UC Research Looks at How Fate of Tiny Lemurs Could Be Linked to Forest Health

Save the lemurs, save the forest ... save the world?

Though extreme, that theory isn't inconceivable to Brooke Crowley, an assistant professor of anthropology and geology at the University of Cincinnati. Her research on forest fragmentation in eastern Madagascar draws upon the connection between

the plight of the native tree-dwelling lemurs and the health of the forests in which they live

.

Environmental consequences of forest loss are not isolated to Madagascar. Crowley believes that her work on this island could have broader implications.

Forest loss could eventually have an effect on the health of the planet

.

"If lemurs are being negatively impacted by human disturbance, then the future of the Madagascar forest in general could be in question," says Crowley, noting the vital ecological role lemurs play in the forest. "At some point this becomes an issue of maintaining species biodiversity, which is an important part of global health. The more we lose, the more precarious food webs are going to become and there's a delicate balance that we're potentially disrupting."

Crowley's research, "

Stable Isotopes Document Resource Partitioning and Effects of Forest Disturbance on Sympatric Cheirogaleid Lemurs

," was recently published in Naturwissenschaften-The Science of Nature, a multidisciplinary science journal based in Germany. Crowley's research is

available on the journal's website

.

Crowley's efforts out of UC's McMicken College of Arts and Sciences support the

UC2019 Academic Master Plan

by producing new ways of understanding and transforming the world through research and scholarship. Contributing authors on this project were Marina B. Blanco of the Duke Lemur Center in Durham, N.C., and the Department of Animal Ecology and Conservation at the University of Hamburg in Germany; Summer J. Arrigo-Nelson of the Department of Biological and Environmental Sciences at the California University of Pennsylvania; and Mitch T. Irwin of the Department of Anthropology at Northern Illinois University.  

MORE HUMANS, FEWER TREES

The human population growth is exploding on Madagascar, and that's a problem for the forests on the island nation off the southeastern coast of Africa. Many of the people who live on the island are subsistence farmers. They use remaining forests to harvest forest products and to feed their cattle, and they use slash-and-burn farming techniques to make charcoal and clear room for crops.

What's left is a gradation in forest quality that Crowley and her colleagues split into three types: pristine, disturbed and fragmented. Pristine forest is vast and healthy with large trees and little sign of human impact. Disturbed forest has been damaged from harvesting by humans and foraging by cattle.

Fragmented forest is not much of a forest anymore at all

.

"When forests are cleared, you get isolated pockets or fragments of forest that are surrounded by open, essentially denuded wasteland," Crowley says.

Madagascar is the only place on Earth to find lemurs in the wild, and the forest is their home. In the present study, Crowley and her colleagues focused on two types of these furry primates: mouse and dwarf lemurs. These small, nocturnal creatures have diets that include some insect matter, fruit, flower nectar and some seeds.

When it comes to feeding, these lemurs are creatures of habit. But

Crowley's research has detected behavioral changes in the lemurs

that live in fragmented forests. She suspects it's a result of the disruption to their habitat.

"Lemurs play a fundamentally important role in the ecology of Madagascar," Crowley says. "The fact that both kinds of lemurs are doing something that's different in the fragmented habitat is compelling. It could be that they have flexible diets and are getting the nutrients they need, or it could be that they're quite stressed and their long-term persistence might be questionable."

FOREST'S FUTURE AT STAKE

Crowley uses a technique called

stable isotope biogeochemistry

to detect patterns in the lemurs' behavior. She puts samples of lemur fur into a mass spectrometer, which burns the fur at super high temperatures in order to measure the amounts of carbon and nitrogen in the samples. The ratios of isotopes in the carbon and nitrogen in the lemurs' tissues help Crowley determine certain aspects of the lemurs' diet and their environment.

Crowley plans to continue collaborating with her co-authors on this research, and she sees their examination of forest fragmentation stemming in two directions. She wants to look more closely at dwarf and mouse lemur behavior across a year's time and investigate how these lemurs are being affected at different stages in their lifespans. But she also intends to expand her research to the larger cousins of the mouse and dwarf lemurs, such as sifaka lemurs, that live in the same forest.

"This research is an important first step," Crowley says. "We can cut down the forest, and it will have the potential to regenerate as long as there is something there to help that happen. If we remove that important player, there's less chance that things will recover."

UC STABLE ISOTOPE LABORATORY

Funding for the university's

stable isotope laboratory housed within the Department of Geology

was provided by the National Science Foundation and the Ohio Board of Regents Action Fund.

CINCINNATI SMART

Crowley's work is among many examples of

Cincinnati Smart

research – where world-class discovery meets real-world clarity.

UC SUSTAINABILITY

Crowley's research aligns with

UC's commitment to integrating sustainability

into its curriculum and all academic and research activities.