Classification, accuracy assessment, mangrove mapping and change detection

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3.2. Classification, accuracy assessment, mangrove mapping and change detection

Supervised classification with a maximum likelihood algorithm available in ERMapper 5.5 was used in this study, because this classification algorithm produces consistently good results for most habitat types Donoghue and Mironnet, 2002. The training polygons were digitized on-screen based on terrain knowledge acquired during fieldwork and was distributed throughout the study areas. The pixels in the polygons that were selected as representatives of each class were plotted in spectral space and a visual check was made that all classes could be separated in at least one combination of bands, for ellipses containing 95 of the class pixels. To increase the size of the sample to be used in classification accuracy assessment, the layer with the field-checked sites was overlaid on the corrected satellite images, and homogeneous polygons with similar spectral reflectance, when viewed in several band combinations, were drawn around those sites. The layer of polygons created using this process was later used for checking the accuracy of the classified map. Accuracy assessment for the coastal habitat maps from the Segara Anakan ecosystem was based on 37-ground truthing points recorded during the field survey May 2004 – February 2005. Using ecological information in a Geographic Information System GIS, one can formulate and apply location and topological the relation between area- based objects rules to the classified satellite data to improve the mapping accuracy Long and Skewes, 1996 . After accuracy assessment, the classified images were exported to GIS facilities to generate the mangrove thematic map. Analysis and quantification of mangrove conversion between the different dates was included in the GIS database. Once both maps had exactly the same number of feature pixels they were subject to a cross-tabular comparison. This indicates the differences in extent of each class and the transitions that had taken place between the two dates. The characterization of land cover change is done using aggregated measurements of area by cover type at both dates and quantifying transitions. The change analysis is limited to these measurements due to the different generalization levels and minimum size of mapped units for the data sources available for the study 1978 – 2003. Results and Discussion Since 1978, the Segara Anakan region has changed enormously. A large part 42.1 of the mangrove changed into rice fields, and minor parts into other land use area such as aquaculture 2.5, dry land agriculture 5.4, urban settlement 1.1, industry 0.4 and other land cover types 1.7, see Table 2.. This was mainly caused by the high sedimentation in mangrove and water arealagoon. The sedimentation rate in the areas of mangrove and water arealagoon was estimated to be on the order of 1-3 million tonsyear Purba, 1991. Sedimentation has been one of the main management concerns in the river basin, particularly regarding the impacts on the low land activities, including the Segara Anakan. Sedimentation has been attributed to deforestation and poor agricultural management practices in the upland areas of the Citanduy river basin, as well as the 1982 volcanic eruption of Mount Galunggung, which is located in the river basin. In the western region Karanganyar, Klaces and Motean mangrove change were higher due to stronger logging and sedimentation compared to the eastern area. These changes were mainly caused by extent of urban settlements, rice fields and industry area. The largest patch of the mangrove area was converted into the rice fields that are mostly located in the northern, northwestern and northeastern part of the lagoon Figure 2. This is where most of the low 15 lying area with a great abundance of fresh water resources of the former mangrove area occurred compared to the other parts of the mangrove. a b c d Legend: Figure 2. Temporal and spatial conversion of mangrove forest of Segara Anakan since 1978 a; 1987 b; 1995 c and 2003 d. The largest proportion 42.1 of the mangrove area of the year 1978 has changed into rice fields and the smallest proportion 0.4 into industrial area about 79.7 ha. There are also important additions of the new mangroves 3,433.7 ha derived from other land cover areas such as mud flats and the open lagoon. The reduction in the addition of the new mangroves from 193.5 to 97.1 ha per year may also be the result of the progressive decrease of its original area and of the dredging activities since 1996. 16 Table 2. Temporal change in land cover area in ha in Segara Anakan. Land cover 1978 1987 Annual change 1978-1987 1995 Annual change 1987- 1995 2003 Annual change 1995-2003 Mangrove 17,090.0 15,827.6 -0.8 10,974.6 -3.4 9,597.0 -1.4 Rice fields 1,708.1 - 6,940.8 34.0 8,644.4 2.7 Aquaculture 0 127.8 - 278.3 13.1 515.1 9.5 Industry 0 46.7 - 46.8 0.0 79.7 7.8 Urban settlement 0 156.1 - 179.8 1.7 225.0 2.8 Dry land agriculture 0 678.8 - 986.6 5.0 1,108.8 1.4 Others 0 286.1 - 340.3 2.1 353.7 0.4 Total area 17,090.0 18,831.2 19,747.2 20,523.7 Table 3. Temporal trajectory of mangrove conversion in Segara Anakan. Land cover 1987 ha Annual change 1978-1987 ha 1995 ha Annual change 1987- 1995 ha 2003 ha Annual change 1995- 2003 ha Mangrove no changed 14,086.5 - 10,058.6 - 8,820.5 - New mangrove areas 1,741.1 193.5 916.0 114.5 776.5 97.1 Mangrove, converted 3,003.6 333.7 5,769.0 721.1 2,154.1 269.3 Rice fields 1,708.1 189.8 5,232.7 654.1 1,703.6 213.0 Aquaculture 127.8 14.2 150.5 18.8 236.8 29.6 Industry 46.7 5.2 0.1 0.0 32.9 4.1 Urban settlement 156.1 17.3 23.7 3.0 45.2 5.7 Dry land agriculture 678.8 75.4 307.8 38.5 122.2 15.3 Others 286.1 31.8 54.2 6.8 13.4 1.7 Remark: • Mangrove no changed: this refers to the area that remained covered by mangroves over the reference time • New