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 the effects of hunting together with habitat loss (see 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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9 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.

  3. There is new information at the website of the Colombian NGO SELVA that I hope can be helpful in further evaluating the conservation status of Tolima Dove. This information will be soon published in the scientific literature, but in the meantime, it can be accessed in the form of public reports and other documents such as conservation plans. Through its project “Identifying and conserving priority areas for the Tolima Dove (Leptotila conoveri) and Yellow-headed Brushfinch (Atlapetes flaviceps) in Colombia”, funded by American Bird Conservancy, SELVA generated a huge amount of field data that allowed to estimate the species’ AOO based on climatic niche models and occupancy models (estimated at 5025 km2). In addition, density estimates at different localities were reported for the very first time.

    All this information was summarized in a conservation plan for the species. I really hope this document is consulted and considered for taking a more informed decision. The link to the English version of the species’ conservation plan can be found at:
    http://selva.org.co/en/research-programs/threatened-species/leptotila-and-atlapetes/

    More documents (in Spanish) with more detailed information can also be found at:
    http://selva.org.co/es/areas-de-investigacion/especies-amenazadas/leptotila-y-atlapetes/

  4. Red List Team (BirdLife International) says:

    The rate of decline under Criterion A is measured over the longer of 10 years or three generation lengths of the species. The generation length for Tolima Dove has recently been recalculated to 4.7 years (Bird et al. 2020), meaning that trends should be assessed over 14.1 years (three generations) under Criterion A.
    Global Forest Change data on tree cover loss up to 2019 have now been released and made available via Global Forest Watch. Based on these data, over three generations (14.1 years) approximately 4.3% of tree cover with >30% canopy cover was lost from within the species’s range (Global Forest Watch 2020).

    References:
    Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.
    Global Forest Watch. 2020. Interactive Forest Change Mapping Tool. http://www.globalforestwatch.org

  5. Alex Cortés, Juan Carlos Luna, Andrea Borrero, y Juan Lazaro Toro (2020) Evaluación de especies de aves amenazadas en Colombia / Evaluation of Threatened Birds Species in Colombia. Conservación Colombiana 27: 3-31:

    “Desde alrededor de 2010, con una mayor seguridad y confianza en todo el rango de especies del valle medio y alto del Magdalena (históricamente una región peligrosa con conflictos significativos), las actividades de observación de aves y ornitológicas aumentaron significativamente. Por el contrario, hubo una explosión de avistamientos y nuevas ubicaciones para Leptotila conoveri al igual que con los demás endémicos de la Cordillera Central / Magdalena como Atlapetes flaviceps, ambos que tradicionalmente se consideraban raros y localizados y considerados con el estatus por IUCN de En Peligro (desde 1994).

    Leptotila conoveri en eBird muestra 758 observaciones en >160 sitios, principalmente en los últimos diez años. Junto con los nuevos datos de Escudero-Páez et al (2018) GeoCat da el EOO como 37,054 km2 (NT). El AOO de 5.025 km2 (NT) de Escudero-Páez et al (2018) también es muy útil (gran investigación de SELVA).

    Avistamientos y estudios realizados por ProAves, SELVA, y muchos otros han demostrado que las especies toleran una amplia variedad de tipos de bosque incluyendo vegetación secundario joven, jardines y áreas agroforestales tales como cultivos de café. Se ha documentado que la especie anida en cafetales, así como en otros hábitats muy intervenidos. Es seguro decir que la especie está mucho más abundante de lo que se consideró originalmente (> 10,000 individuos maduros) y con poco riesgo de extinción.

    Basado en la densidad de población de L. conoveri que se ha estimado en 20.6 individuos / km2 cuando se promedió en 10 sitios distribuidos en todo el rango de especies, incluidos algunos sitios que alcanzan 56 individuos / km2 (Escudero-Páez et al 2018). Usar la estimación promedio de 20.6 individuos / km2 con el AOO de 5.025 km2 daría una población de >100,000 individuos. Creemos que es una sobreestimación, pero no poco realista.

    Escudero-Páez et al (2018) también observa extensas áreas protegidas existentes en todo el rango de especies (11% del rango) mientras que la especie se adapta a bosques degradados y algunos hábitats no forestales. Es seguro decir que la especie es mucho más abundante de lo que se pensó originalmente y con poco riesgo de extinción.

