Tolima Dove (Leptotila conoveri): revise global status?

BirdLife species factsheet for Tolima Dove

This discussion was first published as part of the 2019 Red List update. At the time a decision regarding the status of this species was pended, but to enable potential reassessment of this species as part of the 2020 Red List update this post remains open and the date of posting has been updated.

Tolima Dove (Leptotila conoveri) is endemic to Colombia, where it occurs on the eastern slope of the Central Andes and in the East Andes between 1200 and 2500 m. The species is only known from a limited number of sites in the departments of Tolima, Huila, Cauca and Cundinamarca. The population has recently been estimated to number 4,200 individuals in total (Renjifo et al. 2014), which roughly equals 2,800 mature individuals. Tolima Dove is not well known. It inhabits mainly humid forests and bushy forest edges, but is also observed in secondary forest as well as in open, disturbed areas, and occasionally in coffee groves and near houses (Baptista et al. 2019).

The species is in slow decline as a consequence of the loss and degradation of its habitat. Already since the 18th century, forests in the range of Tolima Dove have been logged for agriculture (Stiles et al. 1999). Particularly since the 1950s, habitat clearance and fragmentation has been accelerating, and forests have been converted into plantations or cattle pastures (P. G. W. Salaman in litt. 1999). It is estimated that between 1,900 and 3,200 m, only c. 15% of the natural forest cover is left (P. G. W. Salaman in litt. 1999). Additionally, in parts of the range Tolima Dove is hunted for food.

Currently, Tolima Dove is listed as Endangered under Criterion B1ab(i,ii,iii,v), indicating a very small Extent of Occurrence (EOO) and declines in population size and habitat availability. Integrating the recently discovered population and following IUCN guidelines, the EOO for this species has been re-calculated using a Minimum Convex Polygon (IUCN 2001, 2012, Joppa et al. 2016), as EOO is a measure of the spatial spread of areas occupied by a species, not the actual area it occupies. After re-calculating the EOO for Tolima Dove, this species appears to warrant a change in Red List status. Therefore, we present here our reassessment against all criteria for the species.

Criterion A – Tracewski et al. (2016) measured the forest loss within this species’s range between 2000 and 2012 as c. 5 km2. This roughly equates to a rate of forest loss of 1% over three generations (12.6 years) for this species, with the assumption that habitat loss has continued at the same rate to the present day. Moreover,in parts of its range the species is hunted for food (Renjifo et al. 2014).Therefore, the rate of population decline may be slightly larger than the rate of forest cover decline. However, it is unlikely that the rate of population decline based on habitat loss and hunting approaches the threshold for Vulnerable. Therefore, Tolima Dove may be listed as Least Concern under Criterion A.

Criterion B – Using a Minimum Convex Polygon, the Extent of Occurrence (EOO) has been calculated as 28,100 km2. This value is too large for retaining the species as threatened under Criterion B1. However, it approaches the threshold for listing as threatened (EOO < 20,000 km2); as such it might qualify for listing as Near Threatened. The Area of Occupancy (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.

The species occurs at a high number of locations* in the Central and Eastern Andes. It is considered to be severely fragmented sensu IUCN (IUCN 2012), i.e. the population is shattered in many small, isolated subpopulations. Consequently, Tolima Dove qualifies for condition (a). Based on the slow, but ongoing forest loss, we can infer that AOO, habitat quality and population size are declining, but not fluctuating, thus fulfilling condition (b), but not (c). Therefore, Tolima Dove may be listed as Near Threatened, approaching the threshold for Vulnerable under Criterion B1ab(ii,iii,v).

Criterion C – The population of Tolima Dove is estimated to number c. 4,200 individuals (Renjifo et al. 2014), equating to roughly 2,800 mature individuals. This meets the threshold for listing as Vulnerable under Criterion C (< 10,000 mature individuals). Yet, in order to be listed under Criterion C, other conditions have to be met.

The rate of decline in the species has not been directly estimated, and so it does not warrant listing as threatened under Criterion C1. Instead, the population decline can be inferred from habitat loss (Tracewski et al. 2016). The species is not known to undergo extreme fluctuations, so it does not trigger the conditions for Criterion C2b. It thus depends on the species’s subpopulation structure whether it qualifies for listing as Vulnerable under condition 2a. Based on the fragmentation of its range, we assume that the species forms different subpopulations; hence it does not meet condition a(ii). However, it is highly likely that no subpopulation contains more than 1,000 mature individuals (see Renjifo et al. 2014), which triggers condition 2a(i). Therefore, Tolima Dove may be listed as Vulnerable under Criterion C2a(i).

Criterion D – The population size and range of this species too large to meet the threshold for Vulnerable (< 1,000 mature individuals); hence, the species may be listed as 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 Tolima Dove (Leptotila conoveri) be listed as Vulnerable under Criterion C2a(i). We welcome any comments on this proposed listing.

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).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Baptista, L. F.; Trail, P. W.; Horblit, H. M.; Boesman, P.; de Juana, E.; Garcia, E. F. J.; Sharpe, C. J. 2019. Tolima Dove (Leptotila conoveri). 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. https://www.hbw.com/node/54239 (Accessed 11 April 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

Joppa, L. N.; Butchart, S. H. M.; Hoffmann, M.; Bachman, S. P.; Akçakaya, H. R.; Moat, J. F.; Böhm, M.; Holland, R. A.; Newton, A.; Polidoro, B.; Hughes, A. 2016. Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation Biology 30: 362-370.

Renjifo, L. M.; Gómez, M. F.; Velásquez-Tibatá, J.; Amaya-Villarreal, A. M.; Kattan, G. H.; Amaya-Espinel, J. D.; Burbano-Girón, J. 2014. Libro rojo de aves de Colombia, Volumen I: bosques húmedos de los Andes y la costa Pacífica. Editorial Pontificia Universidad Javeriana & Instituto Alexander von Humboldt, Bogotá D.C., 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.

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2 Responses to Tolima Dove (Leptotila conoveri): revise global status?

  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.

  2. Claudia Hermes (BirdLife International) says:

    Recommended categorisations to be put forward to IUCN

    Based on available information, our proposal for the 2019 Red List is to pend the decision on this species and keep the discussion open until 2020, while leaving the current Red List category unchanged in the 2019 update.
    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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