mangrove: this refers to mainly former lagoon area of mud flats that due to siltation got habitable for mangroves • Mangrove converted: former mangrove area, which was converted into a different land use types. Figure 3 shows a decrease of the total mangrove area where goes opposite to the increase of the agricultural area. While mangroves covered about 17,090 ha in 1978 and rice fields was not existent at that time, both mangroves and rice fields covered about the same area in 2003 ca 9,000 ha. The increase of other land uses such as aquaculture, industry, urban settlement, dry land agriculture and others did not significantly change the extent of the converted mangroves area because of new mangrove area were building up. During the period of 1995 to 2003 for example the mangrove area converted into land use excluding rice fields was 450.5 ha, while at the same time new mangrove area of about 776.5 ha. The transformation of land use activities has been accelerated by the immigration of farmers, which has significantly increased the population of the area. The rate of the population growth at the Segara Anakan is about 2.4 per year. In general, the rate of mangrove conversion declined from the period 1987 – 1995 to 1995 – 2003, from a rate of 17 -3.4 per year to only -1.4 per year. It can be assumed that this decline resulted at least in part from the projects CRMP and SACDP conducted in Segara Anakan, as mentioned above. Figure 3. Extent of change from 1978 to 2003 by land use types. The land cover and land use changes described, particularly the great reduction of the original mangrove forest have changed the ecosystems of and around the Segara Anakan lagoon significantly. It should be asked if these changes considered to the ecosystem and to the local resource users and other stakeholders of if these changes may also provide new opportunity and benefits. The result of these changes has been an increase in the diversity and complexity of the social, economic, and environment. The local economy of the three fishing communities located in the estuary has been highly dependent on the estuary fisheries. Others land use activities around the farmers’ homes are generally more diverse than in the fishing communities, including home gardens and fishponds. Home garden crops, or palawija , are mainly located on built up areas. Small non-intensive fishponds have been constructed around some of the houses. Economic opportunities arose from rice fields development, mainly from the greater number of income generating activities, including farm labour, harvester, garden and dry land crops, and fishponds. While rice has been the dominant agricultural activity in Segara Anakan, the cultivation of other agriculture products, generally cash crops, occurs on a much smaller scale. These crops include soybean, sugar production, sorghum, fruit and vegetables, and are often sold to supplement the household income. The cultivation of the rice fields is managed through various labour arrangements, notably, farmers working the land themselves, hiring labour, andor help from family members. While producing economic benefits, aquaculture development has also been associated with environmental degradation on Segara Anakan, including the conversion of 4000 8000 12000 16000 20000 1978 1987 1995 2003 area ha total mangrov e ric e f ields 200 400 600 800 1000 1200 1978 1987 1995 2003 area h a aquaculture indus try urban s ettlem ent dry land agriculture others 18 mangroves and pollution of the surrounding waters. Mangrove conversion may lead to several problems such as reduced catch yields of commercially important species; reduced biodiversity; loss of habitats and nursery areas; coastal erosion; loss in productivity; acidification; pollution; and alteration of water drainage patterns. High population pressure in the coastal areas near Segara Anakan and elsewhere in Java has led to the conversion of many mangrove areas to other uses, including infrastructure, aquaculture and rice growing etc. The loss of biodiversity in mangrove-converted area in Segara Anakan has been reported since 1980s Sastranegara et al., 2003. Monthly fluctuation of intertidal crab diversity was more constant in the undisturbed area with a high mangrove coverage 90 compared to the crab hunting, the logging and the prawn pond area with mangrove coverage of 89, 33 and 0, respectively. Sjöling et al. 2005 reported that the nutrient and bacteria diversity are significantly different lower in the deforested mangrove areas. Issues of sustainable development of the land usecover changes were addressed in terms of economic viability, social equity and ecological integrity. Overall, the current changes have produced both constraints and opportunities for sustainable development. This paper provides information on land usecover change for resources sustainable development, that would be related with the further papers about the assessment of the Segara Anakan natural resources stocks and uses by using the models Ecopath and Ecosim. Conclusions The results of this study show that there have been important mangrove conversions in Segara Anakan from 1978 to 2003 with the largest portion of mangroves converted into rice fields 8,644.4 ha or 42.1 followed by 5.4 to dry land agriculture about 1,108.8 ha, 2.5 to aquaculture about 515.1 ha, 1.7 to other land uses about 353.7 ha, 1.1 to urban settlement about 225 ha and 0.4 to industry area about 79.9 ha. The mangrove area has continually decreased by 1.4 per year since the last decade. This process may lead to several negative impacts such as reduced fish catch, reduced biodiversity, loss of productivity and habitat as a spawning, nursery and feeding ground. Rapid human population growth and sedimentation are the most important causes of the mangrove conversions in the study area. Acknowledgements The authors want to thank the SPICE project, Center for Tropical Marine Ecology ZMT Bremen, Deutscher Akademischer Austauschdienst DAAD, German Ministry of Education and Research BMBF and University of Jenderal Soedirman, Purwokerto, for their support during this study; Biotrop Training and Information Center BTIC Bogor for images support. References Adeel, Z., Pomeroy, R., 2002. Assessment and management of mangrove ecosystems in developing countries. Trees 16, 235-238. 