Relict Gull, Larus relictus, is a migratory gull, breeding at localities in Kazakhstan, Russia, Mongolia and China (e.g. Rubini and Berezovikov 2002, He Fen-qi and Ren Yong-qui 2006). Breeding sites are found in the arid-steppe zone on islands in saline and slightly-saline lakes. These lakes have fluctuating water levels and nesting may not occur if lakes dry up, if islands become attached to the shore or if the water level becomes too high and makes the island too small and overgrown with vegetation. The species migrates away from breeding sites in the non-breeding season, and its non-breeding range is poorly known, though it is documented from South Korea and China at estuarine mud- and sand-flats (P. Holt in litt. 2011, 2012, Q. Bai and M. Xunqiang in litt. 2016), as well as inland on the northern flank of the Qinghai-Tibet plateau, China.
The species is threatened during the breeding season by climate change, as increasing aridisation and vegetation changes have been predicted in its range (Tchebakova et al. 2009). Human disturbance is another threat, for instance Taolimiao-Alashan Nur (formerly thought to hold up to 3,000 pairs [He Fen-qi and Qiao Zhenzhong in litt. 2004]) was recently abandoned, likely a result of increased tourist activity, unsustainable water use and drought (He Fen-qi in litt. 2011). During the non-breeding season pollution and development of coastal areas are thought to be serious threats to the species (P. Holt in litt. 2011).
Its population was estimated at 12,000 individuals by Rose and Scott (1997). However, up to 5,000 pairs have been recorded at Honjian Nur Lake, China (He Fen-qi and Ren Yong-qui 2006) and so the global population size is likely >>10,000 mature individuals. Because the species is migratory there is the possibility that individuals may interact with one another during the non-breeding season, and so the population could be said to contain only one sub-population. However, given the paucity of knowledge regarding the non-breeding distribution of this species, and the presence of an inland non-breeding population, it is tentatively suggested that species consists of more than one sub-population. Population trends are also difficult to determine with some colonies undergoing dramatic declines (Taolimiao-Alashan Nur), while other colonies are increasing (e.g. Honjian Nur Lake), but given the threats that may be affecting this species, it may be conservative to consider the species to be in decline.
Relict Gull is currently listed as Vulnerable under criterion D2 on the basis that it breeds at only a limited number of locations* that could be strongly affected by climate change in the future (see BirdLife International 2017). To qualify as Vulnerable under criterion D2 a species must occur at 5 or fewer locations or have an Area of Occupancy of <20km2, and there be a plausible threat that could drive the species to Critically Endangered or Extinction in a very short time (see IUCN 2001, 2012). However, the number of breeding locations does not meet the threshold for Vulnerable (one locality in Kazakhstan [Rubini and Berezovikov 2002]; one in Russia; several in Mongolia; and at least one in China at Honjian Nur Lake, Shaanxi [He Fen-qi and Ren Yong-qui 2006]), and while its Area of Occupancy has not been directly calculated, it is unlikely to be <20km2. Therefore, Relict Gull likely does not qualify as Vulnerable under criterion D2. Instead, given the number of locations has currently been estimated at 6-10, it is suggested that the species be instead listed as Near Threatened under criterion D2.
We welcome any further information and comments regarding this proposed downlisting.
*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. 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).
BirdLife International. 2017. Species factsheet: Larus relictus. Downloaded from http://www.birdlife.org on 15/03/2017.
He Fen-qi; Ren Yong-qi. 2006. Alternative choosing of breeding sites of those Ordos Relict Gulls. China Nature 4: 16-17.
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission.
IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.
Rubini, B.; Berezovikov, N. N. 2002. The fluctuation of breeding numbers of Relict Gull Larus relictus on Lake Alakol (SE Kazakhstan): a review of surveys from 1968 to 2001. Acrocephalus 23(115): 185-188.
Tchebakova, N. M.; Parfenova, E.; Soya, A. J. 2009. The effects of climate, permafrost and fire on vegetation change in Siberia in a changing climate. Environmental Ressearch Letters 4.