INTRODUCTION
The original status of Indonesian coral reef reefs
There is little doubt that originally Indonesia’s coral reefs were the richest and most diverse in the world. The region directly inherits its characteristics from the Tethys Sea fauna and is at the junction of several biogeographic regions, and tectonic plates. This gives it a variety of coral reef forms and habitats over a region of 8 million km².
However, it is also a region of high geomorphological energy derived from tectonic and volcanic activity combined with high rainfall and run-off characteristics. It is a landscape which responds rapidly and in a major way to human disturbance (
Hopley, 1999a). This is also an area in which man has been established for several hundreds of thousands of years, but it is the massive explosion of population of the last century which has led to an alarming decline in the quality of the reefs. Population in 1961 was only 97 million, by 1971 119 million, 1995 195 million, and today probably more than 200 million. Over the last 15 years data have started to give a quantitative perspective of the growing crisis for Indonesian coral reefs.
Reef surveys
Senior marine scientists in the ASEAN countries in 1982 recognised the need for coral reefs of the region to be examined (
Wilkinson et al, 1993). A research and monitoring program was formulated and methods for reef assessment recommended as part of the ASEAN-Australian Living Coastal Resources Project funded by the Australian Agency for International Development. Methodologies were published by the Australian Institute of Marine Science (
Dartnall and Jones, eds 1986) and later revised and extended to other tropical ecosystems (
English et al, eds 1994). The principal technique used was the Line Intercept Transect method (see below).
In Indonesia the task of survey was undertaken by Pusat Perelitian dan Pengembangan Oseanologi-LIPI. In the first phase (1984-89) 124 stations were surveyed. These increased to 217 by the end of the second phase (1989-94) and the data base now includes over 400 stations from 48 sites across Indonesia. For many, results from more than one period of survey are available.
In the 1990s many other surveys have been undertaken for various projects and purposes. These include university research projects and theses (e.g.
Jompa, 1996;
Limmon, 1996), and reports for national and provincial agencies such as the National Coordinating Agency for Survey and Mapping (BAKOSURTANAL) and National and Provincial Development Planning Agency (
BAPPEDA). Overseas agencies have also undertaken or participated in surveys such as during the preparatory phases of COREMAP or in conjunction with Proyek Pesisir’s target sites. The Nature Conservancy has developed a monitoring program in Komodo National Park. Since 1997 a ReefCheck program has been underway in Indonesia coordinated by the Marine Division of Yayasan and the WWF Wallacea Bioregional Program. Eight of the identified sites with 33 stations have been surveyed. Many of these programs have used similar though not always identical Line Intercept Transect methods and given the reservations discussed below, there is some compatibility which allows comparison. Results from many of these surveys have been provided to the authors and in addition some quantitative comments on the status of reefs have been included in this review.
The status of Indonesian coral reefs in the Mid 1990s
Many summaries and syntheses of the reef surveys, especially those carried out by LIPI, have been made over the last 10 years (e.g.
Wilkinson et al, 1993;
Soekarno, 1994;
Chou et al 1994a,
1994b;
Soegiarto, 1997;
Chou 1997,
1998;
Suharsono, 1998). The synthesis of the results, for various times during this period, are shown in
table 2.1.
Gross results are not comparable over time as different numbers and locations of stations are involved. However, they do show that Indonesian coral reefs are severely threatened with more than 70% being severely disturbed (in the Fair and Poor categories). At a meeting of senior ASEAN scientists in December 1993 the rate of degradation and loss of productivity of reefs of the region was subjectively assessed. The figures for the 3 regions of Indonesia are shown in
table 2.2. The area covered by this report is Central and Eastern Indonesia. These areas are considered to be in better condition than Western Indonesia. Nonetheless a four to five times increase in reef degradation is estimated over the last 50 years.
METHODS OF ASSESSING CORAL AND CORAL REEF STATUS
General
The complexity of coral reef ecosystems makes monitoring their health an extremely difficult task. They are highly variable in both space and time and the scale of this variability may not be accommodated easily in monitoring and assessment techniques (see
Done 1992a,
1992b for discussion). Unfortunately the repetitive and detailed monitoring required to overcome these difficulties and produce results which are robust and statistically testable, is generally beyond the financial and technical capability of developing countries such as Indonesia. The methods discussed below have all been used in Indonesia and though perhaps far from ideal, if their limitations are acknowledged, then they do provide at least a first estimate compromise of assessment.
