Bogota Rail (Rallus semiplumbeus): revise global status?

BirdLife species factsheet for Bogota Rail

Bogota Rail is endemic to Colombia, where it occurs on the Ubaté-Bogotá plateau in the East Andes. It inhabits savannah and páramo marshes and swamps at an elevation of 2,500-4,000 m. The species is localised, but fairly common in suitable habitat (Taylor and Sharpe 2020). Based on an observed population density of 68 individuals/km2 at Laguna de Tota and under the assumption that 50% of the remaining habitat is occupied, the total population has been estimated at 5,600 individuals (Renjifo et al. 2016). This roughly equates to 3,700 mature individuals. To account for uncertainty, the population is here placed in the band 2,500-9,999 mature individuals.

Recent observations of main populations indicate a decrease in numbers (Renjifo et al. 2016, L. Rosselli in litt. 2020). Bogota Rail is heavily threatened by the loss and degradation of its habitat through drainage of wetlands, agricultural encroachment and subsequent pollution by effluents and agrochemicals, as well as by predation of adults and nestlings by feral dogs (Lonzano 1993, Renjifo et al. 2016, Taylor and Sharpe 2020).

Bogota Rail is currently listed as Endangered under Criteria B1ab(i,ii,iii,iv,v); C2a(i) (BirdLife International 2020). However, new information regarding the population size and distribution range suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all criteria:

Criterion A – The species is undergoing a population decline as suitable habitat within its range is disappearing. The rate of decline has not been quantified, but is here tentatively placed in the band 10-19% over ten years (one generation length being 2.4 years; Bird et al. 2020)*. The species is therefore listed as Least Concern under Criterion A.

Criterion B – The newly calculated Extent of Occurrence (EOO) for this species is 16,600 km2. The maximum Area of Occupancy (AOO), calculated as a 4 km2 grid over the area of mapped range, is 3,144 km2. The EOO therefore meets the threshold for listing as Vulnerable under Criterion B1. However, in order to be listed as threatened under this criterion, a species needs to fulfil at least two further conditions.

The species is thought to form one subpopulation (Renjifo et al. 2016). It is therefore not severely fragmented sensu IUCN (IUCN Standards and Petitions Committee 2019). The most serious threats to the species are the drainage of its wetland habitat, pollution and predation by feral dogs (Renjifo et al. 2016, Taylor and Sharpe 2020). These threats can potentially impact a relatively large area and consequently a relatively large part of the population at once. The number of locations** of occurrence is therefore placed in the band 6-10, and condition a is met at the level of Vulnerable. Habitat degradation is proceeding rapidly within the range, and observations report population declines at several sites (Renjifo et al. 2016, L. Rosselli in litt. 2020). Bogota Rail thus meets condition b(ii,iii,v). There is no evidence of extreme fluctuations in the distribution range or population size, and condition c is not met. Consequently, the species qualifies for listing as Vulnerable under Criterion B1ab(ii,iii,v).

Criterion C – The global population is placed in the band 2,500-9,999 mature individuals. This meets the threshold for Vulnerable under Criterion C; however in order to be listed under this criterion further conditions must be fulfilled.

In parts of the range, the population has been observed to decline (Renjifo et al. 2016, L. Rosselli in litt. 2020). Even though trend data for the rest of the population are lacking, we can infer that the global population is undergoing a decline. The species is restricted to wetlands which are separated by only short distances, and hence it appears that the species forms just one subpopulation (Renjifo et al. 2016). Bogota Rail may therefore be listed as Vulnerable under Criterion C2a(ii).

Criterion D – The population size and range are too large to warrant listing as threatened under Criterion D and therefore, the species is considered Least Concern under this criterion.

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 suggested that Bogota Rail (Rallus semiplumbeus) be listed as Vulnerable under Criteria B1ab(ii,iii,v); C2a(ii). We welcome any comments on the 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. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

**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

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.

BirdLife International. 2020. Species factsheet: Rallus semiplumbeus. http://www.birdlife.org (Accessed 14 April 2020).

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.

IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categories and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Lozano, I. E. 1993. Observaciones sobre la ecología y el comportamiento de Rallus semiplumbeus en el Humedal de la Florida, Sabana de Bogotá.

Renjifo, L. M.; Amaya-Villarreal, A. M.; Burbano-Giron, J.; Velasquez-Tibata, J. 2016. Libro rojo de aves de Colombia, Volumen II: Ecosistemas abiertos, secos, insulares, acuaticos continentales, marinos, tierras altas del Darien y Sierra Nevada de Santa Marta y bosques humedos del centro, norte y oriente del pais. Editorial Pontificia Universidad Javeriana e Instituto Alexander von Humboldt. Bogota, Colombia.

Taylor, B.; Sharpe, C. J. 2020. Bogota Rail (Rallus semiplumbeus), version 1.0. In: del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D. A.; de Juana, E. (eds.). Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.bograi1.01 (Accessed 15 April 2020).

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14 Responses to Bogota Rail (Rallus semiplumbeus): revise global status?

  1. I think the species should not be donwlisted. Historically, most of the information for this species is anecdotal, and after reading this evaluation, I realize this is still the case. Quantitative information on this species is almost non-existent, thus making any evaluation of its conservation status very speculative. For instance, the assumption that gene flow occurs between the local populations inhabiting the small and threatened wetlands of the Bogotá plateau without any –direct or indirect– evidence might prove dangerous for the species’ future. This must be rigorously assessed with most urgency.

    We recently published data on habitat use at one of the main wetlands around the metropolitan area of Bogotá. These data were collected during a 10-month monitoring of the species in ‘La Conejera’ wetland. In this study, we show that habitat associations barely vary across months, and that the species seemingly depend on tall reeds, which are one of the most threatened micro-habitats across the wetlands of the Bogotá plateau. Another study that we will soon publish supports this view, as the association with this type of habitat is disproportionally high in relation with its availability, and does not vary much between the wet and dry seasons. Our data provide quantitative evidence for a high requirement of tall reeds, and suggest that populations inhabiting several wetlands across the Bogotá plateau are probably facing a higher pressure due to drainage and pollution.

    I recommend the following two references to be consulted as supporting information and to be included in the references list:

    Pérez, M. C. & Botero-Delgadillo, E. 2020. Uso de hábitat y comportamiento del Rascón Andino (Rallus semiplumbeus) en el Humedal La Conejera, Colombia. Ornitología Neotropical 31: 1–4.
    ––The PDF is still not available on the journal’s website but I can share a private copy if requested.

    Botero-Delgadillo, E. & Escudero-Páez, S. 2012. Roadside Hawk Rupornis magnirostris predating a Bogotá rail Rallus semiplumbeus, an endemic and endangered species of Colombia. Cotinga 34: 94-95.

  2. I don’t agree with the downlist to vulnerable

    Surveys between in 2020 recorded 25 individuals at Parque Florida. However, we need to do surveys in all bogota wetlands until this is confirmed to be accurate, the number the population

    The species is suspected to be in decline owing to the spread of agriculture, urban construction, new roads, feral dog and cat near the wetlands and because of threats to its habitat, although the likely rate of decline has not been quantified.

    It seems inevitable that bogota wetlands ecosystems will become the battleground for
    those advocating the “progress of civilizing
    processes,” e.g. new house, irrigation
    projects, new big roads or contruction the big factorys. Economic interests oppose those
    who advocate saving a few wetlands to protect
    associated wildlife.
    The Bogota wetland

    The Bogota Rail Project, conducted by Humedales de Bogota and Bogota Birding that to want to do awareness-raising campaigns have been conducted in primary and secondary schools, and postersf. All together we want to do further research is needed to clarify the habitat requirements, breeding biology, range size and population size of the species. Due that is unknow this ecological information for to do the plan management for the conservation the Bogota Rail.

