As we finally arrive to our research site, Las Cruces Biological Station, I am able to reflect on the previous week of merging and finalizing our research project methods and analysis. I have been paired with Caitlin and Carolyn for the remainder of the project and we were able to seamlessly merge our proposed projects into one. Caitlin’s project focused mostly on stream discharge and water quality parameters from different land use sources, and Carolyn’s project looked at the effects of acid rain on poison dart frogs. Our combined research question is “how does land use impact stream quality as well as abundance of bioindicator species”. We will be using dragonflies/damselflies as well as amphibians as bioindicators of stream health. We will also be looking at parameters of stream health in order to see the differences between certain land uses and how those land uses impact stream ecosystems. In addition, we will be looking at the possible acidification of water sources into the system, including runoff and rain. Our methods are as follows:
1. Streams will be selected based on the land use at the head of each stream; the different land use being agricultural land (coffee), deforested land, and a natural forest area (Figure 1). Three streams of each different land use will be studied (nine streams in total).
2. Starting from the source of each stream (or approximately the source), we will use a one kilometer transect and exhaustively count all dragonfly and damselfly species, as well as amphibian species we encounter every 100 meters along a fixed route along the bank. I will count all individuals at each point location along the 1 km transect for 5 minutes. This method prevents any double counts of individuals due to the brevity of each sample and the unlikelihood of dragonflies traveling more than 100 meters, as most species do not have large territories.
3. We will test certain water quality parameters at the beginning, middle and end of each stream. These parameter are stream discharge, total suspended sediment, pH, temperature.
4. In order to measure the amount of suspended particulate matter in streams, two water samples will be taken from each site, along the transect.
5. Measuring pH using litmus paper to check for acidity and temperature will be measured using a thermometer
6. Current data on rainfall acidity would be collected by testing the pH of precipitation gathered in a rain gauge in an open area near the stream transects. This information would need to be collected as soon after rainfall as possible and as often as possible within the constraints of the project.
We also developed the statistical analysis we will complete once all the data has been collected. This includes one-way ANOVA analysis and regression. The independent variable in this study is land use and the dependent variables are dragonfly and amphibian abundance and the water quality parameters. The next big step for our group is gathering all the equipment we need, discovering which streams we can use as our transects, and finally, collecting data.
Our project has the capability to provide insight into land management decisions and the necessity of protecting tropical forests. “Norman Myers, an authority on tropical conservation, has estimated that about 95,000 square miles of tropical forest are lost each year, and similar estimates have been made independently by a number of tropical forester” (Tropical Nature). Las Cruces is a great example of a preserve surrounded by fragmented land and high anthropogenic impact. If land managers do not act soon, many ecosystems, including riparian systems, could be destroyed, along with the species that inhabit them.