Rhinoplax Vigil Research Articles

Predicting conservation priority areas in Borneo for the critically endangered helmeted hornbill (Rhinoplax vigil)

The critically endangered helmeted hornbill (Rhinoplax vigil) is under threat around its Southeast Asian range due to hunting and habitat loss. Dependant on primary rainforest habitats, the species is thought to be highly sensitive to habitat disturbance. Compounding this is the threat of climate change where equatorial ecosystems, such as those found on Borneo, are predicted to increase in temperature and precipitation. It is therefore important to identify whether the species’ suitable habitats, both now and in the future, are protected from further anthropogenic disturbance. In this study we used species distribution models to assess the extent of suitable habitat for R. vigil across Borneo, an island which has undergone rapid deforestation in recent years, and a stronghold for the species. Using 302 R. vigil occurrence records, four environmental and three land-use cover variables, we modelled R. vigil current habitat suitability, and two future projections under climate change scenarios RCP 4.5 and RCP 8.5 for 2041–2060. Our results suggest that a quarter of Borneo's landmass is currently suitable for R. vigil. However, there is a steep decline in the predicted suitable habitat from 335,963 km2 (current scenario) to 73,170 km2 (future RCP 4.5), to 54,839 km2 (future RCP 8.5). Our model predicts that the amount of suitable habitat protected by current protected areas (PAs) and the planned Heart of Borneo (HoB) initiative will increase under future climate change, with the HoB protecting > 65 % of R. vigil suitable habitat across all projections. This is likely worsened by future land-use change not included in these models, which is a limitation to our study. We therefore encourage the connectivity of lowland PAs, and the continuation of HoB targets to prevent further decline of R. vigil habitat around Borneo. This study provides the first species-specific spatial assessment of the critically endangered helmeted hornbill distribution in response to climate change across current and planned protected regions in Borneo.

Assessing the legal, illegal, and gray ornamental trade of the critically endangered helmeted hornbill.

Monitoring wildlife trade dynamics is an important initial step for conservation action and demand reduction campaigns to reduce illegal wildlife trade. Studies often rely on one data source to assess a species' trade, such as seizures or the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) trade data. Each database provides useful information but is often incomplete. Combining information from multiple sources helps provide a more complete understanding of trade. A recent rapid increase in demand for helmeted hornbill (Rhinoplax vigil) casques (a brightly colored, solid keratinous rostrum) led to its uplisting to critically endangered on the International Union for Conservation of Nature Red List in 2015. However, there is little current information on what factors influence trade trends and what current levels of demand are. We combined data from CITES, seizure records, and previously underused, yet abundant, art and antique auction data to examine the global trade in helmeted hornbill casque products (HHPs). Three decades of auction data revealed that 1027 individual HHPs had been auctioned since 1992; total auction sales were over US$3 million from 1992 to 2021. The number of HHPs auctioned was greatest from 2011 to 2014, just after the global art boom (2009-2011), followed by a decline in volume and price. The auction data also revealed 2 possible markets for HHPs: true antique and speculative, defined by era, price, and trade patterns. Trends in illegal trade matched those of the auction market, but legal trade remained consistently low. Combining data sources from legal, illegal, and gray markets provided an overview of the dynamics of illegal trade in an endangered species. This approach can be applied to other wildlife markets to provide a more complete understanding of trade and demand at the market level to inform future demand reduction campaigns.

Changes in endangered hornbill populations over space and time and potential ecological impacts in peninsular Thailand