  3. Gabriel Ricardo Rojas Valencia says:

    No me parece conveniente para la protección de esta especie la Tingua bogotana (Rallus semiplumbeus) , especie endemica del altiplano cundiboyacense cuyas poblaciones se han visto seriamente afectadas por diferentes tipos de intervención de su hábitat tales como la reducción en área de los humedales en donde habita la fragmentación de estos y la contaminación de las aguas de estos ecosistemas, por lo tanto considero que no es conveniente para la preservación de esta especie que cambien el estatus de en peligro (EN) a vulnerable (VU).

  4. Darwin Burgos Ramírez says:

    The bird Rallus semiplumbeus is seriously threatened in the region of Cundinamarca and Boyacá, because the ecosystems where it lives are being invaded or surrounded by illegal and legal urban expansions, as well as the contamination of ecosystems because wastewater reaches them. In the present it is difficult to extend with technical arguments and real cases, I respectfully request that the arguments be allowed to be exposed in detail, with cases of ecosystems where the Bogota Tingua is threatened. Thank you. Darwin Burgos Ramirez, Lawyer, advisor and environmental advisor.

  5. Jose Ágreda Arango says:

    I don’t think downlist the status will be good for the wellness of the species. There is no connectivity between Bogota Rail populations, and it needs specific environmental conditions compared with the other Rail species present in the Bogota plateau.

    I think downlist the status would say mistakenly that populations are in recovery, and would not reflect the reality, because the urban expansion of Bogotá (constructions near or even inside the wetlands), the burning of Juncales and drying the marshes and swamps to expand agricultural and cattle raising are main factors that affect the species, and there is no management for this issues.

    Conversely, I believe that the current status of the Bogota Rail can support several projects and management plans to care the wellness of both species and habitat.

  6. Copiado de / copied 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.

    “Rallus semiplumbeus se ha registrado en más de 150 ubicaciones en humedales / lagos de montaña y páramo y en más de 1,200 observaciones principalmente en los últimos diez años. La especie se produce y probablemente se reproduce en humedales tan pequeños como 0.5 ha, pero aún observa un deterioro y degradación continuos del hábitat de humedales dentro de su rango. El EOO confirmado actual de la especie con GeoCat es 16.783 km2 (VU) y un mínimo de AOO 504 km2 (VU). Hay muchos informes de esta especie de humedales muy degradados y hábitat ribereño, incluidos pequeños arroyos dentro de la ciudad de Bogotá y pequeños humedales a través del páramo.

    La mayoría de los observadores de aves en Colombia visitan el Parque La Florida para ver las especies donde la población se ha mantenido estable durante más de 30 años a pesar de la invasión persistente y las actividades humanas en este humedal. Nos preocupa que Bogotá desarrolle áreas de vivienda e industriales alrededor de este humedal, pero hay muchos humedales de tierras altas que están mucho menos amenazados.

    Por lo tanto, hemos revisado las especies aquí contra los criterios relevantes de la Lista Roja;

    Criterio A: la especie está experimentando una disminución de la población a medida que el hábitat de humedales adecuado dentro de su rango está desapareciendo. Estamos de acuerdo con el foro en que la tasa de disminución está tentativamente en la banda del 10 al 19% durante diez años (Preocupación Menor).

    Criterio B: el uso de GeoCat con datos de eBird y otras publicaciones y firmas, el EOO) para esta especie es de 16,783 km2. El AOO es 504 km2 (VU), es mucho menos de lo que BirdLife calculó (3,144 km2). El EOO y el AOO, por lo tanto, alcanzan el umbral para figurar como Vulnerable bajo el Criterio B1ab (i, iii) + 2ab (ii, iii).

    Criterio C: coincidimos en que la población mundial se ubica en la banda de 2.500-9.999 individuos maduros y se ha observado que la población disminuye con la pérdida y degradación del hábitat, pero que existen múltiples subpoblaciones disjuntas en los macizos montañosos y las cuencas hidrográficas separadas del centro oriental. Cordillera. Por lo tanto, sugerimos el Criterio C1 y una disminución del 10% en diez años.

    Respetamos que muchas opiniones preferirían mantener a la especie En Peligro, pero con un creciente cuerpo de información y conocimiento sobre la distribución y población de especies, coincidimos con BirdLife en que Rallus semiplumbeus garantiza su inclusión como Vulnerable bajo los Criterios B1 + 2ab (i, ii, iii); C1.”

