Volume 19, Issue 3, Fall 2001

BCI Research Scholars:

Making a Difference for Bat Conservation

By C. Geiselman & E. Acker

Since 1990, BCI has awarded 132 scholarships supporting students in conservation-relevant research in 33 countries. Wide gaps in scientific knowledge about bats are often roadblocks to conservation, and these student scholars, including the five featured below, are helping pave the way for future conservation efforts. Their projects also help BCI build lasting relationships with local communities that, through the students’ education efforts, learn to value bats as essential allies.

Bats in Northwestern U.S. Forests
Ed Arnett
Oregon State University
Scholarship Recipient 2000 and 2001

Ed Arnett is a doctoral student in forest ecology at Oregon State University. He is researching the impact of snags and other potential roosts on bat abundance and habitat use in managed forests of the Oregon Cascades. This information will help improve forest management practices for bats. “We’re trying to develop models that will help forest managers better predict how their decisions affect bats,” said Arnett. “This includes developing strategies to help managers ensure a continuous supply of roosts, primarily by leaving snags and live trees of varied size and age, in areas most suitable for bats.”

Twelve species of bats occur in Douglas-fir forests of western Oregon. Nine of these roost in tree cavities and crevices and play important roles in consuming insect pests that attack forests. Arnett’s research centers on the roosting preferences of three species: big brown bats (Eptesicus fuscus), long-legged myotis (Myotis volans), and long-eared myotis (Myotis evotis). Using radio telemetry techniques, he has tracked these bats to their roosts in 36 landscapes that include a wide range of habitat (snags).

To date, more than 460 roosts have been identified, an unprecedented sample size, and a clearer picture of bat communities has begun to emerge. Long-eared myotis use snags, downed logs, rock outcrops, and stumps, but use snags more frequently when they are available. Big brown bats and long-legged myotis prefer snags and large trees with woodpecker cavities or broken tops in all landscape conditions. Also, it appears that the availability of structures used as roosts is more important to bats than forest age.

A diversity of partners, including federal and state management agencies, private industry, conservation organizations, and private foundations are collaborating to support this study. Arnett has also led cooperative efforts within the timber industry. “In recent years, private companies have become more involved in wildlife research and have focused on studying habitat relationships to help integrate the needs of wildlife, including bats, in forests managed for paper and wood products,” said Arnett. “Large, cooperative studies are critical to amassing the data necessary to answer complex questions about bats’ needs. Final results of Arnett’s study will be available in December 2002.

Bats, Pests, and Pears
Natasha Walton
California State Polytechnic University
Scholarship Recipient 2000 and 2001

Natasha Walton has always been fascinated by wildlife, receiving her undergraduate degree from the University of California at Davis in Wildlife and Fisheries Biology. However, it was Dr. Merlin Tuttle’s article in National Geographic in 1995 that piqued her interest in bats. “I tend to be interested in animals that other people shy away from,” she said when asked how she decided to work with bats. Upon returning to graduate school at California State Polytechnic University in Pomona, Walton began studying Mexican free-tailed bats (Tadarida brasiliensis). “I’m working with a colony of approximately 6,000 bats that lives in the Iwama Market, a vacant building, in Suisun,” said Walton. She is studying the effects of their voracious appetites on the codling moth (Cydia pomonella), the main insect pest in nearby pear orchards.

For her Masters thesis, Walton is working with local growers in Suisun Valley using their orchards as her study sites. At dusk every evening she assembles her bat monitoring stations, consisting of bat detectors connected to appropriate recording equipment, in orchards close to and far away from the bat colony. She then returns in the early morning to collect data on bat activity. She also deploys pheromone traps to determine codling moth numbers in each orchard and collects pears at each study site to evaluate moth damage. On some evenings, once each study site is set, Walton either observes the emergence of the bat colony at the Iwama market or visits orchards to personally observe feeding bats flying through the trees.

Her study will not be complete until fall 2002, but Walton has documented bats using pear orchards as feeding grounds and suspects more could be attracted through use of artificial roosts, potentially good news for pear growers who are constantly suffering losses from codling moths. Already stressed by low market prices, any natural control of this leading pest can have a significant impact on financial profitability. Pear orchardists and bats may soon be
recognized allies.

Walton has shared her preliminary findings with local growers and as a result, some have already begun installing bat houses to encourage bat colonies to live and feed in their orchards. Local school groups have organized field trips to the Iwama Market to watch the bats emerge in the evenings and, through Walton’s education efforts, they and the local community are learning more about their bat neighbors. As Walton completes her study and analyzes her data she will continue to educate local farmers, teachers, and children about California’s bats, their needs, and the benefits of helping them.

