Justification of Red List Category
Although this species may have a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). Therefore, this species is now listed as Least Concern.
The global population size has not been quantified, but the species is reported to be generally common on Halmahera and Bacan (Frith and Beehler 1998). A survey of the two National Parks Aketajawe-Lolobata estimated a population of 24,128 - 61,553 individuals within the 1,673 km2 protected area (Bashari 2012).
The population is suspected to be in decline owing to on-going habitat loss (Frith and Beehler 1998). A remote sensing study tracked forest loss in the Northern Maluku Endemic Bird Area between 1990 and 2003, and projected rates of deforestation over the next three generations for restricted range bird species found in this region (Vetter 2009). This study estimated the rate of forest loss within the species's geographic and elevation range to be c.8.4% between 1990 and 2003, and projected the loss of c.16.6% of forest in its range over the next three generations (estimated at 23.7 years) (Vetter 2009).
Semioptera wallacii is found on Halmahera, Kasiruta and Bacan, Indonesia (del Hoyo et al. 2009). On Halmahera it is relatively common in primary, logged primary and secondary forest, with an estimate of 24,128 - 61,553 individuals from Aketajawe-Lolobata National Park (Bashari 2012).
This species inhabits primary, secondary and logged rainforest in the lowlands and hills, from sea-level to 1,000-1,200 m (del Hoyo et al. 2009, Burung Indonesia in litt. 2014). Although it occurs in secondary forest, lek sites have only been found in primary forest (Burung Indonesia in litt. 2014). Lek sites are associated with large trees, such as Pometia pinnata, Vatica papuana, Diospyros sp., Canarium sp., Palaquium sp., Alangium javanicum, Helicia moluccana, Diospyros pilosanthera, Myristica sp., and Syzigium sp. (Bashari, 2011).
The primary threat to the species is habitat loss through commercial logging for timber, and clearance for shifting agriculture, mining, settlements and plantations of coconut, clove, nutmeg and timber species (Vetter 2009, Burung Indonesia in litt. 2014, H. Bashari in litt. 2016). Another potential threat is posed by wildfires, which have devastated areas on other Indonesian islands, with the chances of such fires being increased by the conversion of forest to scrub and grassland and the opening up of forests for road construction, as well as selective logging and fragmentation (Vetter 2009). Certain lek sites may be disturbed by unregulated tourism activities.
Conservation Actions Underway
The species occurs in Aketajawe Lolobata National Park (Halmahera) where it is used as a flagship species for promoting the National Park and it is often used in events by the local government as well (Burung Indonesia in litt. 2014, H. Bashari in litt. 2016). The National Park authority has a monitoring program with a focus on lek site rehabilitation (H. Bashari in litt. 2016).
Conservation Actions Proposed
Carry out surveys to assess the species's population size. Conduct regular surveys to monitor the population trend. Track rates of habitat loss through regular studies of satellite images. Increase the area of suitable habitat with protected status.
Text account compilers
Butchart, S., Ekstrom, J., Martin, R, Taylor, J., Symes, A., Westrip, J.
Burung Indonesia, Bashari, B.
BirdLife International (2021) Species factsheet: Semioptera wallacii. Downloaded from http://www.birdlife.org on 27/07/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/07/2021.