Mangrove Composition and Structure at Small Islands in Wakatobi National Park, Southeast Sulawesi

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1 Mangrove Composition and Structure at Small Islands in Wakatobi National Park, Southeast Sulawesi JAMILI 1, ASRUL SANI 2, RIYANTI DJALANTE 3, YULIUS B. PASOLON 4 1 Department of Biology, FMIPA, Universitas Halu Oleo, Jl. HAE. Mokodompit, No.1, Andunohu, Kendari INDONESIA jamili66@yahoo.com, 2 Department of Mathematics, FMIPA, Universitas Halu Oleo, Jl. HAE. Mokodompit, No.1, Andunohu, Kendari INDONESIA saniasrul2001@yahoo.com 3 Department of Environment, FHIL, Universitas Halu Oleo, Jl. HAE. Mokodompit, No.1, Andunohu, Kendari INDONESIA Riyanti.djalante@gmail.com 4 Department of Agriculture, Faculty of Agriculture, Universitas Halu Oleo Jl. HAE. Mokodompit, No.1, Andunohu, Kendari INDONESIA yulpas_59@yahoo.com Abstract: - This study aims to describe the structure and composition of mangrove vegetation and the abiotic factors in small islands at Wakatobi National Park (WNP), South East Sulawesi, Indonesia. Both Line Transect and Plot Methods were used in the vegetation sampling. Observation plots were continuously located along both sides of each transect line. Structure and composition of mangrove vegetation were determined through the analysis of the parameters; frequency (relative frequency), density (relative density), dominance (relative dominance), importance value index, species diversity index, natural regeneration, distribution of stem diameter, and status of mangrove community. Two test analysis were used; (1) ANOVA, to identify the difference in abiotic factors among islands, and (2) Duncan-test, to determine which abiotic factors that have significantly different responses (p=0.05). Twenty species of true mangrove were found at WNP and the largest number of species varieties was found in Kaledupa Island. The highest density of mangrove forest was also found in Kaledupa and the smallest density was in Derawa. The highest densities of Bruguiera gymnorrhiza (L.) Lamk. and Rhizophora mucronata Lamk. species were observed in Derawa. The diversity index of species was found low for all three islands. The mangrove species; Ceriops tagal (Perr.) C.B. Rob. and Ceriops decandra (Griff.) in Kaledupa and Osbornia octodonta F.v.M species in Hoga Island, were considered to have a good natural regeneration. Besides through seed/propagule dispersal, it was found that Rhizophora genus also regenerated vegetatively through branches. The abiotic factors that were considered to infulence on the distribution of mangrove species were wave protection, siltation, and the source of freshwater. The abiotic factors that had significant correlation to the pattern of mangrove vegetation were ph, available Kalium and salinity. However, the result shows that there is no significant correlation content of soil organic materials, total Nitrogen, available Phosphat and soil texture (silt, clay and sand) to the pattern of mangrove vegetation. The distribution of diameter was chategorized as J-shaped graph model which indicates that the population grows naturally. We suggested that the status of mangrove community in Wakatobi National Park is categorized in damage. This is mainly due to human activities such as the conversion to settlement and agricultural areas, and the illegal logging. Key-Words: - WNP, Abiotic factors, Pattern of Mangroves, Diversity Index ISBN:

2 1 Introduction Wakatobi archipelago is one of the smallisland ecosystems in Indonesia, which comprises around 48 islands, 3 hirsts and 5 atolls. Wakatobi is situated at 5 o 12' South Latitude and 6 o 10' South Latitude and 123 o 20' East Longitude and 124 o 39' East Longitude. It has been set as a conservation area with the name Wakatobi National Park (WNP), based on the Decree of Indonesian Forestry Minister, Number: 393/Kpts-VI/1996 (REF). Wakatobi National Park has around 1.39 million acres, which is overlapping with the administrative region of Wakatobi. Therefore, the management of WNP needs knowledge and understanding