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Incidence of Fish Hook Ingestion by Komodo dragons June 30, 2008

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Incidence of Fish Hook Ingestion by Komodo dragons

Tim Jessop1, Jeri Imansyah2, Deni Purwandana2, Achmad Arifiandy2 and Devi S. Opat3

1Department of Wildlife Conservation and Research, Zoos Victoria, PO Box 74 Parkville VIC 3052, Australia

2 Komodo Dragon Species Survival Program Indonesia, Denpasar, Bali, Indonesia.

3 Taman National Komodo, Labuan Bajo, Flores, NTT, Indonesia.

Correspondence to Tim Jessop

(e-mail: tjessop@ zoo.org.au).

The Komodo dragon (Varanus Komodoensis), a large robust monitor lizard, persists on the 5 islands in Eastern Indonesia (Ciofi and deBoer 2004). The waters surrounding these islands are intensively utilized for marine resources and in particular line and net fishing are prolific. For other reptiles, particularly freshwater and marine turtles, incidental injury and mortality through ingestion of fishing hooks during routine foraging activities are not uncommon (Polovina et al. 2000). However, similar incidents of reptile by-catch in terrestrial species is poorly documented even though, many large lizards such as monitors, are semi-aquatic or cohabit and forage within coastal areas in which intense fishing activities persist. Here we report two incidents of ingestion of fishing gear by Komodo dragon during routine monitoring of island populations between 2002- 2006.

Annual mark recapture studies were conducted at 10 sites across 4 islands within Komodo National Park during both 2002 and 2005 and resulted in 827 dragons captures(> post-hatchling size). From this sample, 2 cases of fishhook ingestion were reported. The first case, comprised a small monitor (Animal ID: 00063A9978, 69.35 cm SVL, 7 kg) captured at Loh Buaya (8:39:21.7 S, 119:43:06.2 N) on Rinca Island and appeared to occurred recently as the line protruding from its mouth was still relatively long and the nylon in good condition. Based on the line weight it is suspected that the hook ingested by this lizard was relatively small. This lizard was recaptured in 2005, without any evidence of the protruding fishing line (however if the hook was remaining is unknown) and it had grown 8.75 cm in SVL and increased its mass by 1.45 kg. The second lizard, an adult male (Animal ID: 000643A7EC, 127.75 cm SVL, 41.8 kg) was captured on the 19th June 2004 also from Rinca Island at Loh Tongker (8:45:31.1 S, 119:42:57.3 E) a small coastal valley on the south east coast. In this incident the hook ingested was likely to have been considerably larger and typical of those used for capturing large pelagic species on long line. This hook was shackled with 2 strands of heavy trace wire (Fig 1). In this instance it is believed the hook was ingested several weeks to months earlier as indicated by the lesion induced by abrasion from the trace wire. In 2005, this adult male was recaptured, there was no evidence of the protruding trace, however it was not known if the hook still resided within the animal. The weight of this male had decreased by 8.8 kg from 2004 and 20 kg from its first capture in 2003 despite growing relatively little in length (4 cm in SVL).

Consumptions of fishing hooks by Komodo dragons, albeit rare, is a likely consequence of these lizard’s prodigious scavenging capacity coinciding with discarded fishing gear that finds it way into the intertidal areas exposed on the low tide. As yet we do not know what effects hook ingestion might incur for the specific individuals dragons, however, given that mortality occurs readily in other reptiles, it is possible that at least in the case of the second animal there may be negative consequences.


Ciofi, C. & de Boer, M.E. 2004. Distribution and conservation of the Komodo Monitor (Varanus komodoensis). Herpetological Journal 14: 99-107.

Polovina, J.J., Kobayashi, D.R., Ellis, D.M., Seki, M.P., & Balazs, G.H., 2000. Turtles on the edge: Movement of loggerhead turtles (Caretta caretta) along oceanic fronts in the central North Pacific, 1997-1998. Fisheries Oceanography 9(1):71-82.


Apparently immaculate Komodos hatched February 12, 2008

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Apparently immaculate Komodos hatched

Yahoo news, Feb 7 2008

WICHITA, Kan. – Two Komodo dragons have hatched at the Sedgwick County Zoo, apparently without the fertilization of a male. The dragons, both males, are believed to be the first in North America known to have hatched by parthenogenesis, which occurs naturally in some species, including invertebrates and lower plants. It happens more rarely in some vertebrates.

Two other known cases in which Komodo dragons hatched by parthenogenesis were at the London and Chester zoos in England in 2006.

The zoo in Wichita is having DNA testing done to document the mother’s and the babies’ genetic structure because of the remote chance that a male’s sperm was stored on the female’s body.

Komodo dragons are one of the few species capable of storing sperm, said Don Boyer, curator of reptiles and amphibians at the San Diego Zoo and species survival plan coordinator for Komodo dragons.

The Sedgwick County Zoo has had this female and one other since 1993, when they were less than a year old. They have been laying eggs since 2000.

“We never had a male dragon at the zoo. There were no tramps that came wandering through,” said Nate Nelson, the zoo’s curator of amphibians, reptiles and fishes.

One of the Kansas zoo‘s females, Gaia, laid at least 17 eggs on the nights of May 19 and 20, 2007. The females can lay as many as 30 eggs at a time.

Because the English zoos had documented parthenogenesis, thApparently immaculate Komodos hatchede Sedgwick County Zoo checked to see whether the eggs were fertile. Only two of the 17 eggs were hatched — one on Jan. 31 and the other Feb. 1 — because the zoo doesn’t have room for more dragons, Nelson said.

One is 16 inches long; the other is 17 inches. Komodo dragons can living 20 to 40 years. Males can reach 10 feet long and weigh as much as 200 pounds; females grow to between 5 and 7 feet and weigh as much as 125 pounds.

