This document discusses the ecology of waters around Java, Indonesia. It aims to compare the health of two coral reefs, examine why a beach is changing after building a pier and planting mangroves, and explain why removing organisms from a food chain can be problematic. Specifically, it analyzes the 1000 islands off Jakarta and the impacts of building infrastructure like piers. It also describes how removing all sea urchins from a reef near a resort damaged the reef's ecology by allowing algae to overgrow the corals.

1. Indonesia’s Coastal Ecology
A Clicker Case
investigating the ecology
of the waters around Java.
Liam Hammer
Department of Science
Global Jaya International School

2. Goals
• To compare the health of two coral reefs
• To examine and hypothesis why a particular
beach is changing (after building a pier and
planting mangroves)
• To explain why removal an organism from a food
chain can be problematic : (Sea Urchins – Tanjung
Lesung experience
• Mangrove replanting ?
• Sea grass ? & Turtles ?

3. Wallace described the island of Java in 1861:
“Taking it as a whole, and surveying it from every
point of view, Java is probably the very finest and
most interesting tropical island in the world.
(Wallace, 1869)

4. Part I – Location of the 1000 Islands
Pulau Seribu or the
thousand islands actually
only number 110. They
are a band of low lying
islands just north of the
coast of Jakarta, up to
80kms away. The
potential of these islands
was recognized in 1979
when they were listed to
become protected.

5. Next to Jakarta, a city of almost 10 million1
people on the island of Java, one of the most
densely populated islands in the world has it’s
challenges. Although the coral islands are not
the best in Indonesia, (those are more likely in
Papua, Bali or Sulawesi), very few countries in
the world have such excellent marine resources
so close to a capital city. (Kvalvagnaes and Halim
1979b)

6. CQ#1 – What sort of potential did the Indonesian
government see in the 1000 islands ?
A. Recreation for foreign and domestic tourism
B. Food benefits for local people
C. Commercial benefits for visiting fisherman
D. Combination for all three

7. CQ#2 – What sort of problems does the 1000
islands face?
A. Poor fishing practices such as dynamite fishing,
overfishing, over exploitation by commercial
fisherman
B. Pollution; sound and waves, trash accumulation
and oil spills, rainwater runoff from residents
and proximity to Jakarta
C. Careless tourism; dumping of rubbish, trample
damage on corals, removal and collection of
coral, shells and organisms for domestic fish
tanks
D. A combination of all three

8. Human Impact : building a pier
Palau Semak Daun, is about a 30 minute boat
ride from Palau Pramuka, the capital island of
the regency. It is a popular day trip destination
for local tourism, as it is uninhabited, with the
exception of a single house for the caretaker.
Prior to 2007

9. 2007 : work has commenced on building a boat pier
to make the island more accessible, currently boats
have to anchor just off the beach.

10. 2008 : the pier and a small shelter
have been completed.

11. 2011 : Four years later the shelter is
looking slightly run down.

12. CQ#3 – What are the main differences between
the two pictures taken four years apart ?
A. The tree is no longer in the picture.
B. The shelter is falling over.
C. The beach has about 5 of metres extra sand.
D. The dark patch of seagrass has moved
forwards.

13. Answer to CQ#3 – What are the main differences
between the two pictures taken four years apart ?
C. The beach has about 4-5 metres of extra sand.
Count the number of pier pylons visible in the
pictures. Notice the seagrass (dark patch) is still in
the same place relative to the shelter and pier, but
is now almost on the edge of the shoreline. The
differences in the tide levels can account for a little
of this, but not all. The tree in the first picture, is
not about 5 metres behind the location of the
photographer.

14. CQ#4 Suggest a reason for the additional sand
on the beach
A. The owner, caretaker of the island or the boat
operators brought some sand from somewhere
else and dumped it here.
B. The building of the pier has resulted in changes
in ocean currents and caused additional sand to
pile up here.
C. Some natural processes are at work here and it
is nothing to worry about.
D. The planting of the mangroves on the other side
of the pier resulted in changes in currents that
cause sand to build up here.

15. CQ#5 – Removing dangerous or annoying
creatures from an ecosystem is a good idea.
A. Yes, people need to be safe to be able to use
the environment.
B. No, it is never a good idea to mess with food
webs.
C. Depends on the situation.

16. Sea Urchins
Sea Urchins (Diadema antillarum) are a
type of echinoderm, they have many
long defensive spines that can easily
pierce human skin and break off into
hands or feet touching them leaving a
painful infected wound. As a result, they
are unpopular with many tourists,
despite being considered a culinary
delicacy in some countries.
Sea Urchins are marine grazers, they eat
algae off the surface of the corals. They
are also are a rather tolerant species
and are able to populate areas that are
more damaged or disturbed than
pristine areas. Thus they tend to be
more common in those areas.

17. CQ#6 – Why are Sea Urchins more
commonly found on degraded coral reefs ?
A. They prefer it there.
B. Less predators.
C. Less competition.
D. They need pollution to survive

18. Tanjung Lesung :
Sea Urchins Management
Tanjung Lesung is an area about 160kms South
West of Jakarta, in the busy Sunda Straights. There
is a large hotel/resort that has a small coral reef
area in a protected bay.
Tourists complained about the sea urchins, so the
management of the resort, which had been facing
hard times due to the fact they were so far away
from Jakarta, hired some divers to spend a week
clearing off every single sea urchin and removing
them from the reef.

19. CQ#7 – Suggest possible results of managements
decision to remove all the sea urchins.
A. Tourism increased because there was no
more sea urchins to sting unwary people.
B. Some larger apex predators starved to death
because of the lack of sea urchins.
C. The sea urchins returned anyway.
D. The coral reef become overrun by algae since
there were no sea urchins to graze on it, and
become damaged as a result.

20. CQ#8 – Removing dangerous or annoying
creatures from an ecosystem is a good idea.
A. Yes, people need to be safe to be able to use
the environment.
B. No, it is never a good idea to mess with food
webs.
C. Depends on the situation.

21. BIBLIOGRAPHY
1. Wallace, A.R. 1869. On the zoological geography of the Malay archipelago. J.Linn. Soc.
London
2. Wallace, A.R. 1869. The Malay archipelado. London: MacMillian.
3. Whitten , Tony. Soeriaatmadja, Roehayat Emon. Afiff, Suraya. 1996.Volume II:The Ecology of
Java and Bali. The Ecology of Indonesian Series, Periplus Editions (HK) Ltd. pgs 345-384, 756
,780-782
4. Setiawati, Indah. After census city plans for 9.5 million The Jakarta Post, Jakarta .08/28/2010
http://www.thejakartapost.com/news/2010/08/28/after-census-city-plans-95-million.html
Date last accessed 28/09/2011.
5. Long Spined Black Sea Urchin Report
21

22. SLIDE CREDITS
• Unless explicitly indicated otherwise below, all images in this Powerpoint Presentation™ are the creation of the case author, L .Hammer.
• Slide 1
– Description: Photo of a Photo of Pulau Semak Daun
– Author: Abbey Budiman
– Source: Global Jaya International School
• Slide 3
– Description: Location of the thousand islands
– Source: Google Earth
– Clearance: Licensed according to terms of Creative Commons Attribution-Share Alike 3.0 Unported.
• Slide 4
– Description: Riparian zone in Grand Teton National Park
– Author: Daniel Mayer
– Source: Wikimedia Commons; link
– Clearance: Licensed according to terms of Creative Commons Attribution-Share Alike 3.0 Unported.
• Slide 9
– Description 1: Photo of Workers building a pier on Pulau Semak Daun
– Author: Liam Hammer
– Source: Global Jaya International School
– Description 2: Photo of boat anchored on the beach of Pulau Semak Daun
– Author: Liam Hammer
– Source: Global Jaya International School
• Slide 10
– Description: Photo of a Photo of Pulau Semak Daun dated 2008
– Author: Liam Hammer
– Source: Global Jaya International School
• Slide 11
– Description: Photo of a Photo of Pulau Semak Daun dated 2010
– Author: Liam Hammer 22
– Source: Global Jaya International School