of the ecological biodiversity in the region. On the other hand, the local government has concentrated much to the infrastructure development for the increasing regional revenue. An integrated planning and design is necessary to ensure the sustainability and protection of mangrove ecosystems in WNP. Many factors need to be considered for a good management planning. The currently available studies related to WNP have discussed various issues such as the ecology of coral reefs, socioeconomic conditions, and the economic value of the resource; see for example, [6, 9, 11, 21]. However, there is no study yet that directly focuses on the mangrove vegetation in WNP. This is particularly on the information related to the ecological characters of mangrove vegetation in WNP. This elementary study is essential to achieve a sustainable management of mangrove areas. Understanding the structure of vegetation is important because it serves as the basis of ecological work was stated in [15]. According to [18], the structure of vegetation should be determined in advance in order to carry out an appropriate management on a sustainable basis. Moreover, [28] stated that the management of a dynamic landscape should be based on the process of vegetation as the basis of ecological process that takes place in an ecosystem. The level of disturbance and the number of factors that cause the decreasing function and the degradation of mangrove forests in WNP are quite high. The problems such as the plenty of filled garbage, the land conversion of mangrove and the mangrove wood extraction, which were observed during site visit, have caused the destruction of mangrove vegetation. This condition eventually leads to the decrease of WNP capacity to carry out its functions. Based on this evidence, it is essential to study the mangrove ecosystem in WNP and to provide an overview of the structure and composition of mangrove vegetation as well as to support in-situ conservation, research, education and tourism. 2 Method This study was conducted in three islands of Kaledupa, Derawa, and Hoga, located at Wakatobi National Park, Indonesia. The combination between Line Transect and Plot Methods was used in the vegetation sampling [22, 4]. Three line transects were created in each island, starting from the front formation (seaward) passing through the mangrove community in the island to the back formation (landward). The observation plots with size 10m by 10m were continuously created along both sides of each transect line. All mangrove structures inside the plots were observed; i.e., trees (dbh > 20 cm), trunks (10 19cm dbh), and sapling (dbh<10, height>1.5m), and seedling (stem height < 1.5). Data consisting of the number of individuals and the stem diameter at breast height (dbh) for each species were collected in each plot. The process of data collection was carried out in the following steps: (1) the measurement on the mangroves was taken if half or more the vegetation part belonged to the observation plot, (2) the diameter of a vegetation was measured at 130cm height above the ground, (3) if a vegetation has buttress with more than 130 cm height, then the measurement was taken at 20cm above the buttress, (4) if a vegetation has branches, then the diameter of the vegetation was measured at 130cm above the ground level (counted as one individu) and the diameter of all branches located less than 130cm above the ground was measured (each branch was counted as one individu), (5) the diameter of seedling was not measured but simply the number of seedling (individuals) was counted. All known species were recorded in the field and for those unknown species the herbarium specimens were taken. The identification process of the collected specimens was carried out in the Laboratory of Biology, Halu Oleo University, by comparing the specimens with the reference in [18, 24, 25]. Besides taking samples and recording of the mangroves, sample of substrate or soil was collected at five points in each plot, i.e., at all four corners and at the center of the square plot. The process of soil sampling was as follows: (1) ground at each point of sampling was drilled at 0-50cm in depth, (2) all collected soil from five sampling sites in each plot was then mixed and about one kilogram of the composite was taken as a sample, (3) the sample was analyzed in the laboratory, using the formula developed by [7] as follows. ISBN:

3 Density (K) Relative Density (Kr) Frequency (F) Relative Frequency (Fr) Dominance (D) Relative Dominance (Dr) Important Value (NP) 3 Data Analysis The diversity index of species was calculated by the formula of Shannon-Wienner. The natural mangrove regeneration was determined by the total density of mangrove seedling and saplings at each observation plot and the result was converted to acres. The distribution of flora and mangrove in WNP was determined by taking herbarium material with the cruise technique. The inventory path was done in two ways; (i) cruise the part of the islands where mangroves grow by motor boat during high tide, then (ii) follow the path from the front formation (seaward) passing trhough mangrove community to the back formation (landward) at each sample. The table shows that the number of species is not uniformly distributed in all islands. The largest number of species was found in Kaledupa and the least was in Derawa. Each island has various environmental characteristics required for the growth of mangroves. It was found that the size of the islands does not directly relate to the area covered with mangroves. For instance, Hoga is bigger than Derawa but the mangrove communities in Hoga is only found in one place whereas mangrove communities in Derawa can be found in several places, as depicted in Figure 1. Abiotic factors which are considered to have contributed to the distribution of mangrove community are waves, puddling, and freshwater [3, 27]. It was further found that waves around Kaledupa, both in the east and the west monsoon season, are relatively small compared to those in Derawa and Hoga. Moreover, Kaledupa is topographically protected by several surrounding islands and atoll. High siltation site due to erosion of agricultural land which is brought by rainwater and small rivers was also found only in Kaledupa. 4 Result and Discussion Kaledupa is the biggest island and Derawa is the smallest island from all islands select for study in WNP. The total number of mangrove species found in WNP was as many as 20 true species, which belong to 11 familia and they are dominated by Rhizophoraceae. Table 1 shows the true mangrove flora in Wakatobi National Park. Observations were made with a cruise technique in the mangrove communities in Kaledupa, Derawa, and Hoga. In Kaledupa, the exploration was done in the Village of Balasuna, Ollo, Buranga, Lagiwae, Ambeuwa, Laulua, Sombano, Horua, and Langge. In Derawa and Hoga, the exploration was carried out in all regions that have mangroves. ISBN:

4 Table 1. Mangrove Species Found in Wakatobi National Park Family Species Island Rhizophoraceae Rhizophora mucronata Lamk Rhizophora apiculata Bl Bruguiera gymnorrhiza (L.) Lamk Ceriops Tagal (Perr.) C.B. Rob Ceriops decandra (Griff.) Ding Hou Sonneratiaceae Sonneratia alba Smith Sonneratia caseolaris (L.) Engl Avicenniaceae Avecennia marina (Forsk.) Vierh Meliaceae Xylocarpus granatum Koenig Xylocarpus molucensis (Lamk.) Roem Combretaceae Lumnitzera littorea (Jack) Voigt Lumnitzera rasemosa Willd Myrsinaceae Aeguceras cornikulatum (L.) Blanco Osbornia octodonta F.v.M Lythraceae Phemphis aciduta Frost. & f Acanthaceae Acanthus ebracteatus Vahl Arecaceae Nypa fructicans Wurmb Euphorbiaceae Excoecaria agallocha L Pteridaceae Acrostichum speciosum Wild Acrostichum aureum Linn Jumlah Description: + = found, - = not found Table 2. The number of species per hectare Island (individu per hectare) Spesies P T Sp Se P T Sp Se P T Sp Se Rm Ra Bg Sa Sc Am Xg Ct , Cd , Oo Total ,571 6, ,014 1, ,248 3,182 Description; P=tree, T=pole, Sp=sapling, Se=seedling, Rm=Rhizophora mucronata Lamk., Ra= Rhizophora apiculata Bl., Bg=Bruguiera gymnorrhiza (L.) Lamk., Sa=Sonneratia alba Smith., Sc=Sonneratia caseolaris (L.)Engl., Am=Avecennia marina (Forsk.) Vierh., Xg=Xylocarpus granatum Koenig., Ct=Ceriops Tagal (Perr.) C.B. Rob., Cd=Ceriops decandra (Griff.) Ding Hou., dan Oo=Osbornia octodonta F.v.M. ISBN:

5 The location with enough fresh water supply into the mangrove communities was found only in Kaledupa. All these have become the reasons why Nypa fructicans Wurmb species are found only in Kaledupa but not in other two islands. It can be concluded that most environmental characteristics that support the growth of mangroves, such as wave protection, puddling, and freshwater sources, were found in Kaledupa. Thus, all these can be considered as the main factor for the wide distribution and high number of mangrove species in Kaledupa. The distribution of mangrove species has been extensively studied; see for example, [10]. Each mangrove species has its own ecological range and each type has a specific niche. All islands in this study are considered to posses typical environmental characteristics. It was found that the species of Rhizophora mucronata Lamk., Rhizophora apiculata Bl., Bruguiera gymnorrhiza (L.) Lamk., And Acanthus species ebracteatus Vahl., grow well in all islands. These species are common and widely spread in Wakatobi National Park. However, the species such as Xylocarpus sp., Lumnitzera sp., Aeguceras cornikulatum (L.) Blanco, Excoecaria agallocha L., Acrostichum spp., and Nypa fructicans Wurmb were found only in Kaledupa whereas Osbornia octodonta FvM species was found only in Hoga. The presence of mangrove communities in Wakatobi National Park plays a significant role in the ecological study. For example, to assess the ecological community (sin ecology) and ecological population (out ecology) of Nypa species fructicans Wurmb can only be carried out in Kaledupa, for Osbornia octodonta FvM species it can only be done in Hoga, and common species such as Rhizophora mucronata Lamk. and Bruguiera gymnorrhiza (L.) can be carried out in all islands, Kaledupa, Derawa, and Hoga. Thus, the persistence of mangrove communities in Wakatobi needs to be protected from further damage. trees, poles, and sapling for Rhizophora mucronata Lamk species was found in Derawa Island. For Gymnorrhiza Bruguiera (L.) Lamk species, the highest density of tree was also found in Derawa, but the highest density of pole and sapling was found in Kaledupa. Although Derawa has the least number of mangrove species but the island has the highest density of mangroves. In general, Kaledupa has the densest of mangrove species whereas Derawa has the least dense. This disparity relates to the different number of species found in the islands. It was found that the total density of each species varied among the islands. The highest density of Gymnorrhiza Bruguiera (L.) Lamk species was found in Derawa and the least one was found in Hoga. The highest density for Rhizophora mucronata Lamk. species was in Derawa and for Ceriops tagal (Perr.) C.B. Rob. Species was in Kaledupa Natural Regeneration of Mangrove Vegetation in Wakatobi National Park Table 3 shows that the density of seedling varies both among species and islands. However, most species have relatively low density of seedlings. The sampling is done with observation plot techniques with size 10m x 10m. The number of plots was 101 (in Kaledupa), 35 (in Derawa), and 23 (in Hoga). This indicates that most mangrove species in the islands have a small rate of natural regeneration and this rate has been considered as not normal. The low density of seedling in some mangrove species highly corralates to the low density of the mangrove trees, as presented in Table 4. Sampling with observation plot techniques with size 10m x 10m The Abundance of Mangrove Species in Wakatobi National Park The abundance of mangrove species in the Wakatobi National Park is shown in Table 2. The Density of mangrove vegetation (number of individuals per hectare) for several stratas; trees (dbh> 20 cm), pole (dbh cm), sapling (dbh cm), and seedlings (height> 1.5m and dbh <10 cm). Sampling with observation plot techniques with size 10m x 10 m. The number of plots was 101 (in Kaledupa), 35 plots (in Derawa) and 23 plots (in Hoga). As shown in Table 2, the highest density of ISBN:

6 Table 3. Density of mangrove vegetation (total individuals per hectare) in Wakatobi National Park. Species Density (total individuals per hectare) Rhizophora mucronata Lamk , Rhizophora apiculata Bl Bruguiera gymnorrhiza (L.) Lamk , Sonneratia alba Smith Sonneratia caseolaris (L.) Engl Avecennia marina (Forsk.) Vierh Xylocarpus granatum Koenig Ceriops Tagal (Perr.) C.B. Rob. 4, , Ceriops decandra (Griff.) Ding Hou 2, Osbornia octodonta F.v.M , Total 9,488 3,046 4,604 Table 4. Density of mangrove vegetation (total individuals per hectare) for seedlings (height> 1.5 m and dbh <10 cm) in Wakatobi National Park.. Species Density (total individuals per hectare) Rhizophora mucronata Lamk Rhizophora apiculata Bl Bruguiera gymnorrhiza (L.) Lamk Sonneratia alba Smith Sonneratia caseolaris (L.) Engl Avecennia marina (Forsk.) Vierh Xylocarpus granatum Koenig Ceriops Tagal (Perr.) C.B. Rob. 3, * Ceriops decandra (Griff.) Ding Hou 1,736.63* - - Osbornia octodonta F.v.M ,843.48* Jumlah 6,522 1,057 3,183 Description *: species with well or normal natural regeneration ISBN:

7 The number of plots was 101 (in Kaledupa), 35 (in Derawa), and 23 (in Hoga). According to the Indonesian Ministry of Forestry that on the management of mangrove/sylvikultur swamp forest, a mangrove community has a normal natural regeneration if the number of seedlings reaches 1,000 stems per hectare. Therefore, the species with a relatively good regeneration were Ceriops tagal (Perr.) CB Rob., and Ceriops decandra (Griff.) found in Kaledupa and Osbornia octodonta FvM species found in Hoga Diversity Index of Mangrove Species in Wakatobi National Park Table 5 shows the comparison of the index of the tropical rain forest, the diversity index of mangrove vegetation species in WNP is classified as low. The sampling are trees (dbh> 20 cm), pole (dbh cm), sapling (dbh cm), and seedlings (height> 1.5 m and dbh <10 cm) in Wakatobi National Park. Sampling with observation plot techniques with size 10m x 10m. The number of plots was 101 (in Kaledupa), 35 (in Derawa), and 23 (in Hoga). Table 5 indicates that the plants must adapt to the sea water with high salinity. Mangroves are plants with facultative halophyte where salinity is not essential for mangroves to growth and they grow well in the environments with fresh water. However, the benefit of high-salinity environments for the mangroves is that the number of other competing plants is low. Only a few types of plant can adapt in high salinity environments. In the tropical rain forest, such plant diversity and the competition both among and within species are very high. rural roads, boat landing). Also, mangroves are used as by the local community as firewood, poles on seaweed cultivation and fishing nets, and materials for house construction. On the other hand, there is no evidence that the damage of mangrove communities in Derawa and Hoga was due to human activities. Instead, the damage of the mangroves in the islands is mainly due to the low density of mangrove communities The Characteristics of Abiotic Environment of Mangrove Vegetation in WNP Table 7 shows the soil Chemical properties and soil texture (%) of mangrove vegetation in Wakatobi National Park. Sampling with observation plot techniques with size 10m x 10m. The number of plots was 101 (in Kaledupa), 35 (in Derawa), and 23 (in Hoga)Based on the correlation test as shown in Table 7, there is a significant correlation between the environmental factors and the pattern of mangrove distribution. However, Soil Organics, N (in total), P (available), and soil texture does not show a significant contribution to the pattern. This is probably due to that each pattern community has effect on habitat factors and success rate Status of Mangrove Community in Wakatobi National Park Table 6 shows the analysis of mangrove community status in WNP, with sampling with observation plot techniques with size 10m x 10m. The number of plots was 101 (in Kaledupa), 35 (in Derawa), and 23 (in Hoga) The above results show that the mangrove communities in all islands have been classified as damaged. Several factors have been considered as the causes of the mangrove destruction. In Kaledupa, the main causes are human activities either local community or government. For example, the land where mangroves commonly grew well has been converted into land for the residential communities, cultivated plants, and the construction of public facilities (schools, markets, ISBN:

8 Table 5. Diversity Index (H') of mangrove vegetation;. Vegetasi Strata Diversity Index (H ) Tree Pole Sapling Seedling Individuals in Total Table 6. The density of mangrove vegetation (individuals per hectare); trees and poles in Kaledupa, Derawa and Hoga Wakatobi National Park.. No. Species Island 1. Rhizophora mucronata Poir Rhizophora apiculata Blume Bruguiera gymnorrhiza Lamk Xylocarpus granatum Koe Sonneratia alba Smith Sonneratia caseolaris (L.) Engl. _ Ceriops tagal C B Rob Avecennia marina (Forsk) Vier Ceriops decandra (Griff.) D. Hou Osbornia octodonta F.v.M Total Statu Demgd Demgd Demgd Table 7. Soil Chemical properties and soil texture (%) of mangrove vegetation in Wakatobi National Park. Soil Abiotic Characteristics Island ph 6,15 a 7.24 b 6.11 a N-Total (%) 0.36 a 0.41 a 0.33 a P (ppm) a a a K (me/100 g) 0.28 a 0.31 a 0.51 b Soil Organic Material (%) a a a Salinity ( ) a a 6.5 b Sand Subtrate a a a Ash Subtrate a a a Liat Subtrate a a a Description: The same letter on each row indicates that the characteristics in both islands are not significantly different ( ) ISBN:

9 The result shows that soil ph has a significant correlation with the pattern of mangrove vegetation communities. The highest ph value was found in Derawa but it was still in the neutral category and the ph values in Kaledupa and Hoga belong to the slightly acid category. The ph lebel is important as it affects on the nutrient content of soil, necessary for pants to growth. The available Potassium in soil also has a significant correlation with the pattern formation of mangrove community. The potassium concentration available in Hoga is classified as medium and that in Kaledupa and Derawa belongs to be low concentration. The land of all mangroves in the islands is typically high salinity. The result of study also shows that the factor of soil salinity has empirically a significant correlation with the pattern of mangrove vegetation communities. Although mangroves generally have a high tolerance to salinity, compared with other types of plant, the tolerance to salinity varies among species of mangrove. For example, the seedling of Rhizophora mucronata Lamk. sp grows well at 30% of salinity, Rhizophora apiculata Bl. species grows well at 15% of salinity (Kathiresan & Thangam, 1990; Kathiresan et al. 1996b), Sonneratia alba Smith grows well at salinity between 2%-18%, and the type of Sonneratia lanceolata is only able to adapt to the salinity level at 2% (Ball and Pidsley, 1995). In general, mangroves grow much better at low salinity [14]. The experimental results showed that mangroves with high salinity consume more energy to maintain water balance and ion concentration than to primary productivity and growth [5]. On the coast of Pasific Central America, freshwater sources (mostly from rainfall and runoff/runoff) has influenced on phenological productivity, growth, and death of Avicennia bicolor species [12]. Mangroves have less competitive than other types of plant in the low-salinity areas. For example, rivarian mangroves in America have disappeared in the estuary of the Amazon and the Orinoco and they were replaced by a group of freshwater macrophyte plants. High salinity level also affects on the mangrove species. For example, high salinity level reduces Bruguiera gymnorrhiza biomass [23], and leads to changing in the seddling bud of Rhizophora mangle [17]. High salinity reduces the size of leaf, increases leaf osmotic pressure, increase the ratio between the leaf area/weight and the decrease of total N, K and P [20]. 