ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
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ECHOLOCATOR Volume 10 Issue 1 Feb. 2021 EC HO LO C ATO R In A World Turned Upside Down Thank You For Helping Us Through 2020
2 Wisconsin Bat Program • 2021 Table Of Contents 15 5 8 Wisconsin Bat Program The Wisconsin Department of Natural Resources (DNR) provides equal opportunity in its employment, programs, services and 3 Editor’s Note functions under an Affirmative Action Plan. If you have any questions, please write to Equal Opportunity Office, Department of Interior, 4 Q & A With Bat Team Leader Washington, D.C. 20240. This publication is available in alternative format (large print, 5 Winter Surveys Show Average 89% Drop Braille, audio tape, etc.) upon request. Please call 608-261-6449 for more information. Echolocator is an annual publication of the 7 Cave & Mine Catalogue Update Wisconsin Bat Program, part of the DNR’s Natural Heritage Conservation Program. DNR 8 Acoustic Bat Monitoring Update conservation biologists statewide monitor, research and inventory Wisconsin’s eight bat species in collaboration with other state and 14 Wisconsin-Based Research federal agencies, universities, conservation groups, other non-governmental 15 Diet Study Reveals Bats’ Importance To Ecosystem groups and hundreds of volunteers. Echolocator presents bat conservation work 18 Bats With White-Nose Syndrome Prefer Suboptimal and research relevant to Wisconsin and Habitats Despite The Consequences welcomes ideas for future articles and featured groups. Please contact Jennifer.Redell@wisconsin.gov to share your suggestions. Editor, Jennifer Redell Graphic Design, Rebecca Rudolph State of Wisconsin Department of Natural Resources In a world seemingly flipped upside down, reaching out Box 7921 to friends helped us get by in 2020. These hibernating Madison, WI 53707 little brown bats paired up to make it through the winter. Photo, flipped for effect: Heather Kaarakka WISCONSIN BAT PROGRAM WEBSITE: WIATRI.NET/INVENTORY/BATS/
3 Wisconsin Bat Program • 2021 Reflections From The Editor Hundreds Of Volunteers Fly In To Help Bats “What remained By Jennifer Redell Some of our typical winter 2021 work DNR Conservation Biologist, Bat remains on hold due to COVID-19. Our Program Cave and Mine Specialist routine winter hibernation surveys constant, however, will be much more limited in the Similar to most people, COVID-19 was the dedication of coming months while we wait our impacted our work in direct and turn for the COVID-19 vaccine and indirect ways. Some things looked the volunteers who the possibility of again searching the same, many tasks were modified play a vital role in caves and mines with colleagues. Our or dropped, and we forged ahead using technologies allowing us to helping us understand longstanding safety practice has been to search underground hibernacula track bats remotely. What remained the changes we’re only with a group of people. constant, however, was the dedication seeing in Wisconsin of the volunteers who play a vital We’re capitalizing on technologies role in helping us understand the bat populations due that allow us to track bats and learn changes we’re seeing in Wisconsin to WNS. more about them remotely. Relatively bat populations due to white-nose syndrome (WNS). of Wisconsin-Madison has been ” new antenna systems installed at several hibernacula will allow us to read the activity of bats carrying Despite the many challenges of the instrumental in our understanding of Passive Integrated Transponders past year, Wisconsin Bat Program bat diets in Wisconsin, and how little (PIT) tags. As we move into summer, volunteers monitored more roosts brown bats are especially important thermal cameras and PIT tag readers and completed a greater proportion for filling an important role as an will help us better understand what’s of acoustic surveys during a ecosystem predator and for their going on inside roosts. significantly shortened monitoring voracious consumption of agricultural season. This work from dedicated pests and mosquitos. She summarizes As bats emerge from caves on to the volunteers is critical in helping her research in this issue and we wish landscape and migrate home from us observe how populations are her well as she begins work at the other states where they over-wintered responding after WNS caused severe University of Wyoming to improve later this spring, we hope our outdoor declines at the majority of Wisconsin how chronic wasting disease in deer summer work can be conducted in a hibernation sites beginning six years can be studied. mostly normal way. ago. Researchers Skylar Hopkins, Kate Whatever may come, we remain Our streamlined newsletter Langwig and Joseph Hoyt of Virginia especially grateful for the dedication summarizes these surveys and Tech publish results of their long- of, and the inspiration provided by, other core activities and highlights term study to see if bats alter their hundreds of volunteers working two key partnerships. Amy Wray’s roosting preferences in hibernacula in individually or with members of their doctoral research at the University response to the arrival of WNS. household to help Wisconsin bats.