Komodo dragons are endangered, with between 3,000 and 5,000 in the wild. Eighty live in 30 zoos in North America. Only six zoos in the nation breed the dragons.


source : http://news.yahoo.com/s/ap/20080207/ap_on_fe_st/odd_komodo_dragons

On the Net:

Sedgwick County Zoo: http://www.scz.org/

Latest news from the Wae Wuul Protection Plan for Komodo Dragons January 17, 2008

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Latest news from the Wae Wuul Protection Plan for Komodo Dragons

source from Chester Zoo’s Action for the Wild


Posted: 02/07/2007
The Wae Wuul Protection Plan is based on the island of Flores in Southeast Indonesia. In 2001, population densities of Komodo dragons on this island were estimated at 1 individual per 20 hectares. This is a marked decrease from surveys in 1991, probably caused by human-related pressure on natural habitats in the Wae Wuul Reserve, through poaching, cultivation of land and collection of firewood.

The 2006 Komodo dragon conservation programme commenced in the dry season in July 2006. Administration issues with the local authorities were dealt with in July, with staff from Komodo National Park and the Nature Resources Conservation Office working on a long term agreement regarding joint management of the Wae Wuul Reserve. A Non-Governmental Organisation, the Komodo Survival Programme, was formed early in 2007, requesting that the European Association of Zoos and Aquaria act as a supervisor of this Komodo dragon conservation project.

Field activities followed in August and September 2006 devoted to community awareness activities and patrolling of the Wae Wuul Reserve. Community awareness activities are vital for regular interaction with the members of the 8 villages living outside the reserve to show continuous commitment to conservation, to help minimise the levels of encroachment in Komodo dragon habitat and to explain the long term effects of intensive poaching on wildlife in the reserve. Lectures in the community awareness programme covered descriptions of the current status of the reserve and its wildlife, a review of policies against cultivation and exploitation of the reserve and an outline of the activities to promote conservation and monitoring. Soon after the community awareness programme, patrolling activities commenced, conducted solely by the villagers and representatives of the Indonesian Department of Forestry. These patrols took place on alternate days in September, along 5 patrolling paths. Throughout such patrols, the villagers recorded feral dogs, signs of hardwood cuttings, a fire along the reserve boundary, and goat and water buffalo herds within the reserve boundary. These results indicate a reduced human pressure compared to 2005, possibly indicating the effectiveness of patrolling activities in the last 2 years. The feral dogs still, however, pose a threat as they hunt deer, a prey species of the Komodo dragon.

It is hoped that once the Wae Wuul Protection Plan becomes established as a regular, annual initiative then such activities within the park boundaries will stop completely and Komodo dragon numbers will increase.


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In regard of Collaboration preparation between Komodo Survival Program and the Balai Besar Konservasi Sumber Daya Alam NTT.

A field trip to visit Wae Wuul Nature Reserve was conducted on December 16th, 2007, as part of our partnership with KSDA NTT to implement capacity building and conservation project of Komodo dragon and it’s environment on Flores. From the field trip, we identified several key findings that are important to implement.

  1. Renovation of Ranger Station.

Current ranger station is urgently to renovate as it is important to provide a more suitable condition for the rangers, volunteers, researchers, and stakeholders to utilize the station as basecamp of conservation works in WWNR.

  1. Reconstruction of zonation.

Most of the border marks (Pal, In Bahasa Indonesia) are missing. Thus the border in which separating nature reserve area and private land is unclear. This situation is could potentially causing a conflict between WWNR authority and local communities around the reserve area.

  1. Developing biodiversity and key species data base.

To date, no scientific information on biodiversity potential of WWNR is available as basic for the reserve authority to design and implement appropriate conservation and management strategies. Thus biodiversity assessment and documentation as well as developing data base are necessary to undertake.

  1. Developing specific study, monitoring and conservation strategies of Komodo dragon including the habitat.

Considering the habitat of Wae Wuul, a specific monitoring and conservation strategies of Komodo dragon and other key species, including the habitat should be considered to design. This requires a comprehensive assessment of potential and threats. Broad scale involvement of various stakeholders is necessary.

  1. Capacity building.

To enhance capacity and human resource skill of KSDA NTT staff in managing Komodo dragon and other key biodiversity in WWNR, capacity building activities, i.e trainings should be implemented. Specific trainings should be carried out base on the needs and priority that important to the management in WWNR.


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We are now developing a Komodo dragon and human interaction management protocol that provided for the Komodo National Park authority to manage human-komodo interaction within tourism-concession areas. This draft is need to be further developed, therefore any suggestion are most welcome… to give comment or suggestion, please email us at komodosspi@centrin.net.id or mjimansyah@yahoo.co.id, or phone +62 361 7420434, or fax +62 361 710352.





Komodo National Park was established in 1980 to ensure the long-terms survival of Komodo dragon (Varanus komodoensis), the largest living lizard in the world and the quality of its habitat (Erdman, 2004). Komodo dragon is protected species under Indonesian government regulation No. 8 1999 (Indonesia.1999). It is also listed in appendix I CITES, classified as vulnerable by IUCN (World Conservation Monitoring Center, 1996). Recently, the endangered status of Komodo dragons has been proposed to be updated following the reduction on populations, distribution and the evidence of population fragmentations (Ciofi & de Boer 2004).

Human activities within Komodo National Park has been existing before Komodo National Park established; even it is might be limited to human and wildlife interaction on local community such as nature resource harvesting (including terrestrial fruits and marine life). Apart from local community, human activities in tourism sector increased after Komodo National Park established, although UNESCO reported the statistical number of visitor showed steady decrease since 1997 to 2001 (from 29,842 to 12,612 respectively). With approximately 3000 people living in the park (located in Komodo Island, Rinca Island and Papagaran Island) (Erdman 2004) and a numbers of tourist visit Komodo National Park, it is important for management authority to manage human activities wisely along with wildlife (especially Komodo dragon and its habitat) in regard to create sustainable profitable human activities within the park including tourisms.

Due to the occurrence of interaction between human and Komodo dragon, therefore, the management authority will require a guideline for managing sort of interaction. A guideline on how human and wildlife could interact for sustainability of live hood with survival of wildlife is necessary to be developed. The guideline is including certain procedures that can be implemented by park authority within Komodo National Park.

