction was the other major concern for the villagers. Sixty-eight responses revealed that, depletion of the ecosystem might lead to scarcity of construction material. This was followed by another 59 who believed that, young people especially those working as tour guides or assisting researchers could lose their jobs, mentioning that if the ecosystem was depleted, the number of tourists and researchers visiting the ecosystem would as a result reduce. A small number of 29, raised fears of losing human life incase of floods. Likewise, not many villagers were worried about loss of resources for future generation, with only 12 responses stating that depletion of the ecosystem could deprive the young generation a chance of benefiting from the ecosystem. Sixty-four out of 180 responses agreed that the ecosystem is of importance to them and should therefore contribute in its management and conservation. Fifty felt that, educating the community on environmental issues would help them change their perception on utilization of natural resources. Additional 46 argued that if government provided employment for the youth, their dependence on the ecosystem for their livelihood would decrease, thus reducing amount of products collected. A small number (19) of the community advocated for the government to enhance protection and management measures, while only 1 believed alternative uses of fuel wood would manage the current problem of over exploitation. 7. Discussion This study shows that, U Minh Ha mangrove ecosystem provides both direct and indirect values to the local people. Among the direct uses are; harvesting of firewood, charcoal production, wood for making fishing gears and for house construction. In addition, the ecosystem is exploited for marine organisms; fish, crabs and prawns as well as for honey production and extraction of medicinal plants. Although production of dyes and tannin from the mangrove ecosystem has been documented, no such data was 456
11. reported in the present study. Indirect benefits provided by the ecosystem include serving as feeding and spawning habitats for fish and other marine species, purification of groundwater system, protection of the coastline from erosion and control of floods. The ecosystem also provides opportunities for education, scientific research, recreation and tourism. Culturally it is important to the local people as some old folks admitted that they offer sacrifices in certain sacred parts of the forest to appease their gods. The high annual per capita extraction rates for firewood and fish is because the products are collected in huge quantities and are mainly for sale at the nearest shopping center. Charcoal production was however extracted at low rates in the village and this is mainly because the village is located far from the forest, coupled with the long process of charcoal production, many local people do not want to venture into the process as it would be uneconomical. Most local people use traditional ways of fishing as they do not have access to modern methods since the village is located far from trading centers. A person depending entirely on the ecosystem for his livelihood would earn 172 US$ per year. Considering an average per capita monthly income of 21-43 US$ earned by most local people an individual would earn 252- 516 US$ per year. Income accrued from the mangrove ecosystem is therefore important to the community as it contributes an average of 51% total annual per capita income. Assuming the local people derive annual net benefits of 51 US$ per person and an estimate 18,000 persons depend on the ecosystem, the ecosystem will be valued at 918,000 US$ per year for wood products or 526 US$/ha/year. Value for fish products considering an annual per capita net benefit of 118 US$ is estimated at 2,124,000 US$ per year or 1,216 US$/ha/year. Besides, the ecosystem is valued at 54,000 US$/year or 31 US$/ha/year for honey production. If half of the population (11,500) depend on the ecosystem for their livelihoods, the ecosystem will be valued at 586,500 US$ per year or 336 US$/ha/year for wood products, 1,357,000 US$ per year or 777 US$/ha/year for fish/shellfish and 34,500 US$ per year or 20 US$/ha/year for honey production. These community members are aware of values and threats of the ecosystem. Many were concerned that, problem of over utilization of forest resources might persist, given that the increasing population is exerting more pressure to forest wood products in terms of fuel wood consumption, which form the main energy source for domestic use in nearly all rural homes. Besides, the locals argued that lack of jobs for the youth also contribute to the problem as most villagers, the majority of whom are young people, have been for many years harvesting products for sale. Regarding human problems arising as a result of depletion of the mangrove ecosystem, low response on fears for loss of human life due to floods was because the area is not prone to floods and very few people if not anyone has experienced such a calamity in the region. Similarly, few people were worried about loss of resources for future generation, and this can be attributed to limited environmental education and 457
12. awareness in the community. The community agrees that the ecosystem is of great importance to them and should therefore participate in its management and conservation. Most of those who believed that the community should take part in conservation argued that there has been a reduction in fish catches over the years while others felt they were spending more time in search of good poles for house construction and fuel wood. It is this concern that led some locals get involved in conservation activities which include replanting of mangrove trees. There is need for an integrated management plan, which incorporates protection of the mangrove ecosystem, commercial and local use interests. To address conflicts between the different interests, government and Non-Governmental Organizations and the community need to work together to enhance conservation and sustainable utilization of the ecosystem. This can be achieved through (1) Training the local communities on sustainable exploitation of the mangrove ecosystem (2) Promoting small-scale enterprises based on mangrove uses for example beekeeping and crab culture (3) Initiation of mangrove re-forestation projects in all villages surrounding the mangrove ecosystem. A complete inventory for all uses of the ecosystem is required in order to enhance understanding on its true economic, social, cultural and ecological values. 8. Conclusion This study provides partial information on direct use value of the mangrove ecosystem, in addition, no nonmarket valuations that can provide estimation of option and non-use values have been conducted at the ecosystem.U Minh Ha mangrove ecosystem is threatened to complete disappearance in the next decades, if current extraction rate of wood products remains uncontrolled. This suggests that the mangrove ecosystem is important as it contributes an average of 51% to total annual per capita income for the local people. The local community is aware of current threats to the mangrove ecosystem and is concerned about losing income generated from the ecosystem once it is depleted. This may provide some incentives for them to protect and protest against any encroachment of the mangrove ecosystem by coastal developments. Under the current management of the ecosystem, wood products in terms of firewood, charcoal, construction poles and fishing gears are poached by local residents for sale. Given the difficulties in limiting access to the mangrove ecosystem, it is unlikely that poach of wood products can be prevented. LITERATURE CITED 1. Aizpuru, M., Achard, F. and Blasco, F. (2000), Global Assessment of Cover Change of 458
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