Endangered and Threatened Wildlife and Plants; Threatened Species Status for the Northern Long-Eared Bat With 4(d) Rule

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R5-ES-2011-0024; 4500030113]

RIN 1018-AY98

Endangered and Threatened Wildlife and Plants; Threatened Species Status for the Northern Long-Eared Bat With 4(d) Rule

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule, and interim rule with request for comments.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), determine threatened species status under the Endangered Species Act of 1973 (Act), as amended, for the northern long-eared bat (

Myotis septentrionalis

), a bat species that occurs in 37 States, the District of Columbia, and 13 Canadian Provinces. The effect of this final rule will be to add the northern long-eared bat to the List of Endangered and Threatened Wildlife.

We are also establishing an interim rule under the authority of section 4(d) of the Act that provides measures that are necessary and advisable to provide for the conservation of the northern long-eared bat. We are seeking public comments on this interim rule, and we will publish either an affirmation of the interim rule or a final rule amending the interim rule after we consider all comments we receive. If you previously submitted comments or information on the proposed 4(d) rule we published on January 16, 2015, please do not resubmit them. We have incorporated them into the public record, and we will fully consider them in our final determination on the 4(d) rule.

DATES:

Effective dates:

The final rule amending 50 CFR 17.11 and the interim rule amending 50 CFR 17.40 are both effective May 4, 2015.

Comments on the interim rule amending 50 CFR 17.40:

We will accept comments on the interim rule amending 50 CFR 17.40 received or postmarked on or before July 1, 2015. Comments submitted electronically using the Federal eRulemaking Portal (see

ADDRESSES

, below) must be received by 11:59 p.m. Eastern Time on the closing date.

ADDRESSES:

Document availability:

The final listing rule is available on the Internet at

http://www.regulations.gov

under Docket No. FWS-R5-ES-2011-0024 and at

http://www.fws.gov/midwest/Endangered.

Comments and materials we received, as well as supporting documentation we used in preparing the final listing rule, are available for public inspection at

http://www.regulations.gov,

and by appointment, during normal business hours at: U.S. Fish and Wildlife Service, Twin Cities Ecological Services Office, 4101 American Blvd. East, Bloomington, MN 55425; telephone (612) 725-3548, ext. 2201; or facsimile (612) 725-3609.

Comments on the interim rule amending 50 CFR 17.40:

You may submit comments on the interim rule amending 50 CFR 17.40 by one of the following methods:

(1) Electronically: Go to the Federal eRulemaking Portal:

http://www.regulations.gov.

In the Search box, enter FWS-R5-ES-2011-0024, which is the docket number for this rulemaking. Then click on the Search button. Please ensure that you have located the correct document before submitting your comments. You may submit a comment by clicking on “Comment Now!”

(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R5-ES-2011-0024; Division of Policy, Performance, and Management Programs; U.S. Fish and Wildlife Service, MS: BPHC; 5275 Leesburg Pike, Falls Church, VA 22041-3803.

We request that you send comments only by one of the methods described above. We will post all comments on

http://www.regulations.gov.

This generally means that we will post any personal information you provide us (see the Public Comments Solicited on the Interim 4(d) Rule section, below, for more information).

FOR FURTHER INFORMATION CONTACT:

Lisa Mandell, Deputy Field Supervisor, U.S. Fish and Wildlife Service, Twin Cities Ecological Services Field Office, 4101 American Blvd. East, Bloomington, MN 55425; telephone (612) 725-3548, ext. 2201; or facsimile (612) 725-3609. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

Final Listing Rule

Why we need to publish a rule: Under the Endangered Species Act, a species may warrant protection through listing if it is endangered or threatened throughout all or a significant portion of its range. Listing a species as an endangered or threatened species can only be completed by issuing a rule. This rule will finalize the listing of the northern long-eared bat (

Myotis septentrionalis

) as a threatened species.

The basis for our action: Under the Endangered Species Act, we can determine that a species is an endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that white-nose syndrome is the predominant threat to the species.

Peer review and public comment:

We sought comments from independent specialists to ensure that our designation is based on scientifically sound data, assumptions, and analyses. We invited these peer reviewers to comment on our listing proposal. We also considered all comments and information we received during the comment periods.

Interim 4(d) Rule

The need for the regulatory action and how the action will meet that need: Consistent with section 4(d) of the Act, this interim 4(d) rule provides measures that are tailored to our current understanding of the conservation needs of the northern long-eared bat.

Statement of legal authority for the regulatory action: Under section 4(d) of the Act, the Secretary of the Interior has discretion to issue such regulations as she deems necessary and advisable to provide for the conservation of the species. The Secretary also has the discretion to prohibit by regulation with respect to a threatened species, any act prohibited by section 9(a)(1) of the Act.

Summary of the major provisions of the regulatory action: The interim species-specific 4(d) rule prohibits purposeful take of northern long-eared bats throughout the species' range, except in instances of removal of northern long-eared bats from human structures and authorized capture and handling of northern long-eared bat by individuals permitted to conduct these same activities for other bats (for a period of 1 year after the effective date of the interim 4(d) rule).

In areas not yet affected by white nose syndrome (WNS), a disease currently affecting many U.S. bat populations, all incidental take resulting from any otherwise lawful activity will be excepted from prohibition.

In areas currently known to be affected by WNS, all incidental take prohibitions apply, except that take

attributable to forest management practices, maintenance and limited expansion of transportation and utility rights-of-way, prairie habitat management, and limited tree removal projects shall be excepted from the take prohibition, provided these activities protect known maternity roosts and hibernacula. Further, removal of hazardous trees for the protection of human life or property shall be excepted from the take prohibition.

Previous Federal Action

Please refer to the proposed listing rule for the northern long-eared bat (78 FR 61046; October 2, 2013) for a detailed description of previous Federal actions concerning this species. On October 2, 2013, we published in the

Federal Register

(78 FR 61046) a proposed rule to list the northern long-eared bat as an endangered species under the Act. The proposed rule had a 60-day comment period, ending on December 2, 2013. On December 2, 2013, we extended this comment period through January 2, 2014 (78 FR 72058). On June 30, 2014, we announced a 6-month extension of the final determination on the proposed listing rule for northern long-eared bat, and we reopened the public comment period on the proposed rule for 60 days, ending August 29, 2014 (79 FR 36698). On November 18, 2014, we again reopened the comment period on the proposed listing for an additional 30 days, ending December 18, 2014 (79 FR 68657). During the comment period we received one request for a public hearing, which was held in Sundance, Wyoming, on December 2, 2014. On January 16, 2015, we published a proposed rule to create a species-specific rule under section 4(d) of the Act (a “4(d) rule”) that would provide measures that are necessary and advisable to provide for the conservation of the northern long-eared bat, if it were to be listed as a threatened species (80 FR 2371). At that time, we also reopened the public comment period on the October 2, 2013, proposed listing rule; we accepted public comments on both proposals for 60 days, ending March 17, 2015.

Background

Taxonomy and Species Description

The northern long-eared bat belongs to the order

Chiroptera,

suborder

Microchiroptera,

family

Vespertilionidae,

subfamily

Vespertilioninae,

genus

Myotis,

and subgenus

Myotis

(Caceres and Barclay 2000, p. 1). The northern long-eared bat was considered a subspecies of Keen's long-eared myotis (

Myotis keenii

) (Fitch and Schump 1979, p. 1), but was recognized as a distinct species by van Zyll de Jong in 1979 (1979, p. 993), based on geographic separation and difference in morphology (as cited in Caceres and Pybus 1997 p. 1; Caceres and Barclay 2000, p. 1; Nagorsen and Brigham 1993, p. 87; Whitaker and Hamilton 1998, p. 99; Whitaker and Mumford 2009, p. 207; Simmons 2005, p. 516). The northern long-eared bat is currently considered a monotypic species, with no subspecies described for this species (Caceres and Barclay 2000, p. 1; Nagorsen and Brigham 1993, p. 90; Whitaker and Mumford 2009, p. 214; van Zyll de Jong 1985, p. 94). Reynolds (2013, pers. comm.) stated that there have been very few genetic studies on this species; however, data collected in Ohio suggest relatively low levels of genetic differentiation across that State (Arnold 2007, p. 157). In addition, Johnson

et al.

(2014, upaginated) assessed nuclear genetic diversity at one site in New York and several sites in West Virginia, and found little evidence of population structure in northern long-eared bats at any scale. This species has been recognized by different common names, such as: Keen's bat (Whitaker and Hamilton 1998, p. 99), northern myotis (Nagorsen and Brigham 1993, p. 87; Whitaker and Mumford 2009, p. 207), and the northern bat (Foster and Kurta 1999, p. 660). For the purposes of this finding, we refer to this species as the northern long-eared bat, and recognize it as a listable entity under the Act.

A medium-sized bat species, the northern long-eared bat's adult body weight averages 5 to 8 grams (g) (0.2 to 0.3 ounces), with females tending to be slightly larger than males (Caceres and Pybus 1997, p. 3). Average body length ranges from 77 to 95 millimeters (mm) (3.0 to 3.7 inches (in)), tail length between 35 and 42 mm (1.3 to 1.6 in), forearm length between 34 and 38 mm (1.3 to 1.5 in), and wingspread between 228 and 258 mm (8.9 to 10.2 in) (Caceres and Barclay 2000, p. 1; Barbour and Davis 1969, p. 76). Pelage (fur) colors include medium to dark brown on its back; dark brown, but not black, ears and wing membranes; and tawny to pale-brown fur on the ventral side (Nagorsen and Brigham 1993, p. 87; Whitaker and Mumford 2009, p. 207). As indicated by its common name, the northern long-eared bat is distinguished from other

Myotis

species by its relatively long ears (average 17 mm (0.7 in); Whitaker and Mumford 2009, p. 207) that, when laid forward, extend beyond the nose up to 5 mm (0.2 in; Caceres and Barclay 2000, p. 1). The tragus (projection of skin in front of the external ear) is long (average 9 mm (0.4 in); Whitaker and Mumford 2009, p. 207), pointed, and symmetrical (Nagorsen and Brigham 1993, p. 87; Whitaker and Mumford 2009, p. 207). There is an occasional tendency for the northern long-eared bat to exhibit a slight keel on the calcar (spur of cartilage arising from inner side of ankle; Nagorsen and Brigham 1993, p. 87). This can add some uncertainty in distinguishing northern long-eared bats from other sympatric

Myotis

species (Lacki 2013, pers. comm.). Within its range, the northern long-eared bat can be confused with the little brown bat (

Myotis lucifugus

) or the western long-eared myotis (

Myotis evotis

). The northern long-eared bat can be distinguished from the little brown bat by its longer ears, tapered and symmetrical tragus, slightly longer tail, and less glossy pelage (Caceres and Barclay 2000, p. 1; Kurta 2013, pers. comm.). The northern long-eared bat can be distinguished from the western long-eared myotis by its darker pelage and paler membranes (Caceres and Barclay 2000, p. 1).

Distribution and Relative Abundance

The northern long-eared bat ranges across much of the eastern and north-central United States, and all Canadian provinces west to the southern Yukon Territory and eastern British Columbia (Nagorsen and Brigham 1993, p. 89; Caceres and Pybus 1997, p. 1; Environment Yukon 2011, p. 10) (see Figure 1, below). In the United States, the species' range reaches from Maine west to Montana, south to eastern Kansas, eastern Oklahoma, Arkansas, and east to South Carolina (Whitaker and Hamilton 1998, p. 99; Caceres and Barclay 2000, p. 2; Simmons 2005, p. 516; Amelon and Burhans 2006, pp. 71-72). The species' range includes all or portions of the following 37 States and the District of Columbia: Alabama, Arkansas, Connecticut, Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, West Virginia, Wisconsin, and Wyoming.

The October 2, 2013, proposed listing rule included Florida within the range of the northern long-eared bat; however, since that time we have learned that the species was known from only a single historical winter (1954) record in

Jackson County, Florida, and all other historical and recent surveys at this cave and 12 other caves (all in Jackson County) since this record was observed have not found the northern long-eared bat. Further, there are no known summer records for the State (Florida Fish and Wildlife Conservation Commission 2013, in litt.). Historically, the species has been most frequently observed in the northeastern United States and in the Canadian Provinces of Quebec and Ontario, with sightings increasing during swarming and hibernation periods (Caceres and Barclay 2000, p. 2). Much of the available data on northern long-eared bats are from winter surveys, although they are typically observed in low numbers because of their preference for inconspicuous roosts (Caceres and Pybus 1997, p. 2) (for more information on use of hibernacula, see

Biology,

below). More than 1,100 northern long-eared bat hibernacula have been identified throughout the species' range in the United States, although many hibernacula contain only a few (1 to 3) individuals (Whitaker and Hamilton 1998, p. 100). Known hibernacula (sites with one or more winter records of northern long-eared bats) include: Alabama (2), Arkansas (41), Connecticut (8), Delaware (2), Georgia (3), Illinois (21), Indiana (25), Kentucky (119), Maine (3), Maryland (8), Massachusetts (7), Michigan (103), Minnesota (11), Missouri (more than 269), Nebraska (2), New Hampshire (11), New Jersey (7), New York (90), North Carolina (22), Oklahoma (9), Ohio (7), Pennsylvania (112), South Carolina, (2), South Dakota (21), Tennessee (58), Vermont (16), Virginia (8), West Virginia (104), and Wisconsin (67). Northern long-eared bats are documented in hibernacula in 29 of the 37 States in the species' range. Other States within the species' range have no known hibernacula (due to no suitable hibernacula present, lack of survey effort, or existence of unknown retreats).

For purposes of organization, the U.S. portion of the northern long-eared bat's range is discussed below in four parts: eastern range, midwest range, southern range, and western range. In these sections, we have identified the species' historical status, in addition to its current status within each State. For those States where white-nose syndrome (WNS) has been detected (see Table 1), we have assessed the impact the disease has had on the northern long-eared bat's distribution and relative abundance to date. For a discussion on anticipated spread of WNS to currently unaffected States, see “White-nose Syndrome” and “Effects of White-nose Syndrome on the Northern Long-eared Bat” under the

Factor C

discussion.

BILLING CODE 4310-55-P

ER02AP15.003

BILLING CODE 4310-55-C

Eastern Range

For purposes of organization in this rule, the eastern geographic area includes the following States and the District of Columbia: Delaware, Connecticut, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, Pennsylvania, Vermont, Virginia, West Virginia, New York, and Rhode Island. Historically, the northern long-eared bat was widely distributed in the eastern part of its range (Caceres and Barclay 2000, p. 2). Prior to documentation of WNS, northern long-eared bats were consistently caught during summer mist-net surveys and detected during acoustic surveys in the eastern United States (Service 2014, unpublished data). Northern long-eared bats continue to be distributed across much of the historical range, but there are many gaps within the range where bats are no longer detected or captured, and in other areas, their occurrence is sparse. Similar to summer distribution, northern long-eared bats were known to occur in many hibernacula throughout the East. Since WNS has been

documented, multiple hibernacula now have zero reported northern long-eared bats. Frick

et al.

(2015, p. 6) documented the local extinction of northern long-eared bats from 69 percent of sites included in their analyses (468 sites where WNS has been present for at least 4 years in Vermont, New York, Pennsylvania, Maryland, West Virginia, and Virginia).

In Delaware, the species is rare, but has been found at two hibernacula within the State during winter or fall swarming periods. Summer mist-net surveys have documented 14 individuals all from New Castle County, and there is also a historical record from this county in 1974 (Niederriter 2012, pers. comm.; Delaware Division of Fish and Wildlife 2014, in litt.). WNS was confirmed in the State in the winter of 2009-2010, and WNS was confirmed in Delaware in the two northern long-eared bat hibernacula during the winters of 2011-2012 and 2012-2013 (Delaware Division of Fish and Wildlife 2014, in litt.). Mortality of northern long-eared bats due to WNS has been documented at both of these hibernacula during winter surveys.

In Connecticut, the northern long-eared bat was historically one of the most commonly encountered bats in the State, and was documented Statewide (Dickson 2011, pers. comm.). WNS was first confirmed in Connecticut in the winter of 2008-2009. Prior to WNS detection in Connecticut, northern long-eared bats were found in large numbers (

e.g.,

often greater than 400 and up to 1,000 individuals) in hibernacula; however, no northern long-eared bats were found in any of the eight known hibernacula in the State (where the species was found prior to WNS) in 2012 or 2013 surveys (Service 2015, unpublished data).

In Maine, three bat hibernacula are known, and northern long-eared bats have been observed in all of these sites. The species has also been found in the summer in Acadia National Park (DePue 2012, unpublished data), where northern long-eared bats were fairly common in 2009-2010 (242 northern long-eared bats captured, comprising 27 percent of the total captures for the areas surveyed) (National Park Service (NPS) 2010, unpublished data). Recent findings from Acadia National Park show a precipitous decline in the northern long-eared bat population in less than 4 years, based on mist-net surveys conducted 2008-2014 (NPS 2014, in litt.). WNS was first confirmed in the State in the winter of 2010-2011. Prior to WNS, the northern long-eared bat was found in numbers greater than 100 at two of the three regularly surveyed hibernacula; however, in 2013, only one northern long-eared bat was found during surveys conducted at all three of the State's primary hibernacula (Maine Department of Inland Fisheries and Wildlife (MDIFW) 2013, in litt.). In addition, the northern long-eared bat was infrequently found in summer acoustic surveys conducted in the State in 2013, which contrasts with widespread, frequent acoustic detections of

Myotis

species and mist net captures of northern long-eared bats prior to WNS impact (MDIFW 2015, in litt.).

