USE OF UNDERGROUND FACILITIES BY BATS AT THE HANFORD SITE IN SHRUB-STEPPE HABITATS IN WASHINGTON JONATHAN GUY LUCAS

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1 USE OF UNDERGROUND FACILITIES BY BATS AT THE HANFORD SITE IN SHRUB-STEPPE HABITATS IN WASHINGTON By JONATHAN GUY LUCAS A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN ENVIRONMENTAL SCIENCE WASHINGTON STATE UNIVERSITY School of Earth and Environmental Sciences May 2011

2 To the Faculty of Washington State University: The members of the Committee appointed to examine the thesis of JONATHAN GUY LUCAS find it satisfactory and recommend that it be accepted. Rodney Sayler, Ph.D., Chair Lee Rogers, Ph.D. Kenneth Gano, MSc. ii

3 ACKNOWLEDGMENT I gratefully acknowledge my bat project coworkers Ken Gano and Cole Lindsey for their support and friendship on this project, and Pat Ormsbee and the Bat Grid crew for their awesome training and support. I also thank my committee members Dr. Rod Sayler, Dr. Lee Rogers and Ken Gano for taking me through this process of learning. I especially thank my wife for her support and patience through my schooling. iii

4 USE OF UNDERGROUND FACILITIES BY BATS AT THE HANFORD SITE IN SHRUB-STEPPE HABITATS IN WASHINGTON Abstract by Jonathan Guy Lucas Masters in Environmental Science Washington State University May 2011 Chair: Rodney D. Sayler Wildlife habitat conservation on military and other large publically owned landscapes is widely recognized as critical in the United States given continuing human population growth, increasing intensity of land use, and the large number of threatened and endangered species occupying these lands. The Department of Energy s, Hanford Site, in south central Washington, was established in 1943 for atomic bomb material production during World War II. The Hanford Site encompasses 1517 km 2 (151,773 ha) of shrub-steppe landscape and now represents one of the largest blocks of such habitat in Washington. Plutonium production ended at the Hanford Site in the late 1980 s and contaminant remediation began in As part of this long-term cleanup and shutdown process, we studied two sites with bat colonies (183-F clearwell and the190-d/dr process water tunnels) to determine the extent of bat use of constructed facilities (e.g., buildings, underground tanks and tunnels), scheduled for removal or closure. We conducted mist-netting, acoustic monitoring, infrared (IR) videotaping, and visual surveys from August 2007 to August 2010 to determine the potential importance of constructed facilities to iv

5 regional bat populations. Approximately 3600 bats were discovered at 183-F, while about 340 bats were found at the 190-D/DR water tunnel, with each site containing maternity colonies. Genetic analysis of wing punch tissue from both colonies indicated the presence of Yuma myotis (Myotis yumanensis) and revealed ten overlapping matrilines between the two colonies, but no significant difference in their frequencies. Acoustic monitoring at 183-F indicated spring and summer maternity activity started to increase about mid-march. Surprisingly, some acoustic calls were recorded through fall and winter, with calls still being recorded down to minimum air temperatures of C (7.1 0 F), indicating that not all individuals left the Hanford Site during winter. The 183-F clearwell is the largest known maternity colony of Yuma myotis (Myotis yumanensis) in Washington State and demonstrates the importance of assessing artificial structures potentially slated for removal or modification to assess their ecological importance for western bat species. Consequently, the 183-F structure was saved from potential future demolition and remains an important resource supporting regional bat populations. v

6 Contents ACKNOWLEDGMENT... iii Abstract... iv Introduction... 1 Study Area... 3 Methods... 7 Field Sampling... 7 Results... 9 Discussion Literature Cited vi

7 List of Tables Table 1. Summary of bat species identified in studies conducted on the Department of Energy s Hanford Site, Washington, Table 2. Age and Reproductive Status of Bats Captured at the 183-F and 190-DR, through List of Figures Figure 1. U.S. Department of Energy s Hanford Site, in south-central Washington State Figure 2. Installed bat gate at the entrance to the Yuma myotis (Myotis yumanensis) maternity colony at the 190-DR Process Water Tunnel Figure 3. Frequency of maternal genetic lines (matrilines) at two study sites on the Hanford Site, Washington, identified through mtdna analysis of Yuma myotis (Myotis yumanensis) Figure 4. Bat acoustic activity collected by using an AnaBat SD-1 acoustic recorder stationed outside the 183-F East Clearwell Flume flume entrance, October 9, 2007 to February 19, Figure 5. Bat acoustic activity collected by using an AnaBat SD-1 acoustic recorder stationed outside the 183-F West Clearwell access hatch, February 20, 2008 to June 29, Figure F Clearwell ceiling temperature recorded October 3, 2007 to September 6, Left arrow on X-axis indicates approximate start of maternity colony activity and right arrow the time of young fledging vii