19 Alongi, D.M., Pfitzner, J., Trott, L.A., Tirendi, F., Dixon, P., Klumpp, D.W., 2005. Rapid sediment accumulation and microbial mineralization in forests of the mangrove Kandelia candel in the Jiulongjiang Estuary, China. Estuarine, Coastal and Shelf Science 63, 605-618 Ardli, E.R., Widyastuti, A., 2001. Application of NDVI analysis from Landsat TM and SPOT images for monitoring and detection of mangrove damages at Segara Anakan Cilacap, Central Java. in Bahasa Indonesia. DUE-like Project Unsoed, Purwokerto. Blasco, F., Saenger, P., Janodet, E., 1996. Mangroves as indicators of coastal change. Catena 27, 167-178. BPKSA Badan Pengelola Kawasan Segara Anakan, 2003. Laporan pelaksanaan proyek konservasi dan pembangunan Segara Anakan. Lokakarya Status, Problem dan Potensi Sumberdaya Perairan dengan Acuan Segara Anakan dan DAS Serayu. Purwokerto. Donoghue, D.N.M., Mironnet, N., 2002. Development of an integrated geographical information system prototype for coastal habitat monitoring. Computer Geosciences 28, 129-141. Dudley, R.G, 2000. Segara Anakan Fisheries Management Plan. Segara Anakan Conservation and Development Project. Component BC. Consultant’s Report. FAO, 2003. State of the world forest. FAO, Rome. Filho, P.W.S., Paradella, W.R., 2002. Recognition of the main geobotanical features along the Bragança mangrove coast Brazilian Amazon Region from Landsat TM and RADARSAT-1 data. Wetlands Ecology and Management 10,123-132. Long, B.G., Skewes, T.D., 1996. A technique for mapping mangrove with Landsat TM satellite data and geographic information system. Estuarine, Coastal and Shelf Sciences 43, 373-381. Manson, F.J., Loneragan, N.R., Harch, B.D., Skilleter, G.A., Williams, L., 2005. A broad- scale analysis of links between coastal fisheries production and mangrove extent: A case-study for northeastern Australia. Fisheries Research 741-3, 69-8. Mumby, P.J., Skirving, W., Strong, A.E., Hardy, J.T., LeDrew, E.F., Hochberg, E.J., Stumpf, R.P., David, L.T., 2004. Remote sensing of coral reefs and their physical environment. Marine Pollution Bulletin 48, 219-228. Mumby, P.J., Green, E.P., Edwards, A.J., Clark, C.D., 1999. The cost-effectiveness of remote sensing for tropical coastal resources assessment and management. Journal of Environmental Management 55, 157-166. Novelli Y.S., CintroÂn-Molero, G., Soares, M.L.G., De-Rosa, T., 2000. Brazilian mangroves. Aquatic Ecosystem Health and Management 3, 561-570. Primavera, J.H, 1998. Mangroves as nurseries: Shrimp populations in mangrove and non- mangrove habitats. Estuarine, Coastal and Shelf Science 46, 457–464 Purba, M. 1991. Impact of high sedimentation rates on the coastal resources of Segara Anakan, Indonesia, p. 143-152. In L.M. Chou, T.-E. Chua, H.W. Khoo, P.E. Lim, J.N. Paw, G.T. Silvestre, M.J. Valencia, A.T. White and P.K. Wong Eds. Towards an Integrated management of tropical coastal resources. ICLARM Conference Proceedings 22, 455p. National University of Singapore, Singapore; and International Center for Living Aquatic Resources Management, Philippines. Sastranegara, M.H., Fermon, H., Mühlenberg, M., 2003. Diversity and abundance of ntertidal crabs at the East Swamp Managed Area in Segara Anakan Cilacap, Central Java, Indonesia. Deutscher Tropentag, Göttingen. 20 Sjöling, S., Mohammed, S.M., Lyimo, T.J., Kyaruzi , J.J., 2005. Benthic bacterial diversity and nutrient processes in mangroves: impact of deforestation. Estuarine, Coastal and Shelf Science 63, 397–406. Soemodihardjo, S., Suroso, Suyarso, 1991. The mangroves of Segara Anakan: An assessment of their condition and prospects, p. 213-222. In L.M. Chou, T.-E. Chua, H.W. Khoo, P.E. Lim, J.N. Paw, G.T. Silvestre, M.J. Valencia, A.T. White and P.K. Wong Eds. Towards an Integrated management of tropical coastal resources. ICLARM Conference Proceedings 22, 455p. National University of Singapore, Singapore; and International Center for Living Aquatic Resources Management, Philippines. Tomascik, T., Mah, A.J., Nontji, A., Moosa, M.K. 1997. The ecology of the Indonesian seas. Part II chapter 13-23. Periplus Editions, Singapore. Vasconcelos, M.J.P., Mussa´Biai, J.C., Arau´jo, A., Diniz, M.A., 2002. Land cover change in two protected areas of Guinea-Bissau 1956–1998. Applied Geography 22, 139– 156. Weiers, S., Block, M., Wissen, M., Rossner, G., 2004. Mapping and indicator approaches for the assessment of habitats at different scales using remote sensing and GIS methods. Landscape and Urban Planning 67, 43-65. White, A.T., Christie, P., D’Agnes, H., Lowry, K., Milne, N., 2005. Designing ICM project for sustainability: Lesson from the Philippines and Indonesia. Ocean Coastal Management 48, 233-251. White, A.T., Martosubroto, P., Sadorra, M.S.M., Eds. 1989. The coastal environmental profile of Segara Anakan-Cilacap, South Java, Indonesia. ICLARM Technical Reports on Coastal Area management Series no. 25. International Centre for Living Aquatic Resources Management, Manila. Yulastoro, P., 2003. Usaha dan kendala penyelamatan degradasi lingkungan Segara Anakan. Lokakarya Status, Problem dan Potensi Sumberdaya Perairan dengan Acuan Segara Anakan dan DAS Serayu. Purwokerto. 