Tuesday, April 5, 2011

Young researchers shine during Costa Rican Rainforest Project (Part II)

During the first two weeks of March, Connecticut Audubon Society staff members Frank Gallo and Twan Leenders travel to a Costa Rican rainforest preserve with students and staff from three Litchfield high schools as part of a year-long tropical biology class. Students carry out important research projects, some of which have been ongoing for 19 years. This is part II of a series of blog posts introducing the students, the projects and our results.

Cacho Negro volcano at night - this is the area we worked in for almost two weeks

It is night on a forested volcano in Costa Rica. The forest understory is pitch dark although millions of stars are visible trough small windows in the canopy 100+ feet overhead. The sound of nocturnal animals, birds, frogs and insects mixes with the sloshing of boots slowly walking through deep mud while beams of several flashlights dance around, carefully illuminate every leaf and branch in hopes of finding another hidden gem.

The dense rainforest of Rara Avis preserve provides many places for a small frog or snake to hide

Students Walker Miller, Brandon Turner and Vince Hastings are searching for rare frogs, some of which were almost thought to be gone forever a decade or so ago. A deadly disease caused by a waterborne fungus has decimated amphibian populations worldwide and several species of amphibians have gone extinct in Costa Rica as a result of this global outbreak. For nineteen years I have been studying this disease, the animals it affects and the long-term ecological effects of removing a whole series of keystone species from a complex tropical rainforest ecosystem. Helped by veteran field assistants Alex Shepack, Tim Paine, Don Filipiak and these three high school students we try to find more clues to what is happening with these frogs and all the species they interact with.

You could hide a small dog under one of these leaves!

Although the overall picture is pretty distressing and depressing – a worldwide precipitous decline and widespread extinction of amphibian populations that took place during the relatively short lifetime of my young researchers – there is good news to report as well. In recent years we have been able to document a recovery of several species that were virtually absent from the preserve for almost a decade.

Brandon Turner carefully weighs a small frog

Several streams in the area now reliably yield a call or a glimpse of our target species, while additional populations in areas previously not occupied by these at-risk species are documented each year now too. It appears that several of these species have squeezed through a very tight bottleneck after the initial outbreak of the disease, but slowly their numbers are increasing and they are re-colonizing the areas they were once commonly found.

All animals are measured and relevant data is collected for later analysis

My research over the past decade has shown that the disease is still present in the preserve, but natural selection apparently has favored the few individuals of each species that turned out to be more resistant to this novel pathogen than others in their respective species. These few survivors now form the founding stock of a new, more resistant form of these frogs. Although good news in the short term, the long term survival of these frogs is far from secure.

Walker Miller uses some down time to catch up on data sheets

Global changes in climate patterns are affecting their habitat, invasive plants and animals wreak havoc on ecosystems and loss and alteration of their natural rainforest habitat puts even more stress on these already precarious survivors. However, we’ll take the good news one step at a time and hope that their recovery will be complete some day.

Basilisk Lizards are quite funny!

My new recruits are handling their new found calling extremely well. Most people would never volunteer to head out for many hours at a time into a seemingly endless sea of dense tropical forest. In the middle of the night. Trying to catch frogs, lizards and snakes.

Vince Hastings shows off his newly learned snake handling skills

These three students not only do well at it – they love it! Every hike reveals all sorts of new animals. Individuals are caught, returned to our base camp, identified, measured and weighed, and all data is recorded carefully for later analysis. Animals are photographed and quickly returned to the area where they were found.

Brandon seems pretty at ease too with this 6ft Bird-eating Snake -- this is only day three of the project and these students are working like pros!

After less than two weeks in the field, we documented 60 different species of reptiles and amphibians in the area and hundreds of different individuals were observed.

Strawberry Poison-dart Frog Ghost Glass Frog -- one of our target species!
Crowned Tree Frog - a rare species that only started to increase in numbers two years ago Rufous-eyed Stream Frog - this species can now be found reliably in a few streams in the preserve after a decade-long absence! Many frogs are extremely well camouflaged, like this Clay-colored Rain Frog
No fewer than four new species were added to the preserve’s species list – quite a feat considering that this list represents almost 2 decades of intensive research – and one of those, a small salamander, may actually be a new species to science altogether!
This small arboreal salamander may be a new, undescribed species!
Canopy Lizard

Carpenter's Anole

Future research will hopefully tell! For now we can leave the preserve behind, knowing that at least a few of these rare species are not quite extinct yet and are seemingly maximizing their second chance at life.

One of the new additions to the reserve's species list: White-headed Snake
A Lichen-colored Snail-eater
Orange-bellied Glasstail
Central American Coral Snake
Hognose Pitviper
A surprising caterpiller, whose rear end is trying hard to look like a snake!
The Rainforest Project's Amphibian and Reptile Team

If you would like to learn more about Twan's research on endangered amphibians, please come see his talk on Wednesday April 6 at 7PM at the CAS Coastal Center at Milford Point, or come see the student’s presentation during dissertation day on April 28 (more details to follow on that).

All photos copyright Twan Leenders

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