8 Introduction The United States federal government currently owns and manages about 264 million hectares (652,358,207 acres) of land, which is nearly 29% of the United States (Stein et al. 2008). The Department of Defense manages over 10 million ha (25 million acres, including habitat for some 220 endangered species (Burton and Williams 2001). The Department of Energy manages nearly 1 million ha (2.4 million acres) on about 50 sites. While the importance of private lands are critical to the conservation of many species (Hilty and Merenlender 2003), it is increasingly recognized that federal and state lands also provide protection for important habitats for many species for a variety of reasons, especially the protection of large, relatively undisturbed landscapes that might otherwise have been developed. In the arid western U.S., large expanses of the shrub-steppe ecosystem have been lost to farming, ranching, or catastrophic fires (Dobler et al. 1996), to the point that the conservation of this ecosystem and a large number of constituent plant and animal species is a matter of increasing conservation concern. The Department of Energy s, Hanford Site (Fig. 1), in south central Washington, was established in 1943 for atomic bomb material production during World War II as part of the Manhattan Project. Production and use of chemical and radiological materials occurred there from about 1943 to the late 1980s. The Hanford Site encompasses 1517 km 2 of shrub-steppe landscape and now represents one of the largest remaining blocks of such habitat in Washington (Dobler et al. 1996). Weapons production ended on the Hanford Site in the late1980 s and environmental remediation of the entire site began in As part of this longterm shutdown and cleanup process, we studied two facility sites harboring bat colonies (183-F clearwell and the 190-D/DR process water tunnels) to determine the extent of bat use of 1

9 constructed facilities (e.g., buildings, underground tanks, and tunnels) scheduled for removal or closure. Numerous environmental and ecological studies on fish, ungulates, rodents, and birds have been conducted on the Hanford Site since 1943 to assess the potential biological uptake of any chemical or radiological contaminants caused by weapons production. However, relatively little information is available on species richness, abundance, distribution, habitat requirements, and other basic ecological information on bats occupying either the Hanford Site or the shrub steppe ecosystem in central and eastern Washington (Christy et al 1995 and Gitzen et al 2002). Due to their secretive and nocturnal nature, bats are difficult to study or require specialized techniques and equipment to survey populations, and consequently, relatively few such studies have been undertaken on the Hanford Site (Table 1). Major constructed facilities, such as buildings, towers, and underground structures (e.g., tunnels and underground water storage basins) have been in place on the Hanford Site since about While these facilities were not intended for use by wildlife, bats routinely colonize buildings and other human-built structures for day and night roosting or even as nursery sites for rearing young (Kunz and Reynolds 2003, Lausen and Barclay 2006 (b)). Because such artificial habitat is limited on the Hanford Site, more information is needed to determine the ecological importance of these facilities and the potential effects of their closure or removal on bat populations. We studied bat communities at the Hanford Site from 2007 to 2010 to determine which species were present, understand genetic relationships of populations at several different facilities, and to describe how bats were using artificial structures that were scheduled for demolition. This information is important for conservation planning for bats, because it reveals the unintended consequences of human development on local wildlife populations, and it also 2

10 illustrates the relatively unseen potential importance of artificial structures as habitat for bats. Two locations with apparent bat activity are known to occur on the Hanford Site, the 100- D/DR reactor process water tunnels and the 100-F reactor underground filtered water storage basins (i.e., clearwell basin). These sites and other former nuclear reactor sites along the Columbia River are currently being remediated under direction of the U.S. Department of Energy (DOE). The overall objective of this study was to support the DOE's Columbia River corridor cleanup process and potentially guide how bat habitats are managed during this process. Our study on the Hanford Site specifically was designed to: 1) describe existing bat populations (i.e., species identification; estimate population size and sex/age structure), 2) assess patterns of daily and seasonal use of constructed facilities (e.g., presence of lactating females and size of maternity colonies), and 3) determine the potential biological and ecological importance of facilities to local and regional bat populations. Our working hypothesis, based on the apparent general mobility and seasonal movements of bats in temperate regions, was that there would not be substantial genetic differentiation among bat populations at different facilities on the Hanford Site. We collected wing-punch tissue samples and analyzed maternal DNA structure for one species of vesper bat, Yuma Myotis (Myotis yumanensis), as a first step toward evaluating this working hypothesis. Study Area The Hanford Site includes nine reactor facilities built on six sites along the Columbia River. In 1989, four large parcels of land at the Hanford Site were placed on the National Priorities List (NPL) under the authority of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) for environmental cleanup. One of these parcels is known as the 100 Areas where the former plutonium production reactors are located along the Columbia River. Placement on the NPL initiated the CERCLA process that would lead to the 3