Identification of Issues

1. How to reduce human impact on Komodo dragon and other wildlife

Wild animals are sensitive to variety of human activities, such as Bald Eagles are sensitive to visibility and noise levels (U.S. Fish and Wildlife Service 2007). The impact of human activities on Komodo dragon has documented by Lilley in Monk et al (2000), especially feeding attraction for tourist that change the natural behavior of Komodo dragons for hunting their preys. Another evidence were reported by Purwandana (2007) where nesting female avoiding human that approach to their nest.

2. How to increasing presence of Komodo dragons and others wildlife as tourism attraction.

In contrary, within tourism area, there are evidences of Komodo dragons difficult to find by tourist especially during mating season. There are several actions needed to solve the problems on managing the Komodo dragons along the tourism path.

3. How to reduce Komodo dragon’s impact on humans

The park authority should prevent the probability of wild life attack on human (villagers and tourists). The occurrences of Komodo dragon attack people (villager and tourist) should be consider as references on managing this animals when interact with people.

Management actions

Several management actions are required to be implemented by park authority in order to address the issues;

1. Alternative jungle tracking / tourist paths.

à Alternative tourist path are necessary to established as substitute to the existing paths that crossing or near Komodo dragon’s nests is essential to construct and utilize during nesting season to reduce disturbance to females.

2. Limit number of visitors in a group

To reduce human impact on Komodo dragons:

à Limit the maximum number of people in a tracking group (We recommend not more than 10 people). The aim of this action is to minimize impact of visitors disturbing Komodo dragons and other wildlife.

à The gap between groups should be hold for 10 (ten) minutes each. This should be followed by sufficient number of guides. Maintaining gaps between groups will reduce the impact of human on wildlife, by minimizing contact between wildlife (especially Komodo dragons) and human. Funds should be provided for radio tranceivers to be allocated to rangers during guiding tours, in order for them to communicate with the sentry post and coordinate walking paces with preceding or following tourist groups.

à For specific flora or fauna observation interest, such as birdwatching, activities, it is more comfortable a group consist of maximum 3 people.

3. Establish observation platform or tower.

à This kind of action should be taken in order to reducing impact of human activities to active Komodo dragons nest or Megapode bird nest. The observation platform/tower could be permanently far from nest location (Jessop et al. 2004 has identified almost all nest location in Komodo Island). Another option is the alternative paths during nesting activities (Komodo dragons and Megapode bird).

4. Waste Management

Waste management should eliminate the attractiveness of Komodo dragon and other animals disturbing rubbish, and change the animal’s behavior to stay around the camp.

à Plastics material should not left in the islands. Plastics bags (from food) could eat by Komodo dragons and damage their digestive system.

à Rubbish from food (chicken/fish bones) should left from bungalows, ranger’s kitchens, and restaurant because Komodo dragons may still hang around the camp and change their natural behavior such as hunting. However, this is not immediately change the behavior of Komodo dragons around the camp, as the present situation has been going on for long time ago (more than 10 years).

5. Terrestrial Monitoring and Surveillance.

à Terrestrial monitoring and surveillance should focus on how to reduce number of illegal poaching (especially for deer) and illegal logging. Partially in Loh Liang, Illegal deer poaching might not occurred. However, evidence of illegal logging (including harvesting Tamarind and Srikaya fruit) in Loh Loh liang are frequently happened by villagers. Consider Loh Liang as tourism area, totally eliminate villagers activities are important. As the result, compensation area should be provided (Loh Kubu and Loh Bube)

6. Hanging bait

à Hanging bait might be performed in order to increase number of Komodo dragons sighting. However, this have to be wisely execute in order to eliminate behavior changes, therefore the Komodo dragon still hunt their preys. This can be done such as in random place and random time (once every month) along tourist paths

7. Establish and maintain artificial waterponds

à To increase wildlife sighting, rearrange artificial waterponds might become a consideration. This was demonstrated by Smit et al. (2007) on ungulates distributions in Africa are affected by location of artificial waterhole. Artificial waterhole may include next to the nest to increase probability of nesting females get enough food for body recovery.

8. Educations

à Certain education should conducted by park to villagers, people from Flores and Sumbawa mainland, including tourist. The material of education should encourage people to be wisely interact with wildlife, safety information when visit park, educate people to responsible of their own rubbish.


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In archipelagoes such as Indonesia, a nation with extraordinary high levels of biodiversity and endimicity, and where human perturbation is not uncommon, even within protected areas, overcoming the intrinsic biogeographic variation of managing such biodiversity is likely to be another challenge for conservation efforts. Komodo National Park (KNP) is a world heritage site, this area has a high biodiversity of tropical marine and the only potential habitat of giant endemic reptile Komodo dragon (Varanus komodoensis). Like most of National Parks in Indonesia, wildlife management in KNP restrain by less of reliable monitoring data base, because of limited source of fund, logistic, and local staff capability (Jessop et al., 2004). This guideline provides methods which technically can be adopted and used by KNP management to collect high accuracy and reliable database.


The major outcomes of this guideline are to increase knowledge of differences among island within

KNP with respect to prey availability and its influence on the demographic features of Komodo dragon populations. Second, collection of the appropriate life-history information that can be used to build specific population models that could assist in the management and conservation of key terrestrial species within KNP. Third, increasing the capacity of staff from KNP to effectively monitor wildlife populations within the park.

Specific Aims to research:

1. Life history and demographic differences in Komodo dragon populations across 4 islands within KNP.

Mark-Recapture studies should be used to assess demographic variation among island populations with respect to the following demographic parameters:

a) Population abundance of Komodo dragons at 10 study sites across four islands.

b) Age specific growth rates of Komodo dragons at 10 study sites.

c) Spatial ecology of Komodo dragons at 10 study sites

d) Assessing annual female reproductive rates across specific island sites

e) Hatchling production to assess variation in recruitment

f) Sex ratio.

