Archived 2016 topics: White-throated Barbtail (Premnoplex tatei) is being split: list P. tatei and P. pariae as Endangered?

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

Lynx Edicions and BirdLife International will soon publish the second volume of 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 2 of the checklist (for passerines) will begin to be incorporated into the 2016 Red List update, with the remainder 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.

White-throated Barbtail Premnoplex tatei is being split into P. tatei and P. pariae, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, Premnoplex tatei was listed as Vulnerable under criterion B1ab(i,ii,iii,v), on the basis that it had a very small range, which was presumed to be declining in line with the conversion of its habitat to plantations, and changing agricultural techniques. It may have qualified as Endangered, but it was found at 7 locations* in the understorey of montane humid forest in the mountains of north-east Venezuela. P. tatei (as now defined following the taxonomic change) is known from four locations (Cerros Peonía, Turimiquire, Macanillal and Negro in north-east Venezuela). Its already very restricted habitat (EOO <2,500 km2) is declining due to habitat loss, and this is suspected to be driving a population decline. The population prior to the taxonomic change was in the range of 2,500-9,999 individuals (BirdLife International 2016). No direct estimate for this newly defined taxon is known, but as the population for the split taxon has been estimated at 3,600 individuals (Bond et al. 1989). Therefore, the population for the newly defined P. tatei may be conservatively kept in the 2,500-9,999 individuals range unless further information is available. Given this species’s highly restricted range, which is declining due to habitat loss it is proposed that it be listed as Endangered under criterion B1ab(i,ii,iii,v).

P. pariae is known from three locations* (Cerros Humo, Olvido and Azul in the Paria Peninsula of north-east Venezuela). It is found in the understorey of montane humid forest, and has suffered from habitat destruction in its restricted range (EOO <475 km2). Its range is within the Paria Peninsula National Park, but there has been a historical lack of legal enforcement in the park, and habitat destruction continues (Remsen and Sharpe 2016). The population has previously been estimated at 3,600 individuals (Bond et al. 1989), roughly equivalent to 2,400 mature individuals. However, given the age of this figure, and the fact that the population is suspected to be declining in line with the loss of its habitat, it may require revising. Given this species’s highly restricted range, which is declining due to habitat loss, it is proposed that is be listed as Endangered under criterion B1ab(i,ii,iii,v).

Comments are invited on these proposed categories and further information would be welcomed.

*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

References:

BirdLife International (2016) Species factsheet: Premnoplex tatei. Downloaded from http://www.birdlife.org on 09/09/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 09/09/2016

Bond, R. E., Convey, P., Sharpe, C. J., Varey, A. (1989) Cambridge Columbus zoological expedition to Venezuela 1988. University of Cambridge , Cambridge, UK

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

IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.

Remsen, J.V., Jr and Sharpe, C.J. (2016). White-throated Barbtail (Premnoplex tatei). 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 http://www.hbw.com/node/56527 on 9 September 2016).

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 2016 topics: White-throated Barbtail (Premnoplex tatei) is being split: list P. tatei and P. pariae as Endangered?

  1. Chris Sharpe says:

    Pariae. We found 2.4 pairs/ha in good habitat on Cerro El Olvido, above Macuro, in 1988, from which we extrapolated to 900 pairs E of Cerro Patao (Bond et al. 1989). Karl Evans and his Oxford Uni team, working on Cerro de Humo six years later, found much lower densities, as did Nacho Areta a decade later still (the latter about half what we found). The forest on Cerro de Humo is likely more disturbed. Taking this into account, a population estimate of 2400 mature individuals is probably not wide of the mark. In the current national Red Data Book, we have continued to consider P. tatei sensu lato Vulnerable.

    Tatei. Without any hard data, I would suppose that the population of this taxon is a little larger than pariae, even though the latter appears to be found at higher densities. Its conservation situation is similar. Remaining forest in the Turimiquire Massif should be protected by the creation of a national park.

    Jorge Pérez-Emán of IZT-UCV would doubtless be able to provide expert comment on this split, and the status of tatei.

  2. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 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 of 28 October, 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 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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