Journal of Environmental Treatment Techniques

2020, Volume 8, Issue 3, Pages: 1220-1224

J. Environ. Treat. Tech.

ISSN: 2309-1185

Journal web link: http://www.jett.dormaj.com

https://doi.org/ 10.47277/8(3)1224

Diversity of Molluscs (Gastropod And Bivalve) In

Mangrove Ecosystem of Oransbari District, South

Manokwari Regency, West Papua Province,

Indonesia

2,3

2,4*

Markus Waran , Marlon I. Aipassa , Jacob Manusawai , Anton S. Sinery

PhD student of environmental sciences programs of Papua University

Postgraduate programs of Papua University

Forestry Faculty of Mulawarman University

Environmental Research Centar of Papua University, Indonesia, Amban Manokwari 98313

Received: 07/06/2020

Accepted: 30/07/2020

Published: 27/07/2020

Abstract

In the Oransbari mangrove ecosystem, 13 species of molluscs were identified with 1256 individuals consisting of 9 species of

gastropod and 2 species of bivalve. Dominance index of the identified molluscswas 0.11, with species diversity index of 1.89 (medium

category) and species evenness index of 0.76 (high category).

Keywords: Diversity, Molluscs, Gastropod, Bivalve, Mangrove Ecosystem, South Manokwari

Introduction¹

through the revised of West Papua spatial planning document

(

1). According to (1), West Papua currently has 39% of marine

Mangrove in South Manokwari Regency is one of the

protected area and 55-60 % of terrestrial protected area, in the

revised of West Papua spatial planning 2013-2033.

potential mangrove ecosystems that could be intensively

managed by local government to support the sustainable

development goals. This is based on change of function of forest

area for development and optimization of the environmental

quality index through efforts to increase the area of protected

areas to 47% (41,691 ha) from the current condition of 46%

Molluscais a group of organisms that play an important role

in ecosystem mangroves, as it is often used as environmental

bioindicator. According to researchers mollusca is the second

most common phyla after Arthropods consisting of

Polyplacophora (chitons), Gastropods (snails), Bivalvia (clams),

Scaphopods (hornshells), Cephalopods (squid or octopus),

Aplacophora and Monoplacophores and Monoplacopora. From

those seven classes, Gastropoda and Bivalvia are considered as

the largest classes of molluscs (2). Both of them play an

important role in ecology (the food chain), as well as in

supporting the economic life of the coastal community.

Mangrove gastropods are detritus-eaters that play a role in

breaking down fresh litter, as well as accelerating the process of

litter decomposition by microorganisms (3). According to (3),

molluscs are beneficial to humans including as a source of

protein, animal feed ingredients, industrial materials, jewelry,

fertilizer materials and medicines. For instance, several species

of molluscs such as Terebralia palustris, Telescopium

telescopium, Cerithidea obtusa (3). Moroever, some speciessuch

as Anadara granosa, Gelonia erosa, Anadara pilula, Gelonia

(41,306 ha). Besides, as an effort to maintain mangrove

ecosystem related to its function as a buffer against abrasion and

tsunami, the habitat of various types of aquatic biota, mangrove

also plays an important role in community livelihood through

the utilization of aquatic biota, especially fish, crabs, shrimp and

mollusks.

Management of mangrove ecosystem in Oransbari district is

applied through the intensive management plan of the Oransbari

mangrove forest area in order to particularly support the area of

West Papua mangrove forests 4.81% (4,791.29 km ) of total

area as well as to maintain in general the Indonesia mangrove

forests which reaches 3.2 million ha (22,4%) of world. The

target plan is ongoing with the commitment of maintaining 39%

of marine protected area and 57% of terrestrial protected area

expansa,

Isognomon

ephippium,

Faunus

ater

and

Corresponding author: Anton S. Sinery, (a) Postgraduate

programs of Papua University and (b) Environmental Research

Centar of Papua University, Indonesia, Amban Manokwari

Cerithideopsilla cingulata are generally consumed by coastal

communities, especially in the regions of Papua and West

Papua.

8313.

Mobile

phone:

085244308802.

E-mail:

Oransbari mangrove ecosystem with total area of 384,9 ha is

anton_sineri@yahoo.com

220

Journal of Environmental Treatment Techniques

2020, Volume 8, Issue 3, Pages: 1220-1224

one of the mangroves in the region that has potential flora, fauna

and ecosystem services that are worth to be developed. One of

mangrove potencies is molluscs species, especially gastropod

and bivalve which have ecological and economic importance for

the ecosystem and coastal community. According to interview

and field observation, there are several types of molluscs in this

region, but they are not yet scientifically identified. Therefore,

the research aims to identify types of molluscs particularly

species of gastropod and bivalve in Oransbari mangrove

ecosystem.

species;

number of individuals of all species.

Dominationisa community characteristic that shows the

abundanceof species in a region (Odum, 1971 in 13). The

criteria of domination index according to Odum (1993) are: 0

<C <0.5 = Thereare no dominant species; 0.5> C> 1 = Thereare

dominant species. To determine the diversity of mollusca as an

indicator of habitat, species index diversity (H) according to

Shanon and Wiener (1949) in (13) was used with the equation:





















H  





N 

Material dan Methods

This research was conducted in mangrove ecosystem of

Oransbari district, South Manokwari Regency, West Papua

Province, Indonesia. The study was done for two months from

January to February 2020. The equipments used consisted of

GPS (Global Positioning System), levers, plastics, collection

bottles, tweezers, digital camera, vernier caliper, surgical boards,

gauges, raffia and stationery. The materials used were label

paper and alcohol 70%and formalin.