Also recommend for further studies

f) Age specific survival rates of Komodo dragons at 10 study sites.

g) Parasitological (health and desease) of Komodo dragon

2. Prey density and diversity among four islands within Komodo National Park.

These monitoring activities will quantify temporal and spatial difference of large ungulate prey within Komodo National Park. Key criteria gathered from this monitoring include the following parameters. Knowledge of these parameters is essential for determining interactions between Komodo dragon and their prey.

a) Spatial and insular differences in density of Timor deer in KNP.

b) Spatial and insular differences in density of wild pigs in KNP.

c) Spatial and insular differences in density of water buffalo in KNP.

d) Spatial and insular differences in density of rats in KNP.

e) Spatial and insular differences in density of tokay geckos in KNP.

3. Assessment of habitat and other key and endangered species

a) Assessment of food resource (grass) availability

b) Active nest of Megapode birds

c) Active nest and direct population counting by vantage count for Cockatoo

d) Monitoring diversity of birds

e) Assessment the presence of exotic/invasive species


Field Methods

1. Life history and demographic differences in Komodo dragon populations across 4 islands within KNP.

Mark Recapture is a very effective method that most scientists implement to collect information on population ecology, age specific growth rates and spatial ecology (inter valley or inter islands migration) of Komodo dragon. Radio telemetry method is applied to assess more detail spatial ecology, i.e. movement pattern, home range, and behavior. Nest survey method that implemented transect grids method is very useful to assess annual female reproductive rates. Nest fencing method also useful to assess variation in recruitment by counting hatchling production from active nests.

Mark recapture

Komodo dragons are captured by baited trap, noose or by hand. These methods are extremely effective for capturing all size classes of monitor above yearlings, which are largely arboreal. This trapping technique requires a 300 cm x 50 cm x 50 cm long box traps baited with goat meat (≈ 0.5 kg). Distance between traps is recommended between 200 m and 700 m from each other, depending on topographical and vegetation. Traps are positioned in shaded areas in order to avoid overheating of trapped individuals and are checked twice daily.

Following capture, Komodo dragons are restrained with rope and their mouths taped shut. Several morphological characters, including head length, and snout to vent length (SVL) are measured using calipers and a fiberglass tape. Body mass is obtained using digital scales. Komodo dragons are permanently identified using passive integrated transponders (i.e. PIT tags- Trovan ID100) inserted in to their left hind leg.

Mark recapture data then are entered into a central data base (Excel) and then transferred to demographic programs including MARK which will enable estimation of key demographic processes including population growth.

Radio telemetry

Radio telemetry is applied to assess a fine scale spatial ecology, especially to determine movement pattern and home range of Komodo dragon. This method requires transmitters, receivers, and antennas to be able to locate monitored animals. Transmitters are attached to selected animals either by harness, duct taped, or glued to the base of tail as it is considered the best site for placement. Attaching transmitters on juveniles by means of a harness was not feasible, thus use of duct tape or glue are consider the most feasible. Individuals are located either by direct observation or triangulation techniques (White & Garrot 1990). During tracking, certain parameters for habitat type or tree visited by animals recorded as follows; habitat type, tree species, breast height diameter, and tree height. Data will be calculated by means of a computer program ESRI ArcView 3.2 (ESRI 1999) with X-Tolls and Animal Movement program (Hooge et al. 2003).

Nest surveys by implementing transect grids

Field method implemented to inventory Komodo dragon nesting sites is consisted of intensive focal sampling across consecutive transect grids. This method involved multiple observers (5–8) walking at intervals of approximately 25 m apart along a series of parallel transects marked with projected GPS way points. The length and number of transects in each valley was defined by the prevailing topography of the valley. The purpose of these comprehensive transects was to identify and mark (with GPS point) all potential Komodo nesting sites and all megapode nests within each valley up to an elevation of 100 m above sea level. Once all nest are located, following annual monitoring are not require another intensive focal sampling, enough by checking the status of all marked nests and identify whether it is active or not.

Komodo dragons are known to use three types of nest and categorized as follows:

1) Ground nests- consisting of deep sloping horizontal burrows constructed in the ground.

2) Hill nests- typically consisting of large excavations resulting in one or more tiered platforms across the face of the hill. Into these excavations females would dig an egg chamber alongside a number of decoy chambers. These nests are situated in open savanna grassland which covers most low hillsides.

3) Mound nests- Komodo dragons utilized mound nests constructed by orange footed scrub fowl. Active Scrub-fowl mound nests are distinguished from active Komodo mound nests chiefly by the amount of debris and recent diggings that had occurred, particularly during August and September. This is fairly easy to determine as Orange-footed Scrub-fowl nest earlier in the year, with eggs recorded from January until April (Lincoln, 1974), plus megapode nests tend to incorporate vegetative debris into the mound and the chambers into which the birds oviposit (Frith, 1956; Jones et al., 1995).

Komodo dragon nests are identified by the presence of large chambers up to 2 meters long sloping into a nest. These nesting chambers are distinguished from resting chambers (Auffenberg, 1981) by the presence of multiple decoy chambers. Komodo dragon nests are confirmed active by the presence of recent digging activity by females (beginning in August) or by repeated observations of the female in association with the nest (August through November). Inactive Komodo dragon nests are confirmed by the absence of recent digging activity or female guarding the nest throughout the nesting season. These inactive nests are known to be used by Komodo dragons due to observations by park rangers (prior to the current season) of female digging and nest attendance activities or due to changes in structural characteristics, particularly the size and number of chambers in the nest. The density of active and inactive Komodo dragon nests is analyzed by dividing total nest number for each category by the area searched as calculated by shape polygons using Arc view 3.1 (ESRI). As an index of nest dispersion, the mean nearest neighbor measurement was calculated between valleys as the average distance to the closest neighbor from each active nest in a survey location.

Komodo dragon active nests monitoring should be undertook during early nesting season (August-September) each year. Monitored nests on Komodo and Rinca can refer to Jessop (2007) data.