4 Wisconsin Bat Program • 2021 Bat Q & A With J. Paul White Right now, Wisconsin’s four cave bat species are in their winter hibernation sites. Since white-nose syndrome was first detected in a Grant County mine in 2014, the disease has spread to hibernation sites statewide and resulted in dramatic decreases in overall bat populations, with losses at sites ranging from 70-100 percent. Little brown bats, eastern pipistrelles, also known as tricolored bats, and northern long-eared bats have been hit hardest while big brown bats have fared better. We catch up with J. Paul White, DNR Mammal Ecologist and Bat Program Northern-long eared bats have fared the worst from Lead, to understand the latest news white-nose syndrome. Photo: Heather Kaarakka for Wisconsin bats. Q: Where are Wisconsin bat sense to manage forest 100 miles populations today? Q: What’s next? from a hibernaculum when species J. Paul White: The picture is still J. Paul White: Our mission is to work typically migrate shorter distances. developing and we see both signs with others to identify, protect, Identifying core use areas by bats is of encouragement and cause for monitor and manage populations also critical for understanding best concern. of native bat species; enhance management practices for forests, as and restore their habitats; address bats have been shown to return to the We incorporate survey data collected human-bat coexistence, and promote same summer habitat in consecutive by volunteers, agencies and partners knowledge, appreciation and years. In addition, little to nothing is from winter hibernation sites, summer stewardship of bats in Wisconsin for known about the connection between maternity roosts, and state-wide present and future generations. winter hibernacula and active surveys using acoustic detectors to summer habitat for most bat species record bat calls along set routes. Guided by the national plan and in North America. Together these data describe a still the DNR’s strategy, Wisconsin’s vulnerable cave bat population, conservation and recovery efforts will Q: What can I do to help bats? prone to choosing “ecological traps” be prioritized to protect our sensitive J. Paul White: Bats continue to where seemingly suitable hibernating bat population during critical points need our help as white-nose conditions are just a deadly disguise in their life -- hibernating or raising syndrome, among other threats, (read more about research into pups -- while controlling the disease exist in Wisconsin and throughout these ecological traps on page 18.) (vaccine development) to the point the midwest. From respecting their Yet, in some areas, we see resilience where bat populations may recover. privacy in the winter, to engaging in a through summer and winter colonies citizen-based bat monitoring project, alike, as numbers appear to have Q: Broadly, what are the research to installing bat houses to support stabilized after hitting bottom. We’re questions we need answers for to these voracious insect-eaters, each also seeing welcome signs of juvenile better advance recovery? little action can have a positive recruitment, which means some J. Paul White: Understanding distances impact on learning more about their individual bats choose wisely in their traveled and how bats use the populations and/or supporting their hibernation strategies and/or are landscape surrounding permanent survival as an important part of genetically better suited to cope with hibernation sites during movement Wisconsin ecosystems. Find more the deadly fungal pathogen causing between winter and summer habitat information about ways to help on white-nose syndrome. can aid management decisions for this Bat Frequently Asked Questions species. For example, it makes little web page.
5 Wisconsin Bat Program • 2021 Winter Surveys Show Average 89% Drop In Bat Populations At 55 Sites DNR staff and Virginia Tech researchers count hibernating bats in Wisconsin in 2015. Photo: Joseph Hoyt By Jennifer Redell 55 sites in early 2020. with smaller populations reduced by DNR Conservation Biologist, Bat WNS to zero bats. Declines averaged Program Cave and Mine Specialist Hibernating bat populations 89% from their pre-WNS average previously exposed to WNS, populations at specific sites. Wisconsin Bat Program staff collected particularly in years two and three data on bat populations, species and of WNS infection, observed steep Wisconsin’s only site in its seventh distribution from bat hibernacula declines. We continued to see bat year since infection still had four infected with white-nose syndrome at populations in some hibernation sites bats hibernating in it, including one Bat population at hibernation site where WNS was first detected in Wisconsin 1200 Little brown bat Big brown bat 1000 Eastern pipistrelle Northern long-eared bat 800 TOTAL (all individuals) Individuals 600 2009- tree down over entrance 2014- WNS detected in March 400 2015- WNS second year 200 2016- WNS third year 0 1994 1996 1998 2000 2001 2003 2005 2007 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
