Kabobo Apalis (Apalis kaboboensis): Revise global status?

BirdLife International factsheet for Kabobo Apalis.

The Kabobo Apalis is endemic to the Democratic Republic of Congo (DRC), and inhabits the montane canopy in the Albertine Rift (Ryan, 2016). The population has recently been estimated to be 4,130 individuals (Dewhurst, 2019), equating to 2,767 mature individuals. This species is threatened by habitat loss and degradation to the Albertine Rift, caused by agricultural and subsistence pressures from increasing human populations (Ryan, 2017; Dewhurst, 2019).

The Kabobo Apalis has previously been considered to be Near Threatened, approaching threatened status under criterionB1ab(iii). However, in light of new information, this species may warrant a change in Red List category. It has therefore been reassessed here against all the criteria.

Criterion A: The population trend for this species has not been directly estimated. The main threat known to this species is habitat loss due to agriculture. Between 2000-2018, 7.7% of forest cover in the species’s range was lost (Global Forest Watch, 2020). This translates to a 4.3% reduction over 10 years. The rate of decline is measured over the longer of 10 years or 3 generation lengths of the species (IUCN Standards and Petitions Committee, 2019). The generation length for the Kabobo Apalis has been recalculated to 2.4 years (Bird et al, 2020)*. Rates of decline for this species are therefore calculated over 10 years. Assuming that the population declines at the same rate as habitat loss, then a 4.3% decline is not approaching the threatened threshold (≥30% 3-generation decline) for this criterion. Kabobo Apalis may therefore be considered Least Concern under criterion A.

Criterion B: The Extent of Occurrence for this species has been calculated as 1,800 km² (BirdLife International, 2020). This meets the initial threshold for classification as Endangered under criterion B1 (EOO < 5,000 km²). However, in order to fully qualify as threatened under this criterion, other sub-criteria must be met.

This species is not known to experience any extreme fluctuations, but it is likely to experience a continuing decline in habitat quality due to land-use change. The estimated mean annual rate of deforestation in the Albertine Rift in the DRC is 2% (Ryan et al., 2017). Assuming the rate of loss remained the same, 6% of forest would be lost every 3 years; theoretically, it would therefore take roughly 16 three-year periods for 100% of the forest to be lost. Therefore, the number of locations (whereby location is defined by the IUCN Standards and Petitions Committee [2019] as a geographically distinct area in which a single threat can rapidly eliminate or severely reduce a population within the longer of a single generation or 3 years), is estimated to be 16. This is above the threshold for classification as Vulnerable (≤10 locations), however given its proximity to the threshold, Kabobo Apalis may be considered Near Threatened, approaching the threshold for listing as threatenedunder criterion B1ab(iii).

Criterion C: The global population has been estimated to be approximately 4,130 total individuals (Dewhurst, 2019), equating to 2,767 mature individuals. This reaches the threshold (<10,000 mature individuals) for classification as Vulnerable. However, in order to fully qualify as threatened under this criterion, other sub-criteria must be met. A continuing decline for this species can be inferred from the steady habitat degradation resulting from land-use change occurring in the Albertine Rift, driven by human population increase (Ryan et al., 2017). The Kabobo Apalis is not known to experience any extreme fluctuations, but it is believed to have just one subpopulation. This suggests that all mature individuals may exist in the same subpopulation. Kabobo Apalis may therefore be considered Vulnerable under criterion C2a(ii).

Criterion D: The number of mature individuals for this species is estimated to be 2,767, which is too high to trigger the threatened threshold (<1,000 mature individuals) under this criterion. Kabobo Apalis may therefore be considered Least Concern under criterion D.

Criterion E: To the best of our knowledge, no quantitative analysis has been carried out on this species, so Kabobo Apalis cannot be assessed against this criterion.

We therefore suggest that Kabobo Apalis (Apalis kaboboensis) be listed as Vulnerable undercriterion C2a(ii). We welcome any comments to the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’ Red List status. Therefore, please make sure your comments are relevant to the species’ Red List status and the information requested. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Bird, J.P., Martin, R., Akçakaya, H.R., Gilroy, J., Burfield, I.J., Garnett, S., Symes, A., Taylor, J., Şekercioğlu, Ç.H. and Butchart, S.H.M. (2020), Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology. Online first view.

BirdLife International (2020) Species factsheet: Apalis kaboboensis. Downloaded from http://www.BirdLife.org on 05/05/2020.

Dewhurst, O., 2019, Towards population estimates for birds of Central Africa’s Albertine Rift, MSc thesis, School of Biological Science, Durham University.

IUCN Standards and Petitions Committee, 2019. Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Ryan, P. 2016. Kabobo Apalis (Apalis kaboboensis). In: del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D. A.; de Juana, E. (ed.), Handbook of the Birds of the World Alive, Lynx Edicions, Barcelona, Spain.

Ryan, S., Palace, M., Hartter, J., Diem, J., Chapman, C. and Southworth, J. (2017). Population pressure and global markets drive a decade of forest cover change in Africa’s Albertine Rift. Applied Geography, 81, pp.52-59.

This entry was posted in Africa and tagged , . Bookmark the permalink.

3 Responses to Kabobo Apalis (Apalis kaboboensis): Revise global status?

  1. Red List Team (BirdLife International) says:

    Global Forest Change data on tree cover loss up to 2019 have now been released and made available via Global Forest Watch. Based on these data, over ten years approximately 7% of tree cover with 75% canopy cover was lost from within the species’s range (Global Forest Watch 2020). This does not affect the above assessment under Criterion A.

  2. Red List Team (BirdLife International) says:

    The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you,
    BirdLife Red List Team

  3. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information, our preliminary proposal for the 2020 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from those in the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN. The final publication date will be publicised by IUCN here: https://www.iucnredlist.org/assessment/updates

Leave a Reply

You have to agree to the comment policy.

All comments must follow the rules of usage.

This site uses Akismet to reduce spam. Learn how your comment data is processed.