11 environmental remediation of radioactive or chemically contaminated areas. Waste site cleanup under interim action Records of Decision (RODs) was initiated during the mid-1990s, and the 100 Areas are planned for completion of remediation efforts by The cleanup plan for the reactors is to demolish and remove all associated structures, including support facilities, and seal up the reactor buildings by installing new roofs to prevent animal intrusions. The intent is to place the reactors in a state of Interim Safe Storage (ISS) for final demolition at a later date. During the cleanup and demolition of various reactor facilities, workers have observed bats on numerous occasions. Dead specimens have been collected over time and preserved in the R.E. Fitzner Natural History Collection located at the Washington State University, Tri-Cities campus, Richland, Washington. Previous bat related projects have been associated with ISS projects, conducted at two reactor sites, the 105-DR reactor and 105-F reactor, to mitigate for roosting habitat that was lost because of cleanup projects. Ecological reviews conducted by Washington Closure Hanford (WCH) prior to the initiation of these projects, identified the presence of multiple bat species utilizing the reactors as maternity roosts for rearing young. Two species of Myotis bats, including Yuma myotis (Myotis yumanensis) and Western small-footed myotis (Myotis ciliolabrum) have been found at both areas, while Pallid bats (Antrozous pallidus) occur at the 105-F Reactor (Johnson and Gano 2006). The first study site is located at River Mile on the Columbia River at the 190-DR process water tunnels. This site is located 13.0 km (8.1 mi) upstream of the 100-F reactor site, and the tunnels are located approximately 0.97 km (0.6 mi) from the Columbia River shoreline. The 105-D reactor operated from 1944 to 1967 and the 105-DR reactor operated from 1950 to 1964 (DeNeal 1970). Mitigation projects at 100-D Area were initiated when a bat colony (Myotis sp.) was discovered in one of the process water tunnels connected to the 105-DR Reactor. The 4

12 ISS Project Plan included isolating the tunnels from the reactor, which would eliminate bat access to the tunnels and cause the loss of the maternity roost. Approval and concurrence from the U.S. Department of Energy, Richland Operation Office on July 28, 1998, provided direction to maintain bat access and mitigate for roosting habitat that would be lost as a result of the ISS project. Alternate accesses were provided on both tunnel systems that entered the 105-DR reactor valve pit by installing bat gates on access hatches (Figure 2). One tunnel originated at the 190-D Water Pump House, as a redundant water supply, and two tunnels originated from the 190-DR Water Pump House and come together just west of the valve pit. The original purpose of these tunnels was to provide the primary cooling water supply for the 105-DR Reactor. The non-contaminated process water tunnels were built with a zig-zag design to allow for expansion of the piping. Each straight leg of the tunnels contains a surface hatch to provide access in case a pipe section had to be replaced. The bat gates were placed over hatches on both tunnel systems. The gate on the 190-D tunnel was installed in the fall of 1998, and the gate on the 190-DR tunnel system, fall of Monitoring of bat roosting began in July The 190-D tunnel has not been entered since the reactor valve pit was backfilled, because there is no walk-in access available. The 190-DR tunnels have had walk-in access that has allowed inspections of the tunnels. These inspections were conducted from 2002 to 2005 and the number of bats roosting in the hatches ranged from 97 to 170 bats (Johnson and Gano, 2006). The second study site is located at the former 100-F nuclear reactor facility (River Mile 369), about 41.0 km (25.5 mi) north of Richland, Washington, and is located 430 m (1,410 ft) from the shoreline of the Columbia River. The 105-F reactor's former 183-F clearwell facility, was reported in 2006 to contain is an estimated 1000 to 2000 bats of unknown species (Gano and Lucas 2006). Bats were first noticed near this facility in the summer of 2003 (Gano 2006). 5