6 Wisconsin Bat Program • 2021 northern long-eared bat. That handful These datasets have been entered of bats found in 2020 represents a into the Cave & Mine Catalogue Sobering Numbers 99.5% reduction from the site’s pre- and added to the Natural Heritage WNS average. Since the disease was Inventory, where the location and first detected in 2014, at least 64 sites other information will help the state • 35 U.S. states and 7 Canadian in 25 Wisconsin counties have been and private citizens protect and provinces confirmed with confirmed as WNS-positive or WNS- manage them. Key findings from the WNS suspect. site visits are highlighted below. • 4 more states confirmed with the fungus P. destructans (Pd), causing the disease • 12 bat species confirmed with WNS, 6 more with Pd • 5.7 to 6.7 million bats estimated dead of WNS as of 2011 • Wisconsin: 64 sites in 25 counties confirmed as WNS positive or WNS suspect. • Bat population changes have ranged from minor increases at a very few sites to 100% declines where no bats remain in a given cave or mine. Notable Observations In 2019-2020 pre-WNS average. Hibernation Season • The site where WNS was first detected in Wisconsin, now in • White-nose syndrome has now its seventh year of infection, affected cave bat populations has experienced a 99.5% in Wisconsin for seven population decline when hibernation seasons and the compared to baseline data, as WNS fungus is considered see in the graph on page 5. present in hibernation sites • The DNR has focused statewide. on understanding bat • Two of Wisconsin’s largest survivorship, immigration/ surveyed sites are down 87% emigration and fidelity to and 71% from their pre-WNS hibernation sites. To this end, Photo: Jennifer Redell average populations. Both DNR and our Virginia Tech Condensation forms on an sites originally held tens of partners banded over 1,800 eastern pipistrelle bat. thousands of little brown bats bats between fall 2019 and and other species. Both sites spring 2020. are now in their fifth year of • We continue to locate a few infection. “long-term survivor” bats in • Hibernacula now in year six the sites where they were first of disease progression have banded before discovery of experienced an overall decline WNS in Wisconsin in 2014. of over 89% compared to the
7 Wisconsin Bat Program • 2021 Cave & Mine Catalogue Update Wisconsin’s Bat year we continued to provide support to the project, the goal of which is Data Aids National to determine if immunization of bats against WNS improves their survival Species Status and/or reduces the occurrence of the disease. In 2020 two potential Assessments vaccine candidates were tested for effectiveness in little brown bats By Jennifer Redell in the field. Additionally, timing DNR Conservation Biologist, Bat of vaccination was tested, both at Program Cave and Mine Specialist summer maternity colonies and during fall swarm/early hibernation Little brown bats receive an oral WNS Results from winter 2019-2020 at hibernacula. vaccine from USGS National Wildlife hibernacula surveys in Wisconsin will Health Center staff. Photo: Jennifer help determine possible protections Passive Integrated Transponder Redell for three bat species nationally. (PIT) systems were installed at the In spring 2020, the DNR submitted primary bat entrances of two study investigating movement and bat data to the North American Bat sites in Pierce County in September transmission of Pd/WNS across the Monitoring Program (NABAT) as part 2019 to monitor activity by research midwest. of a nationwide data request by bats that were marked with a PIT tag. the United States Fish and Wildlife More than 300 little brown bats were This ongoing project is providing Service to help fill in data gaps on vaccinated and distributed among a unique look at sites before WNS three sensitive bat species being treatment groups at two hibernacula arrived, during the infection, and considered for federal protection: in Pierce County. During our regular after. In total, 20 sites were visited little brown bat, eastern pipistrelle winter surveys we opportunistically one to two times in fall 2019 and bat (aka tricolored bat) and northern re-sighted and processed (scanned, spring 2020. We provided landowner long-eared bat. These species already band read, swabbed, wing check) access and field support when receive state protection in Wisconsin, some of these project bats. In necessary. Samples from hibernacula having been added to the state addition to providing onsite support environments as well as all four cave threatened species list in 2011. during research trips, local DNR bat species were collected from fall staff changed batteries on the PIT of 2019 and through spring of 2020, Hibernacula data submitted to tag systems to allow for continuous ending just before state restrictions NABAT came from 616 site visits to reading of treatment animals to were enacted due to the pandemic. 133 hibernacula in 29 counties. Sites assess seasonal activity levels and included beer caves, railroad tunnels, survival. Take A Virtual Tour Of caves and mines surveyed between Kickapoo Caverns 2010-2020. In total, for the three cave The field trials in early 2020 Finally, if you’re keen to explore bat species across all survey years, demonstrated the vaccines were an underground space from the 1,045,029 bats were counted. safe for bats, and at least one comfort of home, join me on a virtual vaccine increased survival in males tour of Kickapoo Caverns, one of WNS Vaccine Trials Show Promise and significantly reduced levels Wisconsin’s longest cave systems Since 2014, the Wisconsin Bat of the fungus causing white-nose and an important bat hibernaculum. Program has worked with the United syndrome. More trials began this fall The online tour hosted by caverns States Geological Service National in Wisconsin to test specific vaccine owner Mississippi Valley Conservancy Wildlife Health Center, University candidates. is titled “Home to Hibernating Bats” of Wisconsin-Madison, Mississippi and is available in two parts on the Valley Conservancy and Virginia Tech Logistical Support Provided To WNS conservancy’s Youtube channel. The to develop and evaluate vaccines Transmission Study tour covers general bat ecology, to help bat populations recover, In 2020 our program continued its white-nose syndrome, how our including undertaking the first partnership with the University program and partners study bats vaccine trials in the wild for any of California- Santa Cruz/Virginia and the cave’s geology, history and disease affecting bats. In the past Tech white-nose syndrome project importance as a bat hibernaculum.
