When we reached the stream, I hopped out. I walked to the streams bank and started scanning for tadpoles. The pool at the road crossing had a few small ones on the sand bar, but far fewer than our last trip. There were none of the large species that attached to the rocks in the faster moving parts of the streams.
Strikingly, bright green filamentous algae covered the bottom of the pool where very little had been two years before. My first guess was that the increased algae was related to the decreased grazing by tadpoles. Without the herbivorous species of tadpoles at high densities, particularly the large ones that attached to the rocks and moved across them eating the algae, the algae attached to the rocks was able to increase dramatically. This is exactly the effect that Karen had describe to Matt occurring at other sites where the frogs had disappeared that got Matt started thinking about the whole-system consequences of the frog die offs. The system, even at first glace, was obviously different from 2 years ago.
As I walked up the stream there were no adult frogs at all. This same trail had so many that their calls were constant and it was difficult not to step on them two years ago. I had been dreading this since leaving the site two years before. The sound of heavy machinery in the distance had replaced the calls of the frogs that previously had filled the air along the jungle trail. The group did not talk about it. Some our group had not been there before, so could not truly understand the changes. The rest of us just did not talk about it but went about our work.
We took some samples to the truck and Edgardo drove up to help. Heidi was back at the Rescue Center and had no time to help with the research. Heidi and Edgardo had a new vehicle from their work with the North American zoos. I gave Edgardo a hug and we looked each other in the eyes. I knew he understood what I was thinking. I mentioned how depressing the loss of the frogs was. His reply was “You have no idea”. Of course I had no idea. He had worked on these frogs for years. He had dedicated is life to them.
We took a few background samples and put in some monitoring equipment. Then we drove back to the hotel and started preparations for the big field day the next morning. I got into Amanda and Piet’s room and started cleaning up the lab area. I don’t really care how people keep their personal space, but dirty and cluttered lab space leads to disorganization and lost and contaminated samples. The room was so bad otherwise that Amanda started taking showers in Matt’s and my room. The one in her room was filthy.
Cathy Pringle had arrived seperately at the hotel while we were gone. She asked if the frogs were really gone. Piet had emailed earlier that some were left. We all wanted to believe that Rio Maria would not be hit as hard as the other sites. I had seen the stream, and it was obvious what had happened. I told her how sparse they were and she shook her head.
Alex briefly talked to me about the frogs being gone, he was obviously upset. Bob did not seem as upset, but he does not share feelings, so it was difficult to tell for sure. At the time he seemed more concerned about cocktail hour. Maybe it was displacement behavior. Matt and I were rooming together and talked before we went to sleep that night. He mentioned that when he had gone through this at a previous site, he had hoped in the back of his mind that Karen Lips’ predictions about when the disease would hit and how it would decimate the frog populations, would be wrong. But she had been right. We had gone through the same thing at Rio Maria. Intellectually I knew they were gone, but the reality was not easy to bear. This time Matt knew what to expect and was not as shocked. The drinks that evening had done nothing to lift my spirits, and the mood was somber as we fell asleep.
The next morning it took us a few hours to get our gear together and head up to the stream. We got there around 10:00 am and started to work. There were 9 of us and we worked until 6:00 pm. We only heard 3 frogs calling and saw one living frog. Heidi and Edgardo grabbed it and took it to try to culture it and treat it for the disease. It would be placed in the quarantine area of the Rescue Center.
It was a long and exhausting day, and the changes in the stream became obvious as we sampled. We were moving up and down the banks of the stream using the trail that had been cut by machete two years ago. Of course the jungle regrows rapidly, and a good amount of vegetation needed to be removed to make it possible to move up and down the trail with all the equipment we had. The observation of more algae was borne out as we took more quantitative samples. There were more fish, and more invertebrates that eat algae. Some of the invertebrate larvae that relied upon the activities of the tadpoles were gone. The diversity of the tropical forest was as startling as ever, with the exception of the frogs.
No comments:
Post a Comment