Precarious Perch

How this bird and other species struggle to survive our changing environment.
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Precarious Perch

Environmental research at Eastern Michigan University isn’t limited to the laboratory. Faculty members and their students are also out in the field—gathering data, making observations and confronting some significant matters that touch all of us.

Here’s a small sample of significant ecological projects currently underway:

Eastern’s “Batman”

White fright. White-nose syndrome, a fungal disease, threatens two Michigan bat species.

(photo courtesy of University of Illinois/Steve Taylor)

The next time you have a margarita, thank a bat.

Bats pollinate the agave tequilana, a plant used to make tequila that’s grown in Mexico and the southwestern U.S. Bats become dusted with pollen as they feed on the plant’s nectar, then transfer the pollen between plants as they feed and migrate.

“Bats have an important economic impact on farming—not just in tropical areas, but also across the continent,” says EMU Professor of Biology Allen Kurta, whose research is focused on the world’s only flying mammal. “Most North American bats are tremendous insect eaters. A bat mothering its young can take in about 129 percent of its body weight in insects in a single night. Bats help reduce insect damage to crops and the amount of pesticides farmers apply to their fields. Bats also help regenerate forests by dispersing seeds.”

Bats have gotten a bad rap over the years, mainly due to a certain guy in Transylvania (“I vant to bite your neeeeck”). But Kurta says we should ignore those stereotypes and embrace the bat’s unique biodiversity.

“Bats are neat creatures with many unique adaptations, like echolocating,” he says. “They also deliver the largest babies of all mammals. A newborn has about 25 percent of its mother’s weight. Imagine a human delivering a 30-pound baby.”

Although we often see bats flying over our yards at dusk, munching happily on mosquitos and other insects, two types of bats are on the federal list of endangered Michigan species: the Indiana bat and northern long-eared bat.

“Part of my research focuses on the habitat and dietary requirements of these bats,” Kurta says. “My students and I monitor tagged bats to find where they roost and hibernate. Our data provides good bat management information to the Department of Natural Resources and theFish and Wildlife Service.”

Indiana bats hibernate in large numbers in a few caves in Indiana and Kentucky, but their numbers are threatened by human disturbance, including pesticides and the commercialization of caves.

“A door installed on a cave changes air flow and makes the environment too warm for bats,” Kurta says. “They need a temperature of about 40 to 45 degrees for hibernation.” 

The Indiana bat and northern long-eared bat also suffer from white-nose syndrome, a fungal disease that has killed more than a million bats since 2006.

“It’s the most devastating wildlife disease to hit North America since the arrival of Europeans,” Kurta says. “The fungus grows on the face and skin of the bats during hibernation. The syndrome has spread across 27 states and it arrived in Michigan in spring 2014. There is no cure, and the disease is threatening to make the Indiana and northern long-eared bat extinct.”

During the bat hibernation period, Kurta and some of his graduate students visit abandoned iron mines in the western Upper Peninsula to monitor air temperatures and humidity, track the bat population, measure and tag bats, and keep a watchful eye for white-nose syndrome.

“We wear decontamination suits so we don’t inadvertently spread the fungus spores,” Kurta says. “White-nose syndrome presently affects only 5 to 10 percent of Michigan’s bat population, but with each year the problem will grow exponentially. We expect to see 15 to 25 percent affected by the end of this winter.”

Researchers are scrambling to find effective methods of eliminating the disease, or at least halting its progress.

“There are certain volatile organic compounds used for food preservation that may inhibit the growth of the fungus,” Kurta says. “The compounds evaporate in the air, so we don’t have to physically handle the bats.

“The scary part about this problem is we don’t really know how it will impact the environment. The primary predators of nocturnal insects are suddenly disappearing. Will the bat species adapt, or will the insect population explode? Will farmers have to apply more chemicals on their crops? As a bat researcher, it’s really hard for me to see this mass bat mortality. We hope to find a solution before these bats go the way of the passenger pigeon.”

Stress management

 

Survival of the fittest. Red crossbills migrate following bumper conifer cone crops. Red crossbills vary in their plumage color from yellow to red, depending largely on their diet. Shown here is an adult male.