21 ILLEGAL LOGGING OF MANGROVES IN SEGARA ANAKAN CILACAP: A CONSERVATION CONSTRAINT by Moh. Husein Sastranegara 1 , Edy Yuwono 1 , Purnama Sukardi 2 1 Faculty of Biology, University of Jenderal Soedirman, Purwokerto, Indonesia 2 Faculty of Science and Technique, University of Jenderal Soedirman, Purwokerto, Indonesia msastraweb.de Introduction In general, tropical forest areas are in Central America, Central Africa, Southeast Asia, and the islands of Pacific Oceans. The biggest forest is in Southeast Asia, especially Indonesia which has 120 millions ha in areas Haeruman, 1980. Segara Anakan Cilacap has 9,600 ha in the number of mangroves Erwin Ardli Riyanto, this volume. The role of mangroves is as the habitat of living organisms Sasekumar et al., 1992; Marshall, 1994; Ewell et al., 1998. Based on the forest map of the State Forest Corporation, mangroves in Segara Anakan Cilacap is in “Estuarine Forest Corporation Class“ Perum Perhutani, 1993. Mangrove or estuarine forests grow in protected coast, river mouth or lagoon. Their distribution and composition are not dependent upon climate, but edaphic factor soil type and tide. Structure of mangroves is simple and consists of one layer of canopy and the small number of species Bupati Cilacap, 2001b. Unfortunately, illegal logging of mangroves is still continuing and will disturb the available of mangroves in Segara Anakan Cilacap. Yuwono et al., 2007 declared that mangroves in Segara Anakan Cilacap is considered to be the largest remaining single mangrove in the south coast of Java. Therefore, the Segara Anakan Management Areas 108°46´ – 109°03´ E and 7°35´ – 7°48’ S is divided into the West Swamp-managed Areas Swamp- production Zones: 108°46´ E – 108°53´ E and 7°35´ S – 7°43’ S and the East Swamp-managed Areas Swamp-protected Zones: 108°53´ E – 108°58´ E and 7°39´ S – 7°44’ S; and Swamp- production Zones: 108°57´ E – 109°02´ E and 7°40´ S – 7°45’ S by the government of Cilacap Bupati Cilacap, 2000; GIS Lab PMO – SACDP, 2000. Mangroves in Segara Anakan Cilacap are managed by the Central Java State Forest Corporation, Forestry Department. Swamp-production zones is in the West and the East swamp-managed areas of Segara Anakan Cilacap that silvofishery leading to the complete clear-cutting of mangrove trees as in the prawn pond areas leads to a highly impoverished crab community both in terms of crab individual and diversity Sastranegara et al., 2003. In general, the mangrove destruction has marked effects on species diversity Hobbs and Huenneke, 1992. Sucgang et al ., 1994 clarified that conversion of mangrove into prawn ponds resulted in coastal erosion producing a retreating shoreline, inundated wetlands, salt water intrusion, depletion on the supply of river sediments, disastrous flooding, damages to infrastructures, loss of property, and mangrove destruction. Then, mangrove destruction makes a decreasing of species diversity. Hampicke 1994 reported that nature can be valued in its own right or as an instrument for the benefit of humankind which substantiate conservation as moral duty. This background inspires the purpose of research which is as follows: 1. to know the kind of species that is cut by local people in Segara Anakan Cilacap, 2. to calculate the average of felled tree per days in Segara Anakan Cilacap, and 3. to find the source of felling of trees in Segara Anakan Cilacap. 22 So far, the research can provide useful information on the illegal logging as mangrove constraint in Segara Anakan Cilacap for conservation suggestion efforts which is done by the Central Java State Forest Corporation, Forestry Department, the Republic of Indonesia. Methods Survey method was taken in the Segara Anakan Management Areas in the period of half way between spring and neap tidal periods every month from March 2006 to May 2006. The Segara Anakan Management Areas is divided into the West Swamp-managed Areas Swamp-production Zones: route of field trip is from station 21, Y, 24, 22, X, Y, 19, 18, 20, 17, 6, 17, 11, 17, 8, 7, 8, 7, 8, 9, 10, 20, 21 to 24; or from station Y, 19, 10, 17, 6, 17, 11, 17, 11, 17, 8, 7, 8, 9, 10, 20, 24, X, 26 to 21 and the East Swamp-managed Areas Swamp-protected Zones and Swamp-production Zones: route of field trip is from station 2, 5, 4, 3, 4, 5, 2, 1, 12, 1, 13, 14, 15, 14 to 13. The kind of species that is cut by local people in Segara Anakan Cilacap is known by identification of various parts of felled tree Ng and Sivasothi, 1999; Tomlinson, 1999. The average of felled tree per days in Segara Anakan Cilacap is known by the multiplication between the average of number of wooden ship per days and the average of number of volume of felled tree inside wooden ship. The source of felling of trees in Segara Anakan Cilacap is known by route of field trip in accordance with Science for the Protection of Indonesian Coastal Marine Ecosystems SPICE as BMBFDKPRISTEK Project in the year of 2003-2007 route from Sleko at the East Swamp-managed Areas at 09.00 a.m. to the West Swamp-managed Areas. All data is described by descriptive approach. Results and Discussion Mangroves in Java and Kalimantan islands have 29 species in number Tomlinson, 1999 and Cilacap Regency has 26 species Cilacap Regent, 2001b. Therefore, Segara Anakan Cilacap has a good diversity potential. ASEAN US CRMP 1992 was worried about illegal logging of mangroves in Segara Anakan Cilacap affecting the decreasing of aquatic organism diversity and catching effort of fishes per year. Sastranegara 2004 showed that Segara Anakan Cilacap has 16 species at the East Swamp-managed Areas. The result of research showed that Rhizophora apiculata, R. mucronata, and Bruguiera gymnorrhiza was cut by local people. R. apiculata and R. mucronata tend to use for charcoal and firewood, whereas B. gymnorrhiza is for building material needs. Various parts of felled tree were cut with an adze and machete in back mangroves at low tide. At high tide, it was transported by wooden ships. Therefore, the condition of mangrove is a good enough in front mangroves and the other way of back mangroves. The number of wooden ship bringing the various parts of felled tree is between 6 and 14 per day Table 1b with 10.17 wooden ship on average Figure 1b, and the average of number of volume of felled tree inside wooden ship is 400 cm in length x 70 cm in width x 50 cm in height = 1.4 m 3 in volume Figure 