|Red List Category & Criteria:
||Jiang, Y., Di, L., Aldridge, D. & McIvor, A.
||McIvor, A., Smith, K. & Seddon, M.B.
Margarya mansuyi is known to be present in Lake Xingyun (34 km²) and Lake Qilu (37 km²) and was found in both lakes in recent years; it is certainly now extinct in Lake Yilong and has not been found in recent surveys of Lake Datunhai and Lake Dianchi. Its current known range area therefore
falls within the thresholds for Endangered under criterion B (for the two lakes—two locations—where the species' presence is currently confirmed). The main threats to the species include water abstraction, pollution and a tendency for these small lakes to dry out.
This species was assessed by Liu Yueing and Wu Min as Vulnerable for the Chinese Red List (2004). Their assessment was also based on the criterion B, but eight locations were estimated for the species. Three of these locations, however, were errors and recent survey data shows that the species is now extinct or likely extinct in three more of these lakes (lakes Yilong, Datunhai and Dianchi).
|Range Description:||This species occurs in Yunnan Province, China, where it occurs in Lake Xingyun (34 km²) and Lake Qilu (37 km²). The species was found to still be present in these lakes in 2006 and 2007 respectively. Previously it was known from Lake Yilong, Lake Dianchi, and Lake Datunhai (also called Lake Datun). Relatively recently it was known from Lake Yilong (32 km²) and Lake Datunhai (12 km²). However in 1983, Lake Yilong dried up for about two months, and the species is now considered extirpated from this lake. Lake Datunhai did not dry up but became very shallow. Both these lakes were surveyed in 2006 and this snail was not found (Du Lina, pers. comm. 2008), and another survey of Lake Datunhai in May 2008 by Du Lina also did not find it, so it is probably no longer present in there. Du Lina also surveyed Lake Dianchi in May 2008 and could not find the species; it has probably also been extirpated from there. |
The species was previously listed in the China Red List (2004) as also occurring in Lakes Fuxian and Erhai, but Du Lina believes these records to be errors.
|♦ Estimated area of occupancy (AOO) - km2:||0-50||♦ Continuing decline in area of occupancy (AOO):||Yes|
|♦ Extreme fluctuations in area of occupancy (AOO):||No||♦ Estimated extent of occurrence (EOO) - km2:||71|
|♦ Continuing decline in extent of occurrence (EOO):||Yes||♦ Extreme fluctuations in extent of occurrence (EOO):||No|
|♦ Number of Locations:||2||♦ Continuing decline in number of locations:||Yes|
|♦ Extreme fluctuations in the number of locations:||No|
|Range Map:||Click here to open the map viewer and explore range.|