Archived 2010-2011 topics: Viridian Dacnis (Dacnis viguieri): downlist to Least Concern?

Posted on December 8, 2010 by Andy Symes

Viridian Dacnis Dacnis viguieri occurs in north-west Colombia (north Chocó, north-west Antioquia, south-west Córdoba) and east Panama (east Darién). Within this small range it is generally rare. It is listed as Near Threatened on the IUCN Red List because it was thought to have a restricted range that approaches the threshold for listing as Vulnerable (<20,000 km2) combined with severely fragmented habitat or occurrence at approximately ten or fewer locations and a continuing decline in its habitat, population size or number of locations/sub-populations.

However, this species has been mapped by Natureserve/BirdLife International as having an estimated Extent of Occurrence (EOO) of 56,500 km2, hence it does not appear to approach the IUCN thresholds and appears to warrant downlisting to Least Concern. However, if the species has experienced declines over the past three generations (11 years, BirdLife International unpubl. data) approaching 30% it may warrant listing as Near Threatened under the A criterion (population declines). Given its relatively large range size it seems unlikely that this species will have a population approaching 10,000 mature individuals so it would not qualify as threatened or Near Threatened on population size under the C criterion.

Comments on the population trends of this species and its proposed downlisting are welcomed.

(This discussion was started as part of the 2010 Red List update)

Dacnis viguieri se encuentra al noroeste de Colombia (norte del Chocó, noroeste de Antioquia, suroeste de Córdoba) y este de Panamá (este de Darién); siendo una especie rara a lo largo de su área de distribución. La extensión de la presencia (EOO) calculada para la especie es de 56.500 km2.

Related posts:

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2 Responses to Archived 2010-2011 topics: Viridian Dacnis (Dacnis viguieri): downlist to Least Concern?

  1. George R. Angehr says:
    January 23, 2011 at 6:13 pm

    The range map for this species for Panama as shown by NatureServe is far too extensive, by perhaps 10 fold. To the best of my knowledge, the species has only been recorded from around El Real, Cana, and Jaque. The map includes areas such as Cerro Sapo, Garachine, and Punta Patino where the species has never been recorded, despite surveys.

    Similarly, the range map for Colombia shown by NatureServe is much more extensive than that shown by Hilty and Brown in A Guide to the Birds of Colombia. It appears to me that the range is perhaps three times larger on NatureServe. It is unclear whether this is based on new data, or whether the map is simply imprecise. Any proposal for downlisting should be based on primary data about the distribution of the species, not generalized maps such as NatureServe. In my opinion, the grounds proposed for downlisting are insufficient in the absence of primary data, and the status quo should be maintained.

    The small known range of the species in Panama is undergoing continued deforestation near El Real, and probably in the Jaque Valley as well. Deforestation is also taking place within the Colombian part of its range as well. An assessment of this deforestation should be also be part of a proposal for revision in status.

  2. Andy Symes says:
    January 31, 2011 at 3:28 pm

    Fundacion ProAves have provided the following information from the species’s Colombian range:

    The revised EOO of 56,500 km2 seems widely optimistic for a species known to have a highly restricted range, very poorly known and considered rare from all accounts. The report that it occurs on both slopes of Serranía de Baudó (“Large numbers were formerly collected on both slopes of the north Serranía de Baudó, north-west Chocó, suggesting that it was once locally common” BirdLife International (2011) Species factsheet: Dacnis viguieri) is misleading. The species is known from 44 specimens in Colombia (www.biomap.net), all but four are from a single location – Jurado, Chocó on the Pacific coast at the base of Serranía de los Saltos collected by Von Sneidern in 1940. Of the other four specimens, one site is unknown, one from Turbo (1959) – now deforested, and two from Alto de Quimari (just east of Turbo – fragmented) and an observation locality (inc. Hilty and Brown 1986). A recent record from Panama comes from Cana, at the foothills of Pirre so it probably also occurs on the Colombian side of Cerro Tacarcuna.

    There appears no new information on the species’ range or population to justify the increase in EOO. Of the known range (estimated at far below 20,000 km2 EOO), when one compares the species’ extent of habitat within that range, there has been a drastic decline in the past decade in suitable habitat in the Urabá lowlands and the Sinú valley as a result of banana plantations, pasturelands and now African palm oil. This agricultural expansion has cleared the lowlands almost entirely and is encroaching on the foothills of the Western Andes and Serranía de Darien (majority of the species range). While the area of Jurado is under lower pressure, we consider the species still qualifies for Vulnerable meeting criteria B1b(i,iii).

    Fundacion ProAves (in press) The status of various threatened or potentially threatened birds in Colombia. Conservación Colombiana 14

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