Myotis ciliolabrum

Myotis ciliolabrum formerly was included in M. leibii (and earlier in M. subulatus) but was recognized as a distinct species by van Zyll de Jong (1984). Analysis by Ammerman et al. (2016) of nuclear amplified fragment length polymorphism (AFLP) markers recovered distinct genetic lineages or clusters that corresponded to the recognized species defined by morphology, M. californicus, M. ciliolabrum, and M. leibii and did not support recognition M. melanorhinus as a distinct species or as a subspecies of M. ciliolabrum.

Two subspecies have been recognized, based on color of pelage: M. c. ciliolabrum and M. c. melanorhinus (Holloway and Barclay 2001). Myotis melanorhinus was recognized at the species level by Simmons (in Wilson and Reeder 2005), citing support by van Zyll de Jong (1984). However, according to Ammerman et al. (2016), this was an "unfortunate mistaken interpretation of van Zyll de Jong (1984) that has been perpetuated by recent authors (such as Medellin et al., 2008; Kays and Wilson, 2009; Harvey et al., 2011)."

Widespread in western North America; large number of collection/observation sites and locations (as defined by IUCN); wide range of habitats and roost sites (including human-made structures), though hibernation sites are mainly in caves and abandoned mines, some of which are vulnerable to disturbance or unfavorable alteration; locally fairly common; no evidence of significant decline; apparently not very threatened; many protected occurrences. Taxonomic issues need to be resolved.

Range includes western North America from southern Saskatchewan, southern Alberta, and southern British Columbia south through the western United States (not including coastal areas north of southern California, east to the Dakotas, Nebraska, Kansas, Oklahoma, and Texas) and into central Mexico (Holloway and Barclay 2001, Western Bat Working Group 1998, Bat Conservation International 1998, Adams 2003, Reid 2006). Winter range is the same as the summer range in at least some regions, but winter status is unknown in some areas (e.g., Texas, Ammerman et al. 2012). Elevational range extends to at least 2,743 meters in Colorado (Adams 2003), to 3,300 meters in some areas (Hayes and Wiles 2013).

The number of distinct occurrences has not been determined using standardized/meaningful criteria, but the species is represented by a large number of collection/observation sites and locations (as defined by IUCN). Hoffmeister (1986) and Arizona Game and Fish Department (http://www.azgfd.gov/w_c/edits/images/Myotcili_001.gif) mapped a few dozen collection sites or occurrences in Arizona. Verts and Carraway (1998) mapped a few dozen collection sites in Oregon. Several dozen locations have been recently recorded in Montana (http://fieldguide.mt.gov/detail_AMACC01140.aspx).

Overall, no major threats are known. Populations tend to be widely dispersed in small groups among many sites and so are not vulnerable to significant declines from localized events.

Locally, threats include wanton killing and human disturbance of hibernacula. On two occasions bats that had been killed were observed in a South Dakota cave (Tigner and Aney 1993). Special precautions should be taken when mine and cave surveys are conducted during breeding periods and winter hibernation. Disturbance of breeding colonies can cause young to lose their grasp and fall to their death. Disturbance during hibernation can cause bats to use up stored fat reserves and starve to death.

This species may be affected by the closure of abandoned mines without adequate surveys, and by recreational caving (Garcia et al. 1995, Bogan et al. 2005). Tuttle and Taylor (1994) found that populations relied heavily on mines for hibernation, even though a large proportion of the populations were normally not found in any one mine. In Utah, the Abandoned Mine Reclamation Program of the Utah Division of Oil, Gas and Mining carries out closures of abandoned mines for human safety; however, careful surveys for bats in mines scheduled for possible closure are conducted during both warm and cold seasons to ensure that abandoned mines that are used by bats are not closed but rather are gated (M. R. Mesch, pers. comm., cited by Oliver 2000).

In Alberta, the species is vulnerable to loss of foraging habitat (riparian cottonwood stands), as well as habitat loss by direct flooding caused by dams on the lower reaches of rivers in southern Alberta (Alberta Sustainable Resource Development and Alberta Conservation Alliance 2008).

Loss or degradation of shrub-steppe for agriculture, grazing, and other uses has reduced the amount of foraging habitat and likely altered prey availability (Hayes and Wiles 2013).

This species is not known to incur significant mortality from turbines at wind energy facilities (Arnett and Baerwald 2013).

As of mid-2014, this species was not known to be affected by white-nose syndrome.

Contaminant/pesticide poisoning is a possible threat (Bogan et al. 2005), either through direct poisoning or by decreasing the prey base (Hayes and Wiles (2013). However, the population impact of these factors is unknown.

Ongoing climate change may affect this species, but the future impacts of associated drought, habitat changes, and other factors are highly uncertain.