Claire Michaud Ecology Lab Andrew Tombs Wednesday, 1:50 Species Diversity in Riffles and Pools Abstract: The purpose of this study was to compare the over all fish diversities between riffle and pool channels in Butternut Creek, NY. To test this study, Simpson Diversity Index, Sorensen Coefficient of Community Similarity and Chi Square tables were conducted. Even though there were more fish found in the riffle, the pool had more species of fish therefore making it more diverse. Introduction: Streams are dynamic systems which means they are constantly changing. They are linear and typically have one direction of flow. Streams have channel features called riffles and pools. Pool-riffle channels are known to have moderate to low gradients and …show more content…
The Simpson’s Diversity Index (table 2) showed that there were 16 different species of fish in the pool with a diversity index of 8.36. In the riffle there were 9 different species and a diversity index of 1.94. These values are expected to range from one to “N”, where N is the species richness. The Sorensen’s Coefficient of Community Similarity (table 3) showed that there was eight species in common and the CCs value was .64. The CCs value is measured between 0-1. Zero means that are no species in common and one means that all species were found in both sites. The Chi- square test (table 4) compared the number of fish, Whitesucker (Catostomus commersonii) and Blacknose dace (Rhinichthys atratulus), in the pool and riffle sections. The White sucker was present in both sections, one was found in the riffle and ten were found in the pool. The Blacknose dace was also found in both sections, nine were found in the riffle section and six were found in the pool section. Two null hypotheses were made, and were partially accepted …show more content…
The pool had a total of 51 fish and 16 different species. The riffle consisted of a higher population of fish, 78 fish, but had less diversity, only having 9 different species. Another reason for the greater abundance of fish species in the pool is that pools offer a more reliable habitat when it comes to drought season (Gelwick 1990). The null hypotheses stating that the Whitesucker and Blacknose dace would be the same in the riffle and pool was partially accepted. The Whitesucker rejected the null because the X2 value was greater than 3.841. This meant that there was a difference in the populations between the two habitats. Due to the limited samples collected, there was not a substantial difference between the Blacknose dace in the riffle and pool. The Blacknose dace in failed to reject the null because the X2 value was less than 3.841. If there were more samples collected, there may have been more of the fish in one habitat than the other. In a future study, fish samples could be collected in multiple riffles and pools through out Butternut Creek. Doing this could potentially show more diversity within riffles and