7 streams transects and a lot of hiking later, our research and our time in Costa Rica is done. We changed our research question once again to address whether or not the species we ad chosen (dragonflies, damselflies, and amphibians) could be used as bioindicators in high elevation tropical streams. Given the fact that we only observed one amphibian (and it was dead), the answer to our question for amphibians was no. There are many plausible explanations for this including varying elevation habitat ranges, global amphibian decline, climate change, and rainfall reducing the dependence of amphibians on streams.
We did see enough Odonata (dragonflies and damselflies) to be able to run statistical analysis on our results.
On average we counted 4.29 Odonata species at each stream. The mean total elevation at our streams was 1331.14 m asl and average stream flow was 4.1057m/s.Our results indicated a significant positive relationship between damselfly abundance and elevation. So there were more damselflies found as elevation increased. This shows that in order to use damselflies as bioindicators, you need to correct for elevation. Streamflow rates were significantly different when compared by land use type, however the sample size was too small in order to determine which land use type caused this difference. We suspect that the difference was between primary forest and coffee land use as they were approaching significance.
We were pleasantly surprised by the significance of our results due to our very small sample size. Overall, the research was a good experience and I feel as though our team learned a lot and worked well together.
It’s been fun, Costa Rica, but I need a taco.