In Maryland, there are eight known hibernacula for the northern long-eared bat, three of which are railroad tunnels (Maryland Department of Natural Resources (MD DNR) 2014, unpublished data). WNS was first confirmed in Maryland in the winter of 2009-2010. In all five of the known caves or mines in the State, the species is thought to be extirpated due to WNS (MD DNR 2014, unpublished data). It is unknown if the species is extirpated from the known railroad tunnel hibernacula in the State, primarily because the majority of bats in these hibernacula are not visible or accessible during winter hibernacula surveys; however, no northern long-eared bats have been observed in accessible areas in these tunnel hibernacula during recent winter surveys (MD DNR 2014, unpublished data). Acoustic surveys conducted since 2010 (pre- and post-WNS) in the western portion of Maryland have also demonstrated northern long-eared bat declines due to WNS (MD DNR 2014, unpublished data).

In Massachusetts, there are seven known hibernacula. WNS was first confirmed in the State in the winter of 2007-2008. Previous to WNS confirmation in the State, the northern long-eared bat was found in relatively larger numbers for the species in some hibernacula. In 2013 and 2014 winter surveys conducted in Massachusetts hibernacula, either zero or one northern long-eared bat individual were found in all known hibernacula (Service 2015, unpublished data).

In New Hampshire, northern long-eared bats were known to inhabit at least nine mines and two World War II bunkers, and have been found in summer surveys (Brunkhurst 2012, unpublished data). The northern long-eared bat was one of the most common species captured (27 percent of captures) in the White Mountain National Forest in 1993-1994 (Sasse and Pekins 1996, pp. 93-95). WNS was confirmed in the State in the winter of 2008-2009. Data from both hibernacula surveys and summer surveys have shown a dramatic decline (99 percent) in northern long-eared bat numbers compared to pre-WNS numbers (NHFG 2013, in litt.). Results from hibernacula surveys conducted at four of New Hampshire's hibernacula in 2014 found no northern long-eared bats; previous to WNS infection, the species was found in relatively high numbers (

e.g.,

75-127 individuals) in most of these hibernacula. Furthermore, a researcher conducted mist-net surveys over 7 years pre-and post-WNS (2005-2011) at Surry Mountain Lake in Cheshire County, New Hampshire, and found a 98 percent decline in capture rate of northern long-eared bats (Moosman

et al.

2013, p. 554).

In New Jersey, one of the seven known northern long-eared bat hibernacula is a cave, and the rest are mines (Markuson 2011, unpublished data). Northern long-eared bats consisted of 6 to 14 percent of the total number of summer captures at Wallkill River National Wildlife Refuge from 2006-2010 (Kitchell and Wight 2011, in litt.). WNS was first confirmed in the State in the winter of 2008-2009. There have been limited consistent hibernacula and summer surveys conducted in the State to enable analyses of northern long-eared bat population trends pre- and post-WNS. Although small sample sizes precluded statistical comparison, Kitchell and Wight (2011, in litt.) and Bohrman and Fecske (2013, p. 77) documented a slight, overall decline in annual northern long-eared bat mist-net captures at Great Swamp National Wildlife Refuge following the outbreak of WNS. For 3 years prior to the disease's local emergence (2006-2008), northern long-eared bats represented 8-9 percent of total bats captured. Although the northern long-eared bat capture rate rose to 14 percent in 2009, it dropped to 6 percent in 2010, and further to 2 percent in 2012, suggesting a downward trend.

Historically, the northern long-eared bat was found in both summer and winter surveys conducted across Pennsylvania (Pennsylvania Game Commission (PGC) 2014, in litt.). Historically, the species was found in 112 hibernacula in the State. Fall swarm trapping conducted in September and October of 1988-1989, 1990-1991, and 1999-2000 at two hibernacula with large historical numbers of northern long-eared bats had total captures ranging from 6 to 30 bats per hour, which demonstrated that the species was abundant at these hibernacula (PGC 2012, unpublished data). WNS was first confirmed in the State in 2008-2009. Since that time, northern long-eared bat

winter survey numbers declined by 99 percent, in comparison to pre-WNS numbers (PGC 2014, in litt.; PGC 2014, unpublished data). Currently, the northern long-eared bat can still be found in portions of Pennsylvania during the summer; however, the number of summer captures continues to decline. The number of summer captures has declined an additional 15 percent annually, amounting to an overall decline of 76 percent (not including survey information from 2014) from pre-WNS capture rates. The PGC stated that the data support that the decline is attributable to WNS, rather than a lack of habitat or other direct impacts (PGC 2014, in litt.).

In Vermont, the northern long-eared bat was once one of the State's most common bats, but is now its rarest (Vermont Fish and Wildlife Department (VFWD) 2014, in litt.). Prior to 2009, the species was found in 16 hibernacula, totaling an estimated 458 animals, which was thought to be an underestimate due to the species' preference for hibernating in hibernacula cracks and crevices (VFWD 2014, unpublished data). WNS was confirmed in Vermont in the winter of 2007-2008. According to the VFWD, it is believed that all of the State's caves and mines that serve as bat hibernacula are infected with WNS. State-wide hibernacula, summer mist-net, and acoustic and fall swarm data collected in 2010 documented 93-100 percent declines in northern long-eared bat populations post-WNS (VFWD 2014, in litt.). In most recent surveys, few northern long-eared bats were found in three hibernacula in 2012-2013; however no individuals were found in any surveyed hibernacula in 2013-2014 winter surveys. Prior to WNS detection, summer capture data (from 2001-2007) indicated that northern long-eared bats comprised 19 percent of bats captured, and the northern long-eared bat was considered the second most common bat species in the State (Smith 2011, unpublished data). As for fall swarm data, in 2013, capture surveys at Aeolus Cave captured and identified 465 bats, only 3 of which were northern long-eared bats (VFWD 2014, in litt.).

In Virginia, the northern long-eared bat was historically considered “fairly common” during summer mist-net surveys; however, they were considered “uncommon” during winter hibernacula surveys and have been found in eight hibernacula (Reynolds 2012, unpublished data). WNS was first confirmed in Virginia in 2008-2009. Prior to WNS detection in the State (prior to 2011), 1.4 northern long-eared bats were captured per 1,000 units of effort during summer mist-net surveys conducted at sites Statewide. In 2011, there was an increase in captures, with 3.1 bats captured per unit effort. However, in 2013 in the same survey areas, 0.05 northern long-eared bats were captured per 1,000 units of effort, which amounts to a 96 percent decline in the population (Virginia Department of Game and Inland Fisheries (VDGIF) 2014, unpublished data). In 2013, over 85 percent of summer surveys resulted in no northern long-eared bat captures. Fall swarm trends have been similar, with capture rates per hour declining from 3.6 in 2009, to 0.3 in 2012, amounting to a decline of 92 percent (VDGIF 2014, unpublished data).

In West Virginia, northern long-eared bats were historically found regularly in hibernacula surveys, but typically in small numbers (fewer than 20 individuals) in caves (Stihler 2012, unpublished data). The species has also been found in 41 abandoned coal mines during fall swarming surveys conducted from 2002 to 2011, in the New River Gorge National River and Gauley River National Recreation Area, both managed by the NPS; the largest number observed was 157 in one of the NPS mines (NPS 2011, unpublished data). The species has been found in 104 total hibernacula in the State. WNS was first documented in hibernacula in the eastern portion of West Virginia in the winter of 2008-2009. Similar to some other WNS-affected States, northern long-eared bats can still be found across the State (similar pre- and post-WNS distribution); however, it is unclear if northern long-eared bat abundance is greater in West Virginia than other WNS-affected States and, therefore, whether WNS impacts are less severe to date. Across the State, northern long-eared bat summer captures decreased from 32.5 percent in 2008, and 33.8 percent in 2011, to around 20 percent for all subsequent years (West Virginia Division of Natural Resources 2014, unpublished data). However, percent capture data alone does not indicate whether the northern long-eared bat is declining in the State, especially if all bat captures are declining, as it only indicates their abundance relative to other bat species. Standardized catch per unit effort or other similar data are necessary to make population trend comparisons over time. Francl

et al.

(2012, p. 35) standardized data by captures per net night from 37 counties (31 counties pre-WNS (1997-2008) and 8 counties in 2010) in West Virginia, and had 1.4 captures per net-night pre-WNS and 0.3 captures per net night post-WNS. At one site monitored over time (Monongahela National Forest), average northern long-eared bat calls per mile of acoustic route declined by 31-81 percent (depending on software package used) from 2009-2012 (Johnson

et al.

2014, unpaginated). Similarly, mist-net capture rates declined by 93 percent from 2006-2008 to 2014 (Johnson

et al.

2014, unpaginated). Overall, although northern long-eared bats are still captured across West Virginia (

i.e.,

they have a similar distribution as they did pre-WNS), there are marked declines in capture rates.

In New York, the northern long-eared bat was historically one of the most widely distributed hibernating bat species in the State, identified in 90 out of 146 known bat hibernacula (New York State Department of Environmental Conservation (NYSDEC) 2014, in litt.). The species has also been observed in summer mist-net and acoustic surveys. Summer mist-net surveys conducted in New York (primarily for Indiana bat (

Myotis sodalis

) presence-absence surveys) from 2003-2008 resulted in a range of 0.21-0.47 northern long-eared bats per net night, and declined to 0.01 bats per net night in 2011 (Herzog 2012, unpublished data). New York is considered the epicenter for WNS, and the disease was first found in the State in the winter of 2006-2007. The NYSDEC confirmed that the decline experienced by this species due to WNS is both widespread and severe in the State (NYSDEC 2014, in litt.). Most hibernacula surveys conducted after the onset of WNS (2008 through 2013) found either one or zero northern long-eared bats (Service 2015, unpublished data). There are few long-term data sets for northern long-eared bats across the State, but one such site is the Fort Drum Military Installation, where acoustic surveys and mist-net surveys have monitored summer populations before (2003-2007) and after the onset of WNS (2008-2010). Ford

et al.

(2011, p. 130) reported significant declines (pre- vs. post-WNS) in mean acoustic call rates for northern long-eared bats as a part of this study at Fort Drum. No northern long-eared bats have been captured in mist-nets on Fort Drum since 2011.

There are two known hibernacula for bats in Rhode Island; however, no northern long-eared bats have been observed at either of these. There is also limited summer data available for the State; however, there were six summer records of northern long-eared bats from 2011 mist-net surveys in Washington County (Brown 2012, unpublished data).

We have no information regarding the species in the District of Columbia;

however WNS is presumed to be impacting the species because WNS occurs in all neighboring States.

Midwest Range

For purposes of organization in this rule, the midwestern geographic area includes the following States: Missouri, Illinois, Iowa, Indiana, Ohio, Michigan, Wisconsin, and Minnesota. The species is captured during summer mist-net surveys in varying abundance throughout most of the Midwest, and historically was considered one of the more frequently encountered bat species in the region. However, the species was historically observed infrequently and in small numbers during hibernacula surveys throughout the majority of its range in the Midwest. WNS has since been documented in Illinois, Indiana, Ohio, Michigan, Wisconsin, and Missouri. In Minnesota and Iowa, the presence of the fungus that causes WNS has been confirmed, but the disease itself has not been observed. Overall, clear declines in winter populations of northern long-eared bats have been observed in Ohio and Illinois (Service 2014, unpublished data).

There are no firm population size estimates for the northern long-eared bat rangewide; nor do we have the benefit of a viability analysis; however, a rough estimate of the population size in a portion of the Midwest has been calculated. That estimate shows there may have been more than four million bats in the six-State area that includes the States of Illinois, Indiana, Iowa, Ohio, Michigan, and Missouri (Meinke 2015, pers. comm.). This population size estimate (for the northern long-eared bat) was developed for the Midwest Wind Energy Multi-Species Habitat Conservation Plan (MSHCP) and was calculated by adjusting the 2013 Indiana bat winter population size (within the 6 States) based on the ratio of northern long-eared bats compared to Indiana bats in summer mist-net surveys. This estimate has limitations, however. The principal limitation is that the estimate is based on data that were primarily gathered prior to the onset of WNS in the Midwest; thus declines that have occurred in WNS-affected States are not reflected in the estimated number. Taking into account the documented effects of WNS in the Midwest to date (declines currently limited primarily to Ohio and Illinois), there may still be several million bats within the six-State area. Because post-WNS survey numbers for the species have not been included in this population estimate and WNS continues to spread throughout these 6 States, there is uncertainty as to the accuracy of this estimate, and it should be considered a rough estimate.

The northern long-eared bat has been documented in 76 of 114 counties in Missouri; its abundance in the summer is variable across the State and is likely related to the presence of suitable forest habitat and fidelity to historical summer areas. There are approximately 269 known northern long-eared bat hibernacula that are concentrated in the karst landscapes (characterized by underground drainage systems with sinkholes and caves) of central, eastern, and southern Missouri (Missouri Department of Conservation 2014, in litt.). Similar to other more predominantly karst areas, the northern long-eared bat is difficult to find in Missouri caves, and thus is rarely found in large numbers.

Pseudogymnoascus destructans

(Pd) was first detected in Missouri in the winter of 2009-2010; however, the majority of sites in the State that have been confirmed with WNS were confirmed more recently, during the winter of 2013-2014. Due to low numbers historically found in hibernacula in the State, it is difficult to determine if changes in count numbers are due to natural fluctuations or to WNS. However, there was one northern long-eared bat mortality observed during the winter of 2013-2014 (WNS Workshop 2014, pers. comm.). Furthermore, Elliott (2015, pers. comm.) noted that surveyors are detecting indicators of decline (changes in bat behavior) as well as actual declines in numbers of northern long-eared bats in hibernacula in the State. As for summer survey data, mist-net and acoustic surveys conducted across Missouri in the summer of 2014 indicate continued distribution throughout the State. However, there were fewer encounters with northern long-eared bats in some parts of the State in 2014, as compared to previous years. Specifically, surveys conducted on the Mark Twain National Forest in 2014 indicate a decline in the overall number of captures of all bat species, including fewer northern long-eared bats than expected (Amelon 2014, pers. comm.; Harris 2014, pers. comm.). Further, in southwest Missouri, northern long-eared bats have been encountered during mist-net surveys conducted on the Camp Crowder Training Site in 2006, 2013, and 2014. Overall, the number of northern long-eared bat captures has decreased since 2006, relative to the level of survey effort (number of net nights) (Missouri Army National Guard 2014, pp. 2-3; Robbins and Parris 2013, pp. 2-4, Robbins

et al.

2014, p. 5). Additionally, during a 2-year survey (2013-2014) at a State park in north-central Missouri, 108 northern long-eared bats were captured during the first year, whereas only 32 were captured during the second year, with a similar level of effort between years (Zimmerman 2014, unpublished data).

In Illinois, northern long-eared bats have been found in both winter hibernacula counts and summer mist-net surveys. Northern long-eared bats have been documented in 21 hibernacula in Illinois, most of which are in the southern portion of the State (Davis 2014, p. 5). Counts of more than 100 bats have been documented in some hibernacula, and a high of 640 bats was observed in a southern Illinois hibernaculum in 2005; however, much lower numbers of northern long-eared bats have been observed in most Illinois hibernacula (Service 2015, unpublished data). WNS was first discovered in the State during the winter of 2012-2013. Mortality of northern long-eared bats was observed 1 year later, during the winter of 2013-2014, at two of the State's major hibernacula, which are in the central part of the State. At one hibernaculum, there was a drop-off in numbers of northern long-eared bats observed over the winter, with 371 individuals occupying the hibernaculum in November of 2013, and by March of 2014, there were 10 individuals, which amounts to a 97 percent decline (Davis 2014, pp. 6-18). At the other hibernaculum, in March of 2013, there were 716 northern long-eared bats counted; in November of 2013, there were 171 individuals; and in March of 2014, there were 3 individuals, with a decline of over 99 percent (Davis 2014, pp. 6-18).

During the summer, northern long-eared bats have been observed in landscapes with a variety of forest cover throughout Illinois. Surveys conducted across the State, related to highway projects and research activities, resulted in the capture of northern long-eared bats in moderately forested counties in western and eastern Illinois (

e.g.,

Adams, Brown, and Edgar Counties), as well as in northern counties where forests are highly limited (

e.g.,

Will and Kankakee Counties) (Mengelkoch 2014, unpublished data; Powers 2014, unpublished data). Pre-WNS, northern long-eared bats were regularly caught in mist-net surveys in the Shawnee National Forest in southern Illinois (Kath 2013, pers. comm.). The average number of northern long-eared bats caught during surveys between 1999 and 2011 at Oakwood Bottoms in the Shawnee National Forest was fairly consistent (Carter 2012, pers. comm.). Summer bat surveys in 2007 and 2009

at Scott Air Force Base in St. Clair County resulted in a low numbers of captures (a few individuals) of northern long-eared bats, and, in 2014, no northern long-eared bats were encountered (Department of the Air Force 2007, pp. 10-14; Department of the Air Force 2010, pp. 11-12). Overall, summer surveys from Illinois have not documented a decline due to WNS to date.

