BirdLife species factsheet for Junin Grebe
Junin Grebe is endemic to Peru, where it is restricted to the Lake Junín in the wet-central highlands. The species is found in open water near the centre of the lake, but keeps close to the margins of reed marshes in the breeding season (J. Fjeldså in litt. 2020). Junin Grebe used to be extremely abundant in the past, numbering over 1,000 individuals by the mid 20th century (Morrison 1939, O’Donnel and Fjeldsa 1997). Since then, the species has declined dramatically to about 200 individuals in 1995 (O’Donnell and Fjeldså 1997). The population has stabilised in recent years, when standardised population censuses counted between 217 and 304 individuals between 2001 and 2007, and between 238 and 468 individuals between 2014 and 2019 (A. Chamorro and R. Tito per Engblom 2016a, A. Chamorro per Engblom 2016b, Chamorro and Aucca 2017, Chamorro et al. 2018, Dinesen et al. 2019, A. Chamorro in litt. 2020).
The main threat to the species is the degradation of its habitat with deteriorating water quality due to pollution from mining activities and sewage (Valqui 1994, O’Donnell and Fjeldså 1997). Fluctuations in the water level to supply hydroelectric plants may cause nesting and feeding areas to dry out and breeding to fail (Valqui 1994). Furthermore, unstable climatic conditions linked to El Niño Southern Oscillation events may present a threat to the species (T. Valqui in litt. 1999), as does the increase in trout population in the lake, which may reduce food availability (A. Chamorro in litt. 2020).
Junin Grebe is currently listed as Critically Endangered under Criterion C2a(ii) (BirdLife International 2020). However, the recent stabilization of the population trend 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 has undergone a dramatic population decline in the past. Recent counts however indicate that this decline is historical and that the species has been recovering since the early 2000s. While the species is thought to fluctuate in numbers and recruitment, no declines have been observed, and it appears that the species is overall stable. To account for high levels of uncertainty, we can however precautionarily suspect that the species is undergoing a slow decline over three generations (14.7 years; Bird et al. 2020)*, which does not approach the threshold for listing as threatened under Criterion A. Junin Grebe is hence listed as Least Concern under this criterion.
Criterion B – Both Extent of Occurrence (EOO) and maximum Area of Occupancy (AOO), calculated as a 4 km2 grid over the area of mapped range, are 140 km2. This meets the threshold for listing as Endangered under Criterion B1+2. However, in order to be listed as threatened under this criterion, a species needs to fulfil at least two further conditions.
The species is restricted to one lake and is therefore not severely fragmented sensu IUCN (IUCN Standards and Petitions Committee 2019). The most severe threats to the species are changes in water level, pollution. These threats can potentially impact a relatively large area and consequently a relatively large part of the population at once, with potentially drastic consequences on the population size within one generation length (4.9 years). The number of locations** of occurrence is therefore placed in the band 2-5, and condition a is met at the level of Endangered. Habitat quality is declining throughout the range, and hence condition b(iii) is met. The species does show some fluctuations in population size, however they do not involve tenfold increases or decreases, and hence are not considered ‘extreme fluctuations’ (see IUCN 2001, 2012), and condition c is not met. Junin Grebe consequently qualifies for listing as Endangered under Criterion B1ab(iii)+2ab(iii).
Criterion C – Based on population counts carried out between 2014 and 2019, the population is roughly estimated to number 150-320 mature individuals. This meets the threshold for listing as threatened under Criterion C, however to do so requires further conditions to be met.
All individuals belong to the same subpopulation. Precautionarily, the population is suspected to undergo a slow decline due to the degradation of its habitat. A suspected decline however precludes a listing as threatened under Criterion C. Junin Grebe is therefore considered Near Threatened, approaching the threshold for listing as threatened under Criterion C2a(ii).
Criterion D – The population is estimated to number 140-320 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, Junin Grebe qualifies for listing as Endangered 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 suggested that Junin Grebe (Podiceps taczanowskii) be listed as Endangered under Criteria B1ab(iii)+2ab(iii); D. 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.
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: Podiceps taczanowskii. http://www.birdlife.org (Accessed 16 April 2020).
Chamorro, A.; Aucca, C. 2017. Final report strategic conservation plan for the Junin Grebe (Podiceps taczanowskii) at Lake Junin, Peru. ECOAN.
Chamorro, A.; Salcedo, D.; Guere, S.; Aucca, C.; Palacio, W. 2018. Evaluación poblacional del Podiceps taczanowskii y las aves acuáticas que ocurren en el lago Junín. Asociación Ecosistemas Andinos
Dinesen, L.; Chamorro, A.; Fjeldsa, J.; Aucca, C. 2019. Long-term declines in waterbirds abundance at Lake Juníi, Andean Peru. Bird Conservation International 29(1): 83-99.
Engblom, G. 2016. Nest success of Critically Threatened Junin Grebe. https://www.indiegogo.com/projects/nest-success-of-critically-threatened-junin-grebe#/ (Accessed 22 January 2018).
Engblom, G. 2016. The Junin Grebe may go extinct and we did not even notice. http://kolibriexpeditions.com/blog/junin-grebe-may-go-extinct-and-we-did-not-notice/ (Accessed 22 January 2018).
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.
Morrison, A. 1939. Notes on the birds of Lake Junín, Central Peru. Ibis: 643-653.
O’Donnell, C.; Fjeldsa, J. 1997. Grebes: A global action plan for their conservation.
Valqui, T. 1994. The extinction of the Junín Flightless Grebe? Cotinga: 42-44.