    • Sergio Reyes says:

      Una de las poblaciones mas abundantes (al menos 8 individuos en estatus reproductivo) se encuentran en un humedal de Subachoque, Cundinamarca (posiblemente una de las poblaciones a mayor altitud 3200 m.s.n.m) que va a ser dinamitado por un proyecto de Embalse. Esta puede ser una de las ultimas poblaciones al occidente de la sabana de Bogotá, la degradación de la categoría de amenaza contribuiría enormemente para la adjudicación de la licencia ambiental del proyecto.

    • Sergio Reyes says:

      En cuanto al calculo del EOO actual (alrededor de 16 mil km2), ya existen estudios cientificos (Ocampo 2016 y Palacio 2020) que optimizando la metodología geoespacial, calculan un EOO menor de 5000 km2 para la especie (Palacio 2020). Las metodologías mencionadas refinan el EOO con base en los rangos altitudinales, las coberturas y los modelos de ocupación. Por lo tanto sería prudente revisar estos datos y basandose en metodologías más exactas, sugerir los cambios en La Lista Roja IUCN.

  7. Copiado de / copied 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.

    “Rallus semiplumbeus has been recorded at over 150 locations in montane and paramo wetlands / lakes and over 1,200 observations primarily in the past ten years. The species occurs and probably breeds in wetlands as small as 0.5 has, but still seeing a continuing deterioration and degradation of wetland habitat within its range. The species current confirmed EOO using GeoCat is 16,783 km2 (VU) and minimum AOO 504 km2 (VU). There are many reports of this species is heavily degraded wetlands and riparian habitat, including small streams inside the city of Bogota and small wetlands across páramo’s.

    Most birders to Colombia visit Parque La Florida to see the species where the population has been seemingly stable for more than 30 years despite persistent encroachment and human activities on this wetland. We are concerned as Bogota develops housing and industrial areas around this wetland, but there are many highland wetlands that are much less threatened.

    Therefore, we have reviewed the species here against relevant Red List criteria;

    Criterion A – The species is undergoing a population decline as suitable wetland habitat within its range is disappearing. We concur with the forum that the rate of decline is tentatively in the band 10-19% over ten years (Least Concern).

    Criterion B – Using GeoCat with eBird data and other publications and signtings, the EOO) for this species is 16,783 km2. The AOO is 504 km2 (VU), is far less than BirdLife calculated (3,144 km2). The EOO and AOO therefore meet the threshold for listing as Vulnerable under Criterion B1ab(i,iii)+2ab(ii,iii).

    Criterion C – We concur that the global population is placed in the band 2,500-9,999 mature individuals and the population has been observed to decline with habitat loss and degradation, but that there are multiple disjunct subpopulations across montane massifs and separate watersheds of the central Eastern Cordillera. So, we suggest Criterion C1 and decline of 10% over ten years.

    We respect that many opinions would prefer to sustain the species as Endangered, but a growing body of information and knowledge of the species distribution and population we concur with BirdLife that Rallus semiplumbeus
    warrants listing as Vulnerable under Criteria B1+2ab(i,ii,iii); C1.”

  8. I don’t agree with the downlist to vulnerable.
    The wetland ecosystems where this species lives, they do not have protocols for their monitoring and protection.
    Several threats have been mentioned in other comments, but feral dogs have not been mentioned.
    I have records of feral dogs in the area where the Bogota Rail lives.

  9. 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

  10. Red List Team (BirdLife International) says:

    Preliminary proposal

    This species occurs in a small range; its specialised habitat requirements make it susceptible to habitat degradation and loss. The EOO is calculated as a continuous Minimum Convex Polygon, amounting to c.16,600 sqkm. Only a small part of the distribution range is occupied by the species; the AOO is considerably smaller than 2,000 sqkm, meeting the threshold for VU under Criterion B. Uncertainty regarding the population structure do not allow assessing the species against Criterion C2; however the observed declines of up to 19% over ten years qualify it for listing under Criterion C1.