In Iowa, there are only summer mist-net records for the northern long-eared bat, and the species has not been documented in hibernacula in the State. Northern long-eared bats have been recorded during many mist-net surveys since the 1970s. Recent records include documented captures in 13 of 99 counties across the central and southeastern portions of the State. In 2011, 8 individuals (including 3 lactating females) were captured in west-central Iowa (Howell 2011, unpublished data). During summer 2014, one nonreproductive female was tracked to a roost in Fremont County in southwest Iowa (Environmental Solutions and Innovations, Inc. 2014, pp. 52-56). In Scott County, southeastern Iowa, four female northern long-eared bats (two pregnant and two nonreproductive) were captured in June 2014, along the Wapsi River (Chenger and Tyburec 2014, p. 6). WNS has not been detected in Iowa to date; however, the fungus that causes WNS was first found at a hibernaculum in Iowa in the winter of 2011-2012.

Northern long-eared bats have been observed in both winter hibernacula surveys and, more commonly, in summer surveys in Indiana. Indiana has 25 known hibernacula with winter records of one or more northern long-eared bat. However, it is difficult to find large numbers of individuals in caves and mines during hibernation in Indiana (Whitaker and Mumford 2009, p. 208). Therefore, reliable winter population estimates are largely lacking in Indiana. WNS was confirmed in the State in the winter of 2010-2011. Although population trends are difficult to assess because of historically low numbers, mortality of northern long-eared bats due to WNS has been confirmed in the State (WNS Workshop 2014, pers. comm.). Historically, the northern long-eared bat was considered common throughout much of Indiana, and was the fourth or fifth most abundant bat species captured during summer surveys in the State in 2009. The species has been captured in at least 51 of 92 counties, often captured in mist-nets along streams, and was the most common bat taken by trapping at mine entrances (Whitaker and Mumford 2009, pp. 207-208). The abundance of northern long-eared bats appears to vary geographically within Indiana during the summer. For example, during three summers (1990, 1991, and 1992) of mist-netting in the northern half of Indiana, 37 northern long-eared bats were captured at 22 of 127 survey sites, and they only represented 4 percent of all bats captured (King 1993, p. 10). In contrast, northern long-eared bats were the most commonly captured bat species (38 percent of all bats captured) during three summers (2006, 2007, and 2008) of mist-netting on two State forests in south-central Indiana (Sheets

et al.

2013, p. 193). The differences in abundance in north versus south Indiana are due to there being few hibernacula in northern Indiana; consequently, migration distances to suitable hibernacula are great, and the species is not as common in summer surveys in the northern as in the southern portion of the State (Kurta 2013, in litt.). Long-term summer mist-netting surveys in Indiana have started to show a potential downward trend in northern long-eared bat numbers (

e.g.,

Indianapolis airport project, Interstate Highway 69 project; Service 2015, unpublished data); however, there was fluctuation in the count numbers from these surveys prior to WNS detection in the State, and it may be too early to confirm a downward trend based on these data. In Indiana, the Hardwood Ecosystem Experiment has collected summer mist-net data from 2006 through 2014 for the northern long-eared bat in Morgan-Monroe and Yellowwood State Forests, and has found consistent numbers of bats captured to date (Service 2015, unpublished data).

In Ohio, there are seven known hibernacula (Norris 2014, unpublished data) used by northern long-eared bat, and the species is regularly collected Statewide as incidental catches in summer mist-net surveys for Indiana bats (Boyer 2012, pers. comm.). WNS was first detected in the State in the winter of 2010-2011. Two hibernacula in Ohio contained approximately 90 percent of the State's overall winter bat population prior to WNS detection. The pre-WNS combined population average (5 years of survey data) for both sites was 282 northern long-eared bats, which declined to 17 northern long-eared bats in winter 2013-2014 (post-WNS). This amounts to a decline of northern long-eared bats from pre-WNS numbers of 90 percent in one of the hibernacula and 100 percent in the other (Norris 2014, pp. 19-20; Ohio Department of Natural Resources (ODNR) 2014, unpublished data). The (ODNR) conducted Statewide summer acoustic surveys along driving transects across the State from 2011 to 2014. Although they have not yet analyzed calls for individual species, such as the northern long-eared bat, initial results indicate a 56 percent decline in recorded

Myotis

bat species' calls over the 3-year period (ODNR 2014, unpublished data). Capture rates from mist-net surveys, which were primarily conducted to determine Indiana bat presence, were conducted pre-WNS detection in Ohio (2007-2011) and were compared to capture rates post-WNS (2012-2013), and it was found that capture rates of northern long-eared bats declined by 58 percent per mist-net site post-WNS (Service 2015, unpublished data). Several parks in Summit County, Ohio, have been conducting mist-net surveys for northern long-eared bats (among other bat species) since 2004 (Summit Metro Parks 2014, in litt.), with numbers fluctuating. Their data noted a potential slight decline in northern long-eared bat numbers prior to WNS (however, there was a slight increase in 2011), and after WNS was detected in the area, a sharp decline was documented in capture rates. In surveys conducted in 2013 and 2014, no northern long-eared bats were captured at any of the parks surveyed (where the species was previously found; Summit Metro Parks 2014, in litt.).

In Michigan, the northern long-eared bat is known from 36 (physical detections in 33 counties and acoustic detections from 3 additional counties) of 83 counties and is commonly encountered in parts of the northern Lower Peninsula and portions of the Upper Peninsula (Kurta 1982, p. 301; Kurta 2013, pers. comm.; Bohrman 2015, pers. comm.). WNS was first confirmed in Michigan in the winter of 2014-2015. Cave bat mortality was documented in 2014-2015, although mortality was not specifically confirmed for northern long-eared bats. The majority of hibernacula in Michigan are in the northern and western Upper Peninsula; therefore, there are very few cave-hibernating bats in general in the southern half of the Lower Peninsula during the summer because the distance to hibernacula is too great (Kurta 1982, pp. 301-302). It is thought that the few bats that do spend the summer in the southern half of the Lower Peninsula may hibernate in caves or mines in neighboring States (Kurta 1982, pp. 301-302).

In Wisconsin, the northern long-eared bat was historically reported as one of the least abundant bats, based on hibernacula surveys, acoustic surveys,

and summer mist-netting efforts (Amelon and Burhans 2006, pp. 71-72; Redell 2011, pers. comm.). However, summer surveys conducted in 2014 revealed a more widespread distribution than previously thought (Wisconsin Department of Natural Resources (WDNR) 2014, unpublished data). In the summer of 2014, WDNR radio-tracked 12 female northern long-eared bats in four regions in the State and collected information on selected roost tree species and characteristics (WNDR 2014, unpublished data). In addition, acoustic and mist-net data was collected by a pipeline project proponent in 2014, which resulted in new records for the species in many surveyed areas along a corridor from the northwest part through the southeast part of the State (WDNR 2014, unpublished data). The northern long-eared bat has been observed in 67 hibernacula in the State. WNS was confirmed in Wisconsin in the winter of 2013-2014. A recent population viability analysis in Wisconsin found that “there are no known natural refugia or highly resistant sites on the landscape, which will likely lead to statewide extinction of the species once WNS infects the major hibernacula” (Peery

et al.

2013, unpublished data; WDNR 2014, in litt.).

The northern long-eared bat is known from 11 hibernacula in Minnesota. WNS has not been detected in Minnesota; however, the fungus that causes WNS was detected in 2011-2012. Prior to 2014, there was little information on northern long-eared bat summer populations in the State. In 2014, passive acoustic surveys conducted at a new proposed mining area in central St. Louis County detected the presence of northern long-eared bats at each of 13 sites sampled, accounting for approximately 14 percent of all recorded bat calls (Smith

et al.

2014, pp. 3-4). Mist-net surveys in 2014 at seven sites on Camp Ripley Training Center, Morrison County, resulted in capture of 4 northern long-eared bats (5 percent of total captures), and at five sites on the Superior National Forest, Lake and St. Louis Counties, resulted in capture of 24 northern long-eared bats (55 percent of total captures) (Catton 2014, pp. 2-3). Acoustic and mist-net data were collected by a pipeline project proponent in 2014, which surveyed a 300-mile (mi) (483-kilometer (km)) corridor through the northern third of the State. Positive detections were recorded for Hubbard, Cass, Crow Wing, Aitkin, and Carlton Counties, and northern long-eared bats were the most common species captured by mist-net (Merjent 2014, unpublished data). Mist-net surveys were conducted the previous year (2013) on the Kawishiwi District of the Superior National Forest, and resulted in capture of 13 northern long-eared bats (38 percent of total captures) over nine nights of netting at eight sites (Grandmaison

et al.

2013, pp. 7-8).

Southern Range

For purposes of organization in this rule, southern geographic area includes: Alabama, Arkansas, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, and Tennessee. In the South, the northern long-eared bat is considered more common in States such as Kentucky and Tennessee, and less common in the southern extremes of its range (

e.g.,

Alabama, Georgia, and South Carolina). The absence of widespread survey efforts in several States is likely limiting the known range of the species, as well as information on its relative abundance (Armstrong 2015, pers. comm.). In the southern part of the species' range, Kentucky is the only State with Statewide survey data prior to 2010, primarily as a result of survey efforts for other listed bats species, such as the Indiana bat. WNS has been documented at many northern long-eared bat hibernacula in this region, with mortality confirmed at many sites.

Northern long-eared bats were historically observed in the majority of hibernacula in Kentucky and have been a commonly captured species during summer surveys (Lacki and Hutchinson 1999, p. 11; Hemberger 2015, pers. comm.). The northern long-eared bat has been documented throughout the majority of Kentucky, with historical records in 91 of its 120 counties. Eighty-five counties have summer records, and 68 of those include reproductive records (

i.e.,

captures of juveniles or pregnant, lactating, or post-lactating adult females) (Hemberger 2015, pers. comm.). WNS was first observed in Kentucky in 2011. Currently there are more than 60 known WNS-infected northern long-eared bat hibernacula in the State (Kentucky Department of Fish and Wildlife Resources (KDFWR) 2014, unpublished data). Bat mortality at infected sites was first documented in 2013, and increased in 2014 (KDFWR 2014, unpublished report). However, population trends are difficult to assess as northern long-eared bat numbers in these hibernacula have historically been variable. Summer survey data for Kentucky lack a standardized unit of effort and, therefore, cannot be used to assess population trends. However, Silvis

et al.

(2015, p. 6) documented significant summer population declines within four maternity colonies on Fort Knox Military Installation during their 3-year study (from 2012-2014), presumably due to WNS.

In Tennessee, northern long-eared bats have been observed in both summer mist-net surveys and winter hibernacula counts. Summer mist-net surveys from 2002 through 2013 resulted in the capture of more than 1,000 individuals, including males and juveniles or pregnant, lactating, or post-lactating adult females (Flock 2014, unpublished data). During the winter of 2009-2010, the Tennessee Wildlife Resource Agency (TWRA) began tracking northern long-eared bat populations and has since documented northern long-eared bats in 58 hibernacula, with individual hibernaculum populations ranging from 1 to 136 individuals (TWRA 2014, unpublished data). According to TWRA, Tennessee has over 9,000 caves and less than 2 percent of those have been surveyed, which led them to suggest that there could be additional unknown northern long-eared bat hibernacula in the State (TWRA 2013, in litt.). WNS was first documented in Tennessee in the winter of 2009-2010. WNS-related mortality was documented (including northern long-eared bat mortality) in 2014 (WNS Workshop 2014, pers. comm.); however, there is no pre-WNS data from these sites, and we cannot draw any conclusions regarding population trends based on hibernacula surveys. TWRA (2013, in litt.) indicates that summer mist-netting data for the eastern portion of the State showed a pre-WNS (2000-2008) capture frequency of 33 percent and post-WNS (2010-2012) capture frequency of 31 percent. These data do not have a standardized unit of effort, and, therefore, they cannot be used to assess population trends. Conversely, Lamb (2014, pers. comm.) observed declines in summer capture trends of several species of bats, including the northern long-eared bat, at Arnold Air Force Base in south-central Tennessee from 1998 to 2014. In the Great Smoky Mountains National Park, 2014 capture rates of northern long-eared bats in comparison to 2009-2012 declined by 71 to 94 percent (across all sites) based on unit of effort comparisons (NPS 2014, in litt.; Indiana State University 2015, in litt.).

In 2000, during sampling of bat populations in the Kisatchie National Forest, Louisiana, three northern long-eared bats, including two males and one lactating female, were collected. These were the first official records of the species from Louisiana, and the presence of a reproductive female likely represents a resident summer colony

(Crnkovic 2003, p. 715). Northern long-eared bats have not been documented using caves in Louisiana, including the five known caves that occur within 54 miles (87 km) of the collection site (Crnkovic 2003, p. 715). Neither WNS nor the fungus that cause WNS has been detected in Louisiana to date.

In Georgia, northern long-eared bat winter records are rare (Georgia Department of Natural Resources (GA DNR) 2014, in litt.). However, this species is commonly captured during summer mist-net surveys (GA DNR 2014, in litt.). Twenty-four summer records were documented between 2007 and 2011. Mist-net surveys were conducted in the Chattahoochee National Forest in 2001-2002 and 2006-2007, with 51 total individual records for the species (Morris 2012, unpublished data). WNS was first detected in the State in the winter of 2012-2013. With historically small numbers of northern long-eared bats found in hibernacula surveys in Georgia, we cannot draw conclusions regarding population trends based on hibernacula surveys. WNS-related mortality has been documented in cave bats in the State; however, northern long-eared bat mortality has not been documented to date.

Northern long-eared bats have been documented in 22 hibernacula in North Carolina. All known hibernacula are caves or mines located in the western part of the State (North Carolina Wildlife Resources Commission 2014, unpublished data), although summer records for the species exist for both the eastern and western parts of the State. In the summer of 2007, six northern long-eared bats were captured in Washington County, North Carolina (Morris

et al.

2009, p. 356). Both adults and juveniles were captured, suggesting that there is a reproducing resident population (Morris

et al.

2009, p. 359). Reproductive females and adult males have recently been documented in the northeastern part of the State. Mist-netting and acoustic data indicate that the northern long-eared bat may be active almost year-round in eastern portions of the State, likely due to mild winter temperatures and insect availability in coastal counties (North Carolina Department of Transportation 2014, in litt.). In North Carolina, WNS was first documented in the winter of 2008-2009. Northern long-eared bats have declined by 95 percent in hibernacula where WNS has been present for 2 or more years, with smaller declines documented in hibernacula infected for less than 2 years (Weeks and Graeter 2014, pers. comm.).

Northern long-eared bats are known from the mountain region of three counties in northwestern South Carolina: Oconee, Pickens, and Greenville. There are two known northern long-eared bat hibernacula in the State: one is a cave that had 26 northern long-eared bats present in 1995, but has not been surveyed since, and the other is a tunnel where only one bat was found in 2011 (Bunch 2011, unpublished data). In South Carolina, WNS was first documented in the winter of 2012-2013. Bat mortality due to WNS has not been documented to date. Winter northern long-eared bat records are infrequent in the State. When present in hibernacula counts, their numbers range from 24 (1995 survey of a Pickens County hibernaculum) to single records in Oconee County (South Carolina Department of Natural Resources 2015, in litt.). Thus, population trends cannot be determined based on hibernacula surveys, due to historically low numbers of northern long-eared bats found.

Northern long-eared bats are known from 41 hibernacula in Arkansas, although there are typically few individuals (

e.g.,

fewer than 10 individuals) observed (Sasse 2012, unpublished data). Saugey

et al.

(1993, p. 104) reported the northern long-eared bat to be rather common during fall swarming at abandoned mines in the Ouachita Mountains. Additionally, Heath

et al.

(1986, p. 35) found 57 pregnant females roosting in a mine in the spring of 1985. Summer surveys in the Ouachita Mountains of central Arkansas from 2000-2005 tracked 17 males and 23 females to 43 and 49 day-roosts, respectively (Perry and Thill 2007, pp. 221-222). In 2013 summer surveys in the Ozark St. Francis National Forest, the northern long-eared bat was the most common species captured (Service 2014, unpublished data). Pd was first detected in the State in the winter of 2011-2012; however, WNS was confirmed at different sites (than where Pd was first confirmed) in 2013-2014. Northern long-eared bat mortality was documented (five individuals) from one of the sites where WNS was first confirmed in 2013-2014 (WNS Workshop 2014, pers. comm.). Mortality of northern long-eared bats from WNS was observed in the State's largest hibernacula in 2015; 2015 surveys found 120 northern long-eared bats in that hibernacula, where counts in recent years often numbered 200 to 300 (Bitting 2015, pers. comm.).