Benthic cover
Estimates of benthic cover can range from very broad categories (living, dead) to surveys which detail amount and type of cover down to species level. Methods employed include manta tow, video transect, permanent quadrat and line intercept transect (see
English et al 1994 for details and advantages and disadvantages of each method).
The line intercept method has been used most widely in Indonesia. The method as used by LIPI is described by Suharsono (
1998). A measuring tape was placed across the reef and any coral colony underlying the line transect was recorded and the projected length of living coral and other organisms on the tape was measured to the nearest centimeter. Two depth ranges were sampled: the upper reef slope (3m depth) and the middle reef slope (10m depth). At each depth a set of 3 replicates 50m long positioned parallel to the shoreline were surveyed using SCUBA. Sessile benthos underlying the line transect were classified into 27 categories at the life form level (
English et al 1994). Field data were entered into a dBase program for storage, checking and analysis.
Limitations of the method as applied to Indonesian reefs in particular have been given by Tomascik et al (
1997). One of the main criticisms is that reefs with highest % cover may occur in regions with fewest natural disturbances, and reefs may be dominated by monospecific communities and therefore not be optional biodiversity sites for conservation. However, as shown in the summary
table 2.3 number of coral species is normally recorded at each site. Moreover, the total data set is far more detailed than has yet been published in any summary paper.
The reviews of the health of Eastern Indonesian reefs as given in sections 2.3 and 2.4 are essentially based on the methods described here and provide the best data set available for the region.
Diversity
Although coral species numbers are frequently recorded in Indonesia, in a raw form they can give only a superficial indication of reef health. Species recognition is difficult for persons not trained in taxonomy. However, the greatest problem lies in number of species being dependent on a wide range of factors including ambient environmental conditions, number of niches present and time since, and frequency of, natural disturbances. A slightly more sophisticated approach has been used by Edinger et al (
1998,
in press a). Using data from line intercept transects they derived species: area curves. However, this was also combined with a Mortality Index derived from:
Live coral cover / (Live coral cover + dead coral cover)
Although applied to only 14 reefs throughout Indonesia, the results to which robust statistical techniques were applied did indicate the effects of degradation on reefs. The resulting rating of degradation types was (from good to poor):
- Eastern Indonesian reefs used as control
- Java Sea reefs
- Mechanically damaged reefs at 10m depth
- Eastern Indonesian polluted reefs
- Mechanically damaged reefs at 3m depth
- Java Sea polluted reefs
The eastern Indonesian reefs used in the study were from Ambon and the Spermonde Archipelago including those shown in
table 4.2. Mortality indeces ranged from less than 0.2 at damaged, especially land based polluted sites to over 0.5 at less affected sites.
Edinger et al (
1998) also used an earlier survey by Moll (
1983) to show a change of diversity over time in the Spermonde Archipelago of South Sulawesi. They show a 25% reduction in number of genera recorded at Samalona and Barang Lompo reefs between 1980 and 1995.
Using the same data sets as Edinger et al (
1998), Edinger and Risk (
1999) used ternary diagrams to assess “conservation value” (proxy health). The ternary diagrams were constructed by summing the total cover of three adaptive strategy groups:
- ruderals (disturbance adapted) – Acropora sp. corals due to their rapid growth rate and mechanical fragility.
- competitors – branching non-Acropora corals and foliose corals which grow and recruit more slowly than Acropora.
- stress tolerators – massive and sub-massive corals more tolerant of high sedimentation and/ or eutrophication.
Edinger and Risk (
1999) claim that the resulting aggregate conservation classes predict conservation value more reliably than the reef condition indeces currently being applied, i.e. live coral cover or coral mortality. They also believe that much of the data collected for Indonesian reefs over the last 15 years is adaptive to this methodology.
