Blossomcrown (Anthocephala floriceps) is being split: assessment of newly recognised taxa.

BirdLife species factsheet for Blossomcrown

Following a taxonomic reassessment, Blossomcrown (Anthocephala floriceps) has been split into Santa Marta Blossomcrown (A. floriceps) and Tolima Blossomcrown (A. berlepschi). Both species are endemic to Colombia. The newly defined Santa Marta Blossomcrown occurs on the northern and possibly southeastern slope of the Sierra Nevada de Santa Marta at altitudes of between 600 and 1,700 m. Tolima Blossomcrown is found in the Central Andes at altitudes of 1,200-2,300 m in the departments Huila, Tolima and Quindío. Both species inhabit humid premontane forests, but are also found in old secondary growth and occasionally even in coffee plantations and along roads or field edges (Hilty and Brown 1986, Renjifo et al. 2016).

The pre-split taxon was estimated to number 1,500-7,000 mature individuals. The population sizes of the newly defined taxa have not been estimated, but Santa Marta Blossomcrown is described as common to uncommon, while Tolima Blossomcrown is rare (Renjifo et al. 2016, Züchner et al. 2019). Considering the range sizes of the newly split species and the relatively higher rarity of Tolima Blossomcrown, we can tentatively assume that the population size of Santa Marta Blossomcrown is 1/3 of the pre-split size (i.e., 500-2,500 mature individuals), while that of Tolima Blossomcrown is 2/3 of the pre-split size (i.e., 1,000-4,500 mature individuals). These estimates are highly preliminary and may be corrected if more detailed data becomes available.

Both of the newly recognised taxa are under threat from forest loss, as they do not tolerate converted habitats (Züchner et al. 2019). Forests in the Sierra Nevada de Santa Marta have been heavily logged in the past, with only around 15% of the original vegetation remaining (Renjifo et al. 2016). However, an analysis of the rate of forest loss between 2000 and 2012 found that deforestation in the Sierra Nevada de Santa Marta was only minor (per Tracewski et al. 2016), indicating that the area of remaining forests is relatively stable, albeit small and fragmented. Similarly, forests in the Central Andes have been logged for agriculture since the 18th century (Stiles et al. 1999). Mature secondary forest patches are scattered and natural vegetation cover has been reduced by c. 85% between 1,900 and 3,200 m altitude (B. López-Lanús et al. in litt., P. G. W. Salaman in litt. 1998, 1999). Recent rates of deforestation in the area are very low (per Tracewski et al. 2016).

The pre-split species was listed as Vulnerable under Criterion C2a(i) due to its small and declining population, which was thought to consist of many small subpopulations (BirdLife International 2019). However following the taxonomic split, new estimates of range extent and population size suggest that both species warrant a thorough assessment, which is provided below.

Criterion A:

Santa Marta Blossomcrown (A. floriceps)– Thespecies is thought to be declining due to the degradation, fragmentation and loss of its forested habitat. The rate of decline has not been quantified though, and therefore the species cannot be correctly assessed against Criterion A.

Tolima Blossomcrown (A. berlepschi) While the threats this species faces may be considered to be causing population declines, there is no clear evidence of the rate of decline. Therefore, the species cannot be accurately assessed against this criterion.

Criterion B:

Santa Marta Blossomcrown (A. floriceps) – The Extent of Occurrence (EOO) of this species has been calculated at 9,150 km2. This meets the threshold for Vulnerable under Criterion B1 (EOO < 20,000 km2). The Area of Occupancy (AOO) has not been estimated, and therefore the species cannot be assessed against Criterion B2. However, in order to be listed as Vulnerable 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) suggest however that the species forms few, but large, subpopulations. This suggests that the species should not 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 the loss and fragmentation of its forest habitat. Deforestation and illegal logging are site-specific and take place on a relatively small geographic scale; consequently we can conclude that the species is threatened in different areas by different logging events, and thus occurs in several locations*. However, given the small extent of the known range, it is highly likely that the species does not occur in >10 locations*. Therefore, the species meets condition (a). Even though the rate of forest loss is likely low (per Tracewski et al. 2016), the species is assumed to be undergoing a decline in AOO, habitat quality and population size, meeting condition b(ii,iii,v). There is no evidence that the species is undergoing extreme fluctuations, so it does not fulfil condition (c). Consequently, Santa Marta Blossomcrown may be listed as Vulnerable under Criterion B1ab(ii,iii,v).