5 Conclusion It was found that there are as many as 20 true mangrove species In Wakatobi National Park where they belong to 11 families, dominated by Rhizophoraceae familia. The highest density of individuals for all species at all levels of growth structure was found in Kaledupa and the lowest desity was found in Derawa. The highest density of Gymnorrhiza Bruguiera (L.) and Rhizophora mucronata Lamk species was found in Derawa but the highest density of For Ceriops tagal (Perr.) C.B. Rob. Species was found in Kaledupa. The success rates of natural regeneration for the species such as Rhizophora mucronata Lamk., Rhizophora apiculata Bl., Bruguiera gymnorrhiza (L.) Lamk., Sonneratia caseolaris (L.) Engl., Avicennia marina (Forsk.) Vierh., and Xylocarpus granatum Koenig, are considered to be low. However, the species such as Ceriops tagal (Perr.) CB Rob., and Ceriops decandra (Griff.) in Kaledupa and Osbornia octodonta FvM in Hoga have relatively a good natural regeneration. Species Diversity Index of mangrove vegetation in WNP is classified as low, especially when it is compared with the index for the tropical rain forest. The low diversity of mangrove species WNP more likely relates to the environment with high salinity. Stand structure of all mangrove species with distribution parameters of stem diameter class in Wakatobi National Park belongs to L-type or J inverted curve shape which are included in the category uneven-aged stand graph. Such form is one of the characteristics of the population with natural growth. Xylocarpus granatum species in Kaledupa, Rhizophora mucronata Lamk. species in Derawa and Sonneratia alba Smith species in Hoga are included in the category of stands with irregular shape. The stand model with irregular graph indicates that the growth of population has been disrupted either naturally or unnaturally. The status of mangrove communities in Wakatobi National Park is categorized in the criteria as destructed. Several factors that cause the destruction of mangrove communities in Kaledupa are the conversion of mangroves into residential communities, land cultivated plants, construction of public facilities, and the use of mangroves as wood, poles /stakes for the cultivation of seaweed and fishing nets as well as materials for house. However, the evidences that the destruction of mangrove communities in Hoga and Derawa were due to human or natural activities were not found. The destruction of mangroves in both islands is mainly due to low average density of individu per hectare. The study shows that soil environment such as ph, Potassium and salinity, has a significant correlation to the pattern of mangrove community but soil organic matterial, Nitrogen (total), ISBN:

10 phosphate (available) and soil texture does not show a significant contribution. Mangrove ecosystem in the small islands of Wakatobi National Park is an edge ecosystem which is generally present on sandy substrate environment, coral debris and dead coral. Such substrates are relatively vulnerable to any changing due to various natural and non-natural disturbances. Therefore, the existing mangrove ecosystems need to be preserved and developed by setting all existing mangrove areas as conservation areas. The potentials of the existing mangrove resource needs to be studied in more intensive and developed as a centre of mangrove study (building mangrove research stations) on the small islands. The Kaledupa is as the representative of the largest island with the largest population and relatively the most available fresh water. Hoga is the representative of the inhabited island with the limited available fresh water whereas Derawa Island is to represent the smallest island with population but limited the available fresh water. References: [1]. Ball, M.C., Pidsley, S.M Growth response salinity in relation to distribution of two mangrove species, Sonneratia alba dan S. lanceolata, in Northern Australia. Functional Ecology, 9,77-85 [2]. Barbour, M.G., J.H. Burk, W.D. Pitts