Project web page

Results were not in line with what I expected. My first counts were done before the pH had been tested and I was finding 5 or 6 species per count. The single highest species count was 6 species in Quebrada Grande. The single lowest count was a zero count in Rio Negro. This occurred after a heavy storm while the waters were flowing much faster than usual and the water was much less clear. The total number of different species found during this study was 7. The table below shows the species diversity average for each river and the overall average species diversity for all three rivers. The one zero count skewed my results to having an average less than was present. Without the zero count, the average would have been 5.4.

The pH's of the rivers were as follows:

Quebrada Grande pH = 7.96

Rio Negro pH = 7.47

Chirez pH = 8.04

The pH readings were suprising. Soil pH's of the area were measured by other researchers to be between 4.9 and 6.0, and there was no source of calcium carbonate to or other base that I could find to explain the increase of pH from soil to river.

Discussion:

Overall, the results that I found were in line with results that other researchers have found throughout many areas of the world. This includes temperate, subtropical, and subarctic conditions. The figure below shows how as number of samples increase, the number of expected species increases. My results fit this curve given the low number of samples I had (6 total).

Bhat, 2003

Also, a study done by J. Robinson and P. Rand published in 2005 showed a per site average species count of 7. This study was done in the southern Appalachian watershed (USA). This figure is not significantly different from my results. Despite the similarities, this research product could have benefited from more time and planning. The biggest flaw with this project was basing the study on the assumption that the pH of the rivers was going to be lower than most other areas. While this seemed like a valid assumption at the time due to the knowledge of the acidity of tropical soils, it ultimately caused the research design to be flawed. Otherwise, the project was effective at getting good samplings of the rivers. More sites and more samples would have given better results, but they were not feasible for the amount of time allotted. The method of snorkeling and observing to count the number of fish species worked for the small rivers that I sampled, but other sampling methods would be required with larger rivers. They would have also helped avoid the zero count that was obtained from Rio Negro when visibility was limited. These methods could have included cast netting, drag netting, and perhaps even electrofishing. By diversifying the methods used, results would be more accurate and consistent.