8 Wisconsin Bat Program • 2021 Acoustic Bat Monitoring Update Volunteers Take To The looked and felt very different this importantly, safely) be conducted year. Nevertheless, once we figured alone or within a family group. Or Water, Detect Mixed out how to safely monitor for bats in could it be attributed to an amazing Results For Bats mid-June, mobile acoustic bat surveys core of coordinators and volunteers began flooding in. In fact, despite who would stop at nothing to collect By J. Paul White missing the first two months of the bat data? Both likely account for such DNR Mammal Ecologist, bat monitoring season, looking at the a strong outpouring of data amidst Bat Program Lead numbers – 253 acoustic surveys in 48 very trying circumstances. A sincere (of 72) counties – one would not have thank you from the Wisconsin Bat A Year Like No Other known our volunteers were restricted Program to everyone who participated Unfortunately, due to....well, you by a pandemic. Perhaps their survey in the 2020 acoustic bat monitoring know the rest of that sentence all effort was a result of an outdoor season! too well. It’s no mystery why things activity that could easily (and more 2020 2019 150 participants 393 participants 253 surveys 376 surveys 48 counties 50 counties 109 paddling surveys 113 paddling surveys 100 driving surveys 135 driving surveys 44 walking surveys 128 walking surveys 70 surveys in Vilas County* 73 surveys in Vilas County *County with the most acoustic surveys Acoustic detector mounted on a kayak. Photo: J. Paul White Sobering Results For Two Species But catalogued. Unfortunately, not one of and streams, a finding from the bat Better News For Little Brown Bats the nearly 15,000 bat encounters was diet study Amy Wray summarizes on Volunteers, DNR staff and partners classified as a northern long-eared page 15 I think we can all agree that like the United States Forest Service bat and only six were labeled as calls more little brown bats eating flies, took part in the shortened 2020 of the eastern pipistrelle bat. The midges and mosquitoes is a good acoustic bat monitoring season. Most acoustic silence is, regrettably, also thing. The frequency of detection is surveys (94%) were one- or two- reflected in our winter hibernation likely bolstered by that fact that 84% person surveys and on average lasted surveys, in which each year fewer bats of water surveys detected little brown one hour and 20 minutes. The most of either species are observed or in bats and there were more of such surveyed areas in Wisconsin this year some cases, not found at all. surveys than either driving or walking were aquatic waterways (109 surveys) routes. – thank you Vilas County! – while Fortunately, it wasn’t all bad news. 100 surveys were driven and 44 were For every three acoustic surveys Big brown bats and hoary bats were walking routes. completed, two detected a little found on roughly 75% of all surveys brown bat, which is good news. Since completed, making them the most From these surveys, over 14,900 bat little brown bats commonly forage on frequently encountered species calls were collected, analyzed and aquatic insects found at rivers, lakes followed by little brown bats (65.2%),
9 Wisconsin Bat Program • 2021 Hoary bat. Photo: Heather Kaarakka eastern red bats (67.2%) and silver- haired bats (36.4%). See page 10 for a map of most commonly detected species. The sunset over Little Lake Butte Des Morts just before conducting a bat survey. Eastern pipistrelles and evening bats Photo: J. Paul White were found only on a total of five surveys and there were zero northern nationwide data request by U.S. Fish surveyors are active when many folks long-eared bat encounters. and Wildlife Service to help fill in data are inside for the night, there are gaps on sensitive bat species being opportunities to observe interesting With the multitude of threats bats considered for federal protection. The nighttime behavior or rare wildlife. continue to face from white-nose species -- little brown bats, eastern In some cases, we’ve passed along syndrome to wind energy-related pipistrelles and northern long-eared observations to DNR species experts mortality, the Wisconsin Bat Program bats – are already on Wisconsin’s that have helped confirm species in will continue to collect acoustic bat threatened species list. Acoustic new locations or where they haven’t data from this highly mobile and data that fit the service’s request been observed for many years, if not secretive group of mammals to assess came from acoustic bat driving decades. Here are a few observations Wisconsin’s bat population at the transects and stationary sources. surveyors turned in from 2020 routes: local, state and regional level. In total, the Wisconsin Bat Program • Driving route – Central Lake submitted 32,482 acoustic files from Michigan Coastal 1 (Shawano A Call For Data mobile surveys spanning seven years County) – “Saw a barred owl, two In spring 2020 the Wisconsin Bat (2013-2019) and 313,046 acoustic porcupine, three raccoons, many Program submitted acoustic bat data files from five stationary long-term deer. Heard whip-poor-wills in to the North American Bat Monitoring bat monitoring stations (2007-2017). Navarino State Wildlife Area and Program (NABAT) as part of a These data were not only collected eastern gray tree frogs.” by DNR staff but also federal partners • Paddling route - Little Tamarack like the U.S. Forest Service, tribal Flowage survey (Vilas County)- partners from the Bad River Band of “What a beautiful evening for a Lake Superior Chippewa Indians and bat survey! So lucky to have my volunteers. daughter and son-in-law to share the experience.” Notable Notes From This Year • Walking route - Sanders Park We encourage you to report (Racine County) - “Nice evening, your supplemental observations but bits of rain near 3/4 mark whether they relate to bat activity, - hence early quit. Had trouble the functionality of the detector walking that far - this lockdown or other interesting notes. From has eliminated staying in shape. birds, to amphibians, to mammals, Or whatever excuse is needed.” to local weather conditions or Big brown bat. other “interesting” comments, we Stay safe and best wishes for 2021. Photo: Dave Redell will happily accept all notes. Since