Conserving Subic Bay’s Flying Foxes and Rain Forests
Tammy Mildenstein and Samuel Stier
University of Montana at Missoula
Scholarship Recipients
1998 and 1999

Tammy Mildenstein and Samuel Stier, both graduate students at the University of Montana at Missoula, are two-time BCI scholarship recipients. As Peace Corps volunteers from 1999-2001, they were assigned to help officials at the Subic Bay Metropolitan Authority Ecology Center in Subic Bay, Philippines, promote environmental conservation in the 24,710-acre (10,000 hectare) area that once housed the largest overseas U.S. Naval Base. Since the 1997 Southeast Asian economic crash, there have been increasing pressures to create a Duty Free Zone on the base in hopes of bringing more money into the country. However, with 98 percent of the Philippines’ original forests lost to logging, this parcel of land is ecologically important as the last tract of lowland, old-growth monsoon forest in the entire country. It is also home to a colony of 20,000 endangered Philippine giant (Pteropus vampyrus) and golden-crowned (Acerodon jubatus) flying foxes.

“This bat colony, due to its ecological, economic, and educational importance, has become the focal point of a community-wide conservation effort,” said Mildenstein. “With such a singular resource, officials from the Ecology Center have been eager to set up a management plan for their popular, but endangered, bats. The roost area is protected from hunting during the day, but conservation officers can not protect the bats at night without knowing where they go to forage.” The entire Subic Bay Protected Watershed is under pressure to allow industrial developments to displace valuable forests. The Ecology Center could only justify a denial of development requests in the forest if it could prove that the area was important to endangered wildlife. More research was essential.

In order to document where these fruit bats forage, Mildenstein and Stier captured 13 individuals and attached radio transmitters before releasing them. They trained a team of wildlife biology students, Ecology Center staff, indigenous people, and local bat hunters to help them track the bats and record their foraging locations throughout the night. Later, the locations were plotted on a map and visited by day so that each site could be described in terms of habitat type and vegetative and structural characteristics thought to be important for the bats.

While the data is still being analyzed, preliminary findings suggest that the fruit bats are primarily dependent on undisturbed rain forest, especially along waterways and in areas with a high density of “bat trees.” (The couple determined which trees were used as flying fox food resources by identifying seeds in their droppings.) Officials at the Ecology Center are now developing a management plan around these findings ensuring the bats’ future protection. Thanks to the experience and training gained, the eight field assistants who helped with the project have all gone on to use their new skills for bat conservation. Mildenstein and Stier have also forged partnerships with Shell Oil and a local hotel to promote habitat restoration and ecotourism.
Industry and tourists alike are learning that flying foxes are vital ecological links as pollinators and seed dispersers in the rain forest ecosystem. Thanks to the student scholarship program, many people are learning to value and protect flying foxes as a uniquely valuable resource.

Bats in America’s Majestic
Redwood Forests
Danielle Purdy
Humboldt State University
Scholarship Recipient 2001

Due to intensive logging and development, old growth redwood forests now cover less than five percent of their original range. With such losses, scientists are just now beginning to understand the importance of these trees as shelters for wildlife, including bats. Armed with a BCI scholarship, Danielle Purdy is studying bat use of these mammoth trees in order to gain a better understanding of their importance as roosts.

As a student in the Department of Wildlife at California’s Humboldt State University, Purdy is currently pursuing a Master of Science in Natural Resources. She works on the northern coast of California, near Arcata, where California myotis (Myotis californicus), long-eared myotis (Myotis evotis), Yuma myotis (Myotis yumanensis), and other species are known to roost beneath bark and in large cavities, also known as basal hollows, in old-growth redwoods. Basal hollows form when wood at the base of a tree decomposes following exposure to intense fires. Purdy hopes to document which species use these ancient hollows by collecting droppings and by mist-netting bats in and around the trees in the evenings. Using the data collected, she will compare use of contiguous forests in state parks to that of private, heavily logged timberland. The outcome of this comparison will assist forest managers in considering the needs of local bat populations before proceeding with logging activities.

This study grew out of Purdy’s personal interest in bats and the experience she gained through participating in one of BCI’s Bat Conservation and Management Workshops (see workshop schedule page 12) in Barree, Pennsylvania. She was delighted to meet other people who shared her interest, and was able to learn many of the study methods she now uses. Following completion of her degree, she plans to teach biology and share her enthusiasm for bat conservation.

All articles in this issue:

Stay up to date with BCI

Sign up and receive timely bat updates

BCI relies on the support of our amazing members around the world.

Our mission is to conserve the world’s bats and their ecosystems to ensure a healthy planet.

Please join us or donate so our work can continue.