Northern long-eared bats are known from two hibernacula in Alabama, where typically few individuals (

e.g.,

fewer than 20) are observed (Sharp 2014, unpublished data). Surveys conducted during the Southeast Bat Diversity Network bat blitz in 2008 reported the northern long-eared bat to be rather common in late summer/early fall swarm at known bat caves in Alabama (Sharp 2014, unpublished data). Summer surveys, mostly conducted between 2001 and 2008, in Alabama have documented 71 individual captures, including both males and reproductively active females (Sharp 2014, unpublished data). WNS was first documented in Alabama in the winter of 2011-2012.

The northern long-eared bat is known to occur in seven counties along the eastern edge of Oklahoma (Stevenson 1986, p. 41). The species is known from nine hibernacula, where typically they are observed in low numbers (

e.g.,

1 to 20 individuals). However, a larger colony uses a cave on the Ouachita National Forest in southeastern Oklahoma (LeFlore County) during the winter (9 to 96 individuals) and during the fall (9 to 463 individuals) (Perry 2014, pers. comm.). Northern long-eared bats have been recorded from 21 caves (7 of which occur on the Ozark Plateau National Wildlife Refuge) during the summer. The species has regularly been captured in summer mist-net surveys at cave entrances in Adair, Cherokee, Sequoyah, Delaware, and LeFlore Counties, and are often one of the most common bats captured during mist-net surveys at cave entrances in the Ozarks of northeastern Oklahoma (Stark 2013, pers. comm.; Clark and Clark 1997, p. 4). Small numbers of northern long-eared bats (typical range of 1 to 17 individuals) also have been captured during mist-net surveys along creeks and riparian zones in eastern Oklahoma (Stark 2013, pers. comm.; Clark and Clark 1997, pp. 4, 9-13). Neither WNS nor Pd has been detected in Oklahoma to date.

Although the northern long-eared bat was not considered abundant in Kentucky and Tennessee historically (Harvey

et al.

1991, p. 192), research conducted from 1990-2012 found the species abundant in summer mist-net surveys (Hemberger 2012, pers. comm.; Pelren 2011, pers. comm.; Lacki and Hutchinson 1999, p. 11). With the exception of Kentucky and possibly portions of Tennessee, western North Carolina, and northwestern Arkansas, where the species appears broadly distributed, there simply was not historically adequate effort expended to determine how abundant the species was in States such as South Carolina, Georgia, Alabama, Mississippi, and Louisiana. Due to this lack of surveys,

historical variability of winter populations, or lack of standardized data, it is difficult to draw conclusions about winter population trends pre- and post-WNS introduction in this region. Similarly, summer population trends are also difficult to summarize at this time due to a lack of surveys or standardized data.

Western Range

For purposes of organization in this rule, this region includes the following States: South Dakota, North Dakota, Nebraska, Wyoming, Montana, and Kansas. The northern long-eared bat is historically less common in the western portion of its range than in the northern portion of the range (Amelon and Burhans 2006, p. 71), and is considered common in only small portions of the western part of its range (

e.g.,

Black Hills of South Dakota) and uncommon or rare in the western extremes of the range (

e.g.,

Wyoming, Kansas, Nebraska) (Caceres and Barclay 2000, p. 2); however, there has been limited survey effort throughout much of this part of the species' range. To date, WNS has not been found in any of these States.

The northern long-eared bat has been observed hibernating and residing during the summer in the Black Hills National Forest in South Dakota and is considered abundant in the region. Capture and banding data for survey efforts in the Black Hills of South Dakota and Wyoming showed northern long-eared bats to be the second most common bat banded (159 of 878 total bats) during 3 years of survey effort (Tigner and Aney 1994, p. 4). South Dakota contains 21 known hibernacula, all within the Black Hills, 9 of which are abandoned mines (Bessken 2015, pers. comm.). The largest number of northern long-eared bats was observed in a hibernaculum near Hill City, South Dakota; 40 northern long-eared bats were observed in this mine in the winter of 2002-2003 (Tigner and Stukel 2003, pp. 27-28). A summer population was found in the Dakota Prairie National Grassland and Custer National Forest in 2005 (Lausen undated, unpublished data). Using mist-nets and echolocation detectors, northern long-eared bats have also been observed in small numbers in the Buffalo Gap National Grasslands (Tigner 2004, pp. 13-30; Tigner 2005, pp. 7-18). Additionally, northern long-eared bats, including some pregnant females, have been captured during the summer along the Missouri River in South Dakota (Swier 2006, p. 5; Kiesow and Kiesow 2010, pp. 65-66). Swier (2003, p. 25) found that of 52 bats collected in a survey along the Missouri River, 42 percent were northern long-eared bats. Acoustic data recorded by bat monitoring stations operated by the South Dakota Department of Game, Fish, and Parks (SDDGFP) also detected the northern long-eared bat sporadically throughout the State (across 16 counties) in 2011 and 2012 (SDDGFP 2014, in litt.)

Summer surveys in North Dakota (2009-2011) documented the species in the Turtle Mountains, the Missouri River Valley, and the Badlands (Gillam and Barnhart 2011, pp. 10-12). No northern long-eared bat hibernacula are known within North Dakota. During the winters of 2010-2013, Barnhart (2014, unpublished; Western Area Power Administration 2015, in litt.) documented 3 bat hibernacula and 18 potential hibernacula in Theodore Roosevelt National Park; however, no northern long-eared bat were found.

Northern long-eared bats have been observed at two quarries located in east-central Nebraska (Geluso 2011, unpublished data). However, the species is known to summer in the northwestern parts of Nebraska, specifically Pine Ridge in Sheridan County, and a small maternity colony has been recently documented (Geluso

et al.

2014, p. 2). A reproducing population has also been documented north of Valentine in Cherry County (Benedict

et al.

2000, pp. 60-61). During an acoustic survey conducted during the summer of 2012, the species was present in Cass County (east-central Nebraska). Similarly, acoustic surveys in Holt County, on the Grand Prairie Wind Farm, observed the northern long-eared bat at five of seven sites (Mattson

et al.

2014, pp. 2-3). Limestone quarries in Cass County are used as hibernacula by this species and others (White

et al.

2012, p. 3). White

et al.

(2012, p. 2) state that the bat is uncommon or absent from extreme southeastern Nebraska; however, surveys in Otoe County found two northern long-eared bats, a female and a male, and telemetry surveys identified roosts in the county (Brack and Brack 2014, pp. 52-53).

During acoustic and mist-net surveys conducted throughout Wyoming in the summers of 2008-2011, 32 separate observations of northern long-eared bats were made in the northeast part of the State, and breeding was confirmed (U.S. Forest Service (USFS) 2006, unpublished data; Wyoming Game and Fish Department (WGFD) 2012, unpublished data). Northern long-eared bats have also been observed at Devils Tower National Monument in Wyoming during the summer months, and primarily used forested areas of the monument (NPS 2014, in litt.). To date, there are no known hibernacula in Wyoming, and it is unclear if there are existing hibernacula used by northern long-eared bats, although the majority of potential hibernacula (abandoned mines) within the State occur outside of the northern long-eared bat's range (Tigner and Stukel 2003, p. 27; WGFD 2012, unpublished data).

Montana has only one known record of a northern long-eared bat in the State, a male collected in an abandoned coal mine in 1978 in Richland County (Montana Fish, Wildlife, and Parks (MFWP) 2012, unpublished data). The species has not been reported in eastern Montana since the 1978 record, despite mist-net and acoustic surveys conducted in the eastern portion of the State through 2014 (Montana Natural Heritage Program 2015, in litt.). The specimen of this single bat collected in the State is currently undergoing genetic testing to determine whether the record is indeed a northern long-eared bat (Montana Natural Heritage Program 2015, in litt.; MFWP 2015, in litt.).

In Kansas, the northern long-eared bat was first documented in 1951, when individual bats were documented hibernating in the gypsum mines of Marshall County (Schmidt

et al.

2015, unpaginated). The status of the gypsum mines as hibernaculum in Kansas is widely unknown. Northern long-eared bats were thought to only migrate through central Kansas until pregnant females were discovered in north-central Kansas in 1994 and 1995 (Sparks and Choate 1995, p. 190). Since then, northern long-eared bats have been considered relatively common in riparian woodlands in Phillips, Rooks, Graham, Osborne, Ellis, and Russel Counties (Schmidt

et al.

2015, unpaginated).

Canadian Range

The northern long-eared bat occurs throughout the majority of the forested regions of Canada, although it is found in higher abundance in eastern Canada than in western Canada, similar to in the United States (Caceres and Pybus 1997, p. 6). However, the scarcity of records in the western parts of Canada may be due to more limited survey efforts. It has been estimated that approximately 40 percent of the northern long-eared bat's global range is in Canada (Committee on the Status of Endangered Wildlife in Canada (COSEWIC) 2012, p. 9). The population size for the northern long-eared bat in Canada is unknown, but likely numbered over a million prior to the 2010 arrival of WNS in Canada (COSEWIC 2013, p. xv1). The range of the northern long-eared bat in Canada includes Alberta, British Columbia,

Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Prince Edward Island, Ontario, Quebec, Saskatchewan, and Yukon (COSEWIC 2012, p. 4). There are no records of the species overwintering in Yukon and Northwest Territories (COSEWIC 2012, p. 9).

Habitat

Winter Habitat

Northern long-eared bats predominantly overwinter in hibernacula that include caves and abandoned mines. Hibernacula used by northern long-eared bats vary in size from large, with large passages and entrances (Raesly and Gates 1987, p. 20), to much smaller hibernacula (Kurta 2013, in litt.). These hibernacula have relatively constant, cooler temperatures (0 to 9 degrees Celsius (°C) (32 to 48 degrees Fahrenheit (°F))) (Raesly and Gates 1987, p. 18; Caceres and Pybus 1997, p. 2; Brack 2007, p. 744), with high humidity and no air currents (Fitch and Shump 1979, p. 2; van Zyll de Jong 1985, p. 94; Raesly and Gates 1987, p. 118; Caceres and Pybus 1997, p. 2). The sites favored by northern long-eared bats are often in very high humidity areas, to such a large degree that droplets of water are often observed on their fur (Hitchcock 1949, p. 52; Barbour and Davis 1969, p. 77). Northern long-eared bats, like eastern small-footed bats (

Myotis leibii

) and big brown bats (

Eptesicus fuscus

), typically prefer cooler and more humid conditions than little brown bats, but are less tolerant of drier conditions than eastern small-footed bats and big brown bats (Hitchcock 1949, pp. 52-53; Barbour and Davis 1969, p. 77; Caceres and Pybus 1997, p. 2). Northern long-eared bats are typically found roosting in small crevices or cracks in cave or mine walls or ceilings, sometimes with only the nose and ears visible, and thus are easily overlooked during surveys (Griffin 1940a, pp. 181-182; Barbour and Davis 1969, p. 77; Caire

et al.

1979, p. 405; van Zyll de Jong 1985, p. 9; Caceres and Pybus 1997, p. 2; Whitaker and Mumford 2009, pp. 209-210). Caire

et al.

(1979, p. 405) and Whitaker and Mumford (2009, p. 208) commonly observed individuals exiting caves with mud and clay on their fur, also suggesting the bats were roosting in tighter recesses of hibernacula. Additionally, northern long-eared bats have been found hanging in the open, although not as frequently as in cracks and crevices (Barbour and Davis 1969, p. 77; Whitaker and Mumford 2009, pp. 209-210). In 1968, Whitaker and Mumford (2009, pp. 209-210) observed three northern long-eared bats roosting in the hollow core of stalactites in a small cave in Jennings County, Indiana.

To a lesser extent, northern long-eared bats have also been observed overwintering in other types of habitat that resemble cave or mine hibernacula, including abandoned railroad tunnels, (Service 2015, unpublished data). Also, in 1952, three northern long-eared bats were found hibernating near the entrance of a storm sewer in central Minnesota (Goehring 1954, p. 435). Kurta

et al.

(1997, p. 478) found northern long-eared bats hibernating in a hydroelectric dam facility in Michigan. In Massachusetts, northern long-eared bats have been found hibernating in the Sudbury Aqueduct (Massachusetts Department of Fish and Game 2012, unpublished data). Griffin (1945, p. 22) found northern long-eared bats in December in Massachusetts in a dry well, and commented that these bats may regularly hibernate in “unsuspected retreats” in areas where caves or mines are not present. Although confamilial (belonging to the same taxonomic family) bat species (

e.g.,

big brown bats) have been found using non-cave or mine hibernacula, including attics and hollow trees (Neubaum

et al.

2006, p. 473; Whitaker and Gummer 1992, pp. 313-316), northern long-eared bats have only been observed over-wintering in suitable caves, mines, or habitat with the same types of conditions found in suitable caves or mines to date.

Summer Habitat

I. Summer Roost Characteristics

During the summer, northern long-eared bats typically roost singly or in colonies underneath bark or in cavities or crevices of both live trees and snags (Sasse and Pekins 1996, p. 95; Foster and Kurta 1999, p. 662; Owen

et al.

2002, p. 2; Carter and Feldhamer 2005, p. 262; Perry and Thill 2007, p. 222; Timpone

et al.

2010, p. 119). Males' and nonreproductive females' summer roost sites may also include cooler locations, including caves and mines (Barbour and Davis 1969, p. 77; Amelon and Burhans 2006, p. 72). Northern long-eared bats have also been observed roosting in colonies in human-made structures, such as in buildings, in barns, on utility poles, behind window shutters, and in bat houses (Mumford and Cope 1964, p. 72; Barbour and Davis 1969, p. 77; Cope and Humphrey 1972, p. 9; Burke 1999, pp. 77-78; Sparks

et al.

2004, p. 94; Amelon and Burhans 2006, p. 72; Whitaker and Mumford 2009, p. 209; Timpone

et al.

2010, p. 119; Bohrman and Fecske 2013, pp. 37, 74; Joe Kath 2013, pers. comm.).

The northern long-eared bat appears to be somewhat flexible in tree roost selection, selecting varying roost tree species and types of roosts throughout its range. Northern long-eared bats have been documented in roost in many species of trees, including: black oak (

Quercus velutina

), northern red oak (

Quercus rubra

), silver maple (

Acer saccharinum

), black locust (

Robinia pseudoacacia

), American beech (

Fagus grandifolia

), sugar maple (

Acer saccharum

), sourwood (

Oxydendrum arboreum

), and shortleaf pine (

Pinus echinata

) (

e.g.,

Mumford and Cope 1964, p. 72; Clark

et al.

1987, p. 89; Sasse and Pekins 1996, p. 95; Foster and Kurta 1999, p. 662; Lacki and Schwierjohann 2001, p. 484; Owen

et al.

2002, p. 2; Carter and Feldhamer 2005, p. 262; Perry and Thill 2007, p. 224; Timpone

et al.

2010, p. 119). Northern long-eared bats most likely are not dependent on certain species of trees for roosts throughout their range; rather, many tree species that form suitable cavities or retain bark will be used by the bats opportunistically (Foster and Kurta 1999, p. 668). Carter and Feldhamer (2005, p. 265) hypothesized that structural complexity of habitat or available roosting resources are more important factors than the actual tree species.

In the majority of northern long-eared bat telemetry studies, roost trees consist predominantly of hardwoods (

e.g.,

Foster and Kurta 1999, p. 662; Lacki and Schwierjohann 2001, p. 484; Broders and Forbes 2004, p. 606). Broders and Forbes (2004, p. 605) reported that female northern long-eared bat roosts in New Brunswick were 24 times more likely to be shade-tolerant, deciduous trees than conifers. Of the few northern long-eared bat telemetry studies in which conifers represented a large proportion of roosts, most were reported as snags (

e.g.,

Cryan

et al.

2001, p. 45; Jung

et al.

2004, p. 329). Overall, these data suggest that hardwood trees most often provide the structural and microclimate conditions preferred by maternity colonies and groups of females, which have more specific roosting needs than solitary males (Lacki and Schwierjohann 2001, p. 484), although softwood snags may offer more suitable roosting habitat for both genders than hardwoods (Perry and Thill 2007, p. 222; Cryan

et al.

2001, p. 45). One reason deciduous snags may be preferred over conifer snags is increased resistance to decay, and consequently roost longevity, of the former (USFS 1998).

Many studies have documented the northern long-eared bat's selection of both live trees and snags, with a range of 10 to 53 percent selection of live roosts found (Sasse and Pekins 1996, p. 95; Foster and Kurta 1999, p. 668; Lacki and Schwierjohann 2001, p. 484; Menzel

et al.

2002, p. 107; Carter and Feldhamer 2005, p. 262; Perry and Thill 2007, p. 224; Timpone

et al.

2010, p. 118). Foster and Kurta (1999, p. 663) found 53 percent of roosts in Michigan were in living trees, whereas in New Hampshire, 66 percent of roosts were in live trees (Sasse and Pekins 1996, p. 95). The use of live trees versus snags may reflect the availability of such structures in study areas (Perry and Thill 2007, p. 224) and the flexibility in roost selection when there is a sympatric bat species present (

e.g.,

Indiana bat) (Timpone

et al.

2010, p. 120). Most telemetry studies describe a greater number of dead than live roosts (

e.g.,

Cryan

et al.

2001, p. 45; Lacki and Schwierjohann 2001, p. 486; Timpone

et al.

2010, p. 120; Silvis

et al.