13 The 105-F reactor was in operation from 1945 to 1965 (DeNeal 1970). This site consists of two underground 14,157 kiloliter (3,740,000 gal) concrete basins called clearwells that held clean, filtered river water from the water treatment plant. The facility was used to store filtered riverwater prior to being used as cooling water in the 105-F Reactor. Each clearwell is about 41 m (134 ft.) wide by 114 m (375 ft.) long by 5 m (16 ft.) deep. The east clearwell has been demolished and backfilled with soil. The roof of the west clearwell is a 15.2 cm (6 in) thick concrete slab supported by interior columns. Bats have been using the west clearwell and are entering and exiting through an open maintenance hatch that is cm (42 in) square that was opened at an unknown time many years ago. On the north side of both clearwells there is a 229-m (~750-foot) long underground concrete flume that is 1.3 m wide by 2 m high (4 ft by 6.6 ft) that functioned as a drain for the water treatment plant. Bats appear to be utilizing this flume to an unknown extent (Gano and Lucas 2006). It was unknown how bats were utilizing the western clearwell or the flume. No studies had been conducted to identify the species present, their relative abundance, or how the bats were utilizing these structures in the spring and summer, or potentially the winter. As part of the River Corridor Closure contract carried out for the Department of Energy, the 183-F clearwell facility was scheduled for demolition. Before demolition could take place, the impacts that demolition would have on the bats roosting in the structures needed to be understood. The two study sites are surrounded by shrub-steppe vegetation, dominated by Big sagebrush (Artemisia tridentata) with bunchgrass understory (DOE/RL 96-32). At first farming and then construction of the Hanford Site in 1943 and development of the reactor areas has disturbed much of this native plant community near the Columbia River. This disturbance has allowed the extensive introduction of non-native species such as cheatgrass (Bromus tectorum), 6

14 Russian thistle (Salsola kali), and tumble mustard (Sisymbrium altissimum). The majority of the Hanford Site, however, remains relatively undisturbed and functions as a sanctuary to many native plant and wildlife species. Methods Field Sampling Bats were captured during eight nights at both study sites from August 27, 2007 to May 27, 2008 utilizing a bat mist net (Avinet) set near the identified roosting sites at each of the two study sites during the bats active season, which is from mid-march through September (personal observations). Nets were set at locations to optimize capture near emergence openings, but not so close as to interfere with emergence. Based upon previous observations of bat emergence times and duration, nets were open from about 15 to 20 minutes after sunset to at least one hour after bat emergence occurred, which is typically 30 minutes after sunset, so that a representative sample of the population at the study site was collected. Mist nets were open for an average of 2 hours per netting session. Data were collected from captured bats that included age (adult or sub-adult), forearm length, sex, reproductive status, species, weight, and a 3-mm wing membrane tissue punch. These data were collected using protocols established by the Bat Grid Inventory and Monitoring Project (2010) and Vonhof (2002). Determination of the species of the bats captured at both sites was conducted by collecting a 3-mm wing membrane punch from captured bats between their third and fourth finger on the left wing. Twenty two wing membrane tissue samples from the 190-DR study and sixty three wing membrane tissue samples from the 183-F study site were sent to Portland State University (PSU) for genetic analysis of mitochondrial DNA (mtdna) to identify species using methods described in Zinck et al Genetic analysis of mtdna, specifically Myotis 7

15 yumanensis, to identify matrilines (i.e. maternal lines) for both study sites was determined per methods described in Vonhof et al All genetic analysis was conducted by Dr. Jan Zinck at PSU. We used a two-tail Z-test for comparing the frequency of the matrilines identified from genetic analysis of tissue samples collected at each of the sites. Population size and emergence time for bats was estimated by videotaping the emergence of each study site population using a Sony Night Shots video camera (model # DCR-TRV103) with auxiliary IR (infrared) lights for two hours, and by visual counts of roosting bats. Total emergence was estimated by counting the number of bats observed (on the recording) emerging from the roost sites for each minute over the two hour video tape recording. We assessed whether the study sites were also maternity colonies by recording the reproductive condition of adult female bats captured during mist-netting sessions. Because of the challenges of conducting an emergence count from a bat gate, due to multiple emergence paths and bats returning to the roost, a bat out minus bats in count was conducted, and the given count is possibly a conservative estimate of the actual numbers of emerging bats. We determined seasonal activity patterns for bats by examining temporal (spring, summer, autumn and winter) usage patterns of the 183-F clearwell through collection of acoustic data at roost entrances utilizing an AnaBat SD-1 acoustic detector and visual roost surveys. All acoustic data was collected by setting up an AnaBat SD-1 detector in a weatherprotected enclosure on a post with the microphone pointing down toward a board set at approximately 45 degrees. The detector was set to turn on at approximately 1600 hrs and turn off at approximately 0700 hrs. AnaBat acoustic data was analyzed using an Allbats detection filter (Corben, C. 2010). Acoustic signals, which are composed of a series of frequency pulses that were of a quality to pass the filter, were counted as bat detection. 8

