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The Komodo National Park in the Wallacea region is the komodo dragon’s primary habitats. Published report on the herpetofauna of this national park is mostly concentrated in Komodo island. To increase our knowledge of amphibian and reptile communities in Komodo National Park, we conducted a herpetofauna survey in Komodo and Rinca Island and the nearby coastal area to assess diversity and community similarity and developed a complete checklist of the herpetofauna of Komodo National Park. We conducted a Visual Encounter Survey and put glue traps from February-April 2018 at six locations on Komodo Island (Loh Liang, Loh Wau dan Komodo Village) and Rinca Island (Loh Buaya, Loh Baru, and Rinca Village); and three locations on coastal areas of Flores (Labuan Bajo and Cumbi Village) and coastal area of Sumbawa (Sape) adjacent to Komodo National Park. We found seven species of amphibians and 22 species of reptiles and, however, only two species of amphibians and 18 species of reptiles were found in Komodo and Rinca Island. The highest diversity (H’ = 2.14) is in Loh Buaya (Rinca Island), and the highest evenness (E=0.58) is in Loh Baru (Rinca Island). The highest similarity occurs between Komodo Island and Rinca Island (IS = 0.8). Using data from other research, we have compiled a list of four species of amphibians and 39 species of reptiles occurring at three main islands of Komodo National Park: Komodo island, Rinca Island and Padar Island. Keywords: Herpetofauna diversity, Komodo National Park, Lesser Sunda Islands

Large introduced mammalian herbivores, either as livestock or feral populations, can have important effects on vegetation and animals. Introduced herbivores can be of high conservation concern if they impact threatened native species in protected areas. We evaluated temporal and spatial trends in the relative abundance of introduced water buffalo (Bubalus bubalis) and their potential to induce competition-related ecological and demographic effects on native rusa deer (Rusa timorensis) in Komodo National Park and the Wae Wuul Nature Reserve—two protected areas in Eastern Indonesia. To monitor ungulate population abundances and population growth rates of water buffalo and rusa deer, we counted their dung (a validated abundance index in these two species) along 350 permanently marked transects at 11 sites over five islands annually between 2003 and 2018. Water buffalo dung abundance varied with the site, year and their interaction. Water buffalo dung was most abundant within the Wae Wuul Nature Reserve, and their dung abundance varied considerably among sites in Komodo National Park. Water buffalo site-specific dung abundances fluctuated independently over time. In areas of high water buffalo dung densities, rusa deer altered resource use and had lower population densities than sites without water buffalo. Rusa deer dung-based population growth rates were negatively influenced by density-dependent regulation and only weakly by water buffalo dung density. Currently, managers do not control water buffalo in either protected area. Nevertheless, the benefits of control could reduce water buffalo effects on vegetation composition, watercourse integrity, or the potential to transmit disease into native ungulates.

The Komodo dragon (Varanus komodoensis) is an endangered, island‐endemic species with a naturally restricted distribution. Despite this, no previous studies have attempted to predict the effects of climate change on this iconic species. We used extensive Komodo dragon monitoring data, climate, and sea‐level change projections to build spatially explicit demographic models for the Komodo dragon. These models project the species’ future range and abundance under multiple climate change scenarios. We ran over one million model simulations with varying model parameters, enabling us to incorporate uncertainty introduced from three main sources: (a) structure of global climate models, (b) choice of greenhouse gas emission trajectories, and (c) estimates of Komodo dragon demographic parameters. Our models predict a reduction in range‐wide Komodo dragon habitat of 8%–87% by 2050, leading to a decrease in habitat patch occupancy of 25%–97% and declines of 27%–99% in abundance across the species' range. We show that the risk of extirpation on the two largest protected islands in Komodo National Park (Rinca and Komodo) was lower than other island populations, providing important safe havens for Komodo dragons under global warming. Given the severity and rate of the predicted changes to Komodo dragon habitat patch occupancy (a proxy for area of occupancy) and abundance, urgent conservation actions are required to avoid risk of extinction. These should, as a priority, be focused on managing habitat on the islands of Komodo and Rinca, reflecting these islands’ status as important refuges for the species in a warming world. Variability in our model projections highlights the importance of accounting for uncertainties in demographic and environmental parameters, structural assumptions of global climate models, and greenhouse gas emission scenarios when simulating species metapopulation dynamics under climate change., The Komodo dragon (Varanus komodoensis) is an endangered, island‐endemic species with a naturally restricted distribution. Despite this, no previous studies have attempted to predict the effects of climate change on this iconic species. Our modeling shows that without quick action to mitigate climate change impacts on Komodo National Park and on the island of Flores, we risk committing Komodo dragons—a globally iconic species—to extinction.