2. Therefore, the average of felled tree in Segara Anakan Cilacap is 14.23 m 3 per days. A year before at the same month, Sastranegara and Marhaeni 2005 reported that the number of wooden ship bringing the various parts of felled tree is between 5 and 8 per days Table 1a with 6.42 wooden ship in average Figure 1a, and the average of number of volume of felled tree inside wooden 23 ship is same. Therefore, the average of felled tree in Segara Anakan Cilacap is 8.98 m 3 per day. It means that there is increasing number of the average as much 158.46 percent. If the average of felled tree in Segara Anakan Cilacap which is 14.23 m 3 per days 5,122.80 m 3 per year is continue, the mangrove area will continually decreased. Table 1. The number of wooden ship bringing the various parts of felled tree on 2005 a and 2006 b. a Month March 2005 April 2005 May 2005 Date 11 12 26 27 10 11 25 26 9 10 24 25 No. wooden ship 7 6 6 6 7 6 6 8 6 5 8 6 No.stationtime of occurence 0211.50 2110.16 2110.35 1814.50 0211.55 2110.14 2110.45 2110.18 0112.56 2110.32 0109.55 2212.45 0112.15 2110.16 1813.50 1915.00 0211.55 2110.17 1812.15 1811.45 1514.07 1913.52 1311.16 2213.03 1514.18 1813.40 1914.00 1915.00 1514.42 1813.59 1812.15 1912.11 1514.11 2215.00 1311.18 2213.24 1514.18 1813.40 1914.10 2215.40 1415.59 1914.53 1914.33 1912.11 1414.27 1316.57 2113.33 2213.24 1414.44 1914.10 2215.20 2215.40 1316.30 2215.30 2215.44 2214.00 1315.03 0117.15 2113.40 1316.40 1414.50 2215.00 2215.20 1317.45 0116.45 1317.58 1318.05 1317.06 0116.55 2113.40 0217.59 1315.19 0116.45 1317.06 1814.10 0117.40 1914.19 b Month March 2006 April 2006 May 2006 Date 16 17 14 15 9 10 Wooden ship 11 9 6 12 9 14 Stationtime 1315.15 X07.03 0310.24 2206.28 0310.15 2406.30 0411.14 1907.19 0511.30 1908.12 1213.16 1808.18 0211.50 1808.45 2009.20 0113.10 2009.35 1010.35 1515.17 1011.08 1111.57 1113.17 1712.23 0613.05 Therefore, the average of felled trees per day in Segara Anakan Cilacap is faster than its growth. Then, we cannot find the big mangroves because they grow slowly. For example, mangroves in the village of Tritih Kulon, the district of Cilacap Utara, the regency of Cilacap which is established in 1980’s has only 7.5 m in height. Haeruman 1980 showed that the hole of canopy cover needs 200 years for their recovery. The source of felling of trees is at Swamp-protected Zones in the East Swamp- managed Areas of Segara Anakan Cilacap. It is known from the direction of wooden ships Figure 3. Various parts of felled tree were sold for business needs at the kampong of Kali Panas and the village of Lomanis station 2; whereas local needs at the village of Kutawaru between station 2 and 14, Motean east part of station 21, Karanganyar station 18 and Majingklak station 17. The last three stations are found at the north field trip of lagoon because the local people have always tried to avoid the guard post of marines station 20 at the district of Kampung Laut, Cilacap Regency. 24 a b 2 4 6 8 10 12 14 16 16 .03 .2 00 6 17 .0 3 .2 006 14 .0 4 .2 006 15 .04 .2 006 09 .05 .2 00 6 10 .05 .2 00 6 Date N u m b er o f w o od y sh ip p e r day A verage V alue Figure 1. The number of wooden ship in average in the year of 2005 a and 2006 b Figure 2. The average of number of volume of felled tree inside wooden ship 1 2 3 4 5 6 7 8 9 11 .0 3.2 00 5 12 .0 3. 20 05 26 .0 3. 20 05 27 .0 3. 20 05 10 .0 4. 20 05 11 .0 4. 20 05 25 .0 4. 20 05 26 .0 4. 20 05 09 .0 5. 20 05 10 .0 5. 20 05 24 .0 5. 20 05 25 .0 5. 20 05 Date N u m b e r of wo ody s h ip pe r da y Average Value 25 Figure 3. The direction of wooden ships Based on the deep interview to local people, there are smokestacks at station 2 for burning mangrove trees in relation to produce charcoals. At least, it can produce charcoal as much 12 m 3 per days which is coming from three trucks per six days. The size of truck is 6 m in length x 2 m in width x 2 m in height. It means that the charcoal is as much 12 m 3 per days for business needs and 2.23 m 3 per days for local needs. The number of 2.23 m 3 per days is calculated from the average of felled tree in Segara Anakan Cilacap as much 14.23 m 3 per days minus 12 m 3 per days. Now, Scientist and politicians agreed that biological diversity is in crisis due to human activities Van-Wright et al., 1991. Human activities in relation to mangrove have been regulated in Cilacap. For example, the illegal logging of mangroves is an infraction of roles as follows: 1. Peraturan Daerah Kabupaten Cilacap Nomor: 17 Tahun 2001 about the mangrove management in Segara Anakan Cilacap, especially article 11 Bupati Cilacap, 2001b; 2. Peraturan Daerah Kabupaten Cilacap Nomor: 6 Tahun 2001 about the art plan of Segara Anakan, Cilacap Areas, especially article 14 Bupati Cilacap, 2001a; 3. Peraturan Daerah Kabupaten Cilacap Nomor: 23 Tahun 2000 about Segara Anakan Cilacap border line, especially article 13 Bupati Cilacap, 2000. Conclusions Rhizophora apiculata , R. mucronata, and Bruguiera gymnorrhiza was cut by local people with the average of various parts of felled tree as much 14.23 m 3 per days, especially from Swamp-protected Zones in the East Swamp-managed Areas of Segara Anakan Cilacap. Various parts of felled tree were cut with an adze and machete in back mangroves at low tide. At high tide, it was transported by wooden ships. Therefore, the condition of mangrove is a good enough in front mangroves and the other way of back 26 mangroves. The kind of species R. apiculata and R. mucronata tend to use for charcoal and firewood, whereas B. gymnorrhiza is for building material needs. The illegal logging of mangroves is a constraint for conservation tasks because the diversity of aquatic organisms decreases in Segara Anakan Cilacap. Therefore, natural resource and environmental management should be done as a holistic perspective. References ASEAN US CRMP. 1992. The integrated management plan for Segara Anakan Cilacap, Central Java, Indonesia. International Centre for Living Aquatic Resources Management Tech. Rep. 34, Manila. Bupati Cilacap. 