Just as humans need to adjust to climate change and its accompanying environmental stressors, so do birds. But while some birds focus on survival when food is limited, others fail to adapt and starve to death. So what mechanisms enable certain birds to adjust to an unpredictable environment?

EMU Assistant Professor of Biology Jamie Cornelius is looking to two well-adapted species for answers—the red crossbill and the goldfinch.

“Understanding how and why birds respond to changing climate patterns and food availability is central to conservation and environmental management strategies,” she says.

Red crossbills live in northern regions of North America, including Michigan. They feed on seeds within conifer pinecones, and migrate annually as far north as Alaska, following bumper conifer cone crops.

“Conifers produce cones in cycles, so seeds can be present in one region for several years and absent in other years,” Cornelius says. “The variable location of seeding conifers makes red crossbill migration risky.”

Depending on the level of environmental stress, birds are in either a reproduction or a survival mode. Cornelius is studying red crossbill stress levels by implanting the birds with small heart rate transmitters. These devices measure heart and metabolic rates when the birds are engaged in activities like reproducing, migrating and molting (shedding and producing new feathers).

“This study is the first to look at seasonal changes for this species,” Cornelius says. “We can compare the difference between years when they have a lot of food and other years when the food supply is low. We want to know what their baseline need is for reproducing under certain conditions.”

Cornelius and other research collaborators traveled in 2011 to Grand Teton National Park in Wyoming to study red crossbills that breed in all seasons.

“The transmitters emit a continuous tone,” she says. “I stood under a tree with a handheld device that recorded their output. We followed 75 percent of the implanted birds for 24 hours, which was a pretty good success rate.”

Cornelius also made some interesting observations about implanted birds in her lab.

“We limited their food supply or made the supply unpredictable to study their response,” she says. “We noted the crossbills somehow use ‘public information’ to modify their perception of their environmental condition. A bird with limited food is less stressed when it sees that a neighboring bird has abundant food. That’s an important discovery.”

 

Band aid. EMU master's student, Corrie Navis, is taught by EMU
assistant professor, Jamie Cornelius, how to properly band an
American goldfinch.

Eastern undergraduate and graduate students are collaborating with Cornelius by studying another migratory species—the goldfinch.

“These birds breed later in the summer and migrate south in the winter,” Cornelius says. “We want to know what triggers their migration. We suspect stress hormones play a role. As those hormones elevate, so do their active behaviors.”

The students draw blood from trapped birds for hormone analysis. They also measure, photograph and band them before release.

“We trap at several sites across the Ypsilanti area,” Cornelius says. “The birds are stressed but safe. We get an idea of how goldfinches of different age classes are stressed and how that might affect their migratory behavior. And since we band the birds, we can learn how far they migrate if they’re trapped elsewhere.”

Cornelius hopes her findings will help determine which bird species are most susceptible to environmental changes.

“A disconnect between historical patterns of food availability can have a big effect on the bird population, and we’re starting to see declines in a few species of songbirds,” she says. “The red crossbill and goldfinch have already devised mechanisms to deal with an unpredictable food supply. We want to understand the mechanism that helps them adapt to climate change.”

Where have all the flowers gone?

 

Prairie preservation. EMU undergraduate student Dixxon
Darlington collects plant establishment data at a restored prairie.

When European settlers first came to the upper Midwest, prairie fields full of native plants like tall green milkweed, leadplant and white indigo were common. Today, you can hardly find a prairie, let alone a leadplant.

That’s because the settlers plowed the prairies under for farmland, which wiped out the native habitat for dozens of plant species that once thrived in Michigan and other Midwestern states.

“Farmland is not a good habitat for native plant species,” saysEmily Grman, assistant professor of biology at Eastern. “Prairies are dominated by bunch grasses as opposed to turf grasses. A very diverse number of native plants live between those grass clumps. Native prairie plants generally don’t live in the old empty fields you see along the side of roadways.”

Michigan’s few remaining prairie habitats are still being torn up for development. Most native prairie plants aren’t extinct, but many are on Michigan’s list of endangered plant species.

You might think prairie restoration would be as simple as sowing seeds, but it’s not that easy, Grman says.

“There are a number of obstacles,” she says. “Non-native weeds are invasive and can choke out new plantings. Some species may require special soil conditions. The native plants may rely on certain microbes that are missing. Climate change and different weather patterns also make a difference.”