Increasing wildlife awareness is a commonly used approach in community conservations programs. However, in Indonesia, this approach has rarely been quantitatively evaluated for its effectiveness. I...

Nonconsumptive effects can strongly influence apex predator ecological function. These effects arise because prey often induce costly phenotypic responses to mitigate predation risk. Yet because predator–prey interactions are complex, prey defenses may vary considerably. We investigated if the Komodo dragon (Varanus komodoensis), a reptile apex predator, induced multiscale antipredator responses in key prey, the Rusa deer (Cervus timorensis) and the wild pig (Sus scrofa). To this end, we examined the temporal and spatial partitioning of habitats by predator and prey, determined the size of ungulate groups as a function of risk, and assessed changes in individual behavior of prey individuals exposed to predator kairomones at feeding stations. Komodo dragon, deer, and pig populations exhibited significant, but subtle differences in 3 habitat preferences that otherwise indicated high niche overlap. Komodo dragon predation risk, alongside other commonly considered predictor variables, did not affect deer or pig group size. With the exception of one individual-based vigilance-type behavior in pigs, no other antipredator behavior, including reduced food consumption, significantly varied in the presence of predator odor cue at feeding stations. Overall, our results indicated limited evidence for antipredator behavior and suggested Komodo dragons exert weak nonconsumptive effects of predation in ungulates. However, weak predatory interactions could be beneficial in island ecosystems as it could promote predator–prey coexistence that reduces extinction risk.

Lizards, as predators, can use different prey foraging strategies that are expected to influence daily movement behavior and home range use. Variation in lizard movement behavior can be achieved via frequency changes in movement step lengths and turning angles that can facilitate distinctive prey-searching and foraging strategies. Komodo Dragons (Varanus komodoensis) exhibit a distinct dietary transition at ∼18 kg, where lizards switch from consuming small-bodied and abundant prey species to highly dispersed adult ungulate prey. Our study examined competing models for the relative effects of ontogenetic dietary shift, body mass, sex, time of day, and arboreal habitat use on Komodo Dragon movement behavior (i.e., the proportional use of Levy flight movement steps) and home range area (i.e., 50 and 95% utilization distributions). Model ranking indicated that two models incorporating the proportion of adult ungulates and body mass best explained the increased use of Levy flight movement behavior of Komodo Dragons. Body mass also best explained the increase in the 50 and 95% utilization distribution Kernel home range areas. However, the slope of this relationship was less steep than that predicted by metabolic scaling theory and suggested that attributes specific to Komodo Dragons, or their environment, may attenuate their spatial requirements. This study demonstrates that because of distinct shifts in diet and other activities associated with large body size, Komodo Dragons alter movement behavior and increase their home range area to optimize environmental resource use.

We studied annual trends and characteristics of nesting activities and hatchling production by female Komodo Dragons (Varanus komodoensis) in Komodo National Park, Indonesia between 2002 and 2006. During this period, we recorded 12, 16, 15, 13, and 6 females nesting annually at 42 potential nesting sites. An average female nesting periodicity was estimated at 1.2±0.4 years. This result arose because most females bred annually and some biennially. Some females reused nest sites in successive years while others did not. Nesting females had significantly lower body mass compared to when they were recaptured again in a non-nesting state. All-female nesting activities were conducted within their resident valleys and suggested a strong tendency for spatial fidelity. Komodo Dragons were generally considered solitary nesters as only on one occasion were two nesting females observed to use the same nesting site. On average, 21.0±3.6 Komodo Dragon hatchlings emerged from each nest. We estimated that within the study area, nesting female Komodo Dragons produced between 129.0±21.8 and 344.0±58.16 hatchlings per annum. We discuss the ecological and evolutionary significance of these attributes. However, the main conservation management implications drawn from this study are that there are a low annual number of nesting females and associated hatchling production in Komodo National Park. Hence, a continuation of more extensive nesting surveys could provide a cost-effective and accurate way to gather important long-term demographic information for this species.

