ENVIRONMENTAL RISK ANALYSIS IN MAGROVE AND CRAB CONSERVATION AREAS IN PAMUSIAN VILLAGE DUE TO LAND USE CHANGE IN TARAKAN CITY

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INTRODUCTION
Mangroves are one of the largest coastal ecosystems in Indonesia that provide ecosystem functions and services for terrestrial biota, sea, seagrass ecosystems -coral reefs, and surrounding areas. Indonesia has the largest mangrove area in the world with an area of 22.6%, so that Indonesian mangroves contribute significantly to the absorption of carbon dioxide (CO2), one of the greenhouse gases. So that Indonesia's mangroves play an important role in regulating global climate change. The area of mangrove forests in Indonesia has declined sharply over the past two decades. The main drivers of mangrove degradation are use for settlement and cultivation. Currently, sustainable management is needed to maintain and improve the area and quality of mangroves.
Mangrove ecosystems have ecological, physical, and socio-economic functions that are important to be developed, especially in coastal areas. According to Pramudji (Kordi, 2001), mangroves are transitional ecosystems between land and sea and are strongly influenced by waves, coastal topography, tides and especially salinity. In addition, the decomposition process that occurs in mangrove litter can support the life of creatures in it.
Mangrove forests are very important ecosystems for the conservation of fish resources. Mangroves are the habitat of fish, shrimp, crabs, and others. The ecological or biological function of mangrove ecosystems includes spawning grounds, foraging and breeding grounds for animals, especially fish, crabs and shrimp which are excellent commodities that benefit fishermen. Physically, mangrove forests prevent coastal abrasion, resist seawater intrusion and windbreaks, and reduce greenhouse gas emissions such as CO, CO2, SOx and NOx in the air and pollutants in coastal waters (Noor et al., 2006). The main factors of mangrove destruction are (1) pollution, (2) conversion of mangrove forests without considering environmental factors, and (3) excessive deforestation.
The mangrove area in Tarakan City which is part of the city's RTH is divided into two areas, namely: 1. Mangrove and Proboscis Conservation Area in Karang Rejo Village 2. Mangrove Forest Area of AL Port Mamburungan. The plan to develop mangrove areas as RTH includes: 1. Crab Mangrove Conservation Area in Pamusian Village 2. Mangrove area in West Tarakan District, 3. Mangrove area in Central Tarakan District, 4. Mangrove area in East Tarakan, and 5. Mangrove area in North Tarakan District. Over time, there was encroachment by the community, precisely in the magrove forest area in Pamusian village. This has happened since early 2021 when there were some indigenous groups, who recognized that the land belonged to them. The Tarakan City Government did not remain silent through the village piohak, Satpol PP and the Environmental Office conducted field data collection and it was produced that there were several people who had occupied and cut down mangrove trees, which were planned to be used as residential areas.

METHOD
The data used in this study is the administrative map of Pamuisan Village, Central Tarakan District, taken from the RTRW document. Implementation of Data Collection Research Data collection is divided into two types of data, namely in the form of primary data and secondary data. Primary data is obtained from direct checks in the field. Secondary data are obtained from relevant agencies or supporting literature.
In general, there are three important information to perform HEA calculations, namely: 1. Information related to the subject to be counted, namely ecosystems or natural resources that have been damaged. 2. Initial damage 3. Possible exosystem recovery rate These three pieces of information form an integral part of the HEA calculation and will determine the final result, namely the scale of restoration needed to compensate for the damage to the ecosystem that occurs. Therefore, like the percentage of maintenance relative to the baseline (% hectare or % ton), a single matrix makes it easy to calculate the damage and recovery required. Dunford et al (2004) state that when using matrices, attention should be paid to: 1. Relationship with resource wealth or important natural resource functions in habitat 2. Relationships between degraded habitats and more general habitats such as forests, wetlands, and sediments 3. Can be measured or estimated relative to the baseline 4. Comparable (measured) with metrics for restored habitat In terms of scaling, the concept essentially seeks the modulus of the number of units that must be recovered to ensure that the discounted present value of the recovery gain is equal to or equal to the discounted present value of the intermediate damage. There are two types of scale approaches in the field of environmental damage assessment: the assessment approach and the service-to-service approach. HEA uses both. This is because the resulting scaling factor represents a service that can be recovered to compensate for lost services.
Mathematically it can be interpreted with a simple equation, namely: Information: Lt = major damage Rt = major repair r = discount rate t = time P = first year started t1 = end of breakdown s1 = end of repair bats

RESULTS AND ANAYSIS
a. Conditions of the practice area Map of spatial pattern of Pamusian Village as shown below: Based on data in Regional Regulation No. 3 of 2021 concerning the RTRW of Tarakan City for 2021-2041, that Pamuisan Village has a mangrove and crab conservation area covering an area of approximately 25 hectares. After juxtaposing the 2014 image map with the 2022 image map, which can be seen in the following image:

imagery map image 2021 image
After looking at the 2021 aerial imagery map, there was encroachment of the area, namely: There is logging and illegal dwellings at the location after an inventory and measurement of approximately 5 hectares of land that has been taken and used by the community which can be seen in the photo documentation below: b. Data analysis with HEA Calculation for environmental sustainability Based on the results of field reviews and interviews with crab hunters, the following results were obtained: 1. There was damage to the mangrove area with a damaged area of 5 hectares. Calculation of losses (discharge) for the initial year of the 2021 baseline and the final year of losses in 2052 assuming natural restoration of mangrove forests for 30 years. The base year of the discount factor is 2023 assumed to be 1, the degree of loss is 20% of the total area area, and the decline of this service until 2023 and until no more losses are assumed in 2052. Discount rates are assumed to be 3%, 5% and 7% per annum. 2. According to crab seekers by ngambo / install crab traps in 1 week 3 pairs of bubu approximately 50 pieces, with catches of 3 to 5 Kg. So that in one week approximately 12 kilograms.

Analysis of the calculation of the area of damage to magrove
Based on the data obtained and carried out the calculation of HEA below:

Analysis of crab production calculations
The calculation of HEA on the impact of crab production with the results of interview data with crab hunters is: