VEGETATION’S STRUCTURE AND COMPOTITION
TO SUPPORT THE JAVAN GIBBON (hylobates moloch) HABITAT SUSTAINABILITY
IN GUNUNG HALIMUN NATIONAL PARK
Titien Suryanti Rostian
Trisakti University
Faculty of Architecture Landscape and Environment Technology
Jl. Kyai Tapa No 1 Grogol, Jakarta 11440,Indonesia
E-mail; titiensr@yahoo.com
VEGETATION’S STRUCTURE AND COMPOTITION
TO SUPPORT THE JAVAN GIBBON (hylobates moloch) HABITAT SUSTAINABILITY
IN GUNUNG HALIMUN NATIONAL PARK
T. Suryanti Rostian
Trisakti University
Faculty of Architecture Landscape and Environtment Tecnology
Jl.Kiyai Tapa No 1 Grogol, Jakarta 11440,Indonesia
E-mail; titiensr@yahoo.com
Abstract
Increased population and development growth at the conservation territory, affect the disturbance of landscape’s structure and function. This matter occurs as a consequence of the facilities to support human activity. Mount Halimun National Park territory supports biggest population of Javan Gibbon (Hylobates moloch) in Java. Factors affecting the forests destruction in Gunung Halimun are: transportation facilities, tea farming enclave, and gold mining. The present study is a part of the landscape analysis for conservation and management of Javan Gibbon in Mount Halimun National Park. The study was conducted on Mount Kendeng in the Javan Gibbon habitat, at the Mount Halimun, West Java. Elevation of the park area ranges from 570 m asl to 1929 m asl. The wide ranges of altitudes have diverse ranges of habitat types and also floristic composition. This research aims to analyze vegetation’s structure and composition in Javan Gibbon Habitat. Plant selection is very important step in the landscape design sequence and to support Javan Gibbon habitat sustainability. We recorded 64 species of trees with DBH > 10 cm in 25 families, with density of 406 trees/hectare and total basal areas of 35,30 m2. Species richness is low, the typical of mountain forests on West Java.
Keyword: Composition, structure vegetation, primate habitat, national park.
Introduction
Mount Halimun National Park (MHNP) territory support biggest population of Javan Gibbon (Hylobates moloch) in Java (Asquith et al, 1995). This territory also represent habitat which for many endangered species like Javan Eagle (Spizaetus bartelsi), Leopard (Panthera pardus), and Grizzled Monkey Leaf (Presbytis comata) (Yoneda et al, 2001). In MHNP, Javan Gibbon usually found especially in primary forest habitat, together with big of group (around 30 groups), with each group consist of 2 until 4 individual (Sugardjito & Sinaga, 1997). To observe Javan Gibbon, conservation ecological studies needs to be done in MHNP as Javan Gibbon habitat which still remained in the world.
Increasing population and development growth at the conservation territory, affect on the disturbance for structure and function of landscape. Other factor which effecting the ecological function in MHNP landscape are: farming encroachment, tea farming enclave in the middle of MHNP territory, and gold mine in the west part of territory (Asquith et al, 1995).
Other threat which annoying the ecological in MHNP landscape is this park has loss 2% of its forest in last 10 years (Yoneda et al, 2001). The existence of threat causing an annihilation of vegetation at some zonation, destruction of certain vegetation can result the loss of chosen food for primate, because certain type of trees is very meaningful. Destruction of forest substratum will pursue the regeneration, and in the end will causing the degradation of primate population (Marsh et al, 1987).
On Java, Steenis (1972) synthesized available qualitative information on vegetation and ecology, and identified the montane zone (100 – 2,400 m asl) and subalpine zones (>2,400 m asl). Based on some explorations in mount Halimun, Wiriadinata (2002) recorded 845 plant species in 436 genera and 125 families, slightly lower than the flora of the mount Gede-Pangrango (Sunarno & Rugayah 1992). The wide ranges of altitudes have diverse ranges of habitat types and also floristic composition. The present study is a part of the landscape analysis for conservation and management of Javan Gibbon in the MHNP.
Method
The study was made in the Javan Gibbon habitat, a small part of the Mount Halimun National Park, West Java . The park lies between the 6º 37′ and 6º 53′ S latitudes, and 106º 16′ and 106º 38′ E longitudes. The area was originally designated as a protection forest in 1924, and in 1979 it was expanded and was proclaimed as a nature reserve (Yoneda et al, 2001). The area was then declared a national park in 1992, covering a total area of 40,000 Hectares. Elevation of the park area ranges from 570 m to 1,929 m asl.
A plot of one hectare (20 x 500 m) was established in a primary forest with a canopy cover of about 70 – 80% within the forest area identified as the most suitable habitat for Javan Gibbon at the mount Kendeng area within the MHNP. The plot was constructed by initially establishing a 20 x 20 m subplot, which was subsequently expanded by incrementally adding a series of subplots up to a total area of one-hectare, thus the plot forms a transect consisting of 25 subplots. It lies on a hilly topography with the elevation range of 1,100 m to 1,200 m asl.
All trees with DBH ≥10 cm were enumerated and identified, their diameters were measured, and their heights were estimated. Calculation of density, frequency, basal area and importance value follows the standard procedure of Mueller-Dombois and Ellenberg (1974). The voucher specimens were collected for identification at the Herbarium Bogoriense at Bogor. The nomenclature follows Backer & Bakhuizen van den Brink, Jr. (1958-1968).
Results and discussion
Composition
The result of the inventory of trees with DBH ≥10 cm shows that 64 species in 25 families represented by 406 individuals with the total basal area of 35.30 m² occurred in the one hectare plot sampled.
Table 1 indicates ten most common families according to the total species important values for families (TSIVF). It shows that the mount Kendeng forest was dominated by Fagaceae (70.65%), which was represented by the genera Castanopsis, Lithocarpus, and Quercus. The other prevailing families were Hammamelidaceae, Myrtaceae, Theaceae, and Lauraceae. It should be noted that both in terms of importance values and number of species Fagaceae and Lauraceae are prevalent.
Macaranga javanica and Macaranga triloba were present in diameter classes up to 60 – 70 cm in height classes up to B layer. The high Importance Values of Hammamelidaceae is attributed to the high density and basal area of the single species of Altingia excelsa (Tables 2, & 3 ).
No
Family
TSIVF
1
Fagaceae
70.65
2
Hammamelidaceae
50.01
3
Myrtaceae
31.09
4
Theaceae
22.29
5
Lauraceae
20.14
6
Euphorbiaceae
17.65
7
Icacinaceae
15.79
8
Rutaceae
11.59
9
Rosaceae
10.87
10
Clusiaceae
9.05
T O T A L
259.13
(86.37%)
Table 1. Ten most common families according to the Total Species Importance Values for Families (TSIVF) in one hectare plot of a montane forest at the Mount Halimun National Park, West Java.
No
Species
IV
1
Altingia excelsa
50.01
2
Castanopsis javanica
22.53
3
Castanopsis acuminatissima
22.44
4
Schima wallichii
19.53
5
Syzgium sp
17.90
6
Euodia latifolia
11.59
7
Syzygium laxiflorum
11.08
8
Prunus arborea
10.87
9
Platea excelsa
9.50
10
Garcinia rostrata
9.05
T O T A L
184.50
(61.50%)
Table 2. Ten leading tree species based on Importance Values (IV) in one hectare plot of a montane forest at the Mount Halimun National Park, West Java.
No
Species
Density (tree/ha)
1
Altingia excelsa
34
2
Castanopsis acuminatissima
32
3
Syzqium sp
29
4
Schima wallichii
25
5
Euodia latifolia
24
6
Castanopsis javanica
22
7
Prunus arborea
20
8
Garcinia rostrata
16
9
Syzqium laxiflorum
15
10
Platea exelsa
11
T O T A L
228
(56.15%)
Table 3. Ten leading tree species according to the Density (D) of trees in one hectare plot of a montane forest at the Mount Halimun National Park, West Java.
The situation above is comparable to those at other sites on the mount Halimun (Simbolon & Mirmanto 1997; Mirmanto & Simbolon 1998; Yoneda et al. 2001) and the mount Gede-Pangrango (Meijer 1959; Yamada 1975, 1976a & b, 1977, 1990; Abdulhadi et al. 1998). The similarity of floristic composition between the present plot and another one-hectare plot at comparable elevation at Cisarua in the MHNP (Simbolon & Mirmanto 1997) is small, with a Jaccard’s similarity index of 13.6%.
