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40.7 individuals/m
2
respectively. Other dominant
species are broadleaves speciesofAsystasiagangetica
(L.) T. Anderson, namely 28.8 individuals/m
2
, 17.2
individuals/m
2
, and 18.8 individuals/m
2
,
respectively. Other dominantspecies
arePaspalumconjugatum Berg with a density of 15.0
individual/m
2
, 24.9 individual/m
2
, 30.9
individual/m
2
respectively.
N. biserrata is a fernspecies originating from
Tropical Asia (Old World Tropics) (Burkill, 1966).
This plant has a smooth and scaly leaf surface, 2 cm
length and width of 1 cm. The leaf shape pushes and
the end is split, while the leaf edge is serrated. The
size of the fertile leaves (spore) is larger than the
sterile leaves (nospore). In Indonesia, N. biserrata is
easy to find in plantations, especially in oil palm.
This plant is easy to adapt because epiphytic, and it
has dry resistance and creeping rhizome (Putri,
2012).N. biserrata can also be found in highlands,
dry areas such as deserts, watery or swampy areas
and shady forests (Efendi, 2009).
BesidesN. biserrata, the other dominant
vegetation, is Asystasiagangetica (L.) T. Anderson.
A. gangeticais a perennial plant originating from
Africa, Arabia (Adetula, 2004), India (Holm et al.,
1977) and first introduced to Malaysia in 1876 and
1923 as ornamental plants (Wiart, 2000). In contrast
to N. biserrata, A. gangeticais invasive weeds in oil
palm plantationdue to its ability to produce large
quantities of seeds, which are estimated 27 million
seeds per hectare (Priwiratama, 2011), catapulted as
far as 6 m (Adetula, 2004), and easy to germinate
that itcan quickly dominate the land. New plants can
also grow from the stem base when touching the
ground (Priwiratama, 2011), and within 6 weeks
already flowering and produce seeds (Adetula,
2004).
Paspalumconjugatum is a weed-grass found in
plantation, and as animportant weed on some crops
(Adriadiet al., 2012).P. conjugatum is perennial
grass, spread rapidly above ground level with a
distance of 5-15 cm, each plant produces roots and
leaf buds with a height up to 30 cm. Such grass has
a soft, deep green bar with a width of 1 cm and a
length up to 20 cm, hairy on both surfaces, and
wrinkled edges. There is a ligula, that is a very short
membrane with a length of less than 1 mm with a
long rim of hair behind it. According to Holm et al.
(Holm et al. 1977), an individual P. conjugatum can
produce 1,500 seeds that spread easily and
germinate immediately. The original habitat is
forests and forest edges in humid tropics, but now
found in many plantations and other annual
croplands. P. conjugatumis grown well in full
sunlight and tolerant to partial shade, as well as
tolerance to poor acid soils (Cabi, 2018).
The data analysis showsvegetation structure
under oil palm stands based on relative density
(KR), relative frequency (FR), relative dominance
(DR), important value index (INP) and Summed
Dominance Ratio (SDR) of the 10 dominant
vegetation types for each year of oil palm(Table 3).
In the 9, 13, and 18 years old of oilpalm
plantation, there are two vegetation types with the
highest SDR values namely
NephrolepisbiserrataKuntze (19.6%, 18.7%, and
25.9%), and Asystasiagangetica (L.) T. Anderson
(16.5%, 9.2%, and 8.9%), respectively.Vegetation
with the lowest SDR values is different from each
age of palmoil. In the 9 year old of oil palm, the
lowest SDR values were Mucunacochinsinensis
(0.1%), while in 13 years old is Hyptisrhomboidea
Mart. and Gal. (0.2%), and 18 years old is
Urenalobata L. and Passiflorafoetida L. (0.3%).
This shows that N. biserrata and A. gangetica are
most dominant among other species in this oil palm
plantation.
In the three different ages, N. biserrata and A.
gangeticahas higher relative density, relative
frequencies and relatively dominance than other
vegetation, because the twospecies have the largest
number of individuals and always found in every
plot and its wide spread. In turn, N. biserrata and A.
gangetica have the highest INP and SDR.
BesidesN. biserrata and A. gangetica, other
vegetations that havehigh relative density, relative
frequencies and relatively dominance in each of oil
palm plantationareS. indica., P. conjugatum, A.
compressus, S. spontaneum, S. plicata, A. cuneatum,
A. tenerum, and E. hirtaat 9yearold oil palm
plantation; S. indica, O. compositus, A. compressus,
B. mutica, S. spontaneum, E. hirta, andC. hirtaat 13
years old; and P. conjugatum, S. indica, C.
oxyphyllum, S. spontaneum, C. hirta, A. compressus,
O. nodosa, andO. barrelieriat 18 yearsold.
Shannon diversity index is divided into several
criteria, namely H> 3.0 (very high), H = 1.5-3.0
(high), H = 1.0-1.5 (moderate), and H <1 (low)
(Margurran, 2004). Accordingly, the biodiversity
index (H') in 18 and 13 years old of oil palm
plantationfor all weeds is 3.1 and 3.2 (very high),
and 2.9 (high) in 9 years old. Adriadi et al. (2012)
confirm such a finding for oil palmplantation in
Kilangan, MuaroBulian, Batang Hari which shows
the index of biodiversityis also high, ie 3.14.
Thebiodiversity value of an organism depends on the
large number of individuals found in the community
(Odum, 1996).
ICMR 2018 - International Conference on Multidisciplinary Research
256