Southern Crowned-pigeon (Goura scheepmakeri) is being split: list both G. scheepmakeri and G. sclaterii as Vulnerable?

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.

Southern Crowned-pigeon Goura scheepmakeri is being split into G. scheepmakeri and G. sclaterii, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, G. scheepmakeri (BirdLife species factsheet) was listed as Vulnerable because its population was suspected to be undergoing a rapid decline (30-49% over 20 years [estimate of three generations]), owing to on-going hunting pressure and the loss and degradation of lowland forest, although few data are available on the species and its tolerance of logged forest is poorly known.

G. sclaterii occurs in the south-western lowlands of Papua New Guinea, mostly west of the Fly River, ranging west into the south-eastern lowlands of West Papua, Indonesia, to the Mimika River (del Hoyo et al. 1997, Gibbs et al. 2001).

G. scheepmakeri (as defined following the taxonomic change) is thought to occur throughout much of the southern lowlands of Papua New Guinea east of the Fly River, only being known to be extant in the east of its potential distribution (Hall Sound and Mt Epa east to Orangerie Bay), having been apparently extirpated from the vicinity of Port Moresby and much of the south-eastern and southern Trans-Fly region (del Hoyo et al. 1997, Gibbs et al. 2001).

Both species inhabit closed-canopy forest, drier and more open forest, and gallery forest, including seasonally flooded areas, ranging up to at least 500 m (del Hoyo et al. 1997, Gibbs et al. 2001).

Both of these species are thought to be subjected to high hunting pressure and substantially impacted by forest destruction and degradation. Shearman et al. (2009) estimate, through remote sensing analyses, that Papua New Guinea experienced net forest loss of c.15% between 1972 and 2002, primarily due to logging, with a further 8.8% degraded over the same period. Within the potential range of G. scheepmakeri, rates of forest loss and degradation over the same period varied according to province, with the Gulf, Western and Central Provinces seeing forest loss of 6.15%, 11.92% and 17.59% respectively, and rates of degradation being 13.37%, 10.65% and 7.56% respectively (Shearman et al. 2009).

It is suggested that both G. sclaterii and G. scheepmakeri be listed as Vulnerable under criteria A2bcd+3bcd+4bcd; C2a(ii), because their populations are estimated to be small, each probably including fewer than 10,000 mature individuals and forming single subpopulations, and are inferred to be in continuing decline, which in both cases is suspected to be rapid (30-49% over 20 years), based on local extirpations and known threats.

Comments on these suggested categories and further information would be welcomed.

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (1997) Handbook of the birds of the world, Vol 4: Sandgrouse to Cuckoos. Barcelona, Spain: Lynx Edicions.

Gibbs, D., Barnes, E. and Cox, J. (2001) Pigeons and doves: a guide to the pigeons and doves of the world. Robertsbridge, UK: Pica Press.

Shearman, P. L., Ash, J., Mackey, B., Bryan, J. E. and Lokes, B. (2009) Forest Conversion and Degradation in Papua New Guinea 1972-2002. Biotropica 41: 379–390.

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.

Related posts:

  1. Archived 2012-2013 topics: Victoria Crowned-pigeon (Goura victoria): downlist to Near Threatened?
  2. Pheasant Pigeon (Otidiphaps nobilis) is being split: list O. insularis as Endangered and O. aruensis as Vulnerable?
  3. New Zealand Pigeon (Hemiphaga novaeseelandiae) is being split: list H. chathamensis as Vulnerable and H. novaeseelandiae as Near Threatened?
  4. Pompadour Green-pigeon (Treron pompadora) is being split: list T. aromatica as Vulnerable and four other newly defined species as Near Threatened?
  5. Whistling Green-pigeon (Treron formosae) is being split: list T. formosae as Near Threatened?
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3 Responses to Southern Crowned-pigeon (Goura scheepmakeri) is being split: list both G. scheepmakeri and G. sclaterii as Vulnerable?

  1. Guy Dutson says:

    Although there is no monitoring of crowned pigeons, numbers do not appear to have declined at the main birding site around Ekame lodge on the Fly River, and I think that the threat from over-hunting has been over-stated. Crowned pigeons also appear to tolerate logging in many locations. as such, declines of 30-49% over 20 years seem unlikely.
    Population size and subpopulation structure and also difficult to assess: <10,000 individuals in a single subpop is plausible.

  2. Joe Taylor says:

    Preliminary proposals

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

    G. scheepmakeri as Vulnerable under criterion C2a(i)

    G. sclaterii as Near Threatened under criterion C2a(ii)

    There is now a period for further comments until the final deadline of 31 March, 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.

  3. 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 later in 2014, following further checking of information relevant to the assessments by BirdLife and IUCN.

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