Growth rates and calcification
Growth rates, especially of massive corals, have been advocated as a test of coral health. However, simple skeletal extension rates may be misleading for, as shown by Rasmussen (
1988) in experimental tanks, and by van Woesik (
1992) in the field, corals under eutrophication stress may continue to grow at non-stressed rates, but lay down a less dense skeleton.
This has been confirmed in Indonesian corals by Edinger et al (
in press b). They conclude that tissue stable isotopes and bio-eroder organism counts may be reliable indicators of eutrophication. They also suggest that the acid insoluble content in coral skeletons reflected land-based pollution stress on reefs more reliably than simple coral extension rates.
A further technique which could be used to measure reef health, is “community metabolism” (see
Kinsey, 1985 for review and discussion). Measurements of gross photosynthesis fixation, gross respiratory consumption and inorganic gain (calcification) can all be made from water chemistry measurements and produce results within predictable ranges for different “healthy” reef zones, with departures from these values on stressed reefs. Unfortunately the method requires sophisticated equipment and is not suitable for most developing countries.
Coral recruitment rates
Coral recruitment has been measured either through counts of young colonies appearing on reefs between successive sampling periods, or by using artificial substrata (tiles) which are removed from the reef for laboratory examination (see
English et al 1994, for discussion and methods).
The method is being applied in Indonesia. In early 1998 Fox (in press.) commenced a recruitment experiment at 5 sites in Komodo National Park. Results may indicate the effects of various types of stress and also aid in rehabilitation.
Other indicators
Numerous other indicators of reef health are available including the use of indicator species but few have been used on Indonesian reefs, and those that have, have had relatively geographically restricted application. Reef fish diversity biodiversity indeces have been used by Allen (
1998,
in press) and discussed in Section 3. Stomatopod crustacean populations (
Erdmann and Caldwell 1997) and isotopic composition of nitrogen in stomatopod tissue (
Risk and Erdmann, in press) have been studied as bioindicators of pollution stress in the Spermonde Archipelago (see Section 4.3.3 and
table 4.2). A clear stress impact aureole outwards from Makassar city is shown by their studies.
CORAL CONDITION AS SHOWN BY THE LIPI DATA SET
The data set
The most cohesive data set for Indonesia is that of Pusat Penelitian dan Pengembangana Oseanologi-LIPI (P3O-LIPI). The information used here is updated and includes some observations before and after the 1998 bleaching event, though this affected western rather than eastern Indonesia (see Section 5.3). Results are shown in
table 2.3 which provides the data collected pre 1998, the 1998 set (not all sites were updated) and the latest 1999 set. Number of stations and number of genera recorded at each site are shown, together with dominant species and notes on the environment. Transects are aggregated for each location and classified as having excellent, good, fair or poor live coral cover (for definition see
table 2.3). Only stations which occur in Eastern Indonesia, as defined by this review are listed. These include all those of eastern and central Indonesia as defined by LIPI plus Bali and the Kangean Islands which they place in western Indonesia. Station numbers are those used in the 1999 LIPI data set, (
Fig 2.1).
The data confirm all the concerns for Indonesian reefs expressed over the last 20 years. In Eastern Indonesia only one surveyed location may be regarded as in excellent condition and that is the Lucipora Islands located in the middle of the Banda Sea in Maluku. Of the 28 stations within the review area a further 12 are regarded as being in good condition, 12 in fair condition and 3 in poor condition. Of those in poor condition, 2 are in the heavily used areas of Bali and Lombok but a third is the Morotai Islands in the far north of Maluku indicating that remoteness is not a protection against overuse and destructive fishing practices, (
Fig 2.2).
Stations located in the Flores Sea (including the marine protected areas of Take Bone Rate and Tukang Besi (Wakatobi National Park) are in only fair condition. Sites in Nusa Tenggara east of Lombok (Komodo, Rinca, Sumbawa) appear to be in reasonable condition, although the Wetar Islands in the far east are only fair, a condition attributed to gold mining. Central Maluku reefs also appear to be in reasonable condition apart from the Kai Islands. The protected areas of Cenderawasih Bay and Biak in West Papua are classified good, but concerns should be expressed for the Padaido Islands where 4 of the 13 stations are classified poor. In East Kalimantan the reasonable condition of Palau Sangalaki is not matched by nearby Derawan.