The islands of Komodo National Park in the Wallacea region are the habitats of Komodo dragon (Varanus komodoensis). Although the Wallacea islands have lower species richness compared to the other large islands in Indonesia, they are rich in endemics, and the occurrence of invasive species would therefore threatened the ecological, economic and social balance of the regions. Several papers have hinted at the possibility of the invasion of Komodo National Parks by Asian toads, a situation which would potentially affect the survival of the Komodo dragon. To detect the presence of the invansive toad Duttaphrynus melanostictus in Komodo National Park and its surroundings areas we carried out an amphibian survey using a Visual Encounter Survey method during February to April 2018. The surveyed location consisted of two main islands within Komodo National Park (Rinca island and Komodo island), Flores island (Labuan Bajo and Cumbi village) and Sumbawa island (Sape). Two species of amphibians were found in Komodo National Park (Rinca island and Komodo island), while seven species of amphibians were found across all four locations. No D. melanostictus toads were found in Flores (including in Komodo National Park), however the toad was found to be abundant in Sape (Sumbawa island).

Understanding how threatened wildlife can coexist with humans over the long term is a central issue in conservation and wildlife management. Komodo National Park in Eastern Indonesia, harbors the largest extant populations of the endemic Komodo dragon (Varanus komodoensis). Consistent with global trends, this species is expected to be increasingly exposed to human activities and in particular growing ecotourism activities. Here we comprehensively evaluated how human activities affected individual and population level attributes of Komodo dragons. We compared Komodo dragons phenotypic (behaviour, body size, and body condition) and demographic (age structure, sex ratio, survival, and density) responses to variation in human activities across national park. Komodo dragons were found to exhibit pronounced responses to high human activity level relative to sites with low and negligible human activities. Komodo dragons exposed to ecotourism exhibited significantly less wariness, larger body mass, better body condition, and higher survival. These results are entirely consistent with ecotourism activities that provided Komodo dragons with long-term and substantial nutritional subsidies as a consequence of feeding and human food refuse. However, we also noted the potential negative consequences of altered behaviour and adult-biased populations in ecotourism areas which may influence demographic processes through intraspecific competition or predation. To address this issue, we recommend that three management strategies to be implemented in future include: (1) removal of human-mediated nutritional subsidies, (2) alternative ecotourism, and (3) spatial regulation of ecotourism. Furthermore, we advocate the development of approaches to achieve a socio–ecological sustainability that benefits both people and wildlife conservation.

Apex predators can have substantial and complex ecological roles in ecosystems. However, differences in species-specific traits, population densities, and interspecific interactions are likely to determine the strength of apex predators' roles. Here we report complementary studies examining how interactions between predator per capita metabolic rate and population density influenced the biomass, population energy use, and ecological effects of apex predators on their large mammalian prey. We first investigated how large mammal prey resources and field metabolic rates of terrestrial apex predators, comprising large mammals and the Komodo dragon (Varanus komodoensis), influenced their biomass densities and population energy use requirements. We next evaluated whether Komodo dragons, like apex mammalian predators, exerted top-down regulation of their large mammal prey. Comparison of results from field studies demonstrates that Komodo dragons attain mean population biomass densities that are 5.75-231.82 times higher than that of apex mammalian predator species and their guilds in Africa, Asia, and North America. The high biomass of Komodo dragons resulted in 1.96-108.12 times greater population energy use than that of apex mammalian predators. Nevertheless, substantial temporal and spatial variation in Komodo dragon population energy use did not regulate the population growth rates of either of two large mammal prey species, rusa deer (Rusa timorensis) and wild pig (Sus scrofa). We suggest that multiple processes weaken the capacity of Komodo dragons to regulate large mammal prey populations. For example, a low per capita metabolic rate requiring an infrequent and inactive hunting strategy (including scavenging), would minimize lethal and nonlethal impacts on prey populations. We conclude that Komodo dragons differ in their predatory role from, including not being the ecological analogs of, apex mammalian predators.

