Archived 2014 discussion: Versicoloured Barbet (Eubucco versicolor) is being split: list E. steerii as Vulnerable or Near Threatened, E. glaucogularis as Near Threatened and E. versicolor as Least Concern?

The initial deadline for comments on this topic is 28 April 2014, and therefore later than for most other topics currently under discussion.

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines

Lynx Edicions and BirdLife International will soon publish the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.

The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.

Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.

The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), to be incorporated into subsequent Red List updates.

Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.

Versicoloured Barbet Eubucco versicolor is being split into E. versicolor, E. steerii and E. glaucogularis, following the application of criteria set out by Tobias et al. (2010).

Prior to the taxonomic change, E. versicolor (BirdLife species factsheet) was listed as Near Threatened under criterion A3c, on the basis that is was suspected to undergo a moderately rapid population decline, approaching 30% over 26 years (estimate of three generations), based on a model of future deforestation in the Amazon basin. According to the analysis, this species was projected to lose 24.2-26.8% of suitable habitat within its distribution over 26 years.

The pre-split species was characterised as preferring submontane humid forest at 1,000-2,000 m; also occurring in old secondary forest and rarely in the dry forests of Bolivia (del Hoyo et al. 2002).

The primary threat to the pre-split species was judged to be accelerating deforestation in the Amazon basin through the clearance of land for cattle ranching and soy production, facilitated by expansion of the road network (Soares-Filho et al. 2006, Bird et al. 2011).

E. steerii occurs in northern Peru, from central Amazonas and south-western Loreto, south through San Martin and La Libertad, to northern Huanuco (Short and Horne 2001).

A model of forest loss in the Amazon basin after 2002 (Soares-Filho et al. 2006) suggests that this species will lose c.28% of suitable habitat in the Amazonian portion of its range (as defined in the model, and accounting for 78% of this species’s global extent of suitable habitat) over a period of 26 years. The species is thought to show high forest dependence, but it is unclear whether it is susceptible to fragmentation, edge-effects or persecution, thus additional declines have not been factored in for these reasons.

Based on this analysis and methods used by Bird et al. (2011), this species would be suspected to decline by 21.5% over 26 years from 2002, suggesting that it qualifies as Least Concern, as it does not approach the threshold for Vulnerable under criterion A4c of a 30% decline over three generations. However, it is proposed here that the methods used by Bird et al. (2011) are not adequate for predicting habitat loss for this species, and that given the extent of agricultural and urban development in and adjacent to its range, the species could be suspected to be undergoing a rapid population decline approaching or exceeding of 30% over 26 years, and thus may qualify as Near Threatened or Vulnerable under criteria A2c+3c+4c.

E. glaucogularis occurs in central Peru, from Huanuco south to northern Cuzco (Short and Horne 2001).

A model of forest loss in the Amazon basin after 2002 (Soares-Filho et al. 2006) suggests that this species will lose c.30-31% of suitable habitat in the Amazonian portion of its range (as defined in the model, and accounting for c.54% of this species’s global extent of suitable habitat) over a period of 26 years. The species is thought to show high forest dependence, but it is unclear whether it is susceptible to fragmentation, edge-effects or persecution, thus additional declines have not been factored in for these reasons.

Based on this analysis and methods used by Bird et al. (2011), this species would be suspected to decline by 16.2% over 26 years from 2002, suggesting that it qualifies as Least Concern, as it does not approach the threshold for Vulnerable under criterion A4c of a 30% decline over three generations.

However, it is proposed here that the methods used by Bird et al. (2011) are not adequate for predicting habitat loss in this species’s range and that this analysis underestimates its threat status. It is suggested, therefore, that this species may qualify as Near Threatened under criteria A2c+3c+4c; C2a(ii), on the basis that it could be undergoing a moderately rapid decline, approaching 30% over 26 years, and that the population may be moderately small, approaching as few as 10,000 mature individuals, assumed to form a single sub-population and inferred to be in on-going decline owing to habitat loss.

E. versicolor (as defined following the taxonomic change) occurs from Cuzco and Puno in southern Peru, south to Cochabamba in northern Bolivia (Short and Horne 2001).

A model of forest loss in Amazonia after 2002 (Soares-Filho et al. 2006) suggests that this species will lose c.15-18% of suitable habitat in the Amazonian portion of its range (as defined in the model, and accounting for c.93% of this species’s global extent of suitable habitat) over a period of over 26 years. The species is thought to show high forest dependence, but it is unclear whether it is susceptible to fragmentation, edge-effects or persecution, thus additional declines have not been factored in for these reasons.

Based on this analysis and methods used by Bird et al. (2011), this species would be suspected to decline by 16.4% over 26 years from 2002, suggesting that it qualifies as Least Concern, as it does not approach the threshold for Vulnerable under criterion A4c of a 30% decline over three generations. It is suggested here that this analysis provides an appropriate indication of the species’s status and that it qualifies as Least Concern.

Comments are invited and further information would be welcomed.

References:

Bird, J. P., Buchanan, G. M., Lees, A. C., Clay, R. P., Develey. P. F., Yépez, I. and Butchart, S. H. M. (2011) Integrating spatially explicit habitat projections into extinction risk assessments: a reassessment of Amazonian avifauna incorporating projected deforestation. Diversity and Distributions DOI: 10.1111/j.1472 4642.2011.00843.x. http://wileyonlinelibrary.com/journal/ddi.

del Hoyo, J., Elliott, A. and Sargatal, J. (2002) Handbook of the Birds of the World, vol. 7: Jacamars to Woodpeckers. Barcelona, Spain: Lynx Edicions.

Short, L. and Horne, J. (2001) Toucans, Barbets and Honeyguides: Ramphastidae, Capitonidae and Indicatoridae. Oxford, UK: Oxford University Press.

Soares-Filho, B. S., Nepstad, D. C., Curran, L. M., Cerqueira, G. C., Garcia, R. A., Ramos, C. A., Voll, E., McDonald, A., Lefebvre, P. and Schlesinger, P. (2006) Modelling conservation in the Amazon basin. Nature 440: 520–523.

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis 152: 724–746.

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2 Responses to Archived 2014 discussion: Versicoloured Barbet (Eubucco versicolor) is being split: list E. steerii as Vulnerable or Near Threatened, E. glaucogularis as Near Threatened and E. versicolor as Least Concern?

  1. Andy Symes says:

    Preliminary proposals

    Based on available information, our preliminary proposals for the 2014 Red List would be to treat:

    E. versicolor as Least Concern

    E. steerii as Near Threatened, approaching the thresholds for classification as Vulnerable under criterion A2c+3c+4c

    E. glaucogularis as Near Threatened, approaching the thresholds for classification as Vulnerable under criterion A2c+3c+4c; C2a(ii).

    There is now a period for further comments until the final deadline of 14 May, after which recommended categorisations will be put forward to IUCN.

    The final Red List categories will be published on the BirdLife and IUCN websites in mid-2014, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  2. Andy Symes says:

    Recommended categorisations to be put forward to IUCN

    Following further review, there have been no changes to our preliminary proposals for the 2014 Red List status of these species.

    The final categorisations will be published in mid-2014, following further checking of information relevant to the assessments by BirdLife and IUCN.

Comments are closed.