Abrasion impact towards green turtle Chelonia mydas ... · Green turtles (Chelonia mydas) are...

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( Received 29 June 2020; Accepted 20 July 2020; Date of Publication 21 July 2020 )

WSN 147 (2020) 124-139 EISSN 2392-2192

Abrasion impact towards green turtle Chelonia mydas (Linnaeus, 1758) nesting areas in Sindangkerta, Tasikmalaya Regency, West Java,

Indonesia

Rifki A. Mustaqim*, Sunarto, Mega L. Syamsuddin, Ibnu Faizal

Department of Marine, Faculty of Fisheries and Marine Science, Universitas Padjadjaran,

Jatinangor, Sumedang 45363, West Java, Indonesia

*E-mail address: [email protected]

ABSTRACT

Green turtles (Chelonia mydas) are marine reptilians that have habitats in coastal areas to lay

eggs. Abrasion is a phenomenon of beach erosion caused by waves and ocean currents which can cause

damage to the coast. The purpose of this research is to analyze the impact of abrasion on green turtle’s

nesting areas (Chelonia mydas). The research was conducted in the coasts of Sindangkerta, Tasikmalaya

Regency, West Java, from December 2019 to January 2020. The method used in this research is

observation and survey method, and the data are analyzed comparatively and descriptively. The data

used consist of satellite imagery, tide, turtle’s landing, and the characteristics of turtle nesting areas in

Sindangkerta coast in the year 1999, 2013, and 2019. The results showed that abrasion changes the

condition of the Green Turtle (Chelonia mydas) nesting areas which led to a 40.09 m decrease in beach

width, 2.04˚ decrease in beach slope, 15.51% increase in sand (fine-medium), and a loss of several

coastal vegetation species.

Keywords: Abrasion, Green Turtle, Nesting Area, Satellite Imagery, Coastline, Sindangkerta, Chelonia

mydas

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World Scientific News 147 (2020) 124-139

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1. INTRODUCTION

Turtles are animals that belong to a type of marine reptile that spend most of their life in

the ocean and only come ashore to lay eggs. Indonesia has 6 of 7 turtle species found in the

world, and Indonesia has one of the largest habitats of Green Turtle (Chelonia mydas) nesting

areas [1]. Internationally, the Green Turtle (Chelonia mydas) belongs to the Endangered Species

group on the IUCN Red List, meaning that the species will soon be at risk of extinction. On the

CITES, Green Turtle (Chelonia mydas) is categorized in Appendix I, meaning that the species

is prohibited in all forms of international trade. Indonesia itself has established protection for

all types of turtles including the Green Turtle (Chelonia mydas) through the Government

Regulation No. 7 of 1999 concerning Preservation of Plants and Animals.

One of the areas used as a landing ground and nesting area for green turtles is the

Sindangkerta Coastal Region of Tasikmalaya Regency, West Java. Based on data from the

Sindangkerta Region Conservation Resort in 2008, 103 green turtles were found ashore and

laying 10,122 eggs, the highest number of turtles and eggs since 2004. With an area of 90

hectares, Sindangkerta Beach has been designated as Sindangkerta Wildlife Reserve.

It is located in the southern coast which is directly adjacent to the Indian Ocean.

Therefore, this region is often hit by high waves from the open ocean [2,3] Wave heights can

cause longshore and perpendicular currents that lead to a deficit in coastal materials which

causes abrasion [4, 5].

The abrasion phenomenon is one of the major threats to green turtles’ habitats. It is a

dominant factor which influence the coastline greatly, such as a change in its width [4].

Abrasion can also change the beach slope, making it steeper, and change the beach sand

structure [6]. It can cause degradation or loss of coastal vegetations [7] which affects the beach

slope. Turtles tend to choose nesting sites with slopes less than 30° [8], The appropriate type of

sand for turtles to lay eggs is fine-medium sand with a percentage of 90% [9]. Coastal vegetation

is one of the requirements for turtles to choose a beach as their spawning location because the

presence of vegetation in a nesting area will provide them with comfort as they lay eggs [7-9].

Based on this background, a research needs to be conducted to analyze the impact of

abrasion on green turtles’ nesting areas in the coastal regions of Sindangkerta, Tasikmalaya

Regency so that the results of this research can be used to help manage coastal areas, especially

the Green Turtle (Chelonia mydas) nesting areas.