The roles of density-dependent and density-independent factors in the dynamics of tropical large herbivore populations are poorly understood. Understanding these dynamics is particularly important if the herbivore is prey for an apex predator of conservation concern because a decline in the prey could cause the predator to decline. We tested hypotheses about the roles of density-dependent and density-independent factors in the dynamics of 2 tropical ungulates, Rusa deer ( Rusa timorensis ) and wild pigs ( Sus scrofa ), in Komodo National Park, eastern Indonesia. We counted the dung of Rusa deer and wild pigs (a validated index of abundance for these 2 species) along permanently marked transects at 10 sites over 4 islands annually during 2003–2014 to estimate ungulate abundance. Ungulates were much more abundant on the 2 larger islands compared with the 2 smaller islands, with wild pig dung completely absent from the latter. During our 12-year study, Rusa deer abundance declined slightly on Nusa Kode and Rinca islands, did not change on Komodo Island, and increased on Gili Motang Island. There was a decline in abundance of wild pigs on Komodo Island and an increase on Rinca Island. Annual variation in population growth rate was strongly density-dependent and island-specific for both species, with annual rainfall and vegetation composition being relatively unimportant. Population growth rates of Rusa deer exhibited spatial synchrony, with synchrony declining with increasing intersite distance. Our findings confirm the importance of density dependence in the dynamics of tropical large herbivore populations. However, the strength of density dependence varied between species and spatially. Declines of Rusa deer and wild pigs on the larger 2 islands, which are strongholds of the Komodo dragon, are cause for concern. Continued monitoring of ungulate populations is critical for the conservation of Komodo dragon populations in Komodo National Park. Peran faktor-faktor yang terpengaruh kepadatan ( density-dependent ) dan faktor-faktor yang tidak terpengaruh kepadatan ( density-independent ) dalam dinamika populasi herbivora besar di daerah tropis masih sangat kurang dipahami. Pemahaman terhadap dinamika populasi satwa herbivora sangatlah penting ketika satwa tersebut merupakan satwa mangsa dari predator puncak terutama bagi kelangsungan upaya konservasi satwa predator tersebut. Penurunan populasi mangsa dapat menyebabkan penurunan populasi satwa predatornya. Kami menguji hipotesis mengenai peranan faktor-faktor yang terpengaruh kepadatan dan faktor-faktor yang tidak terpengaruh kepadatan pada dinamika populasi dua satwa mangsa ungulata tropis, yaitu rusa ( Rusa timorensis ) dan babi hutan ( Sus scrofa ) di dalam kawasan Taman Nasional Komodo, Indonesia bagian timur. Estimasi kelimpahan ungulata ini dilakukan dengan cara menghitung kotoran rusa dan babi hutan (indeks kelimpahan yang telah divalidasi pada kedua spesies tersebut) di sepanjang transek permanen pada 10 lokasi penelitian di empat pulau setiap tahunnya dalam kurun waktu tahun 2003–2014. Kelimpahan kedua satwa ungulata tersebut jauh lebih tinggi di dua pulau besar dibandingkan di dua pulau kecil lainnya, di mana pada kedua pulau kecil, kotoran babi hutan bahkan sama sekali tidak dijumpai. Dalam kurun waktu 12 tahun penelitian ini, kelimpahan rusa sedikit menurun di Pulau Nusa Kode dan Pulau Rinca, namun stabil di Pulau Komodo dan meningkat di Pulau Gili Motang. Penurunan kelimpahan babi hutan terpantau di Pulau Komodo, sebaliknya di Pulau Rinca populasinya meningkat. Variasi tahunan laju pertambahan jumlah populasi satwa ungulata tersebut sangat dipengaruhi oleh faktor kepadatannya meskipun untuk kedua spesies ungulata ini sangat spesifik pada setiap pulau, di mana curah hujan tahunan dan komposisi vegetasi relatif tidak memberikan pengaruh. Laju pertumbuhan populasi rusa menunjukkan adanya perbedaan berdasarkan lokasi, dengan kecenderungan penurunan seiring dengan bertambahnya jarak antar lokasi penelitian. Hasil penelitian membuktikan pentingnya faktor yang tergantung kepadatan dalam dinamika populasi herbivora besar di daerah tropis, meskipun terdapat variasi antar spesies dan lokasi. Penurunan populasi ungulata di kedua pulau besar yang menjadi habitat utama biawak komodo ini menjadi hal penting untuk diperhatikan. Pemantauan secara kontinyu terhadap populasi satwa ungulata sangatlah penting bagi kelangsungan kegiatan konservasi biawak Komodo di Taman Nasional Komodo.

