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Bythinella markovi 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Littorinimorpha Hydrobiidae

Scientific Name: Bythinella markovi Glöer & Georgiev, 2009

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2010
Date Assessed: 2009-11-20
Assessor(s): Georgiev, D.
Reviewer(s): Abdul Malak, D., Fehér, Z., Tomovic, J., Seddon, M.B., Glöer , P. & Cuttelod, A.
Justification:
Bythinella markovi is endemic to Bulgaria, and is considered Critically Endangered (CR) B1ab(iii)+2ab(iii) due to its restricted range and continuing degradation of its habitat as from pollution and human disturbance. It only occurs in one cave, less than 200 m, with no evidence that it can be found at nearby locations.  There is pollution at the site and the cave is being disturbed by cavers and for tourism.

Geographic Range [top]

Range Description:This species is endemic to Bulgaria, where it is found in the Gargina Dupka cave in Dobrostan karst system (West Rhodope Mountains). The area of the cave system is very short, only 200 metres.
Countries occurrence:
Native:
Bulgaria
Additional data:
Estimated area of occupancy (AOO) - km2:4
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Live specimens were collected 50 metres from the cave’s entrance, where the environmental conditions were characteristic for a cave. Living snails were found along the whole stretch of the stream up to the surfacing of the stream from a narrow cave whole, close to the cave’s end. Taking 117 at random 2x2 cm2 square samples from under stone surfaces in the stream, we collected a total of 16 individuals of B. markovi which showed a relative density of 0.14 individuals per 2 cm2 (min-max = 0-2 individuals), (Gregoriev, pers. comm., 2009).
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:This species is troglobite, i.e. is adapted to live permanently in cave environment. The cave has two closely situated entrances and a stream that flows out from the lower one. There is a catchment of its waters at the cave antechamber which drives away about 70% of the stream for drinking needs. The total cave length is 524 m. The specimens live under stones in a limestone cave stream, which has shallow (at average around 10-15 cm) and calm waters in winter and summer, and deep (max about 1-1.5 m) and fast running ones at rainy seasons (Markov, pers. comm.). Live specimens were collected 50 meters from the cave’s entrance, where the environmental conditions were characteristic for a cave. There was no light entering, air temperature 6.6° C, and that of the water 9.6° C with oxygen level of 9.0 mg/l. Living snails were found along the whole stretch of the stream up to the surfacing of the stream from a narrow cave whole, close to the cave’s end. At the cave’s middle parts there was a large mound of guano beneath a large bat colony, and close to the stream. At this area the oxygen in the stream dropped a little to 8.8 mg/l, the water temperature was similar, while the air warmed to 10.3° C. The only macro invertebrate animal species found to live with B. markovi were flat worms Planaria sp. which could be the only predator of the snails. Taking 117 at random 2x2 cm2 square samples (14.03.2009) from under stone surfaces in the stream, we collected a total of 16 individuals of B. markovi which showed a relative density of 0.14 individuals per 2 cm2 (min-max = 0-2 individuals).
Systems:Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): Main threats include organic and chemical pollution (domestic, agriculture) active at the cave entrance. There are occasional losses of individuals by cavers and other visitors of the cave when walking in the stream.

Conservation Actions [top]

Conservation Actions:

There are no species-specific conservation actions in place, although the habitat monitoring would be recommended, along with protection of the habitat.


Citation: Georgiev, D. 2010. Bythinella markovi. The IUCN Red List of Threatened Species 2010: e.T172039A6826846. . Downloaded on 20 January 2018.
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