Hornbills are particularly important seed dispersers in tropical Asian forests, but most of the species in the region are declining. In addition, long-term data on the extent of the declines and how forest degradation impacts hornbills remain mostly unquantified. Here, we used multi-covariate distance sampling to estimate the densities of hornbills in 2021–2022 in Hala-Bala Wildlife Sanctuary and Budo Su-Ngai Padi National Park protected areas in southern Thailand. These two sites are particularly useful for comparison due to differences in protection levels, with Bala being relatively less disturbed than Budo Mountain and because Bala was surveyed 20 years prior (2001–2002). Fig tree watches were also conducted in 2021–2022 to assess the potential impact of forest disturbance on hornbill visitation rates. Results indicated significant differences in hornbill densities between the two sites. The mean density of the Rhinoceros (Buceros rhinoceros) and Wreathed Hornbill (Rhyticeros undulatus) was 3.2 and 5.1 times higher in Bala than in Budo, while the mean density of the Great Hornbill (Buceros bicornis) was 2.2 times higher in Budo than in Bala. The density of the Helmeted Hornbill (Rhinoplax vigil) was notably lower than other hornbill species. There were also significant changes over the past 20 years in large hornbill densities, with Great Hornbill and Wreathed Hornbill significantly increasing, while the Helmeted Hornbill declined more than 90 %. Also, the probability of hornbills visiting fruiting Ficus trees was higher in the less-disturbed Bala than the Budo Mountain, making hornbills more reliable visitors in the less-disturbed site. We demonstrate the applicability of the multi-covariate distance sampling approach to estimate densities of rare hornbills, the negative impacts of habitat degradation on hornbills and the ecological role they play as seed dispersers. Additional surveys are needed throughout tropical Asia to establish further sites for long-term monitoring, especially in the Sunda region, where the Helmeted Hornbill is under extreme threat.

Evidence for acoustic niche partitioning depends on the temporal scale in two sympatric Bornean hornbill species

AbstractUnderstanding niche partitioning of closely related sympatric species is a fundamental goal in ecology. Acoustic communication space can be considered a resource, and the acoustic niche hypothesis posits that competition between species may lead to partitioning of communication space. Here, we compare the calling behavior of two sympatric Bornean hornbill species—the rhinoceros hornbill (Buceros rhinoceros) and the helmeted hornbill (Rhinoplax vigil)—to test for evidence of acoustic niche partitioning. Both hornbill species emit calls heard over many kilometers and have similar habitat preferences which is predicted to result in interspecific competition. We collected acoustic data on sympatric populations of both hornbill species using 10 autonomous recording units in Danum Valley Conservation Area, Sabah, Malaysia. We found that there was substantial spectral overlap between the calls of the two species, indicating the potential for competition for acoustic space. To test for evidence of acoustic niche partitioning, we investigated spatial and temporal patterns of calling in each species. Both hornbills were strictly diurnal and called throughout the day, and we were equally likely to detect both species at each of our recorders. We did not find evidence of temporal acoustic avoidance at a relatively coarse timescale when we divided our dataset into 1 h bins, but we did find evidence of temporal acoustic avoidance at a finer timescale when we used null models to compare the observed duration of overlapping calls to the expected amount of overlap due to chance.Abstract in Malay is available with online material.

DNA analysis and validation for species identification of seized helmeted hornbill (Rhinoplax vigil) casques

Helmeted hornbills (Rhinoplax vigil, J.R. Forster, 1781) are ‘Critically Endangered’ due to illegal hunting for their casques which are carved and traded for ornamental purposes. DNA species identification techniques can aid enforcement efforts, and validated wildlife forensic techniques for the species identification of R. vigil are needed. Here we tested multiple methods for sampling and extracting DNA from R. vigil casques and a validated a previously published assay using cytochrome B (cytB) primers to identity species and origin of traded casques. Phenol-chloroform: isoamyl alcohol extractions resulted in samples with higher quantity and quality of DNA than those extracted using the commercial Qiagen DNeasy Blood and Tissue kit. Samples collected from the caudal side of the casque yielded higher DNA quantity and quality than rostral and lateral sides, regardless of sampling method. We then assessed the repeatability, reproducibility, robustness, sensitivity, specificity, and phylogenetic resolution of a previously published species identification assay. We confirm the ability of this method to phylogenetically distinguish between R. vigil and closely related hornbills with high bootstrap support (99%). We also report the first genetic evidence of illegally traded R. vigil in Hong Kong using confiscated casques and provide more reference samples of R. vigil for future work. Overall, we provide multiple protocols for sampling and extracting DNA, and a validated species identification assay for amplifying DNA from R. vigil casques with potential to aid law enforcement in illegal wildlife crimes.

