Idionycteris phyllotis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Chiroptera Vespertilionidae

Scientific Name: Idionycteris phyllotis (G.M. Allen, 1916)
Common Name(s):
English Allen's Big-eared Bat
Taxonomic Notes: This species formerly included in the genus Plecotus Simmons (2005) treated Idionycteris phyllotis and Euderma maculatum as generically distinct.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2017
Date Assessed: 2016-08-26
Assessor(s): Arroyo-Cabrales, J. & Álvarez-Castañeda, S.T.
Reviewer(s): Solari, S.
This species is listed as Least Concern in because of its wide distribution, presumed large 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.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species occurs from Distrito Federal and Michoacan (Mexico) to south Utah and south Nevada (USA) (Simmons 2005). The range encompasses the southwestern United States and part of Mexico, from southern Utah and southern Nevada south through Arizona (northwestern, central, southeastern; Hoffmeister 1986) and New Mexico (Mogollon Plateau and western Soccoro County in the San Mateo and Magdalena mountains (Frey 2004) to Distrito Federal and Michoacan in southern central Mexico (Simmons, 2005), including the Sierra Madre Occidental, Sierra Madre Oriental, and Sierra Volcanica Transversal. The range closely approaches California and Colorado, but as of 2005 no records were available for those states. The winter range is not known. The elevational range extends from 403 to 3,225 meters, with most records at 1,100-2,500 meters. Subspecies hualapaiensis: southern Nevada, southern Utah, and northern Arizona (Mohave County and Coconino County north of the Grand Canyon); subspecies phyllotis: remainder of range (Tumlison and Douglas 1992).
Countries occurrence:
Mexico; United States (Arizona, California, Nevada, New Mexico, Utah)
Additional data:
Lower elevation limit (metres):403
Upper elevation limit (metres):3225
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The species is uncommon in USA (Wilson and Ruff 1999), where it is represented by several dozen occurrences or subpopulations. Occurrence information is not available for the bulk of the range in Mexico. In Mexico these are considered uncommon (Ceballos and Oliva 2005).

Total adult population size is unknown but presumably exceeds 10,000. Up to 100 individuals per roost have been observed in six roosts in the Coconino National Forest, Arizona (Mammal Diversity Review Notes 1996).

Population trends are not definitely known, but extent of occurrence, area of occupancy, number of subpopulations, and population size probably have not declined substantially compared to the historical situation. Barbour and Davis (1969) and Hoffmeister (1986) pointed to the paucity of pre-1955 records for Arizona and discussed the possibility that this species has only recently expanded its range to Arizona, Nevada, Utah, and New Mexico. Hoffmeister (1986) found no factor (e.g., habitat change) that might account for this possible change. Population trends are unknown in Utah and Nevada (G. Oliver and C. Carreno pers. comm. 1998). Possibly stable in Arizona (S. Schwartz pers. comm. 1998).
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:The biology of this species is poorly known. It occurs in a variety of wooded habitats including especially ponderosa pine forest, pinyon-juniper woodland, riparian woodland, encinal (oak woodland), pine-oak woodland, and fir forest. Others come from more arid habitats, including desert shrub, mesquite grassland with scattered oaks, xeric scrub, and tropical deciduous forest. The species is a highly adapted insect predator using a sophisticated combination of sonar signals and flight maneuvers to forage for and intercept its nocturnal prey. It feeds on small moths; other known prey include soldier beetles, dung beetles, leaf beetles, roaches, and flying ants (Wilson and Ruff 1999).
Habitat is primarily mountainous wooded areas (e.g., ponderosa pine, pinyon-juniper, Mexican woodland, oak brsuh) but also includes riparian (e.g., cottonwood) woodland and ranges from Mohave desert scrub of low desert ranges to white fir forest (Hoffmeister 1986). Typically this bat is found near rocks: cliffs, boulders, lava flows, etc., and it is frequently netted along streams or over ponds. Maternity colonies of 30 to 150 individuals have been found in mine shafts, boulder piles, sandstone crevices, lava beds, and beneath the loose bark of large ponderosa pine snags (Bat Conservation International, Western Bat Working Group, Czaplewski 1983, Rabe et al. 1998, Adams 2003).

Threats [top]

Major Threat(s): Extent of occurrence, area of occupancy, number of subpopulations, and population size apparently have declined but probably at a rate of less than 10% over 10 years or three generations. Threats include recreational entry into occupied caves/mines, active mining in occupied tunnels, vandalism or closure of abandoned mines used as maternity roosts, and timber management practices that reduce the availability of large pine snags for roosting. The Western Bat Working Group categorized the threat as "High" throughout the Rocky Mountain region (Adams 2003). The Arizona and Nevada natural heritage programs considered the degree of threat to be moderate (Sabra Schwartz and Carrie Carreno pers. comm., 1998). Lack of adequate information for Mexican populations prevents range-wide assessment of the scope of threat. An important mine roost was destroyed by relocation of a nearby highway (Adams 2003). Maternity colonies are easily disturbed, often resulting in abandonment (Arizona Game and Fish Department 1997). Limited data suggest that this bat may abandon mines that have been gated to prevent recreational entry, even if the gates are permeable to other bat species (Western Bat Working Group).

Conservation Actions [top]

Conservation Actions: At least four protected occurrences exist in Utah: Canyonlands National Park, Capitol Reef National Park, Glen Canyon National Recreation Area, and Natural Bridges National Monument (George Oliver pers. comm., 1998), and at least a few additional protected occurrences are in Arizona (e.g., Grand Canyon National Park) and New Mexico. Occurrences in several national forests and in national wildlife refuges do not necessarily result in much protection for this species. Increased efforts are needed to improve our knowledge of the distribution and abundance of this species throughout its range.Most aspects of the ecology of this species need further study.

Citation: Arroyo-Cabrales, J. & Álvarez-Castañeda, S.T. 2017. Idionycteris phyllotis. The IUCN Red List of Threatened Species 2017: e.T10790A21990019. . Downloaded on 17 October 2017.
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