2. MATERIALS AND METHODS

2. 1. Study Area

The research was located in the Sindangkerta Coastal Region in Cipatujah District of

Tasikmalaya Regency, West Java, Indonesia. The coordinates are 7° 40' 13.5"- 7° 10' 52.4" S

and 108° 3' 30"- 108° 5’ 00" E. The data collection station was divided into 6 (six) stations

which were determined based on the area that is often used as a landing ground for turtles, either

to lay eggs or simply to rest.

Sindangkerta Coastal Region is directly adjacent to the Leuweung Sancang Nature

Reserve which is located in the west, to Ciawitali District in the north, Cijulang District in the

east, and South Java Sea in the south (Figure 1).


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Figure 1. Map of the Research Location in Sindangkerta; Katapang (Station 1), Tegal Sereh

(Station 2), Panarikan (Station 3), Pamoekan (Station 4), Karang Handap (Station 5), and

Palawah Butun (Station 6).

2. 2. Data and Methods

This research was conducted from December 2019 to January 2020. The data used in this

research were primary data and secondary data. Primary data consisted of: the width and slope

of the beach, large grains of sand, types of vegetation, and other biophysical parameters of the

Green Turtle nesting area in the Sindangkerta Coastal Region. Secondary data consisted of:

Landsat 7 ETM + digital image in 1999, Landsat 8 ETM + digital image in 2013 and 2019 in

the Sindangkerta region, Tasikmalaya Regency with a spatial resolution of 30 meters, as well

as data on the number of Green Turtles that came in 1999, 2013 and 2019.

Beach width was measured using a rolling meter by drawing a perpendicular line from

the highest tide to the outermost vegetation limit [10]. Each station was measured three times

in an area that represented its coastal width. The beach slope was measured using the Pythagoras

principle. Measurements were made using a 5 m scale rope to measure the width of the beach,

a stick of 1.5 m to get the height data and water which passed to maintain the straightness of

the scale rope. The measurement projection started from the outermost vegetation to the first

part of the beach which gets wet due to waves by projecting an extreme point perpendicular to

the coast [11]. The beach slope was obtained by the formula:

𝜶 = 𝑎𝑟𝑐 tan H

D


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Notes:

𝜶 = Beach slope angle (°)

H = Total beach height (a+b+c+d)

D = Total beach flat distance (1+2+3+4).

The beach slope angle was then identified based on [12] (Table 1.).

Table 1. Classification of Beach Slope Level.

Slope (°) Characteristic

<1 Flat to Almost Flat

1–3 Gently Sloping

3–6 Sloping

6–9 Moderately Steep

9–25 Steep

25–65 Very Steep

>65 Extremely Steep

The size of the sand grains was identified by processing the sand sample in the sieve

shaker. Samples were processed and analyzed using the sand fraction method [11]. Processing

results were then classified according to the USDA sand grains classification standard [13]

(Table 2).

Table 2. Standard Classification of Sand Grains.

Diameter (mm) Fraction

>0,02 Gravel

0,05–2 Sand

1–2 Very Coarse Sand

0,5–1 Coarse Sand

0,25–0,5 Medium Sand

0,1–0,25 Fine Sand

0,05–0,1 Very Fine Sand

0,002–0,05 Silt

<0,002 Clay


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Beach vegetation was identified based on the species name of each research station. The

vegetations that were identified were the ones in the outermost region or vegetations that border

the coast of the Green Turtle (Chelonia mydas) nesting areas. The identification results were

then analyzed based on what kind of vegetation grows in the nesting area.

Satellite image data was obtained from an image data provider website

https://glovis.usgs.gov. Image data processing was performed using ArcGIS 10.3. The first step

in processing this data was a geometric correction, which was done by placing pixels back in

such a way that on the transformed digital images, a picture of objects on the earth’s surface

which is recorded by sensors [14].

The second stage was color composite and image cutting to distinguish several objects in

each band before using a combination of Red Green Blue (RGB) on the object. Image data

cutting was done to limit the research area. The third stage was to sharpen the image to facilitate

visual interpretations through increased color and light contrast [15]. Image data analysis was

performed on the DSAS (Digital Shoreline Analysis System) software by calculating the Net

Shoreline Movement (NSM) to determine changes in distance between the longest and most

recent shoreline [16]. To find out the area of abrasion/accretion, shapefile was made in the area.

Next, the Calculate Geometry tool was chosen to calculate the area with units of 'square meters’

(sq m) [17]. The final step was the map presentation to adjust the projection and page layout by

adding coordinates, scale, wind direction, title, text, object, and map legend [15].