    Based on available information, our preliminary proposal for the 2020 Red List would be to list Bogota Rail as Vulnerable under Criteria B1ab(i,ii,iii,v)+2ab(i,ii,iii,v); C1.

    The change in status is driven by the availability of better data; it should not be mistaken for a genuine recovery of the species. A Vulnerable status indicates that the species is facing a high risk of extinction in the near future, with many threats persisting throughout the range.

    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, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  11. Omar Javier López Gómez says:

    De acuerdo con estadísticas de la Fundación Humedales Bogotá en esta ciudad se han perdido el 98% de las áreas de Humedal. No hay evidencias en el corto mediano o largo plazo de que esta situación vaya a cambiar, por el contrario la constante amenaza de urbanización los seguirá reduciendo con el tiempo. No sé puede cambiar el estatus de la Rallus semiplumbeus solo porque su población esté mejorando en números debido a que sin un hábitat adecuado esos números no perdurarán en el tiempo. También se debe tener en cuenta la fragmentación de su hábitat pues evita una adecuada variedad genética

  12. Loreta Rosselli & F. Gary Stiles says:

    We do not agree with downlisting Rallus semiplumbeus from its present status (EN) to VU based on the following considerations.
    Data on several locations suggest that the rate of decline is considerably higher than the 10-19% that is being considered. Some of the largest populations include Tota and Fuquene. In Tota data from the 80´s and 90’s mention between 100 to 400 individuals (Rosselli et al. 2016) and more recent data mention 50 individuals which would represent a decline of at least 50% . In Fuquene Morales (2007) estimated 200 individuals, our personal observations during two days of censusing in December 2019 give an estimate of 20-50 individuals with large destruction of sedge habitat ongoing representing a 75-90% decline.
    The species has also disappeared in the last decade from Humedal Guaymaral where 6 individuals where present in 2009. Continuous degradation of the city’s wetlands probably has caused population declines and disappearance in other sites without recent data. As an example Tibanica that held more than 30 individuals in 2009 (Rosselli & Stiles 2012) has suffered severe disturbance including virtual elimination of water and several fires. Outside the metropolitan area declines have occurred in la Florida (50%) and the species has disappeared from wetlands in Boyacá (Tunja and Sochagota).
    Connectivity among populations may also be much less than suggested. For example despite considerable habitat improvement in the Cordoba wetland, after one individual visited it for a few months the species has not become established 11 years. In at least three wetlands where the species has disappeared there is no evidence of recolonization in the last decade.
    The AOO is probably much less than calculated, taking into account that only small portions of the wetlands where it occurs are inhabited by the species.
    The population number of 2500-9900 is optimistic. Even if the species has been found in numerous locations, most of the sites we have visited hold less than 10 individuals (frequently less than 5). Therefore the number of locations with observations is not an adequate indication of viable populations. On the other hand, no individuals were detected in a 1 and ½ year survey along the 165km of the upper course of the Bogotá river (Rosselli et al. 2014)
    All this considered the decline and population status of the species is more severe than presented and we suggest it is best kept as EN.

    F. Gary Stiles, Loreta Rosselli

    References
    Rosselli, L. & F.G. Stiles. 2012. Local and Landscape Environmental Factors are Important for the Conservation of Endangered Wetland Birds in a High Andean Plateau. Waterbirds 35:453-469.
    Rosselli, L., A.M. Jaramillo y L.M. Cabrera. 2014. Transformación ambiental a lo largo del curso alto del río Bogotá. Informe Final. Vicerrectoría de Investigaciones. Universidad de Ciencias Aplicadas y Ambientales UDCA. Bogotá.
    Rosselli, L., A. Morales-Rozo y J.D. Amaya-Espinel. 2016. Rallus semiplumbeus, Pp.164-166 en Renjifo, L.M., Amaya-Villarreal, A.M., Burbano-Girón, J. y Velásquez-Tibatá, J., 2016. Libro rojo de aves de Colombia, Vol. 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. Ed. Pontificia Universidad Javeriana e Instituto Alexander von Humboldt. Bogotá, D.C. Colombia.

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