Ecology Of Avian Community Of Pulau Rambut : Population, Nest Site Distribution, and Foraging Sites
.@
There is only a few herofii-y,of waterbirds in Indonesia, and one of them is
Fulau Rambut Wildlife Sanctuary. Various waterbird species i n a hclge n m b e r
usa the island as their home, despite the fact that the sanctuary is now ~lnder
various thrsat.
The rasearch is a result of an ecologica!.study on the waterbird community
I
5
in the is!and of Pulau Rambut. ~ l m i l astudyhas
r
d&ducte$ in 1989-1562, providing
a good base for a comparative study.
Many institutions and iridividuals have been coptributed in the research.
Funding was generously provided bythe Wagao Natural Environmental Foundation,
$
1
-
q*
Japan, and I atn extremely grateful for their trust and support. Balai KSDA DKI
Jakarta was kindly give me a permission to use the site for my study. I also greatly
thankful to my assistant, Imanuddin, who helped me in all stages of the study,
including the field work, data analysis, and report writing. 7-hanks are also due to
my students, Erni Jumilawati, Dijan Sunar Rukmi and Afif Azhar, who assisted me
in some field works. I would aiso extend my thanks to Warsa Jaya, the forest
ranger (Jagawana), for his help during my field study.
I do hope that the information in this report would serve as an additional
knowledge of the avian community of Pulau Rambut, as well as a source of
information for anyone who need it.
Ani Mardiastuti
Contents
Preface .................................................................................................................
i
I. INTRODUCTIOK
A . Background ..................................................................................................... 1
B . Objectives .......................................................................................................2
II. STUDY AREA DESCRIPTION
A . History and Location ......................................................................................
3
B. Meteorology ...................................................................................................
3
C . Topography .....................................................................................................
5
5
D. Teriestrial Flora and Fauna ...........................................................................
Ill. METHODS
A . Bird Diversity and Population Size ..................................................................8
B. Breeding Season ............................................................................................ 9
C. Nest Site Distribution ..................................................................................... 9
D. Foraging Site ................................................................................................
10
IV. ZESULTS AND DISCUSSION
A . Divsrsity of Waterbirds ................................................................................... 11
..
.............................................................
A . 1. Species Pres2nt and Compos~t~on
11
A.2. Biased in Species Identification ................................................................15
B. Population of Waterbirds ..............................................................................
17
6.1. Population Size of the Waterbird Community ....................................... 17
8.2. Patterns of Population Dynamics .........................................................
18
B.3. Bias in Population Counting .................................................................. 18
C . Assessment of the Diversity and Population Trend: Ten Years Apart
n
...........
21
- ..
v . G i e ~ d l i t yS e a s u ~
1s ........................................................................................LL
E. Nest Site Distribution .................................................................................... 24
. .
F. Idesiii-,g Assoc~ation..................................................................................
27
6 . F ~ r s g i n gArea ...............................................................................................
29
V . UANAGEMEN'T OF PULAU HAFJIGGT
A . Threats and Problem from Outside the Island
1. Deteriorating Condition of Jakarta Bay..................................................... 36
2 . Decressing Size 5f Feeding Ground........................................................ 36
3 . Disturbances from Lccai People............................................................... 36
4 . Disl~rbancefrom visitors ..........................................................................
37
5 . Possible Disiurbacce from Airport Activities ............................................. 37
B. Threats and Problem from inside the island .
1. Reduction of Mangrove Forest .................................................................. 38
2 . Poor Natural Regeneration .......................................................................
38
3 . Possible Competition with the Flying Foxes.............................................. 38
C. Management Implication
1. Predator monitoring ...................................................................................39
2 . Monitoring of Waterbird Species and Population ...................................... 40
3 . Man-made Regenerati~nfor Mangrave Forest ..........................................$0
4 . Control of Visitors ................................................................................41
5 . Improvement of Facilities and Budget ...................................................... 41
LITERATUR CITED ........................................................................................... 42
Appendix 1. Annotated Checklist of Important Birds of Pulau Rambut Wildlife
Sarictuary ..........................................................................................................
44
I. INTRODUCTION
A. Background
Pulau Rambut is a small 45 ha island ("pulau" means island) located in
Jakarta Bay area, Indonesia. This island is a very special site because it has been
used as a breeding site for waterbirds from surrounding areas. Realizing the
importance of the island for waterbird conservatiorl, since 1339 the island has
been gazetted as Nature Reserve. late; on, in 1999 the status of nature reserve
was changed into a Wildlife Sanctuary.
There are thousand of waterbirds nesting on the island, belonging to 14
species. Indonesian government protected most of waterbirds and some of them
(e.g., Milky Stork) has been listed under Birds to Watch 2 and IUCN Red List
Category. A decade ago, Mardiastuti (1992) conducted an intensive study on the
biodiversity and population of waterbirds and provided as baseline data on various
aspect. Some other research that has been conducted during the past ten years
were related to habitat mapping the island usiog Geographical Information System
(Fitriana 1999), breeding biology of the Vilky Stork (Imanuddin 2000), breeding
biology of the Little Egret (Sulistiani 1991), and distribution and diversity of waterbirds
(Mahmud 1992).
The island is located near the Jakarta Metropolitan area, which undergone
a very fast human development. The distance of the island to the nearest coast of
Java is only 3 km. Further, there is also a neighbouring island (1 km apart) inhabited
by large number of human population. Therefore, the island has been receiving a
strong human pressure.
The waterbirds use Pulau Rambut as breeding and roosting site. They have
to go out from the isiand to find food in the wetland of Java mainland. The vast
conversion of wetland into other uses (e.g., housing, rerreation areas, airport,
industrial areas) has been severely reduced the foraging areas of the waterbirds,
and might lead to decrease the population.