To help sustain this rare ecosystem, Grman is researching the effects of genetic and species diversity on restoring prairie grasslands.

“We’re collaborating with other universities to restore 12 fields in Kalamazoo County covering a total of 35 acres,” Grman says. “We began this fall by changing our seed mixes to vary the species diversity. Some mixes have 10 to 12 species; others have 60 or 70 species.

“We’re also focusing on genetic diversity by planting seed mixes that come from one seed provider, as well as mixes that come from three different providers. We want to see what combination and conditions will enhance our ability to restore native plants.”

Grman’s undergraduate students are assisting by collecting and examining soil samples from those fields.

“We want to identify what germinates on its own from the samples and evaluate how that new growth affects native plant species,” Grman says. “We’re also working with local photographers and other trained volunteers to monitor the butterflies, birds and insects the native plants attract. Prairies support a whole group of organisms.”

Grman’s research differs from past studies in terms of time and scale. Some of the fields studied are up to eight acres, and she expects to monitor them for at least 10 years.

“Prairie ecosystems take a long time to restore,” Grman says. “You can’t even begin to call a field a prairie until two or three years have passed. It can take multiple generations to see results.

“If we care about preserving our environment’s biodiversity for posterity, then our work is important. These native plant species deserve to exist, and we want to help restore them and allow them to thrive.”

Out of sight

 

Have you seen me lately? Fewer sightings may mean the
mudpuppy salamander is endangered.

(photo by Brian Gratwicke)

Mudpuppy salamanders are common to North America’s lakes, rivers and ponds. But unless you’ve gone ice fishing, you probably haven’t seen one in the wild.

“The mudpuppy is native to Michigan and is the second-largest salamander in North America,” says EMU Associate Professor of Biology Katherine Greenwald. “They grow between 8 and 10 inches and love cold water. Some people come across them while ice fishing.”

In recent years, however, ice fishermen have reported seeing fewer mudpuppies, leading researchers to wonder if the species is endangered.

“The mudpuppy population may be suffering, but we need to get a baseline assessment,” Greenwald says. “We’re surveying the Lake Erie to Lake Huron corridor to find where the mudpuppies persist in large numbers. Since they prefer very deep and cold waters during the summer, we do much of our field work during the winter when they’re closer to the surface. We drop baited cylindrical traps through the ice. After trapping, we weigh and measure them and look for injuries.”

Greenwald also takes small salamander tissue samples to her lab for genetic analysis.

“Dams and other human intrusions may cause some salamander populations to be isolated and inbred,” she says. “Then they become more susceptible to all sorts of environmental issues. A new pathogen could potentially wipe all of those salamanders out.

“Since mudpuppies have just scales and skin, they’re incredibly sensitive to environmental contamination. We often see issues with amphibians when there is some sort of environmental problem. Our research could help detect issues that also affect fish, birds and other animals— even human health.”

Greenwald isn’t just focused on the southeast Michigan mudpuppy population. Collaborators across the Midwest, New England and eastern Canada send tissue samples to her for analysis.

“We’ve collected more than 300 samples since launching the project last winter,” Greenwald says. “About 150 to 200 are from Michigan mudpuppies. We’re still analyzing the samples and haven’t made any conclusions.”

A local environmental consultant is assisting Greenwald’s team by placing flat rocks in the Detroit River to restore mudpuppy nesting areas. In the long stretches of concrete riverbed, much of the mudpuppy’s natural habitat for laying eggs has disappeared.

Greenwald is also investigating a new research technique called environmental DNA (or eDNA) to help determine if mudpuppies have been present at a certain site, even when they can’t be seen or trapped.

“Mudpuppies are always shedding DNA into the environment,” she says. “Screening water samples for their DNA could verify presence of the species. If this technique works, we could potentially screen larger numbers of rivers for mudpuppies.”

For now, trapping remains the gold standard for tracking mudpuppies. But one question remains: what kind of bait do they fall for?

“Mudpuppies like certain types of fish, like gobies, and they’re also quite the cheese connoisseurs,” she says with a laugh. “They prefer Colby.”

Contact Geoff Larcom, glarcom@emich.edu, 734.487.4401