By Chris Powers
SC Staff Writer
Stefani Cannon, a graduate student working in the Biology Department at East Stroudsburg University with Dr. Thomas LaDuke, recently spent her first field season studying frogs in Costa Rica.
Cannon came to ESU in 2013. She said, “For undergrad, I graduated from Bloomsburg University with an environmental degree in 2013.”
According to Cannon, she came to ESU because she really enjoyed interacting with all of the professors and they had a lot of unique projects for graduate students to work on.
Cannon said, “I really liked working with species interactions, but I didn’t have a specific project in mind.” Cannon met with many of the biology professors, such as Dr. LaDuke, Dr. Master, and Dr. Whidden.
When deciding on a graduate advisor, Cannon said, “I went with Dr. LaDuke because… he brought up the idea of working with tree frogs in Costa Rica, and it seemed really interesting to look at the differences in how the frogs are using different plants to shelter on.”
Cannon said her project “is looking at niche partitioning in tropical tree frogs in the lowlands of Costa Rica, such as where the frogs are finding shelter and finding a place to sleep during the day.”
According to Cannon, you can find tree frogs in a wide variety of habitats.
She said, “For a lot of tree frogs, you will find them on the top of leaves or underneath, just kind of suctioned to the leaves. They blend in because a lot of them are green, and a lot of other tree frogs we were finding in rolled up leaves.”
These rolled up leaves are important to look at because they can only provide shelter for a few days before the frogs mature and spread out into a more traditional structure.
Cannon’s trip was mostly self-funded. She said, “I applied for a few grants, but I didn’t get a lot of funding, so it was mostly my funding and Dr. LaDuke helping me get down there.”
Before actually starting her field season, Cannon took a separate trip to Costa Rica as a part of ESU’s Biology of Tropical Ecosystems class.
She spent a good deal of time at El Zota Biological Field Station, which would later become her home during the summer.
Cannon spent much of her summer there, saying, “I went down in the beginning of June and I stayed down there until mid to late August.”
She mentioned, “I was at El Zota the whole time in a secondary forest, and not a whole lot in the primary forest.”
A secondary forest is a forest that has been more recently cut down or disturbed than a primary forest, which stands relatively undisturbed for long periods of time.
There is a primary forest present at El Zota, but, according to Cannon, “Hiking to the primary, six miles every day there and back takes a lot of time, which is pretty valuable when you are down there because you only get twelve hours a day of sunlight.”
Cannon had specific areas of the forest that she would survey. She said, “I would set up 50 by 10 meter plots, and I would survey each plot 10 times.”
Cannon originally had 20 of these plots, but one of them was lost due to deforestation.
According to Cannon, in the actual sampling, “I had five to six running at any given period and I would just kind of cycle through them. I ended up with nine total species of tree frogs and 59 total individual frogs.”
With these nine species, Cannon said, “We pretty much saw every type of tree frog we expected to find.”
She also noted, “When I found them, I did my best to leave them how they were.”
There was a variety of different parameters measured about these frogs.
Cannon said, “When I found a frog, I had two different categories: leaf sitters, which sat on top of the leaves or underneath, and leaf dwellers, which were found living inside the leaves.”
After recording the category, there were a number of leaf measurements, such as the orientation of the leaf, how high off of the ground it was, how far from water they were, leaf length, leaf petiole length, and a variety of other parameters.
After these metrics were taken, Cannon said, “We did a quick vegetation survey. We would center the frog on a five by five meter plot and do a vegetation survey of that five by five meter plot.”
The point of taking all of this data, according to Cannon, was to “give us an idea of where these frogs were choosing their habitats, if there was a difference from one species to the next, or even from an individual to the next.”
Another important metric was whether or not the frogs utilized the same location more than once.
Cannon said, “After we found them, we went back to see if they were there the next day and we found that they weren’t, which was surprising because we expected that the leaves would be a pretty valuable resource, but I didn’t find that happening.”
Cannon wants to finish her work at El Zota next summer. She said, “I am trying to go back this summer for my second field season. I have been applying for some grants and I hope I can get some more funding for this season.”
Cannon saw a huge variety of wildlife not seen by ordinary tourists in Costa Rica.
She said, “The coolest thing I saw at El Zota was a tapir. I also saw two Agalychnis callidryas and two Amplexus laying eggs all in the same night, within an hour and a half.”
Cannon’s experience from this summer has been invaluable to her.
She said, “I want to say it was the experience of a lifetime, but I hope to go back for a second field season next summer.”
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