Data Zone
Justification of Red List category
Tree cover loss through conversion of forest to agriculture (particularly for oil palm plantations) is estimated at 19–23% over the past three generations, and with further impacts from degradation the species is suspected to be undergoing a moderately rapid population reduction. The majority of the loss has taken place within the lowlands, within the preferred elevational range of the species. Overall, the population is suspected to have undergone a rapid recent reduction approaching 30% over three generations, hence is assessed as Near Threatened. This reduction will continue unless there is a significant reduction in both the rate of habitat conversion within the range of the species, or until the majority of the population becomes restricted to more secure protected areas.
Population justification
The global population size has not been quantified but is believed to be large given the range and frequency of records in suitable habitat. It is a forest-dependent species and appears to occur only in primary or lightly logged forest (Peh et al. 2005). Within its range, the rate of forest conversion to plantations, primarily oil palm, has been rapid over the past few decades (per Global Forest Watch 2022). There are recent records from remaining forested areas across the range, however the extent of suitable habitat is now considerably smaller than three generations ago. Where habitat is secure the species continues to be regularly observed (eBird 2022), though observing the species away from protected areas is becoming increasingly difficult. In Thailand, all recent records are from the vicinity of Hala Bala Wildlife Sanctuary and Bang Lang National Park (eBird 2022) although there are historic records from further north (Treesucon and Limparungpatthanakij 2018)—the population there now must be very small. In Peninsular Malaysia, there are post-2000 records from throughout (MNS Bird Conservation Council 2021) but mostly from protected areas or forest concessions, and the population is thought to be declining rapidly in lowland Indonesia, although here (especially in Kalimantan), there are large tracts of suitable habitat remaining. Forest loss is much lower in Brunei, where impacts on the species may be much less severe and much of the forest here is likely to be suitable for this species. Overall, the population is considered highly unlikely to meet or approach the population size threshold for listing as threatened (<10,000 mature individuals) although this requires confirmation.
Trend justification
This species favours good-quality forest (Peh et al. 2005, Eaton et al. 2021, eBird 2022), only occasionally occurring in heavily degraded habitats. Consequently the population impact of forest cover loss is expected to be broadly equal. In the three generations to 2021 (13.5 years; Bird et al. 2020), forest cover in this species' range was reduced by 19–23%, depending on the forest cover thresholds set (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). This value does not account for the impact of forest degradation, hence the population rate of reduction from habitat loss is likely to be greater than this. Similarly, since the species is most regularly encountered in low-lying forest (eBird 2022), where losses are greater, the overall rate of population reduction is suspected to be equivalent to c.15–29% over the last ten years. This rate is also precautionarily projected over the next three generations, although beyond that rates of loss may slow as the percentage area of forest outside protected areas diminishes.
Harpactes kasumba is confined to the Sundaic lowlands, where it is known from southernmost peninsular Thailand, Sabah, Sarawak and Peninsular Malaysia, Singapore (formerly), Kalimantan and Sumatra, Indonesia and Brunei (BirdLife International 2001).
This species occurs mainly in primary or lightly logged lowland evergreen forests (Peh et al. 2005). It is commonest below 600 m, but occurs occasionally up to 1,200 m in montane dipterocarp forest on Borneo. It is also recorded in peatswamp forest, as well as logged areas and, occasionally, cocoa plantations.
Forest destruction in the Sundaic lowlands of Indonesia and Malaysia has been extensive, for timber and conversion to agriculture. In particular the rapid expansion of oil palm has driven the conversion of the majority of remaining lowland forest in the region. Between 2007 and 2021, tree cover was reduced in its range by 19–23% (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). Most of this loss has occurred within the lowlands, where the highest densities of the species would be expected. Moreover, the impact of forest degradation will have added to rates of decline. Associated with the forest loss has been an increase in fire frequency, extent and severity, particularly during strong El Nino events (as in 1998). While the species can use secondary growth and higher elevations, the extent of the threats is such that this species' population is likely to be declining rapidly.
Conservation Actions Underway
No targeted conservation actions are known for this species, although it occurs in a number of protected areas.
Conservation Actions Proposed
Conduct ecological studies to improve understanding of this species' habitat requirements. In particular, studies should aim to determine levels of tolerance of secondary habitats, particularly in areas where primary forests are completely removed. Repeat surveys across the range to estimate population size and trends. Improve the management of protected areas within the species' range. Increase the area of suitable habitat that has protected status. Implement measures to reduce the number and severity of forest fires.
Text account compilers
Berryman, A.
Contributors
Gilroy, J., Benstead, P. & Taylor, J.
Recommended citation
BirdLife International (2024) Species factsheet: Red-naped Trogon Harpactes kasumba. Downloaded from
https://datazone.birdlife.org/species/factsheet/red-naped-trogon-harpactes-kasumba on 22/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/12/2024.