Archived 2020 topic: Piping Plover (Charadrius melodus): revise global status?

BirdLife species factsheet for Piping Plover

Piping Plover (Charadrius melodus) is a shorebird breeding along the Atlantic coast of North America and further inland along rivers and wetlands (Elliott-Smith and Haig 2020). During the non-breeding season, it migrates south to winter on the beaches and mudflats between south-eastern USA and Yucatan, and occasionally on islands in the Caribbean (Elliott-Smith and Haig 2020). The population is estimated to number 8,400 mature individuals (Partners in Flight 2019), equating to roughly 12,000-13,000 individuals.

Major threats to the species include habitat loss and degradation due to droughts, inappropriate water and beach management, dredging, developments and shoreline stabilisation, coastal flooding caused by climate change, and also nest predation by avian and mammalian predators (Hecht 1995, Elias et al. 2000, Boettcher et al. 2007, Elliot-Smith and Haig 2020). Piping Plover has been undergoing a decline over the last five decades (Meehan et al. 2018, Partners in Flight 2019), but there is some uncertainty regarding the rate of decline and short-term population trends. There is evidence that following intense conservation action, the population increased at least locally by up to 70% since 1991 (Elliott-Smith et al. 2009).

Piping Plover is currently listed as Near Threatened, approaching the threshold for listing as threatened under Criterion C2a(i) (BirdLife International 2020). However, new information regarding population trend suggests that the species may warrant a change in Red List status. Therefore, the species be re-assessed against all criteria:

Criterion A – The species has been undergoing a large, significant decline over the last five decades, with an estimated annual decline of 1.86% (Partners in Flight 2019). This roughly equates to a decrease of 20% over three generations (11.7 years; Bird et al. 2020*). Audubon Christmas Bird Count shows a similar rate of decline of 2.39% per year (Meehan et al. 2018), equating to 25% over three generations. Short-term trends are inconclusive however, as there are hints that the species has been stable or even locally increasing as a result of conservation management over the last two decades (Elliott-Smith and Haig 2020). Applying a conservative approach, unless more recent data becomes available, we can place the rate of decline in the band 20-29% over three generations. Thus, Piping Plover may be considered Near Threatened, approaching the threshold for listing as threatened under Criterion A2abc.

Criterion B – The species’s range and Extent of Occurrence (EOO) is too large to warrant listing as threatened under Criterion B (EOO breeding = 6,090,000 km2, EOO non-breeding = 4,370,000 km2); thus Piping Plover qualifies as Least Concern under this criterion.

Criterion C – The global population numbers 8,400 mature individuals and is estimated to decline at 20-29% over three generations (Meehan et al. 2018, Partners in Flight 2019). Due to the species’s migratory nature, all individuals are able to get in contact with each other, and are thus considered to belong to just one subpopulation. Piping Plover therefore qualifies for listing as Vulnerable under Criterion C1+2a(ii).

Criterion D – The population size and range are too large to warrant listing as threatened under Criterion D and thus Piping Plover qualifies as 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 Piping Plover (Charadrius melodus) be listed as Vulnerable under Criterion C1+2a(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).

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: Charadrius melodus. http://www.birdlife.org (Accessed 11 March 2020).

Boettcher, R.; Penn, T.; Cross, R. R.; Terwilliger, K. T.; Beck, R. A. 2007. An overview of the status and distribution of Piping Plovers in Virginia. Waterbirds 300: 138-151.

Elias, S. P.; Fraser, J. D.; Buckley, P. A. 2000. Piping Plover brood foraging ecology on New York Barrier Island. Journal of Wildlife Management 64: 346-354.

Elliott-Smith, E.; Haig, S. M. 2020. Piping Plover (Charadrius melodus), version 1.0. In: Poole, A. F. (ed.) Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.pipplo.01 (Accessed 11 March 2020).

Hecht, A. 1995. Coastal plovers on the rise. Endangered Species Technical Bulletin 20: 14-16.