Nest fencing

Komodo dragon nests are confirmed active by the presence of recent digging activities by females (beginning in August) or by repeated observations of the female in association with the nest (August through November). Active Komodo nest will be guarded by associated female that laid her eggs in the nest for about 3-4 months (August-December). Once the female that guarding active nest is leaving, by late December, nest need to be fenced by 1,5 meter metal-sheeting plate. This fence is constructed to avoid emerged hatchling escapes before counted and measure, also to give protection to the hatchlings from being attacked by predators. Once nest-fence established, the nest should be checked twice daily. When hatchlings emerge from nest, all hatchlings are needed to capture, measure, and permanently marked. After all emerged hatchlings are released from the nest, to assess fecundity nest should be dug, to find and count the number of eggs and compared to number hatchlings that emerged.

Genetic and health studies

For further study, sex ratio and age specific survivorship of Komodo dragon by mean of genetic analysis and long term mark recapture method is highly recommended. Blood samples (300 µl) are collected from the caudal vein of new individuals (please refer to previous work of Jessop et al 2002-2006 of CRES ZSSD to identify marked and unmarked animals), using a 21 g needle and 3ml syringe, to enable further genetic sexing analysis of dragons. These blood samples should be stored and transported by staff of Balai Komodo National Park prior to further analysis at Genetic lab in Indonesia, i.e. LIPI.

Individual and population health of Komodo dragons is an important point that also necessary to monitor. Parasitological condition should be monitored by mean of fecal analysis and direct observation for thick that exists on the Komodo skin.

2. Prey density and diversity among four islands within Komodo National Park.

Assessment of density in large prey

Three species of large ungulate prey including the Timor deer (Cervus timorensis florensis), Wild pig (Sus scrofa) and Water buffalo (Babulus bubalus) are monitored by implementing indirect survey techniques (reviewed in Thompson et al. 1998) based on faecal counts: estimates from these techniques should be less influenced by the tendencies of prey to avoid people or be missed in forest. Counts of the standing crop of ungulate pellets or faecal pellet groups have been widely used to estimate the relative or absolute abundance of many ungulate species (Bennett et al., 1940; White, 1992; Thompson et al., 1998).

An indirect index of prey density is calculated using pellet counts on linear transects. Within each site between 20 and 49 permanent linier transects were randomly positioned and orientated (refer to Jessop 2007). Pellet groups are tallied from 30 sample plots placed across each 150 meter long transect. Each plot is a circle with a radius of 1 m and encompasses an area of 3.14 m2. All deer pellet groups within the plot were recorded. A group is standardized as a dense aggregation of pellets exceeding 40 pellets; groups below 40 are counted as individuals then divided by the mean pellet count (taken from counting 60 intact pellet groups). Pellet groups that are greater than 50% inside the plot area are counted as an entire group. To standardize seasonal differences, in pellet density it is important to conduct all pellet surveys across the 10 sites in late September and early October of 2006.

To calculate means bootstrapping technique is necessary to operate (Manly 1997), 95% confidence intervals (‘CI’) and CVs for the plot-based estimates of faeces abundance (per ha) for each large prey species at each site. Bootstrap estimates were based on 10 000 samples. The CV was:

Assessment of density in small prey

Rat (Rattus ratus)

Rats are captured by operating Elliot traps spaced at 10 meter intervals along randomly positioned trap-lines at each study site. Trap-lines placed with at least 200 m apart to reduce the possibility of animals being sampled by more than one trap-line. Trapped rats are individually identified, measured and released at the point of capture. Newly captured animals were given a unique mark by ear tagging. On their first capture during a trapping session animals are weighed and sexed. The head and body length is taken as being from the tip of the nose to the middle of cloaca, the tail length from the middle of cloaca to the tip of the tail. Tails with a terminal scar were assumed to be shortened and were excluded from measurement.

To assess differences in prey density among the five islands the plot counts, distance and mean number of rats per trap night should be undertook. The four sites on both Komodo and Rinca islands are pooled and used to infer a total island sample. Comparison of island means for each of the five species are analyzed by parametric and non-parametric analysis of variance depending on data meeting the assumptions of normality and homogeneity of sample variance. To discriminate significant differences among islands appropriate post- hoc methods (Tukey’s test and Dunn’s method) was used to identify subgroups.

Tokay Gecko (Gekko gecko)

Gekko gecko are monitored by using line transect technique. During the day prior to each survey mark out transect lines with fishing line marked for every five meters with flagging tape. All gecko surveys begin after dark, using powerful head-mounted 6V spotlights conducted by three people. Geckos counted by slowly walking along the transect line, searching every tree, shrub and vine mat within sight, on both sides of, and directly above the string. As often as possible walk off the transect line a few meters on either side; to give a wider range of viewing angles and the ability to more carefully search within trees directly above the transect line. When a gecko is sighted, measure the perpendicular distance at ground level directly beneath the gecko to the transect line (to within 0.1 m), and estimate the geckos height above ground to the nearest meter.

To estimate the density of geckos, use conventional Distance sampling method analysis. In this method the number of geckos located within the survey area are modelled as a function of perpendicular distance of the detected lizard from the line (Buckland et al. 2001). Data analysed using the program DISTANCE 4.2 release 1 (Buckland et al. 2001). DISTANCE is freeware available at http://www.ruwpa.st-and.ac.uk/distance/, and is widely used for the analysis of line transect data.

3. Assessment of habitat and other terrestrial key with focus on endangered species

Vegetation monitoring

Vegetations are monitored by plot method; permanent plots are placed in each represented habitat composition on each of 10 study sites. A 20×20 m permanent plot is established to estimate tree density with number of plots repetition depends on habitat size. Seedlings and saplings should be estimate by established subplots. Grass as the main food for herbivore animal is also monitored by using similar plot method. Density of grass is estimated by measuring 10 1×1 meter permanent plots in each of 10 study sites. Morphological characters like tree and grass species, DBH, height and canopy cover are measured by plastic measuring tape.