2012, p. 3). A significant preference for dead or dying trees was reported for northern long-eared bats in Kentucky (Silvis

et al.

2012, p. 3), Illinois, and Indiana; in South Dakota (Cryan

et al.

2001, p. 45) and West Virginia, northern long-eared bat roost plots contained a higher than expected proportion of snags (Owen

et al.

2002, p. 4). Moreover, most studies reporting a higher proportion of live roosts included trees that had visible signs of decline, such as broken crowns or dead branches (

e.g.,

Foster and Kurta 1999, pp. 662,663; Ford

et al.

2006, p. 20). Thus, the tendency for northern long-eared bats (particularly large maternity colonies) to use healthy live trees appears to be fairly low.

In tree roosts, northern long-eared bats are typically found beneath loose bark or within cavities and have been found to use both exfoliating bark and crevices to a similar degree for summer roosting habitat (Foster and Kurta 1999, p. 662; Lacki and Schwierjohann 2001, p. 484; Menzel

et al.

2002, p. 110; Owen

et al.

2002, p. 2; Perry and Thill 2007, p. 222; Timpone

et al.

2010, p. 119).

Canopy coverage at northern long-eared bat roosts has ranged from 56 percent in Missouri (Timpone

et al.

2010, p. 118), to 66 percent in Arkansas (Perry and Thill 2007, p. 223), to greater than 75 percent in New Hampshire (Sasse and Pekins 1996, p. 95), to greater than 84 percent in Kentucky (Lacki and Schwierjohann 2001, p. 487). Studies in New Hampshire and British Columbia have found that canopy coverage around roosts is lower than in available stands (Sasse and Pekins 1996, p. 95). Females tend to roost in more open areas than males, likely due to the increased solar radiation, which aids pup development (Perry and Thill 2007, p. 224). Fewer trees surrounding maternity roosts may also benefit juvenile bats that are starting to learn to fly (Perry and Thill 2007, p. 224). However, in southern Illinois, northern long-eared bats were observed roosting in areas with greater canopy cover than in random plots (Carter and Feldhamer 2005, p. 263). Roosts are also largely selected below the canopy, which could be due to the species' ability to exploit roosts in cluttered environments; their gleaning behavior suggests an ability to easily maneuver around obstacles (Foster and Kurta 1999, p. 669; Menzel

et al.

2002, p. 112).

Results from studies have found the diameters of roost trees selected by northern long-eared bats vary greatly. Some studies have found that the diameter-at-breast height (dbh) of northern long-eared bat roost trees was greater than random trees (Lacki and Schwierjohann 2001, p. 485), and others have found both dbh and height of selected roost trees to be greater than random trees (Sasse and Pekins 1996, p. 97; Owen

et al.

2002 p. 2). However, other studies have found that roost tree mean dbh and height did not differ from random trees (Menzel

et al.

2002, p. 111; Carter and Feldhamer 2005, p. 266). Based on a consolidation of data from across the northern long-eared bat range (Sasse and Pekins 1996, pp. 95-96; Schultes 2002, pp. 49, 51; Perry 2014, pers. comm.; Lereculeur 2013, pp. 52-54; Carter and Feldhamer 2005, p. 263; Foster and Kurta 1999, p. 663; Lacki and Schwierjohann 2001, pp. 484-485; Owens

et al.

2002, p. 3; Timpone

et al.

2010, p. 118; Lowe 2012, p. 61; Perry and Thill 2007, p. 223; Lacki

et al.

2009, p. 1,171), roost tree dbh most commonly used (close to 80 percent of over 400 documented maternity tree roosts) by northern long-eared bat maternity colonies range from 10 to 25 centimeters (cm) (4 to 10 inches).

As for elevation of northern long-eared bat roosts, Lacki and Schwierjohann (2001, p. 486) have found that northern long-eared bats roost more often on upper and middle slopes than lower slopes, which suggests a preference for higher elevations, possibly due to increased solar heating. Silvis

et al.

(2012, p. 4), found that selection of mid- and upper-slope roost areas may also be a function of the landscape position, whereby forest stands are most subjected to disturbance (

e.g.,

wind, more intense fire, more drought stress, higher incidence of insect attack) that in turn creates suitable roost conditions among multiple snags and trees within the stand.

Some studies have found tree roost selection to differ slightly between male and female northern long-eared bats. Some studies have found male northern long-eared bats more readily using smaller diameter trees for roosting than females, suggesting males are more flexible in roost selection than females (Lacki and Schwierjohann 2001, p. 487; Broders and Forbes 2004, p. 606; Perry and Thill 2007, p. 224). In the Ouachita Mountains of Arkansas, both sexes primarily roosted in pine snags, although females roosted in snags surrounded by fewer midstory trees than did males (Perry and Thill 2007, p. 224). In New Brunswick, Canada, Broders and Forbes (2004, pp. 606-607) found that there was spatial segregation between male and female roosts, with female maternity colonies typically occupying more mature, shade-tolerant deciduous tree stands and males occupying more conifer-dominated stands. Data from West Virginia at the Fernow Experimental Forest and the former Westvaco Ecosystem Research Forest (both of which contain both relatively unmanaged, older, mature stands; early successional/mid-age stands; and fire-modified stands) suggest that females choose smaller diameter, suppressed understory trees, whereas males often chose larger, sometimes canopy-dominant trees for roosts, perhaps in contrast to other tree-roosting myotids such as Indiana bats (Menzel

et al.

2002, p. 112; Ford

et al.

2006, p. 16; Johnson

et al.

2009a, p. 239). A study in northeastern Kentucky found that males did not use colony roosting sites and were typically found occupying cavities in live hardwood trees, while females formed colonies more often in both hardwood and softwood snags (Lacki and Schwierjohann 2001, p. 486). However, males and nonreproductively active females are found roosting within home ranges of known maternity colonies the majority of the time (1,712 of 1,825 capture records or 94 percent) within Kentucky (Service 2014, unpublished data), suggesting little segregation between reproductive females and other individuals in summer.

II. Summer Roosting Behavior

Northern long-eared bats actively form colonies in the summer (Foster and Kurta 1999, p. 667) and exhibit fission-fusion behavior (Garroway and Broders 2007, p. 961), where members frequently coalesce to form a group (fusion), but composition of the group is in flux, with individuals frequently departing to be solitary or to form

smaller groups (fission) before returning to the main unit (Barclay and Kurta 2007, p. 44). As part of this behavior, northern long-eared bats switch tree roosts often (Sasse and Pekins 1996, p. 95), typically every 2 to 3 days (Foster and Kurta 1999, p. 665; Owen

et al.

2002, p. 2; Carter and Feldhamer 2005, p. 261; Timpone

et al.

2010, p. 119). In Missouri, the longest time spent roosting in one tree was 3 nights; however, up to 11 nights spent roosting in a human-made structure has been documented (Timpone

et al.

2010, p. 118). Bats switch roosts for a variety of reasons, including temperature, precipitation, predation, parasitism, sociality, and ephemeral roost sites (Carter and Feldhamer 2005, p. 264). Ephemeral roost sites, with the need to proactively investigate new potential roost trees prior to their current roost tree becoming uninhabitable (

e.g.,

tree falls over), may be the most likely scenario (Kurta

et al.

2002, p. 127; Carter and Feldhamer 2005, p. 264; Timpone

et al.

2010, p. 119).

Fission-fusion dynamics also drives maternal roosting behaviors and relatedness within social groups of northern long-eared bats. Patriquin

et al.

(2013, p. 952) found that the average relatedness of social group members (northern long-eared bat individuals in nearby colonies that may occasionally share roosts) was low; however, familiar pairs of females (females that frequently roosted together) were more closely related than expected by chance. Consistent with these genetic findings, Garroway and Broders (2007, p. 960), Patriquin

et al.

(2010, p. 904), and Johnson

et al.

(2011, p. 227) observed nonrandom roosting behaviors, with some female northern long-eared bats roosting more frequently together than with other females.

Roosts trees used by northern long-eared bats are often in fairly close proximity to each other within the species' summer home range. For example, in Missouri, Timpone

et al.

(2010, p. 118) radio-tracked 13 northern long-eared bats to 39 roosts and found the mean distance traveled between roost trees was 0.67 km (0.42 mi) (range 0.05-3.9 km (0.03-2.4 mi)). In Michigan, the longest distance moved by the same bat between roosts was 2 km (1.2 mi), and the shortest was 6 meters (m) (20 feet (ft)) (Foster and Kurta 1999, p. 665). In the Ouachita Mountains of Arkansas, Perry and Thill (2007, p. 22) found that individuals moved among snags that were within less than 2 hectares (ha) (5 acres). Johnson

et al.

(2011, p. 227) found that northern long-eared bats form social groups in networks of roost trees often centered on a central-node roost. Central-node roost trees may be similar to Indiana bat primary roost trees (locations for information exchange, thermal buffering), but they were identified by the degree of connectivity with other roost trees rather than by the number of individuals using the tree (Johnson

et al.

2011, p. 228).

Spring Staging

Spring staging for the northern long-eared bat is the time period between winter hibernation and spring migration to summer habitat (Whitaker and Hamilton 1998, p. 80). During this time, bats begin to gradually emerge from hibernation, exit the hibernacula to feed, but re-enter the same or alternative hibernacula to resume daily bouts of torpor (state of mental or physical inactivity) (Whitaker and Hamilton 1998, p. 80). The staging period for the northern long-eared bat is likely short in duration (Whitaker and Hamilton 1998, p. 80; Caire

et al.

1979, p. 405). In Missouri, Caire

et al.

(1979, p. 405) found that northern long-eared bats moved into the staging period in mid-March through early May. In Michigan, Kurta

et al.

(1997, p. 478) determined that by early May, two-thirds of the

Myotis

species, including the northern long-eared bat, had dispersed to summer habitat. Variation in timing (onset and duration) of staging for Indiana bats was based on latitude and weather (Service 2007, pp. 39-40, 42); similarly, timing of staging for northern long-eared bats is likely based on these same factors.

Fall Swarming

The swarming season fills the time between the summer and winter seasons (Lowe 2012, p. 50) and the purpose of swarming behavior may include: Introduction of juveniles to potential hibernacula, copulation, and stopping over sites on migratory pathways between summer and winter regions (Kurta

et al.

1997, p. 479; Parsons

et al.

2003, p. 64; Lowe 2012, p. 51; Randall and Broders 2014, pp. 109-110). The swarming season for some species of the genus

Myotis

begins shortly after females and young depart maternity colonies (Fenton 1969, p. 601). During this time, both male and female northern long-eared bats are present at swarming sites (often with other species of bats). During this period, heightened activity and congregation of transient bats around caves and mines is observed, followed later by increased sexual activity and bouts of torpor prior to winter hibernation (Fenton 1969, p. 601; Parsons

et al.

2003, pp. 63-64; Davis and Hitchcock 1965, pp. 304-306). For the northern long-eared bat, the swarming period may occur between July and early October, depending on latitude within the species' range (Fenton 1969, p. 598; Kurta

et al.

1997, p. 479; Lowe 2012, p. 86; Hall and Brenner 1968, p. 780; Caire

et al.

1979, p. 405). The northern long-eared bat may investigate several cave or mine openings during the transient portion of the swarming period, and some individuals may use these areas as temporary daytime roosts or may roost in forest habitat adjacent these sites (Kurta

et al.

1997, pp. 479, 483; Lowe 2012, p. 51). Many of the caves and mines associated with swarming are also used as hibernacula for several species of bats, including the northern long-eared bat (Fenton 1969, p. 599; Glover and Altringham 2008, p. 1498; Randall and Broders 2014, p. 109; Kurta

et al.

1997, p. 484; Whitaker and Rissler 1992a, p. 132).

Little is known about northern long-eared bat roost selection outside of caves and mines during the swarming period (Lowe 2012, p. 6). Lowe (2012, pp. 32, 58, 63) documented northern long-eared bats in the Northeast roosting in both coniferous and deciduous trees or stumps as far away as 3 miles (7 km) from the swarming site. Although Lowe (2012, pp. 61, 64) hypothesized that tree roosts used during the fall swarming season would be similar to summer roosts, there was a difference found between summer and fall in the variation in distances bats traveled from the capture site to roost, roost orientation, and greater variation of roost types (

e.g.,

roost species, size, decay class) in the fall. Greater variation among roosts during the swarming season may be a result of the variation in energy demands that individual northern long-eared bats exhibit during this time (Lowe 2012, p. 64; Barclay and Kurta 2007, pp. 31-32).

Biology

Hibernation

Northern long-eared bats hibernate during the winter months to conserve energy from increased thermoregulatory demands and reduced food resources. To increase energy savings, individuals enter a state of torpor, when internal body temperatures approach ambient temperature, metabolic rates are significantly lowered, and immune function declines (Thomas

et al.

1990, p. 475; Thomas and Geiser 1997, p. 585; Bouma

et al.

2010, p. 623). Periodic arousal from torpor naturally occurs in all hibernating mammals (Lyman

et al.

1982, p. 92), although arousals remain among the least understood of hibernation phenomena (Thomas and

Geiser 1997, p. 585). Numerous factors (

e.g.,

reduction of metabolic waste, body temperature, and water balance) have been proposed to account for the occurrence and frequency of arousals (Thomas and Geiser 1997, p. 585). Each time a bat arouses from torpor, it uses a significant amount of energy to warm its body and increase its metabolic rate. The cost and number of arousals are the two key factors that determine energy expenditures of hibernating bats in winter (Thomas

et al.

1990, p. 475). For example, little brown bats used as much fat during a typical arousal from hibernation as would be used during 68 days of torpor, and arousals and subsequent activity may constitute 84 percent of the total energy used by hibernating bats during the winter (Thomas

et al.

1990, pp. 477-478).

In general, northern long-eared bats arrive at hibernacula in August or September, enter hibernation in October and November, and emerge from the hibernacula in March or April (Caire

et al.

1979, p. 405; Whitaker and Hamilton 1998, p. 100; Amelon and Burhans 2006, p. 72). However, hibernation may begin as early as August (Whitaker and Rissler 1992b, p. 56). In Copperhead Cave (a mine) in west-central Indiana, the majority of bats enter hibernation during October, and spring emergence occurs from about the second week of March to mid-April (Whitaker and Mumford 2009, p. 210). In Indiana, northern long-eared bats become more active and start feeding outside the hibernaculum in mid-March, evidenced by stomach and intestine contents. This species also showed spring activity earlier than little brown bats and tri-colored bats (

Perimyotis subflavus

) (Whitaker and Rissler 1992b, pp. 56-57). In northern latitudes, such as in upper Michigan's copper-mining district, hibernation may begin as early as late August and continue for 8 to 9 months (Stones and Fritz, 1969, p. 81; Fitch and Shump 1979, p. 2). Northern long-eared bats have shown a high degree of philopatry (using the same site multiple years) for a hibernaculum (Pearson 1962, p. 30), although they may not return to the same hibernaculum in successive seasons (Caceres and Barclay 2000, p. 2).

Typically, northern long-eared bats were not abundant and composed a small proportion of the total number of bats observed hibernating in a hibernaculum (Barbour and Davis 1969, p. 77; Mills 1971, p. 625; Caire

et al.

1979, p. 405; Caceres and Barclay 2000, pp. 2-3). Although usually observed in small numbers, the species typically inhabits the same hibernacula with large numbers of other bat species, and occasionally are found in clusters with these other bat species. Other species that commonly occupy the same habitat include little brown bat, big brown bat, eastern small-footed bat, tri-colored bat, and Indiana bat (Swanson and Evans 1936, p. 39; Griffin 1940a, p. 181; Hitchcock 1949, pp. 47-58; Stones and Fritz 1969, p. 79). Whitaker and Mumford (2009, pp. 209-210), however, infrequently found northern long-eared bats hibernating beside little brown bats, Indiana bats, or tri-colored bats. Barbour and Davis (1969, p. 77) found that the species was rarely recorded in concentrations of more than 100 in a single hibernaculum.

Northern long-eared bats have been observed moving among hibernacula throughout the winter, which may further decrease population estimates (Griffin 1940a, p. 185; Whitaker and Rissler 1992a, p. 131; Caceres and Barclay 2000, pp. 2-3). Whitaker and Mumford (2009, p. 210) found that this species flies in and out of some mines and caves in southern Indiana throughout the winter. In particular, the bats were active at Copperhead Cave periodically all winter, with northern long-eared bats being more active than other species (such as little brown bats and tri-colored bats) hibernating in the cave. Though northern long-eared bats fly outside of the hibernacula during the winter, they do not feed; hence the function of this behavior is not well understood (Whitaker and Hamilton 1998, p. 101). It has been suggested, however, that bat activity during winter could be due in part to disturbance by researchers (Whitaker and Mumford 2009, pp. 210-211).

Northern long-eared bats exhibit significant weight loss during hibernation. In southern Illinois, Pearson (1962, p. 30) found an average weight loss of 20 percent during hibernation in male northern long-eared bats, with individuals weighing an average of 6.6 g (0.2 ounces) prior to January 10, and those collected after that date weighing an average of 5.3 g (0.2 ounces). Whitaker and Hamilton (1998, p. 101) reported a weight loss of 41-43 percent over the hibernation period for northern long-eared bats in Indiana. In eastern Missouri, male northern long-eared bats lost an average of 3 g (0.1 ounces), or 36 percent, during the hibernation period (late October through March), and females lost an average of 2.7 g (0.1 ounces), or 31 percent (Caire

et al.

