Black-fronted Francolin (Pternistis atrifrons): revise global status?

Black-fronted Francolin (Pternistis atrifrons) was recently split from P. castaneicollis (del Hoyo and Collar 2014) and is currently listed as Least Concern (BirdLife International 2017). P. atrifrons has only been reported from southern Ethiopia, around the town of Mega, and in the extreme north of Kenya. However, a recent, brief survey failed to locate the species where it had been seen in Kenya, and there remains just one sighting in this country from 1975 (Töpfer et al. 2014, del Hoyo et al. 2017). This is despite the presence of suitable habitat for the species (areas of woodland containing low shrubs, interspersed with open patches and taller vegetation [Töpfer et al. 2014]). This habitat is threatened, though, within the species’ range, with most juniper forest in the area cleared and threatened by harvesting for timber, forest fires and grazing (Töpfer et al. 2014).

Following the work by Töpfer et al. (2014), further survey work was carried out and presented in Gedeon et al. (2017). Information from both of these studies was used by Gedeon et al. (2017) to model the potential range and estimate the population size of Black-fronted Francolin. Gedeon et al. (2017) then use this information to make a decision regarding the Red List status of this species. Their assessment, however, does not meet with Red List guidelines for the application of the categories and criteria (see IUCN Standards and Petitions Subcommittee 2017). Despite this, it does appear that the species warrants reassessment, and so the species is assessed here against all of the criteria.

 

Criterion A – Gedeon et al. (2017) suggest that the species should be listed as Endangered under criterion A2c based on a decline in AOO and habitat quality. In addition to the ongoing threats, they also suggest that climate change may severely impact the species in the future. However, they provide no quantitative evidence to back up this rate of decline, and they do not highlight that this past decline has to have occurred within the last 3 generations (IUCN 2001, 2012) (for Black-fronted Francolin this is only c.12 years) so it is not certain whether they took this into account when suggesting there has been a past 50% decline.

Given the apparent current scarcity of this species, as shown by the surveys of Töpfer et al. (2014) and Gedeon et al. (2017), the taxon has most likely declined from when it was considered common (Macworth-Praed and Grant 1952, Urban and Brown 1971); and the ongoing and future threats mean that declines are likely to continue. Therefore, the species can be assessed as undergoing a continuing decline, but we do not have the evidence to say the rate of this decline. Thus we cannot list the species under this criterion.

 

Criterion B – Gedeon et al. (2017) suggest that the species should be listed as Endangered under criteria B1ab(ii,iii,v)+2ab(ii,iii,v). However, neither of their range values meets the guidelines for how to calculate them (see IUCN Standards and Petitions Subcommittee 2017). Firstly, the value they give for the species’ Extent of Occurrence (EOO) (1,286km2) has not been calculated using a Minimum Convex Polygon as required by IUCN (see IUCN 2001, 2012, Joppa et al. 2016), instead being a value for the area of suitable habitat. This is therefore not an EOO. It is instead a rough Maximum Area of Occupancy for the species, and would be better compared to the Area of Occupancy (AOO) threshold values.

Secondly, they give no explanation of how they estimated their AOO value. From their observations it is fair to say that not all of the suitable habitat is occupied. However, to correctly calculate an AOO to IUCN guidelines a 2km x 2km grid system should be employed, and the total area of all occupied grid cells summed to give the AOO (per IUCN Standards and Petitions Subcommittee 2017), rather than the ‘estimated’ methodology of Gedeon et al. Therefore, we cannot immediately use either value of Gedeon et al. as they have done.

We must stress that while the exact values of Gedeon et al. (2017) cannot be used it is still possible that the species does meet the relevant thresholds for Endangered under these criteria. It is just that the data is currently not available to do so. The range map currently held by BirdLife shows a larger distribution than the studies of Töpfer et al. (2014) and Gedeon et al. (2017) have shown. As such the BirdLife map is currently in revision, and this revision will give clearer estimates of range size parameters. Based on the data of Gedeon et al. (2017) though, we can get a rough approximation that the species may warrant uplisting to Vulnerable under criterion B2ab(ii,iii,v). This is because the potential Maximum AOO falls below the threshold for Vulnerable under criterion B2 (2,000km2); there is evidence from which declines in the EOO, AOO, habitat area/quality and population can be at least inferred; and Gedeon et al. suggest that the population may be considered to be severely fragmented*.

 

Criterion C – Gedeon et al. (2017) estimated the population size to be 1,100-2,100 mature individuals. While this is derived from the AOO value they estimated (see above) this is the best possible estimate that is available; though given the uncertainty over the AOO value it may be most appropriate to place the population size in the range 1,000-2,499 mature individuals instead.

The species is considered to be undergoing a continuing decline but the overall rate of decline is not known and so the species cannot be listed under criterion C1. Also the species is not known to undergo extreme fluctuations and Gedeon et al. (2017) suggest that the species may be split into four separate sub-populations. Therefore, it does not warrant listing under criteria C2b and C2a(ii) respectively. However, given that the species is potentially split into multiple sub-populations, it is likely that the largest sub-population is <1,000 mature individuals (especially given the lower end of the potential population size estimate), though there is insufficient evidence to say with any confidence that the largest sub-population is ≤250 mature individuals; and if this was the case the overall population size estimate would likely require revision. Therefore, the species likely qualifies as Vulnerable under criterion C2a(i).