16 Results In August 2009, an emergence count at the 183-F clearwell and clearwell flume entrance was conducted; and the total emergence was estimated to be 2,640 individuals from the clearwell hatch, and approximately 120 bats from the flume entrance (WCH-362). Emergence counts were again conducted in 2010 at the 183-F clearwell, with a count of 3,539 in June and 3,637 in August. Numbers seem to indicate a growing colony, but more yearly counts would be needed to better assess this trend. The 190-D process water tunnel was isolated from the 190-DR process water tunnel when the ISS project at 105-DR reactor demolished the valve pit where the tunnels entered the reactor. Each tunnel now has its own bat gate and Yuma myotis use both process tunnel gates, although separated, both tunnels likely function as one maternity colony because of their proximity. Counts of bats in the 190-DR tunnel have been conducted in previous years during walk-throughs of the tunnel by visually counting bats seen roosting in the tunnel. The numbers counted were 107 in 2002, 99 in 2003, 98 in 2004, 97 in 2005, a second survey in 2005 indicated 170, 108 in 2007, 67 in 2008, and 77 in 2009 (WCH-288 and WCH-362). Approximately 340 Yuma myotis were counted emerging from the 190-D water process tunnel gate in July, Because of the proximity of the two tunnels, the bats could easily move from one tunnel to the other throughout the season which could account for the variability in the population counts done inside the 190-DR tunnels, including the timing of the counts also. 9

17 Sex, age and reproductive status information collected during mist-netting at both study sites indicated a high percentage of females compared to males, and high percentages of postlactating and parous females. This data shows that both sites contain maternity colonies (Table 2). Genetic analysis performed on tissue samples from bats using the 183-F (n=63) and 190-DR (n=22) study sites resulted in all samples being identified as Yuma myotis. Maternal mtdna analysis yielded ten matrilines (labeled A through J) from both study sites. The relative frequencies of the matrilines sampled at the two roosting sites were not significantly different (Figure 3). To describe seasonal activity patterns of bats using the tunnels and clearwell, we collected automated acoustic recordings to detect bats outside the 183-F clearwell emergence hatch and the clearwell s east flume entrance from October 9, 2007 through June 29, 2008 (Figures 4 and 5). A large decrease in bat acoustic activity occurred around October 17, 2007, and activity levels appeared to drop to low winter levels by about November 9, By late March of 2008, bat activity increased rapidly from low winter activity to higher spring and summer activity levels (Fig. 5). 10

18 One interesting record of bat activity occurred January 23 to 24, 2008 when five acoustic bat passes were detected when an average minimum nighttime temperature of o C (7.1 o F) was recorded at a weather station about 2.8 km south of the 183-F study site. This observation correlated with a study of winter bat activity in southeastern Alberta, Canada, where bats were monitored at two rocky areas along the Red Deer River. Bats were found to be active even when ambient temperatures were below 0 o C during the day and night; the coldest temperature observed with bat activity was -8 o C (Lausen and Barclay 2006 (a)). What is behind winter activity is not well understood, and much more study is needed in this particular area of bat ecology (Falxa 2007, and Lausen and Barclay 2006 (a)). We collected ad hoc observations of roosting bats observed during entries into the 183-F flume to deploy and retrieve a temperature and humidity data logger. We observed approximately 200 to 300 Yuma myotis roosting within the first 90 meters of the flume entrance on October 3, 2007 during data logger deployment. These bats were observed roosting in clusters on the cement wall near the ceiling of the flume. On September 30, 2008 we entered the flume again to retrieve the data logger, and observed approximately 200 Yuma bats roosting in clusters near the ceiling and in a ceiling pipe annulus. The roosting clusters were composed of both male and female bats based upon hand capture identification of a small sample of bats. An entry was made inside the 183-F clearwell during June 2008 to videotape the maternity colony when the females would be present in high numbers with associated maternal activity. Filming with IR lighting showed that the females were in large clusters on roof support columns near the ceiling. Clearwell ceiling temperatures later obtained from a data logger were approximately 10 o C (50 o F) in early April at the beginning of maternity colony activity and about 32 o C (90 o F) by the time the pups fledged at the end of June (Fig. 6). 11