11 Wisconsin Bat Program • 2021 Roost Monitoring Update Even A Global Pandemic Couldn’t Stop Bat Monitoring Volunteers From Surveying Bats This Year By Heather Kaarakka bats were from sites that house both which gives a little more evidence DNR Conservation Biologist, little brown bats and big brown bats that bat populations are possibly Bat Program Roost Monitoring or it is still unknown which species stabilizing after white-nose syndrome Coordinator uses the roost. (WNS). Some little brown bat roosts even went from zero bats in 2019 to 10 Like most things this year, the This year’s Great Wisconsin Bat Count to 20 bats in 2020. It’s difficult to say pandemic played a role in how continued although the pre-volancy whether this is evidence of increasing summer bat roost monitoring worked count – the count taken before pups populations or whether bats are in 2020. Social distancing and safer- begin flying (volancy refers to flight) still moving among roosts as we’ve at-home directives meant volunteers -- was delayed until mid-June. Roost discovered that they do quite a bit. could not travel to or gather at monitors surveyed at 90 roosts in We also know there’s no set number several of our large little brown bat June and 125 roosts in July. The first of bats at a roost and bat counts can roosts to count bats and delayed our count in June aims to record adult change dramatically even daily. annual Great Wisconsin Bat Count. colony sizes and the second count in Bat monitoring volunteers are July records numbers in colonies after Little brown bats and eastern resilient, however, and surveyors pups start flying. These differences pipistrelles continue to be the still completed nearly 600 bat in numbers before and after pups fly hardest hit by white-nose syndrome counts at 178 roost sites. Even more can give us a sense of reproduction at monitored bat houses and building impressively, they monitored more in colonies. We see increases in bat roosts. While little brown bats are roosts than ever, adding several numbers at almost every roost site starting to show some evidence of new little brown bat roosts to our (and in acoustics surveys too) after colony stabilization and possibly even database as well as 12 big brown bat juvenile bats begin to fly. See our recovery, eastern pipistrelles were not roosts. infographic below for this year’s observed this year at two of the three numbers and read more about bat summer roosts monitored. This year, In 2020, volunteers counted a total roost monitoring in the 2020 Annual again, summer roost counts of these of 12,844 bats, not so different from Roost Monitoring Report. two bat species mirror low numbers the 13,408 bats counted during 774 recorded on acoustic surveys. We surveys in 2019. Based on the highest 2020 Counts Add To Evidence Bat will continue to watch these known count from each site, volunteers and Populations Are Stabilizing After eastern pipistrelle roosts closely in landowners counted 7,771 little brown White-Nose Syndrome the coming years and hope that we bats, 4,792 big brown bats but only six Like 2019, this year’s bat roost counts see bats return. eastern pipistrelles. The remaining were similar to the previous year,
12 Wisconsin Bat Program • 2021 Study Explores Linkage Between Roost Characteristics & Bat Declines While we were not able to start our A little brown bat snug in a barn project marking bats at persisting in Jefferson County in 2019. colonies this year, we began a Photo: Heather Kaarakka study looking at why there may be differences in declines at little brown bat roost sites. By using yearly colony estimates collected since 2010 by landowners and volunteers at 35 sites, we can investigate the change in colony size year-to-year. From these changes we can learn when the biggest declines occurred and start comparing the roosts using factors such as age of the roost, how close it is to permanent water and distance to hibernation sites. This winter we’re hoping to get an idea of whether there are habitat and landscape aspects that impact how big declines have been and how quickly colony sizes may stabilize after WNS. Thermal Imaging Project Heats Up Another project we were able to to continue another season of daily We’re still analyzing footage, but at pursue in 2020 used thermal cameras counts at several little brown bat one site, bat numbers and behavior to record bat numbers and behaviors. roost sites. We placed cameras later appear similar to last year, which Since these cameras are remote and than we hoped due to the pandemic provides more evidence some little don’t require direct interaction with but also left them later into the fall to brown bat colonies may be stabilizing. landowners or the bats, we were able see colony dynamics in late summer. Thermal cameras allow surveyors to see bats in the dark using heat. The warm bats and their roost are orange and yellow while the cooler background is blue. Right: Three bats are emerging from a bat condo in Trempealeau County.
