On March 11, hikers found the sick bat about 30 miles east of Seattle near North Bend, and took it to Progressive Animal Welfare Society (PAWS) for care. The bat died two days later, and had visible symptoms of a skin infection common in bats with White Nose Syndrome. -U.S. Fish & Wildlife Service.
This comes across as incredibly serious and dire news for educators, government workers, and bat enthusiasts along the west coast. But if you have never heard of white-nose syndrome (WNS), or even knew we had bats in the North Cascades National Park, you might not know how or why this is dire.
What bats live in the National Park?
There are eight species of bats that reside in the park. The first belong to the genus myotis (meaning mouse-eared) and the second three are larger and belong to other genus’s.
- Long-eared myotis (10-11 in. wingspan) are named after their exceptionally long ears and have great flying maneuverability.
- California myotis are one of the smallest in the park (8-10 in. wingspan) and can only detect insects with echolocation at a very close range.
- Yuma myotis (8-10 in. wingspan) hunt over water and fly in the direction of the current (straight if rivers, circles if lakes).
- Long-legged myotis (8.5-10.5 in. wingspan) are named after their longer hind legs and have been found at elevations up to 3,500 ft.
- Little brown myotis (8-11 in. wingspan) are one of the most common bats across America and are often confused with yuma myotis.
- Hoary bats are the largest in the park (13-16 in. wingspan) and are named after their hoary, or frosty, coloring.
- Big brown bats (8-15 in. wingspan) are habitat generalists and can have maternity roosts from a few dozen to several hundred.
- Silver-haired bats (7-14 in. wingspan), along with hoary bats, have the longest migratory paths of species in the park.
How do bats live in the park?
Being found throughout the world except Antarctica, bats (order Chiroptera) have the second most number of mammal species known, after rodents of course. While other mammalian species have been shown to glide (such as the flying squirrel), bats are the only mammal that has the capacity to truly fly. Bats are generally divided into two families: the large fruit eating “flying foxes” and the smaller echolocating insectivores. Some species from each group also eat nectar which helps to pollinate the local ecosystems. However, none of the bats located in the park have been found to eat nectar in any way and are echolocating insectivores.
The life cycle of a bat starts in early winter when most mating is done. Females delay fertilization throughout hibernation, and begin gestation in spring. For the smaller bats in the park gestation lasts for 40-60 days while the larger hoary bats take 90 days on average. Litters consist of one pup, and on rare occasion have twins. Hoary and silver-haired bats, however, usually have two and have been documented on having up to four! First flight for the little pups take between 2.5 and 4 weeks, and start hunting after one to two months. Some bats can bred in their first year, with lifespans ranging anywhere from 15 through 30 years! They then start the cycle all over again in early winter.
To prepare for their winter hibernation, the bat species in the park eat at least half their weight of insects each night. Foraging begins from just before sunset and into the night. Most species hunt for a few hours, rest for an hour or two, and then hunt again. These sessions continue until just before sunrise. To capture these insects, bats use echolocation. While bats are not blind, echolocation increases their success rate immensely during their peak hunting times. To get an understanding on how this works, imagine yourself in your own home. Light is traveling from the ceiling, hitting objects, and then traveling into your eye. Your brain then calculates where and what is around based on those light patterns. Instead of using light, bats use sound. They emit this sound constantly, hitting all that is in front of the bat. When the sound bounces back, the brain of the bat calculates what is it and how far away it is. They also use echolocation to avoid predators when possible, such as owls and hawks.
During this summer hunting time, bats roost either alone or by sex (depending on the species) during the day to rest. Some roosting spots include caves, buildings, rock crevices, and beneath loose bark in trees or even on branches. During the night foraging bats find a roosting location that is close to their preferred hunting habitat. When bats hibernate they use hibernacula, or winter roosts. Usually more sheltered than their summer counterparts, these roosts need to insulate heat and protect the individuals against predators. In the Pacific Northwest, most species do not hibernate in large groups except for the little brown and big brown bats. While they share flight with birds, most bats do not migrate more than a dozen or so miles from their summer hunting grounds with the exception being again hoary and silver-haired bats which migrate all the way down to Mexico for the winter.
Why are bats important for the park?
Each species plays an important role in the overall ecology of the park. While the whole ecosystem of the park would not cease to function, any small change in the whole system can have unseen consequences for years to come. The roles of these species in this park can be surmised as insect control, nutrient distribution, and a bioindicator of ecosystem health.
All of the bats in the park are insectivores, consuming a large number of insects. For example, the little brown bat weighs only 7.9 grams but needs to consume 9.9 grams of insects each night! It is eating more than it’s body weight each day to recuperate from the winter and store fat for next hibernation. Without these two species, there would be an increase of insect activity, which in turn could harm local vegetation and pester natural fauna. An estimated 99% of potential crop pests are controlled in part due to bat activity.
After all of that insect mass is digested, bats spread the nutrients around the ecosystem through guano. Because bats transfer roosting spots often during spring, summer, and fall, their guano is spread evenly throughout their range providing nutrient cycling. This fresh fertilizer helps producers, like trees and ferns, as well as providing nutrients for decomposers, like fungi, bacteria, and arthropods.
A biodindicator is a litmus test for the ecosystem. If the overall system is healthy enough for bats, for example, then we know it is healthy enough for the insects that are consumed. Bats are sensitive to stressors, like climate change, and their absence could predict things like pollution or water acidification. With bats dying to WNS, the park has one less “litmus test” to see how climate change is impacting the overall system.
Now that we know which bats live in the park and their ecological significance, we can dive into white-nose syndrome.
What is white-nose syndrome?
The first case of white-nose syndrome (WNS) in the U.S. occurred in February, 2006 in Albany, New York. Researchers documented a white substance around the muzzles, ears, and wings on both alive and dead bats in the Howes Cave. Upon further investigation it was discovered that the substance was a fungal growth ofPseudogymnoascus destructans (formerly Geomyces destructans). The fungus colonizes best on thinner outer tissue of bats (nose, ears, wings), eroding the skin and thriving off of inner-connective tissue. To date, it is thought that over six million bats have died to the syndrome in North America.
While the exact cause of death is uncertain, scientists hypothesize that the fungal growth disrupts their hibernating habits. Deceased bats with the syndrome have been reported with having significantly lower body weight compared to the population average at that time of year. When bats hibernate in cool, damp places over the winter P. destructans infects the bats. Whether awake or asleep, this added stress causes bats to use fat storage at a faster rate than normal. If a bat wakes up it will most likely not be able to find a food source at that time of year and die of starvation.
WNS is not exclusive to North America. P. destructans is found widespread over Eurasia, causing bats of the region to also have the characteristic “white muzzle.” Eurasian bats, however, are not dying from the syndrome. Just like diseases caused mass extinctions of native populations in humans during European conquest, Eurasian bats have co-evolved with the fungus and therefore are not dying out. North American species, just being introduced to it this century, have not developed a resistance and are dying in mass.
Since 2006, the syndrome has been slowly spreading west, south, and even north into Canada. Taking a decade to reach a third of the way across the country, scientists on the west coast were preparing for the disease, expecting it to come before 2030. On March 11, 2016 in the Cascade Mountain range hikers found a dying little brown bat (M. lucifugus) on the trail and took it to an animal shelter for help. After two weeks of tests it was discovered to have the presence of P. destructans. On March 31, 2016 the U.S. Fish & Wildlife Service informed the public about the first confirmed case on WNS in any western state.
What is being done about it?
The severity of WNS has caused states, federal agencies, universities, and non-profit organizations to combine resources continent wide. US Fish & Wildlife is the main stakeholder, creating a seven-part plan to organize all partners. Each team responsible for one part of the plan is critical to understanding and managing this national epidemic.
- Communication and Outreach: The first step towards a solution is education. This team is responsible for sharing resources and results with partners and the public. Through a dedicated communications and outreach team, new information and best practices involving management and education can be spread like never before.
- Data and Technical Information Management: Data management can be as unruly as fungal diseases without a dedicated team. Responsible for synthesizing and tracking data, this team updates a database so that partners nation wide can see progress in clear ways.
- Diagnostics: Part of that data collected is fully dedicated to consistent updates of the disease. This team is responsible for creating standards that researchers will use to monitor the fungus. Always updating with best methods, they will adapt to see what management practices are working.
- Disease Management: The fungus P. destructans could easily be killed with fungicide. However, such extreme measures could in turn harm more bats and the surrounding ecosystem. This team is responsible for finding ecologically sound methods of containment and removal without causing more ecological harm.
- Etiology, Epidemiological, and Ecological Research: Over the past decade research has been a cornerstone for finding patterns and breakthroughs to WNS. Responsible for research of both bats and P. destructans, this team provides raw data that can be transferred into the field.
- Disease Surveillance: Working on the ground, this team is responsible for collecting data on what the disease is doing. Early detection, like what was found in Washington State, is critical to responding as fast as possible.
- Conservation and Recovery (of Affected Bat Species): With such a large stressor, bats more than ever need large conservation efforts to have any chance of success. This group creates and implements conservation protocols so that no additional stressors are being placed on bat populations.
Can I help?
Absolutely! While the US Fish & Wildlife plan for dealing with WNS is massive, the public body needs to participate in conservation efforts to achieve best results. Many factors such as lack of knowledge and financial resources could initially alienate the public from such efforts. However, most public participation can be extremely beneficial with even the smallest amount of education, conservation, and construction.
- Education: Humanity has created many misconceptions about bats over the centuries. The majority of the public does not have an opinion on bats at best and view them as a pest at worst. With just one resource or two, most of those misconceptions can be transformed into correct knowledge about these amazing creatures. Either through workshops, festivals, or even online research, the public has more access than ever to reliable information on bats.
- Conservation: Along with education, there are multiple conservation efforts that the majority of the public can be involved with. First, the public should not disturb habitat. Most natural hibernacula are either blocked off with signs or so remote that public access is impossible. If anyone finds bats resting they should immediately leave as to not put more stress on the bats. After walking through any hibernacula it is important to immediately bleach all equipment as to avoid accidental spread of WNS. Second, the public should report anything unusual. If a bat is walking outside during winter, or if any bat is found dead on the trail, it should be reported immediately to the nearest authorities so that action can happen as soon as possible. Third, volunteer! There are plenty of opportunities to help organizations with data collection and conservation management. This is a great way to gain exposure to bats in the safest way possible.
- Construction: Interaction with local bat species does not end when leaving the park. In every neighborhood there is a possible bat population that needs as much help. Constructing bat-boxes is a cheap method for providing habitat for bats, even in sub-urban areas. Most bat-boxes can be constructed for less than $30.
If you want to keep up to date on all things WNS, check outwhitenosesyndrome.org. It is the go to resource on the spread and prevention on this disease.
Species photos courtesy of:
- Long-eared myotis, retrieved from scbats.org
- California myotis, taken by Rob Schell. Retrieved from fieldherpforum.com
- Yuma myotis, taken by Dick Williams. Retrieved from batrescue.org
- Long-legged myotis, retrieved from falconservices.com
- Little brown myotis, retrieved from batworlds.com
- Hoary bat, taken by Merlin Tuttle. Retrieved from batsaboutourtown.com
- Big brown bat, taken by Liam McGuire. Retrieved from lpzoo.com
- Silver-haired bat, retrieved from nature.org