There is only a few herofii-y,of waterbirds in Indonesia, and one of them is
Fulau Rambut Wildlife Sanctuary. Various waterbird species i n a hclge n m b e r
usa the island as their home, despite the fact that the sanctuary is now ~lnder
various thrsat.
The rasearch is a result of an ecologica!.study on the waterbird community
I
5
in the is!and of Pulau Rambut. ~ l m i l astudyhas
r
d&ducte$ in 1989-1562, providing
a good base for a comparative study.
Many institutions and iridividuals have been coptributed in the research.
Funding was generously provided bythe Wagao Natural Environmental Foundation,
$
1
-
q*
Japan, and I atn extremely grateful for their trust and support. Balai KSDA DKI
Jakarta was kindly give me a permission to use the site for my study. I also greatly
thankful to my assistant, Imanuddin, who helped me in all stages of the study,
including the field work, data analysis, and report writing. 7-hanks are also due to
my students, Erni Jumilawati, Dijan Sunar Rukmi and Afif Azhar, who assisted me
in some field works. I would aiso extend my thanks to Warsa Jaya, the forest
ranger (Jagawana), for his help during my field study.
I do hope that the information in this report would serve as an additional
knowledge of the avian community of Pulau Rambut, as well as a source of
information for anyone who need it.
Ani Mardiastuti
Contents
Preface .................................................................................................................
i
I. INTRODUCTIOK
A . Background ..................................................................................................... 1
B . Objectives .......................................................................................................2
II. STUDY AREA DESCRIPTION
A . History and Location ......................................................................................
3
B. Meteorology ...................................................................................................
3
C . Topography .....................................................................................................
5
5
D. Teriestrial Flora and Fauna ...........................................................................
Ill. METHODS
A . Bird Diversity and Population Size ..................................................................8
B. Breeding Season ............................................................................................ 9
C. Nest Site Distribution ..................................................................................... 9
D. Foraging Site ................................................................................................
10
IV. ZESULTS AND DISCUSSION
A . Divsrsity of Waterbirds ................................................................................... 11
..
.............................................................
A . 1. Species Pres2nt and Compos~t~on
11
A.2. Biased in Species Identification ................................................................15
B. Population of Waterbirds ..............................................................................
17
6.1. Population Size of the Waterbird Community ....................................... 17
8.2. Patterns of Population Dynamics .........................................................
18
B.3. Bias in Population Counting .................................................................. 18
C . Assessment of the Diversity and Population Trend: Ten Years Apart
n
...........
21
- ..
v . G i e ~ d l i t yS e a s u ~
1s ........................................................................................LL
E. Nest Site Distribution .................................................................................... 24
. .
F. Idesiii-,g Assoc~ation..................................................................................
27
6 . F ~ r s g i n gArea ...............................................................................................
29
V . UANAGEMEN'T OF PULAU HAFJIGGT
A . Threats and Problem from Outside the Island
1. Deteriorating Condition of Jakarta Bay..................................................... 36
2 . Decressing Size 5f Feeding Ground........................................................ 36
3 . Disturbances from Lccai People............................................................... 36
4 . Disl~rbancefrom visitors ..........................................................................
37
5 . Possible Disiurbacce from Airport Activities ............................................. 37
B. Threats and Problem from inside the island .
1. Reduction of Mangrove Forest .................................................................. 38
2 . Poor Natural Regeneration .......................................................................
38
3 . Possible Competition with the Flying Foxes.............................................. 38
C. Management Implication
1. Predator monitoring ...................................................................................39
2 . Monitoring of Waterbird Species and Population ...................................... 40
3 . Man-made Regenerati~nfor Mangrave Forest ..........................................$0
4 . Control of Visitors ................................................................................41
5 . Improvement of Facilities and Budget ...................................................... 41
LITERATUR CITED ........................................................................................... 42
Appendix 1. Annotated Checklist of Important Birds of Pulau Rambut Wildlife
Sarictuary ..........................................................................................................
44
I. INTRODUCTION
A. Background
Pulau Rambut is a small 45 ha island ("pulau" means island) located in
Jakarta Bay area, Indonesia. This island is a very special site because it has been
used as a breeding site for waterbirds from surrounding areas. Realizing the
importance of the island for waterbird conservatiorl, since 1339 the island has
been gazetted as Nature Reserve. late; on, in 1999 the status of nature reserve
was changed into a Wildlife Sanctuary.
There are thousand of waterbirds nesting on the island, belonging to 14
species. Indonesian government protected most of waterbirds and some of them
(e.g., Milky Stork) has been listed under Birds to Watch 2 and IUCN Red List
Category. A decade ago, Mardiastuti (1992) conducted an intensive study on the
biodiversity and population of waterbirds and provided as baseline data on various
aspect. Some other research that has been conducted during the past ten years
were related to habitat mapping the island usiog Geographical Information System
(Fitriana 1999), breeding biology of the Vilky Stork (Imanuddin 2000), breeding
biology of the Little Egret (Sulistiani 1991), and distribution and diversity of waterbirds
(Mahmud 1992).
The island is located near the Jakarta Metropolitan area, which undergone
a very fast human development. The distance of the island to the nearest coast of
Java is only 3 km. Further, there is also a neighbouring island (1 km apart) inhabited
by large number of human population. Therefore, the island has been receiving a
strong human pressure.
The waterbirds use Pulau Rambut as breeding and roosting site. They have
to go out from the isiand to find food in the wetland of Java mainland. The vast
conversion of wetland into other uses (e.g., housing, rerreation areas, airport,
industrial areas) has been severely reduced the foraging areas of the waterbirds,
and might lead to decrease the population.