On 13 January 2016, the U.S. Fish & Wildlife Service (FWS) issued regulations designed to protect the northern long-eared bat (Myotis septentrionalis), one of several types of bat that have suffered steep population declines because of white-nose disease. The measures constitute an update to interim rules that accompanied a decision last April, which designated the northern long-eared bat as threatened under the Endangered Species Act. The final version of the rule is less restrictive toward timber harvesting; clearing land for wind turbines, houses or oil pipelines; and other activities that might cause some long-eared bat mortality but which the FWS has determined to have no significant effect on the overall population.

On the other hand, white-nose syndrome has killed and estimated 5.7 million bats since monitoring began upon its discovery in a New York cave in 2006. Diseased bats, or the fungus itself, have been detected in 30 states in the Northeast, South and Midwest and in five Canadian provinces. Seven bat species have been affected and the northern long-eared bat is among those hardest hit. The fungus attacks bats that spend winters in caves and mines, disrupting hibernation and depleting the energy their bodies must ration until spring to avoid starvation. It may directly destroy tissue, especially the delicate skin comprising the wings of affected bats.

Inherent in the FWS decision was the decision to list the northern long-eared bat as “threatened” as opposed to “endangered”, a protection category that imposes less-stringent limits on human actions that could harm the animal. The decision has generated criticism from opposite sides of the conservation front: criticism from the timber, oil, and gas industries, which aver that new regulations could boost costs and hamper their work without measurably helping the bats and the potential for an enhanced law suit brought by the Center for Biological Diversity (CBD). Having already challenged the interim rules and especially, the government’s refusal to list the bat as endangered, the environmental group may expand the suit to include the new rules, which “will almost certainly result in more dead bats by allowing the destruction of habitat they need when coming out of hibernation or are pregnant in the summer,” according to CBD attorney Tanya Sanerib. Of particular concern with respect to the ruling is that meta-populations of the long-eared bat have fallen more than 90 percent in some places.

The FWS suggest that the regulations, which take effect Feb. 16, are necessary to protect crucial habitat, including hibernation caves and trees where the bats raise their young during summer. They also argue that the final rule was revised to reduce inconvenience to landowners and industry. According to Tom Melius, FWS Midwestern regional director, “while making it illegal to intentionally kill or harass the bats, [the ruling] keeps to a minimum the prohibitions on harm that happens during otherwise legal projects.”

A spokesperson for the Independent Petroleum Association of America (PAA) said the final regulations were an acceptable compromise. “While oil and gas operations have a negligible impact on the health of the northern long-eared bat, independent producers stand willing and able to comply with conservation measures designed to protect the bat during its most sensitive stages of life,” said Dan Naatz, a vice president of the PAA.

If you’ve got questions about white-nose disease, contact us through our Web site contact page.

The PCCA Wildlife Journal – Weekly Articles on Wildlife, Conservation, & Land Preservation

Copyright© 2016, Pacific Coast Conservation Alliance

White-nose syndrome is a fungal disease caused by Pseudogymnoascus destructans that affects bats. It affects bats primarily in winter when they’re hibernating. Kate Langwig of the University of California, Santa Cruz (along with other researchers) is studying the disease at 30 different sites across North America. Six species of bats comprised her study sample that included winter hibernacula as well as (summer) maternity roosts. At each site, the researchers swabbed bats’ wings and faces and in the lab examined the swabs for signs of the white-nose fungus.

In a recently published article in the Proceedings of the Royal Society B (“B” for its biology edition), Langwig and her group present evidence that bats can successfully fight off the white-nose fungus from about May to mid-October. However, between November and May, when bats head off to their winter hibernacula, white-nose syndrome levels rise steeply. The winter surge appears to be due to two major factors: the conditions within the hibernacula and the bats’ lowered body temperatures.

Regarding the first of these factors, winter roosts, bats typically return faithfully to their over-wintering sites year after year. Once the sites become infected, they stay infected. And the fungus can survive for five years without ever entering its host. That means that a young bat can be free of the disease and become infected at its wintering site – or adult bats may fight off the infection during the summer only to be re-infected in winter when they return to the wintering site.

With respect to body temperature, when bats hibernate, they dramatically reduce their metabolic rate and thus also their body temps, typically somewhere in the range of the ambient temperature of their winter roost (often 15-21°C or 60-70°F). White-nose fungus appears to favor these lower temperatures as well as moisture levels present in many roosts.

How Does White-nose Kill Bats?

Once a bat becomes infected with the disease (by contact with the fungus on a non-organic substrate (e.g., the ceiling of a cave) or through contact with another bat) the fungus feeds off the skin of the infected bat, including its highly delicate wings. By affecting the bat’s metabolism, which attempts to fight off the disease, the bat wakes up more frequently and uses much of its limited fat reserves, often very quickly – and, of course, it’s not feeding during those winter months. Destruction of wing tissue may also lead to disruption of a bat’s water and electrolyte balance. Any or all of these may cause a bats death.

The Good and the Bad News

The bad news, aside from the disease itself, is that there is no current treatment for white-nose disease or an effective way to eliminate the fungus on a broad scale. This new understanding of the dynamics and seasonality of the disease could help scientists develop appropriate countermeasures including the determination of how and when treatments will be most effective.

Based on the study findings, the current timing of treatments is being re-examined. Many efforts focus on treating bats during the fall when they are active. However, it now seems like the timing is inappropriate if the treatment is not long-lasting. Also, treatments may be ineffective once the bats have lowered their body temperatures – the data from this study may provide important clues in terms of development of effective treatments as well as the timing of their administration. The best news is that bats that make it through the winter have a good chance to fight off the infection when their summer activity raises their body temperatures to around 35°C. (95°F), a good 15 to 20 degrees Celsius higher than the conditions that the fungus prefers.

If you’ve got questions about white-nose disease, contact us through our Web site contact page.

Copyright© 2016, Pacific Coast Conservation Alliance

Condensed from an article by Michael Greshko, National Geographic, 17 November 2015

Taglines:
*Bats use a complex social calculus when they share regurgitated meals”.
*Vampire bats remember who has helped them”.

Vampire bats eat only blood—taking small amounts without harming their hosts, which include cattle, horses, chickens, and, of course, native wildlife – and have amassed remarkable biological features to do so. They have unique upper incisors evolved for rasping; they can sense body heat like a pit viper; they can run and jump; and they streamline weight loss from a blood meal by eliminating a blood meals’ water content within 30 minutes of eating – better for flying.

Female vampire bats care for their young for nine months—a long time relative to other bats – and they also help out their colony mates by sharing regurgitated blood with those unlucky enough to score a meal. This is an important behavior since a vampire bat missing two nightly meals in a row is likely to starve. Thus, the behavior is a probable example of reciprocal altruism—helping others so they’ll help you.

The Study
Gerald Carter, a student of University of Maryland biologist Gerald Wilkinson and now a researcher at the Smithsonian Tropical Research Institute in Panama worked with zoos to establish a captive population of several dozen related and unrelated common vampire bats (Desmodus rotundus) at the Organization for Bat Conservation in Michigan. He then observed them for three years, crouching in the bottom of their enclosure with a camcorder sensitive to infrared light.

Vomit Snacks
Carter forced individual bats to fast for 24 hours. He then reintroduced those bats—both males and females—to the group, keeping track of which bats offered vomit snacks to their hungry comrades, recording which bats tended to share their meals with others. When he repeated this trial hundreds of times, Carter noticed that when a fasting female bat had previously shared her food with other females, she received more total sustenance than a selfish one. And some bats refused to help empty-bellied donors who had previously rebuffed them.

Carter also noticed that for many bats, getting denied a snack by an empty-bellied but otherwise willing donor didn’t doom the relationship. He noticed that donors who previously couldn’t give to their hungry neighbors gave even more once they had a meal to share, “just like how you might be especially generous to a friend if you were unable to help them for a long time,” says Carter.

The study suggests that female vampire bats keep track of whom they can turn to in a time of need—and actively work to repair relationships that have gone off-track. “Sharing meals is not just a one-off,” says Wilkinson, who was a co-author on the new study, published November 18 in Proceedings of the Royal Society B. “They integrate [social interactions] over a long period of time.”

Read the full article here.

The PCCA Wildlife Journal – Weekly Articles on Wildlife, Conservation, & Land Preservation

Copyright© 2015, Pacific Coast Conservation Alliance