ADVERTISEMENT
  About the SA Blog Network













Expeditions

Expeditions


Field notes from the far reaches of exploration
Expeditions HomeAboutContact

Problems Without Passports: Scientific Research Diving at USC Dornsife–The Endangered Endemics and the Aggressive Invader


Email   PrintPrint



Guam is 17 hours ahead of Los Angeles, and even our USC students were up early (or at least on time) for our first morning in Micronesia. After a generous and very international buffet breakfast in the Hilton we walked out into intermittent squalls and boarded our charter bus to the Guam Department of Agriculture. There we were met by Dave Ginsburg’s long-time friend and colleague, Brent Tibbatts of the Division of Aquatic and Wildlife Resources.

Pictured: Senior environmental studies major Raquel Rodriguez holds a ko’ko’ (Guam Rail) as other students in our course gather around. By Jim Haw.

This first morning on Guam was devoted to threatened and endangered terrestrial species. For millennia, Guam was devoid of predators. The Guam Rail, a flightless bird locally known as the ko’ko’, thrived. But not long after World War II, a gravid brown tree snake—a viper native to Papua New Guinea and coastal Australia—entered Guam with a cargo shipment. With almost no predators, and an abundance of birds indifferent to the snake such as the ko’ko’, its population exploded at the expense of the birds.

The ko’ko’ was further threatened by feral cats, human consumption and habitat loss. By the time a conservation effort was organized in the 1980s, only 10 individuals could be found, from which all surviving ko’ko’s are descended.  Currently the Division of Aquatic and Wildlife Resources is breeding 107 ko’ko’s in captivity, and small populations have been reintroduced into several locations in Micronesia.

Left: One of the last two Mariana crows on Guam morns the death of his mate a few days earlier while perched in his enclosure. By Jim Haw.

We saw two other critically endangered bird species at the Guam Department of Agriculture. Modeling studies suggest that the Mariana crow will likely become extinct later this century. In fact, the last female Mariana crow on Guam died on Friday, leaving her mate, who we saw, in obvious distress. He might be moved to another island to be paired with a female there. 

We also saw Guam Micronesian Kingfishers, a species of bird that survives only in a globe-spanning network of captive breeding programs at zoos and at the Department of Agriculture.

Wildlife biologist Suzanne Medina introduced our students to a ko’ko’ who is more accustomed to being handled by humans. Our students immediately fell in love with the bird.

Right: Guam wildlife biologist Seamus Ehrhard (left) introduces a venomous brown tree snake to Kim Knabel, a double major in environmental studies and environmental engineering. By Jim Haw.

Not to be outdone, Seamus Ehrhard, another wildlife biologist, brought out a 6-foot brown tree snake for us to see and handle. This snake is a viper, but its fangs are in the back of its mouth, and injecting its venom into humans typically requires chewing rather than a simple strike.

Adult humans, when envenomed, usually experience mild symptoms—little worse than a bee sting. Nearly all of our students interacted with the snake, some immediately and others with a little bit of hesitation. This encounter was under the control of a professional wildlife biologist. Uncontrolled, the brown tree snake has a reputation as an aggressive animal—quick to strike, and strike and strike again.

Left: Wildlife biologist Suzanne Medina introduces one of the last eight remaining Guam fruit bats to the USC students. By Jim Haw.

The last animal we interacted with might be one of the most endangered mammal subspecies in the world. The Mariana fruit bat is listed as threatened by the U.S. Fish and Wildlife Service, with most of the remaining individuals on several of the islands in the northern Marianas.

The Guam Mariana subspecies has 8 remaining individuals, 7 in the wild, and a single captive male rescued following a typhoon some 14 years ago. Suzanne brought out this individual for us to observe, but handling the bat requires special attention as it can bite. Human consumption, brown tree snakes, other invasive species, habitat loss and possibly disruption of resting sites by aircraft noise have all but wiped out this beautiful creature.

Of the threatened animals we met, the ko’ko’ has the best chance of survival because it can produce several egg clutches per year, and the survival rate of young birds is reasonably high. Advances in captive breeding strategies must be found for the Guam Kingfisher, or this species will soon be gone.

On the nearby island of Rota people are apparently deliberately killing some of the remaining Mariana crows, and this species could soon be lost from the wild or entirely. One of the best potential habitats for preserving the crow in the wild is on U.S. Air Force property on Guam, but the U.S. Department of Defense prohibits the reintroduction of endangered species onto their property.

There is no hope or expectation that the Guam subspecies of the Mariana fruit bat will recover. The brown tree snake however remains plentiful, and it is blamed for many of the numerous power outages on Guam, some indeed caused by the arboreal snake shorting out power transmission lines.

For our students, the value of today came not only in bearing witness to animals that will likely become extinct in their lifetimes; it came in meeting selfless and hardworking professionals such as Brent, Suzanne and Seamus who are trying to make a difference—whatever the odds against them.

About the Author: Dr. Jim Haw is Ray R. Irani Professor of Chemistry and director of the Environmental Studies Program in the USC Dana and Dornsife College of Letters, Arts and Sciences. He is also a scientific, technical and recreational diver.

Editor’s note: Scientific Research Diving at USC Dornsife is offered as part of an experiential summer program offered to undergraduate students of the USC Dana and David Dornsife College of Letters, Arts and Sciences. This four-week course takes place on location at the USC Wrigley Marine Science Center on Catalina Island and throughout Micronesia. Students investigate important environmental issues such as ecologically sustainable development, fisheries management, protected-area planning and assessment, and human health issues. During the course of the program, the 24-student team will dive and collect data to support conservation and management strategies to protect the fragile coral reefs of Guam, Palau and other Micronesian islands.

Instructors for the course include Jim Haw, Director of the Environmental Studies Program in USC Dornsife, Environmental Studies Lecturer Dave Ginsburg, SCUBA instructor and volunteer in the USC Scientific Diving Program Tom Carr and USC Dive Safety Officer Gerry Smith of the USC Wrigley Institute for Environmental Studies.

The views expressed are those of the author and are not necessarily those of Scientific American.

 





Rights & Permissions

Add Comment

Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.

More from Scientific American

Scientific American MIND iPad

Give a Gift & Get a Gift - Free!

Give a 1 year subscription as low as $14.99

Subscribe Now >>

X

Email this Article

X