1979, p. 406).

Migration and Homing

While the northern long-eared bat is not considered a long-distance migratory species, short regional migratory movements between seasonal habitats (summer roosts and winter hibernacula) have been documented between 56 km (35 mi) and 89 km (55 mi) (Nagorsen and Brigham 1993 p. 88; Griffin 1940b, pp. 235, 236; Caire

et al.

1979, p. 404). Griffin (1940b, pp. 235, 236) reported that a banded male northern long-eared bat had traveled from one hibernaculum in Massachusetts to another in Connecticut over the 2-month period of February to April, a distance of 89 km (55 mi). The spring migration period typically runs from mid-March to mid-May (Caire

et al.

1979, p. 404; Easterla 1968, p. 770; Whitaker and Mumford 2009, p. 207); fall migration typically occurs between mid-August and mid-October.

Northern long-eared bats have shown a high degree of philopatry (tendency to return to the same location) for a hibernaculum (Pearson 1962), although they may not return to the same hibernaculum in successive seasons (Caceres and Barclay 2000). Banding studies in Ohio, Missouri, and Connecticut show return rates to hibernacula of 5.0 percent (Mills 1971, p. 625), 4.6 percent (Caire

et al.

1979, p. 404), and 36 percent (Griffin 1940a, p. 185), respectively. An experiment showed an individual bat returned to its home cave up to 32 km (20 mi) away after being removed 3 days prior (Stones and Branick 1969, p. 158).

Reproduction

Mating occurs from late July in northern regions to early October in southern regions and commences when males begin to aggregate around hibernacula and initiate copulation activity (Whitaker and Hamilton 1998, p. 101; Whitaker and Mumford 2009, p. 210; Caceres and Barclay 2000, p. 2; Amelon and Burhans 2006, p. 69). Copulation occasionally occurs again in the spring (Racey 1982, p. 73), and can occur during the winter as well (Kurta 2014, in litt.). Hibernating females store sperm until spring, exhibiting delayed fertilization (Racey 1979, p. 392; Caceres and Pybus 1997, p. 4). Ovulation takes place near the time of emergence from hibernation, followed by fertilization of a single egg, resulting in a single embryo (Cope and Humphrey 1972, p. 9; Caceres and Pybus 1997, p. 4; Caceres and Barclay 2000, p. 2); gestation is approximately 60 days, based on like species (Kurta 1995, p. 71). Males are generally reproductively inactive from April until late July, with testes enlarging in preparation for breeding in most males during August and September (Caire

et al.

1979, p. 407; Amelon and Burhans 2006, p. 69; Kurta 2013, in litt.).

Maternity colonies, consisting of females and young, are generally small, numbering from about 30 (Whitaker and Mumford 2009, p. 212) to 60 individuals (Caceres and Barclay 2000, p. 3); however, one group of 100 adult females was observed in Vermilion County, Indiana (Whitaker and Mumford 2009, p. 212). In West Virginia, maternity colonies in two studies had a range of 7 to 88 individuals (Owen

et al.

2002, p. 2) and 11 to 65 individuals, with a mean size of 31 (Menzel

et al.

2002, p. 110). Lacki and Schwierjohann (2001, p. 485) found that the number of bats within a given roost declined as the summer progressed. Pregnant females formed the largest aggregations (mean=26) and post-lactating females formed the smallest aggregation (mean=4). The largest overall reported colony size of 65 bats. Other studies have also found that the number of individuals roosting together in a given roost typically decreases from pregnancy to post-lactation (Foster and Kurta 1999, p. 667; Lacki and Schwierjohann 2001, p. 485; Garroway and Broders 2007, p. 962; Perry and Thill 2007, p. 224; Johnson

et al.

2012, p. 227). Female roost site selection, in terms of canopy cover and tree height, changes depending on reproductive stage; relative to pre- and post-lactation periods, lactating northern long-eared bats have been shown to roost higher in tall trees situated in areas of relatively less canopy cover and lower tree density (Garroway and Broders 2008, p. 91).

Adult females give birth to a single pup (Barbour and Davis 1969, p. 104). Birthing within the colony tends to be synchronous, with the majority of births occurring around the same time (Krochmal and Sparks 2007, p. 654). Parturition (birth) likely occurs in late May or early June (Caire

et al.

1979, p. 406; Easterla 1968, p. 770; Whitaker and Mumford 2009, p. 213), but may occur as late as July (Whitaker and Mumford 2009, p. 213). Broders

et al.

(2006, p. 1177) estimated a parturition date of July 20 in New Brunswick. Lactating and post-lactating females were observed in mid-June in Missouri (Caire

et al.

1979, p. 407), July in New Hampshire and Indiana (Sasse and Pekins 1996, p. 95; Whitaker and Mumford 2009, p. 213), and August in Nebraska (Benedict 2004, p. 235). Juvenile volancy (flight) often occurs by 21 days after birth (Krochmal and Sparks 2007, p. 651, Kunz 1971, p. 480) and has been documented as early as 18 days after birth (Krochmal and Sparks 2007, p. 651). Subadults were captured in late June in Missouri (Caire

et al.

1979, p. 407), early July in Iowa (Sasse and Pekins 1996, p. 95), and early August in Ohio (Mills 1971, p. 625).

Maximum lifespan for northern long-eared bats is estimated to be up to 18.5 years (Hall

et al.

1957, p. 407). Most mortality for northern long-eared bats and many other species of bats occurs during the juvenile stage (Caceres and Pybus 1997, p. 4).

Foraging Behavior

Northern long-eared bats are nocturnal foragers and use hawking (catching insects in flight) and gleaning (picking insects from surfaces) behaviors in conjunction with passive acoustic cues (Nagorsen and Brigham 1993, p. 88; Ratcliffe and Dawson 2003, p. 851). Observations of northern long-eared bats foraging on arachnids (spiders) (Feldhamer

et al.

2009, p. 49), presence of green plant material in their feces (Griffith and Gates 1985, p. 456), and non-flying prey in their stomach contents (Brack and Whitaker 2001, p. 207) suggest considerable gleaning behavior. The northern long-eared bat has a diverse diet including moths, flies, leafhoppers, caddisflies, and beetles (Nagorsen and Brigham 1993, p. 88; Brack and Whitaker 2001, p. 207; Griffith and Gates 1985, p. 452), with diet composition differing geographically and seasonally (Brack and Whitaker 2001, p. 208). Feldhamer

et al.

(2009, p. 49) noted close similarities of all

Myotis

diets in southern Illinois, while Griffith and Gates (1985, p. 454) found significant differences between the diets of northern long-eared bats and little brown bats. The most common insects found in the diets of northern long-eared bats are lepidopterans (moths) and coleopterans (beetles) (Brack and Whitaker 2001, p. 207; Lee and McCracken 2004, pp. 595-596; Feldhamer

et al.

2009, p. 45; Dodd

et al.

2012, p. 1122), with arachnids also being a common prey item (Feldhamer

et al.

2009, p. 45). Northern long-eared bats have the highest frequency call of any bat species in the Great Lakes area (Kurta 1995, p. 71). Gleaning allows this species to gain a foraging advantage for preying on moths because moths are less able to detect these high frequency echolocation calls (Faure

et al.

1993, p. 185).

Most foraging occurs above the understory, 1 to 3 m (3 to 10 ft) above the ground, but under the canopy (Nagorsen and Brigham 1993, p. 88) on forested hillsides and ridges, rather than along riparian areas (Brack and Whitaker 2001, p. 207; LaVal

et al.

1977, p. 594). This coincides with data indicating that mature forests are an important habitat type for foraging northern long-eared bats (Caceres and Pybus 1997, p. 2). Occasional foraging also takes place over small forest clearings and water, and along roads (van Zyll de Jong 1985, p. 94). Foraging patterns indicate a peak activity period within 5 hours after sunset followed by a secondary peak within 8 hours after sunset (Kunz 1973, pp. 18-19). Brack and Whitaker (2001, p. 207) did not find significant differences in the overall diet of northern long-eared bats between morning (3 a.m. to dawn) and evening (dusk to midnight) feedings; however there were some differences in the consumption of particular prey orders between morning and evening feedings. Additionally, no significant differences existed in dietary diversity values between age classes or sex groups (Brack and Whitaker 2001, p. 208).

Home Range

Northern long-eared bats exhibit site fidelity to their summer home range (Perry 2011, pp. 113-114; Johnson

et al.

2009a, p. 237; Jackson 2004, p. 87; Foster and Kurta 1999, p. 665). During this period, northern long-eared bats roost (Sasse and Pekins 1996, pp. 95-96; Owen

et al.

2002, p. 1; Perry and Thill 2007, pp. 224-225; Timpone

et al.

2010, p. 116) and forage (Owen

et al.

2003, pp. 354-355; Sheets 2010, pp. 3-4, 18; Tichenell

et al.

2011, p. 985; Dodd

et al.

2012, p. 1120) in forests. Their home ranges, which include both the foraging and roosting areas, may vary by sex. Broders

et al.

(2006, p. 1117) found home ranges of females (mean of 8.6 ha (21.3 acres)) to be larger than males (mean of 1.4 ha (3.5 acres)), though Lereculeur (2013, p. 20) found no difference between sexes at a study site in Tennessee. Also, Broders

et al.

(2006, p. 1117) and Henderson and Broders (2008, p. 958) found foraging areas (of either sex) to be six or more times larger than roosting areas. At sites in the Red River Gorge area of the Daniel Boone National Forest, Lacki

et al.

(2009, p. 1169) found female home range size to range from 19 to 172 ha (47 to 425 acres). Owen

et al.

(2003, p. 353) estimated average maternal home range size to be 65 ha (161 acres). Home range size of northern long-eared bats in this study site was small relative to other bat species, but this may be due to the study's timing (during the maternity period) and the small body size of northern long-eared bats (Owen

et al.

2003, pp. 354-355). The mean distance between roost trees and foraging areas of radio-tagged individuals in New Hampshire was 602 m (1,975 ft) with a range of 60 to 1,719 m (197 to 5,640 ft) (Sasse and Pekins 1996, p. 95). Work on Prince Edward Island by Henderson and

Broders (2008, p. 956) found female northern long-eared bats traveling approximately 1,100 m (3,609 ft) between roosting and foraging areas.

Summary of Factors Affecting the Species

Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species based on any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these factors is discussed below.

We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats to the northern long-eared bat. There are several factors presented below that affect the northern long-eared bat to a greater or lesser degree; however, we have found that no other threat is as severe and immediate to the northern long-eared bat's persistence as the disease, white-nose syndrome (WNS), discussed below under Factor C. WNS is currently the predominant threat to the species, and if WNS had not emerged or was not affecting the northern long-eared bat populations to the level that it has, we presume the species' would not be experiencing the dramatic declines that it has since WNS emerged. Therefore, although we have included brief discussions of other factors affecting the species, the focus of the discussion below is on WNS.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

Hibernation Habitat

Modifications to bat hibernacula, by erecting physical barriers (

e.g.,

doors, gates), to control cave and mine access can affect the microclimate of the subterranean habitat, and thus the ability of the cave or mine to support hibernating bats, including the northern long-eared bat. These well-documented effects on cave-hibernating bat species were discussed in the Service's Indiana Bat Draft Recovery Plan (Service 2007, pp. 71-74). Anthropogenic modifications to cave and mine entrances, such as the addition of restrictive gates or other structures intended to exclude humans, may not only alter flight characteristics and access (Spanjer and Fenton 2005, p. 1110), but may change airflow and alter internal microclimates of the caves and mines, eliminating their utility as hibernacula (Service 2007, p. 71). For example, Richter

et al.

(1993, p. 409) attributed the decline in the number of Indiana bats at Wyandotte Cave, Indiana (which harbors one of the largest known population of hibernating Indiana bats), to an increase in the cave's temperature resulting from restricted airflow caused by a stone wall erected at the cave's entrance. After the wall was removed, the number of Indiana bats increased markedly over the next 14 years (Richter

et al.

1993, p. 412; Brack

et al.

2003, p. 67). Similarly, northern long-eared bats were likely negatively impacted when the entrance to John Friend Cave in Maryland was filled with large rocks in 1981, which closed the only known access to the cave (Gates

et al.

1984, p. 166). We conclude, based on the need for specific hibernation requirements of any cave-hibernating bat, that alteration of hibernacula could result in adverse impacts to individual northern long-eared bats.

In addition to the direct access modifications to caves discussed above, debris buildup at entrances or on cave gates can also significantly modify the cave or mine site characteristics by restricting airflow and the course of natural water flow. Water flow restriction could lead to flooding, thus drowning hibernating bats (Amelon and Burhans 2006, p. 72). For example, in Minnesota, 5 of the 11 known northern long-eared bat hibernacula are subject to flooding, presenting a threat to hibernating bats (Nordquist 2012, pers. comm.). Flooding has been noted in hibernacula in other States within the range of the northern long-eared bat, but to a lesser degree. Although modifications to hibernacula can lead to mortality of northern long-eared bats, we do not conclude it has resulted in population-level effects.

Mining operations, mine passage collapse (subsidence), and mine reclamation activities can also affect bats and their hibernacula. Internal and external collapse of abandoned coal mines was identified as one of the primary threats to northern long-eared bat hibernacula at sites located within the New River Gorge National River and Gauley River National Recreation Area in West Virginia (Graham 2011, unpublished data). In States surveyed for effects to northern long-eared bats by hibernacula collapse, responses varied, with the following number of hibernacula in each State reported (not all States surveyed responded) as susceptible to collapse: 1 (of 7) in Maryland, 3 (of 11) in Minnesota, 1 (of 5) in New Hampshire, 4 (of 15) in North Carolina, 1 (of 2) in South Carolina, and 1 (of 13) in Vermont (Service 2011, unpublished data). Previous and current mining operations pose a direct threat to northern long-eared bat from mine collapse in parts of its range.

Before Federal and State cave protection laws were put in place, there were several reported instances where mines were closed while bats were hibernating, thereby entombing entire colonies (Tuttle and Taylor 1998, p. 8). For the northern long-eared bat, loss of potential winter habitat through mine closures has been noted as a concern in Virginia, although visual inspections of openings are typically conducted to determine whether gating is warranted (Reynolds 2011, unpublished data). In Nebraska, closing quarries, and specifically sealing quarries in Cass and Sapry Counties, is considered a potential threat to northern long-eared bats (Geluso 2011, unpublished data).

In general, threats to the integrity of bat hibernacula have decreased since the Indiana bat was listed as endangered in 1967, and since the implementation of Federal and State cave protection laws and abandoned mine reclamation programs. Increasing awareness about the importance of cave and mine microclimates to hibernating bats and regulation under the Act have helped to alleviate the destruction or modification of hibernation habitat, at least where the Indiana bat and gray bat (

Myotis grisescens

) are present (Service 2007, p. 74). The northern long-eared bat has likely benefited from the protections given to the Indiana bat and the gray bat and their winter habitat, in areas where its range overlaps with those species' ranges.

Disturbance of Hibernating Bats

Human disturbance of hibernating bats has long been considered a threat to cave-hibernating bat species like the northern long-eared bat, and is discussed in detail in the Service's Indiana Bat Draft Recovery Plan (Service 2007, pp. 80-85). The primary forms of human disturbance to hibernating bats results from cave commercialization (cave tours and other commercial uses of caves), recreational caving, vandalism, and research-related activities (Service 2007, p. 80). Arousal during hibernation causes the greatest amount of energy depletion in

hibernating bats (Thomas

et al.

1990, p. 477). Human disturbance at hibernacula, specifically non-tactile disturbance such as changes in light and sound, can cause bats to arouse more frequently, causing premature energy store depletion and starvation, as well as increased tactile disturbance amongst bats (Thomas 1995, p. 944; Speakman

et al.

1991, p. 1103), leading to marked reductions in bat populations (Tuttle 1979, p. 3). Prior to the outbreak of WNS, Amelon and Burhans (2006, p. 73) indicated that “the widespread recreational use of caves and indirect or direct disturbance by humans during the hibernation period pose the greatest known threat to this species (northern long-eared bat).” Olson

et al.

(2011, p. 228), hypothesized that an increase in the hibernating bat population (including northern long-eared bats) was related to decreased visits by recreational users and researchers at Cadomin Cave in Alberta, Canada. Bilecki (2003, p. 55) states that the reduction of four species of bats, including the northern long-eared bat, was “directly related to high human use and abuse” of a cave. Disturbance during hibernation could cause movements within or between caves (Beer 1955, p. 244).

Of 14 States that assessed the possibility of human disturbance at bat hibernacula within the range of the northern long-eared bat, 13 identified at least 1 known hibernacula as potentially impacted by human disturbance (Service 2012, unpublished data). Eight of these 14 States (Arkansas, Kentucky, Maine, Minnesota, New Hampshire, North Carolina, South Carolina, and Vermont) indicated the potential for human disturbance at over 50 percent of the known hibernacula in that State. Nearly all States without WNS identified human disturbance as the primary threat to hibernating bats, and all others (including WNS-positive States) noted human disturbance as the next greatest threat after WNS or of significant concern (Service 2012, unpublished data).

