Black-necked Crane (Grus nigricollis) breeds on the Qinghai-Tibetan plateau (China), with a small population in adjacent Ladakh in India (Li 2019). Three isolated wintering populations have been identified at lower altitudes in China and Bhutan: the Eastern population winters in northeastern Yunnan and northwestern Guizhou; the Central population winters in northwestern Yunnan; and the Western population winters in south-central Tibet and in Bhutan. The global population is estimated at 10,000-10,200 individuals (Li 2019), which roughly equates to 6,600-6,800 mature individuals.
Black-necked Crane is exclusively alpine and is found in bog meadows, riverine marshes or along riverbanks or large water bodies. This makes it susceptible to the loss and degradation of habitat. The species is threatened by droughts and desertification of wetlands related to climate change, as the melting of glaciers and the degradation of permafrost are expected to lead to water shortages and extensive loss of shallow wetlands in the long-term (Farrington 2009, Qiu 2012). In the short-term, however, glacier melt seems to be favourable to the species, as it generates new wetland breeding habitat (J. Austin in litt. 2020). Further threats include the intensification of agriculture and human population growth. Nevertheless, the species is responding well to conservation action throughout its range, including the establishment of large networks of protected areas in China and India (Li 2019, Archibald et al. 2020, J. Austin in litt. 2020).
Uncertainty over the current population trend and the numerous threats facing the species had led to the cautious inference of an ongoing decline; hence the species was classified as Vulnerable under Criterion C2a(ii) when last assessed in 2016 (BirdLife International 2020). However, recent population monitoring has found that declines have stopped and the species appears to be recovering (Li 2019, Archibald et al. 2020, J. Austin in litt. 2020). Given these new findings, the species may warrant a change in Red List status; thus it is here re-assessed against all criteria:
Criterion A – In the past, Black-necked Crane was thought to be declining at a rate of 1-9% over three generations (39.3 years; Bird et al. 2020)*. Recent monitoring however indicates that declines have stopped; the population has stabilised during 2000-2010 and is currently stable or even slightly increasing (Li 2019). Previous declines have not been sufficient to list the species as threatened under Criterion A1 or A2. At present, the expansion of suitable habitat due to increased rates of glacier melt is considered one of the drivers of the favourable status of the species over the short term; although there is the possibility that future hydrological changes driven by climate change may adversely impact the species, as continuing glacier melt and permafrost degradation could lead to a loss of shallow wetlands over the long term. However, Black-necked Crane has also benefitted from the creation of protected areas in China and India. While there may be concern about the future direction of climate change-driven habitat change on the Qinghai-Tibetan plateau, current evidence is that an excellent conservation response (especially in the wintering areas) has successfully reduced the extinction risk of the species. Hence, with at least a decade of stability and low risk of rapid population declines in the near future, Black-necked Crane is proposed to be listed as Least Concern under Criterion A.
Criterion B – The Extent of Occurrence (EOO) from a Minimum Convex Polygon around the most restricted seasonal range is 1,790,000 km2; the Area of Occupancy (AOO) has not been estimated. In the absence of a continuing decline in the number of mature individuals or in range (which is thought most likely to have increased in the non-breeding season due to the designation of additional protected areas), the species does not meet the necessary subcriteria for listing as threatened under Criterion B. As such, it is proposed to be listed as Least Concern under this criterion.
Criterion C – The global population is estimated at roughly 6,600 – 6,800 mature individuals, but in the absence of a continuing decline, the species would not qualify for listing as threatened under Criterion C. As such, it is proposed that Black-necked Crane should be listed as Least Concern under this criterion.
Criterion D – The global population and range size are too large to warrant a listing as threatened under Criterion D. Black-necked Crane is therefore 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 proposed that Black-necked Crane (Grus nigricollis) be listed as Least Concern. The available evidence suggests that the species probably qualified for downlisting from Vulnerable to Near Threatened between 2000 and 2004, and from Near Threatened to Least Concern between 2008 and 2012. We welcome any comments on this proposed listing and on the proposed timing (to inform the coding of genuine changes in status for the Red List Index).
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.
Archibald, G. W.; Meine, C. D.; Kirwan, G. M. 2020. Black-necked Crane (Grus nigricollis), 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.blncra1.01 (Accessed 25 May 2020).
Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Şekercioğlu, Ç. H., Butchart, S. H. 2020. Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology, online first view.
BirdLife International. 2020. Species factsheet: Grus nigricollis. http://www.birdlife.org (Accessed 19 May 2020).
Farrington, J. D. 2009. Impacts of Climate Change on the Yangtze Source Region and Adjacent Areas. WWF and the China Meteorological Press, Beijing, China.
Li, F. 2019. Species Review: Black-necked Crane (Grus nigricollis): IUCN SSC Crane Specialist Group – Crane Conservation Strategy. In: Mirande, C. M.; Harris, J. T. (editors) 2019. Crane Conservation Strategy. International Crane Foundation, Baraboo, Wisconsin, USA.
Qiu J. 2012. Thawing permafrost reduces river runoff: China’s Yangtze River is receiving less water as climate warms. Nature News, 6 January 2012. http://www.nature.com/news/thawing-permafrost-reduces-river-runoff-1.9749?WT.ec_id=NEWS-20120110 (Accessed 19 May 2020).