13 Wisconsin Bat Program • 2021 Thank You For Your Dedication & Information Even a global pandemic couldn’t drives around with a microphone and the impacts that threats like stop bat monitoring volunteers on their car to record bat calls. white-nose syndrome are having from surveying bats this year, and it The information that hundreds of on Wisconsin’s bats. Thank you to reminds us how much the Wisconsin volunteers have helped collect for everyone who surveyed bats this Bat Program has benefitted from the over a decade have opened doors year and at any point since 2008. The dedication and hard work of everyone to research that can help us learn Wisconsin Bat Program would be very who counts bats at roost sites or more about bat biology and ecology different without you.
14 Wisconsin Bat Program • 2021 Wisconsin-Based Research Continues To Illuminate WNS Studies with our research effects of research or census‐ with respect to how WNS partners using data collected in related visitation frequency dynamics and impacts may differ Wisconsin culminated in several on populations. We found no among bat species. Targets for new publications over the past evidence that more frequent visits WNS research were highlighted. months. These results are advancing decreased population growth This tool will be used to maximize understanding of impacts of white- rates for any of these species. the likelihood of achieving bat nose syndrome and informing how we These results indicate that conservation goals within the might support bat populations during visitation frequency (1–3 research context and limitations of specific recovery. visits per year) had undetectable real‐world scenarios. • Results confirmed that bats are impacts on bat population growth Report: Identifying research needs most likely to spread Pd when rates both with and without the to inform white‐nose syndrome they are highly infectious, but additional stress of an emerging management decisions, as seen have reduced mobility and the infectious disease. in Conservation Science and timing of Pd introduction has had Report: Impact of censusing and Practice. consequential effects for some research on wildlife populations, • Diverse microbial skin bat communities. as seen in Conservation Science assemblages, including fungal Report: Mobility and and Practice communities, may prevent infectiousness in the spatial • In our neighboring state of pathogens (Pd) from colonizing spread of an emerging pathogen, Michigan, several banded, male a bat’s skin. Samples collected as seen in Journal of Animal Little brown bats aged 18-25 from bats in Wisconsin were used Ecology (pre-print). years have been recaptured to determine that bat species • Lower levels of Pd in caves in a hibernaculum where WNS with low skin fungal diversity and and mines consistently meant likely has been present since abundance were more susceptible delayed onset of WNS in bats, 2013–2014, indicating that these to WNS than bat species with fewer and less severe infections, old and apparently healthy males higher fungal diversity and and reduced population impacts are in their seventh season of abundance (big brown bats). across regions. Extensive and exposure to the disease. These Report: Skin fungal assemblages persistent environmental findings have been mirrored of bats vary based on reservoirs led to early and by several similar recaptures susceptibility to white-nose widespread WNS presence and at a hibernation site here in syndrome, as seen in The ISME severe population declines. Wisconsin. This gives us hope that Journal. Continental differences in the certain individual bats can live for • Instead of avoiding warm and persistence or decay of Pd in the many years despite the presence deadly underground sites where environment altered infection of WNS in their hibernaculum. the WNS fungus thrives, bats patterns in bats and influenced Report: Exceptional Longevity continue to use them year whether host populations were in Little Brown Bats Still Occurs, after year. Bats are mistakenly stable or experienced severe despite Presence of White-nose preferring sites where fungal declines from this disease. Syndrome, as seen in the Journal growth is high and therefore Report: Environmental reservoir of Fish and Wildlife Management their survival is low. This is one dynamics predict global infection • Using a cross-disciplinary of the first clear examples of patterns and population impacts approach, diverse subject an infectious disease creating for the fungal disease white-nose matter experts created an an “ecological trap” for wildlife. syndrome, as seen in PNAS. influence diagram used to Report: Continued preference • Out of concern that our own identify uncertainties and for suboptimal habitat reduces research and monitoring visits prioritize research needs for WNS bat survival with white-nose could harm hibernating bat management. Critical knowledge syndrome, as seen in Nature populations, we quantified the gaps were identified, particularly Communications.