2000. Peraturan daerah kabupaten Cilacap Nomor: 23 Tahun 2000 tentang penetapan batas kawasan Segara Anakan. Pemerintah Daerah Kabupaten Cilacap, Cilacap. ____________. 2001a. Peraturan daerah kabupaten Cilacap Nomor: 6 Tahun 2001 tentang Rencana tata ruang kawasan Segara Anakan. Pemerintah Daerah Kabupaten Cilacap, Cilacap. ____________. 2001b. Peraturan daerah kabupaten Cilacap Nomor: 17 Tahun 2001 tentang Pengelolaan hutan mangrove di kawasan Segara Anakan. Pemerintah Daerah Kabupaten Cilacap, Cilacap. Ewell, K.C., Twilley, R.R., Ong, E.O., 1998, Different kinds of mangrove forests provide different goods and services. Global Ecology and Biogeography Letters 7, 83-94. GIS Lab PMO – SACDP. 2000. Land use of Segara Anakan Cilacap management areas and number of areas. GIS Lab PMO – SACDP, Cilacap. Haeruman, H., 1980. Hutan sebagai lingkungan hidup. Kantor Menteri Negara Pengawasan Pembangunan dan Lingkungan Hidup, Jakarta. Hampicke, U., 1994. Ethichs and economics of conservation. Biological Conservation 67, 219-231. Hobbs, R.J., Huenneke, L.F., 1992. Disturbance, diversity, and invasions: Implications for conservation. Conservation Biology 63, 324-337. Marshall, N., 1994. Mangrove conservation in relation to overall environmental considerations. Hydrobiologia 285, 303-309. Ng, P.K.L., Sivasothi, N. 1999. A guide to the mangroves of Singapore 1. Singapore Science Centre, Singapore. Perum Perhutani. 1993. A glance at Perum Perhutani State Forest Corporation Indonesia. Perusahaan Umum Perhutanan Indonesia, Jakarta. Sasekumar, A., Chong, V.C., Leh, M.U., Cruz, R.D., Mangroves as habitat for fish and prawns. Hydrobiologia 247, 195-207. Sastranegara, M.H. 2004. The impact of forest use on the intertidal crab community in managed mangroves of Cilacap, Central Java, Indonesia. Cuvillier, Göttingen. Sastranegara, M.H., Fermon, H., Mühlenberg, M. 2003. Diversity and abundance of intertidal crabs at the East swamp-managed areas in Segara Anakan Cilacap, Central Java, Indonesia. Proceedings of Deutcher Tropentag 2003: Technological and Institutional Innovations for Sustainable Development in Göttingen, October 8- 10, 2003. Sastranegara, M.H., Marhaeni, B. 2005. Penebangan mangrove di Segara Anakan Cilacap. Seminar Nasional Biologi dan Akuakultur Berkelanjutan dalam rangka Dies Natalis UNSOED ke-42 di Fakultas Biologi UNSOED Purwokerto, 10 September 2005. 27 Sucgang, B.L., Cabantog, A.V., Domasig, W.F., 1994. Assessment of the coastal degradation of northeastern Leyte. Ecosystems and Nat. Res. 41, 1-18. Tomlinson, P.B. 1999. The Botany of mangroves. Cambridge University Press, Cambridge. Van-Wright, R.I., Humphries, C.J., Williams, P.H., 1991. What to protect?- Systematics and the agony of choice. Biological conservation 55, 235-254. Yuwono, E., Jennerjahn, T.C., Nordhaus, I., Ardli, E.R., Sastranegara, M.H., Pribadi, R., 2007. Ecological status of Segara Anakan, Java, Indonesia, a mangrove-fringed lagoon affected by human activities. Asian Journal of Water, Environment Pollution 4, 61-70. 28 ENVIRONMENTAL CONDITIONS IN THE SEGARA ANAKAN LAGOON, JAVA, INDONESIA by Tim Jennerjahn 1 , Peter Holtermann 2 , Insa Pohlenga 1 Bushra Nasir 1 1 Center for Tropical Marine Ecology, Bremen, Germany 2 University of Rostock, Rostock, Germany tim.jennerjahnzmt-bremen.de Introduction Segara Anakan is one of the last remaining mangrovelagoon ecosystems on the Indonesian island of Java, one of the most densely populated areas in the world. For more than 400 years it has been a resource nourishing and providing income to the local population. However, the natural resources and hence socio-economic goods and services of the mangrove-fringed lagoon are endangered by degradation and pollution through unsustainable land use practices in the hinterland, overexploitation of its resources and pollution from industry and households. The lack of understanding of the ecosystem structure and functions and in consequence the lack in public awareness of the ecological value of the mangroves led to the failure of past management programmes. Mangroves do not only provide goods like, e.g. wood, or serve as nursery of many commercially important species. They are also important physical barriers providing protection to tropical coastlines, a lesson learned from the Tsunami in December 2004 the destructive effects of which would have been much less, for example, in Aceh if the mangroves had not been cut off. Segara Anakan is a mangrove-fringed shallow coastal lagoon located in south central Java which is under the influence of manifold natural and anthropogenic factors. The tropical humid climate is governed by the monsoons. Major part of the annual precipitation of 3,000-3,500 mm falls during months November to March White et al., 1989; Whitten et al., 1996. The hydrology of the lagoon is governed by seasonally varying river runoff mainly of the Citanduy River in the west and tidal exchange with the Indian Ocean. Major threats to ecosystem functions of the lagoon are high sediment and nutrient inputs by the Citanduy River, mangrove degradation, land use change and industrial and urban pollution. The mangrove area has been drastically reduced major part of which has been converted to cropland. Major land use in the area is agriculture, mainly cultivation of irrigated rice. All these are impairing natural ecosystem functions and hence living resources which to a large extent form the economic potential of the lagoon. Mangroves and tidal flats are highly important sites for the biogeochemical cycling of elements and as habitat for numerous benthic organisms Alongi, 1998. High sediment input from the Citanduy due to unsustainable land use practices in the river catchment leads to changes in the distribution of water and land-covered area, alters or destroys habitats of benthic organisms and affects benthic-pelagic coupling and carbon and nutrient