Three birds with one stone? Sex ratios of seized critically endangered helmeted hornbill casques reveal illegal hunting of males, females and juveniles

AbstractHunted wildlife can often be used to answer questions about wild individuals. Sex ratios of hunted individuals can be important for understanding changes in population demographics and viability. Here we determined the sex ratio of the illegally hunted helmeted hornbillRhinoplax vigil, a critically endangered species from Southeast Asia, to examine their vulnerability to hunters. Using casques seized in Hong Kong SAR between 2012 and 2016, we identified the sex of seized individuals using morphological and molecular methods as well as discriminant analysis. AsR. vigilfemales can spend up to 6 months of the year sealed into tree cavity nests, they are reliant on males for food. The unique breeding ecology of this elusive species means that males are more likely to be observed than females throughout the year. These behavioural differences mean that there are several potential outcomes which may be observed in the sex ratio of the seized casques, depending on hunting strategies. Our results suggest that sex identification is possible via visual inspection of the gular skin colour and beak‐tip markings, but when these are not available, genetic methods or morphological measurements can be used. Our findings also indicated a primarily male‐biased sex ratio across the seizures; however, females, as well as juveniles, were also present in seizures. Although removing one sex from the wild can cause shifts in demographic dynamics over time, illegal and unsustainable hunting of any measure of a critically endangered species will ultimately heighten its risk of extinction. These methods and results are useful to conservationists and researchers interested in further study of hornbill populations and their viability and are ultimately important for the conservation and management of this critically endangered species.

Late Pleistocene and Early Holocene Birds of Northern Vietnam (Caves Dieu and Maxa I, Thanh Hoa Province)—Paleornithological Results of the Joint Bulgarian-Vietnamese Archaeological Expeditions, 1985–1991 (Paleoavifaunal Research)

The examined material (207 bones and bone fragments) of 53 avian taxa from two human cave dwellings is dated between 24,000 ± 1000 BP and 9400 ± 100 BP. It reveals that 49.0% of the bird species/taxa disappeared from the recent bird fauna of the Thanh Hoa Province; 39.6% disappeared from the recent bird fauna of North Vietnam (except Thanh Hoa Province); 33.9% disappeared from the recent bird fauna of Vietnam (except North Vietnam); 28.3% are not extant in the recent bird fauna of Indochina (except Vietnam); and 52.8% disappeared from the recent bird fauna of Southeast Asia (except Indochina). This suggests more considerable influence of the Late Pleistocene climatic events on the environment and bird fauna than previously accepted in the Eastern part of the Indochinese peninsula in the last 24–millenia. The gallinaceous birds are best represented. Of the 39 Southeast-Asian species, 18 species/taxa (46.2 percent) are Galliforms. They consist of 34 percent of all bird taxa recorded in both caves. Four categories of the IUCN Red List have been represented among the established birds in the sites: LC—28, NT—7, VU—2 (Buceros bicornis and Rhyticeors undulates), and CR—2 (Lophura edwardsi and Rhinoplax vigil).

DNA Species Identification for Seized Helmeted Hornbill (Rhinoplax Vigil) Casques: Standardisation and Validation

DNA Species Identification for Seized Helmeted Hornbill (Rhinoplax Vigil) Casques: Standardisation and Validation

DNA recovery and analysis from helmeted hornbill (Rhinoplax vigil) casques and its potential application in wildlife law enforcement

Since 2011 the demand from China for the keratin casque from helmeted hornbills, so called red ivory, has increased significantly according to recent studies and has the potential to drive this species to extinction. Wildlife DNA Forensics is the field of science tasked not with expanding academic knowledge but with providing evidence for court in relation to wildlife crimes or for providing robust intelligence information to enforcement agencies in relation to trade routes for illegal wildlife products. In this pilot study, we examine the potential to recover DNA from the casques of the helmeted hornbill and evaluate how this genetic information could be used to better inform investigations into the illegal trade of helmeted hornbills.

