|Scientific Name:||Orconectes sheltae Cooper & Cooper, 1997|
|Red List Category & Criteria:||Critically Endangered B2ab(iii) ver 3.1|
|Assessor(s):||Schuster, G.A., Taylor, C.A. & Cordeiro, J.|
|Reviewer(s):||Collen, B. & Richman, N.|
|Contributor(s):||Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Livingston, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G.|
Orconectes sheltae has been assessed as Critically Endangered under Criterion B2. This species has an area of occupancy (AOO) less than 1 km² and occurs in only one cave. This cave specialist is likely to be sensitive to habitat alterations. It is inferred that this species is experiencing declines in abundance, due to the reduction in nutrient availability from Gray Bat guano since the bats have abandoned the cave. Attempts have been made to encourage the bats to return, but so far these attempts have proved unsuccessful. A cave fence has been erected to reduce vandalism, which has been successful. The NSS is controlling the number of visitors to the cave, but still allowing school groups to visit, thus continuing to cause disturbance to this species' habitat. However, no attempts have been made to improve the water quality of the cave, by reducing insecticide run-off from nearby gardens. Monitoring of the population numbers is needed as the population is likely to be small and any single significant threat may result in extinction.
|Range Description:||This species is endemic to one cave, Shelta cave, in Madison County, Alabama, USA (Buhay 2006), where it co-occurs with O. australis and Camberis jonesi (Cooper and Cooper 1997). Within this cave, this species is found in a 283 m² subterranean lake, down a 762 m long passage (Cooper and Cooper 1997). The extent of occurrence of this species has been estimated to exceed 2,100 km², although the inferred area of occupancy (AOO) is thought to be less than 1 km².|
Native:United States (Alabama)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The species is known from 17 specimens, held in the Smithsonian Natural History Museum (holotype and the allotype) and the North Carolina State museum. Another 97 individuals were examined and released during a study between 1968 and 1975 (Cooper and Cooper 1997, Buhay and Crandall 2008).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||This species is found in a subterranean lake and passage, where it is dependent on external nutrients entering the cave, such as leaf litter. In addition, the guano of the Gray Bat Myotis grisescens provides nutrient input (Cooper and Cooper 1997).|
|Generation Length (years):||30|
|Major Threat(s):||This species is impacted by a variety of threats, namely land development, vandalism, cave abandonment by Gray Bats, insecticides and water level fluctuations. In the 1960s, there was extensive vandalism in the cave while the surrounding land was developed with residential housing (Cooper and Cooper 1997). In 1967, the cave was purchased by the National Speleological Society (NSS) which owns the entrances and controls access to the cave. The Headquarters of the NSS has been built above the cave (Mississippi State University 2003). In an attempt to curb vandalism, cave gates were built at the entrances to the caves in 1968, but these were not conducive to Gray Bat colonization. By 1970, the bats had abandoned the cave, reducing the amount of nutrients available for this species. Overall cave biodiversity has declined since the Gray Bats left the cave (Cooper and Cooper 1997). In 2002, a fence was erected 20 feet around the cave to encourage the bats to return, and to continue to deter vandalism (NSS 2003). Some water chemistry analysis has been conducted at the cave, which found high levels of the insecticide Heptachlor epoxide in 1989 presumably from surrounding residential gardens (Mississippi State University 2003). Additionally, this area of Alabama, due to geological circumstances, is prone to having high levels of radon gas. Levels in the cave were very high at 400 - 500 pCi/L, although the impact of this on this species is unknown. Finally, this species is sensitive to water level fluctuations, common at this site as a result of droughts. The NSS is controlling the number of visitors to the cave, but still allows school groups to visit, thus continuing to cause disturbance to this species suitable habitat (S. Adams, G. Schuster and C. Taylor, pers. comm. 2009).|
This species has been given a Global Heritage Status Rank of G1 by NatureServe (Taylor et al. 2007, NatureServe 2009) and assessed as 'endangered' by the American Fisheries Society (Taylor et al. 2007).
The cave within which this species is located, has been protected by the NSS since 1967. Protection measures include a cave fence surrounding the cave's entrances and the surrounding area. Buhay and Crandall (2008) assessed the species using IUCN criteria and recommended a Critical (CR) listing be imposed, owing to a decline in EOO, found at a single location, and an inferred decline in number of mature individuals.
Monitoring of the population trends is urgently needed.
|Citation:||Schuster, G.A., Taylor, C.A. & Cordeiro, J. 2010. Orconectes sheltae. The IUCN Red List of Threatened Species 2010: e.T153962A4569540.Downloaded on 23 September 2017.|
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