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Corynorhinus rafinesquii

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA CHIROPTERA VESPERTILIONIDAE

Scientific Name: Corynorhinus rafinesquii
Species Authority: (Lesson, 1827)
Common Name/s:
English Rafinesque's Big-eared Bat
Synonym/s:
Plecotus rafinesquii Lesson, 1827
Taxonomic Notes: This bat was referred to as Corynorhinus macrotis in older literature, and Corynorhinus townsendii was known as C. rafinesquii. Bogdanowicz et al. (1998) examined morphological and chromosomal variation and found that Corynorhinus is strongly supported as a distinct genus, with Plecotus limited to Palaearctic species. The mammal list by Simmons (2005) also accepted Corynorhinus as the appropriate genus for New World big-eared bats.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor/s: Arroyo-Cabrales, J. & Ticul Alvarez Castaneda, S.
Reviewer/s: Medellín, R. (Chiroptera Red List Authority) & Schipper, J. (Global Mammal Assessment Team)
Justification:
This species is listed as Least Concern in because of its wide distribution, presumed stable and due recuperation programs increase of population, occurrence in a number of protected areas, and because it is unlikely to be declining at nearly the rate required to qualify for listing in a threatened category.
History:
1996 Vulnerable

Geographic Range [top]

Range Description: The range extends from southern Virginia, West Virginia, Ohio (Handley 1991), Indiana, and Illinois south to Florida (primarily the panhandle and northern and central portions of the peninsula) and the Gulf of Mexico; west to Louisiana, Arkansas (known primarily from the Gulf Coastal Plain), eastern Oklahoma, and the eastern edge of Texas (Schmidly 2004) (Whitaker and Hamilton 1998; Lynch and Jones, in Wilson and Ruff 1999). Elevational range in the Great Smoky Mountains National Park extends to at least 2,400 feet.
Countries:
Native:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Population size is not known to exceed 10,000 mature individuals, but data are lacking for many areas. This bat never has been considered abundant. In general, it roosts in small numbers at scattered locations (e.g., in Alabama, the largest known colony includes only a few individuals). Population is thought to be 1,000-2,000 in each of Kentucky and South Carolina. This is one of the most common bats in the Great Smoky Mountains National Park; hibernation roosts include up to several hundred individuals (e.g., in 1993, two roosts included 454 and 699 bats); Harvey (1991) reported a hibernating colony of 570 individuals as well as smaller maternity roosts. In a cave in Kentucky, counts of hibernating C. rafinesquii ranged from 14-49, with summer colony size reaching a maximum of 118 bats (Hurst and Lacki 1999). In southern Mississippi, the number of bats present under occupied bridges ranged from 1 to 25 per bridge (Trousdale and Beckett 2004). In Florida, this bat is uncommon in the northern part of the state and rare in the south (Florida Bat Center, www.floridabats.org). In Georgia, it is widespread but rare (Georgia Wildlife Web). In much of the range thorough searches have not been completed and abundance is poorly known.

No range-wide statistics on trends are available, but four states (Georgia, West Virginia, South Carolina, and Tennessee) reported documented population declines, and populations in Indiana and Ohio probably have been extirpated. Four other states (Alabama, Arkansas, Illinois, and North Carolina) reported suspected declines. In summary, the species is known or suspected to be declining in more than half (10 out of 18) of the states within its range. In most other states, data are unavailable to determine trends.
Population Trend: Increasing

Habitat and Ecology [top]

Habitat and Ecology: The number of occurences is certainly greater than 100, but the number of known extant summer and winter roosting sites with large numbers of bats (> 100) is only 6 to 8 in any one year, and these sites are clustered in Kentucky and North Carolina. As of 2005, the species had been recorded from 18 counties in Tennessee (Tennessee Bat Working Group).

Several occurrences are known from state or national parks, including the largest known hibernating colony and some large (>100 individuals) maternity colonies in the Great Smoky Mountains National Park. Two large hibernating colonies in the Great Smoky Mountain National Park are partially protected, one with a gate and the other with fencing. Additional protected occurrences include (but are not limited to) the following. One protected colony occurs in Carter Cave, Kentucky. A colony also occurs in Natural Bridge State Park in Kentucky. Sites on USFS property are required under NEPA to be considered when evaluating effects of management practices. One large maternity colony is within Mammoth Caves National Park. Arkansas has gated several caves with Myotis sodalis colonies, and these may also be potential roost sites for Rafinesque's long-eared bats (Harvey 1992). Two maternity colonies in old buildings in Illinois have been protected, and the buildings repaired to extend their useful life (Gardner 1992).
This is a bat of forested regions. Hibernation in the north and in mountainous regions most often occurs in caves or similar sites; small caves are selected, and the bats stay near the entrance (often within 30 meters) and are thought to move about in winter (Handley 1959, Barbour and Davis 1969). Winter habitat in the south is poorly known, but usually this species is not found in caves during winter. In the Coastal Plain they are suspected to use hollow trees for cold weather and possibly winter roosts. In the southern portions of the range these bats often roost in buildings year round. Summer roosts often are in hollow trees, occasionally under loose bark, or in abandoned buildings in or near wooded areas. Nursery colonies are rare in caves, but are known to occur in Kentucky and Tennessee (Barbour and Davis 1969). A large nursery colony (87 adults in June of 1985) roosts in abandoned copper mines in Great Smoky Mountains National Park (Currie 1992).