KEANEKARAGAMAN JENIS BURUNG RANGKONG (Bucerotidae) DI STASIUN PENELITIAN WAY CANGUK TAMAN NASIONAL BUKIT BARISAN SELATAN

The rise of hornbill hunting and deforestation that occurred in Indonesia, especially the island of Sumatra lately, threatening the preservation of these birds in nature. The purpose of this study was to determine thediversity of hornbill species in the Way Canguk Research Station, Bukit Barisan Selatan National Park. The method used in this study is a transect line with a total of 18 line transects. The data obtained was processed using the Shanon wienners diversity index formula, then translated with descriptive analysis. A total of 5 types of hornbills found in these locations are rhinoceros hornbills (Buceros rhinoceros), helmeted hornbills (Rhinoplax vigil), wreathed hornbill (Rhyticeros undulatus), bushy crested hornbill (Anorrhinus galeritus) and white crowned hornbill (Berenicornis comatus), with a species diversity index value of 1.00 included in the low category and the evenness of the species is a stable with an evenness index value of 0.62. The highest abundance of hornbills is (Anorrhinus galeritus) a beside that hornbills can be found in almost all transect lines.

DNA Recovery and Analysis from Helmeted Hornbill (Rhinoplax Vigil) Casques and its Potential Application in Wildlife Law Enforcement

DNA Recovery and Analysis from Helmeted Hornbill (Rhinoplax Vigil) Casques and its Potential Application in Wildlife Law Enforcement

DNA Recovery and Analysis from Helmeted Hornbill (Rhinoplax Vigil) Casques and its Potential Application in Wildlife Law Enforcement

DNA Recovery and Analysis from Helmeted Hornbill (Rhinoplax Vigil) Casques and its Potential Application in Wildlife Law Enforcement

Ethnoornithological study in selected villages of Riau Province, Indonesia

Abstract. Elfis, Titisari PW, Suharni N, Khairani, Janna N, Permatasari T, Chahyana I. 2020. Ethnoornithological study in selected villages of Riau Province, Indonesia. Biodiversitas 21: 1645-1652. Riau Province, along the central-eastern coast of Sumatra, is an area of high bird diversity. The purpose of this study is to document and analyze the ethnoornithological local wisdom of some selected villages and use it to develop a strategy for biodiversity conservation in Riau. The method used in this research involved direct observation of some areas that have local accumulated natural history knowledge and interviews with selected informants of the local community. Some bird species were found to be central to the local culture, and these included the Punai Saluang/Sumatran Green-pigeon (Treron oxyura Temminck), Serindit Melayu/Blue-crowned Hanging Parrot (Loriculus galgulus Linnaeus), Bubut/Greater Coucal (Centropus Sinensis Stephens), and Rangkong Gading/Helmeted Hornbill (Rhinoplax vigil Forster). These bird species are used in traditional medicine, rituals and symbols in Riau Province. Serindit Melayu/Blue-crowned Hanging Parrot is a symbol of the Malay community in Riau and averts evil in the village of Gema. Rangkong Gading/Helmeted Hornbill body parts are used in ritual treatment to cure various diseases by the TalangMamak Tribe in Rantau Langsat. Punai Saluang/Sumatran Green-pigeon is used as a metaphor in folk literature of the Malays in the Pelalawan area, and Bubut/Greater Coucal (Centropus sinensis Stephens) body parts are used as traditional medicine by the Malays in Kuok Village. There are several aspects that need to be studied further to conserve these birds, including the ecology, reproduction, and behavior aspects. Through preservation of these ethnoornithological rituals and education of the younger generation, these and other species of birds can be better sustained in and around the culture of Riau society.

A molecular genetic approach for sex determination on helmeted hornbill (Rhinoplax vigil) casque: a forensic casework

Helmeted Hornbill(Rhinolax vigil)is the only hornbill that equipped with solid casque made from keratin for both males and females. The demand for casque in the black market was huge and resulted in IUCN status leaped up from vulnerable to critically endangered. We received a total of 68 confiscated helmeted hornbill casques. As part of the casework and the objectives of the study, we determined to reveal the sex status of those casques and the best methods to work with keratinous material. Molecular methods to determining sex in birds rely on the CHD gene located on male and female chromosomes ZZ and ZW, respectively. We optimized laboratory protocols for genetic sexing using three independent sets of primers P2/P8, 2550F/2718R, and CHD1F/CHD1R to amplify regions of the sexlinked CHD-Z and CHD-W genes. The CHD1F/CHD1R determined sex 80.88% of samples. The 2550F/2718R were quite successful, sexing 51.47% of samples. In contrast, the P2/P8 only identified the sex around 20.58% of samples. These results showed that CHD1F/CHD1R works the most effective for sexing the casques with 52.9% females, 27.9% males, and 19.1% unidentified. Therefore, the most accurate and suitable primers are CHD1F/CHD1R, 2550F/2718R, and P2/P8, respectively for keratinous samples.