cycling. The bilateral Indonesian-German research and education initiative SPICE Science for the Protection of Indonesian Coastal Marine Ecosystems is designed to address the scientific, social and economic issues related to the management of the Indonesian coastal ecosystems and their resources. A major task in this context is to study the quality and biogeochemical composition of water and its dissolved and particulate loads which provide the basis for the lagoons living natural resources. Here we report preliminary results of 29 investigations on the environmental conditions in the lagoon and its surroundings obtained during the first phase of SPICE 2003-2007. Results and Discussion Bathymetry and hydrodynamics Recent information on bathymetry and hydrodynamics of the lagoon and discharge of the Citanduy River were obtained from tide gauges and ADCP Acoustic Doppler Current Profiler measurements and modelling with the open source GETM model General Estuarine Ocean Model, www.getm.eu . The central and western parts of the lagoon are extremely shallow with water depths often 2 m. Only in the westernmost part from the Citanduy River mouth to the Indian Ocean water depths are greater with a maximum depth of 10 m in the Plawangan channel Figure 1. In the eastern lagoon water depths of 5-10 m are recorded in the Sapuregel and Donan branches because of little freshwater and sediment input. Near Cilacap port facilities and in the channel connecting the lagoon to the Indian Ocean water depth is around 10 m also because of dredging of the navigation channel. Preliminary results of short-term flux measurements indicate an average discharge of the Citanduy River of 140 m 3 s -1 range 80-300 m 3 s -1 and an average outflow to the Indian Ocean through the Plawangan channel of 555 m 3 s -1 range 0-1200 m 3 s -1 . Measurements and model calculations indicate an E-W exchange in the range of 0- 400 m 3 s -1 . Model calculations indicate a westward propagation of the tidal wave in the lagoon with a delay of about one hour in its western part. Freshwater input into the lagoon increases considerably during the rainy season, particularly in the western part. While saltwater input is low during that time the incoming flood tide is pushing the river plume towards the center of the lagoon thereby possibly enhancing sediment deposition during the rainy season. It appears that tidal dynamics are an important control of the dispersal and deposition of dissolved and particulate substances in the lagoon. Figure 1. Bathymetry of the Segara Anakan lagoon. Inset shows depth contours in the Plawangan channel, the western connection of the lagoon to the Indian Ocean. 30 Dissolved inorganic nutrients Results of dissolved inorganic nutrient analyses indicate a large spatio-temporal variability in the lagoon. Dissolved silicate was in the range of 10-230 µM between May 2004 and February 2005 while dissolved phosphate was mostly 1 µM. Dissolved inorganic nitrogen DIN ranged between 4-40 µM and displayed an W-E gradient with maximum DIN in the Citanduy River and a decrease in concentration towards the East Figure 2. Maximum concentration in the river and its eastward decrease appear to reflect the land use and hydrology pattern of the lagoons environs. More than half of the land use in the Segara Anakan region is agriculture, predominantly the cultivation of rice under irrigation and fertilizer application Yuwono et al., 2007. The observed DIN pattern indicates that major part of the nitrogen probably originated from agricultural soils and was introduced into the lagoon by the Citanduy River. However, the observed DIN concentrations i do not indicate nutrient pollution and eutrophication and ii the set of data existing as yet has a preliminary character, because it does not account for tidal variation and the spatial coverage of the lagoon is still inadequate for an overall assessment and budgeting of nutrients in the lagoon. Figure 2. Concentration of dissolved inorganic nitrogen DIN = nitrate + nitrite + ammonium in the Citanduy River and the western Area 1, central Area 2 and eastern Area 3 parts of the Segara Anakan lagoon between May 2004 and February 2005. Values displayed are regional averages not accounting for tidal variation which may be a substantial factor for the observed amplitude of changes. Ma y 0 4 Ju n 04 Ju l 0 4 Au g 04 Se p 04 Oc t 04 N ov 04 De c 04 Ja n 05 Fe b 05 DIN µ M 10 20 30 40 Ma y 0 4 Ju n 04 Jul 4 Au g 04 Se p 04 Oc t 0 4 No v 04 De c 04 Ja n 05 Fe b 05 DIN µ M 10 20 30 40 Area 1 Citanduy Ma y 04 Ju n 04 Ju l 0 4 Au g 04 Se p 04 Oct 4 No v 0 4 D ec 4 Jan 5 Fe b 05 DIN µ M 10 20 30 40 Area 2 Ma y 0 4 Ju n 04 Ju l 04 Au g 04 Se p 04 Oc t 04 No v 0 4 D ec 4 Jan 5 Fe b 05 DIN µ M 10 20 30 40 Area 3 31 Sediment and porewater biogeochemistry of mangrove cores Investigations of sediment cores and porewater from three mangrove areas in the central and eastern part of the lagoon also indicate seasonal and spatial variability in the biogeochemical composition and redox conditions. Because of less allochthonous sediment input and tidal dynamics sediments at station 16 in the eastern lagoon are coarse-grained. Sediments are fine-grained at stations 24 and 26 in the central part of the lagoon because of high sediment input from the Citanduy River. Oxygen concentrations in porewater of approx. 3-4 mg l -1 decreased with depth in cores from stations 16 and 26 while they were initially low 0.5 mg l -1 at station 24 which is more frequently inundated than the other stations. Sediments displayed little seasonal variation dry vs. rainy, but considerable spatial variation in organic carbon C org and total nitrogen N concentrations Figure 3. An initially high C org concentration at the surface of about 4 and a strong downcore decrease was observed at station 24. This may be due to high delivery of allochthonous sediment and reduced organic matter decomposition in the frequently inundated and low- oxygenated mangrove area. Less allochthonous input and high oxygen supply appear to be responsible for the initially lower C org contents at station 26 and the less pronounced decrease downcore. A strong downcore increase of C org was observed at station 26. It is probably due to high belowground root biomass of the mangrove plants and little allochthonous sediment and carbon input. 