In Louisiana, Gooding and Langford (2004) found that roost trees were hollow Nyssa aquatica with triangular-shaped basal openings, and all were located within a 5-hectare tupelo stand. In Mississippi, Trousdale and Beckett (2005) found that tree roosts were in hollow Nyssa spp. and Magnolia grandiflora. Most of the trees were still alive, relatively large, and were adjacent to streams or other bodies of water. Tree roosts were apparently rare within the study area, and C. rafinesquii showed roost fidelity to particular areas of forest. Six tree roosts were used by multiple individuals and several trees were reused within tracking sessions and among years.

In Louisiana, Lance et al. (2001) demonstrated that bridges, especially girder bridges, are important day-roost sites. Tagged bats in this study roosted under bridges 50% of the time and in black gum trees (Nyssa aquatica) 50% of the time. In Mississippi, small groups of females (mean of 5.6 adult females) used concrete bridges as maternity roosts; the bridges were much less used in fall and winter (Trousdale and Beckett 2004). It has been suggested that the species began using man-made structures in the coastal plain region only after large old hollow trees became scarce.

In Arkansas these bats are found in cisterns and wells rather than caves (Harvey 1992). In the mountains of South Carolina they roost in rock houses, abandoned gold mines, and hollow trees. In the coastal plain of North Carolina, they move into old buildings in the summer. They are known to use hollow trees as temporary night roosts between feeding bouts in the summer. In central Florida, a maternity roost was in an abandoned trailer that had been placed on a site in the early 1980s; it had been occupied for several years by the mid-1990s (Finn 1996).

Dilapidated buildings are inhabited more commonly than are intact occupied structures, and Clark (1987) reported that these bats roost in the darkest parts of such buildings. Others have reported that these bats choose more open and lighted daytime roosts than other kinds of bats (Handley 1959, Barbour and Davis 1969, Harvey 1992). Clark (1987) agreed that in caves and mines this species prefers areas receiving some natural light. The foraging habitat is primarily mature forest in both upland and lowland areas. In North Carolina and Virginia, foraging habitat for subspecies Macrotis is mature hardwood floodplain forest; sites along permanent water bodies, especially rivers, are preferred (Clark 1987). In the Upper Coastal Plain of South Carolina, where large contiguous tracts of mature bottomland hardwoods were common, most foraging activity of males nevertheless occurred in young pine stands; only 9% of foraging areas were in bottomland hardwoods (Menzel et al. 2001).
Systems: Terrestrial

Threats [top]

Major Threat(s): Much historically occupied habitat was lost with the clearing of swampland forests. Present threats include: forest destruction (significant in parts of coastal plain); hollow tree removal during certain forest management practices (widespread; noted in Mississippi as important); decreasing availability of abandoned buildings through razing and vandalism (serious threat in coastal plain); insecticide applications, at least in past; vandalism of caves and mines, and closing or blasting mines shut (England et al. 1992). There is considerable potential for loss and degradation of roosting and foraging habitats by commercial logging practices in preferred habitat (Schmidly 2004).

This species is very intolerant of disturbance (natural or human) and may abandon roost sites or hibernation sites if subjected to disturbance. Disturbance in winter may arouse bats and cause them to use up fat needed to survive the winter (Harvey 1992). Tendency to roost in cave entrances makes this bat especially vulnerable to disturbance. One roost site was abandoned after the surrounding area was logged.

Conservation Actions [top]

Conservation Actions: More accurate information is needed on distribution and status. Range-wide investigation, in light of reported declines, is justified. States where surveys have been directed only at caves, or where no bat surveys have been conducted in recent years, should be targeted first for searches, and searches must be targeted at this species in particular. Abandoned buildings should be searched as potential roost sites (Finn 1996).
Protect all colony sites with more than 10 bats present. Foraging habitat may be critical to species survival and should therefore be protected (protect mature floodplain and swamp forests; maintain large hollow tree component of such forests). Abandoned-building roost sites should be protected or, if need be, replaced with a potential alternate roost area on the site (Finn 1996).
More accurate information is needed on general biology, foraging habitat, foraging behavior, and the importance of mature forests, hollow trees for roosts, and small maternity colonies.
Citation: Arroyo-Cabrales, J. & Ticul Alvarez Castaneda, S. 2008. Corynorhinus rafinesquii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 19 April 2014.
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