Bogor, 21-22 October 2015
464 Other supporting data were also collected. The local community activities in the interaction
with mangrove forest were observed by interview with key person. Literature study for the recent status of wildlife in Balikpapan Bay mangrove forest also had been done to support the
result.
2.3 Analysis
Parameter of vegetation analysis referred to Cottam and Curtis 1956 that consisted of relative density, relative dominancy and relative frequency. According to Soerianegara and
Indrawan 1988, Importance Value Index IVI for sapling and tree is the sum of relative density, relative dominancy and relative frequency.
IVI = Relative density + Relative Dominancy + Relative Frequency For seedling stage, IVI is the sum of relative density and relative frequency.
3. RESULT AND DISCUSSION 3.1 Structure of mangrove forest
Based on the data, Balikpapan Bay mangrove forest consisted of 19 species. The number of species found in study site is higher if compared to other mangrove forest. As reported by
Darmadi and Ardhana 2010, Perapat Benoa mangrove forest in Bali only consisted of 7 mangrove species, and Tombariri Minahasa mangrove forest was dominates only by 3
mangrove species : R. apiculata, A. alba and S. alba Nauw, 2012. Relevant study also had been reported by Sayektiningsih et al. 2012 that specifically in Benawa Besar island, one of the
small island located in Balikpapan bay. It was reported that on that site was comprised of 8 mangrove species and dominated by R. mucronata.
Figure 2: Distribution of tree diameter at Balikpapan Bay mangrove forest Based on the distribution of tree diameter as shown on Figure 2, tree with the diameter of 21
cm - 30 cm is the largest amount of vegetation in Balikpapan Bay mangrove forest. This was consisted of 15 species, and dominated by Rhizophoraapiculata. The least amount of vegetation
was the tree with the diameter 50 cm which consisted of 3 species. Figure 2 showed that the natural regeneration of Balikpapan bay mangrove forest was not normal because the number
of the individu at the diameter class of 0-10 was lower than the bigger diameter. But starting from diameter 21-30 cm to 51 cm, the natural regeneration demonstrated the normal
100 200
300 400
500
0-10 11-20
21-30 31-40
41-50 51
N H
a
Diameter class cm
Bogor, 21-22 October 2015
465 pattern. According to Meyer 1952 on Onrizal and Sukmana 2006, forest with the tree
diameter distribution like τL” curve said to be balanced forest that consisted mainly with the small diameter tree and the big diameter tree as the least number in the tree distribution. But
in Balikpapan bay, it did not follow the pattern of balanced forest. It can be said that the regeneration of the mangrove forest was not normal and endanger. It can be shown from the
density of tree, sapling and seedling stage is lower than 1000Ha. Based on Keputusan Menteri Lingkungan Hidup No. 201 Tahun 2004 about Kriteria Baku dan Pedoman
Penentuan Kerusakan Mangrove Kementerian Lingkungan Hidup, 2004, Balikpapan Bay mangrove forest can be categorized as damaged mangrove forest. The less number of trees
with diameter 0-10 cm and 11-20 cm probably caused by the utilization of this class diameter trees for firewood and charcoal manufacture by local community.
The distribution variation of diameter class showed the different ability of trees to utilize solar energy, nutrient and competition Kalima, 2008. Mangrove habitat that has the normal natural
regeneration could be found in the downstream of SungaWain Noorhidayah, et al., 2007
3.2 Species composition and domination 3.2.1
Composition of vegetation Result showed that mangrove ecosystem at Balikpapan Bay was composed of 20 species and
17 families Table 1. The habitus of the vegetation were tree, bush, climber and palm.
Table 1: Species found in Balikpapan bay mangrove forest
Rhizophoraapiculata, Disoxylumsp, Sonneratiaalba, Rhizophoramcronata, Avicennia marina and Bruguiera gymnorhiza were found in all growth stages seedling, sapling and tree. Most of the species had
the tree habitus. Only Flagellaria sp that had habitus as climber, and Pandanus odoratissima as bush.
