The newly described taxon Tatamá Tapaculo (Scytalopus alvarezlopezi) is to be recognized as a species by BirdLife International

Tatamá Tapaculo (Scytalopus alvarezlopezi) was discovered in 1992 on the Pacific slope of the Western Andes of Colombia. Based on the vocalisation and on genetic and morphological analysis of two specimens taken in 1992 and 2015, the species was described in 2017 (Stiles et al. 2017).

Tatamá Tapaculo occurs in the Western Andes, between western Antioquia in the north and Valle del Cauca in the south. It ranges from 1,350 m to 1,800 m on the western slopes, but has locally been found on the eastern slope as high as 2,200 m (Stiles et al. 2017). The species inhabits the dense understory of cloud forests, where it moves around mainly by hopping on the ground and short-distance flights (Stiles et al. 2017). In intact habitat, the species is described as locally very common; however, it does not occur in second-growth forest (Stiles et al. 2017).

While the species’s specific habitat requirements make it vulnerable to habitat degradation and loss, forests within the range remain continuous and not highly threatened (Stiles et al. 2017). However, Tatamá Tapaculo may be susceptible to future climate change, as it may suffer from range contractions and habitat loss (Stiles et al. 2017, see also Velázquez-Tibatá et al. 2013).

Here, we present our assessment against all criteria for this newly described species.

Criterion A – The population trend of Tatamá Tapaculo has not been quantified, and therefore the species cannot be assessed against Criterion A. While its forested habitat remains fairly intact, the species seems to be threatened by range contractions due to climate change. Therefore, we can precautionarily suspect that the species is undergoing a slow decline. 

Criterion B – The Extent of Occurrence (EOO) of this species has been calculated at 23,300 km2. This approaches, but does not meet, the threshold for qualifying as threatened under Criterion B1 (EOO < 20,000 km2). The maximum Area of Occupancy (AOO), as calculated from a 2 km by 2 km grid overlaid over the mapped range, is c. 13,400 km2. This greatly exceeds the threshold for listing as threatened under Criterion B2 (AOO < 2,000 km2). In order to be listed as Near Threatened under Criterion B1, other conditions have to be met.

The subpopulation structure has not been assessed, so it is unclear whether the species meets condition (a). Records on eBird (2019), however, suggest that the species forms at least four relatively large subpopulations and thus cannot be considered severely fragmented sensu IUCN (most individuals are found in small and isolated subpopulations; IUCN 2012). The most serious plausible threat to the species is climate change (Stiles et al. 2017); as the same threat affects the entire population, we can conclude that Tatamá Tapaculo occurs at only one location*, and therefore meets the threshold for listing under condition (a). In the future, climate change may likely lead to a range contraction (see Velázquez-Tibatá et al. 2013), and thus Tatamá Tapaculo is projected to undergo declines in AOO, extent and area of habitat and population size. Thus, the species meets condition b(ii,iii,v). Consequently, Tatamá Tapaculo may be considered Near Threatened, approaching the threshold for listing as threatened under Criterion B1ab(ii,iii,v).

Criterion C – The population size of this species has not been quantified. However, we can derive a preliminary estimate from a congener, the Ecuadorian Tapaculo (Scytalopus robbinsi). This species occurs at a density of c. 2.7 mature individuals per km2 in suitable forest (Hermes et al. 2017). Assuming that the Tatamá Tapaculo occurs at a similar density and that about 20% of the range is occupied, the population may number c. 7,250 mature individuals. Therefore, it is here placed in the band 2,500-9,999 mature individuals. This falls below the threshold for listing as threatened under Criterion C (<10,000 mature individuals). However, in order to be listed under this criterion, further conditions have to be met.

The population is suspected to decline slowly due to a range contraction caused by climate change. A suspected decline qualifies the species at most for listing as Near Threatened under Criterion C. The rate of decline is not known, and so the species cannot be assessed against Criterion C1. It therefore depends on the subpopulation structure whether the species meets condition 2a. Records on eBird show a wide spread of observations (eBird 2019). Given the overall low dispersal abilities of tapaculos (see e.g. Hermes et al. 2017), we can assume that the species forms several subpopulations, thus not meeting condition 2a(ii). There is no information about the size of each subpopulation. However, assuming that the overall population is closer to the lower end of the estimate, we can very tentatively assume that the largest subpopulation holds fewer than 1,000 mature individuals, or is approaching this threshold. The species is not known to undergo extreme fluctuations, and therefore does not meet condition 2b. Overall, using a very precautionary estimate of the population size and structure, Tatamá Tapaculo may be listed as Near Threatened, approach the threshold for listing as threatened under Criterion C2a(i).

Criterion D – The population size and range are too large to warrant listing as threatened under this criterion, and therefore Tatamá Tapaculo may be considered Least Concern under Criterion D.

Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.

Therefore, it is proposed that Tatamá Tapaculo (Scytalopus alvarezlopezi) be listed as Near Threatened, approaching the threshold for threatened under Criterion B1ab(ii,iii,v); C2a(i). We welcome any comments on this proposed listing and specifically request information on the population size and trend of the species.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic.

*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

eBird. 2019. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, N.Y., U.S.A. http://www.ebird.org (Accessed on 02/05/2019).

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

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. www.iucnredlist.org/technical-documents/categories-and-criteria

Hermes, C.; Jansen, J.; Schaefer, H. M. 2017. Habitat requirements and population estimate of the endangered Ecuadorian Tapaculo Scytalopus robbinsi. Bird Conservation International 28(2): 302-318.

Stiles, F. G.; Laverde, O.; Cadena, C. D. 2017. A new species of tapaculo (Rhinocryptidae: Scytalopus) from the Western Andes of Colombia. The Auk Ornithological Advances 134: 377-392.

Velázquez-Tibatá, J.; Salaman, P.; Graham, C. H. 2013. Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia. Regional Environmental Change 13: 325-248.

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1 Response to The newly described taxon Tatamá Tapaculo (Scytalopus alvarezlopezi) is to be recognized as a species by BirdLife International

  1. Red List Team (BirdLife International) says:

    Preliminary proposal
    Based on available information, our preliminary proposal for the 2019 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 in mid-July, 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 2019 Red List categories will be published on the BirdLife and IUCN websites in December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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