Limited directed seed dispersal in the canopy as one of the determinants of the low hemi-epiphytic figs' recruitments in Bornean rainforests.

Ficus species are keystone plants in tropical rainforests, and hemi-epiphytic figs play a notably important role in forest ecosystems. Because hemi-epiphytic figs have strict germination requirements, germination and establishment stages regulate their populations. Despite the ecological importance of hemi-epiphytic figs in the rainforests, seed dispersal systems by fig-eating animals under natural conditions remain unknown because of the difficulty in tracing the destiny of dispersed seeds in the canopy. Therefore, seed dispersal effectiveness (SDE) has never been evaluated for hemi-epiphytic figs. We evaluated the SDE of hemi-epiphytic figs using qualitative and quantitative components by three relatively large-sized (> 3 kg) arboreal and volant animals in Bornean rainforests that largely depend on fig fruits in their diets: binturongs Arctictis binturong, Mueller’s gibbons Hylobates muelleri, and helmeted hornbills Rhinoplax vigil. The SDE values of binturongs was by far the highest among the three study animals. Meanwhile, successful seed dispersal of hemi-epiphytic figs by gibbons and helmeted hornbills is aleatory and rare. Given that seed deposition determines the fate of hemi-epiphytic figs, the defecatory habits of binturongs, depositing feces on specific microsites in the canopy, is the most reliable dispersal method, compared to scattering feces from the air or upper canopy. We showed that reliable directed dispersal of hemi-epiphytic figs occurs in high and uneven canopy of Bornean rainforests. This type of dispersal is limited to specific animal species, and therefore it may become one of the main factors regulating low-success hemi-epiphytic fig recruitment in Bornean rainforests.

Distribution of Hornbills in western Sarawak and the Way Forward for Their Conservation in Sarawak

There are eight species of hornbills in Borneo. However, little is known on their distribution and ecology in western Sarawak. Their large size requires habitats that consist of large forest patch with large fruiting trees for feeding and nesting. They have an important ecological niche as seed dispersers throughout the tropical rainforests of South East Asia. This study briefly describes the distribution of hornbills in Totally Protected Areas (TPA) within western Sarawak based on data collected by Sarawak Forestry Corporation from 2013‒2016. We discuss the hornbill species distribution and the species area relationship within western Sarawak. The Rhinoceros Hornbill (Buceros rhinoceros) recorded the highest occupancy value (psi) and probability of detection (p), followed by the Black Hornbill (Anthracoceros malayanus) and the Bushy-crested Hornbills (Anorrhinus galeritus). The Helmeted Hornbills (Rhinoplax vigil) appears to occur in fewer TPA within western Sarawak. A long-term conservation plan is required to ensure the sustainability of the hornbill population through extending protected areas and connecting forest patches. In light of this, the research and conservation needs for these species in Sarawak are highlighted to ensure their long-term survival in the wild.

Sumatran Hornbills in Fragmented Forest Areas in Oil Pam Plantation in South Solok, West Sumatra

A study on hornbill populations in fragmented forest areas within oil palm plantations in Tidar Kerinci Agung (TKA) Company, West Sumatra was carried out from July to August 2015 in 60 Hectare fragmented forest areas. The objective of this study was to document hornbill species richness using the transect method on three main lines along two km and using call recognition for population census of hornbill. During the study, we recorded 82 individuals of eight species after 60 km walk. We encountered using two methods (Sighting and Calls Methods); Anorrhinus galeritus twenty-one encounters, Berenicornis comatus single encounter, Rhabdotorrhinus corrugatus two encounters, Rhyticeros undulatus two encounters, Anthracoceros malayanus sixteen encounters, Anthracoceros albirostris seven encounters, Buceros rhinoceros thirty-one encounters and two encounters of Rhinoplax vigil.