Of the locations within Eastern Indonesia, comparison between the 1999 survey and those of earlier years (
Fig 2.3) indicated no change at 21, 5 with deteriorating condition and 2 at which conditions had improved during the 1990s. These 2 stations are the strategically important Tukang Besi Islands and Take Bone Rate. However, in both cases there has been a reduction in the number of stations (from 24 to 5 in Take Bone Rate and from 10 to 5 in Tukang Besi) and the result may be an artefact of the choice of remaining stations.
The locations showing a deterioration in cover are:
- Bali, where all stations are now classified as poor
- Lombok, where pre 1998 2 stations were classified as excellent and 2 as good, now 22 out of 24 are poor, the remaining 2 fair
- Kangean Islands, where the decline may be due to a reduction in station numbers from 9 to 7
- The Togian Islands, where a small apparent decline is probably the result of increasing station numbers from 5 to 8 (50% are classified as good)
- Padaido, where in spite of the loss of one station there is a clear decline over the 1990s.
Given the degree of synthesis in the results, it is probable that analysis of individual transects in many areas will show a more widespread decline thus confirming anecdotal evidence and the survey results from other organisations given in the next section.
DATA SETS FROM OTHER SOURCES
Origin and quality of the data
Many regional reports, papers, data sets and theses have been provided to the authors of this review. They are of varying dates and quality, using a variety of methods (though mainly Line Intercept Transect) and many may in fact re-use of some of the original LIPI surveys. Because of difficulties of compatibility these data are discussed by Province, rather than holistically for the area of Eastern Indonesia.
East Kalimantan (Table 2.4)
Only limited data are available to supplement the LIPI sites at Sangalaki and Derawan. They are the result of manta tow surveys of 4 sites, all in northern East Kalimantan. Dead coral observations outweigh live coral at all sites and is particularly prominent at Derawan (confirming the LIPI results) and Kakaban.
North Sulawesi(Table 2.5)
Data came from COREMAP reports, Proyek Pesisir sites and observation provided by Chou Loke Ming. From north to south the sites are:
- Northern Islands (Tamako, Talise and Bangka) Conditions are variable with about 50% coral cover at Tamako (Sangihe Talaud Regency) (Lalamentik et al, 1996), typical of the other sites for which full transect data are available. In P. Talise and P. Kinabokuten coral cover ranges from 43 to 82% and although little or no bomb or cyanide damage is present, the area is overfished.
- Manado – Bunaken Park area Considering most of these sites are in the Bunaken National Park area, their condition is only fair. Best cover is found around the southern side of Bunaken (57 – 72%) cover.
- North Coast These sites are also highly variable with coral cover typically 20-50% and dead coral 31-75%. Bleaching has been reported from many of the sites. The effects of blast fishing are seen throughout the area.
- South Coast The south coast has had some good and even excellent condition sites but there is a high anthropogenic stress. Many of the sites for which data is given lie around the gold mining area of Ratatotok and adjacent waters but some of the best sites were reported from here in the mid 1990s. Significant bomb damage and Crown of Thorns outbreaks are reported around Bentenan Island.
Central Sulawesi (Togian Islands, Peninsular, Banggai Islands) (Table 2.6)
Two surveys of the Togian Islands are available. That of 1998 by Conservation International shows a similar average live coral cover to 1993 but with a significantly large figure for dead coral. C.I. believe the islands have a better coral reef condition than elsewhere in Sulawesi.
In general the coral reefs of the mainland (Peninsular) appear to be in better condition, with cover greater than 80% at several sites, though there are also sites with less than 25%. Results are similar for the Banggai Islands.
Sequential surveys by YABSHI are available for the northern Malenge Islands taken in 1995 (Hutabarat) and 1997 (Anwar):
An approximately 22% degradation is noted in the 2 years and is attributed to increased use of destructive fishing practices as the economic crisis deepened.
South-west Sulawesi (Wakatobi) (Table 2.6)
The result from P. Tomeo from Chou L.M.’s 1999 survey suggest a higher cover than the LIPI data (station 28, Tukang Besi).