Active nest of Orange-footed Scrub-fowl (Megapodius reindwardt)

Orange-footed Scrub-fowl build conspicuous incubation mounds (Jones et al. 1995, Palmer et al. 2000). For each mound located, we recorded the location, elevation, status (active or inactive), overhead vegetation cover (0-25, 26-50, 51-75, or 76-100%), adjacent vegetation type (open forest, closed forest, savanna, or grasslands), and soil type (loamy, sandy, rocky, or gravelly). Inventoring incubation mounds is implemented by intensive focal samplings across consecutive transect grids with multiple observers (5 – 8) walking at 25-m intervals along parallel transects. The length and number of transects in each valley were determined by topography. Following annual monitoring will not require another intensive focal sampling, enough by check the status of all marked nest and identify whether its active or not. Structural characters of each mound are also need to recorded, including length, width, height, number of chambers excavated in each mound, and adjacent habitat type.

Active scrub-fowl mounds are those used for breeding during breeding season, and are distinguished from inactive mounds by evidence of recent digging, incorporation of new leaf litter, and, in some instances, the presence of adults at a nest or the presence of their tracks. Inactive mounds are those not being used in that breeding season and ranged from mounds with egg chambers containing old leaf litter to flattened mounds with no evidence of activity and covered in grass. The density of active Orange-footed Scrubfowl nests is calculated by dividing total nest number for each category by the area searched as calculated by shape polygons using Arcview 3.1 (ESRI). As an index of nest dispersion, the mean nearest neighbor measurement is calculated within valleys as the average distance to the closest neighbor from each nest in a survey location.

Due to the difficulty of measuring egg predation directly, we can use an index of predation based on the presence of fresh excavations into the egg chambers of active scrubfowl nests. Predators are identified by their tracks and associated burrowing as either Komodo dragons or wild pigs (Sus scrofa). Excavation by predators is likely to be repaired by scrubfowl, so observed excavations are likely made in the week preceding the survey.

Active nest and direct population counting by vantage count for Yellow-crested Cockatoo (Cacatua sulphurea)

Active nests survey

Nest survey is carried out by systematic searches (Mexquida, 2004) across consecutive transect grids, in which multiple observers (3-5 persons) walked at ≈ 25 meter intervals along parallel transects. The length and number of transects in each valley is defined by the prevailing topography of the valley. Nest searching is carried out across the valleys and including hills up to 60 meters elevation. Active nests are indicated by the present of young(s) in the nest and parents guarding the nesting location.

Once an active nest was located, data should be taken to record characteristics including location (GPS position), elevation, adjacent vegetation type (Open forest, closed forest, savanna), and nesting tree species. Structural characters of each nest are also recorded including tree DBH, tree height, and nest height. Nest locations are marked by means of GPS Garmin Etrex Vista (Garmin). Tree and nest height are measured by means of Suunto Clinometer (Suunto, Finland). To avoid disturbance to the occupants of the nests, nest parameters, i.e width, length, and depth, did not measured. To analyze the spatial distribution pattern, the nests were mapped and nearest neighbor-distances were calculated using the computer program of ArcView 3.1 (ESRI).

Population and Density Estimates

The Yellow-crested Cockatoo population estimate using direct counting of vantage point method in each valley (Bibby et al., 1992). Direct counting of vantage points method is carried out from hills, which provides observers a well suit observation points to observe the whole valleys and feasible to count all individuals sighted. To assess the density of this species within each valley, divide the highest number of the birds counted by the size of the valley. Sizes of the valleys are calculated by creating polygons, based on GPS points that collected during the field study, and covered the entire studied valley area on the map using the computer program of ArcView 3.2 (ESRI).

Monitoring diversity of birds

Inventory and monitoring of avifaunal diversity, can implement intensive focal sampling across permanent line transect. The length of each transect is 1 km, and number of transects in each valley are determined by topography and size of valley. Observer walking slowly across transect line, birds identified base on field guide. Duration of observation, number of observer must be recorded. Observation should be done minimum twice, early in the morning and afternoon (when the birds are most active).

Assessment the presence of exotic/invasive species

Field methods used to inventory presence of exotic/invasive species consisted of intensive focal sampling across consecutive transects grids. This method involved multiple observers (5–8) walking at intervals of approximately 25 m apart along a series of parallel transects marked with projected GPS way points, and then record all the exotic/invasive species (e.g. cactus, dogs, cats). The length and number of transects in each valley was defined by the prevailing topography of the valley. The purpose of these comprehensive transects was to try and identify all presence of exotic/invasive species within each valley. Once exotic species identified and located, further monitoring should be undertook on the same location. Further, elimination efforts should be consider preventing disturbances to the native wildlife and habitat in the Komodo National Park.

Komodo eating Turtle January 14, 2008

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It is well known that Komodo dragon is a carnivore and scavenger. Komodos main prey item is Timor deer (Cervus timorensis), however, this giant lizard is able to feed on various things such as buffalo, lizards, snakes, avians, small mammals (rats), and fishes (Auffenberg, 1981). Auffenberg (1981) also noted that Hawksbil sea turtle (Eretmochelys imbricata) and its eggs is one of Komodos prey among reptiles as their food.
A recent documentary (Aug 17th, 2007) showed three adult Komodo dragons are eating on a young Hawksbill sea turtle. This video is taken in Loh Liang, Komodo island, the biggest island within Komodo National Park.

Video showing adults Komodo dragon eating sea turtle
(sorry due to technical problem, the video can not be shown)


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1. SystematicS and distribution of the komodo dragons

The Komodo dragon, Varanus komodoensis, was described for the first time by Major Peter A. Ouwen in 1912 (Auffenberg & Auffenberg 2002; Dunn 1927). This giant lizard species was placed in the genus Varanus, family Varanidae, order Squamata, Class Reptiles (Mattison 1992). Varanus salvadorii from Southern New Guinea and V. varius from Southeastern and Eastern Australia are believed to be the sister groups of V. komodoensis (King et al. 2002; Molnar 2004). The closest congeneric species occupying the same region is the Monitor lizard, V. salvator salvator (Auffenberg 1981).