The threat of commercial use of caves and mines during the hibernation period has decreased at many sites known to harbor Indiana bats, and we conclude that this also applies to northern long-eared bats. However, effects from recreational caving are more difficult to assess. In addition to unintended effects of commercial and recreational caving, intentional killing of bats in caves by shooting, burning, and clubbing has been documented (Tuttle 1979, pp. 4, 8). Intentional killing of northern long-eared bats has been documented at a small percentage of hibernacula (

e.g.,

one case of shooting disturbance in Maryland and one case of bat torching in Massachusetts where approximately 100 bats (northern long-eared bats and other species) were killed) (Service, unpublished data), but we do not have evidence that this is happening on a large enough scale to have population-level effects.

In summary, while there are isolated incidents of previous disturbance to northern long-eared bats from both intentional disturbance and recreational use of caves and mines, we conclude that there is no evidence suggesting that this threat in itself has led to population-level declines.

Summer Habitat

As discussed in detail in the Background (

Biology,

“I. Summer Roost Characteristics”) section, above, northern long-eared bats require forest for roosting, raising young, foraging, and commuting between roosting and foraging habitat. Northern long-eared bats will also roost in manmade structures, to a lesser extent. The two common causes of loss or modification of habitat are conversion of forest for other land use and forest modification.

I. Forest Conversion

Forest conversion is the loss of forest to another land cover type (

e.g.,

grassland, cropland, development) and may result in: Loss of suitable roosting or foraging habitat; fragmentation of remaining forest patches, leading to longer flights between suitable roosting and foraging habitat; removal of (fragmenting colonies/networks) travel corridors; and direct injury or mortality (during active season clearing). While forest conversion may occur throughout all States within the species' range, impacts to the northern long-eared bat and their habitat typically occur at a more local-scale

(i.e.,

individuals and potentially colonies).

The USFS (2014, p. 7) summarized U.S. forest trends and found a decline from 1850 to the early 1900s, and a general leveling off since that time; therefore, conversion from forest to other land cover types has been fairly stable with conversion to forest (cropland reversion/plantings). For example, according to the U.S. Forest Service's Forest Inventory and Analysis, the amount of forested land within the 37 States and the District of Columbia of the northern long-eared bat's range increased from 414,297,531 acres in 2004 and 2005, to 423,585,498 acres in 2013 (Association of Fish and Wildlife Agencies 2014, in litt; Miles 2014,

http://apps.fs.fed.us/Evalidator/evalidator.jsp

). However, between 2001 and 2006, there was a net loss of 1.2 percent of forest across the United States with most losses in the Southeast and West, and a net loss of interior forest (a forest parcel embedded in a 40-acre landscape that has at least 90 percent forest land cover) of 4.3 percent (USFS 2014, p. 18) throughout the continental United States, which increased forest fragmentation and smaller remaining forest patches. There is some evidence that northern long-eared bats have an affinity for less fragmented habitat (interior forest) (Broders

et al.

2006, p. 1181; Henderson

et al.

2008, p. 1825). Also, forest ownership varies widely across the species' range in the United States. Private lands may carry with them a higher risk for conversion than do public forests, a factor that must be considered when assessing risk of forest conversion now and in the future. Private land ownership is approximately 81 percent in the East and 30 percent in the West (USFS 2014, p. 15).

Some of the highest rates of development in the conterminous United States are occurring within the range of the northern long-eared bat (Brown

et al.

2005, p. 1856), and contribute to loss of forest habitat. The 2010 Resources Planning Act (RPA) Assessment (USFS 2012) summarized findings about the status, trends, and projected future of U.S. forests. This assessment was influenced by a set of scenarios with varying assumptions with regard to global and U.S. population, economic growth, climate change, wood energy consumption, and land use change from 2010 to 2060. It projects forest losses of 6.5-13.8 million ha (16-34 million acres or 4-8 percent of 2007 forest area) across the conterminous United States, and forest loss is expected to be concentrated in the southern United States, with losses of 3.6-8.5 million ha (9-21 million acres) (USFS 2012, p. 12).

Wind energy development continues to increase throughout the northern long-eared bat's range. Iowa, Illinois, Oklahoma, Minnesota, Kansas, and New York are amongst the top 10 States for wind energy capacity (installed projects) in the United States (American Wind Energy Association (AWEA) 2013, unpaginated). If projects are sited in forested habitats, effects from wind energy development may include tree-clearings associated with turbine placement, road construction, turbine lay-down areas, transmission lines, and substations. See

Factor E. Other

Natural or Manmade Factors Affecting Its Continued Existence for a Discussion on Effects to Bats From the Operation of Wind Turbines

Surface coal mining is common in the central Appalachian region, which includes portions of Pennsylvania, West Virginia, Virginia, Kentucky, Ohio, and Tennessee, and is one of the major drivers of land cover change in the region (Sayler 2008, unpaginated). Surface coal mining may also destroy forest habitat in parts of the Illinois Basin in southwest Indiana, western Kentucky, and Illinois (King 2013, pers. comm.).

Natural gas extraction is expanding across the United States, particularly throughout the range of the northern long-eared bat. Natural gas extraction involves fracturing rock formations using highly pressurized water and other various chemicals (Hein 2012, p. 1). Natural gas extraction and transmission, particularly across the Marcellus Shale region, which includes large portions of New York, Pennsylvania, Ohio, and West Virginia, is expected to expand over the coming years. In Pennsylvania, for example, nearly 2,000 Marcellus natural gas wells have already been drilled or permitted, and if development trends continue, as many as 60,000 more could be built by 2030 (Johnson 2010, pp. 8, 13). Habitat necessary for establishing maternity colonies and foraging may be lost and degraded due to the practice of forest clearing for well pads and associated infrastructures (

e.g.,

roads, pipelines, and water impoundments). These actions could decrease the amount of suitable interior forest habitat available to northern long-eared bats.

There are a variety of reasons forests are being converted (

e.g.,

urban development, energy production, and transmission) within the range of the northern long-eared bat. Impacts to northern long-eared bats from loss of forest vary depending on the timing, location, and extent of the removal. While bats can sometimes flee during tree removal, removal of occupied roosts (during spring through fall) is likely to result in direct injury or mortality to some northern long-eared bats. This is particularly likely during cool spring months (when bats enter torpor) and if flightless pups or inexperienced flying juveniles are also present. Removal of forest outside of northern long-eared bat summer home range, or away from hibernacula, would not likely directly impact the species. However, removal of forest within a summer home range (regardless of when it is removed) may negatively impact the species, depending on the extent of removal and the amount of remaining suitable roosting and foraging habitat.

Some portions of the northern long-eared bat's range are more forested than others. In areas with little forest or highly fragmented forests (

e.g.,

western U.S. edge of the range, central Midwestern states; see Figure 1, above), impact of forest loss would be disproportionately greater than similar-sized losses in heavily forested areas (

e.g.,

Appalachians and northern forests). Also, the impact of habitat loss within a northern long-eared bat's home range is expected to vary depending on the scope of removal. Northern long-eared bats are flexible in which tree species they select as roosts, and roost trees are an ephemeral resource; therefore, the species likely can tolerate some loss of roosts, provided suitable alternative roosts are available. Silvis

et al.

(2014, pp. 283-290) modeled roost loss of northern long-eared bats, and Silvis

et al.

(2015, pp. 1-17) removed known northern long-eared bat roosts during the winter in the field to determine how this would impact the species. Once removals totaled 20-30 percent of known roosts, a single maternity colony network started showing patterns of break-up. Sociality is hypothesized to increase reproductive success (Silvis

et al.

2014, p. 283), and smaller colonies would be expected to have reduced reproductive success.

Longer flights to find alternative suitable habitat and colonial disruption may result from removal of roosting or foraging habitat. Northern long-eared bats emerge from hibernation with their lowest annual fat reserves, and return to their summer home ranges. Because northern long-eared bats have summer home range fidelity (Foster and Kurta 1999, p. 665; Patriquin

et al.

2010, p. 908; Broders

et al.

2013, p. 1180), loss or alteration of forest habitat may put additional stress on females when returning to summer roost or foraging areas after hibernation. Females (often pregnant) have limited energy reserves available for use if forced to seek out new roosts or foraging areas. Hibernation and reproduction are the most energetically demanding periods for temperate-zone bats, including the northern long-eared bat (Broders

et al.

2013, p. 1174). Bats may reduce metabolic costs of foraging by concentrating efforts in areas of known high prey profitability, a benefit that could result from the bat's local roosting and home range knowledge and site fidelity (Broders

et al.

2013, p. 1181). Cool spring temperatures provide an additional energetic demand, as bats need to stay sufficiently warm or enter torpor. Entering torpor comes at a cost of delayed parturition; bats born earlier in the year have a greater chance of surviving their first winter and breeding in their first year of life (Frick

et al.

2010b, p. 133). Delayed parturition may also be costly because young of the year and adult females would have less time to prepare for hibernation (Broders

et al.

2013, p. 1180). Female northern long-eared bats typically roost colonially, with their largest population counts occurring in the spring (Foster and Kurta 1999, p. 667), presumably as one way to reduce thermal costs for individual bats (Foster and Kurta 1999, p. 667). Therefore, similar to other temperate bats, northern long-eared bats have multiple high metabolic demands (particularly in spring), and must have sufficient suitable roosting and foraging habitat available in relatively close proximity to allow for successful reproduction.

In summary, U.S. forest area trends have remained relatively stable with some geographic regions facing more conversion than others in the recent past. In the future, forest conversion is expected to increase, whether from commercial or residential development, energy production, or other pressures on forest lands. While monitoring efforts for impacts to northern long-eared bats from forest conversion did not often occur in the past, we expect that impacts likely occurred, but the species appears to have been resilient to these impacts prior to the emergence of WNS. In areas where WNS is present, there are additional energetic demands for northern long-eared bats. For example, WNS-affected bats have less fat reserves than non-WNS-affected bats when they emerge from hibernation (Reeder

et al.

2012, p. 8; Warnecke

et al.

2012, p. 7001) and have wing damage (Meteyer

et al.

2009, p. 412; Reichard and Kunz 2009, p. 458) that makes migration and foraging more challenging. Females that survive the migration to their summer habitat must partition energy resources between foraging, keeping warm, successful pregnancy and pup-rearing, and healing. Current and future forest conversion may have negative additive impacts where the species has been impacted by WNS. Impacts from forest conversion to individuals or colonies would be expected to range from indirect impact (

e.g.,

minor amounts of forest removal in areas outside northern long-eared bat summer home ranges or away from hibernacula) to minor (

e.g.,

largely forested areas, areas with robust northern long-eared bat populations) to significant (

e.g.,

removal of a large percentage of summer home range,

highly fragmented landscapes, areas with WNS impacts).

II. Forest Management

Unlike forest conversion, forest management maintains forest habitat on the landscape, and the impacts from management activities are for the most part considered temporary in nature. Forest management includes multiple practices, and this section specifically addresses timber harvest. Timber harvesting includes a wide variety of practices from selected harvest of individual trees to clearcutting. Impacts from forest management would be expected to range from positive (

e.g.,

maintaining or increasing suitable roosting and foraging habitat within northern long-eared bat home ranges) to neutral (

e.g.,

minor amounts forest removal, areas outside northern long-eared bat summer home ranges or away from hibernacula) to negative (

e.g.,

death of adult females or pups or both).

The best available data indicate that the northern long-eared bat shows a varied degree of sensitivity to timber harvesting practices. For example, Menzel

et al.

(2002, p. 112) found northern long-eared bats roosting in intensively managed stands in West Virginia; indicating that there were sufficient suitable roosts (primarily snags) remaining for their use. At the same study site, Owen

et al.

(2002, p. 4) concluded that northern long-eared bats roosted in areas with abundant snags, and that in intensively managed forests in the central Appalachians, roost availability was not a limiting factor. Northern long-eared bats often chose black locust and black cherry as roost trees, which were quite abundant and often regenerate quickly after disturbance (

e.g.,

timber harvest). Similarly, Perry and Thill (2007, p. 222) tracked northern long-eared bats in central Arkansas and found roosts were located in eight forest classes with 89 percent in three classes of mixed pine-hardwood forest. The three classes of mixed pine-hardwood forest that supported the majority of the roosts were partially harvested or thinned, unharvested (50-99 years old), and group selection harvest (Perry and Thill 2007, pp. 223-224).

Certain levels of timber harvest may result in canopy openings, which could result in more rapid development of bat young. In central Arkansas, Perry and Thill (2007, pp. 223-224) found female bat roosts were more often located in areas with partial harvesting than males, with more male roosts (42 percent) in unharvested stands than female roosts (24 percent). They postulated that females roosted in relatively more open forest conditions because they may receive greater solar radiation, which may increase developmental rates of young or permit young bats a greater opportunity to conduct successful initial flights (Perry and Thill 2007, p. 224). Cryan

et al.

(2001, p. 49) found several reproductive and nonreproductive female northern long-eared bat roost areas in recently harvested (less than 5 years) stands in the Black Hills of South Dakota in which snags and small stems (dbh of 2 to 6 inches (5 to 15 cm)) were the only trees left standing; however, the largest colony (n = 41) was found in a mature forest stand that had not been harvested in more than 50 years.

Forest size and continuity are also factors that define the quality of habitat for roost sites for northern long-eared bats. Lacki and Schwierjohann (2001, p. 487) stated that silvicultural practices could meet both male and female roosting requirements by maintaining large-diameter snags, while allowing for regeneration of forests. Henderson

et al.

(2008, p. 1825) also found that forest fragmentation effects northern long-eared bats at different scales based on sex; females require a larger unfragmented area with a large number of suitable roost trees to support a colony, whereas males are able to use smaller, more fragmented areas. Henderson and Broders (2008, pp. 959-960) examined how female northern long-eared bats use the forest-agricultural landscape on Prince Edward Island, Canada, and found that bats were limited in their mobility and activities are constrained when suitable forest is limited. However, they also found that bats in a relatively fragmented area used a building for colony roosting, which suggests an alternative for a colony to persist in an area with fewer available roost trees.

In addition to impacts on roost sites, we consider effects of forest management practices on foraging and traveling behaviors of northern long-eared bats. In southeastern Missouri, the northern long-eared bat showed a preference for contiguous tracts of forest cover (rather than fragmented or wide open landscapes) for foraging or traveling, and different forest types interspersed on the landscape increased likelihood of occupancy (Yates and Muzika 2006, p. 1245). Similarly, in West Virginia, female northern long-eared bats spent most of their time foraging or travelling in intact forest, diameter-limit harvests (70-90 year-old stands with 30-40 percent of basal area removed in the past 10 years), and road corridors, with no use of deferment harvests (similar to clearcutting) (Owen

et al.

2003, p. 355). When comparing use and availability of habitats, northern long-eared bats preferred diameter-limit harvests and forest roads. In Alberta, Canada, northern long-eared bats avoided the center of clearcuts and foraged more in intact forest than expected (Patriquin and Barclay 2003, p. 654). On Prince Edward Island, Canada, female northern long-eared bats preferred open areas less than forested areas, with foraging areas centered along forest-covered creeks (Henderson and Broders 2008, pp. 956-958). In mature forests in South Carolina, 10 of the 11 stands in which northern long-eared bats were detected were mature stands (Loeb and O'Keefe 2006, p. 1215). Within those mature stands, northern long-eared bats were more likely to be recorded at points with sparse or medium vegetation rather than points with dense vegetation, suggesting that some natural gaps within mature forests can provide good foraging habitat for northern long-eared bats (Loeb and O'Keefe 2006, pp. 1215-1217). However, in southwestern North Carolina, Loeb and O'Keefe (2011, p. 175) found that northern long-eared bats rarely used forest openings, but often used roads. Forest trails and roads may provide small gaps for foraging and cover from predators (Loeb and O'Keefe 2011, p. 175). In general, northern long-eared bats prefer intact mixed-type forests with small gaps (

i.e.,

forest trails, small roads, or forest-covered creeks) in forest with sparse or medium vegetation for forage and travel rather than fragmented habitat or areas that have been clearcut.

Impacts to northern long-eared bats from forest management would be expected to vary depending on the timing of removal, location (within or outside northern long-eared bat home range), and extent of removal. While bats can flee during tree removal, removal of occupied roosts (during spring through fall) is likely to result in direct injury or mortality to some percentage of northern long-eared bats. This percentage would be expected to be greater if flightless pups or inexperienced flying juveniles were also present. Forest management outside of northern long-eared bat summer home ranges or away from hibernacula would not be expected to result in impacts to this species. However, forest management within a summer home range (regardless of when it is removed) may result in impacts to this species, depending on the extent of removal and amount of remaining suitable roosting and foraging habitat.