The research was using descriptive method with observation

techniques. The observation station was determined using

purposive sampling which isconsidering the zonation of

mangrove vegetation. The Oransbari mangrove ecosystem

Note: H = diversity index (Shanon-weinner index); ni =

Number of individuals of a species, N = Number of individuals

of all species. Shanon and Wiener (1949) in (13), species

diversity was considered high if the species diversity index was

more than three (H≥3), medium if species diversity index was

between one to three (1 <H <3) and low if species diversity

index was less than one (H <1). The evenness of species of

mollusca at the study site was analyzed using the index of

evenness (e), according to (13) as follows:

e 



hasspecies relatively similar with

forest width of

LogS Hmax

approximately 120-1000 m. Consideringthe condition, the

observation sites (sampling stations) was determined in one

transect 120 m long dominated by Sonneratia sp, Rhizophora sp,

Avicennia sp, Bruguera gymnorhiza. Each site had four

obsevation plots with size of 10 m x 10 m.

Hmax  2 lns

Note: e = species evenness index; H = species diversity

index; S = Number of species. Evennessindex according to

Krebs (1985) in (14) ranged from 0-1, where: 0.6-1 = high

species evenness; 0.4 <e <0.6 = moderate species evenness; 0–

04 = low species evenness.

The main variables observed were morphological characters

of mollusca (gastropod and bivalve) in form of color, body size

(length, width, diameter expressed in cm) in order to determine

the species and number of individuals. Moreover, general

condition of study site was documented. Collecting samplesof

molluscs (gastropod and bivalve) weredone at low tide and in

sunny day. The samples on substrate and attached to mangrove

roots (inside the plot) were taken entirely. The collected samples

thus were preserved using alcohol 70% and put into specimen

box. Furthermore,the samples were identified using the journal

3 Results and Discussion

.1 Species Composition

Based on the identification of the morphological

characteristics of the mollusca body, 13 species of molluscs

were identified, consisting of 7 families and 9 species of

gastropod, 2 families and 4 species of bivalve (Table 1). The

result as shown in Table 1 showed that the composition of

molluscsfound in Oransbari mangrove ecosystem was smaller

compared to (15) there were 30 species found in Tanjung Jara,

Terengganu beach, Peninsular Malaysia, 11 species were found

in Northeast Algeria (16), 15 species were found in the

mangrove ecosystem of Lubuk Kertang village, North Sumatra

(17), 65 species were found in the waters of Ambon Island,

Indonesia (18), (12) which identified 75 species of gastropod

and 19 species of bivalve in South Biak Papua. (11) found 14

species of gastropod and 1 species of bivalve in mangrove forets

of Dedap Village, Tasikputripuyu Kepulauan Meranti regency in

Riau Province. (10) recorded 15 species of gastropod in TPI

Parit 7, Tungkal I village, West Tanjung Jabung and 16 species

of gastropod in the mangrove forests of Teluk Awur Jepara (19),

(

4), (5), (6), (7), (8), (9), (10), (11), (12). The collected data were

analyzed qualitatively and quantitatively based on each

parameter and therefore presented in tables and figures (charts,

graphs and photographs). To determine the abundance of species

in the area, the equation was used as follows:

A 

Note: A = Abundance (number of individual / 20m2); xi =

number of individuals; ni

= Number of squares. The

concentration of individual species of mollusca wasdetermined

usingindex of domination (C) (Simpson, (1949) in (13) as

followed:

(

20) reported 33 species of gastropod in the mangrove

ecosystem in the Gugus Pari Island, and 29 species of gastropod

in the mangrove forest area of Segara Anakan Cilacap (21).

Many speciesof gastropod were found in those studies due to the

wider research location and longer sampling time. While in this

research, the location of the research was small, the sampling





ni 



C  

N 

Note: C = index of dominance; ni = number of individuals of

221

Journal of Environmental Treatment Techniques

2020, Volume 8, Issue 3, Pages: 1220-1224

time was limited and many species have been hunted by local

people for consumption purpose.

Table 1: Composition of Molluscs in the Oransbari Mangrove

Ecosystem

Indiv Percent

idual (%)

Family

Species

Gastropod

Neritidae

Terebridae

Nerita articulata, Gould, 1847

Terebralia palustris Linnaeus,

192 15,29

161 12,82

767

Potamididae Cheritidea sp

149 11,86

143 11,39

141 11,23

Figure 1: Domination index (C), diversity index (H) and evenness index

Trochidae

Neritidae

Monodonta sp

Nerita signata, Lamarck, 1822

(e) of molluscs species in the Oransbari mangrove ecosystem

Littorinidae Littoraria scabra Linnaeus, 1758 125 9,95

The result showed that diversity index of mollusca in the

Oransbari mangrove ecosystem was 1.89. The study found

species diversity of sitewas considered in the medium category.

According to (13), species diversity was consideredhigh if the

species diversity index was more than three (H≥3), medium if

species diversityindex was between one to three (1 <H <3) and

low if species diversityindex was less than one (H <1). Based on

these criteria, the diversity of species of mollusca in the

Oransbari mangrove ecosystem area was belong to medium

category. (13) assertedthat a communitywould havehigh species

diversity if the community was composed of many species with

the similarabundance or almost the same. Conversely, if the

community was composed of several species and if only a very

few species were dominant, then the species diversity was low.

In addition, (22) stated that the level of species diversity could

describe the stability of ecosystem, when the diversity of species

in an area is higher, the ecosystem tends to be more stable and

it would develop interaction of species which could involve

transfers energy, competition and more complex division of

space.

Analysis of species evenness level showed that value of

evenness index of mollusca species in Oransbari mangrove

forest was 0.76. (13) stated that the evenness value was

considered high when e ≥ 0.6, moderatewhen e = 0.4 <e ≤0.6

and low when e = 0 <e ≤ 0.4. Based on the criteria, the evenness

index of mollusca in the Oransbari mangrove forest