 

Criterion D – The minimum population size estimate approaches the threshold for Vulnerable under criterion D1, and hence the species would warrant listing as Near Threatened under this criterion. Uncertainty over the number of ‘locations’ (see IUCN Standards and Petitions Subcommittee 2017) where the species occurs and its AOO means it cannot be assessed against criterion D2 (although the AOO is still likely greater than the threshold value of 20km2 typically required for listing under this criterion).

 

Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.

 

Therefore, the species at least warrants uplisting to Vulnerable under criteria B2ab(ii,iii,v); C2a(i) pending further comments and further information regarding range size parameters. 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 about the proposed listing.

 

*Severely fragmented has a specific definition given in IUCN Standards and Petitions Subcommittee (2017). It is not stated whether Gedeon et al. followed this specific definition, but precautionarily the decision of Gedeon et al. is followed here. The area of impact of individual threats is uncertain and so the number of ‘locations’ (see IUCN Standards and Petitions Subcommittee 2017) where the species is found is unknown.

 

References

BirdLife International. 2017. Species factsheet: Pternistis atrifrons. Downloaded from http://www.birdlife.org on 16/11/2017.

del Hoyo, J.; Collar, N. J. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

del Hoyo, J.; Collar, N.; Christie, D. A.; Kirwan, G. M. 2017. Black-fronted Francolin (Pternistis atrifrons). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/467102 on 16 November 2017).

Gedeon, K.; Rödder, D.; Zewdie, C.; Töpfer, T. 2017. Evaluating the conservation status of the Black-fronted Francolin Pternistis atrifrons. Bird Conservation International online access, doi: 10.1017/S0959270917000363.

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. Available at: www.iucnredlist.org/technical-documents/categories-and-criteria.

IUCN Standards and Petitions Subcommittee. 2017. Guidelines for Using the IUCN Red List Categories and Criteria. Version 13. Prepared by the Standards and Petitions Subcommittee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Joppa, L. N.; Butchart, S. H. M.; Hoffmann, M.; Bachman, S. P.; Akçakaya, H. R.; Moat, J. F.; Böhm, M.; Holland, R. A.; Newton, A.; Polidoro, B.; Hughes, A. 2016. Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation Biology 30: 362-370.

Mackworth-Prae, C. W.; Grant, C. H. B. 1952. African Handbook of Birds Series 1 Volume 1. Birds of Eastern and North Eastern Africa. Longmans, Green and Co., London, New York and Toronto.

Töpfer, T.; Podsiadlowski, L.; Gedeon, K. 2014. Rediscovery of the Black-fronted Francolin Pternistis (castaneicollis) atrifrons (Conover, 1930) (Aves: Galliformes: Phasianidae) with notes on biology, taxonomy and conservation. Vertebrate Zoology 64(2): 261-271.

Urban, E. K.; Brown, L. H. 1971. A Checklist of the Birds of Ethiopia. Haile Sellassie I University Press, Addis Ababa, Ethiopia.

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4 Responses to Black-fronted Francolin (Pternistis atrifrons): revise global status?

  1. Kai Gedeon says:

    Dear James, we have read your forum entry and have some suggestions regarding the evaluation of Pternistis atrifrons. For this purpose we would like to send you updated maps of EOO and AOO. Could we contact you by email? Best regards, Kai Gedeon

  2. James Westrip (BirdLife) says:

    Following some discussion, Kai Gedeon, Till Töpfer and Heiner Nagel have re-examined the information from recent surveys for the species and have calculated an AOO for the species of 456km2. Looking at the other subcriteria and conditions for listing under criterion B2 it was decided;
    (a)
    “We identified three locations (A, B and C in the map), following the Red List Guideline, Version 13, March 2017 (page 58).
    Location A: An isolated ridge in the north with a small area of suitable habitats. Most serious plausible threat is habitat destruction by forest fire. These are common in the area and a single event could lead to extinction.
    Location B: Occurrences around Mega town, with a rapidly growing human population, both in the town itself and in the surrounding area. Most serious plausible threat is direct human persecution. In our field studies and interviews were found that hunting with snares is widespread, especially in the near vicinity of the settlements.Therefore the area around Mega is under heavy pressure, unlike the remote places in the west and south.
    Location C: Ridge along the north-south escarpment. Most serious plausible threat is habitat lost and disturbance by increasing human activities (timber harvesting, firewood collection, grazing).” K. Gedeon in litt. (2018).
    And after discussion, given the best available information, and the potential impacts of major threats to the species it was considered that the species may be undergoing a continuing decline in (i) extant of occurrence, (ii) area of occupancy, (iii) extant and quality of habitat, and (v) number of mature individuals. This would meet the threshold and conditions for listing as Endangered under criterion B2ab(i,ii,iii,v).
    The map for the species is also under review by BirdLife, and so a new EOO value is pending the running of the appropriate models to calculate the area of the Minimum Convex Polygon. This could then mean that the species warrants listing as Endangered under criterion B1ab(i,ii,iii,v) too, but at the moment this is not certain.

  3. James Westrip (BirdLife) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2018 Red List would be to list this species as Endangered under criterion B2ab(i,ii,iii,v).

    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 the initial proposal.
    The final 2018 Red List categories will be published on the BirdLife and IUCN websites in November, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  4. James Westrip (BirdLife) says:

    Recommended categorisation to be put forward to IUCN

    Following further review, the recommended criteria string for this species has been changed. The species is still proposed to be listed as Endangered, but under criteria B1ab(i,ii,iii,v)+2ab(i,ii,iii,v).

    Final 2018 Red List categories will be published on the BirdLife and IUCN websites in November, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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