Data on the landing of green turtles in the Sindangkerta Coastal Region was obtained

from the Conservation Resort Region XX Pangandaran. Data from abrasion identification

results and characteristics of the green turtle nesting areas were analyzed comparatively against

the conditions before the abrasion phenomena to discover the impacts caused by abrasion

towards the nesting areas.

3. RESULT AND DISCUSSION

3. 1. Physical & Biology Characteristics

The Sindangkerta Coastal Region has a sand temperature and light intensity that is

relatively suitable for turtle nesting. The average sand temperature measured at depths of 40-

50 cm is 29.93 °C. Out of 6 stations, only 1 was identified to have a temperature above 32 °C.

The ideal temperature for the turtle nesting area ranges from 23-32 °C [18, 19]. The

measurement results of light intensity at night has an average of 0.22 Lux. Appropriate light

intensity for turtle nesting area ranges from 0-1 Lux. Based on field measurements, all stations

have light intensity below 1 Lux, suitable for turtle nesting areas [20].

Another parameter measured was the tides. Sindangkerta Coastal Region has semi-

diurnal tides that consist of two high tides and two low tides each day, with the highest tide of

1.002 meters and the lowest tide of -0.913 meters in October (Figure. 10). In general, the highest

tides occur at 2:00 a.m. GMT+7 and 2:00 p.m. GMT+7, while the lowest tides occur at 09.00

GMT+7 and 20.00 GMT+7. The highest tide is useful to determine the width of the beach and

predicting the turtle’s time arrival.

Based on the type of vegetation in the area, some vegetations were lost from 1999 to

2013. This occured due to abrasion, or differences in the research locations conducted in 1999

and 2013, which can cause a collapse or loss of coastal vegetations where turtles lay eggs [21].


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Meanwhile, the new vegetations were thought to exist to planting, both by the community

and the party's manager or because there were new seeds carried by the river which flowed into

the waters of the Sindangkerta Coastal Region of Tasikmalaya Regency.

Figure 2. Graphic of tidal average at Sindangkerta Coastal Region in 2019 measured at the

Pamayangsari tidal observation station.

Table 3. Comparison of Vegetation Types.

Year

Vegetation Types 1999 2013 2019

Barringtonia asiatica

Calophyllum inophyllum

Cerbera manghas

Crinum asiaticum Linn

Cycas pectinata

Ficus septica

Gonocaryum macrophyllum

Hibiscus tiliaceus

Ipomea pes-caprae

-1,5

-1

-0,5

0

0,5

1

1,50

:00

20:0

01

6:0

01

2:0

08

:00

4:0

00

:00

20:0

01

6:0

01

2:0

08

:00

4:0

00

:00

20:0

01

6:0

01

2:0

08

:00

4:0

00

:00

20:0

01

6:0

01

2:0

08

:00

4:0

00

:00

20:0

01

6:0

01

2:0

08

:00

4:0

00

:00

20:0

01

5:0

01

1:0

07

:00

3:0

02

3:0

01

9:0

0

Sea

Su

rface

Ele

vati

on

(m

)

Time (WIB)


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Lophatherum gracile

Morinda citrifolia

Pandanus tectorius

Pongamia pinnata

Scaevola teccada

Spinifex Littoreus

Terminalia cattapa

Tournefortia orgentea

Comparison of coastal vegetation types in 1999, 2013 and 2019 shows an increasing

number of vegetation types. For example, Calophyllum inophyllum, Crinum asiaticum Linn,

Ipomea pes-caprae, Pongamia pinnata, Scaevola teccada and Spinifex Littoreus were found in

2013 but not in 1999. Some vegetations were not found in 2013 but appeared in 1999, such

such as Ficus septica, Gonocaryum macrophyllum, Morinda citrifolia, and Tournefortia

orgentea. In 2019, the number of vegetation types increased with the discovery of Cerbera

manghas, Cycas pectinata, Lopatherum gracile, and Morinda citrifolia. However, there are

vegetations that were discovered in 2013 but not in 2019, such as Scaevola teccada and Spinifex

Littoreus (Table 3.).

3. 2. Beach Width and Slope

The Sindangkerta Coastal Region has a beach length of 3.4 km. Based on field

measurements, the average width of Sindangkerta Coastal Region is 29.25 meters. Three

stations have a beach width of more than 30 meters which are suitable for turtle nesting areas,

i.e. Station 1, Station 2, and Station 3; the other three stations have a beach width of less than

30 meters. The short width of a beach is caused by the destruction of coral reef ecosystems that

are triggered by iron sand mining activities in the area. Sand excavation or coral mining causes

larger waves to hit beaches (due to the loss of dampers), causing damage [22].

Based on DSAS (Digital Shoreline Movement) analysis, abrasion in 1999 and 2013

occurred at Station 1, Station 2, Station 3, Station 4, and Station 6. According to the beach width

data on the Sindangkerta Coastal Region of Tasikmalaya Regency, in 1999 and 2013 (Figure

4.) the beach width seemed to retreat or decrease from 52 to 17.02 meters at Katapang Station,

52.75 to 6.21 meters at Tegal Sereh Station, 45.25 to 6.44 meters at Panarikan Station, and

36.50 to 3.45 meters at Pamoekan Station.

At Karang Handap Station and Palawah Butun Station, there was no beach width data in

1999 so changes were not identified. Abrasion process is the dominant factor affecting shoreline

changes, which influence the width of the beach [23]. Beach widths in 2019 are not compared

to the ones in 2013 and 1999 because based on the DSAS (Digital Shoreline Movement)

analysis from 2013 and 2019, no abrasion occured. In 2019, the width tend to increase which

indicates accretion.


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Figure 3. Graphic of Beach Width Comparison

The beach slope in the Sindangkerta Coastal Region is divided into the followng criteria:

gently sloping with an angle of 1-3°, sloping with an angle of 3-6°, and moderately steep with

an angle of 6-9°. The average beach slope is 4.16°. Based on the coastal slope measurements,

all stations have a suitable slope for turtle nesting areas, which is <30°. Data in 1999 showed

that the slope of the beach tend to be steep, amounting to 19.90° at Katapang Station, 12.75° at

Tegal Sereh Station, 12.40° at Panarikan Station, and 13.25° at Pamoekan Station, whereas the

beach slope at Karang Handap Station and Pamoekan Station were not measured. In 1999 and

2013, there are changes in beach slope which tend to be sloping, which was 6.98° at Katapang

station and 2.29° at Tegal Sereh Station, whereas at Panarik Station and Pamokan Station, it

tend to be steep with a slope of 17.22° at Panarikan Station and 21.80° at Pamoekan Station

(Figure 4).

The slope of the beach is affected by beach scarp. Abrasion can form 2 types of beach

scarp i.e. beach scarp that forms between the intertidal zone and the outer boundary of coastal

vegetation and beach scarp that forms at the tip of the supratidal zone or the outer coastal

vegetation boundary [24]. Changes in beach slope (tend to be sloping) from 1999 and 2013

were caused by the beach scarp location which was on the coastal vegetation outer boundary,

while changes in the coastal slope which tend to become steep were due to the beach scarp

location that was between the intertidal zone and the outermost vegetation boundary.

The occurrence of abrasion was only detected in 1999 and 2013, therefore the beach slope

data in 2019 were not compared to the ones in 2013. Beach slope data from 2013 to 2019 show

changes that tend to be sloping at each research station.

52 52,75

45,25

36,5

0 0

17,02

6,21 6,443,45 3,22 2,86

37

46 45,5

28,25

8,75 10

0

10

20

30

40

50

60

Katapang Tegal Sereh Panarikan Pamoekan Karang

Handap

Palawah Butun

Bea

ch W

idth

(cm

)

Station

1999 2013 2019


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Figure 4. Graphic of Beach Slope Comparison

3. 3. Sediment Type

Based on the KUMMOD-SEL analysis, the sediment types that were identified were sand

with a brownish-black color and slight gravel sand with a whitish black color. The average sand

(fine-medium) percentage was 88.72%. Three stations have a sand (fine-medium) percentage

above 90% which are suitable for turtle nesting area, i.e. Station 1, Station 2 and Station 3. The

remaining three stations have a sand percentage below 90%. The sand size distribution is

influenced by material sources, topography, and sediment transport mechanism [25,26]. Coarse

sand in the Sindangkerta Coastal Region comes from sediment transport which originate from

the weathering of chunks of coral due to mining activities of iron sand that are carried to the

beach.

Data comparison on sand sediments from 1999 to 2013 showed an increase in sand (fine-

medium) percentage with an increasing range of 15.76% - 20.95%. The abrasion phenomenon

that occurred from 1999 to 2013 showed a change in the sand structure; it became smoother.

Form 2013 to 2019, the sand percentage tend to decrease (Figure 5).

Increased percentage of sand (moderate fine) indicates a change in the composition of the

sedimentary structure. Areas affected by abrasion will be dominated by fine sand and silt

sediment, while accretion-affected areas will be dominated by sand and a little gravel [27].

19,9

12,75 12,413,25

0 0

6,98

2,29

17,22

21,8

17,74

9,09

2,75 2,24 2,39

4,76

6,935,78

0

5

10

15

20

25


Handap

Palawah Butun

Bea

ch S

lop

e (°)

Station

1999 2013 2019


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Figure 5. Graphic of Sand Percentage (Fine-medium) Comparison

3. 4. Effect of Nesting Area on the Number of Landing

Several factors that affect turtle landings are the physical and biological characteristics of

the beach, which include beach width, beach slope, sand percentage, sand temperature, light

intensity, food availability and beach vegetation [28]. Data on turtle landings in the

Sindangkerta Coastal Region shows fluctuating numbers, with all of them being green turtles

(Chelonia mydas). The number of turtles that landed in 1999 was 111, while in 2013 the number

dropped dramatically to 25 and increased again in 2019 to 54 (Table 4).

Table 4. Comparison between the Number of Turtles Landing and

the Habitat Conditions for Green Turtle (Chelonia mydas) Nesting Area.

Year Turtle

Landed

Beach Width

(m) Beach Slope (°)

Percentage of Sand

(Fine-medium) (%)

1999 111 46,62 14,57 78,70

2013 25 6,53 12,53 94,21

2019 54 29,25 4,14 88,72

78,7 78,7 78,7 78,7

0 0

99,5 99,65 99,694,46 92,94

79,11

98,193,62 90,71

91,56

79,6878,66

0

20

40

60

80

100

120


Handap

Palawah Butun

San

d P

erce

nta

ge

(%)

Station

1999 2013 2019


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The characteristics of Green Turtle (Chelonia mydas) nesting areas show that in 1999, the

physical and biological characteristics were qualified as nesting areas which led to a high

number of turtle landings. Unfortunately in 2013, there was a decline due to abrasion which

made the nesting area conditions not ideal. In addition to changes in the nesting area conditions,

the rise of iron sand mining around the coasts from 2000 to 2011 also caused environmental

degradation, such as loss of land area and murky waters [29].

The number of turtle landings increased again in 2019, 54 of which were Green Turtles

(Chelonia mydas). The increase in the number of turtle landings was due to a more idealized

condition of the nesting areas. The field results show that the physical and biological conditions

at the site in 2019 were ideal where out of 6 research stations, only 2 stations did not meet the

ideal beach width for turtle nesting areas.

3. 5. Abrasion Identification

The abrasion and accretion phenomenon can be identified visually through the

intersection between the coastline in 1999 (blue line) and the coastline in 2013 (yellow line)

(Figure 6). The analysis results of the abrasion area in the Sindangkerta Coastal Region from

1999 to 2013 were 93,777.11 𝑚², while the accretion area was 11,020.03 𝑚².

Figure 6. Map of the Abrasion and Accretion Detection in 1999-2013

The map identification of abrasion and accretion in the Sindangkerta Coastal Area in

1999-2013 shows the occurrence of abrasion and accretion at each research station. The highest


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abrasion with an NSM (Net Shoreline Movement) value of -118.29 or an abrasion length of

118.29 meters was found in Station 2 (Tegal Sereh) which is indicated by a green line on the

map. The lowest abrasion with an NSM value of -3.41 or an abrasion length of 3.41 meters was

found in Station 3 (Panarikan) which is indicated by a light blue line on the map. The largest

accretion was identified based on the NSM value of 53.24 or an accretion length of 53.24 meters

in Station 3 (Panarikan) which is indicated by a pink line on the map. The smallest accretion

identified was at Station 5 (Karang Handap) with an NSM value of 4.61 or an accretion length

of 4.61m indicated by a purple line on the map.

The analysis results of abrasion area (93,777.11 𝑚²) indicate that in 1999 to 2013, the

Sindangkerta Coastal Region tend to experience abrasion. This finding is in accordance with

the highest abrasion length which is 118.29 meters; more than the highest accretion length

(53.24 m). The factor that caused the dominancy of abrasion during 1999 to 2013 was the

presence of sand mining activities throughout the years. Sand mining caused environmental

degradation such as loss of land area and water turbidity [29]. Sand mining in Sindangkerta

Coastal Region began from 2000 to 2011.

Mapping of abrasion and accretion in the Sindangkerta Coastal Region in 2013-2019 was

done by using coastline data from Landsat 8 ETM + in 2013 and 2019 which were processed

with ArcGis 10.3. The results of the coastline visualization show that there was no abrasion.

This is proven by the absence of intersection line between the coastline of 2013 (yellow line)

and the coastline of 2019 (red line) (Figure 7) The coastline of 2019 tends to advance towards

the ocean which shows accretion. The accretion area was calculated by the Calculating

Geometry tool and the result is 96,828.11 𝑚².

Figure 7. Map of the Abrasion and Accretion Detection in 2013-2019


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The largest identified accretion based on the NSM value of 106.4 or an accretion length

of 106.4 meters was found in Station 1 (Katapang) which is indicated by a pink line on the map.

The smallest accretion was identified in Station 2 (Tegal Sereh) with an NSM value of 4.79 or

an accretion length of 4.79 meters indicated by a purple line on the map.

The analysis results of the map identification for abrasion and accretion in 2013-2019

showed the occurrence of accretion, but no abrasion. This is allegedly because there were no

sand mining activities in the area, which was previously a dominant factor in the occurrence of

abrasion [30]. Meanwhile, the sedimentation process which originated from 4 rivers [31] flows

to the Sindangkerta Coastal Region. This was one of the dominant factors in accretion.

3. 6. Abrasion Impact on the Number of Landing

Based on the impact analysis of abrasion from 1999 to 2013, it is known that abrasion

caused the beach width to decrease by 40.09 meters. As the width decreased, so did the number

of turtle landings. This is because the turtles choose nest locations that is far from the highest

tide. The farther the nest is from the highest tide, the greater the hatch rate of the green turtles

(Chelonia mydas) [32].

Abrasion also caused a decrease in beach slope by 2.04°, and the number of turtle landings

was influenced by it. On a slope of 4-6°, the number of turtle landings decreased but on a slope

of 13-15°, the number of turtle landings increased. This is because in this range, the turtles can

reach the nest easily and prevent the nest from absorbing seawater. However, beaches that are

too sloppy are risking the nest to be exposed to seawater absorption. Beach with slopes above

6° is a factor that determines the success of spawning [33].

Abrasion also changed the sand (fine-medium) percentage by 15.51%. Changes in the

sand percentage do not affect turtle landings as long as the width and slope of the beach is still

ideal. This is because turtles will return to the same beach where they are born, provided that

the beach width and slope are suitable [34]. Beach width and beach slope have a greater

influence on the suitability of green turtle (Chelonia mydas) [35] nesting areas with a value of

14%, where as sand cover is the parameter with the smallest influence with a value of 10%.

Abrasion can also cause a loss of several types of coastal vegetation, but this does not

affect the number of turtle landings as long as one of the vegetations that are often used as a

nest canopy (Calophyllum inophyllum, Pandanus tectorius, Ipomea pes-caprae, or Canavalia

maritime) remains. Coastal vegetations of the tree-type that are often used as shades for green

turtles nesting are Nyamplung (Calophyllum inophyllum) and Thatch Screwpine (Pandanus

tectorius), whereas the shrub-type are Bayhops (Ipomea pes-caprae) and Bay Bean (Canavalia

maritime) [10].

4. CONCLUSIONS

Based on the results and discussions, it can be concluded that an abrasion of 93,777.11

𝑚2 occured in the Sindangkerta Coastal Region of Tasikmalaya Regency in 1999 and 2013,

with the highest abrasion found at Station 2 (Tegal Sereh), which was 118.29 m long, while the

lowest abrasion was at Station 3 (Panarikan), which was 3.41 m long. Abrasion induced changes

in the nesting areas for green turtles (Chelonia mydas) which caused a reduction in beach width

by 40.09 m, a decrease in beach slope by 2.04°, an increase in sand (fine-medium) percentage

by 15.51%, and a loss of several types of coastal vegetations.


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Acknowledgment

The authors are grateful to the Marine Science Department of Universitas Padjadjaran, Sindangkerta Wildlife

Reserve, USGS Global Visualization Viewer (GloVis), and anonymous reviewers who enrich this article.

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