19 In addition to acoustic recordings, we also conducted occasional mist-netting sessions once or twice during spring and summer. We captured a male Western small-footed myotis (Myotis ciliolabrum) at the 183-F study site on August 18, 2009, along with the expected Yuma myotis. The male was light-tagged per Bat Grid Inventory and Monitoring Project (2010) protocols, so an acoustic call could be recorded. The bat flew around for a few minutes, and then it was observed flying into the clearwell through the roof hatch of the 183-F clearwell, where the Yuma myotis colony is located. Other Western small-footed myotis occasionally have been captured and acoustically recorded at other nearby reactor sites, which may indicate they are using the same common roosting areas as the Yuma myotis. Discussion About 10 species of bats have been identified on the Hanford Site since 1991; however, accurate identification of western bat species can be difficult because of morphologically cryptic species (Weller et al. 2007). Increasingly, molecular techniques are being employed to discriminate among cryptic species and help define morphological characteristics useful in identifying bats (Zinck et al. 2004; Weller et al. 2007). Nonetheless, even if the accuracy of historical identifications is unknown, this apparent diversity of bats on the Hanford Site is either comparable or relatively high for that known for other areas in eastern Washington and other shrub-steppe habitats in the inland Pacific Northwest (Gitzen et al 2002). Buildings, underground tunnels, clearwells, flumes, and other structural facilities on the Hanford Site obviously were never designed with the intention that they would be used by wildlife. However, our surveys demonstrate that bats have readily colonized and now occupy some of these sites in high densities. Furthermore, our study demonstrates that both bat roosting areas are maternity colonies for Yuma myotis (Myotis yumanensis). High percentages of the females in these roosts are parous or post-lactating, which is indicative of maternity colonies and a large 12

20 proportion of adult females we observed were raising pups during the breeding season. Bats are homeothermic and maintain a body temperature of about 35 o to 39 o C (95 o to 102 o F), and consequently, they attempt to roost in a thermoneutral temperature zone to reduce energy expenditures (Neuweiler 2000). Maintaining an optimum body temperature is especially important for females in maternity colonies to facilitate embryo development, lactation, and growth and fledging of pups. The ceiling temperatures we measured in the clearwells correspond well with a study that compared maternity colonies in building structures versus rock maternity colonies utilized by Big Brown bats (Eptesicus fuscus). Maximum-recorded temperatures in a school attic were about 30.8 o C ± 0.6 o C (87.4 o F) while maximum temperatures in rock colonies were about 28.4 o C ± 0.6 o C (83.1 o F). Young fledged around July 28, one to two weeks earlier in the school structure than those in the rock roosts (Lausen and Barclay 2006 (b)). Higher temperatures in some artificial structures used for bat maternity colonies appear to favor pup development (Lausen and Barclay 2006 (b), Zahn 1999), illustrating the potential importance of building structure as habitat for bats. The initial analysis of maternal mtdna genetic lines suggests that bats at the two sites located approximately 7.5 km (4.7 miles) apart (line of sight) may constitute parts of a larger population. Additional tissue sampling of bats over a larger area would be required to better determine what genetic patterns may occur over the regional shrub-steppe landscape. However, the current genetic analysis suggests that bats within different roosting sites within the Hanford Site may constitute a single genetic population. Our count of approximately 3,600 Yuma bats at the 183-F study site in August 2010 makes this the largest known colony of this species in Washington State. We also found that at least 10 species of bats have been identified on the Hanford Site since Relatively little 13

21 comparative information is available about the distribution, abundance, and species diversity of bats in unaltered shrub-steppe environments in the western United States. Therefore, while it might be argued that these local populations did not exist prior to human settlement and development of the Hanford Site, there are insufficient data to make this determination. Consequently, complete closure of facilities once used to support operation of the nuclear reactors at the Hanford Site poses both biological and ethical issues in bat conservation. The biological issue is primarily whether complete loss of these roosting and maternity habitats through the closure or removal of artificial structures at the Hanford Site would negatively or unduly impact regional bat populations. Without having adequate comparative data on other bat populations in eastern Washington it is not possible to draw definitive conclusions about the importance of bat populations on the Hanford Site to regional populations. However, the large number of roosting bats suggests that the Hanford Site may be providing an important ecological resource for bats in this area. The ethical issue surrounding elimination of structural facilities used by bats on the Hanford Site is whether what appears to be a thriving and reproducing bat population should be eliminated during removal and closure of decommissioned DOE facilities. Whether or not the habitat is natural does not answer the question of how much the regional population may depend on these habitats, which appear to provide good maternity sites for raising pups. Consequently, additional information is clearly needed to determine the status and population ecology of bats in shrub-steppe and other areas in the western United States. Given that the cost of protecting these bat roosting areas on the Hanford Site are relatively low, we recommended that these particular facilities be protected and managed as important regional bat habitat. As a result of this study, this non-contaminated structure was 14