Meehan, T. D.; LeBaron, G. S.; Dale, K.; Michel, N. L.; Verutes, G. M.; Langham, G. M. 2018. Abundance trends of birds wintering in the USA and Canada, from Audubon Christmas Bird Counts, 1966-2017, version 2.1. National Audubon Society, New York, New York, USA.

Partners in Flight. 2019. Avian Conservation Assessment Database, version 2019. http://pif.birdconservancy.org/ACAD.

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5 Responses to Archived 2020 topic: Piping Plover (Charadrius melodus): revise global status?

  1. Brad Andres says:

    We are currently updating the North American shorebird population sizes and trends paper (Andres et al. 2012). I suggest using species-specific surveys to estimate trends for recognized populations.

    Numbers of C. m. melodus breeding adults during 2014–2018 averaged 3,758 (calculated as pair count multiplied by two; USFWS 2019). The Bahamas has recently been discovered to support >1/3 of the wintering population (Gratto-Trevor 2016) of this population. The population has undergone a significant large increase from a low of 1,580 adults in 1986. However, the increase has slowed in the last two decades and the recovery goal has not yet been achieved.

    Between 2014 and 2018, an average of 147 plovers (C. m. circumcinctus) bred in the Great Lakes region of the U.S. and Canada (USFWS unpubl. data). Because of intensive management, the population has undergone a significant large increase from a low of 34 individuals in 1981. With an increased population, breeding plovers have been expanding into areas of their historical range that have not been occupied in recent decades. However, recovery goals for the population have not yet been achieved.

    From the 2016 international breeding plover census, about 3,500 plovers (C. m. circumcinctus) were observed breeding within the Prairie Canada/U.S. Northern Great Plains region (Elliot-Smith 2015), which is 56% higher than the previous survey (2011) but is similar to the average of the past five surveys (3,320 plovers, 1991–2011). Because populations on the Great Plains fluctuate with wet-dry cycles, trends can be difficult to determine, particularly because not as many sites are surveyed annually as on the Atlantic coast and in the Great Lakes. Undoubtedly, many birds were missed in cropland and other non-surveyed, typically inappropriate habitat. 40-year trends in the Christmas Bird Count in Texas indicates a 3.43% decline per year (95% CI = -5.75, -1.37). The major of wintering plovers on the Texas coast breed in the Great Plains. Total population size is 7,405 breeding adults. Trend might be considered stable over all populations. Most recent population size estimates seem to warrant vulnerable. Less sure that trend warrants uplisting. Note that Piping Plovers on the Atlantic coast are conservation dependent, through use of exclosures, beach stewards, etc. Without these efforts the population would almost certainly decline.

  2. In addition to the comments stated above, note that Piping Plovers in the Great Lakes region are also highly conservation dependent, through use of exclosures, beach stewards, and a captive rearing program. Without continuation of these efforts (either all or in part), the population would most likely decline.

    Also, a recent paper (Saunders et al. 2018 Journal of Applied Ecology 55:1380-1392) provides a population viability analysis for the Great Lakes Piping Plover population. This paper demonstrates that without accounting for the expanding merlin population (a primary predator of plovers in the Great Lakes region), population viability is underestimated. By incorporating an index of merlin abundance, the quasi-extinction probability (less than or equal to 15 breeding pairs remaining) is now estimated as ~12% over a 10-year period.

  3. 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

  4. Red List Team (BirdLife International) says:

    Preliminary proposal

    Information submitted during the Forum process allows a more detailed assessment against Criteria A and C. Based on targeted surveys of recognized populations it appears that population declines are historical and the population is increasing slowly. However, it seems that the population increase is largely a result of intensive conservation action and thus it is likely that positive trends would reverse again, if conservation action were to stop. Due to its high conservation-dependence, a listing as Near Threatened is justified.

    Based on available information, our preliminary proposal for the 2020 Red List would be to list Piping Plover as Near Threatened, approaching the threshold for listing as threatened under Criterion A3ce.

    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.

  5. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    The final categorisation for this species has changed. Piping Plover is recommended to be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion D2.

    Many thanks for everyone who contributed to the 2020 GTB Forum process. 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.

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