15 Wisconsin Bat Program • 2021 Diet Study Reveals Bats’ Importance To Ecosystem Little Brown Bats’ Big Appetite Mosquitoes & Ag Pests Beware A single bat can eat the equivalent of half its body weight in insects every night. Amy Wray, UW-Madison PhD researcher, identified, quantified, and analyzed what’s on the menu for Wisconsin bats and why that matters. She found: • Bats consumed 17 distinct types of mosquitoes, including nine species known to carry West Nile Amy Wray, right, and field virus. technician Jamie Wang set • Bats consumed 24 species of up solar-powered traps agricultural pests, including in 2018 to capture the black cutworm moths, night-flying insects bats eat. fruit tree leafroller moths, Photo: Elaine Swanson tarnished plant bugs and spotted wing drosophila. By Amy Wray brown and big brown bat declines • Little brown bats’ smaller University of Wisconsin-Madison from white-nose syndrome. size makes them more PhD Researcher agile and better adapted Different Bat Species for capturing smaller prey. A University of Wisconsin-Madison Eat Different Foods Sadly, these bat species are study examining the diets of bats in Overall, we found that little brown one of the three species in Wisconsin has revealed that different and big brown bats eat different Wisconsin most decimated bat species target different insects prey, with big brown bats eating by white-nose syndrome, a and highlighted the importance of more beetles and caddisflies and deadly disease of bats. little brown bats to agriculture and little brown bats eating more moths • Declines in little brown bats the nocturnal food web. and flies (especially certain types of due to white-nose syndrome midges). These results were mostly may lead to short-term Over a 4-year period, we collected 560 consistent with previous studies on increases in the abundance guano samples to analyze bat diets bat diets in other regions, except of certain insect prey. using molecular methods, captured Wisconsin bats tended to consume and identified 2,003,493 insects in more insect prey typically associated order to quantify changes in bat prey with aquatic habitats. We also found prey, further establishing their communities, and recorded 6,245 that even though insect communities sophistication as nocturnal predators. nights of bat calls to understand changed from week to week, bats changes in bat activity. This study tended to eat their favorite foods Smaller Bat Species Suffer also incorporated roost emergence regardless of the abundance of other Bigger Declines At Study Sites counts from the Great Wisconsin Bat options. These findings suggest that Between 2015 and 2018, we Count, with the goal of understanding both little brown and big brown unfortunately observed little brown the ecological consequences of little bats selectively hunt for particular bat emergence counts decline
16 Wisconsin Bat Program • 2021 Guano samples collected for analysis of bat diets using DNA. Big brown bats have big brown poops Captured insects are sorted before (left) while little brown bats have identification and counting by microscope. little brown poops (right). Photo: Amy Wray Photo: Amy Wray by about 95% at our study sites. see a statistically meaningful decline Similarly, we detected a nearly 80% in low-frequency bat activity, which decline in high-frequency acoustic corresponds to big brown bats but activity around the study sites, includes other species such as hoary which corresponds to little brown bats and silver-haired bats. bats but also includes tricolored bats, northern long-eared bats and Declines In Little Brown Bats May eastern red bats. Based on previous Have A Bigger Impact On Food Web studies and hibernacula surveys, From our insect trapping surveys, these declines in little brown bats we found that between 2015 and are largely attributable to white-nose 2018, the total abundance of insects A Cecropia moth captured in a syndrome. In comparison, we found declined by nearly 50% at our black-light trap was not found in that big brown bat emergence counts study sites. The reason for these the diets of Wisconsin bats. declined by 40%, but this trend was declines is not totally clear and Photo: Amy Wray mainly driven by a decline in a single could represent either a natural large roost which may have been fluctuation or a declining trend after declines from white-nose related to movement rather than to warranting further investigation. syndrome were observed among white-nose syndrome. We also did not However, our study was mainly set little brown bats in Wisconsin. Since up to address how bat population Chironomidae are one of the favored declines influenced the abundance prey items of little brown bats, these of insects, which we investigated results suggest that declines in little by setting up insect traps near bat brown bats may lead to a local-scale roosts and at paired “control” sites increase in the abundance of these further away with lower bat activity. midges. While many studies have shown other bat species controlling When comparing these different insect abundance, including experimental treatments, we found suppressing agricultural pests, our that most insect groups displayed study suggests that little brown bats similar patterns in abundance at may have an impact on other types of sites near bat roosts and at sites insects too. far from bat roosts. As a notable exception, we saw an increase in Little Brown Bats Eat Dozens Of the abundance of Chironomidae, Species Of Agricultural Pests a family of midges, at little brown Since ecosystem services provided bat roost sites compared to control by bats are always important to A black-light trap full of sites. These trends were observed quantify, we also looked at how many Chironomid midges. in 2016 and 2017, the first two years agricultural pests were present in Photo: Amy Wray