    Evaluamos Leptotila conoveri de la siguiente manera:

    Criterio A – Con base en nueva información y su adaptación a una amplia variedad de hábitats no amenazados debería incluirse a Leptotila conoveri como Preocupación Menor.

    Criterio B: La especie se encuentra en un gran número de lugares con flexibilidad y tolerancia al hábitat degradados, Leptotila conoveri califica como Casi Amenazada, B1+2ab ( ii, iii, i v ).

    Criterio C: se estima que la población de Leptotila conoveri es > 100,000 individuos y alcanza el umbral para ser catalogada como Preocupación Menor.

    Por lo tanto, ProAves recomienda que Leptotila conoveri sea listada como Casi Amenazada.”

  6. English translation from:
    Alex Cortés, Juan Carlos Luna, Andrea Borrero, y Juan Lazaro Toro (2020) Evaluación de especies de aves amenazadas en Colombia / Evaluation of Threatened Birds Species in Colombia. Conservación Colombiana 27: 3-31.

    “From around 2010 with increased security and safely across the species range of the mid and upper Magdalena valley (historically a dangerous region with significant conflict), birding and ornithological activities significantly increased. Conversely, there was an explosion of sightings and new locations for Leptotila conoveri as with the other Central Cordillera / Magdalena valley endemic Atlapetes flaviceps – both that were traditionally considered rare and localized and assigned IUCN Endangered status (since 1994).

    Leptotila conoveri in eBird notes 758 observations at >160 sites, mostly in the last ten years. Together with new data from Escudero-Páez et al (2018) GeoCat gives the EOO as 37,054 km2 (NT). The AOO of 5,025 km2 (NT) from Escudero-Páez et al (2018) is also very helpful (great work from SELVA).

    Sightings and studies by ProAves, SELVA and others have shown that the species tolerates a wide variety of forest types including young secondary growth, gardens and agroforestry areas such as coffee plantations. The species has been documented to nest in coffee plantations as well as other heavily intervened habitats.

    Based on the population density of Tolima Dove that has been estimated at 20.6 individuals/km2 when averaged across 10 sites distributed throughout the species range, including some sites reaching 56 individuals/km2 (Escudero-Páez et al 2018). Using the average estimate of 20.6 individuals/km2 with the AOO of 5,025 km2 would give a population of >100,000 individuals. We think that is an over-estimate, but not unrealistic.

    Escudero-Páez et al (2018) also notes extensive existing protected areas across the species range (11% of range) while the species is adapted to degraded forest and some non-forest habitats. It is safe to say the species is far more abundant than originally considered and at little risk of extinction.

    We assess L. conoveri as follows:

    Criterion A –Based on new information and its adaption is a wide variety of non-threatened habitats would list L. conoveri as Least Concern.

    Criterion B – The species occurs at a high number of locations with flexibility and tolerance of degraded forest L. conoveri qualifies as Near Threatened, B1+2ab(ii,iii,iv).

    Criterion C – The population of Leptotila conoveri is estimated to number >100,000 individuals and meets the threshold for listing as Least Concern.

    Therefore, ProAves recommends that Leptotila conoveri be listed as Near-threatened.”

  7. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  8. Red List Team (BirdLife International) says:

    Preliminary proposal

    The following decision is based on a newly mapped range (as per Escudero-Paez et al. 2018) and an updated Extent of Occurrence (EOO) exceeding 39,000 sqkm. Furthermore, assuming that the number of individuals may exceed 100,000 (Fundación ProAves in litt. 2020), the number of mature individuals is likely to fall in the band of 50,000-99,999. Thus, due to an increase in sightings, tolerance to a wide variety of forests, and extensive occurrence across protected areas, the species no longer qualifies for threatened or near-threatened categories.

    Based on available information therefore, our preliminary proposal for the 2020 Red List would be to list the Tolima Dove as Least Concern.

    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 the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021 (information on the IUCN Red List update process can be found here), following further checking of information relevant to the assessments by both BirdLife and IUCN.

  9. Sara Lara says:

    Like Atlapetes flaviceps we note that moving it from Endangered to Least Concern instantly is too extreme. We recognize this is a marginal line case and again my team recommends that it be prudent to consider the species as Near-threatened for now. Thanking you.

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