22 saved from demolition, and is now the largest known maternity colony of Yuma myotis in Washington State, indicating its potential importance to regional bat populations. Further studies are needed on this colony to better understand its place in supporting bat populations in this region. 15

23 Literature Cited Bat Grid Inventory and Monitoring Project ( Becker, J. M A Preliminary Survey of Selected Structures on the Hanford Site for the Townsend's Big-Eared Bat. PNL Pacific Northwest Laboratory, Richland, Washington Burton, L., and T. Williams This Bird Has Flown: The Uncertain Fate of Wildlife on Closed Military Bases. Natural Resources Journal Vol. 41: Christy, R., S. Paulus, and J. Duncan Ecology of Bats on the Yakima Training Center. Doc. Number United States Army, Yakima, Washington. Corben, C (personal communication). DeNeal, D. L Historical Events- Single Pass Reactors and Fuels Fabrication. DUN Douglas United Nuclear, Inc., Richland, Washington. Dobler, F.C., J. Eby, and C. Perry Status of Washington s Shrub Steppe Ecosystem. Shrub-Steppe Research Project: Phase one completion report. Washington Dept. of Fish and Wildlife. 39 pp. DOE/RL Revision 0, August Hanford Site Biological Resources Management Plan. United States Department of Energy, Richland, Washington. 16

24 Falxa, G Winter Foraging of Silver-Haired and California Myotis Bats in Western Washington. Northwestern Naturalist 88: Fitzner, R.E., and R.H. Gray The Status, Distribution and Ecology of Wildlife on the U.S. DOE Hanford Site: A Historical Overview of Research Activities. Environmental Monitoring and Assessment 18: Gano, K.A Personal communication. Washington Closure Hanford Company, Richland, WA Gano, K.A., and J.G. Lucas Visual Surveys on and Washington Closure Hanford Company, Richland, WA Gitzen, R.A., J. L. Erickson, and S.D. West Bat Activity and Species Occurrence on the Hanford Site in Eastern Washington. Northwestern Naturalist 83: Hilty, J., and A.M. Merenlender Studying Biodiversity on Private Lands. Conservation Biology Vol. 17 No. 1: Johnson, A.L., and K.A. Gano River Corridor Closure Contractor Revegetation and Mitigation Monitoring Report, WCH-133, Rev. 0. Washington Closure Hanford, Richland, Washington. Kunz, T.H., and D.Scott Reynolds Monitoring Trends in Bat Populations of the United States and Territories: Problems and Prospects- Bat Colonies in Buildings. Information and Technology Report USGS/BRD/ITR Pages Lausen, C.L., and R.M.R. Barclay (a). Winter Bat Activity in the Canadian Prairies. Canadian Journal of Zoology, 84:

25 Lausen, C.L., and R.M.R. Barclay (b). Benefits of Living in a Building: Big Brown Bats (Eptesicus Fuscus) in Rocks Versus Buildings. Journal of Mammalogy, 87(2): Neuweiler, G The Biology of Bats. New York, Oxford, Oxford University Press. Soll, J., J.A.Hall and R. Pabst Biodiversity Inventory and Analysis of the Hanford Site, Final Report: The Nature Conservancy of Washington. Stein, B.A., C. Scott, and N. Benton Federal Lands and Endangered Species: The Role of Military and Other Federal Lands in Sustaining Biodiversity. BioScience Vol. 58 No. 4: Vonhof, M., Handbook of Inventory Methods and Standard Protocols for Surveying Bats in Alberta. Prepared by Echo Biological Consulting Inc. for Alberta Fish and Wildlife Division, Edmonton, Alberta. Vonhof, M.J., C. Strobeck, and M.B. Fenton Genetic Variation and Population Structure in big brown bats (Eptesicus fuscus): is female dispersal important? Journal of Mammalogy, 89(6): WCH-288, Revision 0, River Corridor Closure Contractor Revegetation and Monitoring Report. Washington Closure Hanford, Richland, Washington. WCH-362, Revision 0, River Corridor Closure Contractor Revegetation and Monitoring Report. Washington Closure Hanford, Richland, Washington. Weller, T.J., S.A. Scott, T.J. Rodhouse, P.C. Ormsbee, and J.M. Zinck Field Identification of the Cryptic Vespertilionid Bats, Myotis lucifugus and M. yumanensis. Acta Chiropterologica, 9(1):