24 C org [] 2 4 6 8 10 12 dept h [ c m] 10 20 30 40 50 60 26 C org [] 2 4 6 8 10 12 dept h [ c m] 10 20 30 40 50 60 16 C org [] 2 4 6 8 10 12 dept h [ c m] 10 20 30 40 50 60 Figure 3. Concentration of organic carbon C org in mangrove sediment cores from stations 24 central lagoon, 26 central lagoon and 16 eastern lagoon. Cores were collected during the wet January, filled circles and dry August, open circles seasons of 2006. Conclusions Preliminary results of our investigations indicate a large spatio-temporal variability of hydrodynamics and the biogeochemical fluxes and composition of dissolved and particulate substances in the lagoon as well as in the fringing mangroves. It is conceivable that human activities in the Segara Anakan environs are a major control of the inputs, dispersal and deposition of dissolved and particulate substances in the lagoon. In the mangroves, benthos abundance and community composition appear to be an important additional control of carbon and nutrient cycling. 32 References Alongi, D.M., 1998. Coastal ecosystem processes. CRC Press, Boca Raton, 419 pp. White, A.T., Martosubroto, P., Sadorra, M.S.M., 1989. The coastal environmental profile of Segara Anakan - Cilacap, South Java, Indonesia. ICLARM Techn. Rep. 25, Manila, Philippines, 82 pp. Whitten, T., Soeriaatmadja, R.E., Afiff, S.A., 1996. The ecology of Java and Bali. The Ecology of Indonesia Series Vol. II, Periplus Editions, Dalhousie University, Halifax, 1028 p. Yuwono, E., Jennerjahn, T.C., Nordhaus, I., Ardli, E.R., Sastranegara, M.H., Pribadi, R., 2007. Ecological status of Segara Anakan, Java, Indonesia, a mangrove-fringed lagoon affected by human activities. Asian Journal of Water, Environment Pollution 4: 61-70. 33 THE BENTHIC COMMUNITY IN THE SEGARA ANAKAN LAGOON, JAVA, INDONESIA by Inga Nordhaus Center for Tropical marine Ecology, Bremen, Germany inga.nordhauszmt-bremen.de Introduction Benthic organisms besides fish form major part of Segara Anakans SA living resources and hence of its economic potential. The lagoon with its extensive intertidal mudflats and fringing mangroves provides nursery grounds for many species of fish, shrimps and mud crabs. The function of mangroves to serve as nursery sites, feeding grounds and protection areas for fish, invertebrates, mammals and birds is well known Robertson and Duke, 1987; Robertson and Alongi, 1992; Sasekumar et al., 1992; Krumme, 2003. Benthic organisms are also important for energy flow in ecosystems and they mediate nutrient remineralization in the sediment. Nutrient recycling in the mangrove habitat is highly promoted by litter-consuming mangrove crabs e.g. Nordhaus and Wolff, 2007. They can consume the bulk of mangrove litter which would otherwise be exported by the tides and thus help to retain nutrients in this initially nutrient-poor ecosystem Robertson and Daniel, 1989; Emmerson and Mc Gwynne, 1992; Nordhaus et al., 2006. The economic demands of a growing population at SA are continuously increasing, resulting in various human activities which strongly alter and deteriorate environmental conditions. The high sediment input by rivers due to unsustainable land use practices in the hinterland and increased erosion due to mangrove cutting are important stress factors for the benthic epifauna and may lead to a reduction of populations Yuwono et al., 2007. Additionally, dredging of the central lagoon, originally conducted to maintain open lagoon waters and improve the situation, in contrast resulted in habitat destruction. The lagoon is also affected by chemical contamination, in particular high inputs of effluents from agriculture, households and the oil refinery of Cilacap. Construction and subsequent abandonment of fish ponds has left behind areas which mostly have not been re-colonized by mangroves yet. Therefore, the capacity of the SA Lagoon as a nursery ground and thus its ecological and economic importance is constantly diminishing. Since long-term surveys on benthic populations and communities in the tropics are scarce, temporal patterns are poorly understood Alongi, 1990, but they are essential in understanding natural temporal variations of benthic populations which is a prerequisite for assessing anthropogenic impacts Essink et al., 1998; Dittmann, 2002. Data on the diversity and distribution of benthic organisms of SA are limited and seasonal patterns were not analysed. Several studies suggest that crustaceans and gastropods dominate in SA, however, the full species stock has not been explored Djohan, 1982; Hardjosoewarno et al ., 1982; Pribadi, 2003; Suryono et al., 2003; Widianingsih et al., 2003; Sastranegara, 2004. Our work within the SPICE Science for the Protection of Indonesian Coastal Marine Ecosystems programme aimed i to record the full species stock of epi- and endobenthic macrofauna, ii to determine the temporal and spatial distribution of the benthic communities in the mangrove areas, tidal flats and the shallow waters of the SA Lagoon over a two years period, and iii to investigate the population biology and feeding ecology of dominant benthic species. This work should provide baseline data in order to 34 understand how and to what extent benthic communities respond to natural and man-made environmental change and to assess their role for nutrient cycling in the mangrove forest. Data will also be used to evaluate the nursery function of the SA Lagoon for fish, shrimp and mud crabs and thus its ecological and economic potential. Results

1. Diversity and spatio-temporal distribution of the benthic community