South Sulawesi
Apart from qualitative comments on the Sembilan Islands in Bone Bay, survey data are limited to the Spermonde Archipelago and Taka Bone Rate, already part of the LIPI network.
- Spermonde Archipelago Good data are available, including the M.Sc thesis of Jompa (1996). This indicates a decline in coral cover from the outer reefs (66.6%) to the reefs closer to Makassar City (14%) as shown table 4.2. COREMAP reports (1996) show similar cover, though noting that in the mid 1990s some areas of 100% Acropora cover could be found on outer reefs. However, bomb craters were observed at many locations but with many young corals indicating active recruitment. Later unpublished surveys by COREMAP have suggested a decline in areas resurveyed in early 1997 and late 1998, with some bleaching being observed.
For example, Barang Lompo reef has seen a decline in coral cover from 46.5% to 42.0% in this period.
- Taka Bone Rate COREMAP (1996) noted that coral cover was normally between 10% and 60%. M ore recent surveys by ReefCheck (1998) and Chou (pers. comm) have shown that some areas still have higher cover (P. Tinjana, P. Tinabo), in contrast to the most recent COREMAP (1999) observations of only 22% cover at P. Latondu.
- Sembilan Islands Some of this group of 9 islands were regarded by COREMAP (1996) as being relatively undisturbed though evidence of both blast fishing and Crown of Thorns starfish was observed. Especially degraded were the reefs of P. Kambuno, P. Burung Loe, and P. Batang Lampe. Least damaged were the reefs of P. Larea-rea.
Bali
Reports in the early 1990s (e.g.
Biro BKLH Setwilda Tingkat l Bali 1992) suggested that the reefs of Bali were in reasonably good condition. However, more recent surveys such as those of ReefCheck (1999) show differently with some very low live coral cover and high dead coral figures (
Table 2.7).
Importantly some comparative surveys are available. Van Woesik (
1997b) undertook detailed surveys at Sanur and Nusa Dua, southeast Bali in September 1992 and September 1997. The reef changed from being dominated by coral to being dominated by macroalgae, sponges and filter feeders, a clear sign of eutrophication (
Table 2.8).
In 1992 the upper reef slopes supported good coral cover (73%) and high coral diversity with dominant Acropora sp. and Seriatopora sp. averaging 17-24cm diameter. The same reefs in 1997 supported approximately 15% cover, dominated by encrusting Montipora sp., Porites sp., faviids, macroalgae and sponges. The average colony size was only 2-3cm. Over 70% of the reefs at both sites were covered by algae, with massive and encrusting sponges and zoanthids now prominent. The reefs by 1997 was in a very poor condition.
Even more recent evidence of decline is available for Amed, (
Table 2.9). Surveys since 1997 indicate that coral cover has declined 50-80% in 1998-9 with a significant increase in algal cover. Highest mortality was at 10m depth and is associated with massive bleaching. Surface water temperatures increased from 25.39°C in September to 29.02°C in December 1997, staying high until t he second half of 1998, (
Zamani et al, 2000 in press).
West Nusa Tenggara
Little information additional to the LIPI data for Lombok and Sumbawa is available. COREMAP (
1996) has described the condition of the reefs in Sumbawa, western Lombok and the Gili Islands in the mid 1990s. Coral cover was very variable ranging from <10% to >80%. On the islands the deeper slopes appeared to have suffered greatest damage from bombing with shallow reefs in better condition, but results varied.
For example on Gili Trawangan the eastern slopes had only 20-30% cover whilst western slopes had 60-80% and on Gili Meno a cover of <30% on the east coast contrasted with 60-80% on the north. Lombok mainland reefs generally had <30% on the reef flats and a b out 50% on the slopes.
In Sumbawa many reefs were of high quality when surveyed in 1993. Cover of living coral ranged from a minimum of 7% at P. Brangkoa to a maximum of >75% at P. Satonda. Impacts noted were the effects of blast fishing at P. Satonda and Labuan Haji (up to 90% damage) and possible freshwater influx or temperature excursions at Teluk Saleh.
