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Aphaostracon pycnus 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Littorinimorpha Hydrobiidae

Scientific Name: Aphaostracon pycnus Thompson, 1968
Common Name(s):
English Dense Hydrobe
Synonym(s):
Aphaostracon pycnum Thompson, 1968
Taxonomic Notes: Thompson (1968) described this species as Aphaostracon pycnus. This was later changed (possibly as a gender correction) by Turgeon et al. (1998) to A. pycnum. However, according to the ICZN (1999) the original spelling should stand as there has not been a genuine change in rank or combination (e.g., from subspecies to species or a genus shift); therefore A. pycnus remains the correct spelling (NatureServe 2009).

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-03-14
Assessor(s): Cordeiro, J. & Perez, K.
Reviewer(s): Bohm, M., Collen, B. & Seddon, M.
Contributor(s): Dyer, E., Soulsby, A.-M., Whitton, F., Kasthala, G., McGuinness, S., Milligan, HT, De Silva, R., Herdson, R., Thorley, J., McMillan, K., Collins, A., Offord, S., Duncan, C. & Richman, N.
Justification:
Aphaostracon pycnus has been assessed as Vulnerable under criterion D2, as it has a very restricted distribution with an estimated area of occupancy of less than 20 km2. While there are currently no documented declines with the speices occurring within a Florida National Forest, potential future threats are likely to affect the population significantly enough to cause severe and rapid declines over a timeframe of 10 to 15 years, thus threatening the survival of this species. The most likely threats are an increased frequency of drought events impacting the recharge of the groundwaters feeding the system, change in National Forest legislation with reduced protection to the location and nutrient loading from agricultural and urban runoff. While the species was considered for federal government listing, this was never put in place. However, the species would benefit from appropriate protection which buffers against potential future declines.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to Alexander Spring Run, Ocala National Forest, Lake County in Florida (Thompson 2004, NatureServe 2009). Shelton (2005) states that this species also occurs in Silver Glen Springs, around 20 km north of Alexander Springs. This record should be verified as it may constitute an important, and previously unknown, population of this species.
Countries occurrence:
Native:
United States (Florida)
Additional data:
Estimated area of occupancy (AOO) - km2:<20km2
Number of Locations:1-2
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is known only from one locality, and it is not known whether this represents a single or several populations (NatureServe 2009). Recent claims of a second location north of Alexander Springs require verification.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species is restricted to forest springs.
Systems:Freshwater

Use and Trade [top]

Use and Trade: This species is not utilised.

Threats [top]

Major Threat(s): There are no current threats to this species. However, plausible future threats to this species are an increased frequency of drought events impacting the recharge of the groundwaters feeding the system, change in National Forest legislation with reduced protection to the location and nutrient loading from agricultural and urban runoff. Each of these has the potential to rapidly lead to significant declines in the population, ultimately leading to extinction of the species, within 10 to 15 years unless actions are taken to safeguard the species.

Other potential future threats might stem from tourism as the species occurs inside a National Forest. The US Forest Service website states that Alexander Springs is a "popular recreation area" (US Forest Service 2010). Melhop and Vaughn (1994) reported that swimmers temporarily displaced a related species, Aphaostracon monas, from a spring in Florida, although the snails repopulated the spring following the swimming season.

Vehicle pollution from Route 445, adjacent to Alexander Springs, may also be a threat. This species is likely to be vulnerable to small changes in water quality to its currently pristine habitat, similar to other hydrobiids (Melhop and Vaughn 1994).

Conservation Actions [top]

Conservation Actions: This species is listed as Vulnerable on the IUCN Red List (version 2.3 1996) under criterion D2 (very small or restricted population) (IUCN 2009). It has a Global Heritage Status of G1 (Critically Imperilled) (NatureServe 2009). The one known locality of this species is inside a National Forest (Ocala National Forest). The level of protection this awards to snails and freshwater habitats in general is unknown (NatureServe 2009).

Further work is needed to verify the second population recorded by Shelton (2005) at Silver Glen Springs, as this could be important for the long-term viability of this species. In addition, research is recommended to determine the status of the stream and surrounding habitat (e.g., riparian, forest) in which this species is found. The species and its habitat should also be incoporated into the National Forest management plans, and considered for State/Federal listing (NatureServe 2009). The US government considered listing this species in 1984, but it was never listed.

Classifications [top]

5. Wetlands (inland) -> 5.9. Wetlands (inland) - Freshwater Springs and Oases
suitability:Suitable  major importance:Yes
1. Land/water protection -> 1.2. Resource & habitat protection
2. Land/water management -> 2.1. Site/area management
5. Law & policy -> 5.1. Legislation -> 5.1.2. National level
5. Law & policy -> 5.1. Legislation -> 5.1.3. Sub-national level

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
11. Climate change & severe weather -> 11.2. Droughts
♦ timing:Future ♦ scope:Whole (>90%) ♦ severity:Rapid Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

6. Human intrusions & disturbance -> 6.1. Recreational activities
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 2. Species Stresses -> 2.2. Species disturbance

9. Pollution -> 9.1. Domestic & urban waste water -> 9.1.2. Run-off
♦ timing:Future ♦ scope:Whole (>90%) ♦ severity:Rapid Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

9. Pollution -> 9.3. Agricultural & forestry effluents -> 9.3.1. Nutrient loads
♦ timing:Future ♦ scope:Whole (>90%) ♦ severity:Rapid Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

9. Pollution -> 9.5. Air-borne pollutants -> 9.5.4. Type Unknown/Unrecorded
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.2. Population size, distribution & trends
3. Monitoring -> 3.4. Habitat trends

Bibliography [top]

ICZN International Code of Zoological Nomenclature. 1999. International Commission on Zoological Nomenclature. International Trust for Zoological Nomenclature, London.

IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).

IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012).

Melhop, P. and Vaughn, C. C. 1994. Threats to and sustainability of ecosystems for freshwater mollusks. In: W. covington and L. F Dehand (eds), Sustainable Ecological Systems: Implementing an ecological approach to land management. U.S Forest Service, Rocky Mountain Range and Forest Experimental Station, Fort Collins, Colorado.

NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. Internet

Shelton, D. N. 2005. The rare and endemic snails of selected springs within the St. Johns river water management district. Alabama Malacological Research Center.

Thompson, F. G. 1968. The aquatic snails of the family Hydrobiidae of peninsular Florida. University Florida Press, Gainesville.

Thompson, F.G. 2004. An Identification manual for the freshwater snails of Florida. Gainesville, Florida Available at: http://www.flmnh.ufl.edu/malacology/fl-snail/snails1.htm.

Turgeon, D.D., Quinn, Jr. J.F., Bogan, A.E., Coan, E.V., Hochberg, F.G., Lyons, W.G., Mikkelsen P.M., Neves, R.J., Roper, C.F.E., Rosenberg, G., Roth, B., Scheltema, A., Thompson, F.G., Vecchione, M. and Williams, J.D. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada. American Fisheries Society, Mollusks.

US Forest Service. 2010. Ocala National Forest, US Forest Service, Southern region.


Citation: Cordeiro, J. & Perez, K. 2012. Aphaostracon pycnus. The IUCN Red List of Threatened Species 2012: e.T1858A1780266. . Downloaded on 16 August 2018.
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