17 Wisconsin Bat Program • 2021 bat diets. At least one agricultural some resistance to white-nose as easily. Cumulatively, our studies pest species was detected in 45% of syndrome, could potentially fill provide more evidence that little little brown bat guano samples and in the ecological role of little brown brown bats not only influence prey 34% of big brown bat guano samples. bats as predators. We did this by communities, but also appear to have Interestingly, before declines from comparing diet composition before a unique role as insect predators in white-nose syndrome, little brown and after declines from white-nose the nocturnal food web. In light of bat guano samples contained more syndrome, specifically with the goal bat population declines from white- agricultural pests (53% of samples of quantifying whether big brown nose syndrome and other factors, had at least one pest species) in bats would select more of the prey continuing to protect and support comparison to guano samples previously consumed by little brown bats therefore remains important collected after declines from white- bats. We found that following little from an ecosystem-wide perspective. nose syndrome (16% of samples brown bat declines, there was little had at least one pest species). change in the diet composition of These studies would not have been This change in little brown bat diet big brown bats, and the amount of possible without the support of composition might indicate that dietary overlap between the two bat the DNR, the many volunteers who larger populations of bats are more species also did not increase over contributed to emergence counts, likely to consume a higher diversity of time. While these species may appear and the landowners who allowed insects overall, and therefore may be similar at first glance, little brown sampling of bat guano and insects more likely to eat a greater number of and big brown bats are ecologically on their property. Study sites also agricultural pests. distinct as predators. Little brown included Governor Dodge State bats, with their smaller body size, Park, Yellowstone Lake State Park Little Brown Bats, Hard Hit By are more agile and better adapted and Silverwood County Park, and WNS, Have A Unique Role As for capturing smaller prey. As such, we are most appreciative of their Predators In Food Web big brown bats may be somewhat participation. Finally, we assessed whether big constrained by their larger body size brown bats, which demonstrate and cannot capture smaller insects
18 Wisconsin Bat Program • 2021 Bats With White-Nose Syndrome Prefer Suboptimal Habitats Despite The Consequences Excerpted from Virginia Tech News Sources Since 2006, a fungal disease called white-nose syndrome has caused sharp declines in bat populations across the eastern United States. The fungus that causes the disease, Pseudogymnoascus destructans (Pd), thrives in subterranean habitats where bats hibernate during the winter months. Bats roosting in the warmest sites have been hit particularly hard, since more fungus grows on their skin, and they are more likely to die from white-nose syndrome, according to a new study by researchers at Virginia Tech. But instead of avoiding these warm and deadly sites, bats continue to use them year after year. The reason? Bats are mistakenly preferring sites where fungal growth is high and therefore their survival is low. This is one of the first clear examples of an infectious disease creating an “ecological trap” for wildlife. Dr. Kate Langwig and Dr. Joseph Hoyt, Joseph Hoyt of Virginia Tech gently swabs the forearm of a hibernating Big brown bat in both assistant professors from the 2017 as part of a multi-year effort to understand the impacts of WNS. Department of Biological Sciences Photo: Jennifer Redell in the College of Science, have been studying little brown bat (Myotis “We see that there is a shift across still choosing to roost in warmer lucifugus) populations in Michigan the regional bat population over sites, even though colder sites and Wisconsin since 2012, before the time,” said Skylar Hopkins, a previous are available. But on average, bat fungus first reached those states. postdoctoral scholar at Virginia Tech roosting temperatures have declined, This long-term study was the perfect and now assistant professor at North because the colder-roosting bats opportunity to see if bats alter their Carolina State University. have had higher survival rates.” preferences across hibernacula, or hibernation sites, in response to the “When we look at the population Now that they know that bats are invasion of white-nose syndrome. post-invasion, we see that more preferring high mortality sites, than 50 percent of the bats are Hopkins hopes that their data can
19 Wisconsin Bat Program • 2021 be used to think about which sites about the warm sites that are acting researchers and conservationists as ecological traps and whether we need to prioritize for conservation should be trying to manage those and how to conserve them. sites in a different way. Maybe there are interventions that should be done “Because we know that bats are doing at those si tes to prevent most of the better in the cold sites, the cold sites population from going there each may be good ones for us to conserve,” year and having these big mortality said Hopkins. “We can also think more events.” Doctors Langwig, Hoyt and Kilpat- rick collect samples of the WNS fungus from hibernating Big brown bats in Wisconsin in 2015. Photo: Jennifer Redell
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