Identification Characteristics of Natural and Imitation Hornbill Ivory

Natural hornbill ivory (from the bird Rhinoplax vigil) is a rare gem material, and in recent years imitations and composites have appeared on the Chinese gem market. In this study, the gemmological properties of these products were systematically investigated using microscopic observation, FTIR spectroscopy and UV fl uorescence. The key identifi cation features for natural hornbill ivory are a layered structure with minute pigmented dots, which were not present in polymer resin imitations. Air bubbles were detected in both the imitations and in composites made from hornbill ivory and resin. FTIR spectroscopy is useful for confi rming the presence of resin.

Basic conservation approaches and the fate of hornbills in Thailand: a prototype for future bird–people relationships

Hornbills, the largest birds of Asian tropical forests, are ideal flagship species. Budo Mountain supports six sympatric hornbill species, of which Rhinoceros Hornbill Buceros rhinoceros and Helmeted Hornbill Rhinoplax vigil are locally endangered. Because hornbills rely on a cavity in a large tree for nesting, the combination of forest encroachment and poaching could extirpate them from Budo. To increase and sustain hornbill populations, we set two phases of approach, immediate and long-term. Since 1994, 50 ex-poachers and/or illegal loggers from 13 villages around Budo were persuaded to participate in research and conservation programs together with urban people. These were based on hornbill nest adoption, with 1,774 nest-years of adoption now accrued that provide an essential data base and major source of funding. Within 90 km2 of Budo rainforest, villagers have located 189 nest trees, among which an average of 38 nests were used annually. Despite difficulties within the area, including natural problems and situations of social unrest, a cumulative total of 1,170 nest-cavity-years have been recorded by the villagers, and at least 490 chicks have fledged. The program is considered successful in terms of poaching eradication and has led to the establishment of the Budo Hornbill Conservation & Education Center in 2004 on a piece of land donated by a villager’s family. The Center provides educational and conservation lessons to schoolteachers, children, teenagers and villagers in the surrounding area for approximately 400 individuals per year, and could be a model for conservation programs of other large but critically endangered bird species.

Density estimates of nine hornbill species in a lowland forest site in southern Thailand

Hornbills are useful indicators of forest condition and human disturbance because they require large tracts of unfragmented forest with large fruiting trees for feeding and nesting. They are relatively large-bodied, which makes them targets for hunting. Density estimates of such species are critical for population monitoring and serve as a baseline against which future changes can be measured. In this study we used variable-width line transect surveys to estimate the densities of nine hornbill species in the Bala portion of the Hala-Bala Wildlife Sanctuary on the Thai–Malaysia border, one of the few remaining areas of lowland forest in Thailand. The hornbill species were: Rhinoceros (Buceros rhinoceros), Great (B. bicornis), Helmeted (B. vigil), Black (Anthracoceros malayanus), Bushy-crested (Anorrhinus galeritus), White-crowned (Aceros comatus), Wrinkled (A. corrugatus), Wreathed (A. undulatus) and Plain-pouched (A. subruficollis). Between January 2001 and April 2002, 11 transects along trails, old logging roads and one paved road were surveyed once per month. A total of 1,261 observations of the nine species were made during the observation period. Estimates for Rhinoceros and Helmeted Hornbill were 2.69 and 1.21 individuals/km2, respectively, and were similar or slightly higher than densities reported elsewhere. Estimates for Great (0.12), Bushy-crested (0.64), Wrinkled (0.08), White-crowned (0.08) and Wreathed Hornbills (0.69) were generally lower than estimates from other areas in the region. It was not possible to obtain density estimates using distance sampling for Black and Plain-pouched Hornbills due to the small number of observations, but our data did suggest that their densities were also low (<0.10 individuals/km2). Potential reasons for differences between this and other areas include a scarcity of lowland habitat, habitat isolation, lower abundance of specific fruit resources and interspecific competition, but these factors require further investigation. Standardization of survey techniques among studies would significantly improve assessments of habitat requirements as well as of the effects of human disturbance on Asian hornbills, most of which are globally threatened. Our study specifically underscores the need for additional research on the Plain-pouched Hornbill, the most threatened of the species studied, as density estimates from elsewhere in its range are lacking, while more generally it highlights the need to investigate the underlying causes of the often substantial variation in hornbill densities among species and sites.