We document six observations of an aquatic behaviour used by rusa deer (Rusa timorensis) to delay an imminent attack from Komodo dragons (Varanus komodoensis). This unusual behaviour arose after rusa deer fled into the nearby seawater following an attack from a solitary Komodo dragon. Once in the sea, rusa deer remained relatively stationary by standing in shallow water (

The population dynamics of island species are considered particularly sensitive to variation in environmental, demographic and/or genetic processes. However, few studies have attempted to evaluate the relative importance of these processes for key vital rates in island endemics. We integrated the results of long-term capture–mark–recapture analysis, prey surveys, habitat quality assessments and molecular analysis to determine the causes of variation in the survival rates of Komodo dragons Varanus komodoensis at 10 sites on four islands in Komodo National Park, Indonesia. Using open population capture–mark–recapture methods, we ranked competing models that considered environmental, ecological, genetic and demographic effects on site-specific Komodo dragon survival rates. Site-specific survival rates ranged from 0.49 (95% CI: 0.33–0.68) to 0.92 (0.79–0.97) in the 10 study sites. The three highest-ranked models (i.e. ΔQAICc < 2) explained ∼70% of variation in Komodo dragon survival rates and identified interactions between inbreeding coefficients, prey biomass density and habitat quality as important explanatory variables. There was evidence of additive effects from ecological and genetic (e.g. inbreeding) processes affecting Komodo dragon survival rates. Our results indicate that maintaining high ungulate prey biomass and habitat quality would enhance the persistence of Komodo dragon populations. Assisted gene flow may also increase the genetic and demographic viability of the smaller Komodo dragon populations.

Multidisciplinary conservation initiatives are increasingly advocated as best practice for recovering endangered species. The Komodo dragon Varanus komodoensis is the world's largest lizard, of prominent conservation value as an umbrella species for protection of south-east Indonesian ecosystems. Komodo dragons have faced multiple human-related threat processes in the past 30 years and are listed on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and considered Vulnerable according to the International Union for Conservation of Nature Red List. We report on a protection programme conducted from 2005 to 2012 in the Wae Wuul nature reserve, on the island of Flores, Indonesia. The Wae Wuul ranger post was completely rebuilt, and community awareness and involvement of local people in habitat-protection schemes were regularly and successfully implemented. Local rangers were trained in wildlife-monitoring techniques. Monitoring results indicated that Komodo dragon densities were lower in Wae Wuul than in the adjacent Komodo National Park; however, a relatively high level of genetic diversity was recorded for this population. Ungulate prey showed a relatively stable prey population density. Community-based initiatives and regular wildlife monitoring are crucial to ensure the persistence of Komodo dragons on Flores. The Wae Wuul protection programme is providing several sustainability indicators by which informed management plans can be designed for long-term conservation of Komodo dragons.

Finding practical ways to robustly estimate abundance or density trends in threatened species is a key facet for effective conservation management. Further identifying less expensive monitoring methods that provide adequate data for robust population density estimates can facilitate increased investment into other conservation initiatives needed for species recovery. Here we evaluated and compared inference-and cost-effectiveness criteria for three field monitoring-density estimation protocols to improve conservation activities for the threatened Komodo dragon (Varanus komodoensis). We undertook line-transect counts, cage trapping and camera monitoring surveys for Komodo dragons at 11 sites within protected areas in Eastern Indonesia to collect data to estimate density using distance sampling methods or the Royle–Nichols abundance induced heterogeneity model. Distance sampling estimates were considered poor due to large confidence intervals, a high coefficient of variation and that false absences were obtained in 45 % of sites where other monitoring methods detected lizards present. The Royle–Nichols model using presence/absence data obtained from cage trapping and camera monitoring produced highly correlated density estimates, obtained similar measures of precision and recorded no false absences in data collation. However because costs associated with camera monitoring were considerably less than cage trapping methods, albeit marginally more expensive than distance sampling, better inference from this method is advocated for ongoing population monitoring of Komodo dragons. Further the cost-savings achieved by adopting this field monitoring method could facilitate increased expenditure on alternative management strategies that could help address current declines in two Komodo dragon populations.