Unlike forest conversion, forest management is not usually expected to

result in a permanent loss of suitable roosting or foraging habitat for northern long-eared bats. On the contrary, forest management is expected to maintain a forest over the long term for the species. However, localized long-term reductions in suitable roosting and/or foraging habitat can occur from various forest practices (

e.g.,

clearcuts). As stated above, northern long-eared bats have been found in forests that have been managed to varying degrees, and as long as there is sufficient suitable roosting and foraging habitat within their home range and travel corridors between those areas, we would expect northern long-eared bat colonies to continue to occur in managed landscapes. However, in areas with WNS, we believe northern long-eared bats are likely less resilient to stressors and maternity colonies are smaller. Given the low inherent reproductive potential of northern long-eared bats (max of one pup per female), death of adult females or pups or both during tree felling reduces the long-term viability of those colonies.

Conservation Efforts To Reduce Habitat Destruction, Modification, or Curtailment of Its Range

Although there are various forms of habitat destruction and disturbance that present potential adverse effects to the northern long-eared bat, they are not considered the predominant threat to the species. Even if all habitat-related stressors were eliminated or minimized, the significant effects of WNS on the northern long-eared bat would remain. Therefore, below we present a few examples, but not a comprehensive list, of conservation efforts that have been undertaken to lessen effects from habitat destruction or disturbance to the northern long-eared bat.

Direct protection of caves and mines can be accomplished through installation of bat-friendly gates that allow passage of bats while reducing disturbance from human entry as well as changes to the cave microclimate from air restrictions. One of the threats to bats in Michigan is the closure of unsafe mines in such a way that bats are trapped within or excluded; however, there have been efforts by the Michigan Department of Natural Resources and others to work with landowners who have open mines to encourage them to install bat-friendly gates to close mines to humans, but allow access to bats (Hoving 2011, unpublished data). The NPS has proactively taken steps to minimize effects to underground bat habitat resulting from vandalism, recreational activities, and abandoned mine closures (Plumb and Budde 2011, unpublished data). In addition, the NPS is properly gating abandoned coal mine entrances, using a “bat-friendly” design, as funding permits (Graham 2011, unpublished data). All known hibernacula within national grasslands and forestlands of the Rocky Mountain Region of the USFS are closed during the winter hibernation period, primarily due to the threat of WNS, although this will reduce disturbance to bats in general inhabiting these hibernacula (USFS 2013, unpaginated). Because of concern over the importance of bat roosts, including hibernacula, the American Society of Mammalogists developed guidelines for protection of roosts, many of which have been adopted by government agencies and special interest groups (Sheffield

et al.

1992, p. 707).

Many States are also taking a proactive stance to conserve and restore forest and riparian habitats with specific focus on maintaining forest patches and connectivity. For example, Montana is developing best management practices for riparian habitat protection. Other States have established habitat protection buffers around known Indiana bat hibernacula that will also serve to benefit northern long-eared bat by maintaining sufficient quality and quantity of swarming habitat. Some States have also limited tree-clearing activities to the winter, as a measure that would protect maternity colonies and non-volant pups during summer months. Many States are undertaking research and monitoring efforts to gain more information about habitat needs of and use by northern long-eared bat.

Summary of the Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

We have identified several potential threats to the northern long-eared bat due to impacts to their winter and summer habitats. Winter habitat may be impacted by both human and non-human modification of hibernacula, particularly damaging is the altering or closing of hibernacula entrances. These modifications can lead to a partial or complete loss of utility as hibernacula. Humans can also disturb hibernating bats, either directly or indirectly, potentially resulting in an increase in energy consuming arousal bouts during hibernation (Thomas 1995, pp. 940-945; Johnson

et al.

1998, pp. 255-260). Human disturbance at hibernacula has been identified by many States as the next greatest threat after WNS.

During the summer, northern long-eared bat habitat loss is primarily due to forest conversion and forest management. Throughout the range of northern long-eared bats, forest conversion is expected to increase due to commercial and urban development, energy production and transmission, and natural changes. Forest conversion can result in a myriad of effects to the species, including direct loss of habitat, fragmentation of remaining habitat, and direct injury or mortality. Forest management activities, unlike forest conversion, typically result in temporary (non-permanent) impacts to northern long-eared bat summer habitat. The impact of management activities may be positive, neutral, or negative to the northern long-eared bat depending on scale, the management practice, and timing. However, these potential impacts can be greatly reduced with the use of measures that avoid or minimize effects to bats and their habitat. Potential benefits to the species from forest management practices include keeping forest on the landscape and creation and management of roosting and foraging habitat (from some forest management practices).

Many activities continue to pose a threat to the summer and winter habitats of northern long-eared bats. While, these activities alone were unlikely to have significant, population-level effects, there is now likely a cumulative effect on the species in portions of range that have been impacted by WNS. Also, there have been numerous conservation efforts directed at lessening the effects of habitat destruction or disturbance on the species, including cross-State and cross-agency collaboration on habitat restoration and hibernacula protection.

Factor B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

There are very few records of the northern long-eared bat being collected specifically for commercial, recreational, scientific, or educational purposes, and thus we do not consider such collection activities to pose a threat to the species. Disturbance of hibernating bats as a result of recreational use and scientific research activities in hibernacula is discussed under Factor A.

Factor C. Disease or Predation

Disease

I. White-Nose Syndrome

White-nose syndrome (WNS) is an emerging infectious wildlife disease that poses a considerable threat to hibernating bat species throughout North America (Service 2011, p. 1). WNS is responsible for unprecedented mortality of insectivorous bats in

eastern North America (Blehert

et al.

2009, p. 227; Turner

et al.

2011, pp. 13, 22). The first evidence of the disease (a photo of bats with fungus) was documented at Howes Cave in Schoharie County, New York, 32 mi (52 km) west of Albany, on February 16, 2006, but WNS was not actually discovered until January 2007, when it was found at four additional caves around Schoharie County (Blehert

et al.

2009, p. 227). Since that time, WNS has spread rapidly throughout the Northeast, Southeast, Midwest, and eastern Canada. As of February 2015, WNS has been confirmed (meaning one or more bats in the State have been analyzed and confirmed with the disease) in 25 States (Alabama, Arkansas, Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Vermont, Virginia, West Virginia, and Wisconsin) and 5 Canadian provinces (New Brunswick, Nova Scotia, Ontario, Prince Edward Island, and Quebec). Although WNS has not been confirmed in Rhode Island (2 known hibernacula) or the District of Columbia (no known hibernacula), their size and proximity to heavily impacted WNS-confirmed States make it reasonable to conclude that bat populations are also affected by WNS there. Three additional States (Iowa, Minnesota, and Mississippi) are considered suspect for WNS based on the detection of the causative fungus, Pd (Lorch

et al.

2011, pp. 376-379; Muller

et al.

2013, pp. 253-259), on bats within those States, but no mortality or other signs of the disease have been documented at those locations as of December 2014. Evidence suggestive of the presence of Pd on one bat in Oklahoma was recently reassessed, and it was concluded that those initial findings are no longer supported (United States Geologic Survey (USGS) 2014, p. 1). Therefore, Oklahoma is no longer considered a suspect (meaning Pd confirmed) State for WNS. Table 1 (below) provides a summary of the States in which WNS is currently present.

State or district

WNS present?

First winter WNS confirmed

Documented WNS mortality in bats

Alabama

Yes

2011-2012

Yes.

Arkansas

Yes

2013-2014

Yes.

Connecticut

Yes

2007-2008

Yes.

District of Columbia

Unknown.

Delaware

Yes

2011-2012

Yes.

Georgia

Yes

2012-2013

Yes.

Illinois

Yes

2012-2013

Yes.

Indiana

Yes

2010-2011

Yes.

Iowa

Pd

Pd only (2011-2012)

No.

Kansas

No.

Kentucky

Yes

2010-2011

Yes.

Louisiana

No.

Maine

Yes

2010-2011

Yes.

Maryland

Yes

2009-2010

Yes.

Massachusetts

Yes

2007-2008

Yes.

Michigan

Yes

2013-2014

Yes.

Minnesota

Pd

Pd only (2011-2012)

No.

Mississippi

Pd

Pd only (2013-2014)

No.

Missouri

Yes

2011-2012

Yes.

Montana

No.

Nebraska

No.

New Hampshire

Yes

2008-2009

Yes.

New Jersey

Yes

2008-2009

Yes.

New York

Yes

2006-2007

Yes.

North Carolina

Yes

2010-2011

Yes.

North Dakota

No.

Oklahoma

No.

Ohio

Yes

2010-2011

Yes.

Pennsylvania

Yes

2008-2009

Yes.

Rhode Island

Unknown.

South Carolina

Yes

2012-2013

No.

South Dakota

No.

Tennessee

Yes

2009-2010

Yes.

Vermont

Yes

2007-2008

Yes.

Virginia

Yes

2008-2009

Yes.

West Virginia

Yes

2008-2009

Yes.

Wisconsin

Yes

2013-2014

Yes.

Wyoming

No.

Seven species of North American hibernating bats have been confirmed with WNS to date: big brown bat, gray bat, eastern small-footed bat, little brown bat, northern long-eared bat, Indiana bat, and tricolored bat. The effect of WNS appears to vary greatly by species, with several species exhibiting high mortality and others showing low or no appreciable population-level effects (Turner

et al.

2011, p. 13). The fungus that causes WNS has been detected on five additional species, but with no evidence of the infection characteristic of the disease; these include Rafinesque's big-eared bat (

Corynorhinus rafinesquii

), Virginia big-eared bat (

C. townsendii virginianus

), silver-haired bat (

Lasionycteris noctivagans

), eastern red bat (

Lasiurus borealis

), and southeastern bat (

Myotis austroriparius

).

The impacts of WNS on North American bat populations have been

substantial. Service and State biologists estimate that at least 5.7 million to 6.7 million bats of several species have died from WNS (Service 2012, p. 1). Dzal

et al.

(2011, p. 393) documented a 78 percent decline in the summer activity of little brown bats in New York State, coinciding with the arrival and spread of WNS, suggesting large-scale population effects. Turner

et al.

(2011, p. 22) reported an 88 percent decline in the number of all hibernating bats at 42 sites across New York, Pennsylvania, Vermont, Virginia, and West Virginia. Furthermore, Frick

et al.

(2010a, p. 681) concluded that the little brown bat, formerly the most common bat in the northeastern United States, is undergoing catastrophic declines in the region due to WNS, and is at risk of regional extirpation in the near future. Similarly, Thogmartin

et al.

(2013, p. 171) predicted that WNS is likely to extirpate the federally endangered Indiana bat over large parts of its range. While recent models by Ingersoll

et al.

(2013, p. 8) have raised some questions about the status of bat populations prior to the arrival of WNS, the empirical evidence from surveys of six species of hibernating bats in New York State, revealed populations that were likely stable or increasing prior to the emergence of WNS (Service 2011, p. 1). Subsequent to the emergence of WNS, decreases in some species of bats at affected hibernacula have ranged from 30 to 100 percent (Frick

et al.

2010a, p. 680; Turner

et al.

2011, pp. 16-19, 22).

The pattern of spread of WNS has generally followed predictable trajectories along recognized migratory pathways and overlapping summer ranges of hibernating bat species, with some exception. The range expansion of WNS and Pd has not only been limited to known migratory movements of bats. Kunz and Reichard (2010, p. 12) assert that WNS is spread and transmitted mainly through bat-to-bat contact; however, evidence suggests that fungal spores can be transmitted by humans (USGS National Wildlife Health Center (NWHC), Wildlife Health Bulletin 2011-05, unpaginated), and bats can also become infected by coming into contact with contaminated cave substrate (Darling and Hicks 2012, pers. comm.).

White-nose syndrome is caused by the psychrophilic (cold-loving) fungus Pd, which is likely exotic to North America, and only recently arrived on the continent (Puechmaille

et al.

2011, p. 8; Foster, pers. comm.; Warnecke

et al.

2012, p. 7001). The fungus grows on and within exposed soft tissues of hibernating bats (Lorch

et al.

2011, p. 376; Gargas

et al.

2009, pp. 147-154), and the resulting mycelium (vegetative part of fungus) is the white filamentous growth visible on the muzzle, ears, or flight membranes (wings and tail) of affected bats that is characteristic of WNS. Epidermal (skin) erosions that are filled with fungal hyphae (branching, filamentous structures of fungi) are the diagnostic standard for WNS (Blehert

et al.

2009, p. 227; Meteyer 2009, p. 412). Pd grows optimally at temperatures from 5 to 16 °C (41 to 61 °F), the same temperature range at which North American bats typically hibernate (Blehert

et al.

2009, p. 227; Verant

et al.

2012, p. 4). The temperature in caves that serve as bat hibernacula ranges from 2 to 14 °C (36 to 57 °F), permitting year-round persistence and growth of the fungus on cave substrates, allowing such hibernacula to serve as a reservoir for maintaining the fungus through summer months in the absence of bats (Blehert

et al.

2009, p. 227; Reynolds

et al.

2015, unpaginated). Growth is relatively slow at optimal temperatures (5 to 16 °C (41 to 61 °F)), and no growth occurs at temperatures above 21.4 °C (75 °F) (Blehert

et al.

2009, p. 227; Verant

et al.

2012, pp. 4, 6). Although Pd does not grow above 21.4 °C, it is known to remain viable for extended periods of time above that temperature (Lorch

et al.

2013, p. 237; Hoyt

et al.

2014, pp. 2-3). Declines in Indiana bats have been greater under more humid conditions, suggesting that growth of the fungus and either intensity or prevalence of infections are higher in more humid conditions (Langwig

et al.

2012, p. 1055). However, the effect of humidity on impacts of WNS in bat populations may vary among species. Furthermore, fungal load and prevalence varies among species in WNS-infected sites (Langwig

et al.

2015, p. 4).

Although Pd has been isolated from numerous bat species in Europe, it is hypothesized that these species have evolved in the presence of the fungus (Wibbelt

et al.

2010, p. 1241). Pikula

et al.

(2012, p. 210) confirmed that bats found dead in the Czech Republic exhibited lesions consistent with WNS infection; however, the authors also stated that the lesions were not believed to have contributed to the cause of death for those individuals. In all, there are now 12 European bat species, including one Rhinolophid in the sub-order Megachiroptera, that have been confirmed with the WNS disease (Zukal

et al.

2014, p. 8) (based on the case definitions established in North America (USGS, NWHC 2014, unpaginated)), although no mortality has been documented to date in Europe. This point illustrates the fact that Pd is capable of infecting a wide variety of bat hosts across a large spatial scale.

Bats affected by WNS are characterized by some or all of the following signs: (1) Excessive or unexplained mortality at or near the hibernaculum; (2) visible fungal growth on wing and tail membranes, the muzzle, or the ears of live or recently dead bats; (3) abnormal behaviors including conspicuous daytime activity outside of the hibernaculum, shifts of large numbers to the cold areas near the entrance or elsewhere in the hibernaculum, and decreased arousal with human disturbance inside hibernaculum (torpid bats responding to noise and vibrations in the cave); (4) moderate to severe wing damage in nontorpid bats; and (5) and depleted fat reserves by mid-winter (USGS, NWHC 2012, p. 1; Service 2011, p. 2). Although the exact process or processes by which WNS leads to death remains unconfirmed, we do know that the fungal infection is responsible, and it is possible that reduced immune function during torpor compromises the ability of hibernating bats to combat the infection (Bouma

et al.

2010, p. 623; Moore

et al.

2011, p. 10; Moore

et al.

2013, pp. 6-7; Reeder

et al.

2012, p. 8; Johnson

et al.

2014, unpaginated). It has also been hypothesized that immune reconstitution inflammatory syndrome (IRIS) causes mortality when systemic Pd-infections established during torpor initiate a massive inflammatory response when the infected bat emerges from hibernation (Meteyer

et al.

2012, pp. 585, 587).

No information was known about Pd and WNS prior to 2007. Early working hypotheses demonstrated that it was not known whether WNS-affected bats before the hibernation season began or if bats arrived at hibernacula sites unaffected and entered hibernation with sufficient fat stores (WNS Science Strategy Group 2008, p. 7). Hibernating bats rely on stored fats to survive winter months, when insect prey is not available. In a related study, 12 of 14 bats (10 little brown bats, 1 big-brown bat, and 1 tri-colored bat) had appreciable degree of fat stores, even though they were infected with WNS and were on the lower end of the normal range of body weight (Courtin

et al.

2010, p. 214). Further research has lead scientists to suggest that bats are capable of clearing fungal infections during the summer in some areas, and are likely re-infected with Pd when they return to swarming sites or hibernacula in the fall (Langwig

et al.

2015, p. 6). However, Dobony (2014, pers. comm.) noted the presence of viable Pd in a maternity roost throughout summer

months, indicating that in some situations bats can be exposed to the fungus year-round. Boyles and Willis (2010, pp. 92-98) hypothesized that infection by Pd alters the normal arousal cycles of hibernating bats, particularly by increasing arousal frequency, duration, or both. In fact, Reeder

et al.

(2012, p. 5) and Warnecke

et al.

(2012, p. 2) observed an increase in arousal frequency in laboratory studies of hibernating bats infected with Pd. A disruption of this torpor-arousal cycle could cause bats to metabolize fat reserves too quickly, thereby leading to starvation (Warnecke

et al.

2012, p. 4). The root cause of these

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