Terrestrial Plant Ecology. California : The Benjamin Cumming Publising Company Inc. [3]. Chapman, V.J Mangrove Vegetation. J. Cremer Publ. Leutherhausen, Germany [4]. Cintron G., A.E. Lugo, R. Martinez, Structural and functional properties of mangrove forests. Symposium signaling the completion of the Flora of Panama. Panama City, University of Panama. [5]. Clough, B. F Growth and salt balance of the mangrove A. marina in south-eastern Australia. Aust. J. Bot. 39: [6]. COREMAP. Coral Reef Rehabilitation and Management Program Base Line Study Wakatobi Sulawesi Tenggara. CRITC- LIPI, Jakarta. [7]. Cox, G.W Laboratory Manual of General Ecology. Iowa : W.M.C. Broown Company Publisher. [8]. Daniel, T.W.,J.A. Helms., F.S. Hocker, Prinsip-Prinsip Silvykultur. Edisi Kedua. Terjemahan. Gadjahmada University Press, Yogyakarta. In Indonesian. [9]. Dhewani, N dkk., Studi Baseline Ekologi Kabupaten Wakatobi-Sulawesi Tenggara. Coral Reef Information Centre, Lembaga Ilmu Pengetahuan Indonesia, Jakarta. In Indonesian. [10]. Ellison AM, Farnsworth EJ, Merkt RE Origins of mangrove ecosystems and the mangrove biodiversity anomaly. Global Ecology and Biogeography 8: [11]. Hidayati, A., Ngadi, Daliyo Kondisi Sosial Ekonomi Masyarakat di Lokasi Ceremap II: Kasus Kabupaten Wakatobi. CRITC-LIPI, Jakarta. In Indonesian. [12]. Jiménez, J.A. (1990). The structure and function of dry weather mangroves on the Pacific coast of Central America, with emphasis on Avicennia bicolor forests. Estuaries 13 (2), [13]. Kathiresan, K., Thangam, T.S. (1990). A note on the effects of salinity and ph on growth of Rhizophora seedlings. The Indian Forester 116 (3), [14]. Kathiresan, K., Thangam, T.S., Bose, K.S. (1990b). Effect of lates of Excoecaria agallocha L. on marine productivity. In Perspectives in Phycology (V.N. Raja Rao, ed.), pp Today and Tomorrow s Publishers, New Delhi. [15]. Kershaw, K.A Quantitative and Dynamic Plant Ecology. 2 en.ed. The English Language Book Society and Edward Arnold (Publisher) Ltd, London. [16]. Kint, A De luchtfoto en de topografische terreingesteldheid in de mangrove. De Tropische Natuur, 23: [17]. Koch, M.S., Snedaker, S.C. (1997). Factors influencing Rhizophora mangle L. seedling development in Everglades carbonate soils. Aquatic Botany 59 (1-2), [18]. Kusmana, C A Study on Mangrove Forest Management Based on Ecologycal Data in East Sumatera, Indonesia. Kyoto University, Japan. [19]. Kusmana, C., Suhardiono, Sudarmadji, dan Onrizal Mengenal Jenis-Jenis Pohon Mangrove di Teluk Bintuni Irian Jaya. Fahutan IPB-Bogor. In Indonesia. [20]. Medina, E., Lugo, A.E., Novelo, A. (1995). Mineral content of foliar tissues of mangrove species in Laguna de Sontecomapan (Veracruz, Mexico) and its relation to salinity. Biotropica 27 (3), [21]. Mufti, A.T., Penilaian ekonomi Sumberdaya Hutan Mangrove di Pesisir Pulau Kaledupa Kabupaten Wakatobi. [tesis]. Surabaya. Program Pasca Sarjana, Institut ISBN:

11 Teknologi Sepuluh Nopember Surabaya. In Indonesia. [22]. Muller-Dumbois, D., Ellenberg, H Aims and Method of Vegetation Ecology. New York : John Wiley & Sons. [23]. Naidoo, G. (1990). Effects of nitrate, ammonium and salinity on growth of the mangrove Bruguiera gymnorrhiza (L.) Lam. Aquatic Botany 38 (2-3), [24]. Noor, R.Y., Khazali, M., Suryadiputra, I.N.N, Panduan Pengenalan Mangrove di Indonesia. PHKA/WI-IP-Bogor. In Indonesian. [25]. Onrizal, Rugayah, Suhardjono, Flora Mangrove Berhabitus Pohon di Hutan Lindung Angke-Kapuk. Biodiversitas, Volume 6, Nomor 1 Halaman: [26]. Rasman, M (2007). Penilaian Ekonomi Sumberdaya Alam di Kabupaten Wakatobi. [tesis]. Bogor. Sekolah Pasca Sarjana Institut Pertanian Bogor. In Indonesian. [27]. Soekardjo, S Natural regeneration status of commercial mangrove species (Rhizophora apiculata and Bruguiera gymnorhiza) in mangrove forests of Tanjung Bungin, Bunyuasin District, South Sumatra. Forest Ecol. Mgmt 20, [28]. Spies, T.A., M.G. Tunner, Dynamic Forest Mosaic in Monitoring Biodiversity in Forest Ecosystem. Edited by Hunter, M.L, Jr. Cambridge University Press, Cambridge. ISBN: