Endangered Species: Bats

In this installment of KSMU's Endangered Species Series, Michele Skalicky talks with biologists about Missouri's endangered bats.

They're considered nature's pesticides since they consume thousands of insects each night. Bats are beneficial in a number of ways. Here in Missouri, we have about 16 different kinds. All are insect-eaters. Two of those species are endangered in the state: the gray bat and the Indiana bat.

The gray bat, which lives in caves year-round, is doing well today after seeing a sharp decline in their numbers a couple of decades ago. Rick Clawson, resource scientist with the MO Dept. of Conservation, says gray bat numbers have increased over the last 25 years due to protection of the sites in which they roost.

"A number of the important caves that they either hibernate in in the winter or raise their young in in the summer have been brought under some sort of public control, be it a state agency or federal agency, protective fences or gates as appropriate to keep the bats undisturbed while they're roosting in their, and that seems to make a big difference not only in Missouri but rangewide."

The Indiana bat, which lives under tree bark in the summer and in caves in winter, isn't faring as well as the gray. Clawson says it's experienced a long decline, and biologists can't say with certainty why their population has dropped as much as it has.

Lynn Robbins, biology professor at MO State University, says, in the last 25 years, the Indiana bat population has dropped 50% nationwide. In MO, it's dropped over 80%, but it seems to be stabilizing. He says there are some theories as to why Indiana bats are in trouble.

"Recent research, especially out of Bat Conservation International, is indicating that, as the caves warm up, and Indiana bats need very cold winter caves with constant cold temperatures, as these caves warm up the bats may be using more energy during the winter, which is either causing them to move to colder caves or they just come out with not enough energy to complete their reproductive cycle. We don't know exactly, but Dr. Tom Tomasi in our lab has been working on metabolism of Indiana bats to see how the warmer cave temperatures might affect their energy budgets."

It's not all bad news for the Indiana bat. While the situation here in MO for the Indiana bat may be bleak, the larger picture is rosier.

"It ranges throughout much of the eastern United States, and, over the past 25 to 30 years, what we've seen with the Indiana bat is the numbers have increased in parts of the range east of here and north of here while they've decreased in the southern part of the range."

According to Clawson, that appears to be caused by the warm spell ew've had in recent years. The caves in the southern part of the range used to have very high populations of Indiana bats in the 70s and early 80s when the climate was colder.

"Since it's warmed up, I can't say definitively that this is the cause, but the population has shifted and now there are higher populations in caves in Indiana and New York and the northern Appalachians that were lower 25 years ago, well, now they're higher, and our caves in Missouri and Kentucky and other parts in the southern parts of the range, which were much higher in the late 1970s and early 1980s, those have declined."

But Clawson doubts the Indiana bat will ever be completely gone from Missouri. he thinks there will always be some here, and he says it's important to protect the sites that they've historically occupied.

"So that when conditions cycle back, and we can certainly expect that because things don't stay exactly the same forever, that then those roost sites would be available to them and they'll be able to build back up here."

There's possibly a 3rd endangered bat in the state, but Lynn Robbins says it hasn't been seen in MO since the 70s.

"They're starting another search for them in southern Missouri as they get a better idea of what caves they use in western Arkansas and eastern Oklahoma."

According to Robbins, bats are an indication of a healthy environment since they rely on the physical aspects of a habitat and they require a clean water supply to feed over. He explains why bats are so important to our ecosystem...

"The most obvious one is their consumption of insects. They eat huge numbers of insects, and when you have caves with large numbers of bats, it makes a significant difference in insect abundance. People have noticed when they have successful bat houses or even bats in their attic a decline in the insects around their homes. Secondarily, their droppings add nutrients to especially some of our waterways that increase biodiversity in cave life and in adjacent waterways."

If you'd like to help out bats, Lynn Robbins says the first thing you should do is learn about them...

"Most of the problem with any group of animals is lack of knowledge. People tend to fear bats, and I can't emphasize enough that you shouldn't handle bats, especially those that might be in places you don't expect like on the sidewalk or on the floor in your house or porch, but, in general, they will leave you alone. Go out in the evening, watch them flying around, watch how acrobatic they are and get a firsthand view of how many insects they actually are eating in their nightly activities."

And he wants everyone to know that bats aren't any more likely to get rabies than any other wild animal.

The research Robbins is focusing on now has to do with wind turbines.

"It's going to be a good source of fairly clean energy. We're finding now that there is a real negative effect on bats and some birds. They do get killed by the wind turbines."

The research Robbins is conducting is aimed at lessoning the probability that endangered bats as well as other types of bats will be killed. He's looking at things like placement of the wind turbines and when bats are moving through the areas where the turbines are and will be located. Rick Clawson says the MO Department of Conservation, too, is working to help the state's endangered bats by monitoring their populations and trying to figure out what's causing the Indiana bat's decline.

With so many people working to save the state's endangered bats, hopefully their future in the state is secured.

bats squeaking

for KSMU News, I'm Michele Skalicky