Tolima Blossomcrown (A. berlepschi) – The EOO of Tolima Blossomcrown has been calculated as 17,550 km2, which meets the threshold for Vulnerable under Criterion B1. The AOO has not been estimated and thus the species cannot be assessed against Criterion B2. However, in order to warrant listing under Criterion B1, at least two further conditions must be met. Records of the species spread over a relatively large area, including several protected areas (eBird 2019). This suggests that the species is not severely fragmented sensu IUCN (IUCN 2012), but forms large subpopulations. The number of locations* has not been quantified. With habitat degradation and loss being the most plausible threat, it is conceivable that the species occurs at c. 10-20 locations. Consequently, Tolima Blossomcrown does not qualify for condition (a), but approaches it. Based on the slow, but ongoing forest loss, we can infer that AOO, habitat quality and population size are declining, thus fulfilling condition (b). Therefore overall, Tolima Dove may be listed as Near Threatened, approaching the threshold for Vulnerable under Criterion B1ab(ii,iii,v).

Criterion C:

Santa Marta Blossomcrown (A. floriceps) – The population size of Santa Marta Blossomcrown is preliminarily estimated at 500-2,500 mature individuals and assumed to be undergoing a slow, but continuing decline based on habitat loss. The rate of decline is not known, and hence the species cannot be accurately assessed against Criterion C1. The number of mature individuals in each subpopulation has not been estimated, but assuming that the overall population size is closer to the lower end of the estimate, they are likely smaller than 1,000 mature individuals. Therefore, Santa Marta Blossomcrown may be listed as Vulnerable under Criterion C2a(i).

Tolima Blossomcrown (A. berlepschi) – The population size of Tolima Blossomcrown is preliminarily estimated at 1,000-4,500 mature individuals and assumed to be undergoing a slow, but continuing decline based on habitat loss. The rate of decline is not known, and hence the species cannot be accurately assessed against Criterion C1. The number of mature individuals in each subpopulation has not been estimated, but assuming that the overall population size is closer to the lower end of the estimate, they are likely smaller than 1,000 mature individuals. Therefore, Tolima Blossomcrown may be listed as Vulnerable under Criterion C2a(i).

Criterion D:

Santa Marta Blossomcrown (A. floriceps)– The population size of Santa Marta Blossomcrown is preliminarily estimated at 500-2,500 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, the species meets the threshold for listing as Vulnerable under Criterion D1. While its AOO has not been assessed, the number of locations* is likely larger than 5, so the species would not warrant listing under Criterion D2.

Tolima Blossomcrown (A. berlepschi)– The population size of this species is preliminarily estimated at 1,000-4,500 mature individuals. This does not meet the threshold for listing as Vulnerable (< 1,000 mature individuals), but approaches it. As such, Tolima Blossomcrown qualifies for listing as Near Threatened, approaching the threshold for listing as threatened under Criterion D1.

Criterion E – To the best of our knowledge there have been no quantitative analyses of extinction risk carried out for either of these species. Therefore, they cannot be assessed against this criterion.

Therefore, it is proposed that Santa Marta Blossomcrown (Anthocephala floriceps) be listed as Vulnerable under Criteria B1ab(ii,iii,v); C2a(i); D1 and Tolima Blossomcrown (Anthocephala berlepschi) be listed as Vulnerable under Criteria B1ab(ii,iii,v); C2a(i). We welcome any comments on this proposed listing and specifically request up-to-date information on the population sizes and trends.

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.

*The term ‘location’ refers to a distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, with the size of the location depending on the area covered by the threatening event. 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. 2019. Species factsheet: Anthocephalus floriceps. http://www.birdlife.org (Accessed 03/05/2019).

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 03/05/2019).

Hilty, S. L.; Brown, W. L. 1986. A guide to the birds of Colombia. Princeton University Press, Princeton.

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.

Renjifo, L. M.; Amaya-Villareal, A. M.; Burbano-Girón, J.; Velázquez-Tibatá, J. 2016. Libro rojo de aves de Colombia, Volumen II: Ecosistemas abiertos, secos, insulares, acuáticos continentales, marinos, tierras altas del Darién y Sierra Nevada de Santa Marta y bosques húmedos del centro, norte y oriente del país. Editorial Pontifica Universidad Javeriana e Instituto Alexander von Humboldt, Bogotá, Colombia.

Stiles, F. G.; Rosselli, L.; Bohórquez, C. I. 1999. New and noteworthy records of birds from the middle Magdalena valley of Colombia. Bulletin of the British Ornithologists’ Club 119: 113-129.

Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.

Züchner, T.; de Juana, E.; Boesman, P.; Sharpe, C. J. 2019. Blossomcrown (Anthocephala floriceps). 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, Spain. https://www.hbw.com/node/55514 (Accessed 03/05/2019).

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1 Response to Blossomcrown (Anthocephala floriceps) is being split: assessment of newly recognised taxa.

  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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