The two most common and leading species in both mount Halimun and mount Gede-Pangrango are Altingia excelsa and Schima wallichii. Castanopsis and Lithocarpus are present in all but species that become locally prevalent in each site at both mount Halimun and mount Gede-Pangrango may vary.
In order to determine whether the 64 species recorded in the one hectare plot represent the total number of species in the area studied, a species-area curve was constructed (Figure 1). It shows the curve of cumulative increment of number of species in accordance with the increase of area. It is evident that the number of species within this hectare-plot increases rapidly and beginning to flatten out at around one hectare. The shape of this curve is comparable to that of other sites at mount Halimun (Kartawinata 2005), but the number of species in the hectare plot there is 55, lower than the present one (64).
In the latter two curves, each reaches the point of inflection at one hectare, where the minimum area can be attained at this point, indicating the beginning of the decrease of species richness, which reflects also the decrease of species diversity.
Figure 1. A species-area curve for trees with DBH ≥10 cm in a one hectare plot of a montane forest at the Mount Halimun National Park, West Java, by plotting the number of species against the area.
Structure
Figur 3 shows the basal areas of ten leading species that amounted to 25.06 m² or 71% of the total. It is clear also that six of the species belong to family Hammamelidaceae, Theaceae, Fagaceae, and Icacinaceae. Altingia excelsa was the most prominent species with the basal area of 12 m². Table 4 shows ten leading species according to the tree density with total of 228 trees/ha or 56% of the total density in the plot.
The diameter class distribution of trees in one hectare plot is presented in Figure 2 and Figure 3, which show to a smaller extent a typical size class graph of a tropical undisturbed primary forest. It reveals that 75.61% of the trees were less than 30 cm DBH. Only 24.39% occurred with diameters greater than 30 cm. Altingia excelsa, Castanopsis javanica and Schima wallichii were prominent in almost all diameter classes and at diameter of 100 – 140 cm all trees were Altingia excelsa. Other large trees with diameter of 50 – 100 cm were Castanopsis acuminatissima, Castanopsis tungurrut, Lithocarpus sp, Platea excelsa, and Syzygium sp.
Figure 2. Diameter class distribution of trees with DBH ≥10 cm in one hectare plot of a montane forest at the Mount Halimun National Park, West Java.
Figure 3. Number of tree species with DBH ≥10 cm according to the diameter classes in one hectare plot of a montane forest at the Mount Halimun National Park, West Java.
Figure 4 shows a simulated profile diagram constructed by plotting the data on tree height, and tree numbers reflecting the sequence of field records positioned in a linear row. Based on this diagram and height classes (Figure 6), the forest canopy (Whitmore, 1984) may be stratified into five strata and Figure 5 indicates the number of species within each stratum:
(A) The emergent, representing the uppermost layer (30-55 m), contains 11 species, but 40 % of the trees were Altingia excelsa; (B) Upper canopy (20-29.9 m) contains 26 species and the prevalent trees were shared by Altingia excelsa (14.7%), Castanopsis acuminatissima (13.2%), Castanopsis javanica (10.3 %) and Schima wallichii (13.2%); (C) Main canopy (10-19.9 m) is shared by 57 species and four species mentioned in B were still prevalent but at lower proportion; and (D) Lower canopy (5-9.9 m) comprises 38 species and none of them becomes prevalent.
Figure 4.
A simulated profile diagram of a one- hectare plot of a montane forest at the Mount Halimun National Park, West Java, showing five strata: A = >30 m; B = 20-29.9 m; C =10-19.9 m, and D = 5-9.9 m. The diagram was constructed according to the data on tree heights and tree numbers, reflecting the sequence of field records positioned in a linear row.
Conclusion
The forest investigated has a low diversity as indicated by low species richness, which is rather characteristic for the montane forest of West Java. Low similarity indices with other various plots in the park indicate that floristically it also cannot be regarded as a typical montane forest of the Mount Halimun National Park. Although there have been a number of vegetation studies in the park, further studies are still needed, in particular at the elevation below 1,000 m and secondary forests in order to understand the vegetation of the park better and to provide more complete data for managing the park.
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