Economic Valuation as an Instrument to Determine The Management Strategy of Baros Mangrove Forest, Bantul, Yogyakarta, Indonesia

The Baros mangrove forest in Bantul Regency is now beginning to develop. Many government and private sectors programs are rolled out to support its development. The development of the Baros mangrove forest must be in accordance with the rules of conservation so that it will not damage the mangrove ecosystem. Mangrove forest has high economical and ecological value but is very vulnerable if lack of wisdom in maintaining, preserving and managing them. The involvement of government and other stakeholders are essential in determining management policies. Unawareness of society and the government to the importance of mangrove ecosystem can cause development of it becomes uncontrolled, consequently can destroy it. Mangrove forests are an important natural resource in coastal environments, and have three main functions: physical, biological, and economic functions. To quantify the functions of mangrove forests as the basis to determine the policy is required a research instrument called economic valuation. The approach of this study is the literature review from various studies before to perceive the influence of economic valuation in determining the management strategy of Baros mangrove forest in Bantul Regency, Yogyakarta, Indonesia.


Introduction
Mangrove is one of the rare ecosystems, because the area is only 2% of the earth's surface. Indonesia is the largest mangrove ecosystem in the world [1]. Mangroves as an ecosystem have unique properties and forms and have diverse functions and benefits for humans and other living things [2].
The large potential of mangrove forests encourages excessive resource exploitation that can threaten its sustainability. Pramudji mentions that mangrove damage is not only caused by natural processes, but also due to human activities [3]. The existence of mangrove forest exploitation for the fulfilment of excessive human needs and ignoring the rules of conservation will be able to damage the mangrove itself. The ignorance of the community and the government of the importance of mangrove forest ecosystem causes development in the framework of mangrove forest area development becomes uncontrolled so that it will become damaged [4].
The existence of mangrove forest spread in Indonesia, one of them is in Baros Hamlet, Village of Tirtohargo,Kretek sub district, Bantul Regency. The mangrove ecosystem is precisely in the estuary / encounter between the southern sea and the mouth of the Opak River. The Baros mangrove forest is a mangrove conservation area that has the appeal of biological natural resources, geological formations, and / or natural phenomena that can be developed for the benefit of the development of science, research, education and awareness raising of the conservation of biological natural resources, marine tourism and recreation. Baros mangrove forest became one of the coastal and marine ecosystems that are potential for improving the welfare of the people of Baros Hamlet in terms of economic, social and environmental.
Based on interviews with the manager that the current Baros mangrove conditions as a special interest attraction has grown. The existence of programs from the government both central and regional as well as the private sector in order to develop the Baros mangrove area would need new spaces. Programs Development of mangrove areas without regard to ecological function will actually damage the existence of mangrove and this will cause problems in the future. [5] mentions that the destruction of mangrove forest one of them caused by the mistake of government policy.
Mangrove forests have high economic and ecological value but are very vulnerable to damage if not prudent in maintaining, preserving and managing them [6]. The damage usually experienced by mangrove is caused by human activities directly in the utilization of mangrove forest ecosystem. To avoid these problems, it is necessary to assess the utilization of mangrove forests, not only economic benefits but also the consideration of ecological benefits that can become a reference in the mangrove forest management strategy.
This study aims to determine the total economic value of mangrove forests and the implementation of sustainable mangrove management strategies in the mangrove area of Baros, Tirtohargo, Kretek, Bantul.

Data collection technique
This research is done by using data collection method which divided into secondary data and literature review. Secondary data were collected through document review and documentation of activities related to Baros mangrove forests. While the literature review comes from similar studies and research related to Baros mangrove forest. The analytical methods used are quantitative and qualitative methods, which are then described to explain the total economic value and strategy of Baros mangrove forest management.

Analysis technique
The economic assessment of all the benefits of natural resources of mangrove forest refers to the concept of natural or environmental value according to [7] [8]. The economic values contained in a natural resource, both useful and functional, must be taken into account in formulating management policies so that their allocations and alternative uses can be properly determined and targeted [9]. The formulation is as follows:

Results and discussion
This research was conducted in Baros mangrove forest area, Tirtohargo village, Kretek subdistrict, Bantul district located at 110 ° 17 '9199 "BT and 8 ° 0' 48.066" LS. The location of this study was chosen because it is the only mangrove forest in Bantul district and is one of the icons of tourism and conservation. The location of the research can be seen in Figure 1.

Mangrove forest ecosystem condition
The mangrove forest ecosystem in Baros Village is managed by Pemuda Pemudi Baros Family (KP2B) since 2003. Mangrove planting is done in Sultan Ground land in Opak River estuary of 25 Ha. Until now the wellgrown Mangrove is 3 -4 Ha. The type includes Avicennia sp. 60%, Rhizhopora sp. 20%, Brugueira sp.10%, and Nipah 10% [10]. Composition of mangrove species in Baros mangrove forest can be seen in Figure  2. Based on inventory conducted by [11] in Baros mangrove area recorded four (4) mangrove species: Avicennia sp., Rhizophora sp., Bruguiera sp., And Nypa frutican.  Making mangrove seedlings ready for planting (Avicenia) is able to create jobs for group members. Currently, the types of mangrove seeds made by KP2B are sold to those in need. [10] states that the mangrove seedlings per year reaches 5,200 Avicenia sp mangrove seedlings sold at Rp 2.000,00 / seedlings, the total value of Avicenia sp mangrove seedlings is Rp 10.400.000, -/ year.

Indirect use value
Coastal Protection (Breakwater) Mangrove is one of the unique and unique ecosystems that can protect the coast from abrasion [14]. The indirect benefits of mangrove forests as abrasion holder are diminized through replacement cost with the construction of breakwater buildings. Based on the research [6] The cost of breakwater construction for a distance of 1 m with endurance for 10 years is Rp. 21.986.700, -and the length of Baros mangrove forest is 500 m, the function value is Rp 10,993,350,000, -/ 10 years or Rp 1,099,335,000 / year.

Option value
The benefit of choice is a value that indicates a person's willingness to pay in order to preserve the mangrove ecosystem for future use. This value is approached with reference to the biodiversity value of mangrove forests in Indonesia.

Assessment of economic benefits of total mangrove forest
The total economic value of the mangrove ecosystem is the sum of the value of direct benefits, indirect benefits, and benefits of choice. Quantification of the benefits of mangrove forests as a whole shows that, the total benefit value of Rp.