Auffenberg (1981) reported that this species was called the “Ora” by the local people of Komodo, Rinca, and West Manggarai. There are several local names described by Auffenberg (1981) from across its distribution in the Lesser Sunda region (see Table 1). The name “Komodo” was taken from the name of the island where the first specimens were taken, and which means “rats” (Dunn 1928).

Table 1. Local names for Komodo dragon

Local name Region

Ora (also hora, lawora) Komodo, Rinca, West Manggarai

Buaya darat (= land crocodile) Komodo, Rinca, West Manggarai

Rugu (= Ora) Central Manggarai

Si (also ugu; = lizard) Central Manggarai

Lio (also ugu, = large monitor) Central Manggarai

Pendugu (Grandfather of Ora) Central Manggarai

Mbou (= Ora) Central Manggarai

Source: Auffenberg 1981

Even though the Komodo dragon is the largest lizard in the world, this species has the smallest range of any large carnivore (King & Green 1999; Mattison 1992; Pough et al. 2001). In the early studies of the Komodo dragon, this species was found in the heart of the Lesser Sunda region on the islands of Komodo, Rinca, Padar, Gili Motang, Gili Dasami (also known as Nusa Kode), and the Western coast of Flores Island (Dunn 1928; Fig. 2.1). Five of the islands are within the boundary of Komodo National Park (PHKA 2000; Fig 1). In studies conducted after 1991, this species could not be found on Padar Island (Ciofi & de Boer 2004; Jessop et al. 2004; Sastrawan & Ciofi 2002).

Figure 1. Distribution of Varanus komodoensis. Grey areas represent the curre distribution; black areas represent areas that were identified as part of the distribution by Auffenberg (1981); hatched areas indicate where V. komodoensis have been reported by villagers.

Source: Redrawn from Sastrawan & Ciofi 2002.

2. Present status of the komodo dragonS

Based on population surveys conducted by the park authority, there were approximately 2405 Komodo dragons living within Komodo National Park in 1998 (PHKA 2000, unpublished report). Ciofi and de Boer (2004) estimated that the population density of dragons on Flores was more than 60% lower than that reported for Komodo National Park (Table 2). Jessop et al. (2006 in press) estimated that the dragon population on Gili Motang Island has the lowest density of dragons of all the inhabited islands within the park (see Table 2).

The disappearance of resident Komodo dragons on Padar Island probably stemmed from the decline of Timor deer (Cervus timorensis) populations due to illegal hunting (Ciofi 1999; Ciofi & de Boer 2004). Pet and Subijanto (2001) reported that there were at least 3 cases (37.5 %) of deer hunting in Komodo National Park that had been sent to court during 2000-2001. Ciofi et al. (2002), Ciofi and de Boer (2004), and Primack (2004) stated that fragmentation and habitat disturbance as a result of the high population growth of humans are the main factors affecting Komodo dragon populations on Flores.

Table 2. Average density of Varanus komodoensis in Komodo National Park (KNP) and Flores Island.

Location Population density Number of sites

KNP 1 / 33.25 km 4

Komodo 13.7 ± 1.67 / km

Rinca 19.6 ± 3.13 / km

Nusa Kode 5.1 ± 0.61 / km

Gili Motang 3.2 ± 0.23 / km

Flores 1 / 170.0 km 7

Source: Modified from Ciofi & de Boer 2004; Jessop et al. 2006 unpublished data.

Even though the Komodo dragon is not threatened by the leather trade, like the congeneric Water Monitor (V. salvator), and is considered ‘dangerous’ to humans (King et al. 2002; Shine et al. 1996; Ellis 1998), hunting and trade in this species has been occurring for a long time. Since the 1930’s Komodo dragons and their eggs have been hunted illegally for zoo collections and for traditional medicine (Primack et al. 1988). Hien (2003) reported that the local people of Riung, Northwest Flores, claimed that they once illegally caught 50 live specimens of the Komodo dragon for a foreigner. However, the widespread hunting and trading of other reptiles including varanids, for their skins and for food (e.g. Shine et al. 1996) should be considered a potential threat to the Komodo dragon.

The Komodo dragon is protected by international conventions; it is listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and is classified by the International Union for the Conservation of Nature Resources (IUCN) as “vulnerable” due to its demographic decline and limited distribution (Ciofi et al. 2002). The World Conservation Monitoring Center (WCMC) also listed the Komodo dragon as “Rare” due to it’s restricted distribution (Ellis 1998). This species is protected in Indonesia under Act no. 5, on Conservation of Biological Resources and Their Ecosystems,1990,; and Government regulation no. 7, on Protected Wild Flora and Fauna, 1998. Primack (2004) included the Komodo dragon in his discussion on “conservation priorities” as he considered that this species met all the criteria of distinctiveness, endangerment, and utility

Biology, ecology, and reproduction of the Komodo dragonS

Compared to other species in the family Varanidae, Varanus komodoenis has an extremely large body size. Adults can reach up to 304 cm in total body length and weigh up to 81.5 kg (Jessop et al. 2006 unpublished data). Sastrawan and Ciofi (2002) recorded the largest Komodo dragon in their field study as being about 300 cm in length and weighing about 69 kg. Auffenberg (1981) recorded his largest specimen caught as being 260 cm in length and 54 kg in weight. This is similar in length to the largest specimens of its sister species, the Papuan monitor V. salvadorii, which reached about 265 cm in length (Horn 2004). Another large varanid species, occuring on the islands of Java, Bali and throughout Lesser Sunda region, V. salvator may reach up to 218 cm in length and weigh up to 25 kg (Gaulke & Horn 2004; Horne & Gaulke 2004).Hatchlings of V. komodoensis average 30.4 cm in total length and 0.08 kg in weight, and are considerably longer at hatching than other large varanid species (Auffenberg 1981). Ciofi (2004) recorded that hatchling V. komodoensis average 42 cm in total length and 0.10 kg in weight. Hatchling V. salvadorii possibly reach up to 49 cm in total length and 0.55 kg in weight (King & Green 1999).