26 Zahn, A., Reproductive success, colony size and roost temperature in attic-dwelling bat Myotis myotis. Journal of Zoology (London), 247: Zinck, J. M., D.A. Duffield and P.C. Ormsbee Primers for Identification and Polymorphism Assessment of Vespertilionid Bats in the Pacific Northwest. Molecular Ecology Notes 4:

27 Table 1. Summary of bat species identified in studies conducted on the Department of Energy s Hanford Site, Washington, Species Identified- X Fitzner and Gray (1991) Becker (1993) Christy et al (1995) Soll et al (1999) Gitzen et al (2002) This Study Study Description Historical overview of wildlife research from the Hanford Site's beginning in 1943 to Six-week survey of selected building structures on the Hanford Site to survey for Townsend's bigeared bat (Corynorhinus townsendii). Visual surveys and acoustic monitoring was utilized. Study conducted at the U.S. Army Yakima Training Center (506 sq. miles) during the summer of 1994 to assess bat species diversity and abundance across various habitat types. Mist-netting, acoustic monitoring and roost surveys were utilized to conduct this assessment. Study conducted by The Nature Conservancy for the U.S. Department of Energy on the Hanford Site from 1994 to 1998 (no field work occurred during 1996) to inventory plants, animals and ecologically significant areas of the Hanford Site utilizing acoustic recording, mistnetting, harp traps and visual/auditory surveys for bat inventory. Conducted a survey for bats on the Hanford Site during 1997 and 1998 using acoustic monitors, mistnets, harp traps and audio-visual observations in an effort document species occurrence and compare activity level among major habitat types of the Hanford Site. Conducted survey during 2007 to 2008 to determine species present, genetic relationships, temporal and spatial activity patterns, and determining reproductive status of two bat colonies at 183-F and 109-DR facilities. Acoustic monitoring, mistnets, and video surveys were used. Pallid bat (Antrozous pallidus) Big brown bat (Eptesicus fuscus) Hoary bat (Lasiurus cinereus) Silver-haired bat (Lasionycteris noctivagans) X X X X X X X X X X X X X X X X X California myotis (Myotis californicus) X X Western small-footed myotis (Myotis ciliolabrum) X X X 20

28 Species Identified- X Fitzner and Gray (1991) Becker (1993) Christy et al (1995) Soll et al (1999) Gitzen et al (2002) This Study Little brown bat (Myotis lucifugus) Long-legged bat (Myotis volans) Yuma myotis (Myotis yumanensis) X X X X X X X X X X Unidentified Myotis sp. X X Western pipistrel (Pipistrellus hesperus) X X X 21

29 Table 2. Age and Reproductive Status of Bats Captured at the 183-F and 190-DR, through Study Site Adult Females % Post Lactating % Parous % Adult Males % 183-F (n = 72) 190-DR (n = 22) 22

30 Figure 1. U.S. Department of Energy s Hanford Site, in south-central Washington State. 23

31 Figure 2. Installed bat gate at the entrance to the Yuma myotis (Myotis yumanensis) maternity colony at the 190-DR Process Water Tunnel. 24

32 Figure 3. Frequency of maternal genetic lines (matrilines) at two study sites on the Hanford Site, Washington, identified through mtdna analysis of Yuma myotis (Myotis yumanensis). 25

33 Figure 4. Bat acoustic activity collected by using an AnaBat SD-1 acoustic recorder stationed outside the 183-F East Clearwell Flume flume entrance, October 9, 2007 to February 19,

34 Figure 5. Bat acoustic activity collected by using an AnaBat SD-1 acoustic recorder stationed outside the 183-F West Clearwell access hatch, February 20, 2008 to June 29,

35 Figure F Clearwell ceiling temperature recorded October 3, 2007 to September 6, Left arrow on X-axis indicates approximate start of maternity colony activity and right arrow the time of young fledging. 28