Archived 2016 topics: The newly described taxon Thyrophilus sernai is to be recognised as a species by BirdLife: list 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.

The newly described taxon Thyrophilus sernai is to be recognised as a species by BirdLife following application of the Tobias et al. (2010) criteria, which support its distinctiveness from congeners.

T. sernai, Antioquia Wren, is known from six localities in the Department of Antioquia, Colombia, on the banks of the Cauca River Canyon (Lara et al. 2012). It is probably only found in semi-decidous dry forest habitat with an open understorey (Lara et al. 2012, Fjeldså 2016). Its Extent of Occurrence is predicted to be small as it is only found along a c.150km stretch of the river (Lara et al. 2012), with early estimates of the area where it is found of c.1,700km2. The species is suspected to be declining as a result of historical and continuing habitat alteration (Lara et al. 2012), as land has been converted for mining, agriculture, pasture and urban areas (Lara et al. 2012). Additionally, a large amount of its range may be lost to flooding due to construction of the Pescadero-Ituango hydro-electric dam (Lara et al. 2012) due for completion in 2018; the effect of which would at least mean that the species is found at <5 locations*. The reservoir is predicted to be 79 km in length (Hidroeléctra Ituango webpage), which would represent c.53% of its habitat being affected by just the reservoir. Therefore, the species likely qualifies as Endangered under criteria A3c+4c; B1ab(i,ii,iii,iv,v).

*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:

Fjeldså, J. 2016. Antioquia Wren (Thryothorus sernai). 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/204359 on 29 September 2016).

Lara, C.E., Cuervo, A.M., Valderrama, S.V., Calderón-F., D. and Cadena, C.D. 2012. A new species of wren (Troglodytidae: Thryophilus) from the dry Cauca River Canyon, northwestern Colombia. Auk 129(3): 537–550.

Hidroeléctra Ituango webpage: http://www.hidroituango.com.co

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.

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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3 Responses to Archived 2016 topics: The newly described taxon Thyrophilus sernai is to be recognised as a species by BirdLife: list as Endangered?

  1. Thomas Donegan says:

    I would support EN here for the reasons stated.

  2. Although there is no data about their population size or density, the Antioquia Wren has been listed as rare and difficult to find throughout its range (Cauca River) propose that their population might be low due to dry forest reduction in Cauca River, which could also reduce the availability of breeding areas.

    It is difficult to make an overall population estimation based on the availability of habitat for breeding, because of the absence of this species in many areas where conditions seem to be suitable. Habitat loss and deforestation are limiting factors for the presence of this wren in many areas of its range, particularly on sites disturbed by construction the new roads or agriculture.

    he species likely qualifies as Endangered under criteria A3c+4c; B1ab(i,ii,iii,iv,v).

  3. 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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