No Species Family
Habitus
1 Rhizophora apiculata
Rhizophoraceae Tree
2 Rhizophora mocronata
Rhizophoraceae Tree
3 Sonneratia alba
Sonneratiacea Tree
4 Acrosticum aureum
Pteridaceae Bush
5 Ardisia sp
Primulaceae Tree
6 Avicennia marina
Verbenaceae Tree
7 Bruguiera gymnorhiza
Rhizophoraceae Tree
8 Ceriops tagal
Rhizophoraceae Tree
9 Dillenia suffruticosa
Dilleniacea Tree
10 Dysoxylum sp
Meliacea Tree
11 Flagellaria sp
Flagellariaceae Climber
12 Glochidion littorale
Euphorbiacea Tree
13 Guioa sp
Sapindaceae Tree
14 Heritiera littoralis
Sterculiaceae Tree
15 Lumnitzera littorea
Cumbretaceae Tree
16 Nypa fruticans
Palmae Palm
17 Pandanus odoratissima
Pandanaceae Bush
18 Pouteria sp
Sapotaceae Tree
19 Xylocarpus granatum
Meliaceae Tree
20 Cerbera manghas
Apocynaceae Tree
Bogor, 21-22 October 2015
466 It can be inferred that Balikpapan Bay mangrove forest is Rhizophora apiculata community
because it was mainly dominated by Rhizophora apiculata. R. apiculata dominated in seedling, sapling and tree category.
3.2.2 Tree phase
Balikpapan Bay mangrove forest at the tree stage was composed by 10 species. It was dominated by Rhizophora apiculata which had IVI 177.63 followed by Dysoxylum sp IVI
41.29 and Sonneratia alba IVI 38.54 . Species composition based on IVI was presented on Table 2.
Table 2: Species domination based on Importance value index of tree category in Balikpapan Bay mangrove forest
No Species
Relative density
Relative frequency
Relative dominance
Importance Value Index
1 Rhizophora apiculata
78.47 25.74
73.41 177.63
2 Dysoxylum sp.
12.76 11.44
17.08 41.29
3 Sonneratia alba
2.22 34.32
1.99 38.54
4 Avicennia marina
2.77 5.72
3.34 11.84
5 Ardisia sp.
0.55 5.72
0.48 6.75
6 Heritiera littoralis
0.44 5.72
0.50 6.67
7 Bruguiera sp.
1.11 2.86
2.30 6.27
8 Guioa sp.
0.89 2.86
0.43 4.18
9 Xylocarpus granatum
0.44 2.86
0.32 3.62
10 Rhizophora mucronata
0.33 2.86
0.13 3.33
3.2.3 Sapling stage
Vegetation on sapling stage was consisted of 14 species. On this stage, Rhizophora apiculata dominated with IVI 168.71 , followed by Sonneratia alba 35.54 , and Rhizophora mucronata
IVI 35.08 . Table 3 provided the species domination based on IVI of sapling category.
Table 3: Species domination based on Importance value index of sapling category in Balikpapan Bay mangrove forest
No. Species
Relative density
Relative frequency
Relative dominance
Importance Value Index
1 Rhizophora apiculata
63.88 38.45
66.38 168.71
2 Sonneratia alba
15.39 3.44
16.70 35.54
3 Rhizophora mucronata
1.82 31.57
1.69 35.08
4 Dysoxylum sp.
6.18 1.72
5.28 13.18
5 Avicennia sp.
3.27 5.17
2.21 10.65
6 Ardisia sp.
3.03 5.74
1.36 10.13
7 Heritiera littoralis
2.42 1.15
2.95 6.52
8 Bruguiera sp.
0.97 4.02
0.74 5.73
9 Cerbera manghas
0.61 2.87
0.53 4.01
10 Guioa sp.
1.09 1.15
0.96 3.20
11 Xylocarpus granatum
0.85 0.57
0.84 2.27
12 Ceriops tagal
0.24 1.72
0.34 2.30
13 Glochidion littorale
0.12 1.72
0.02 1.86
14 Pouteria sp.
0.12 0.57
0.01 0.70
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467 3.2.4
Seedling stage Vegetation at the seedling stage was consisted of 13 species. Species with the highest
Importance Value Index IVI is Rhizopora apiculata 81.63, followed by Acrosticum aureum 32.33 and Nypa fruticans 26.75. Species domination based on IVI of seedling category
was presented on Table 4.
