This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines
Lynx Edicions and BirdLife International will soon publish the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.
The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.
Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.
The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), to be incorporated into subsequent Red List updates.
Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.
Kentish Plover Charadrius alexandrinus is being split into C. alexandrinus, C. nivosus and C. dealbatus, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, C. alexandrinus (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.
C. nivosus is a widespread partial migrant in North America, Central America, western South America and the Caribbean, where it mainly occupies coastal habitats, as well as inland waterbodies (del Hoyo et al. 1996). A recent study by Thomas et al. (2012) estimated the total North American population to be 25,869 breeding individuals, with approximately 42% of the breeding population in North America residing at two sites; Great Salt Lake, Utah, and Salt Plains National Wildlife Refuge, Oklahoma. Saalfeld et al. (2013) compared survey counts of adult C. nivosus between 1999-2000 and 2008-2009 on two lakes in the Southern High Plains of Texas that support a large proportion of the regional population, and showed that they decreased by 78% at one saline lake (from 80 adults/survey to 8 adults/survey), although they remained constant at another lake (from 45 adults/survey to 41 adults/survey).
It is suggested that this species could qualify as Near Threatened under criteria A2bc+3c+4bc, on the basis that it might be undergoing a moderately rapid population decline (approaching 30% over 15 years [estimate of three generations]), following evidence of regional declines and on-going threats such as habitat degradation and disturbance (Page et al. 2009, Thomas et al. 2012).
C. dealbatus (originally described as Aegialites dealbatus by Robert Swinhoe in 1870 [Kennerley et al. 2008]) is thought to be a migrant breeder in coastal southern China (Fujian and Hainan provinces), and non-breeding visitor to the coasts of continental South-East Asia, including the Thai-Malay Peninsula, south to Sumatra (Bakewell and Kennerley 2008, Kennerley et al. 2008, Chandler 2009, Rheindt et al. 2011), although previous confusion over taxonomy and on-going identification challenges (despite recent comprehensive reviews of field identification features [e.g. Bakewell and Kennerley 2008, Kennerley et al. 2008]) mean there is still considerable uncertainty over the species’s distribution (Kennerley et al. 2008). It is thought to be rare, but probably also under-recorded (Kennerley et al. 2008).
This species inhabits sandy areas and mudflats, and has been observed during the non-breeding season on areas of reclaimed land that were formerly intertidal mudflats and mangroves, where water had been drained and sand added in preparation for construction, thus creating temporary artificial areas that mimic sandy beaches (Bakewell and Kennerley 2008, Kennerley et al. 2008). Such areas are likely to represent suboptimal habitat and are probably only used for roosting, as they are presumably unsuitable for feeding (Kennerley et al. 2008).
It is unclear whether this species faces any immediate threats during the non-breeding season, as it may benefit from the temporary habitats created through coastal land reclamation (Kennerley et al. 2008). The situation in the species’s breeding range is not known, but extensive degradation of coastal habitats in southern China strongly suggests that breeding areas have been lost. China’s growing tourist infrastructure, particularly in Hainan and Guangxi provinces, may threaten the species if beaches are indeed its preferred habitat during the breeding season (Kennerley et al. 2008).
For the purpose of discerning the likely population trend in this species, it may be assumed provisionally that it has a generation length of 5 years, and thus a three-generation trend period of 15 years (as estimated by BirdLife International for C. alexandrinus). However, it may be appropriate to list this species as Data Deficient, if it is judged that there is insufficient information on its distribution, threats and likely population trend for a robust assessment of its Red List status against the IUCN criteria.
C. alexandrinus (as defined following the taxonomic change, and incorporating all other forms, including nihonensis – the form occurring commonly in East and South-East Asia for which the name dealbatus was mistakenly assigned subsequent to the description of Aegialites [Charadrius] dealbatus [Kennerley et al. 2008, Rheindt et al. 2011]) is mostly migratory and widespread in Eurasia and Africa north of the equator, inhabiting a range of coastal and inland aquatic habitats (del Hoyo et al. 1996). The overall population trend is difficult to discern, and some populations may be in decline (Delany et al. 2009, AEWA 2012, Wetlands International 2013); however, it is likely to be listed as being of Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.
Comments on these suggested categories and further information would be welcomed.
AEWA (2012) Report on the conservation status of migratory waterbirds in the Agreement Area. Fifth edition. Fifth session of the Meeting of the Parties, La Rochelle, France.
Bakewell, D. N. and Kennerley, P. R. (2008) Field characteristics and distribution of an overlooked Charadrius plover from South-East Asia. BirdingASIA 9: 46–57.
Chandler, R. (2009) Shorebirds of the Northern Hemisphere. London, UK: Christopher Helm.
Delany, S., Scott, D., Dodman, T. and Stroud, D. (eds.) (2009) An Atlas of Wader Populations in Africa and Western Eurasia. Wageningen, The Netherlands: Wetlands International.
del Hoyo, J., Elliott, A. and Sargatal, J. (1996) Handbook of the birds of the world, Vol 3: Hoatzin to Auks. Barcelona, Spain: Lynx Edicions.
Kennerley, P. R., Bakewell, D. N. and Round, P. D. (2008) Rediscovery of a long-lost Charadrius plover from South-East Asia. Forktail 24: 63–79.
Page, G. W., Stenzel, L. E., Page, G. W., Warriner, J. S., Warriner, J. C. and Paton, P. W. (2009) Snowy Plover (Charadrius nivosus). In Poole, A. (ed.) The Birds of North America Online. Ithaca, NY: Cornell Lab of Ornithology. Downloaded from: http://bna.birds.cornell.edu/bna/species/154: doi:10.2173/bna.154.
Rheindt, F. E., Székely, T., Edwards, S. V., Lee, P. L. M., Burke, T., Kennerley, P. R., Bakewell, D. N., Alrashidi, M., Kosztolányi, A., Weston, M. A., Wei-Ting Liu, Wei-Ting Lei, Yoshimitsu Shigeta, Javed, S., Zefania, S. and Küpper, C. (2011) Conflict between Genetic and Phenotypic Differentiation: The Evolutionary History of a ‘Lost and Rediscovered’ Shorebird. PLoS ONE 6(11): e26995. doi:10.1371/journal.pone.0026995.
Saalfeld, S. T., Conway, W. C., Haukos, D. A. and Johnson, W. P. (2013) Recent declines in apparent survival and survey counts of snowy plovers breeding in the southern high plains of Texas. Wilson Journal of Ornithology 125(1): 79–87.
Thomas, S. M., Lyons, J. E., Andres, B. A., T-Smith, E. E., Palacios, E., Cavitt, J. F., Royle, J. A., Fellows, S. D., Maty, K., Howe, W. H., Mellink, E., Melvin, S. and Zimmerman, T. (2012) Population Size of Snowy Plovers Breeding in North America. Journal of the Waterbird Society 35(1): 1–14.
Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis 152: 724–746.
Wetlands International (2013) Waterbird Population Estimates. Retrieved from: wpe.wetlands.org on Wednesday 3 Apr 2013.