Komodo dragons can be found from sea level up to about 800 meters in altitude, mainly in tropical dry and moist deciduous monsoon forests (Ciofi 2004). Indeed, this species is generally distributed over entire islands within KNP and western coastal on Flores but is rarely found above 500 meters (Auffenberg 1981).

All varanids are insectivores or carnivores. Unlike other varanids that rely on smaller prey species, Komodo dragons are able to feed on larger vertebrate species, such as the Timor Deer (Cervus timorensis), water buffalo (Bubalus bubalis), or small wild boars (Sus scrofa). Adult Komodo dragons mostly rely on a sit-and-wait hunting strategy to catch their prey (Auffenberg 1981; Green et al. 1990; King & Green 1999; Pough et al. 2001). Hatchlings and juveniles, however, feed on a diverse diet of insects, small lizards, snakes and birds, and use more active hunting strategies than adults (Auffenberg 1981; Ciofi 1999; Mattison 1992).

Female Komodo dragons are known to breed when they reach a body weight of around 20 kgs (King & Green 1999). Females begin nesting in August, as determined by the presence of recent digging activity on the nest, or by repeated observation of individuals in association with the nest during the nesting period. The nesting period is from August through November, with egg deposition occurring in September (Ciofi 1999; Jessop et al. 2004). Up to 38 hatchlings will emerge from the nest at the beginning of the dry season (Auffenberg 1981; Jessop et al. 2006 unpublished data). This early life-stage is dominated by high mortality. Cannibalism among Komodo dragons has been observed and was calculated to comprise 8% of adult dragon scats (Auffenberg 1981). Cannibalism has also been recorded in other Varanids, such as V. griseus, V. gouldii and V. gigantheus (King & Green 1999).

4. Biology and ecology of juveniles

Generally, mortality in lizards is highest during the first phase of their life because they are more vulnerable to predation (Mattison 1992). Poor maternal body condition and stress can decrease the dispersal tendency of juveniles (Meylan et al. 2002). Typically, natural populations show substantial variation, in locomotor performance and body size, which is related to offspring survivorship (Clobert et al. 2000). Thus, the growth and survivorship of offspring in reptiles is greatly affected by the animal’s environment (i.e. Brockelman 1975; Gans & Pough 1982).

Incubation temperature is known to contribute greatly to the quality of emerging hatchlings and affects their survivorship. Cold temperature during incubation can negatively effect hatchlings and hot temperatures can positively effect hatchlings (Elphick & Shine 1998; Phillips & Packard 1994; Qualls & Andrews 1998). This pattern is complex, however, as higher incubation temperature will result in earlier hatching but produce lighter and smaller hatchlings than lower temperature, which produce larger offspring that tend to survive better (King & Green 1999). Du and Ji (2003) reported that moderate temperatures produced optimum size, locomotor ability and success of hatchlings in soft-shelled turtle, while Ji and Du (2000) reported a similar pattern in colubrid snakes. In a further study on lizards, the only discernible influence on juvenile phenotypes was their rearing environment (Qualls & Shine, 2000). Brockelman (1975) found that a wide variety of factors can affect optimal body size and the ability to process energy effectively, and these were also affected by the process of competition, which the offspring must face before and during maturity.

Most juvenile reptiles leave the natal area in which they were born and move into new habitats that are not already occupied or to avoid cannibalism by adults (Pough et al. 2001). Greenwood

(1984) noted that natal dispersal among juveniles is also considered as a mechanism to avoid future inbreeding. Heatwole (1976) and Sarno et al. (2003) described natal dispersal as being driven by the competition for food resources and territories with adult.Dispersal is a mechanism for survival and is a consequence of permanent movement away from the natal site (Brown & Downhower 1988). Animals will exploit available resources once they are out of their natal sites (Greenwood & Swingland 1984). Pelletier et al. (2003) described how immature turtles immediately swam towards the ocean and steadily traveled long distances once released into the water. Hatchling of varanids tend to climb trees and spend most of their time in the upper strata of trees once they emerged from the underground nests (Auffenberg 1981; Bohme et al. 2004; Ciofi 2004; King & Green 1999).

5. Previous ecological studIES on the KOMODO DRAGONS

The first scientific study on the Komodo dragon was conducted by Major Peter A. Ouwen, director of the Zoological Museum in Buitenzorg (now Bogor), Java, in 1912 (Auffenberg & Auffenberg 2002). Ouwen described the species for the first time. Later, Dunn (1927 & 1928) conducted the first significant observations and gave the initial information on the habitat and distribution of Komodo dragons. Auffenberg (1981) contributed to the first comprehensive study on the ecology and behavior of this species. On the basis of 13 months of field observations, Auffenberg (1981) provided the base line information on aspects of the Komodo dragon’s ecology and behavior.

The most recent field study on the Komodo dragon was conducted by Jessop et al. (2006 unpublished data). Since 2002, they undertook a broad scale investigation in the ecologyl and demography of the Komodo dragon, which has provided important information and instigated a program to monitor population trends. Although numerous field studies on the ecology of Komodo dragons have been conducted, yet there are no detailed studies on the ecology on juvenile Komodo dragons (Auffenberg & Auffenberg 2002). Walsh et al. (2002) studied growth in juvenile Komodo dragons, whilst Lemm (2004) reported a relationship between growth and nutritional treatment in captivity. Field and captive studies on this creature, including work on growth, chromosomes, physiology, genetics, ecology and social behaviour, parasites, microbiology, conservation and management, have provided valuable information to science and to ensure effective management of the species (Ciofi et al. 2002). The long-term management and conservation objectives underpinning survival of this species will be to maintain a genetically viable, self-sustaining, and free-living Komodo dragon population. Information on reproduction and broad scale ecology of this species is needed to support the management authority responsible to protect it, and, as pointed out by Jessop et al. (2004), information on offspring survivorship are vital for management planning to ensure the maintenance of this unique species in the wild.