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Description |
Geographic Range [top]
Range Description: This species is endemic to the island of Sumba, Nusa Tenggara, Indonesia. Fieldwork since 1989 previously resulted in a tentative population estimate of 4,000 individuals (based on a density of 2.3 hornbills/km2, and an estimated 1,732 km2 total forest-cover) (BirdLife International 2001). Recent research on the population size needs to be reconciled, as estimates have ranged from 1,650 mature individuals on the whole island (based on delayed maturation and its near absence from small forest patches) (T. OBrien in litt. 2010), to 6,400 individuals solely in the Manupeu-Tanadaru National Park (D. Mulyawati in litt. 2010). Although some areas of habitat are well protected (D. Mulyawati in litt. 2010), the species is likely to be declining overall owing to continued forest loss outside of reserves (T. OBrien in litt. 2010), and future declines may be extremely rapid (Kinnaird and OBrien 2007).
Countries occurrence:
Native:
Indonesia
Additional data:
? Continuing decline in area of occupancy (AOO): Yes
? Extreme fluctuations in area of occupancy (AOO): No ? Estimated extent of occurrence (EOO) - km2: 13100
? Continuing decline in extent of occurrence (EOO): Unknown ? Extreme fluctuations in extent of occurrence (EOO): No
? Number of Locations: 11-100 ? Continuing decline in number of locations: Yes
? Extreme fluctuations in the number of locations: No
? Upper elevation limit (metres): 950
Range Map: Click here to open the map viewer and explore range.
Population [top]
Population: Recent population estimates are difficult to reconcile, ranging from 1,650 mature individuals on the whole of Sumba, to 6,400 individuals in the Manupeu-Tanadaru National Park alone (D. Mulyawati in litt. 2010, T. OBrien in litt. 2010), although another estimate of fewer than 4,000 individuals in total has been given (Burung Indonesia in litt. 2011). A population size of 2,500-9,999 mature individuals is retained here until the differences between these estimates are accounted for.
Trend Justification: Despite the adequate protection of an area of lowland forest in the Manupeu-Tanadaru National Park (D. Mulyawati in litt. 2010), an overall population decline of 30-49% is estimated owing to the extensive and on-going loss and fragmentation of forest habitats outside of the reserve.
Current Population Trend: Decreasing
Additional data:
? Number of mature individuals: 2500-9999 ? Continuing decline of mature individuals: Yes
? Extreme fluctuations: No ? Population severely fragmented: Yes
? No. of subpopulations: 1 ? Continuing decline in subpopulations: Unknown
? Extreme fluctuations in subpopulations: No ? All individuals in one subpopulation: Yes
? No. of individuals in largest subpopulation: 100
Habitat and Ecology [top]
Habitat and Ecology: Despite frequenting a variety of forested habitats, it shows a strong association with low altitude semi-evergreen forest containing large trees with a dense canopy. It is rare or absent in patches <10 km2, and may only use them if they are within ranging distance of larger fragments (Sitompul et al. 2004). It has also been recorded up to at least 950 m, at forest edges and in isolated trees or groves in parkland far from closed forest, although its occurrence in parkland may be very infrequent. Nest-cavities tend to be situated within evergreen forest in the trunks of large deciduous trees, especially Tetrameles nudiflora, a species that is important for other threatened species on the island (e.g. Sulphur-crested Cockatoo Cacatua sulphurea) (BirdLife International 2001).
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 19
Movement patterns: Not a Migrant
Threats [top]
Major Threat(s): Habitat destruction and fragmentation stemming from small-scale logging, fuelwood collection and clearance for cultivation or pasture poses the main threat. These pressures are exacerbated by fire resulting from a dry climate and uncontrolled burning to encourage new growth for cattle. Since the 19th century, c. 60% of forest has been lost. This hornbills preference for lowland areas further compounds the threat of habitat loss, as do the reported minor impacts of trade and exploitation for food (BirdLife International 2001). Although one large area of lowland forest appears to be well protected in the Manupeu-Tanadaru National Park (D. Mulyawati in litt. 2010), forest loss is likely to be continuing outside of reserves (T. OBrien in litt. 2010).
Conservation Actions [top]
Conservation Actions: Conservation Actions Underway
CITES Appendix II. Populations occur in the recently established Manupeu-Tanahdaru National Park (MTNP) and Laiwangi-Wanggameti National Park (LWNP) (1,350 km2 combined), which are now monitored by government-run management authorities set up in 2006. Burung Indonesia has been working intensively since 2002/2003 on strengthening Sumbas national park management. The project included facilitating local communities and government to develop village conservation agreement and to agree on the demarcation of the MTNP, resulting a reduced external pressure on illegal logging, forest destruction, and better law enforcement (A. Dian in litt. 2009). Population surveys were carried out for the species in the MTNP in 2009 (D. Mulyawati in litt. 2010). The illegal wildlife trade has been monitored since 2004, and in four big cities in Sumba there have been no cases of the species being recorded in trade/captivity (D. Mulyawati in litt. 2010, M. Kinnaird in litt. 2016).
Conservation Actions Proposed
Conduct detailed research into the breeding and foraging ecology of the species. Conduct an accurate population survey across the entire island and implement a monitoring programme to establish population trends. Gazette strict nature reserves at Yawila, Puronumbu and Luku Melolo, a wildlife sanctuary at Lulundilo and a forest park at Tanjung Ngunju. Support initiatives to establish and manage further protected areas. Continue to work with local communities to prevent lowland forest clearing, hunting and trapping. Reconcile differences in population estimates.
Amended [top]
Amended reason: Edited Conservation Actions Information text. Added a Facilitator/Compiler.
Citation: BirdLife International. 2017. Rhyticeros everetti (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22682535A117067987. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T22682535A117067987.en. Downloaded on 07 September 2018.
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