Table 4: Species domination based on Importance value index of seedling category in Balikpapan Bay mangrove forest
No. Species
Relative density Relative frequency
Importance Value Index
1 Rhizophora apiculata
30.39 51.24
81.63 2
Acrosticum aureum 21.54
10.79 32.33
3 Nypa fruticans
17.31 9.44
26.75 4
Avicennia marina 16.15
5.39 21.55
5 Sonneratia alba
7.31 9.44
16.75 6
Rhizophora mucronata 3.85
2.70 6.54
7 Pandanus tectorius
0.77 2.70
3.47 8
Xylocarpus granatum 0.77
1.35 2.12
9 Bruguiera sp.
0.38 1.35
1.73 10
Flagellaria sp. 0.38
1.35 1.73
11 Allophylus cobe
0.38 1.35
1.73 12
Dillenia suffruticosa 0.38
1.35 1.73
13 Scleria sp.
0.38 1.35
1.73
Rhizophora apiculata dominated the composition of vegetation at seedling, sapling and tree category. It can be said that R. apiculata has the high competition ability and adaptivity at
Balikpapan Bay mangrove forest. The regeneration of R. apiculata also has been secured because the dominancy and the density at the seedling and sapling category were much higher
than other species.
3.3 Implication for conservation
3.3.1 Importance of Balikpapan Bay mangrove ecosystem to support wild life
Among many species living in the mangrove ecosystem, the proboscis monkey recognized as the important species that got many attention from the researchers. The proboscis monkey
Nasalis larvatus is endemic to the island of Borneo and considered ‘vulnerable’ according to
the IUCN threat criteria IUCN, 1996 and was given a ‘very high’ conservation rating by
Eudey 1987. N. larvatus is typically associated with coastal forest, including mangroves, and riverine, peat swamp and fresh water swamp forests. According to Meijaard and Nijman
2000, Balikpapan Bay is one of the priority areas for the protection of proboscis monkey in Kalimantan.
Mangrove degradation affected the existence of the proboscis monkey. The main factors contributing to proboscis monkey habitat destruction are land conversion for industrial and
urban use, logging both legal and illegal, settlement, swamp reclamation and embankment.
Land-cover loss in Balikpapan Bay mangroves was estimated by Langner et al. 2007 to be almost 8 yr−1 Stark et al., 2012. However, this conversion rate is based on the years of
shrimp farming conversion,which has now slowed down substantially, particularlyin Balikpapan Bay. While halving the estimated values from Langner et al. 2007 to 4 may still
bean over-estimate, it is nonetheless retained here due to the current land conversion for industrial and urban use Stark et al., 2012.
Bogor, 21-22 October 2015
468 The habitat degradation will impact the number of population of the proboscis monkey.
Meijaard and Nijman 2000, reported indication of population size was about 100 – 1000
individuals in Balikpapan Bay. Stark et al. 2010 using Population Viability Analysis PVA program Vortexv 9.95 predicted that population of the proboscis monkey in Balikpapan Bay
will be extinct in the next 14 years if the current situation remains unchanged. This condition needs important strategies to be developed based on the characteristics of individual
populations and their habitat, targeting the factors with the most influence on the survival and trends of the population Stark et al., 2012. Habitat protection is the most important aspect in
order to support the live survival of proboscis monkey. Habitat protection must become the interest of not only the government, but also the local communities and conservation
organization to enforce protection of their habitat. By working together, these groups can help to raise awareness and play an active role in the conservation of the mangroves. Some other
conservation strategies also can be implemented in conservation of proboscis monkey such as: designation of protection area, socialization to the communities, ecotourism, translocation and
ex-situ conservation, habitat protection Atmoko, et al., 2012. 3.3.2
Conservation by the community Balikpapan Bay is an important site for not only ecological meaning but also for economic
aspect. Located between two administrative regions Balikpapan city and PenajamPaser Utara district, this bay is now an important area for economic growth in Balikpapan that there are
many industrial activities take place. This bay is also important for transportation. The constructions of many facilities such as ports, power plant and factories has been endangered
the sustainability of the mangrove forest at Balikpapan Bay. The development of Kawasan Industri Kariangau KIK that located at the bay has affected the ecosystem of the mangrove
forest. Some of the local communities experienced the effect of the environmental alteration cause by
mangrove disturbance, such as flood, storm and abrasion that damage their residence. Because of that incident, local community located at Graha Indah village initiated the self-supporting
mangrove conservation, named Graha Indah Mangrove Center. They planted the damaged mangrove forest and protect mangrove forest from the disturbance. The activity is now
getting the attention from local government, corporation and public that supported their activity. Now the activity not only focused on the plantation of mangrove forest, but also for
ecotourism of mangrove forest and empowering local community. Based on the data, the primary mangrove forest has the potency for natural regeneration of
mangroves. Plant species richness in seedling and sapling stages could guarantee the sustainability of forest in the future of Balikpapan Bay. Even though Balikpapan bay is facing
some ecological danger, but it still has the potency for conservation through natural regeneration and local community awareness.
4. CONCLUSION