East Nusa Tenggara
Results are available for 3 sites:
- P. Rinca
The P. Rinca Expedition of 1994 (Moosa, 1994) provided some indicators of coral cover. They ranged from 10% at P. Siaba to 94% at P. Sabayor Besar a t 3m, and 0.6% to 96.1% at P. Sulaeman.
- P. Riung
ReefCheck have 3 sites (Table 2.7) in the P. Riung area with that at P. Tembaga showing 72.5% live coral cover, though a figure of 8.8% for dead coral suggests some degree of damage.
- Komodo National Park
The Nature Conservancy has 185 sampling sites around Komodo. Initial surveys in 1995 showed up to 50% of reefs damaged. However, since then there has been a major decline in the use of destructive fishing practices due to a combination of enforcement and increased community awareness. The most recent results (Djohani et al, 1999; Pet 1999; Fox et al in press) show an increase overall in hard coral cover from 16% to 20%, and an increase in soft coral cover (mainly Xenia sp.) from 22% to 24%. The coral mortality index has declined from 63% to 52%. Although areas adjacent to the Park show improvement, it is the reefs closest to Park headquarters which show the greatest benefits, live coral cover increasing by 4 to 10% and dead coral decreasing by 10 to 15%. The most significant rehabilitation occurs at Labuan Bajo, the Park Buffer zone, KNP Rinca and KNP Komodo.
Maluku
Detailed surveys have been carried out at a number of sites around Ambon by Limmon (
1996) (see also
Edinger et al 1998,
1999). Reefs at the reference site were in reasonable condition (64% hard coral cover) but at the nearby locations, with a variety of stresses, coral cover was only half of this figure or less.
COREMAP (
1996) has made some observations on the project sites at Kotania Bay and the Lease Islands. Surveys for the early 1990s at Kotania showed coral cover of 25-83%, with soft corals making up 2-31% of the substrate. More recent observations show soft corals now dominating at 10 out of 15 sites, with over 50% cover at some. Soft corals are also dominant at some sites (e.g. Saparua) in the Lease Islands. Significantly, 65% of manta tows showed evidence of bomb damage and in one area where 13 months earlier there had been live coral cover of 51-76%, later surveys showed only rubble.
West Papua
On Padaido COREMAP (
1996) report widespread and substantial coral damage, in part due to the 1996 earthquake, but more from widespread use of dynamite. Coral covers of 15-72% are reported but in 1996 only 8 out of 80 manta tows recorded >30% cover.
On Biak-Supriori coral cover measured in 1995 (
Wouthuyzen ed., 1995) was 20 to 87% at 3m depth, but only 10-49% at 10m where algal cover increased dramatically.
The reefs of West Papua have experienced much bomb and cyanide damage but destructive fishing practices are considered to have reduced in the last 5 years as tourism has increased. However, very little information is available for the majority of reefs of the province.
Assessment
The LIPI data set and information from other sources show similar patterns and confirm the poor state of many reefs in Eastern Indonesia. The causes of degradation are discussed in Sections 3 and 4 but it appears that not even the most r emote reef h as been safe from exploitation, often by people from outside the immediate region. Destructive fishing practices and over exploitation have had serious effects even in marine protected areas. That relatively simple management practices can produce a halt in the degradation process, however, is illustrated by the Komodo National Park, where implementation of management policy, aided by The Nature Conservancy, is having very beneficial effects.
This review cannot claim to incorporate every reef survey carried out in recent times. However, we believe that it is comprehensive. It is disappointing, therefore to find that monitoring efforts have been concentrated in a relatively few sites. It appears that in some small areas, several independent surveys have been carried out relatively close together. Conversely there are enormous areas for which there appears to be little if any information. These include the Great Sunda Barrier Reef, the west coast of Central Sulawesi, many of the islands of Nusa Tenggara, some of the large islands of Maluku such as Halmahera, Buru, the Tanimbar Islands and the Aru Islands, and most of West Papua apart from Cenderawasih Bay.
The general condition of coral reefs in Indonesia does appear to improve from west to east (
Table 2.10), but the methodologies used and the patchiness of the data compared to the density of sampling, cannot provide the full picture. More detailed survey and monitoring is needed to indicate where conservation measures will have most effect.